Separations

17 pages, 964 KiB

Open AccessReview

New Challenges in (Bio)Analytical Sample Treatment Procedures for Clinical Applications

by Valentina Greco, Marcello Locatelli, Fabio Savini, Ugo de Grazia, Ottavia Montanaro, Enrica Rosato, Miryam Perrucci, Luigi Ciriolo, Abuzar Kabir, Halil Ibrahim Ulusoy, Cristian D’Ovidio, Imran Ali and Alessandro Giuffrida

Separations 2023, 10(1), 62; https://doi.org/10.3390/separations10010062 - 16 Jan 2023

Cited by 5 | Viewed by 2288

Abstract

The primary cause of poor and ambiguous results obtained from the bioanalytical process is the sample pre-treatment, especially in clinical analysis because it involves dealing with complex sample matrices, such as whole blood, urine, saliva, serum, and plasma. So, the aim of this [...] Read more.

The primary cause of poor and ambiguous results obtained from the bioanalytical process is the sample pre-treatment, especially in clinical analysis because it involves dealing with complex sample matrices, such as whole blood, urine, saliva, serum, and plasma. So, the aim of this review is to focus attention on the classical and new techniques of pre-treatment for biological samples used in the bioanalytical process. We discussed the methods generally used for these types of complex samples. Undoubtedly, it is a daunting task to deal with biological samples because the analyst may encounter a substantial loss of the analytes of interest, or the overall analysis may be too time-consuming. Nowadays, we are inclined to use green solvents for the environment, but without sacrificing analytical performance and selectivity. All the characteristics mentioned above should be added to the difficulty of the withdrawal of samples like blood because it can be an invasive practice. For these reasons, now we can also find in the literature the use of saliva as alternative biological samples and new techniques that do not require substantial sample pre-treatment, such as fabric phase sorptive extraction (FPSE). The text has been divided into the following two distinct parts: firstly, we described clinical applications under different subsections, such as anticancer drugs, antibiotics, vitamins, antivirals, non-steroidal anti-inflammatory drugs, statin, imidazoles, and triazoles. The second part is dedicated to sample preparation techniques for diagnostic purposes and is divided into the following different sample preparation techniques: solid-phase microextraction (SPME), microextraction by packed sorbent (MEPS), dispersive liquid–liquid microextraction (DDLME), and fabric phase sorptive extraction (FPSE). Full article

(This article belongs to the Special Issue Feature Papers in Separations from Editorial Board Members)

► Show Figures

Graphical abstract

22 pages, 5271 KiB

Open AccessArticle

Ultrasonic (US)-Assisted Electrocoagulation (EC) Process for Oil and Grease (O&G) Removal from Restaurant Wastewater

by Shefaa Omar Abu Nassar, Mohd Suffian Yusoff, Herni Halim, Nurul Hana Mokhtar Kamal, Mohammed J. K. Bashir, Teh Sabariah Binti Abd Manan, Hamidi Abdul Aziz and Amin Mojiri

Separations 2023, 10(1), 61; https://doi.org/10.3390/separations10010061 - 16 Jan 2023

Cited by 5 | Viewed by 1959

Abstract

Restaurant wastewater contains a high concentration of O&G, up to 3434 mg/L. This study aims to (a) assess the efficiency of EC combined with US methods for O&G removal in restaurant wastewater, (b) identify the optimum condition for COD degradation using EC treatment [...] Read more.

Restaurant wastewater contains a high concentration of O&G, up to 3434 mg/L. This study aims to (a) assess the efficiency of EC combined with US methods for O&G removal in restaurant wastewater, (b) identify the optimum condition for COD degradation using EC treatment via response surface methodology (RSM), and (c) determine the morphological surface of the aluminium (Al) electrode before and after EC treatment. The wastewater samples were collected from the Lembaran cafeteria at the Universiti Sains Malaysia (USM). The efficiency of EC, US, and US-EC, combined methods for O&G removal, was investigated using a batch reactor (pH 7). The interelectrode distance (ID, 2–6 cm), electrolysis time (T, 15–35 min), and current density (CD, 40–80 A/m²) were analysed, followed by RSM. The response variables were O&G (1000 mg/L) and chemical oxygen demand (COD low range, 1000 mg/L). The central composite design (CCD) with a quadratic model was used to appraise the effects and interactions of these parameters. The morphological surface of the electrode used was observed via scanning electron microscopy (SEM). The optimum removal efficiencies obtained were 95.4% (O&G) and 75.9% (COD) (ID: 2.4 cm, T: 30.5 min, and CD: 53.2 A/m²). The regression line fitted the data (R² O&G: 0.9838, and R² COD: 0.9558). The SEM images revealed that the use of US was useful in minimising cavitation on the electrode surface, which could lower the EC treatment efficacy. The US-EC combined technique is highly recommended for O&G removal from the food industry’s wastewater. Full article

(This article belongs to the Collection Recent Advances in Environmental Separations Analysis)

► Show Figures

Figure 1

19 pages, 7836 KiB

Open AccessArticle

Application of Walnut Shell Biowaste as an Inexpensive Adsorbent for Methylene Blue Dye: Isotherms, Kinetics, Thermodynamics, and Modeling

by Sabrina Farch, Madiha Melha Yahoum, Selma Toumi, Hichem Tahraoui, Sonia Lefnaoui, Mohammed Kebir, Meriem Zamouche, Abdeltif Amrane, Jie Zhang, Amina Hadadi and Lotfi Mouni

Separations 2023, 10(1), 60; https://doi.org/10.3390/separations10010060 - 16 Jan 2023

Cited by 17 | Viewed by 2505

Abstract

This research aimed to assess the adsorption properties of raw walnut shell powder (WNSp) for the elimination of methylene blue (MB) from an aqueous medium. The initial MB concentration (2–50 mg/L), the mass of the biomaterial (0.1–1 g/L), the contact time (10–120 min), [...] Read more.

This research aimed to assess the adsorption properties of raw walnut shell powder (WNSp) for the elimination of methylene blue (MB) from an aqueous medium. The initial MB concentration (2–50 mg/L), the mass of the biomaterial (0.1–1 g/L), the contact time (10–120 min), the medium’s pH (2–12), and the temperature (25–55 °C) were optimized as experimental conditions. A maximum adsorption capacity of 19.99 mg/g was obtained at an MB concentration of 50 mg/L, a medium pH of 6.93 and a temperature of 25 °C, using 0.2 g/L of WNSp. These conditions showed that the MB dye elimination process occurred spontaneously. Different analytical approaches were used to characterize the WNSp biomaterial, including functional groups involved in MB adsorption, the surface characteristics and morphological features of the WNSp before and after MB uptake, and identification of WNSp based on their diffraction pattern. The experimental isotherm data were analyzed by the Langmuir and Freundlich models for the adsorption of MB dye. The corresponding values of parameter R_L of Langmuir were between 0.51 and 0.172, which confirmed the WNSp’s favorable MB dye adsorption. The experimental kinetic data were examined, and the pseudo-second-order model was shown to be more suitable for describing the adsorption process, with an excellent determination coefficient (R² = 0.999). The exchanged standard enthalpy (H° = −22.456 KJ.mol⁻¹) was calculated using the van ‘t Hoff equation, and it was proven that the adsorption process was exothermic. The spontaneous nature and feasibility of the MB dye adsorption process on WNSp were validated by negative standard enthalpy values (G°) ranging from −2.580 to −0.469 at different temperatures. It was established that WNSp may be employed as a novel, effective, low-cost adsorbent for the elimination of methylene blue in aqueous solutions. Full article

(This article belongs to the Special Issue Development of Mesoporous Materials for Adsorption and Recovery of Metals)

► Show Figures

Figure 1

19 pages, 1466 KiB

Open AccessArticle

Moroccan Endemic Artemisia herba-alba Essential Oil: GC-MS Analysis and Antibacterial and Antifungal Investigation

by Habiba Houti, Mohamed Ghanmi, Badr Satrani, Fouad El Mansouri, Francesco Cacciola, Moulay Sadiki and Abdellatif Boukir

Separations 2023, 10(1), 59; https://doi.org/10.3390/separations10010059 - 16 Jan 2023

Cited by 12 | Viewed by 2929

Abstract

In Morocco, the endemic Artemisia herba-alba is well known by its traditional uses and health benefits. The search for natural, safe, and effective antibacterial and antifungal agents from plants is in high demand due to microbial and fungal resistance to conventional synthetic antibiotics [...] Read more.

In Morocco, the endemic Artemisia herba-alba is well known by its traditional uses and health benefits. The search for natural, safe, and effective antibacterial and antifungal agents from plants is in high demand due to microbial and fungal resistance to conventional synthetic antibiotics and antifungal drugs. In this study, the A. herba-alba was collected from the region of Fez-Boulemane during the periods of March, June, and September. Essential oils (EOs) were extracted from the aerial part of the plant by the hydrodistillation method. The chemical constituents were determined using GC-MS as analytical tools. The antimicrobial activities of different oils were tested using the macrodilution method. The results showed the difference in the yields between the three EOs (0.49, 1.74, 1.30% (mL/100 g)), respectively, as well as in their corresponding chemical compositions. The main constituents revealed by GC-MS are higher contents of oxygenated monoterpenes (84.7, 84.4, 81%), such as cis chrysanthenyl acetate (30, 26.7, 27.6%), β-thujone (23.2, 12.9, 15.4%), camphor (9.76, 14.3, 15.8%), chrysanthenone (2.4, 1, 14%), 1,8-cineole (1.5, 11.7, 11.8%), trans β-dihydroterpineol (7.8, 7.2, 6.9%), α-thujone (4.8, 3, 5.4%), and sesquiterpenic davanone (3.9, 1.5, 1.4%), respectively. The three EOs biological activities’ results showed significant antimicrobial effects against four bacteria tested (E. coli, B. subtilis, S. aureus, M. luteus), with the MIC values ranging from 0.1 to 0.03% (v/v), as well as interesting antifungal effects on both wood rot fungi against four fungi examined (G. trabeum, P. placenta, C. puteana, C. versicolor) and molds against three microorganisms tested (A. niger, P. digitatum, P. expansum), with MIC values ranging from 0.2 to 0.03% (v/v) and 0.4 to 0.03% (v/v), respectively. The June and September EO samples showed more potent activities than those collected during March. Our research findings showed quantitative variability in both EO contents and chemical compositions, which could be due to the phenological stages, climatic conditions of growth, and harvesting periods. The potent results of the antimicrobial/antifungal activities were provided by the EOs of June and September and might be correlated to the contribution and synergism effect of all oxygenated monoterpenes. These results support the possible application of A. herba-alba EOs as natural and safe antibacterial agents, and an effective alternative to synthetic drugs, enabling the prevention and treatment of certain pathogenic infections in food and health, and the preservation of wood alteration against fungi. Full article

(This article belongs to the Special Issue Separation and Quantitative Analysis of Natural Product Extracts)

► Show Figures

Figure 1

14 pages, 1785 KiB

Open AccessArticle

Highly Sensitive In-Capillary Derivatization and Field Amplified Sample Stacking to Analyze Narcotic Drugs in Human Serum by Capillary Zone Electrophoresis

by Monika Malak, Hager Ebrahim, Heba Sonbol, Ahmed Ali, Yasmine Aboulella, Ghada Hadad and Samy Emara

Separations 2023, 10(1), 58; https://doi.org/10.3390/separations10010058 - 15 Jan 2023

Cited by 5 | Viewed by 1921

Abstract

An in-capillary derivatization (in-CAP-D) integrated with field amplified sample stacking (FASS) has been developed for the determination of morphine (MOR) and its metabolite, morphine-6-glucuronide (MOR-6-G) in human serum using capillary zone electrophoresis (CZE) and fluorescence detection (in-Cap-D-FASS-CZE). Acetonitrile was employed in removing proteins [...] Read more.

An in-capillary derivatization (in-CAP-D) integrated with field amplified sample stacking (FASS) has been developed for the determination of morphine (MOR) and its metabolite, morphine-6-glucuronide (MOR-6-G) in human serum using capillary zone electrophoresis (CZE) and fluorescence detection (in-Cap-D-FASS-CZE). Acetonitrile was employed in removing proteins and extracting MOR and MOR-6-G into the clear supernatant containing codeine (COD) as an internal standard (IS). The derivatization was achieved in an in-capillary mode by introducing the acetonitrile-treated samples into a running electrolyte containing an oxidizing agent of potassium ferricyanide, whereas MOR, MOR-6-G and COD were oxidized into dimer derivatives with highly fluorescent intensity. The effectiveness and sensitivity of the in-Cap-D-FASS-CZE method were affected by many parameters, and the following conditions were found to be optimal: 70 m Mdisodium tetraboratedecahydrate (pH, 10.5), 0.30 mM ferrricyanide and a separation voltage of 10 kV. In order to perform the FASS, samples were electrokinetically injected for 20 s at 20 kV into the capillary that was pre-field with a 4 s water plug. Analysis was performed at ambient temperature (22 ± 1 °C). The method’s validation revealed good linearity with respect to peak area ratios of MOR and MOR-6-G with the IS and the corresponding concentrations over the ranges of 1–2000 and 1.2 to 2000 ng/mL, respectively. Following one oral dose of controlled-release MOR sulphate tablet, the validated in-Cap-D-FASS-CZE method successfully enabled the determination of MOR and MOR-6-G in clinical serum samples. Full article

(This article belongs to the Special Issue Sensitivity Enhancement Approaches to the Separation Techniques for Pharmaceutical Analysis and Therapeutic Drug Monitoring)

► Show Figures

Graphical abstract

15 pages, 3497 KiB

Open AccessArticle

Adsorption Performance of Zeolite for the Removal of Congo Red Dye: Factorial Design Experiments, Kinetic, and Equilibrium Studies

by Ali Imessaoudene, Sabrina Cheikh, Amina Hadadi, Nadia Hamri, Jean-Claude Bollinger, Abdeltif Amrane, Hichem Tahraoui, Amar Manseri and Lotfi Mouni

Separations 2023, 10(1), 57; https://doi.org/10.3390/separations10010057 - 15 Jan 2023

Cited by 24 | Viewed by 2709

Abstract

In the present research, zeolite is used for the removal of toxic Congo red dye from water solution. The effects of different operating conditions such as hydrogen potential (pH), contact time (time), zeolite dose (D), initial dye concentration (C₀), and ionic [...] Read more.

In the present research, zeolite is used for the removal of toxic Congo red dye from water solution. The effects of different operating conditions such as hydrogen potential (pH), contact time (time), zeolite dose (D), initial dye concentration (C₀), and ionic strength (I) are investigated for Congo red adsorption under batch mode. It was found that the adsorption process was greatly affected by the initial pH of the dye solution. The removal efficiency decreased from 97.68 to 5.22% when the pH varied from 3 to 5; thus, acidic conditions clearly improve Congo red adsorption on zeolite. At pH 3, an increase in C₀ and I and decrease in D resulted in an increase in the adsorption capacity q_e. The effects of these three parameters and their interactions were also investigated using the 2³ full factorial design experiments approach where q_e was chosen as the response. The results obtained from this method followed by the analysis of variance and the Student’s t-test show that, the influence of these parameters on dye adsorption process are in the order I < C₀ < D. The kinetic studies revealed that adsorption follows a pseudo-second-order kinetic model. The adsorption isotherms experimental data were analyzed using the Langmuir, Freundlich, and Temkin isotherms models. The Freundlich isotherm was the best-fit model to the experimental data. The fitting of kinetics and isotherm models was evaluated by using non-linear modeling, R², MSE, and RMSE. Full article

► Show Figures

Figure 1

14 pages, 1375 KiB

Open AccessArticle

Fast Triacylglycerol Fingerprinting in Edible Oils by Subcritical Solvent Chromatography

by Tania Maria Grazia Salerno, Marianna Oteri, Paola Arena, Emanuela Trovato, Danilo Sciarrone, Paola Donato and Luigi Mondello

Separations 2023, 10(1), 56; https://doi.org/10.3390/separations10010056 - 14 Jan 2023

Cited by 1 | Viewed by 1414

Abstract

Supercritical fluid chromatography (SFC) has witnessed a resurge of interest in the last decade, motivated by substantial progress in hardware capabilities and the development of specifically tailored packing materials. Meanwhile, the technique has been transitioning to the use of mobile phases in which [...] Read more.

Supercritical fluid chromatography (SFC) has witnessed a resurge of interest in the last decade, motivated by substantial progress in hardware capabilities and the development of specifically tailored packing materials. Meanwhile, the technique has been transitioning to the use of mobile phases in which an organic co-solvent is mixed to carbon dioxide under subcritical conditions (subFC). The use of a mobile phase modifier will also affect the selectivity, and extend the range of SFC-amenable compounds, including lipids. In this research, a subFC method was developed for the separation of triacylglycerols (TAGs) in edible oils of vegetable origin, namely borage, corn, hazelnut, olive, palm, peanut, and soybean oil. For all the samples investigated, elution of the TAG species was achieved within 8 min, the only exception being borage oil (14 min run), characterized by TAGs spanning in a wide range of partition number (PN 36–56), as constituted by fatty acids differing for alkyl chain lengths (CN 14–24), and degree of unsaturation (DB 0–9). The coupling to mass spectrometry (MS) detection allowed for the average parameters of fatty acid composition to be derived in the oil TAG constituents. A total of 121 TAGs were identified by subFC-MS, with reduced analysis time and solvent consumption (1.5 mL per analysis) compared to common chromatographic approaches. Key features of the method developed hereby are low toxicity, costs, and environmental impact. Notably, the achieved separations were conducted at room temperature, which is beneficial in terms of column life. Full article

(This article belongs to the Special Issue Advances in the Separation Analysis of Food Constituents, Residues, and Contaminants)

► Show Figures

Graphical abstract

3 pages, 191 KiB

Open AccessEditorial

Spectroscopic, Chromatographic, and Chemometric Techniques Applied in Food Products Characterization

by Cristina Anamaria Semeniuc and Vlad Mureșan

Separations 2023, 10(1), 55; https://doi.org/10.3390/separations10010055 - 14 Jan 2023

Viewed by 1361

Abstract

Spectroscopy is a technique indispensable for evaluating the quality of foods [...] Full article

(This article belongs to the Special Issue Spectroscopic, Chromatographic, and Chemometric Techniques Applied in Food Products Characterization)

21 pages, 13617 KiB

Open AccessArticle

Date Palm Seed Extract for Mild Steel Corrosion Prevention in HCl Medium

by Naba Jasim Mohammed, Norinsan Kamil Othman, Ahmed Jamal Abdullah Al-Gburi and Rahimi M. Yusop

Separations 2023, 10(1), 54; https://doi.org/10.3390/separations10010054 - 14 Jan 2023

Cited by 1 | Viewed by 1826

Abstract

The inhibition effects of the date palm seed extract corrosion of mild steel in 0.5 M HCl at different concentrations are investigated by potentiodynamic polarisation (PDP), electrochemical impedance spectroscopy (EIS) and weight loss tests. Additionally, this study provides a fundamental understanding of aromatic [...] Read more.

The inhibition effects of the date palm seed extract corrosion of mild steel in 0.5 M HCl at different concentrations are investigated by potentiodynamic polarisation (PDP), electrochemical impedance spectroscopy (EIS) and weight loss tests. Additionally, this study provides a fundamental understanding of aromatic adsorption on iron (Fe) surfaces. Furthermore, the surface morphology and the extracts are performed using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The maximum inhibition efficiency of 95, 96, and 91% were realised at 1400 mg/L for PDP, EIS, and weight loss, respectively. The inhibitive action of the DPS extract against mild steel corrosion in an acid solution has been supported by SEM analysis. The FTIR showed that the extract contained hydroxyl (−OH) and methoxyl (−OCH₃) functional groups. The DFT depicted the adsorption sites at the oxygen (O) and carbon (C) atoms as deduced from the Fukui functions, Mulliken atomic charge, and the highest occupied molecular orbital-lowest occupied molecular orbital (HOMO-LUMO) analysis. The DPS preferred to form chemical bonds by donating electrons to the Fe surface. The coordinate bonds between the O and C atoms and the metal surface resulted in a high inhibition efficiency value. In conclusion, date palm seed extract is an effective inhibitor to protect mild steel from corrosion in an acidic medium. Full article

(This article belongs to the Special Issue Exclusive Papers Collection of Scholars Invited by Editorial Board Members of Separations)

► Show Figures

Figure 1

17 pages, 3409 KiB

Open AccessArticle

Bioactive Chemical Constituents of Matthiola longipetala Extract Showed Antioxidant, Antibacterial, and Cytotoxic Potency

by Yasser A. El-Amier, Nouf S. Zaghloul and Ahmed M. Abd-ElGawad

Separations 2023, 10(1), 53; https://doi.org/10.3390/separations10010053 - 13 Jan 2023

Cited by 3 | Viewed by 1780

Abstract

The exploration of bioactive compounds from natural resources attracts the attention of researchers and scientists worldwide. M. longipetala is an annual aromatic herb that emits a pleasant odor during the night. Regarding the chemical composition and biological characteristics, M. longipetala extracts are poorly [...] Read more.

The exploration of bioactive compounds from natural resources attracts the attention of researchers and scientists worldwide. M. longipetala is an annual aromatic herb that emits a pleasant odor during the night. Regarding the chemical composition and biological characteristics, M. longipetala extracts are poorly studied. The current study aimed to characterize the chemical composition of M. longipetala methanol extract using GC-MS and determine its biological potencies, including its capacity for cytotoxicity and antioxidant and antibacterial activities. In this approach, 37 components were identified, representing 99.98% of the total mass. The major chemical components can be classified as oxygenated hydrocarbons (19.15%), carbohydrates (10.21%), amines (4.85%), terpenoids (12.71%), fatty acids and lipids (50.8%), and steroids (2.26%). The major identified compounds were ascaridole epoxide (monoterpene, 12.71%) and methyl (E)-octadec-11-enoate (ester of fatty acid, 12.21%). The extract of M. longipetala showed substantial antioxidant activity. Based on the DPPH and ABTS scavenging, the antioxidant activity of the extracted components of M. longipetala revealed that leaf extract is the most effective with IC₅₀ values of 31.47 and 28.94 mg/L, respectively. On the other hand, the extracted plant showed low antibacterial activities against diverse bacterial species, viz., Escherichia coli, Klebsiella pneumonia, Staphylococcus epidermidis, S. haemolyticus, and S. aureus. The most potent antibacterial results were documented for leaf and flower extracts against E. coli and S. aureus. Additionally, the extract’s effectiveness against HepG2 cells was evaluated in vitro using the measures of MTT, DNA fragmentation, and cell proliferation cycle, where it showed considerable activity. Therefore, we can conclude that M. longipetala extract displayed improvement in cytocompatibility and cell migration properties. In conclusion, M. longipetala could be considered a potential candidate for various bioactive compounds with promising biological activities. However, further characterization of the identified compounds, particularly the major compounds, is recommended to evaluate their efficacy, modes of action, and safety. Full article

(This article belongs to the Special Issue Essential Oils: Extraction, Chemical Composition, and Biological Activity)

► Show Figures

Figure 1

14 pages, 3677 KiB

Open AccessArticle

Essential Oils from Six Aromatic Plants of Langtang National Park: Insights on Their Chemical Constituents via GC-MS Analysis

by Samjhana Pradhan, Hem Raj Paudel, Romi Maharjan and Kavita Sharma

Separations 2023, 10(1), 52; https://doi.org/10.3390/separations10010052 - 13 Jan 2023

Cited by 1 | Viewed by 1615

Abstract

The present work aims to provide an insight on the chemical constituents of essential oils obtained from six aromatic plants of the Langtang National Park (LNP), Nepal. LNP harbors an enriched biodiversity of medicinal and aromatic plants (MAPs). The composition of essential oils [...] Read more.

The present work aims to provide an insight on the chemical constituents of essential oils obtained from six aromatic plants of the Langtang National Park (LNP), Nepal. LNP harbors an enriched biodiversity of medicinal and aromatic plants (MAPs). The composition of essential oils obtained from Rhododendron anthopogon D. Don, Artemisia dubia Wall. ex Besser, Boenninghausenia albiflora (Hook.) Rchb. ex Meisn., Elsholtzia fruticosa (D. Don) Rehder, Juniperus recurva Buch.-Ham. ex D. Don and Rhododendron setosum D. Don, were analyzed by Gas Chromatography-Mass Spectrometry (GC-MS). The essential oils were extracted via the hydrodistillation method using the Clevenger apparatus. GC-MS analysis showed that E-caryophyllene, α-pinene, γ-terpinene, β-pinene and δ-cadinene in Rhododendron anthopogon; santolina-triene, β-cubebene and sabinene in Artemisia dubia; β-myrcene, β-cubebene, E-β-ocimene and bicyclogermacrene in Boenninghausenia albiflora; perillene, eucalyptol and β-pinene in Elsholtzia fruticosa; δ-3-carene, cadina-1(6),4-diene and δ-cadinene in Juniperus recurva; trans-sabinyl acetate, sabinene, α-elemol and germacrene D in Rhododendron setosum are the principal components. The major compounds in the essential oil were monoterpenes and sesquiterpenes, representing almost 80% to 90% of the total constituents of the essential oil. In comparison to the previous studies, the results showed a significant difference in the qualitative composition of the essential oil. This is also the first report on the study of chemical constituents from the essential oil of R. setosum. Despite hosting a plethora of MAPs, only a limited number of studies have been carried out to identify their chemical and biological properties. Hence, further investigations on the MAPs of the Langtang region are highly essential to identify the major chemical constituents and explore their biological activities. Full article

(This article belongs to the Special Issue Novel Approach for Natural Product Separation from Plants)

► Show Figures

Graphical abstract

16 pages, 3395 KiB

Open AccessArticle

SPME-GC-MS Analysis of the Volatile Profile of Three Fresh Yarrow (Achillea millefolium L.) Morphotypes from Different Regions of Northern Italy

by Stefania Garzoli, Vittoria Cicaloni, Laura Salvini, Giacomo Trespidi, Marcello Iriti and Sara Vitalini

Separations 2023, 10(1), 51; https://doi.org/10.3390/separations10010051 - 12 Jan 2023

Cited by 2 | Viewed by 1318

Abstract

Achillea millefolium L. is the most representative plant of the genus Achillea due to its long-standing use. Previous investigations have allowed for the identification of many chemical compounds including phenols, flavonoids, monoterpenes, sesquiterpenes, and their derivatives. However, only a few reports have considered [...] Read more.

Achillea millefolium L. is the most representative plant of the genus Achillea due to its long-standing use. Previous investigations have allowed for the identification of many chemical compounds including phenols, flavonoids, monoterpenes, sesquiterpenes, and their derivatives. However, only a few reports have considered flower color in relation to A. millefolium composition. In this work, the phytochemical analysis on the volatile content of fresh samples of three morphotypes—white, pink and deep pink—collected in different points of the Italian Alpine area, was performed by the SPME-GC-MS technique. The obtained data highlighted a high content of terpenic compounds in all of the investigated morphotypes with a general predominance of monoterpenes over sesquiterpenes with the exception of the white morphotype at collection point A (Saint Marcel, Valle d’Aosta). An in-depth statistical investigation was also carried out to better interpret the distribution of the various components both in relation to the morphotype and collection point. Full article

(This article belongs to the Section Analysis of Natural Products and Pharmaceuticals)

► Show Figures

Graphical abstract

15 pages, 3221 KiB

Open AccessArticle

A Simple Stability-Indicating UPLC Method for the Concurrent Assessment of Paracetamol and Caffeine in Pharmaceutical Formulations

by Wasim Ahmad, Yousif Amin Hassan, Ayaz Ahmad, Manal Suroor, Mohammad Sarafroz, Prawez Alam, Shadma Wahab and Shahana Salam

Separations 2023, 10(1), 50; https://doi.org/10.3390/separations10010050 - 12 Jan 2023

Viewed by 2087

Abstract

A fixed-dose combination of paracetamol (PCM) and caffeine (CAF) tablets/capsules is the most frequently used over-the-counter medicine for fever and headache. In this paper, a simple, reliable, sensitive, rapid, and stability-indicating ultra-performance liquid chromatography (UPLC) analytical method was proposed for simultaneously assessing PCM [...] Read more.

A fixed-dose combination of paracetamol (PCM) and caffeine (CAF) tablets/capsules is the most frequently used over-the-counter medicine for fever and headache. In this paper, a simple, reliable, sensitive, rapid, and stability-indicating ultra-performance liquid chromatography (UPLC) analytical method was proposed for simultaneously assessing PCM and CAF in pharmaceutical formulations. The UPLC method was developed on an Acquity UPLC^® CSH^TM C₁₈ column, and the column oven temperature was maintained at 35 ± 5 °C with isocratic elution by using a solution of methanol and water (30:70, v/v). The maximum absorbance of PCM and CAF was observed at 272.5 nm. The flow rate was 0.2 mL/min, and the injection volume was 1 µL, with the total run time of 2 min for the separation of PCM and CAF. The proposed UPLC method was validated according to the ICH guidelines, and it demonstrated excellent linearity, with correlation coefficients of 0.9995 and 0.9999 over the concentration ranges of 40–400 and 7–70 ng/mL for PCM and CAF, respectively. The mean retention times of 0.82 ± 0.0 and 1.16 ± 0.02 were observed for PCM and CAF, respectively. The limits of detection and quantification were 16.62 and 3.86 for PCM, respectively, and 50.37 and 11.70 for CAF, respectively. PCM and CAF were subjected to acidic, alkali, oxidative, phytochemical, dry-heat, and wet-heat degradation. The method was found to well separate the analytes’ peaks from degradation peaks, with no alterations in retention times. The proposed method is linear, precise, accurate, specific, and robust, and it can indicate stability and be used for the quantitative assessment of pharmaceutical formulations comprising PCM and CAF within a short period of time. Full article

(This article belongs to the Special Issue Analysis of Natural Products and Synthetic Drugs by HPLC or HPTLC)

► Show Figures

Figure 1

13 pages, 3220 KiB

Open AccessArticle

Preparation, Phase Diagrams and Characterization of Fatty Acids Binary Eutectic Mixtures for Latent Heat Thermal Energy Storage

by Dongyi Zhou, Shuaizhe Xiao, Xianghua Xiao and Yicai Liu

Separations 2023, 10(1), 49; https://doi.org/10.3390/separations10010049 - 12 Jan 2023

Cited by 2 | Viewed by 2053

Abstract

A series of fatty acid binary eutectic mixtures were prepared by using capric acid, lauric acid, myristic acid, palmitic acid, and stearic acid (CA, LA, MA, PA, and SA) as raw materials. The phase diagrams of these fatty acid binary eutectic mixtures were [...] Read more.

A series of fatty acid binary eutectic mixtures were prepared by using capric acid, lauric acid, myristic acid, palmitic acid, and stearic acid (CA, LA, MA, PA, and SA) as raw materials. The phase diagrams of these fatty acid binary eutectic mixtures were drawn using the Schrader equation. The thermal properties and structure were determined using differential scanning calorimetry (DSC). The thermal stability was assessed using thermogravimetric analysis (TGA) and thermal cycling tests. DSC analysis results showed that the phase change temperature of these fatty acid binary eutectic mixtures is between 17.7 °C and 57.1 °C, and the phase change latent heat is between 145.2 J/g and 193.0 J/g. The results of TGA and thermal cycle tests showed that these fatty acid binary eutectic mixtures have good thermal stability and long-term cycle thermal reliability. These results indicated that these binary eutectic mixtures of fatty acids were suitable as thermal energy storage materials for low-temperature systems. Full article

(This article belongs to the Special Issue Advances in Separation Engineering)

► Show Figures

Graphical abstract

10 pages, 1550 KiB

Open AccessCommunication

Microbead-Beating Extraction of Polycyclic Aromatic Compounds from Seabird Plasma and Whole Blood

by Vida Moradi, Thor Halldorson, Ifeoluwa Idowu, Zhe Xia, Nipuni Vitharana, Chris Marvin, Philippe J. Thomas and Gregg T. Tomy

Separations 2023, 10(1), 48; https://doi.org/10.3390/separations10010048 - 12 Jan 2023

Cited by 1 | Viewed by 1298

Abstract

Seabirds are widely regarded as an invaluable bioindicator of environmental health. Matrices including eggs and feathers have been used as non-lethal means to assess contaminant burdens. We have developed a new approach for extraction of polycyclic aromatic compounds (PACs) from seabird plasma and [...] Read more.

Seabirds are widely regarded as an invaluable bioindicator of environmental health. Matrices including eggs and feathers have been used as non-lethal means to assess contaminant burdens. We have developed a new approach for extraction of polycyclic aromatic compounds (PACs) from seabird plasma and serum based on automated microbead-beating homogenization and extraction. Commercially available bovine serum and plasma were purposely fortified with a suite of PACs separately at three dosing levels, placed inside a custom-made stainless-steel tube containing ceramic microbeads, and subjected to an extraction process using a Precellys tissue homogenizer. Tubes were shaken forcefully in three-dimensions, facilitating high mass-transfer of PACs from the matrix into the hexane extraction solvent. The accuracy of the method ranged from 55 to 120% and limits of detection and quantitation ranged from 0.1 to 8 and 0.2 to 27 pg/μL, respectively. The method exhibited good repeatability with both inter- and intra-day repeatability < 30%. The developed method represents an effective and efficient approach to extraction of PACs from important biological matrices. Full article

(This article belongs to the Special Issue Feature Papers in Separations from Editorial Board Members)

► Show Figures

Graphical abstract

16 pages, 4368 KiB

Open AccessArticle

Evaluating the Degradation Process of Collagen Sponge and Acellular Matrix Implants In Vivo Using the Standardized HPLC-MS/MS Method

by Jianping Gao, Ye Ma, Zhenhu Guo, Yang Zhang, Fangyu Xing, Tianyang Zhang, Yingjun Kong, Xi Luo, Liming Xu and Guifeng Zhang

Separations 2023, 10(1), 47; https://doi.org/10.3390/separations10010047 - 12 Jan 2023

Cited by 3 | Viewed by 2065

Abstract

The purpose of this study was to establish a collagen determination method based on an isotope-labeled collagen peptide as an internal reference via high-performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS), and using the established method to evaluate the degradation process of collagen-based implants in [...] Read more.

The purpose of this study was to establish a collagen determination method based on an isotope-labeled collagen peptide as an internal reference via high-performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS), and using the established method to evaluate the degradation process of collagen-based implants in vivo. The specific peptide (GPAGPQGPR) of bovine type I collagen was identified with an Orbitrap mass spectrometer. Then, the quantification method based on the peptide detection with HPLC-MS/MS was established and validated, and then further used to analyze the degradation trend of the collagen sponge and acellular matrix (ACM) in vivo at 2, 4, 6, 8, 12, 16, and 18 weeks after implantation. The results indicate that the relative standard deviation (RSD) of the detection precision and repeatability of the peptide-based HPLC-MS/MS quantification method were 3.55% and 0.63%, respectively. The limitations of quantification and detection were 2.05 × 10⁻³ μg/mL and 1.12 × 10⁻³ μg/mL, respectively. The collagen sponge and ACM were completely degraded at 10 weeks and 18 weeks, respectively. Conclusion: A specific peptide (GPAGPQGPR) of bovine type I collagen was identified with an Orbitrap mass spectrometer, and a standardized HPLC-MS/MS-based internal reference method for the quantification of bovine type I collagen was established. The method can be used for the analysis of the degradation of collagen-based implants in vivo. Full article

(This article belongs to the Special Issue Chromatography-Mass Spectrometry Technology Research)

► Show Figures

Graphical abstract

14 pages, 2611 KiB

Open AccessCommunication

The Influence of the Chemical Composition of Natural Waters about the Triclocarban Sorption on Pristine and Irradiated MWCNTs

by Georgeta Ramona Ivan, Ion Ion, Luiza Capra, Ovidiu Oprea and Alina Catrinel Ion

Separations 2023, 10(1), 46; https://doi.org/10.3390/separations10010046 - 11 Jan 2023

Cited by 2 | Viewed by 1027

Abstract

The influence of the chemical composition of natural waters on triclocarban (TCC) sorption on pristine and irradiated multi-walled carbon nanotubes (MWCNTs) at different temperatures was studied. Natural waters have been characterized in terms of the concentrations of cations and anions, pH, and electric [...] Read more.

The influence of the chemical composition of natural waters on triclocarban (TCC) sorption on pristine and irradiated multi-walled carbon nanotubes (MWCNTs) at different temperatures was studied. Natural waters have been characterized in terms of the concentrations of cations and anions, pH, and electric conductivity. The sorption process of TCC on MWCNTs is influenced by both the chemical composition of natural waters and the variation of the temperature. The adsorption capacity of TCC on pristine and irradiated MWCNTs in the studied natural waters increased by increasing the temperature. The increase of the concentration of monovalent cations (Na⁺ and K⁺) in natural waters determined a significant decrease of the adsorption capacity of TCC on both pristine and irradiated MWCNTs while the increase of the bivalent cations (Ca²⁺ and Mg²⁺) determined an easy increase adsorption capacity. Freundlich and Langmuir models were selected to describe the steady adsorption of the TCC on the pristine and irradiated MWCNTs. Full article

(This article belongs to the Special Issue Removal of Emerging Pollutants and Environmental Analysis)

► Show Figures

Figure 1

14 pages, 1677 KiB

Open AccessArticle

Multiple Heart-Cutting Two-Dimensional HPLC-UV Achiral–Chiral Analysis of Branched-Chain Amino Acids in Food Supplements under Environmentally Friendly Conditions

by Ina Varfaj, Simone Moretti, Federica Ianni, Carolina Barola, Ghaid W. A. Abualzulof, Andrea Carotti, Lina Cossignani, Roberta Galarini and Roccaldo Sardella

Separations 2023, 10(1), 45; https://doi.org/10.3390/separations10010045 - 11 Jan 2023

Cited by 5 | Viewed by 2065

Abstract

A multiple heart-cutting (mLC-LC) two-dimensional HPLC-UV achiral–chiral method for the direct analysis of branched-chain amino acids (BCAAs) in food supplements under environmentally friendly conditions was developed to cope with the very well-known limited chemoselectivity of chromatographic media for enantioselective analysis. Both achiral and [...] Read more.

A multiple heart-cutting (mLC-LC) two-dimensional HPLC-UV achiral–chiral method for the direct analysis of branched-chain amino acids (BCAAs) in food supplements under environmentally friendly conditions was developed to cope with the very well-known limited chemoselectivity of chromatographic media for enantioselective analysis. Both achiral and chiral methods were developed in compliance with the main principles of green chromatography. The achiral analysis was performed isocratically with an optimized ion-pair reversed-phase (IP-RP) method based on a water/EtOH (95:5, v/v) mobile phase containing heptafluorobutyric acid (7 mM) as the IP agent. The achiral method was characterized by a very appreciable performance and was validated before the analysis of the real sample. High recovery values for all compounds (from 97% to 101%) were found in the interday evaluation. Additionally, low RSD% values in the long-term period were measured, in the range between 1.1% and 4.8%. Still, an LOQ value of 0.06 mg/mL was established for all compounds. The quantitative analysis of a commercial food supplement revealed that BCAAs were present in amounts very close to those declared by the producer. The enantioselective analysis was carried out through the application of the chiral ligand-exchange chromatography (CLEC) approach, using O-benzyl-(S)-serine ((S)-OBS, 0.5 mM) as the chiral selector and Cu(II) nitrate (0.25 mM) as the metal source in the eluent. Resolution and separation factor values up to 2.31 and 1.43, respectively, were obtained. The two chromatographic systems were connected through a six-port switching valve, and the developed two-dimensional mLC-LC method confirmed the absence of D-enantiomers of BCAAs in the food supplement, as reported in the manufacturer’s label. Full article

(This article belongs to the Special Issue Recent Advances in Microextraction Technology for Analytical Sample Preparation)

► Show Figures

Figure 1

15 pages, 1348 KiB

Open AccessEditor’s ChoiceArticle

Improved Method for the Detection of Highly Polar Pesticides and Their Main Metabolites in Foods of Animal Origin: Method Validation and Application to Monitoring Programme

by Emanuela Verdini, Veronica Maria Teresa Lattanzio, Biancamaria Ciasca, Laura Fioroni and Ivan Pecorelli

Separations 2023, 10(1), 44; https://doi.org/10.3390/separations10010044 - 10 Jan 2023

Cited by 2 | Viewed by 2149

Abstract

The application of polar pesticides in agricultural production has been of great interest due to their low costs and their high effectiveness. For this reason, the possibility of their transfer to foods of animal origin is of great concern for human health. The [...] Read more.

The application of polar pesticides in agricultural production has been of great interest due to their low costs and their high effectiveness. For this reason, the possibility of their transfer to foods of animal origin is of great concern for human health. The manuscript describes the implementation and validation of an analytical method to detect polar pesticides, at regulatory levels, in three foods of animal origin, including bovine fat, chicken eggs, and cow milk. The method was fully validated to detect glyphosate, glufosinate, and their respective metabolites in the above-mentioned foods obtaining fit-for-purpose sensitivity, recoveries (76–119%), repeatability (≤20%), within-laboratory reproducibility (≤20%), and experimental measurement uncertainty less than 50% as required by the SANTE/11312/2021 criteria. Given the satisfactory results, the applicability of the method to additional molecules belonging to the same category (AMPA, cyanuric acid, ethephon, fosetyl aluminum, HEPA, maleic hydrazide, and N-acetyl-glyphosate) was also evaluated in order to meet possible future requests. Finally, the implemented method was applied to analyse samples over the period of March 2021 to August 2022 from two Italian regions (Umbria and Marche) within the national monitoring programme. In agreement with previously available data, none of the samples analysed showed the presence of glyphosate and glufosinate at levels above the legal limit. Full article

(This article belongs to the Special Issue Determination and Bio-Implications of Organic Pollutants in Food and Environmental Samples Based on Hyphenated Techniques)

► Show Figures

Figure 1

13 pages, 3619 KiB

Open AccessArticle

Effective and Low-Cost Adsorption Procedure for Removing Chemical Oxygen Demand from Wastewater Using Chemically Activated Carbon Derived from Rice Husk

by Wael I. Mortada, Raed A. Mohamed, Amir A. Abdel Monem, Marwa M. Awad and Asaad F. Hassan

Separations 2023, 10(1), 43; https://doi.org/10.3390/separations10010043 - 10 Jan 2023

Cited by 9 | Viewed by 2300

Abstract

Wastewater treatment by adsorption onto activated carbon is effective because it has a variety of benefits. In this work, activated carbon prepared from rice husk by chemical activation using zinc chloride was utilized to reduce chemical oxygen demand from wastewater. The as-prepared activated [...] Read more.

Wastewater treatment by adsorption onto activated carbon is effective because it has a variety of benefits. In this work, activated carbon prepared from rice husk by chemical activation using zinc chloride was utilized to reduce chemical oxygen demand from wastewater. The as-prepared activated carbon was characterized by scanning electron microscope, Fourier transform infrared spectroscopy and nitrogen adsorption/desorption analysis. The optimum conditions for maximum removal were achieved by studying the impact of various factors such as solution pH, sorbent dose, shaking time and temperature in batch mode. The results displayed that the optimum sorption conditions were achieved at pH of 3.0, sorbent dose of 0.1 g L⁻¹, shaking time of 100 min and at room temperature (25 °C). Based on the effect of temperature, the adsorption process is exothermic in nature. The results also implied that the isothermal data might be exceedingly elucidated by the Langmuir model. The maximum removal of chemical oxygen demand by the activated carbon was 45.9 mg g⁻¹. The kinetic studies showed that the adsorption process follows a pseudo-first order model. The findings suggested that activated carbon from rice husk may be used as inexpensive substitutes for commercial activated carbon in the treatment of wastewater for the removal of chemical oxygen demand. Full article

► Show Figures

Graphical abstract

12 pages, 2272 KiB

Open AccessArticle

Separation of Cesium and Rubidium from Solution with High Concentrations of Potassium and Sodium

by Junjie Xie, Kang Li, Zhuonan Shi, Changli Min, Shina Li, Zichen Yin and Ruixin Ma

Separations 2023, 10(1), 42; https://doi.org/10.3390/separations10010042 - 09 Jan 2023

Cited by 1 | Viewed by 1331

Abstract

Solvent extraction with 4-tert-butyl-2-(α-methylbenzyl) phenol (t-BAMBP) is an effective method for the separation and purification of rubidium and cesium. A solution containing a high K⁺ concentration (exceeding 80 g/L), which was ultra-salty, with about 200 g/L alkali metal ions, was used to [...] Read more.

Solvent extraction with 4-tert-butyl-2-(α-methylbenzyl) phenol (t-BAMBP) is an effective method for the separation and purification of rubidium and cesium. A solution containing a high K⁺ concentration (exceeding 80 g/L), which was ultra-salty, with about 200 g/L alkali metal ions, was used to extract Rb⁺ and Cs⁺. The effects of the process parameters on the separation of cesium and rubidium were systematically studied. The optimum conditions were as follows: NaOH concentration of 0.5 mol/L, t-BAMBP concentration of 1 mol/L (in sulfonated kerosene), organic/aqueous volume ratio (O/A ratio) of 3:1, and contact time of 1 min. The extraction rates of cesium and rubidium were 99.81 and 98.09%, respectively, and 19.31% of potassium was co-extracted in the organic phase after five-stage countercurrent extraction. About 99.32% of K⁺ in the organic phase could be removed after five-stage countercurrent scrubbing with deionized water at an O/A ratio of 2:1 for 2 min. When 0.5 mol/L hydrochloric acid solution was used as detergent, almost all of the cesium and rubidium (>99%) could be recovered by two-stage countercurrent stripping at an O/A ratio of 3:1 for 2 min. A solid compound was found and collected from the organic phase during multi-stage solvent extraction. Its composition and structure were determined by XRD, infrared Fourier-transform, and ICP-MS. Full article

(This article belongs to the Special Issue Research on Extraction Technology, Separation Methods and Metal Recovery)

► Show Figures

Graphical abstract

13 pages, 2782 KiB

Open AccessArticle

Study on the Performance of Cellulose Triacetate Hollow Fiber Mixed Matrix Membrane Incorporated with Amine-Functionalized NH₂-MIL-125(Ti) for CO₂ and CH₄ Separation

by Naveen Sunder, Yeong-Yin Fong, Mohamad Azmi Bustam and Woei-Jye Lau

Separations 2023, 10(1), 41; https://doi.org/10.3390/separations10010041 - 09 Jan 2023

Cited by 2 | Viewed by 1528

Abstract

The increase in the global population has caused an increment in energy demand, and therefore, energy production has to be maximized through various means including the burning of natural gas. However, the purification of natural gas has caused CO₂ levels to increase. [...] Read more.

The increase in the global population has caused an increment in energy demand, and therefore, energy production has to be maximized through various means including the burning of natural gas. However, the purification of natural gas has caused CO₂ levels to increase. Hollow fiber membranes offer advantages over other carbon capture technologies mainly due to their large surface-to-volume ratio, smaller footprint, and higher energy efficiency. In this work, hollow fiber mixed matrix membranes (HFMMMs) were fabricated by utilizing cellulose triacetate (CTA) as the polymer and amine-functionalized metal-organic framework (NH₂-MIL-125(Ti)) as the filler for CO₂ and CH₄ gas permeation. CTA and NH₂-MIL-125(Ti) are known for exhibiting a high affinity towards CO₂. In addition, the utilization of these components as membrane materials for CO₂ and CH₄ gas permeation is hardly found in the literature. In this work, NH₂-MIL-125(Ti)/CTA HFMMMs were spun by varying the air gap ranging from 1 cm to 7 cm. The filler dispersion, crystallinity, and functional groups of the fabricated HFMMMs were examined using EDX mapping, SEM, XRD, and FTIR. From the gas permeation testing, it was found that the NH₂-MIL-125(Ti)/CTA HFMMM spun at an air gap of 1 cm demonstrated a CO₂/CH₄ ideal gas selectivity of 6.87 and a CO₂ permeability of 26.46 GPU. Full article

(This article belongs to the Special Issue Membrane Preparation and Application for Separations and Water Treatment)

► Show Figures

Figure 1

11 pages, 1071 KiB

Open AccessArticle

Comparison of Digestion Methods Using Atomic Absorption Spectrometry for the Determination of Metal Levels in Plants

by Insaf Bankaji, Rim Kouki, Nesrine Dridi, Renata Ferreira, Saida Hidouri, Bernardo Duarte, Noomene Sleimi and Isabel Caçador

Separations 2023, 10(1), 40; https://doi.org/10.3390/separations10010040 - 09 Jan 2023

Cited by 10 | Viewed by 4019

Abstract

Trace metal elements (TMEs) are among the most important types of pollutants in the environment. Therefore, a precise determination of these contaminants in several environmental components is required for the safety assurance of living organisms. Spectroscopic analysis is an efficient technique employed to [...] Read more.

Trace metal elements (TMEs) are among the most important types of pollutants in the environment. Therefore, a precise determination of these contaminants in several environmental components is required for the safety assurance of living organisms. Spectroscopic analysis is an efficient technique employed to detect and determine TME contents in numerous samples. Hence, to achieve reliable and accurate results when using spectroscopic analysis, samples should be carefully prepared. In the present study, the comparison of eight digestion methods of five vegetal samples was carried out to quantify Cd, Mn, Al and Mg contents using the atomic absorption spectroscopy technique. According to the extraction techniques used in this study, results showed an outstanding difference in TME levels determined in the same vegetal sample. The results obtained indicated that the highest Mn concentrations were recorded when using the mixture of HNO₃-HClO₄ in the studied species: atriplex portulacoides, arthrocnemum indicum, olea europaea BCR-62, ulva lactuca and ulva lactuca BCR-279 compared to all other methods. Regarding the extraction of Cd, our results showed that heated extraction using different acids (HNO₃-H₂SO₄-HClO₄, HCl-HNO₃, HNO₃-HClO₄, HNO₃-H₂SO₄, HNO₃-HCl-HClO₄ and HNO₃-HCl-H₂SO₄) was the most efficient in atriplex portulacoides, arthrocnemum indicum, olea europaea BCR-62, ulva lactuca and ulva lactuca BCR-279. Similarly, these heated acid digestion techniques (efficient for Cd) showed the highest levels of Al in atriplex portulacoides and arthrocnemum indicum. However, for the Mg extraction, our results revealed that the effectiveness of the method used depended on the plant species studied. Regarding these findings, the efficiency of metal quantification by AAS depends on the digestion procedure, the metallic ion to determine and the plant species. Full article

(This article belongs to the Section Environmental Separations)

► Show Figures

Graphical abstract

12 pages, 2183 KiB

Open AccessArticle

Development and Validation of a Stability-Indicating Greener HPTLC Method for the Estimation of Flufenamic Acid

by Prawez Alam, Faiyaz Shakeel, Mohammed H. Alqarni, Ahmed I. Foudah, Tariq M. Aljarba, Mohammed M. Ghoneim, Syed Mohammed Basheeruddin Asdaq and Sultan Alshehri

Separations 2023, 10(1), 39; https://doi.org/10.3390/separations10010039 - 08 Jan 2023

Cited by 5 | Viewed by 1241

Abstract

The literature on ecofriendly/greener high-performance thin-layer chromatographic (HPTLC) methods for quantifying flufenamic acid (FFA) is scant. In order to develop and validate a stability-indicating greener HPTLC densitometry assay for FFA determination in marketed products, this research was conducted. The ecofriendly eluent system was [...] Read more.

The literature on ecofriendly/greener high-performance thin-layer chromatographic (HPTLC) methods for quantifying flufenamic acid (FFA) is scant. In order to develop and validate a stability-indicating greener HPTLC densitometry assay for FFA determination in marketed products, this research was conducted. The ecofriendly eluent system was composed of ethanol–water (70:30 v/v). FFA was measured at 290 nm of wavelength. The greenness scale of suggested analytical assay was derived using “Analytical GREENness (AGREE)” methodology. The suggested stability-indicating HPTLC assay was linear for FFA determination in 25–1400 ng/band range with a determination coefficient of 0.9974. The suggested analytical assay for FFA analysis was simple, rapid, accurate, precise, robust, selective, stability-indicating, and greener. The AGREE scale for the developed stability-indicating HPTLC assay was derived to be 0.77 utilizing AGREE methodology, indicating an outstanding greenness characteristic of the suggested densitometry technique. The ecofriendly HPTLC technique was able to detect FFA degradation product under forced degradation studies, indicating its stability-indication characteristics and selectivity. The amount of FFA in marketed tablets brand A and B was determined to be 101.28 and 99.17%, respectively, indicating the suitability of the suggested analytical technique in the assay of FFA in marketed products. These results indicated that FFA in marketed products may be routinely measured using the stability-indicating greener HPTLC technique. Full article

(This article belongs to the Special Issue Analysis of Natural Products and Synthetic Drugs by HPLC or HPTLC)

► Show Figures

Figure 1

13 pages, 1644 KiB

Open AccessArticle

Determination of Cordycepin Using a Stability-Indicating Greener HPTLC Method

by Prawez Alam, Faiyaz Shakeel, Mohammed H. Alqarni, Ahmed I. Foudah, Tariq M. Aljarba, Aftab Alam, Mohammed M. Ghoneim, Syed Mohammed Basheeruddin Asdaq, Sultan Alshehri and Muzaffar Iqbal

Separations 2023, 10(1), 38; https://doi.org/10.3390/separations10010038 - 08 Jan 2023

Cited by 3 | Viewed by 1254

Abstract

A wide range of analytical techniques have been reported to determine cordycepin (CDN) in various sample matrices. Nevertheless, greener analytical approaches for CDN estimation are scarce in the literature. As a result, this study was designed to develop and validate a stability-indicating greener [...] Read more.

A wide range of analytical techniques have been reported to determine cordycepin (CDN) in various sample matrices. Nevertheless, greener analytical approaches for CDN estimation are scarce in the literature. As a result, this study was designed to develop and validate a stability-indicating greener “high-performance thin-layer chromatography (HPTLC)” technique for CDN determination in a laboratory-developed formulation. The greener eluent system for CDN detection was ethanol–water (75:25 v/v). At a wavelength of 262 nm, CDN was measured. The greenness scale of the proposed analytical technology was derived using the “Analytical GREENness (AGREE)” approach. The proposed stability-indicating HPTLC assay was linear for CDN analysis in the 50–1000 ng/band range with a determination coefficient of 0.9978. The proposed analytical technique for CDN analysis was simple, rapid, accurate, precise, robust, selective, stability-indicating, and greener. The AGREE score for the proposed stability-indicating HPTLC technique was calculated to be 0.79 using the AGREE calculator. The current protocol was able to detect CDN degradation products under various stress conditions, indicating its stability-indication characteristics and selectivity. The AGREE quantitative score indicated that the stability-indicating current protocol had outstanding greener characteristics. The amount of CDN in the laboratory-developed formulation was determined to be 98.84%, indicating the suitability of the current protocol in the assay of CDN in the formulations. These results suggested that CDN in a laboratory-developed formulation may be regularly determined using the stability-indicating greener HPTLC strategy. Full article

(This article belongs to the Section Analysis of Natural Products and Pharmaceuticals)

► Show Figures

Figure 1

14 pages, 2878 KiB

Open AccessArticle

Two Stability Indicating Chromatographic Methods: TLC Densitometric versus HPLC Method for the Simultaneous Determination of Brinzolamide and Timolol Maleate in Ophthalmic Formulation in the Presence of Probable Carcinogenic Oxidative Degradation Product of Timolol Maleate

by Asmaa A. Mandour, Nada Nabil, Hala E. Zaazaa, Munjed M. Ibrahim and Mohamed A. Ibrahim

Separations 2023, 10(1), 37; https://doi.org/10.3390/separations10010037 - 06 Jan 2023

Cited by 2 | Viewed by 1712

Abstract

A comparative study between two stability-indicating chromatographic methods for the assay of brinzolamide and timolol maleate in the co-existence of the probable carcinogenic oxidative degradation product of timolol maleate in their ophthalmic formulation was demonstrated. The first method established the thin-layer chromatography coupled [...] Read more.

A comparative study between two stability-indicating chromatographic methods for the assay of brinzolamide and timolol maleate in the co-existence of the probable carcinogenic oxidative degradation product of timolol maleate in their ophthalmic formulation was demonstrated. The first method established the thin-layer chromatography coupled with the densitometric determination of the analyzed spots, using silica gel TLC aluminum plates F254 and a developing system of chloroform: methanol: ammonia (6:1:0.1, in volumes) at room temperature to give good separation for the three investigated components, where retardation factors for the oxidative degradation product of timolol maleate, brinzolamide and timolol maleate were (Rf 0.21), (Rf 0.46), and (Rf 0.55), respectively. The linear ranges were 2–10 and 3–16 μg/band for brinzolamide and timolol maleate, respectively. In the second method, high performance liquid chromatography (HPLC), photo diode array detection was used on a Eurospher 5 µm C18 100 Å (4.6 × 250 mm) column, using triethylamine pH 3.5, adjusted by glacial acetic acid: acetonitrile (20:80, v/v) at a rate of 0.5 mL per minute. An acceptable separation was achieved, where the retention times for timolol maleate, the oxidative degradation product of timolol maleate and brinzolamide, were (Rt 3.6), (Rt 4.7), and (Rt 5.6), respectively. Linearity covered a range of 20–120 μg/mL for both drugs. It has been proved previously that timolol maleate is liable to oxidation, giving a high-probability carcinogenic product in female mice. The validation for the new proposed stability-indicating methods was optimized in line with the ICH guidelines with good outcomes. It is worth noting that the HPLC-DAD method showed superior separation, economic and time-saving results, while TLC method was more sensitive. Full article

(This article belongs to the Section Chromatographic Separations)

► Show Figures

Figure 1

15 pages, 2182 KiB

Open AccessReview

Lectin Purification through Affinity Chromatography Exploiting Macroporous Monolithic Adsorbents

by Josiane F. da Silva, Clara M. G. Lima, Débora L. da Silva, Ivonea S. do Nascimento, Sarah de O. Rodrigues, Letícia A. Gonçalves, Renata F. Santana, Waseem Khalid, Silvani Verruck, Talha Bin Emran, Irwin R. A. de Menezes, Henrique D. M. Coutinho, Mayeen U. Khandaker, Mohammad R. I. Faruque and Rafael da C. I. Fontan

Separations 2023, 10(1), 36; https://doi.org/10.3390/separations10010036 - 06 Jan 2023

Viewed by 2353

Abstract

Growing medical, engineering, biochemical, and biological interest has led to a steady pace of research and development into polymeric monolithic structures with densely interconnected pores for purifying bio compounds. Cryogels, which are generated by freezing a reactive polymerization mixture, are highlighted due to [...] Read more.

Growing medical, engineering, biochemical, and biological interest has led to a steady pace of research and development into polymeric monolithic structures with densely interconnected pores for purifying bio compounds. Cryogels, which are generated by freezing a reactive polymerization mixture, are highlighted due to their versatility and low relative cost as macroporous, polymeric, monolithic adsorbents. The conversion of cryogels into affinity adsorbents is one possible alternative to their optimal application. Some of the most often utilized supports for immobilizing particular ligands are monolithic columns manufactured with epoxy radicals on their surfaces. The purification of biomolecules with a high degree of specificity, such as lectins and glycoproteins with an affinity for glycosylated groups, has garnered interest in the use of fixed non-traditional beds functionalized with ligands of particular interest. The interaction is both robust enough to permit the adsorption of glycoproteins and reversible enough to permit the dissociation of molecules in response to changes in the solution’s pH. When compared to other protein A-based approaches, this one has been shown to be more advantageous than its counterparts in terms of specificity, ease of use, and cost-effectiveness. Information on polymeric, macroporous, monolithic adsorbents used in the affinity chromatographic purification of lectins has been published and explored. Full article

(This article belongs to the Special Issue Exclusive Papers Collection of Scholars Invited by Editorial Board Members of Separations)

► Show Figures

Figure 1

12 pages, 11497 KiB

Open AccessArticle

Bioassay-Guided Isolation and Identification of Antibacterial Components against Escherichia coli from Industrial Hemp Leaves

by Yafen Fu, Siyuan Zhu, Shengwen Duan and Liangliang Liu

Separations 2023, 10(1), 35; https://doi.org/10.3390/separations10010035 - 06 Jan 2023

Cited by 1 | Viewed by 1914

Abstract

Industrial hemp leaves have raised much interest in nutraceuticals and functional foods areas. To expand its application ranges, the antibacterial activities of industrial hemp leaf extract on Escherichia coli, Staphylococcus aureus, and Bacillus cereus were evaluated and the active components were [...] Read more.

Industrial hemp leaves have raised much interest in nutraceuticals and functional foods areas. To expand its application ranges, the antibacterial activities of industrial hemp leaf extract on Escherichia coli, Staphylococcus aureus, and Bacillus cereus were evaluated and the active components were screened. As a result, the industrial hemp leaf extract was found to have strong bacteriostatic effects on E. coli and S. aureus. Bioassay-guided fractionation and isolation from fractions active against E. coli were conducted. Two compounds, cannabidivarinic acid and cannabidiolic acid, were firstly recognized by analytical HPLC by comparing the retention times and UV spectra with standards and later isolated using preparative HPLC. Moreover, the antibacterial mechanisms of cannabidivarinic acid and cannabidiolic acid were investigated by testing the alkaline phosphatase activity, β-galactosidase activity, conductivity, proteins leakage, nucleic acid leakage, and scanning electron microscope observation. The results demonstrated that cannabidivarinic acid and cannabidiolic acid could destroy the cell wall and membrane of E. coli, resulting in the inhibition of enzyme activity and leakage of contents. They could damage the bacteria cell envelope as well. Presented results pointed out cannabidivarinic acid and cannabidiolic acid as promising natural bacteriostatic agents for the food, pharmaceutical, and cosmetic industry. Full article

(This article belongs to the Special Issue Advances in Chromatographic Analysis of Bioactive Compounds)

► Show Figures

Figure 1

12 pages, 1235 KiB

Open AccessArticle

Liquid Chromatography Fingerprint Analysis of Released Compounds in Plasma Samples of Stroke Patients after Thrombolytic Treatment

by Mar Castellanos, Dolores Fernández-Couto, Andrés Da Silva-Candal, Maria J. Feal-Painceiras, Manuel Rodríguez-Yáñez, Carme Gubern-Mérida and Juan M. Sanchez

Separations 2023, 10(1), 34; https://doi.org/10.3390/separations10010034 - 05 Jan 2023

Cited by 1 | Viewed by 1463

Abstract

Plasma samples obtained from stroke patients treated with recombinant tissue-type plasminogen activator (rt-PA) and not treated with rt-PA were evaluated with different HPLC methodologies to obtain information about the possible release of small molecules as a result of the thrombolytic treatment. Plasma samples, [...] Read more.

Plasma samples obtained from stroke patients treated with recombinant tissue-type plasminogen activator (rt-PA) and not treated with rt-PA were evaluated with different HPLC methodologies to obtain information about the possible release of small molecules as a result of the thrombolytic treatment. Plasma samples, without derivatization and derivatized with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC), were evaluated with a HPLC gradient method, which consisted of a mobile phase of 10 mM ammonium acetate buffered solution (pH = 5.3) and acetonitrile. Three different detection methods were applied: UV, fluorescence, and ESI-MS. The results obtained showed that a group of new highly hydrophilic compounds appeared in most samples analyzed from treated patients, just after the administration of rt-PA. These compounds appeared shortly after the administration of the drug and were detected during the first 24 h after treatment, disappearing from plasma after this time. These new compounds were not detected either in controls or in non-treated stroke patients, which suggests that they were released into the plasma as a consequence of the thrombolytic effect of the drug. Our results suggest that these new compounds might be free glycans. The use of AQC as a derivatizing reagent has demonstrated that the new compounds detected cannot contain primary or secondary amine groups in their structure. The molecular mass determined by ESI-MS (821 Da) suggests that if these compounds are free glycans they might be a high-mannose type. Full article

(This article belongs to the Special Issue Chromatographic Analysis of Biological Samples)

► Show Figures

Graphical abstract

13 pages, 2038 KiB

Open AccessArticle

Preparation of Hydrolyzed Sugarcane Molasses as a Low-Cost Medium for the Mass Production of Probiotic Lactobacillus paracasei ssp. paracasei F19

by Elsa Acosta-Piantini, Elena Rodríguez-Díez, María Chavarri, Iratxe López-de-Armentia, M. Carmen Villaran and José Ignacio Lombraña

Separations 2023, 10(1), 33; https://doi.org/10.3390/separations10010033 - 05 Jan 2023

Cited by 6 | Viewed by 3855

Abstract

In this study, sugarcane molasses (SCM) was pre-treated in a low-cost fermentation medium to produce probiotic biomass of Lactobacillus paracasei ssp. paracasei F19 (LPPF19) with the combination of dilution, centrifugation, and acid hydrolysis (5 molar sulfuric acid, 60 °C/2 h). Microtox analysis, inductively [...] Read more.

In this study, sugarcane molasses (SCM) was pre-treated in a low-cost fermentation medium to produce probiotic biomass of Lactobacillus paracasei ssp. paracasei F19 (LPPF19) with the combination of dilution, centrifugation, and acid hydrolysis (5 molar sulfuric acid, 60 °C/2 h). Microtox analysis, inductively coupled mass spectrometry (ICP-MS), and high-performance liquid chromatography (HPLC) were used to measure the effects of SCM pretreatment on the fermentation process. The results showed that the hydrolysis of sucrose into glucose and fructose was 98%, which represented an increase of 44.4% in the initial glucose content (fermentation-limiting sugar), and harmful heavy metals, such as arsenic, cadmium, and lead, were reduced by 50.3, 60.0, and 64.3%, respectively. After pretreatment, with the supplementation of only yeast extract and salts (Na, K, Mg, and Mn), a biomass of 9.58 log CFU/mL was achieved, approximately ten times higher than that for the control medium used (MRS/DeMan, Rogosa, and Sharpe). The cost reduction achieved compared to this commercial medium was 68.7% in the laboratory and 78.9% on an industrial scale. This work demonstrated that SCM could be used in a cheaper and more effective alternative fermentation to produce LPPF19. Full article

► Show Figures

Graphical abstract

Journal Menu

Journal Browser

Separations, Volume 10, Issue 1 (January 2023) – 62 articles

Further Information

Guidelines

MDPI Initiatives

Follow MDPI