Separations

11 pages, 1658 KiB

Open AccessArticle

Artemisinin DNA Base Interaction Studies in Presence of Fe(II): LC/TOF MS Separation of Reaction Products

by Kogila Oke and Amos Mugweru

Separations 2021, 8(9), 161; https://doi.org/10.3390/separations8090161 - 18 Sep 2021

Cited by 1 | Viewed by 1321

Artemisinin (ART) is a sesquiterpene lactone and a popular malaria drug with potential anticancer properties. In this work, LC/TOF/MS, was used to investigate the reaction of ART with DNA bases. ART-deoxyadenosine and ART-deoxycytidine interactions, were studied in the presence of iron II ions. [...] Read more.

Artemisinin (ART) is a sesquiterpene lactone and a popular malaria drug with potential anticancer properties. In this work, LC/TOF/MS, was used to investigate the reaction of ART with DNA bases. ART-deoxyadenosine and ART-deoxycytidine interactions, were studied in the presence of iron II ions. ART-deoxyadenosine and ART-deoxycytidine reaction mixtures gave chromatographic signatures that remained fairly unchanged at room temperature but grew after incubation at 37 °C. The change in temperature from room temperature to 37 °C was the main driver of adduct formation in these reactions. ART was found to react with Fe(II) ions as observed from several new chromatographic peaks. ART-deoxyadenosine as well as ART-deoxycytidine in the presence of Fe(II) ions resulted in formation of new chromatographic signatures of adducts consisting of DNA bases and ART. It was clear that addition of iron (II) to DNA base-ART mixtures gave rise to new reaction products mediated by a different reaction mechanism. Studies of ART reactions with DNA in vitro is key in elucidating elusive mechanism of this drug. Full article

► Show Figures

Figure 1

15 pages, 14572 KiB

Open AccessArticle

The Use of an Unmanned Aerial Vehicle for Tree Phenotyping Studies

by Shara Ahmed, Catherine E. Nicholson, Paul Muto, Justin J. Perry and John R. Dean

Separations 2021, 8(9), 160; https://doi.org/10.3390/separations8090160 - 18 Sep 2021

Cited by 2 | Viewed by 1711

Abstract

A strip of 20th-century landscape woodland planted alongside a 17th to mid-18th century ancient and semi-natural woodland (ASNW) was investigated by applied aerial spectroscopy using an unmanned aerial vehicle (UAV) with a multispectral image camera (MSI). A simple classification approach of normalized difference [...] Read more.

A strip of 20th-century landscape woodland planted alongside a 17th to mid-18th century ancient and semi-natural woodland (ASNW) was investigated by applied aerial spectroscopy using an unmanned aerial vehicle (UAV) with a multispectral image camera (MSI). A simple classification approach of normalized difference spectral index (NDSI), derived using principal component analysis (PCA), enabled the identification of the non-native trees within the 20th-century boundary. The tree species within this boundary, classified by NDSI, were further segmented by the machine learning segmentation method of k-means clustering. This combined innovative approach has enabled the identification of multiple tree species in the 20th-century boundary. Phenotyping of trees at canopy level using the UAV with MSI, across 8052 m², identified black pine (23%), Norway maple (19%), Scots pine (12%), and sycamore (19%) as well as native trees (oak and silver birch, 27%). This derived data was corroborated by field identification at ground-level, over an area of 6785 m², that confirmed the presence of black pine (26%), Norway maple (30%), Scots pine (10%), and sycamore (14%) as well as other trees (oak and silver birch, 20%). The benefits of using a UAV, with an MSI camera, for monitoring tree boundaries next to a new housing development are demonstrated. Full article

(This article belongs to the Section Environmental Separations)

► Show Figures

Figure 1

12 pages, 1553 KiB

Open AccessCommunication

Preparation of Hydroxytyrosol by Acid Hydrolysis from Olive Leaves

by Yujie Wang, Siyuan Luo, Jieling Luo, Jipeng Qu, Shiling Feng, Tao Chen, Lijun Zhou, Ming Yuan, Hongyu Yang, Tian Li, Bo Lan and Chunbang Ding

Separations 2021, 8(9), 159; https://doi.org/10.3390/separations8090159 - 17 Sep 2021

Cited by 2 | Viewed by 1805

Abstract

Hydroxytyrosol (HT) is the main bioactive compound in olive leaves. However, olive leaves contain a lower level of HT and the extraction process of HT was rarely optimized. In this study, compared with two extraction methods, ultrasound was found to have a positive [...] Read more.

Hydroxytyrosol (HT) is the main bioactive compound in olive leaves. However, olive leaves contain a lower level of HT and the extraction process of HT was rarely optimized. In this study, compared with two extraction methods, ultrasound was found to have a positive effect on improving the yield of HT. Therefore, ultrasound was used to assist hydrolysis of hydrochloric acid to extract HT from olive leaves. Response surface method and macroporous resins were applied to optimize the extraction process as well as enrichment of HT. The results showed that ultrasonic extraction time had a significant effect on the yield and the optimal extraction conditions were obtained: ultrasonic time was 120 min, hydrochloric acid concentration was 1.60 mol/L and the liquid-to-material ratio was 60.00 mL/g. Under the optimal extraction condition, the yield of HT was 14.11 ± 0.12 mg/g. NKA-Ⅱ macroporous resin was proved to be a suitable resin to enrich HT from extraction solution. The optimal condition for enriching HY was 250 mL of loading solution at the flow rate of 1.5 mL/min with 40 mL volume of 75% ethanol–eluent at a flow rate of 1.0 mL/min. The concentration of HT changed from 2.27% to 9.25% after enrichment by macroporous resin. Full article

(This article belongs to the Special Issue Advance of Separation and Purification Technology in Biotechnology and Biochemistry Macromolecule)

► Show Figures

Graphical abstract

16 pages, 861 KiB

Open AccessReview

Currently Applied Extraction Processes for Secondary Metabolites from Lippia turbinata and Turnera diffusa and Future Perspectives

by Guillermo C. G. Martínez-Ávila, Pedro Aguilar-Zarate and Romeo Rojas

Separations 2021, 8(9), 158; https://doi.org/10.3390/separations8090158 - 17 Sep 2021

Cited by 5 | Viewed by 3238

Abstract

The poleo (Lippia turbinata Griseb.) and damiana (Turnera diffusa Wild) are two of the most valued species in the Mexican semidesert due to their medicinal uses. The conventional essential oil extraction process is hydrodistillation, and for the extraction of antioxidants, the [...] Read more.

The poleo (Lippia turbinata Griseb.) and damiana (Turnera diffusa Wild) are two of the most valued species in the Mexican semidesert due to their medicinal uses. The conventional essential oil extraction process is hydrodistillation, and for the extraction of antioxidants, the use of organic solvents. However, these techniques are time-consuming and degrade thermolabile molecules, and the efficiency of the process is dependent on the affinity of the solvent for bioactive compounds. Likewise, they generate solvent residues such as methanol, hexane, petroleum ether, toluene, chloroform, etc. Therefore, in recent years, ecofriendly alternatives such as ohmic heating, microwaves, ultrasound, and supercritical fluids have been studied. These methodologies allow reducing the environmental impact and processing times, in addition to increasing yields at a lower cost. Currently, there is no up-to-date information that provides a description of the ecofriendly trends for the recovery process of essential oils and antioxidants from Lippia turbinata and Turnera diffusa. This review includes relevant information on the most recent advancements in these processes, including conditions and methodological foundation. Full article

(This article belongs to the Special Issue Advance of Separation and Purification Technology in Biotechnology and Biochemistry Macromolecule)

► Show Figures

Figure 1

14 pages, 1022 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Analysis of Volatiles in Food Products

by Małgorzata Starowicz

Separations 2021, 8(9), 157; https://doi.org/10.3390/separations8090157 - 17 Sep 2021

Cited by 29 | Viewed by 7548

Abstract

The evaluation of volatiles in food is an important aspect of food production. It gives knowledge about the quality of foods and their relationship to consumers’ choices. Alcohols, aldehydes, acids, esters, terpenes, pyrazines, and furans are the main chemical groups that are involved [...] Read more.

The evaluation of volatiles in food is an important aspect of food production. It gives knowledge about the quality of foods and their relationship to consumers’ choices. Alcohols, aldehydes, acids, esters, terpenes, pyrazines, and furans are the main chemical groups that are involved in aroma formation. They are products of food processing: thermal treatment, fermentation, storage, etc. Food aroma is a mixture of varied molecules. Because of this, the analysis of aroma composition can be challenging. The four main steps can be distinguished in the evaluation of the volatiles in the food matrix as follows: (1) isolation and concentration; (2) separation; (3) identification; and (4) sensory characterization. The most commonly used techniques to separate a fraction of volatiles from non-volatiles are solid-phase micro-(SPME) and stir bar sorptive extractions (SBSE). However, to study the active components of food aroma by gas chromatography with olfactometry detector (GC-O), solvent-assisted flavor evaporation (SAFE) is used. The volatiles are mostly separated on GC systems (GC or comprehensive two-dimensional GCxGC) with the support of mass spectrometry (MS, MS/MS, ToF–MS) for chemical compound identification. Besides omics techniques, the promising part could be a study of aroma using electronic nose. Therefore, the main assumptions of volatolomics are here described. Full article

(This article belongs to the Section Analysis of Food and Beverages)

► Show Figures

Graphical abstract

10 pages, 751 KiB

Open AccessArticle

Comparison of Phenolic Compounds in Olive Leaves by Different Drying and Storage Methods

by Shiling Feng, Chunyan Zhang, Li Liu, Zhou Xu, Tao Chen, Lijun Zhou, Ming Yuan, Tian Li and Chunbang Ding

Separations 2021, 8(9), 156; https://doi.org/10.3390/separations8090156 - 17 Sep 2021

Cited by 11 | Viewed by 1753

Abstract

Oleuropein, a bitter substance that exists in olive leaves, can be hydrolyzed to hydroxytyrosol. These are the main phenolic compounds, and they have beneficial properties to human bodies. In this study, we established a simple and new method to determine oleuropein and hydroxytyrosol [...] Read more.

Oleuropein, a bitter substance that exists in olive leaves, can be hydrolyzed to hydroxytyrosol. These are the main phenolic compounds, and they have beneficial properties to human bodies. In this study, we established a simple and new method to determine oleuropein and hydroxytyrosol quickly by HPLC. HPLC conditions were set as follows: water (A) acetonitrile (B) as mobile phase, gradient elution orders: 90%A–10%B for 0–10 min, 80%A–20%B for 14–30 min, and then change to 90%A–10%B for 30–33 min; detection wavelength: 280 nm. Compared with other detection methods, the method simplified the elution procedure and shortened the time. Additionally, we provided a better drying method and preservation of olive leaves in tea drinking production that were air-dried at room temperature of 25 °C. Full article

(This article belongs to the Special Issue Analytical Methods and Application of Separation Techniques in Food Science)

► Show Figures

Figure 1

19 pages, 3017 KiB

Open AccessArticle

Maximizing Contents of Phytochemicals Obtained from Dried Sour Cherries by Ultrasound-Assisted Extraction

by Anita Milić, Tatjana Daničić, Aleksandra Tepić Horecki, Zdravko Šumić, Danijela Bursać Kovačević, Predrag Putnik and Branimir Pavlić

Separations 2021, 8(9), 155; https://doi.org/10.3390/separations8090155 - 16 Sep 2021

Cited by 7 | Viewed by 2161

Abstract

Sour cherries were first dried by vacuum drying and then used as material for obtaining extracts rich in bioactive compounds by ultrasound-assisted extraction (UAE). The first step was to apply a factorial design for the preliminary experiments to determine the most influential UAE [...] Read more.

Sour cherries were first dried by vacuum drying and then used as material for obtaining extracts rich in bioactive compounds by ultrasound-assisted extraction (UAE). The first step was to apply a factorial design for the preliminary experiments to determine the most influential UAE factors, and thus the three studied parameters were chosen as the most suitable for the design of the main experiment (temperature, liquid–solid ratio and ethanol concentration). In this part, the contents of total phenols and the total content of monomeric anthocyanins were taken for responses. For the further optimization of UAE, experimental design (face-centered) was applied, and the yield, total phenolics, flavonoid content and content of monomeric anthocyanins and antioxidant activity (DPPH, ABTS and FRAP assays) were analyzed. Temperature (40–80 °C), ethanol concentration (40–80%, w/w) and liquid–solid ratio (10–30 mL/g) were investigated as independent variables. The obtained experimental results were fitted to a second-order polynomial model and analysis of variance was used to determine the fit of the model and the optimal conditions for investigated responses. High quality extracts with high concentrations of polyphenols and anthocyanins were also obtained, which could be used as food additives. Full article

(This article belongs to the Special Issue Food Quality and Safety: Advances in Analytical Methods and Applications)

► Show Figures

Figure 1

11 pages, 1488 KiB

Open AccessArticle

Effects of Ethanol on the Supercritical Carbon Dioxide Extraction of Cannabinoids from Near Equimolar (THC and CBD Balanced) Cannabis Flower

by Sadia Qamar, Yady J. M. Torres, Harendra S. Parekh and James Robert Falconer

Separations 2021, 8(9), 154; https://doi.org/10.3390/separations8090154 - 15 Sep 2021

Cited by 10 | Viewed by 3656

Abstract

In this study, supercritical carbon dioxide (scCO₂) extractions of cannabinoids were conducted at four different densities (231, 590, 818, and 911 kg/m³) using ethanol (5% w/v) as a co-solvent. The chemical profiles of these cannabinoids were analysed via [...] Read more.

In this study, supercritical carbon dioxide (scCO₂) extractions of cannabinoids were conducted at four different densities (231, 590, 818, and 911 kg/m³) using ethanol (5% w/v) as a co-solvent. The chemical profiles of these cannabinoids were analysed via reverse-phase high-performance liquid chromatography (RP-HPLC). It was determined that scCO₂, at low density (231 kg/m³), produced an extract yield of 6.1% w/v. At high scCO₂ density (~818 kg/m³), the yield was 16.1% w/v. More specifically, the amounts of tetrahydrocannabinol (THC) and cannabidiol (CBD) in the scCO₂ extract at 818 kg/m³ were 10.8 and 15.6% w/v, respectively. It was also found that the use of 5% w/v ethanol increased scCO₂ extract yields at both low and high densities (7.6% w/v and 18.2% w/v, respectively). Additionally, the use of co-solvent increased this yield further under both low- and high-density conditions, to 13.7 and 19.1% w/v, respectively. Interestingly, higher scCO₂ density (911 kg/m³) with and without ethanol did not improve the scCO₂ extract yield or the amount of cannabinoids. Although this study provides new insights into the correlation between scCO₂ density and ethanol co-extraction of CBD and THC, more studies are needed to determine how different scCO₂ densities and co-solvents influence the extraction of cannabinoids. Full article

► Show Figures

Figure 1

29 pages, 2234 KiB

Open AccessEditor’s ChoiceReview

Magnetic Ionic Liquids in Sample Preparation: Recent Advances and Future Trends

by Theodoros Chatzimitakos, Phoebe Anagnostou, Ioanna Constantinou, Kalliroi Dakidi and Constantine Stalikas

Separations 2021, 8(9), 153; https://doi.org/10.3390/separations8090153 - 13 Sep 2021

Cited by 12 | Viewed by 3357

Abstract

In the last decades, a myriad of materials has been synthesized and utilized for the development of sample preparation procedures. The use of their magnetic analogues has gained significant attention and many procedures have been developed using magnetic materials. In this context, the [...] Read more.

In the last decades, a myriad of materials has been synthesized and utilized for the development of sample preparation procedures. The use of their magnetic analogues has gained significant attention and many procedures have been developed using magnetic materials. In this context, the benefits of a new class of magnetic ionic liquids (MILs), as non-conventional solvents, have been reaped in sample preparation procedures. MILs combine the advantageous properties of ionic liquids along with the magnetic properties, creating an unsurpassed combination. Owing to their unique nature and inherent benefits, the number of published reports on sample preparation with MILs is increasing. This fact, along with the many different types of extraction procedures that are developed, suggests that this is a promising field of research. Advances in the field are achieved both by developing new MILs with better properties (showing either stronger response to external magnetic fields or tunable extractive properties) and by developing and/or combining methods, resulting in advanced ones. In this advancing field of research, a good understanding of the existing literature is needed. This review aims to provide a literature update on the current trends of MILs in different modes of sample preparation, along with the current limitations and the prospects of the field. The use of MILs in dispersive liquid–liquid microextraction, single drop microextraction, matrix solid-phase dispersion, etc., is discussed herein among others. Full article

(This article belongs to the Special Issue Development and Application of Green or Sustainable Strategies in Analytical Chemistry)

► Show Figures

Figure 1

19 pages, 1396 KiB

Open AccessEditor’s ChoiceArticle

Development of a Simple High-Performance Liquid Chromatography-Based Method to Quantify Synergistic Compounds and Their Composition in Dried Leaf Extracts of Piper Sarmentosum Roxb.

by Rayudika Aprilia Patindra Purba, Siwaporn Paengkoum and Pramote Paengkoum

Separations 2021, 8(9), 152; https://doi.org/10.3390/separations8090152 - 13 Sep 2021

Cited by 20 | Viewed by 3742

Abstract

There is a growing demand to enhance pharmaceutical and food safety using synergistic compounds from Piper sarmentosum Roxb., such as polyphenols and water-soluble vitamins. However, information on standardized analytical methods to identify and quantify these compounds of interest is limited. A reversed-phase high-performance [...] Read more.

There is a growing demand to enhance pharmaceutical and food safety using synergistic compounds from Piper sarmentosum Roxb., such as polyphenols and water-soluble vitamins. However, information on standardized analytical methods to identify and quantify these compounds of interest is limited. A reversed-phase high-performance liquid chromatography with diode-array detection (HPLC-DAD)-based method was developed to simultaneously detect and quantify the amounts of tannin, flavonoid, cinnamic acid, essential oil, and vitamins extracted from P. sarmentosum leaves using methanol, chloroform, and hexane. Commercially and non-commercially-cultivated P. sarmentosum leaves were subjected to seven different drying treatments (shade; sun; air oven at 40 °C, 60 °C, 80 °C, and 100 °C; and freeze-drying) for three consecutive months. Most compounds were detected most efficiently at a detection wavelength of 272 nm. The developed method displayed good detection limits (LOD, 0.026–0.789 µg/mL; LOQ, 0.078–2.392 µg/mL), linearity (R² > 0.999), precision (%RSD, <1.00), and excellent accuracy (96–102%). All P. sarmentosum leaf extracts were simultaneously tested and analytically compared without time-consuming fractionation. Methanolic plant extracts showed better peak area and retention time splits compared to chloroformic and hexanoic extracts. Differences in synergistic compound composition were dependent on the type of drying treatment but not on cultivation site and time of sampling. Flavonoid was identified as the dominant phytochemical component in P. sarmentosum leaves, followed by the essential oil, cinnamic acid, ascorbic acid, and tannin. Overall, we present a simple and reproducible chromatographic method that can be applied to identify different plant compounds. Full article

(This article belongs to the Special Issue Application of Chromatography and Different Extraction Techniques in Analysis of Polyphenolic Compounds)

► Show Figures

Graphical abstract

17 pages, 2848 KiB

Open AccessArticle

Determination of Formaldehyde Yields in E-Cigarette Aerosols: An Evaluation of the Efficiency of the DNPH Derivatization Method

by Xiaohong C. Jin, Regina M. Ballentine, William P. Gardner, Matt S. Melvin, Yezdi B. Pithawalla, Karl A. Wagner, Karen C. Avery and Mehran Sharifi

Separations 2021, 8(9), 151; https://doi.org/10.3390/separations8090151 - 13 Sep 2021

Cited by 4 | Viewed by 2971

Abstract

Recent reports have suggested that (1) formaldehyde levels (measured as a hydrazone derivative using the DNPH derivatization method) in Electronic Nicotine Delivery Systems (ENDS) products were underreported because formaldehyde may react with propylene glycol (PG) and glycerin (Gly) in the aerosol to form [...] Read more.

Recent reports have suggested that (1) formaldehyde levels (measured as a hydrazone derivative using the DNPH derivatization method) in Electronic Nicotine Delivery Systems (ENDS) products were underreported because formaldehyde may react with propylene glycol (PG) and glycerin (Gly) in the aerosol to form hemiacetals; (2) the equilibrium would shift from the hemiacetals to the acetals in the acidic DNPH trapping solution. In both cases, neither the hemiacetal nor the acetal would react with DNPH to form the target formaldehyde hydrazone, due to the lack of the carbonyl functional group, thus underreporting formaldehyde. These reports were studied in our laboratory. Our results showed that the aerosol generated from formaldehyde-fortified e-liquids provided a near-quantitative recovery of formaldehyde in the aerosol, suggesting that if any hemiacetal was formed in the aerosol, it would readily hydrolyze to free formaldehyde and, consequently, form formaldehyde hydrazone in the acidic DNPH trapping solution. We demonstrated that custom-synthesized Gly and PG hemiacetal adducts added to the DNPH trapping solution would readily hydrolyze to form the formaldehyde hydrazone. We demonstrated that acetals of PG and Gly present in e-liquid are almost completely transferred to the aerosol during aerosolization. The study results demonstrate that the DNPH derivatization method allows for an accurate measurement of formaldehyde in vapor products. Full article

(This article belongs to the Special Issue Method Development and Applications for Reduced-Risk Products in Separation Science)

► Show Figures

Figure 1

13 pages, 693 KiB

Open AccessArticle

Developing a Fast Ultra-High-Performance Liquid Chromatography–Tandem Mass Spectrometry Method for High-Throughput Surface Contamination Monitoring of 26 Antineoplastic Drugs

by Stefano Dugheri, Nicola Mucci, Donato Squillaci, Giorgio Marrubini, Gianluca Bartolucci, Camillo Melzi, Elisabetta Bucaletti, Giovanni Cappelli, Lucia Trevisani and Giulio Arcangeli

Separations 2021, 8(9), 150; https://doi.org/10.3390/separations8090150 - 10 Sep 2021

Cited by 4 | Viewed by 1968

Abstract

Growing attention on carcinogenicity and mutagenicity of antineoplastic drugs (ADs) from the International Agencies has led to the present strict safe handling and administration regulations. Accordingly, one of the most common ways to assess occupational exposure to these substances is to identify and [...] Read more.

Growing attention on carcinogenicity and mutagenicity of antineoplastic drugs (ADs) from the International Agencies has led to the present strict safe handling and administration regulations. Accordingly, one of the most common ways to assess occupational exposure to these substances is to identify and quantify possible surface contamination inside hospital preparation and administration units. Thus, it is essential to develop a fast and high-throughput monitoring method capable of identifying a significant number of ADs. The present study reports developing a UHPLC–MS/MS analysis to screen 26 ADs surface contamination through wipe test sampling. A Cortecs UPLC T3 50 × 2.1 mm (1.6 µm) column was selected to perform the analysis, using the evaluations of previous studies and the Product Quality Research Institute (PQRI) database. The design of experiments (DoE) methodological approach was used to optimize the chromatographic conditions concerning the best separation between all ADs. The limits of quantification for the analytes were between the pg/mL and ng/mL orders, and the turnaround time was limited to about 15 min. The obtained accuracy was mostly between 90% and 110% for all the analytes, while the precision was under 10% and a low matrix effect was observed for said analytes. Only vindesine and docetaxel presented lower performances. Full article

(This article belongs to the Section Chromatographic Separations)

► Show Figures

Figure 1

9 pages, 1088 KiB

Open AccessArticle

Luminol Doped Silica-Polymer Sensor for Portable Organic Amino Nitrogen and Ammonium Determination in Water

by Sara Bocanegra-Rodríguez, Carmen Molins-Legua and Pilar Campíns-Falcó

Separations 2021, 8(9), 149; https://doi.org/10.3390/separations8090149 - 10 Sep 2021

Cited by 1 | Viewed by 1843

Abstract

We propose a portable sensor, obtained by embedding luminol into the tetraethylorthosilicate/trietoxymethylsilane (TEOS/MTEOS) composite, for the quantitative determination of organic amino nitrogen and ammonium in water with the goal of achieving low levels of concentration. The method is based on the reaction between [...] Read more.

We propose a portable sensor, obtained by embedding luminol into the tetraethylorthosilicate/trietoxymethylsilane (TEOS/MTEOS) composite, for the quantitative determination of organic amino nitrogen and ammonium in water with the goal of achieving low levels of concentration. The method is based on the reaction between amino nitrogen compounds and hypochlorite to produce chloramino derivatives. Then, the remaining hypochlorite reacts with luminol sensor by producing a luminescence signal, which was measured by using a portable luminometer, being inversely proportional to nitrogen concentration. The liberation of the luminol from sensor is higher than 90% and the sensor is stable for at least a week at room temperature. This portable method was successfully validated and applied to the analysis of several real waters: fountain, river transition, lagoon, and seawater with recovery values between 92% and 112%, which indicated that the matrix effect was absent. The achieved limit of detection was around 10 µg·L⁻¹, expressed as N. This sensor allows in situ monitoring owing to its simplicity, rapidity, and portability. Full article

(This article belongs to the Section Materials in Separation Science)

► Show Figures

Figure 1

10 pages, 10785 KiB

Open AccessArticle

Survey on Antibiotic Residues in Egg Samples in Italy

by Giorgio Saluti, Maria Novella Colagrande, Federica Castellani, Matteo Ricci, Gianfranco Diletti and Giampiero Scortichini

Separations 2021, 8(9), 148; https://doi.org/10.3390/separations8090148 - 09 Sep 2021

Cited by 2 | Viewed by 2159

Abstract

The presence of antibiotic residue in eggs is a current issue due to the increasingly important phenomenon of antibiotic resistance. A multiclass, confirmatory method for the determination of seventy-three antimicrobial agents (amphenicols, cephalosporins, diaminopyrimidines, lincosamides, macrolides, penicillins, pleuromutilins, quinolones, sulfonamides, and tetracyclines) with [...] Read more.

The presence of antibiotic residue in eggs is a current issue due to the increasingly important phenomenon of antibiotic resistance. A multiclass, confirmatory method for the determination of seventy-three antimicrobial agents (amphenicols, cephalosporins, diaminopyrimidines, lincosamides, macrolides, penicillins, pleuromutilins, quinolones, sulfonamides, and tetracyclines) with liquid chromatography high-resolution mass spectrometry was applied to 200 egg samples collected from 119 Italian farms during the years 2018–2021. Full article

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

► Show Figures

Figure 1

11 pages, 3334 KiB

Open AccessArticle

Simultaneous Separation and Analysis of Five Compounds in Cibotium barometz by Micellar Electrokinetic Chromatography with Large-Volume Sample Stacking

by Lili Wang, Huifeng Xu, Lishuang Yu, Zaishi Zhu, Hongzhi Ye, Linglong Liu, Xihai Li and Jun Peng

Separations 2021, 8(9), 147; https://doi.org/10.3390/separations8090147 - 07 Sep 2021

Cited by 4 | Viewed by 1821

Abstract

A large volume sample stacking (LVSS) method in micellar electrokinetic chromatography (MEKC) with diode array detector was developed for the simultaneous separation and analysis of five compounds: protocatechuic acid, protocatechuic aldehyde, caffeic acid, syringetin and vanillin in Cibotium barometz. The electrophoretic separation [...] Read more.

A large volume sample stacking (LVSS) method in micellar electrokinetic chromatography (MEKC) with diode array detector was developed for the simultaneous separation and analysis of five compounds: protocatechuic acid, protocatechuic aldehyde, caffeic acid, syringetin and vanillin in Cibotium barometz. The electrophoretic separation was performed in a 10 mM sodium dodecyl sulfate (SDS) and 50 mM sodium borax-sodium dihydrogen phosphate system (pH = 8.5) with 10% methanol at a separation voltage of 30 kV after optimizing the typical parameters. The detection limits were from 32 pg to 65 pg, which were around 12–27 times lower than MEKC, and 500 times less than reported methods. Finally, the established method was validated to be applicable for the determination of protocatechuic acid and caffeic acid in Cibotium barometz. This proposed method is expected to facilitate the quality control of Cibotium barometz. Full article

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

► Show Figures

Graphical abstract

14 pages, 1471 KiB

Open AccessArticle

Eco-Friendly UPLC-MS/MS Quantitation of Delafloxacin in Plasma and Its Application in a Pharmacokinetic Study in Rats

by Muzaffar Iqbal, Essam Ezzeldin, Md. Khalid Anwer and Faisal Imam

Separations 2021, 8(9), 146; https://doi.org/10.3390/separations8090146 - 06 Sep 2021

Cited by 6 | Viewed by 2095

Abstract

A novel UPLC-MS/MS assay was developed for rapid quantification of delafloxacin (a novel fluoroquinolone antibiotic in plasma samples by one step sample cleanup procedure. Delafloxacin (DFX) and internal standard (losartan) were separated on a UPLC BEH C₁₈ column (50 × 2.1 mm; [...] Read more.

A novel UPLC-MS/MS assay was developed for rapid quantification of delafloxacin (a novel fluoroquinolone antibiotic in plasma samples by one step sample cleanup procedure. Delafloxacin (DFX) and internal standard (losartan) were separated on a UPLC BEH C₁₈ column (50 × 2.1 mm; 1.7 μm) by using gradient programing of a mobile phase containing 0.1% formic acid in acetonitrile and 0.1% formic acid in water. The quantification was performed by a using triple-quadrupole mass detector at an electrospray ionization interface in positive mode. The precursor to the product ion transition of 441.1 → 379.1 for the qualifier and 441.1 → 423.1 for the quantifier was used for DFX monitoring, whereas 423.1 → 207.1 was used for the internal standard. The validation was performed as per guidelines of bioanalytical method validation, and the evaluated parameters were within the acceptable range. The greenness assessment of the method was evaluated by using AGREE software covering all 12 principles of green analytical chemistry. The final score obtained was 0.78, suggesting excellent greenness of the method. Moreover, Deming regression analysis showed an excellent linear relationship between this method and our previously reported method, and it is suitable for high-throughput analysis for routine application. The proposed method was effectively applied in a pharmacokinetic study of novel formulation (self-nanoemulsifying drug delivery systems) of DFX in rats. Full article

(This article belongs to the Special Issue Current Trends in Chromatography for Bioanalytical Applications)

► Show Figures

Graphical abstract

7 pages, 210 KiB

Open AccessReview

Dried Blood Spot in Toxicology: Current Knowledge

by Agnieszka Niemiec

Separations 2021, 8(9), 145; https://doi.org/10.3390/separations8090145 - 06 Sep 2021

Cited by 3 | Viewed by 3116

Abstract

Dried Blood Spot (DBS) is becoming very popular in various medical fields, especially in toxicology. Nowadays it is commonly used in newborn screening for inherited or congenital diseases. This paperwork is based on a review of available literature. DBS is simple and rapid, [...] Read more.

Dried Blood Spot (DBS) is becoming very popular in various medical fields, especially in toxicology. Nowadays it is commonly used in newborn screening for inherited or congenital diseases. This paperwork is based on a review of available literature. DBS is simple and rapid, it does not require trained medical staff to collect the samples. Specimens can be easily and safely transported to the laboratory. DBS provides an opportunity for roadside testing and rather quick results. Venous blood spot, collected from a finger or a heel, is put on the special paper card, which can result in a different distribution of blood and concentration of detecting substances. Marking multiple substances from one spot is extremely challenging, but due to further advancements in this area, it is only a matter of time until it becomes possible and all the disadvantages vanish. DBS is certain to develop and become even more worldwide used. Full article

(This article belongs to the Section Bioanalysis/Clinical Analysis)

14 pages, 1245 KiB

Open AccessArticle

Quality Assessment of Camellia oleifera Oil Cultivated in Southwest China

by Li Liu, Shiling Feng, Tao Chen, Lijun Zhou, Ming Yuan, Jinqiu Liao, Yan Huang, Hongyu Yang, Ruiwu Yang and Chunbang Ding

Separations 2021, 8(9), 144; https://doi.org/10.3390/separations8090144 - 05 Sep 2021

Cited by 13 | Viewed by 2833

Abstract

Camellia oleifera oil has attracted increasing attention due to its well-balanced composition. In this study, we evaluated the oil content and chemical composition of C. oleifera oil cultivated in southwest China. The results showed that the acid and peroxide values were in line [...] Read more.

Camellia oleifera oil has attracted increasing attention due to its well-balanced composition. In this study, we evaluated the oil content and chemical composition of C. oleifera oil cultivated in southwest China. The results showed that the acid and peroxide values were in line with the optimal quality index of the national standard of China. Oleic acid was the most predominant and important fatty acid, which accounted for 80.34–86.18%. The α-tocopherol, polyphenols and squalene ranged from 112.36 to 410.46 mg/kg oil, 14.22 to 53.63 mg/kg oil and 14.80 to 52.49 mg/kg oil, respectively. Principal component analysis (PCA) results showed that the synthesis score of introduced cultivars (‘Changlin 3’, ‘Changlin 4’ and ‘Changlin 18’) was higher that the local cultivars (‘Chuanya 21’ and ‘Chuanlin 2’). This research demonstrated that the introduced C. oleifera could adapt to the environment and climate of southwest China and large-scale plant of these introduced cultivars. In addition, the C. oleifera oil rich in unsaturated fatty acid has enormous potential to become a kind of functional oil and possesses great prospects for pharmaceutical and industrial applications. Full article

(This article belongs to the Special Issue Advance of Separation and Purification Technology in Biotechnology and Biochemistry Macromolecule)

► Show Figures

Figure 1

12 pages, 282 KiB

Open AccessEditor’s ChoiceArticle

Analysis of Selected Mycotoxins in Maize from North-West South Africa Using High Performance Liquid Chromatography (HPLC) and Other Analytical Techniques

by Theodora Ijeoma Ekwomadu, Toluwase Adeseye Dada, Stephen Abiola Akinola, Nancy Nleya and Mulunda Mwanza

Separations 2021, 8(9), 143; https://doi.org/10.3390/separations8090143 - 03 Sep 2021

Cited by 17 | Viewed by 2541

Abstract

Contamination of foods by mycotoxins is linked to various health and economic implications. This study evaluated the incidence of mycotoxins in commercial and small-scale maize and evaluated potential health risks for consumers based on South African and international regulations. The sensitivity/specificity of HPLC [...] Read more.

Contamination of foods by mycotoxins is linked to various health and economic implications. This study evaluated the incidence of mycotoxins in commercial and small-scale maize and evaluated potential health risks for consumers based on South African and international regulations. The sensitivity/specificity of HPLC over other analytical methods used was also ascertained. In total, 100 maize samples were analyzed using immuno-affinity column for extraction and clean-up, thin layer chromatography (TLC), HPLC, and enzyme linked immunosorbent assay (ELISA) for quantification. Results revealed that fumonisinB₁ was the most contaminant mycotoxin in both small-scale and commercial samples with incidence rates of 100% and 98.6%, respectively. Aflatoxins contamination occurred at incidences of 26.7% in small-scale and 25.0% in commercial samples. Furthermore, ochratoxin A had high incidence rates of 97.8% and 93.0% and ranged from 3.60–19.44 µg/kg and 1.60–9.89 µg/kg, respectively, in small-scale and commercial samples, while ZEA occurred in 50% and 55% of small-scale and commercial samples, respectively. Results demonstrate that maize, especially from small-scale farmers, may contribute to dietary exposure to mycotoxins. Farmers and consumers should be alerted to the dangers of mycotoxins contamination in maize with resultant health risks. Additionally, HPLC method was also found to be more specific for mycotoxin detection than ELISA. Full article

(This article belongs to the Special Issue HPLC: A Key Tool for Analytical Chemistry)

12 pages, 3777 KiB

Open AccessFeature PaperArticle

Red Blood Cell Metabolism in Patients with Propionic Acidemia

by Micaela Kalani Roy, Francesca Isabelle Cendali, Gabrielle Ooyama, Fabia Gamboni, Holmes Morton and Angelo D’Alessandro

Separations 2021, 8(9), 142; https://doi.org/10.3390/separations8090142 - 03 Sep 2021

Cited by 2 | Viewed by 2313

Abstract

Propionic acidemia (PA) is a rare autosomal recessive disorder with an estimated incidence of 1:100,000 live births in the general population. Due in part to an insufficient understanding of the disease’s pathophysiology, PA is often associated with complications, and in severe cases can [...] Read more.

Propionic acidemia (PA) is a rare autosomal recessive disorder with an estimated incidence of 1:100,000 live births in the general population. Due in part to an insufficient understanding of the disease’s pathophysiology, PA is often associated with complications, and in severe cases can cause coma and death. Despite its association with hematologic disorders, PA’s effect on red blood cell metabolism has not been described. Mass spectrometry-based metabolomics analyses were performed on RBCs from healthy controls (n = 10) and PKD patients (n = 3). PA was associated with a significant decrease in the steady state level of glycolytic products and the apparent activation of the PPP. The PA samples showed decreases in succinate and increases in the downstream dicarboxylates of the TCA cycle. BCAAs were lowered in the PA samples and C3 carnitine, a direct metabolite of propionic acid, was increased. Trends in the markers of oxidative stress including hypoxanthine, allantoate and spermidine were the opposite of those associated with elevated ROS burden. The alteration of short chain fatty acids, the accumulation of some medium chain and long chain fatty acids, and decreased markers of lipid peroxidation in the PA samples contrasted with previous research. Despite limitations from a small cohort, this study provides the first investigation of RBC metabolism in PA, paving the way for targeted investigations of the critical pathways found to be dysregulated in the context of this disease. Full article

► Show Figures

Graphical abstract

9 pages, 918 KiB

Open AccessArticle

Determination of Tedizolid in Bacterial Growth Medium Mueller-Hinton Broth by High-Performance Liquid Chromatography and Its Application to an In Vitro Study in the Hollow-Fiber Infection Model

by Khalid Iqbal, Aliki Milioudi, Elena Haro Martínez and Sebastian Georg Wicha

Separations 2021, 8(9), 141; https://doi.org/10.3390/separations8090141 - 02 Sep 2021

Cited by 1 | Viewed by 2410

Abstract

Pharmacokinetic/pharmacodynamic (PKPD) studies of anti-infectives are frequently performed in in vitro infection models where accurate quantification of antibiotic concentrations in bacterial growth media is crucial to establish PK/PD relationships. Here, a sensitive and rapid high-performance liquid chromatography (HPLC) method was developed to quantify [...] Read more.

Pharmacokinetic/pharmacodynamic (PKPD) studies of anti-infectives are frequently performed in in vitro infection models where accurate quantification of antibiotic concentrations in bacterial growth media is crucial to establish PK/PD relationships. Here, a sensitive and rapid high-performance liquid chromatography (HPLC) method was developed to quantify tedizolid (TDZ) in the bacterial growth medium Mueller-Hinton broth (MHB). Matrix components were separated by direct protein precipitation with methanol (1:1). The chromatographic separation was carried out in a Dionex Ultimate 3000 HPLC system using an Accucore^® C-18 RPMS HPLC column (2.6 µm, 100 × 2.1 mm) using isocratic elution with 25% acetonitrile and 75% of 0.1% formic acid. The lower limit of quantification was 0.03 mg/L when measured at 300 nm. Following relevant European Medicine Agency guidelines, the method was successfully validated for linearity, selectivity, recovery, inter- and intra-day precision, and accuracy and stability. When applied to in vitro PKPD studies, the method successfully quantified a range of TDZ concentration (Cmin, 0.09-Cmax, 0.65 mg/L) in MHB. The analyzed concentrations were in line with the planned PK profiles. The application of the developed method to quantify TDZ in MHB in in vitro PKPD studies is warranted. Full article

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

► Show Figures

Graphical abstract

16 pages, 4483 KiB

Open AccessArticle

Use of Thermally Assisted Hydrolysis and Methylation (THM-GC-MS) to Unravel Influence of Pottery Production and Post-Depositional Processes on the Molecular Composition of Organic Matter in Sherds from a Complex Coastal Settlement

by Joeri Kaal, María Guadalupe Castro González, Antonio Martínez Cortizas and María Pilar Prieto Martínez

Separations 2021, 8(9), 140; https://doi.org/10.3390/separations8090140 - 01 Sep 2021

Cited by 2 | Viewed by 1949

Abstract

Ceramic fragments from the Islet of Guidoiro Areoso (NW Spain), covering a wide range of cultural periods (Neolithic to Late Bronze Age), have been studied by color analysis, elemental analysis of carbon (C) and nitrogen (N), and molecular analysis (thermally assisted hydrolysis and [...] Read more.

Ceramic fragments from the Islet of Guidoiro Areoso (NW Spain), covering a wide range of cultural periods (Neolithic to Late Bronze Age), have been studied by color analysis, elemental analysis of carbon (C) and nitrogen (N), and molecular analysis (thermally assisted hydrolysis and methylation, THM-GC-MS), in order to identify the organic matter (OM) in the prehistoric pottery and reveal information on ceramic production techniques, food remains and post-depositional effects. Results showed that the strong marine influence (sherds recovered from coastal deposits) and microbial activity (recovery from waste deposits, “cuncheiros”) had a profound effect on C/N ratio and molecular composition (N-rich protein and chitin structures). Other organic ingredients originated from the material used for creating the ware (detected as pyrogenic OM) and possibly food remains (fatty acid fingerprints). Dark-colored ware was enriched in both pyrogenic OM from incomplete combustion and non-bacterial fatty acids. Fatty acid patterns could not be related to possible vessel use, and markers of aquatic resources were scarce, or absent. It is argued that THM-GC-MS of pottery fragments is useful for understanding how an archaeological deposit developed in time, what kinds of OM are present, and possibly to make a pre-selection of samples with high potential for more cost-demanding dietary molecular assessments. Full article

(This article belongs to the Special Issue Analytical Chromatography Applied to Archaeology)

► Show Figures

Figure 1

15 pages, 1305 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Selective Extraction of Platinum(IV) from the Simulated Secondary Resources Using Simple Secondary Amide and Urea Extractants

by Yuki Ueda, Shintaro Morisada, Hidetaka Kawakita and Keisuke Ohto

Separations 2021, 8(9), 139; https://doi.org/10.3390/separations8090139 - 01 Sep 2021

Cited by 10 | Viewed by 2309

Abstract

The recycling of rare metals such as platinum (Pt) from secondary resources, such as waste electronic and electrical equipment and automotive catalysts, is an urgent global issue. In this study, simple secondary amides and urea, N-(2-ethylhexyl)acetamide, N-(2-ethylhexyl)octanamide, and 1-butyl-3-(2-ethylhexyl)urea, which selectively [...] Read more.

The recycling of rare metals such as platinum (Pt) from secondary resources, such as waste electronic and electrical equipment and automotive catalysts, is an urgent global issue. In this study, simple secondary amides and urea, N-(2-ethylhexyl)acetamide, N-(2-ethylhexyl)octanamide, and 1-butyl-3-(2-ethylhexyl)urea, which selectively extract Pt(IV) from a simulated effluent containing numerous metal ions, such as in an actual hydrometallurgical process, were synthesized and achieved efficient Pt(IV) stripping using only water. Comparison of Pt(IV) extraction behavior with a tertiary amide without N–H moieties suggests that the secondary amides and urea extractants effectively use hydrogen bonding to the hexachloroplatinate anion by N–H moieties. Examining the conditions for the third phase formation revealed that the secondary amide extractant with the longest alkyl chain can be used in the extraction process for a long time without forming any third phase, despite its lower Pt(IV) extraction capacity. The practical trial with simple compounds developed in this study should contribute to the development of Pt separation and purification processes. Full article

(This article belongs to the Section Analysis of Energies)

► Show Figures

Graphical abstract

9 pages, 2347 KiB

Open AccessArticle

Improvement of Cucurbitacin B Content in Cucumis melo Pedicel Extracts by Biotransformation Using Recombinant β-Glucosidase

by Jianfeng Mei, Xia Wu, Sujing Zheng, Xiang Chen, Zhuliang Huang and Yichun Wu

Separations 2021, 8(9), 138; https://doi.org/10.3390/separations8090138 - 01 Sep 2021

Cited by 1 | Viewed by 1952

Abstract

For the efficient biotransformation of cucurbitacin B 2-o-β-d-glucoside (CuBg) to cucurbitacin B (CuB) in Cucumis melo pedicel extracts, the β-glucosidase gene bglS—consisting of 1344 bp (447 amino acids) from Streptomyces sp. RW-2—was cloned and expressed in Escherichia coli [...] Read more.

For the efficient biotransformation of cucurbitacin B 2-o-β-d-glucoside (CuBg) to cucurbitacin B (CuB) in Cucumis melo pedicel extracts, the β-glucosidase gene bglS—consisting of 1344 bp (447 amino acids) from Streptomyces sp. RW-2—was cloned and expressed in Escherichia coli BL21(DE3). The activity of recombinant β-glucosidase with p-nitrophenyl-β-d-glucoside (pNPG) as a substrate was 3.48 U/mL in a culture. Using the recombinant β-glucosidase for the biotransformation of C. melo pedicel extracts, CuBg was converted into CuB with a conversion rate of 87.6% when the concentration of CuBg was 0.973 g/L in a reaction mixtures. The concentration of CuB in C. melo pedicel extracts was improved from 13.6 to 20.2 g/L after biotransformation. The present study provides high-efficiency technology for the production of CuB from its glycoside by biotransformation. Full article

(This article belongs to the Collection Recent Trends in the Separation of Natural Products and Pharmaceuticals)

► Show Figures

Graphical abstract

13 pages, 2386 KiB

Open AccessEditor’s ChoiceArticle

Development of Green and Efficient Extraction Methods of Quercetin from Red Onion Scales Wastes Using Factorial Design for Method Optimization: A Comparative Study

by Heba-Alla H. Abd-ElSalam, Mohammed Gamal, Ibrahim A. Naguib, Medhat A. Al-Ghobashy, Hala E. Zaazaa and M. Abdelkawy

Separations 2021, 8(9), 137; https://doi.org/10.3390/separations8090137 - 29 Aug 2021

Cited by 22 | Viewed by 5066

Abstract

Waste resulting from edible plants is considered one of the best sources of valuable phytochemicals. A promising approach for using these appreciated wastes is extracting precious medically important constituents, for example, free quercetin. Two new cost-effective and green extraction methods are introduced in [...] Read more.

Waste resulting from edible plants is considered one of the best sources of valuable phytochemicals. A promising approach for using these appreciated wastes is extracting precious medically important constituents, for example, free quercetin. Two new cost-effective and green extraction methods are introduced in the present study: ultrasound-assisted glycerol extraction (UAGE) and microwave-assisted extraction (MAE). These extraction protocols are optimized using factorial design to define the highest yield of extraction, and HPLC-UV at 370 nm was used as a method of yield analysis. Quercetin remained stable during the whole process in both extraction protocols. A standard addition technique was performed to quantify quercetin in different extracts and eliminate the matrix effect. In UAGE and MAE, extraction yields were 16.55 ± 0.81 and 27.20 ± 1.55 mg/1g from red onion scales on a dry base, respectively. The amount of quercetin extracted using MAE was superior to UAGE in terms of time and yield. A greenness assessment of the offered studies compared to previously published relevant extraction methods was performed using the analytical eco-scale assessment method (ESA) and national environmental methods index (NEMI). MAE showed to be a greener method with a higher ESA score and a greener NEMI pictogram. Full article

► Show Figures

Graphical abstract

14 pages, 3453 KiB

Open AccessArticle

Gas Chromatography-Mass Spectrometry Analysis of Compounds Emitted by Pepper Yellow Leaf Curl Virus-Infected Chili Plants: A Preliminary Study

by Dyah K. Agustika, Ixora S. Mercuriani, Nur Aeni Ariyanti, Chandra W. Purnomo, Kuwat Triyana, Daciana D. Iliescu and Mark S. Leeson

Separations 2021, 8(9), 136; https://doi.org/10.3390/separations8090136 - 27 Aug 2021

Cited by 10 | Viewed by 4129

Abstract

Pepper yellow leaf curl virus (PYLCV) is a threat to chili plants and can significantly reduce yields. This study aimed as a pilot project to detect PYLCV by analyzing compounds emitted by chili plants using gas chromatography-mass spectrometry (GC-MS). The samples investigated in [...] Read more.

Pepper yellow leaf curl virus (PYLCV) is a threat to chili plants and can significantly reduce yields. This study aimed as a pilot project to detect PYLCV by analyzing compounds emitted by chili plants using gas chromatography-mass spectrometry (GC-MS). The samples investigated in this research were PYLCV-infected and PYLCV-undetected chili plants taken from commercial chili fields. The infection status was validated by using a polymerase chain reaction (PCR) test. A headspace technique was used to extract the volatile organic compounds emitted by plants. The analysis of GC-MS results began with pre-processing, analyzing sample compound variability with a boxplot analysis, and sample classification by using a multivariate technique. Unsupervised multivariate technique principal component analysis (PCA) was performed to discover whether GC-MS could identify PYLCV-infected or not. The results showed that PYLCV-infected and PYLCV-undetected chili plants could be differentiated, with a total percent variance of the first three principal components reaching 91.32%, and successfully discriminated between PYLCV-infected and PYLCV-undetected chili plants. However, more comprehensive studies are needed to find the potential biomarkers of the infected plants. Full article

(This article belongs to the Special Issue Comprehensive Separations of Complex Mixtures by Gas Chromatography/Mass Spectrometry)

► Show Figures

Figure 1

11 pages, 1016 KiB

Open AccessArticle

A Simple Microextraction Method for Toxic Industrial Dyes Using a Fatty-Acid Solvent Mixture

by Danielle P. Arcon and Francisco C. Franco

Separations 2021, 8(9), 135; https://doi.org/10.3390/separations8090135 - 26 Aug 2021

Cited by 1 | Viewed by 1816

Abstract

A mixture of dodecanoic and hexanoic fatty acids was used to perform a simple and efficient microextraction method for industrial dyes such as methylene blue (MB), methyl violet (MV), and malachite green (MG) in aqueous solution. The fatty-acid microextractants were simply mixed and [...] Read more.

A mixture of dodecanoic and hexanoic fatty acids was used to perform a simple and efficient microextraction method for industrial dyes such as methylene blue (MB), methyl violet (MV), and malachite green (MG) in aqueous solution. The fatty-acid microextractants were simply mixed and heated until the mixture became homogeneous before adding it to the dye solutions. The fatty-acid solvent and its components were characterized with Fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (¹H NMR) measurements, while the dye concentrations were measured using UV-Vis spectroscopy. The performance of the extracting mixture was observed to vary across different dye contaminants, dosages of the extractant, concentrations of the dyes, and contact times. High extraction efficiencies of up to ~99% were obtained for MG as well as MV, and ~73% efficiency was achieved for MB. The study shows how a mixture of fatty acids can be used as a simple, efficient, green, and sustainable low-volume method for the removal of toxic industrial dyes in aqueous solutions. Full article

(This article belongs to the Special Issue Development and Application of Green or Sustainable Strategies in Analytical Chemistry)

► Show Figures

Graphical abstract

17 pages, 3218 KiB

Open AccessArticle

Optimum Parameters for Extracting Three Kinds of Carotenoids from Pepper Leaves by Response Surface Methodology

by Nenghui Li, Jing Li, Dongxia Ding, Jianming Xie, Jing Zhang, Wangxiong Li, Yufeng Ma, Feng Gao, Tianhang Niu, Cheng Wang and Emily Patience Bakpa

Separations 2021, 8(9), 134; https://doi.org/10.3390/separations8090134 - 26 Aug 2021

Cited by 5 | Viewed by 2156

Abstract

To determine the optimum parameters for extracting three carotenoids including zeaxanthin, lutein epoxide, and violaxanthin from pepper leaves by response surface methodology (RSM), a solvent of acetone and ethyl acetate (1:2) was used to extract carotenoids with four independent factors: ultrasound time (20–60 [...] Read more.

To determine the optimum parameters for extracting three carotenoids including zeaxanthin, lutein epoxide, and violaxanthin from pepper leaves by response surface methodology (RSM), a solvent of acetone and ethyl acetate (1:2) was used to extract carotenoids with four independent factors: ultrasound time (20–60 min); ratio of sample to solvent (1:12–1:4); saponification time (10–50 min); and concentration of saponification solution (KOH–methanol) (10–30%). A second-order polynomial model produced a satisfactory fitting of the experimental data with regard to zeaxanthin (R² = 75.95%, p < 0.0197), lutein epoxide (R² = 90.24%, p < 0.0001), and violaxanthin (R² = 73.84%, p < 0.0809) content. The optimum joint extraction conditions of zeaxanthin, lutein epoxide, and violaxanthin were 40 min, 1:8, 32 min, and 20%, respectively. The optimal predicted contents for zeaxanthin (0.823022 µg/g DW), lutein epoxide (4.03684 µg/g dry; DW—dry weight), and violaxanthin (16.1972 µg/g DW) in extraction had little difference with the actual experimental values obtained under the optimum extraction conditions for each response: zeaxanthin (0.8118 µg/g DW), lutein epoxide (3.9497 µg/g DW), and violaxanthin (16.1590 µg/g DW), which provides a theoretical basis and method for cultivating new varieties at low temperatures and weak light resistance. Full article

(This article belongs to the Collection Recent Trends in the Separation of Natural Products and Pharmaceuticals)

► Show Figures

Graphical abstract

8 pages, 1029 KiB

Open AccessFeature PaperArticle

Uncertainty of Size-Exclusion Chromatography Method in Quality Control of Bevacizumab Batches

by Alexis Oliva and Matías Llabrés

Separations 2021, 8(9), 133; https://doi.org/10.3390/separations8090133 - 25 Aug 2021

Cited by 2 | Viewed by 1899

Abstract

In addition to the analytical challenges related to the size and complexity of biopharmaceutical drugs, the inherent variability that arises due to their manufacturing process requires monitoring throughout the production process to ensure the safety and efficacy of the finished product. In this [...] Read more.

In addition to the analytical challenges related to the size and complexity of biopharmaceutical drugs, the inherent variability that arises due to their manufacturing process requires monitoring throughout the production process to ensure the safety and efficacy of the finished product. In this step, validation data should demonstrate that the process is controlled and reproducible, whereas the manufacturing process must ensure the quality and consistency of the product. For this, the manufacturer sets specification limits according with regulatory guidance. In such a situation, the comparison of different batches is required in order to describe and analyze the variability between them. However, it is unclear how great the variability of the analytical method would be or that in producing the batches. The estimation of the β-expectation tolerance intervals based on the variance components to account for both between-batch and within-batch variability was proposed as a specification limit to control the heterogeneity between batches at the time of manufacture and to verify whether batches meet specification limits. At this point, the variance components were computed by the maximum likelihood method using a linear random model. For this, the protein content, expressed as a percentage of the actual concentration relative to the claim value, and the dimer content (expressed as percentage) were used as critical quality attributes (CQAs) in the monitoring and control process. We used real data from six bevacizumab commercial batches. Full article

(This article belongs to the Special Issue Chromatographic and Electrophoretic Methods in Current Biomedical Analysis)

► Show Figures

Figure 1

13 pages, 3010 KiB

Open AccessArticle

Simultaneous Quantification of Diarylheptanoids and Phenolic Compounds in Juglans mandshurica Maxim. by UPLC–TQ-MS

by Hong Yang, Li-Bo Wang, Ya-Ping Guo, Ya-Li Wang, Xiao-Xiang Chen, Jian Huang, Lu Yang, Ke Zhang and Jin-Hui Wang

Separations 2021, 8(9), 132; https://doi.org/10.3390/separations8090132 - 25 Aug 2021

Cited by 1 | Viewed by 1598

Abstract

The immature epicarps of Juglans mandshurica and Juglans regia have been used as folk medicine for the treatment of cancer in China. Other parts of the J.mandshurica plant, including leaves, branches, barks, and stems, have reported antitumor activities. We previously found that [...] Read more.

The immature epicarps of Juglans mandshurica and Juglans regia have been used as folk medicine for the treatment of cancer in China. Other parts of the J.mandshurica plant, including leaves, branches, barks, and stems, have reported antitumor activities. We previously found that various diarylheptanoids and phenolic compounds isolated from J. mandshurica epicarps show significant antitumor activities. However, there are no reports of quantitative analysis of diarylheptanoids and phenolic compounds of J. mandshurica. In this study, a validated quantitative method, based on ultraperformance liquid chromatography coupled with triple-quadrupole tandem mass spectrometry, was employed to determine the contents of eight diarylheptanoids and seven phenolic compounds in the epicarps of J. mandshurica during different growth periods, in different parts of the plant, and in the epicarps of two Juglans species. The most successful J. mandshurica epicarp harvesting time fell between Day 12 and Day 27. The leaves of J. mandshurica showed potential for medical use as they had the highest content of the 15 compounds (3.399 ± 0.013 mg/g). We showed for the first time that the total content of diarylheptanoids in J. mandshurica is higher than that in J. regia, though, conversely, J. regia has higher contents of phenolic compounds. The method developed in this study is practical and simple and can be applied for quantitative analysis for evaluating the intrinsic quality of J. mandshurica. Full article

► Show Figures

Figure 1

Journal Menu

Journal Browser

Separations, Volume 8, Issue 9 (September 2021) – 33 articles

Further Information

Guidelines

MDPI Initiatives

Follow MDPI