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13 pages, 1399 KiB

Open AccessArticle

Application of Capillary and Free-Flow Zone Electrophoresis for Analysis and Purification of Antimicrobial β-Alanyl-Tyrosine from Hemolymph of Fleshfly Neobellieria bullata

by Veronika Šolínová, Petra Sázelová, Alice Mášová, Jiří Jiráček and Václav Kašička

Molecules 2021, 26(18), 5636; https://doi.org/10.3390/molecules26185636 - 16 Sep 2021

Cited by 6 | Viewed by 1841

Abstract

The problem of a growing resistance of bacteria and other microorganisms to conventional antibiotics gave rise to a search for new potent antimicrobial agents. Insect antimicrobial peptides (AMPs) seem to be promising novel potential anti-infective therapeutics. The dipeptide β-alanyl-tyrosine (β-Ala-Tyr) is one of [...] Read more.

The problem of a growing resistance of bacteria and other microorganisms to conventional antibiotics gave rise to a search for new potent antimicrobial agents. Insect antimicrobial peptides (AMPs) seem to be promising novel potential anti-infective therapeutics. The dipeptide β-alanyl-tyrosine (β-Ala-Tyr) is one of the endogenous insect toxins exhibiting antibacterial activity against both Gram-negative and Gram-positive bacteria. Prior to testing its other antimicrobial activities, it has to be prepared in a pure form. In this study, we have developed a capillary zone electrophoresis (CZE) method for analysis of β-Ala-Tyr isolated from the extract of the hemolymph of larvae of the fleshfly Neobellieria bullata by reversed-phase high-performance liquid chromatography (RP-HPLC). Based on our previously described correlation between CZE and free-flow zone electrophoresis (FFZE), analytical CZE separation of β-Ala-Tyr and its admixtures have been converted into preparative purification of β-Ala-Tyr by FFZE with preparative capacity of 45.5 mg per hour. The high purity degree of the β-Ala-Tyr obtained by FFZE fractionation was confirmed by its subsequent CZE analysis. Full article

(This article belongs to the Special Issue Theme Issue Honoring Professor Dr. Bogusław Buszewski on His 70th Birthday:"Separation Sciences & Related Techniques")

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23 pages, 5138 KiB

Open AccessArticle

Identification of Bacteria Associated with Post-Operative Wounds of Patients with the Use of Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry Approach

by Małgorzata Szultka-Młyńska, Daria Janiszewska, Paweł Pomastowski, Michał Złoch, Wojciech Kupczyk and Bogusław Buszewski

Molecules 2021, 26(16), 5007; https://doi.org/10.3390/molecules26165007 - 18 Aug 2021

Cited by 4 | Viewed by 2399

Abstract

The bacterial infection of post-operative wounds is a common health problem. Therefore, it is important to investigate fast and accurate methods of identifying bacteria in clinical samples. The aim of the study was to analyse the use of the MALDI-TOF MS technique to [...] Read more.

The bacterial infection of post-operative wounds is a common health problem. Therefore, it is important to investigate fast and accurate methods of identifying bacteria in clinical samples. The aim of the study was to analyse the use of the MALDI-TOF MS technique to identify microorganism wounds that are difficult to heal. The most common bacteria are Escherichia coli, Staphylococcus spp., and Enterococcus spp. We also demonstrate the effect of culture conditions, such as the used growth medium (solid: Brain Heart Infusion Agar, Mueller Hilton Agar, Glucose Bromocresol Purple Agar, and Vancomycin Resistance Enterococci Agar Base and liquid: Tryptic Soy Broth and BACTEC Lytic/10 Anaerobic/F), the incubation time (4, 6, and 24h), and the method of the preparation of bacterial protein extracts (the standard method based on the Bruker guideline, the Sepsityper method) to identify factors and the quality of the obtained mass spectra. By comparing the protein profiles of bacteria from patients not treated with antibiotics to those treated with antibiotics based on the presence/absence of specific signals and using the UniProt platform, it was possible to predict the probable mechanism of the action of the antibiotic used and the mechanism of drug resistance. Full article

(This article belongs to the Special Issue Theme Issue Honoring Professor Dr. Bogusław Buszewski on His 70th Birthday:"Separation Sciences & Related Techniques")

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18 pages, 2761 KiB

Open AccessArticle

Application of d-SPE before SPE and HPLC-FLD to Analyze Bisphenols in Human Breast Milk Samples

by Tomasz Tuzimski and Szymon Szubartowski

Molecules 2021, 26(16), 4930; https://doi.org/10.3390/molecules26164930 - 14 Aug 2021

Cited by 11 | Viewed by 2696

Abstract

In this study, we propose a simple, cost-effective, and sensitive high-performance liquid chromatography with fluorescence detection (HPLC-FLD) for the simultaneous determination of seven bisphenols (bisphenol F (BPF), bisphenol E (BPE), bisphenol B (BPB), BADGE (bisphenol A diglycidyl ether), BADGE∙2H₂O, BADGE∙H₂ [...] Read more.

In this study, we propose a simple, cost-effective, and sensitive high-performance liquid chromatography with fluorescence detection (HPLC-FLD) for the simultaneous determination of seven bisphenols (bisphenol F (BPF), bisphenol E (BPE), bisphenol B (BPB), BADGE (bisphenol A diglycidyl ether), BADGE∙2H₂O, BADGE∙H₂O, BADGE∙2HCl) in human breast milk samples. The dispersive solid phase extraction (d-SPE) coupled with solid phase extraction (SPE) procedure performed well for the majority of the analytes with recoveries in the range 57–88% and relative standard deviations (RSD%) of less than 9.4%. During the d-SPE stage, no significant matrix effect was observed thanks to the application of different pairs of salts such as zirconium-dioxide-based sorbents (Z-Sep or Z-Sep +) and primary secondary amine (PSA) or QuEChERS Enhanced Matrix Removal-Lipid (EMR-Lipid) and PSA. The method limits of quantification (mLOQs) for all investigated analytes were set at satisfactory low values in the range 171.89–235.11 ng mL⁻¹. Analyte concentrations were determined as the average value from human breast milk matrix samples. The results show that the d-SPE/SPE procedure, especially with the application of EMR-Lipid and PSA, could be used for further bisphenol analyses in human breast milk samples. Full article

(This article belongs to the Special Issue Theme Issue Honoring Professor Dr. Bogusław Buszewski on His 70th Birthday:"Separation Sciences & Related Techniques")

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12 pages, 1971 KiB

Open AccessArticle

A New Definition of the Stationary Phase Volume in Mixed-Mode Chromatographic Columns in Hydrophilic Liquid Chromatography

by Pavel Jandera and Tomáš Hájek

Molecules 2021, 26(16), 4819; https://doi.org/10.3390/molecules26164819 - 09 Aug 2021

Cited by 3 | Viewed by 1966

Abstract

Polar columns used in the HILIC (Hydrophilic Interaction Liquid Chromatography) systems take up water from the mixed aqueous–organic mobile phases in excess of the water concentration in the bulk mobile phase. The adsorbed water forms a diffuse layer, which becomes a part of [...] Read more.

Polar columns used in the HILIC (Hydrophilic Interaction Liquid Chromatography) systems take up water from the mixed aqueous–organic mobile phases in excess of the water concentration in the bulk mobile phase. The adsorbed water forms a diffuse layer, which becomes a part of the HILIC stationary phase and plays dominant role in the retention of polar compounds. It is difficult to fix the exact boundary between the diffuse stationary and the bulk mobile phase, hence determining the column hold-up volume is subject to errors. Adopting a convention that presumes that the volume of the adsorbed water can be understood as the column stationary phase volume enables unambiguous determination of the volumes of the stationary and of the mobile phases in the column, which is necessary for obtaining thermodynamically correct chromatographic data in HILIC systems. The volume of the aqueous stationary phase, Vex, can be determined experimentally by frontal analysis combined with Karl Fischer titration method, yielding isotherms of water adsorbed on polar columns, which allow direct prediction of the effects of the composition of aqueous–organic mobile phase on the retention in HILIC systems, and more accurate determination of phase volumes in columns and consistent retention data for any mobile phase composition. The n phase volume ratios of 18 columns calculated according to the new phase convention strongly depend on the type of the polar column. Zwitterionic and TSK gel amide and amine columns show especially strong water adsorption. Full article

(This article belongs to the Special Issue Theme Issue Honoring Professor Dr. Bogusław Buszewski on His 70th Birthday:"Separation Sciences & Related Techniques")

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13 pages, 2357 KiB

Open AccessArticle

Studies on the Processes of Electron Capture and Clustering of Benzyl Chloride by Ion Mobility Spectrometry

by Izabela Wolańska, Edyta Budzyńska and Jarosław Puton

Molecules 2021, 26(15), 4562; https://doi.org/10.3390/molecules26154562 - 28 Jul 2021

Cited by 2 | Viewed by 1920

Abstract

This paper presents the results of the study on the course of the benzyl chloride (BzCl) ionization process in a drift tube ion mobility spectrometer (DT IMS) in which nitrogen was used as the carrier gas. BzCl ionization follows the dissociative electron capture [...] Read more.

This paper presents the results of the study on the course of the benzyl chloride (BzCl) ionization process in a drift tube ion mobility spectrometer (DT IMS) in which nitrogen was used as the carrier gas. BzCl ionization follows the dissociative electron capture mechanism. The chloride ions produced in this process take part in the formation of cluster ions. Using DT IMS allows for estimation of the value of the electron attachment rate for BzCl and the equilibrium constant for the cluster ion formation. The basic experimental method used in this work was to analyze drift time spectra obtained for the introduction of the sample to the spectrometer with the drift gas. The theoretical interpretation of the results is based on the mathematical description of the ion transport. This description takes into account the phenomenon of diffusion, as well as the processes of formation and dissociation of ionic clusters occurring during the movement of ions in the drift section. Full article

(This article belongs to the Special Issue Theme Issue Honoring Professor Dr. Bogusław Buszewski on His 70th Birthday:"Separation Sciences & Related Techniques")

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14 pages, 4637 KiB

Open AccessFeature PaperArticle

Electroreduction of Bi(III) Ions at a Cyclically Renewable Liquid Silver Amalgam Film Electrode in the Presence of Methionine

by Agnieszka Nosal-Wiercińska, Marlena Martyna, Valentin Mirčeski and Sławomira Skrzypek

Molecules 2021, 26(13), 3972; https://doi.org/10.3390/molecules26133972 - 29 Jun 2021

Cited by 2 | Viewed by 1538

Abstract

The catalytic influence of methionine (Mt) on the electroreduction of Bi(III) ions on the novel, cyclically renewable liquid silver amalgam film electrode (R–AgLAFE) in a non-complexing electrolyte solution was examined. The presence of methionine leads to a multistep reaction mechanism, where the transfer [...] Read more.

The catalytic influence of methionine (Mt) on the electroreduction of Bi(III) ions on the novel, cyclically renewable liquid silver amalgam film electrode (R–AgLAFE) in a non-complexing electrolyte solution was examined. The presence of methionine leads to a multistep reaction mechanism, where the transfer of the first electron is the rate limiting step, which is the subject of catalytic augmentation. The catalytic activity of methionine is a consequence of its ability to remove water molecules from the bismuth ion coordination sphere, as well as to form active complexes on the electrode surface, facilitating the electron transfer process. Full article

(This article belongs to the Special Issue Theme Issue Honoring Professor Dr. Bogusław Buszewski on His 70th Birthday:"Separation Sciences & Related Techniques")

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13 pages, 430 KiB

Open AccessArticle

Phytochemical Fingerprinting and In Vitro Antimicrobial and Antioxidant Activity of the Aerial Parts of Thymus marschallianus Willd. and Thymus seravschanicus Klokov Growing Widely in Southern Kazakhstan

by Bagda Sagynaikyzy Zhumakanova, Izabela Korona-Głowniak, Krystyna Skalicka-Woźniak, Agnieszka Ludwiczuk, Tomasz Baj, Krzysztof Kamil Wojtanowski, Aleksandra Józefczyk, Karlygash Altynbekovna Zhaparkulova, Zuriyadda Bektemirova Sakipova and Anna Malm

Molecules 2021, 26(11), 3193; https://doi.org/10.3390/molecules26113193 - 26 May 2021

Cited by 17 | Viewed by 3670

Abstract

The chemical composition of the hydroethanolic extracts (60% v/v) from the aerial parts of Thymus marschallianus Willd (TM) and Thymus seravschanicus Klokov (TS) from Southern Kazakhstan flora was analyzed together with their hexane fractions. Determination of antibacterial, antifungal and antioxidant activities of [...] Read more.

The chemical composition of the hydroethanolic extracts (60% v/v) from the aerial parts of Thymus marschallianus Willd (TM) and Thymus seravschanicus Klokov (TS) from Southern Kazakhstan flora was analyzed together with their hexane fractions. Determination of antibacterial, antifungal and antioxidant activities of both extracts was also performed. RP-HPLC/PDA and HPLC/ESI-QTOF-MS showed that there were some differences between the composition of both extracts. The most characteristic components of TM were rosmarinic acid, protocatechuic acid, luteolin 7-O-glucoside, and apigenin 7-O-glucuronide, while protocatechuic acid, luteolin 7-O-glucoside, luteolin 7-O-glucuronide, and eriodictyol predominated in TS. The content of polyplenols was higher in TS than in TM. The GC-MS analysis of the volatile fraction of both examined extracts revealed the presence of thymol and carvacrol. Additionally, sesquiterpenoids, fatty acids, and their ethyl esters were found in TM, and fatty acid methyl esters in TS. The antioxidant activity of both extracts was similar. The antibacterial activity of TS extract was somewhat higher than TM, while antifungal activity was the same. TS extract was the most active against Helicobacter pylori ATCC 43504 with MIC (minimal inhibitory concentration) = 0.625 mg/mL, exerting a bactericidal effect. The obtained data provide novel information about the phytochemistry of both thyme species and suggest new potential application of TS as a source of bioactive compounds, especially with anti-H. pylori activity. Full article

(This article belongs to the Special Issue Theme Issue Honoring Professor Dr. Bogusław Buszewski on His 70th Birthday:"Separation Sciences & Related Techniques")

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17 pages, 1516 KiB

Open AccessArticle

Evaluation of Analytes Characterized with Potential Protective Action after Rat Exposure to Lead

by Ivan Liakh, Darya Harshkova, Anastasiya Pauliukavets, Vladimir Sheibak, Tomasz Bączek and Natalia Miękus

Molecules 2021, 26(8), 2163; https://doi.org/10.3390/molecules26082163 - 09 Apr 2021

Viewed by 1903

Abstract

Lead (Pb) was revealed for its role as a neurodevelopmental toxin. The determination of neurotransmitters (NTs) in particular brain regions could ameliorate the precise description and optimization of therapeutic protocols able to restore the harmony of signaling pathways in nervous and immune systems. [...] Read more.

Lead (Pb) was revealed for its role as a neurodevelopmental toxin. The determination of neurotransmitters (NTs) in particular brain regions could ameliorate the precise description and optimization of therapeutic protocols able to restore the harmony of signaling pathways in nervous and immune systems. The determination of selected analytes from the group of NTs based on the liquid chromatography (LC)-based method was carried out to illustrate the changes of amino acid (AA) and biogenic amine (BA) profiles observed in chosen immune and nervous systems rat tissues after Pb intoxication. Also, a protective combination of AA was proposed to correct the changes caused by Pb intoxication. After the administration of Pb, changes were observed in all organs studied and were characterized by a fluctuation of NT concentrations in immune and nervous systems (hypothalamus samples). Using a protective mixture of bioactive compounds prevented numerous changes in the balance of NT. The combined analysis of the immune and nervous system while the normalizing effect of curative agents on the level of differentially secreted NTs and AA is studied could present a new approach to the harmonization of those two essential systems after Pb intoxication. Full article

(This article belongs to the Special Issue Theme Issue Honoring Professor Dr. Bogusław Buszewski on His 70th Birthday:"Separation Sciences & Related Techniques")

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14 pages, 1917 KiB

Open AccessArticle

Determination of Cytotoxic Activity of Sanguinaria canadensis Extracts against Human Melanoma Cells and Comparison of Their Cytotoxicity with Cytotoxicity of Some Anticancer Drugs

by Tomasz Tuzimski, Anna Petruczynik, Tomasz Plech, Barbara Kaproń, Anna Makuch-Kocka, Małgorzata Szultka-Młyńska, Justyna Misiurek and Bogusław Buszewski

Molecules 2021, 26(6), 1738; https://doi.org/10.3390/molecules26061738 - 20 Mar 2021

Cited by 10 | Viewed by 2179

Abstract

Melanoma is an enormous global health burden, and should be effectively addressed with better therapeutic strategies. Therefore, new therapeutic agents are needed for the management of this disease. The aim of this study was the investigation of cytotoxic activity of some isoquinoline alkaloid [...] Read more.

Melanoma is an enormous global health burden, and should be effectively addressed with better therapeutic strategies. Therefore, new therapeutic agents are needed for the management of this disease. The aim of this study was the investigation of cytotoxic activity of some isoquinoline alkaloid standards and extracts obtained from Sanguinaria canadensis—collected before, during, and after flowering—against three different human melanoma cells (A375, G361, SK-MEL-3). The cytotoxicity of these extracts was not previously tested on these melanoma cell lines. Determination of alkaloid contents was performed by HPLC-DAD using Polar RP column and mobile phase containing acetonitrile, water, and 1-butyl-3-methylimidazolium tetrafluoroborate. The cytotoxicity of alkaloid standards was investigated by determination of cell viability and calculation of IC₅₀ values. Significant differences were observed in the alkaloids content and cytotoxic activity of the extracts, depending on the season of collection of the plant material. In the Sanguinaria canadensis extracts high contents of sanguinarine (from 4.8543 to 9.5899 mg/g of dry plant material) and chelerythrine (from 42.7224 to 6.8722 mg/g of dry plant material) were found. For both of these alkaloids, very high cytotoxic activity against the tested cell lines were observed. The IC₅₀ values were in the range of 0.11–0.54 µg/mL for sanguinarine and 0.14 to 0.46 µg/mL for chelerythrine. IC₅₀ values obtained for Sanguinaria canadensis extracts against all tested cell lines were also very low (from 0.88 to 10.96 µg/mL). Cytotoxic activity of alkaloid standards and Sanguinaria canadensis extracts were compared with the cytotoxicity of anticancer drugs—etoposide, cisplatin, and hydroxyurea. In all cases except the one obtained for cisplatin against A375, which was similar to that obtained for Sanguinaria canadensis after flowering against the same cell line, IC₅₀ values obtained for anticancer drugs were higher than the IC₅₀ values obtained for sanguinarine, chelerythrine, and Sanguinaria canadensis extracts. Our results showed that Sanguinaria canadensis extracts and isoquinoline alkaloids, especially sanguinarine and chelerythrine, could be recommended for further in vivo experiments in order to confirm the possibility of their application in the treatment of human melanomas. Full article

(This article belongs to the Special Issue Theme Issue Honoring Professor Dr. Bogusław Buszewski on His 70th Birthday:"Separation Sciences & Related Techniques")

17 pages, 5975 KiB

Open AccessArticle

Determination of Cytotoxic Activity of Selected Isoquinoline Alkaloids and Plant Extracts Obtained from Various Parts of Mahonia aquifolium Collected in Various Vegetation Seasons

by Tomasz Tuzimski, Anna Petruczynik, Barbara Kaproń, Anna Makuch-Kocka, Małgorzata Szultka-Młyńska, Justyna Misiurek, Grażyna Szymczak and Bogusław Buszewski

Molecules 2021, 26(4), 816; https://doi.org/10.3390/molecules26040816 - 04 Feb 2021

Cited by 6 | Viewed by 2690

Abstract

Melanoma is a serious form of skin cancer that begins in cells known as melanocytes. While it is less common than the other forms of skin cancer, melanoma is more dangerous because of its ability to spread to other organs more rapidly if [...] Read more.

Melanoma is a serious form of skin cancer that begins in cells known as melanocytes. While it is less common than the other forms of skin cancer, melanoma is more dangerous because of its ability to spread to other organs more rapidly if it is not treated at an early stage. The number of people diagnosed with melanoma has increased over the last few decades. The most widely used treatments include surgery, chemotherapy, and radiation therapy. The search for new drugs to treat various cancers is one of the most important challenges of modern scientific research. Some isoquinoline alkaloids found in different plant species have strong cytotoxic effects on various cancer cells. We tested the effect of isoquinoline alkaloids and extracts obtained from various parts of Mahonia aquifolium collected in various vegetation seasons on human melanoma cancer cells and our data indicated that investigated extract induced significant reduction in cell viability of Human malignant melanoma cells (A375), human Caucasian malignant melanoma cell line (G361), and human malignant melanoma cell line (SKMEL3 cancer cell lines in a dose- and time-dependent manner. Differences in cytotoxic activity were observed for extracts obtained from various parts of Mahonia aquifolium. Significant differences were also obtained in the alkaloids content and cytotoxic activity of the extracts depending on the season of collection of plant material. Our investigations exhibit that these plant extracts can be recommended for further in vivo experiments in order to confirm the possibility of their use in the treatment of human melanomas. Full article

(This article belongs to the Special Issue Theme Issue Honoring Professor Dr. Bogusław Buszewski on His 70th Birthday:"Separation Sciences & Related Techniques")

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13 pages, 1316 KiB

Open AccessArticle

Application of HPLC-DAD for In Vitro Investigation of Acetylcholinesterase Inhibition Activity of Selected Isoquinoline Alkaloids from Sanguinaria canadensis Extracts

by Tomasz Tuzimski and Anna Petruczynik

Molecules 2021, 26(1), 230; https://doi.org/10.3390/molecules26010230 - 05 Jan 2021

Cited by 8 | Viewed by 3019

Abstract

Isoquinoline alkaloids may have a wide range of pharmacological activities. Some of them have acetylcholinesterase activity inhibition. Nowadays, neurodegenerative disorders such as Alzheimer’s disease have become a serious public health problem. Searching for new effective compounds with inhibited acetylcholinesterase activity is one of [...] Read more.

Isoquinoline alkaloids may have a wide range of pharmacological activities. Some of them have acetylcholinesterase activity inhibition. Nowadays, neurodegenerative disorders such as Alzheimer’s disease have become a serious public health problem. Searching for new effective compounds with inhibited acetylcholinesterase activity is one of the most significant challenges of modern scientific research. The aim of this study was the in vitro investigation of acetylcholinesterase activity inhibition of extracts obtained from Sanguinaria canadensis collected before, during and after flowering. The acetylcholinesterase activity inhibition of these extracts has not been previously tested. The aim was also to quantify selected alkaloids in the investigated extracts by high performance liquid chromatography (HPLC). The analyses of alkaloid content were performed using HPLC in reversed phase (RP) mode using Polar RP column and mobile phase containing acetonitrile, water and ionic liquid (IL). The acetylcholinesterase activity inhibition of the tested plant extracts and respective alkaloid standards were examined using high performance liquid chromatography with diode-array detector (HPLC-DAD) for the quantification of 5-thio-2-nitro-benzoic acid, which is the product of the reaction between the thiocholine (product of the hydrolysis of acetylthiocholine reaction) with Ellman reagent. The application of the HPLC method allowed for elimination of absorption of interfering components, for example, alkaloids such as sanguinarine and berberine. It is revealed that the HPLC method can be successfully used for the evaluation of the acetylcholinesterase inhibitory activity in samples such as plant extracts, especially those containing colored components adsorbing at wavelength in the range 405–412 nm. The acetylcholinesterase inhibition activity synergy of pairs of alkaloid standards and mixture of all investigated alkaloids was also determined. Most investigated alkaloids and all Sanguinaria canadensis extracts exhibited very high acetylcholinesterase activity inhibition. IC₅₀ values obtained for alkaloid standards were from 0.36 for berberine to 23.13 µg/mL for protopine and from 61.24 to 89.14 µg/mL for Sanguinaria canadensis extracts. Our investigations demonstrated that these plant extracts can be recommended for further in vivo experiments to confirm their acetylcholinesterase activity inhibition. Full article

(This article belongs to the Special Issue Theme Issue Honoring Professor Dr. Bogusław Buszewski on His 70th Birthday:"Separation Sciences & Related Techniques")

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13 pages, 1887 KiB

Open AccessArticle

Development of an Atmospheric Pressure Chemical Ionization Interface for GC-MS

by Christian Lipok, Florian Uteschil and Oliver J. Schmitz

Molecules 2020, 25(14), 3253; https://doi.org/10.3390/molecules25143253 - 16 Jul 2020

Cited by 7 | Viewed by 4369

Abstract

A closed atmospheric pressure chemical ionization (APCI) ion source as interface between a gas chromatograph (GC) and a triple quadrupole mass spectrometer (QqQ-MS) was developed. The influence of different ion source conditions, such as humidity, make-up gas flow, and the position of the [...] Read more.

A closed atmospheric pressure chemical ionization (APCI) ion source as interface between a gas chromatograph (GC) and a triple quadrupole mass spectrometer (QqQ-MS) was developed. The influence of different ion source conditions, such as humidity, make-up gas flow, and the position of the GC column, were investigated and determined as main factors to increase sensitivity and repeatability of the system. For a performance test under real conditions, the new APCI ion source was used for the determination of plant protection products in commercially available coffee beans from Vietnam. The ionization behavior was investigated and the majority of the analytes were detected as [MH]⁺, [M]^+∙, or as characteristic fragment ions, which have been assigned to ion source fragmentation. The developed GC-MS methods are based on tandem MS (MS/MS) and revealed for the plant protection products limits of detection (LOD) between 1 and 250 pg on column and relative standard derivations for all compounds < 16%. The used ultrasonic solid–liquid extraction yielded recovery rates of approximately 60 to 100%. Residues of herbicide methyl esters, organophosphorus compounds, and organonitrogen compounds have been detected in the analyzed coffee beans. Full article

(This article belongs to the Special Issue Theme Issue Honoring Professor Dr. Bogusław Buszewski on His 70th Birthday:"Separation Sciences & Related Techniques")

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14 pages, 1756 KiB

Open AccessArticle

Prediction of Chromatographic Elution Order of Analytical Mixtures Based on Quantitative Structure-Retention Relationships and Multi-Objective Optimization

by Petar Žuvela, J. Jay Liu, Ming Wah Wong and Tomasz Bączek

Molecules 2020, 25(13), 3085; https://doi.org/10.3390/molecules25133085 - 06 Jul 2020

Cited by 7 | Viewed by 2933

Abstract

Prediction of the retention time from the molecular structure using quantitative structure-retention relationships is a powerful tool for the development of methods in reversed-phase HPLC. However, its fundamental limitation lies in the fact that low error in the prediction of the retention time [...] Read more.

Prediction of the retention time from the molecular structure using quantitative structure-retention relationships is a powerful tool for the development of methods in reversed-phase HPLC. However, its fundamental limitation lies in the fact that low error in the prediction of the retention time does not necessarily guarantee a prediction of the elution order. Here, we propose a new method for the prediction of the elution order from quantitative structure-retention relationships using multi-objective optimization. Two case studies were evaluated: (i) separation of organic molecules in a Supelcosil LC-18 column, and (ii) separation of peptides in seven columns under varying conditions. Results have shown that, when compared to predictions based on the conventional model, the relative root mean square error of the elution order decreases by 48.84%, while the relative root mean square error of the retention time increases by 4.22% on average across both case studies. The predictive ability in terms of both retention time and elution order and the corresponding applicability domains were defined. The models were deemed stable and robust with few to no structural outliers. Full article

(This article belongs to the Special Issue Theme Issue Honoring Professor Dr. Bogusław Buszewski on His 70th Birthday:"Separation Sciences & Related Techniques")

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12 pages, 2709 KiB

Open AccessArticle

Rutamarin: Efficient Liquid–Liquid Chromatographic Isolation from Ruta graveolens L. and Evaluation of Its In Vitro and In Silico MAO-B Inhibitory Activity

by Ewelina Kozioł, Simon Vlad Luca, Hale Gamze Ağalar, Begüm Nurpelin Sağlık, Fatih Demirci, Laurence Marcourt, Jean-Luc Wolfender, Krzysztof Jóźwiak and Krystyna Skalicka-Woźniak

Molecules 2020, 25(11), 2678; https://doi.org/10.3390/molecules25112678 - 09 Jun 2020

Cited by 12 | Viewed by 2930

Abstract

Naturally occurring coumarins are a group of compounds with many documented central nervous system (CNS) activities. However, dihydrofuranocoumarins have been infrequently investigated for their bioactivities at CNS level. Within the frame of this study, an efficient liquid–liquid chromatography method was developed to rapidly [...] Read more.

Naturally occurring coumarins are a group of compounds with many documented central nervous system (CNS) activities. However, dihydrofuranocoumarins have been infrequently investigated for their bioactivities at CNS level. Within the frame of this study, an efficient liquid–liquid chromatography method was developed to rapidly isolate rutamarin from Ruta graveolens L. (Rutaceae) dichloromethane extract (DCM). The crude DCM (9.78 mg/mL) and rutamarin (6.17 M) were found to be effective inhibitors of human monoamine oxidase B (hMAO-B) with inhibition percentages of 89.98% and 95.26%, respectively. The inhibitory activity against human monoamine oxidase A (hMAO-A) for the DCM extract was almost the same (88.22%). However, for rutamarin, it significantly dropped to 25.15%. To examine the molecular interaction of rutamarin with hMAO- B, an in silico evaluation was implemented. A docking study was performed for the two enantiomers (R)-rutamarin and (S)-rutamarin. The (S)-rutamarin was found to bind stronger to the hMAO-B binging cavity. Full article

(This article belongs to the Special Issue Theme Issue Honoring Professor Dr. Bogusław Buszewski on His 70th Birthday:"Separation Sciences & Related Techniques")

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Review

Jump to: Research

32 pages, 3221 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Breath Biomarkers in Diagnostic Applications

by Y Lan Pham and Jonathan Beauchamp

Molecules 2021, 26(18), 5514; https://doi.org/10.3390/molecules26185514 - 11 Sep 2021

Cited by 24 | Viewed by 7203

Abstract

The detection of chemical compounds in exhaled human breath presents an opportunity to determine physiological state, diagnose disease or assess environmental exposure. Recent advancements in metabolomics research have led to improved capabilities to explore human metabolic profiles in breath. Despite some notable challenges [...] Read more.

The detection of chemical compounds in exhaled human breath presents an opportunity to determine physiological state, diagnose disease or assess environmental exposure. Recent advancements in metabolomics research have led to improved capabilities to explore human metabolic profiles in breath. Despite some notable challenges in sampling and analysis, exhaled breath represents a desirable medium for metabolomics applications, foremost due to its non-invasive, convenient and practically limitless availability. Several breath-based tests that target either endogenous or exogenous gas-phase compounds are currently established and are in practical and/or clinical use. This review outlines the concept of breath analysis in the context of these unique tests and their applications. The respective breath biomarkers targeted in each test are discussed in relation to their physiological production in the human body and the development and implementation of the associated tests. The paper concludes with a brief insight into prospective tests and an outlook of the future direction of breath research. Full article

(This article belongs to the Special Issue Theme Issue Honoring Professor Dr. Bogusław Buszewski on His 70th Birthday:"Separation Sciences & Related Techniques")

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69 pages, 6280 KiB

Open AccessReview

Review of Chromatographic Methods Coupled with Modern Detection Techniques Applied in the Therapeutic Drugs Monitoring (TDM)

by Tomasz Tuzimski and Anna Petruczynik

Molecules 2020, 25(17), 4026; https://doi.org/10.3390/molecules25174026 - 03 Sep 2020

Cited by 62 | Viewed by 8769

Abstract

Therapeutic drug monitoring (TDM) is a tool used to integrate pharmacokinetic and pharmacodynamics knowledge to optimize and personalize various drug therapies. The optimization of drug dosing may improve treatment outcomes, reduce toxicity, and reduce the risk of developing drug resistance. To adequately implement [...] Read more.

Therapeutic drug monitoring (TDM) is a tool used to integrate pharmacokinetic and pharmacodynamics knowledge to optimize and personalize various drug therapies. The optimization of drug dosing may improve treatment outcomes, reduce toxicity, and reduce the risk of developing drug resistance. To adequately implement TDM, accurate and precise analytical procedures are required. In clinical practice, blood is the most commonly used matrix for TDM; however, less invasive samples, such as dried blood spots or non-invasive saliva samples, are increasingly being used. The choice of sample preparation method, type of column packing, mobile phase composition, and detection method is important to ensure accurate drug measurement and to avoid interference from matrix effects and drug metabolites. Most of the reported procedures used liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) techniques due to its high selectivity and sensitivity. High-performance chromatography with ultraviolet detection (HPLC-UV) methods are also used when a simpler and more cost-effective methodology is desired for clinical monitoring. The application of high-performance chromatography with fluorescence detection (HPLC-FLD) with and without derivatization processes and high-performance chromatography with electrochemical detection (HPLC-ED) techniques for the analysis of various drugs in biological samples for TDM have been described less often. Before chromatographic analysis, samples were pretreated by various procedures—most often by protein precipitation, liquid–liquid extraction, and solid-phase extraction, rarely by microextraction by packed sorbent, dispersive liquid–liquid microextraction. The aim of this article is to review the recent literature (2010–2020) regarding the use of liquid chromatography with various detection techniques for TDM. Full article

(This article belongs to the Special Issue Theme Issue Honoring Professor Dr. Bogusław Buszewski on His 70th Birthday:"Separation Sciences & Related Techniques")

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