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Aslani S, Armstrong DW. High Information Spectroscopic Detection Techniques for Gas Chromatography. J Chromatogr A 2022; 1676:463255. [DOI: 10.1016/j.chroma.2022.463255] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 06/10/2022] [Accepted: 06/14/2022] [Indexed: 01/14/2023]
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2
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Physiological and Qualitative Response of Cucurbita pepo L. to Salicylic Acid under Controlled Water Stress Conditions. HORTICULTURAE 2022. [DOI: 10.3390/horticulturae8010079] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Limited water stress is one of the most important environmental stresses that affect the growth, quantity and quality of agronomic crops. This study was undertaken to investigate the effect of foliar applied salicylic acid (SA) on physiological responses, antioxidant enzymes and qualitative traits of Cucurbita pepo L. Plants exposed to water-stressed conditions in two years of field studies. Irrigation regimes at three soil matric potential levels (−0.3, −1.2 and −1.8 MPa) and SA at four levels (0.0, 0.5, 1.0 and 1.5 mg/L) were considered as main plot and sub-plots, respectively. The soil matric potential values (MPa) was measured just before irrigation. Results showed that under water stressed conditions alone, the amounts of malondialdehyde (MDA), hydrogen peroxide (H2O2) and ion leakage were higher compared with control treatment. However, spraying of SA under both water stress and non-stress conditions reduced the values of the above parameters. Water stress increased CAT, APX and GR enzymes activity. However foliar application of SA led to the decrease of CAT, APX and GR under all soil matric potential levels. The amount of carbohydrates and fatty acids increased with the intensity of water stress and SA modulated this response. By increasing SA concentration both in optimum and stress conditions, saturated fatty acids content decreased. According to our data, the SA application is an effective approach to improve pumpkin growth under water stress conditions.
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Hosbas Coskun S, Wise SA, Kuszak AJ. The Importance of Reference Materials and Method Validation for Advancing Research on the Health Effects of Dietary Supplements and Other Natural Products. Front Nutr 2021; 8:786261. [PMID: 34970578 PMCID: PMC8713974 DOI: 10.3389/fnut.2021.786261] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 11/17/2021] [Indexed: 01/21/2023] Open
Abstract
Insufficient assessment of the identity and chemical composition of complex natural products, including botanicals, herbal remedies, and dietary supplements, hinders reproducible research and limits understanding mechanism(s) of action and health outcomes, which in turn impede improvements in clinical practice and advances in public health. This review describes available analytical resources and good methodological practices that support natural product characterization and strengthen the knowledge gained for designing and interpreting safety and efficacy investigations. The practice of validating analytical methods demonstrates that measurements of constituents of interest are reproducible and appropriate for the sample (e.g., plant material, phytochemical extract, and biological specimen). In particular, the utilization of matrix-based reference materials enables researchers to assess the accuracy, precision, and sensitivity of analytical measurements of natural product constituents, including dietary ingredients and their metabolites. Select case studies are presented where the careful application of these resources and practices has enhanced experimental rigor and benefited research on dietary supplement health effects.
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Affiliation(s)
| | | | - Adam J. Kuszak
- Office of Dietary Supplements, National Institutes of Health, Bethesda, MD, United States
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5
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Zhao X, Zhang S, Huang Q, Peng C, Feng Y, Xing J. Regulation of hydrogen bond acidity and its effect on separation performances. J Chromatogr A 2021; 1657:462556. [PMID: 34601256 DOI: 10.1016/j.chroma.2021.462556] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 09/09/2021] [Accepted: 09/09/2021] [Indexed: 11/18/2022]
Abstract
Ionic liquid bonded polysiloxanes (PILs) are a class of polysiloxanes whose side chains contain ionic liquid (IL) moieties. They not only inherit the character of "dual nature" from ILs but also inherit the excellent film-forming ability and thermal stability from polysiloxanes. In this paper, the solvation parameter model is introduced to investigate the interaction characteristics of PILs. The experimental results show that the b values of PILs occur in a wider range than those previously reported for the stationary phases. The hydrogen bond acidity can be effectively adjusted by varying the ionic liquid content or substituents. Hindering the formation of the hydrogen-bonded networks and increasing the exposed hydrogens may be intrinsic to the strong hydrogen bond acidity of PILs. Subsequently, the separation performances of these PIL stationary phases were demonstrated by separating various mixed samples of aromatic isomers, dichloroanilines, substituted alkanes, alcohols, esters, etc. The results show that the PILs with strong hydrogen bond acidity have excellent selectivity performances for aromatic position isomers, alcohols, and substituted alkanes. This study is significant for understanding the hydrogen bond acidity and broadening the range of hydrogen bond acidity of ionic liquid stationary phases.
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Affiliation(s)
- Xiaojie Zhao
- Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, Hubei 430072, China; School of Environmental Engineering and Chemistry, Luoyang Institute of Science and Technology, Luoyang 471023, China
| | - Shaowen Zhang
- School of Environmental Engineering and Chemistry, Luoyang Institute of Science and Technology, Luoyang 471023, China
| | - Qing Huang
- Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, Hubei 430072, China
| | - Chuanyun Peng
- School of Environmental Engineering and Chemistry, Luoyang Institute of Science and Technology, Luoyang 471023, China
| | - Yong Feng
- School of Environmental Engineering and Chemistry, Luoyang Institute of Science and Technology, Luoyang 471023, China
| | - Jun Xing
- Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, Hubei 430072, China.
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6
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Pauls RE, Pease B. Separation of Fatty Acid Dimethyl Esters on an Ionic Liquid Gas Chromatographic Column. J Chromatogr Sci 2021; 59:205-211. [PMID: 33275654 DOI: 10.1093/chromsci/bmaa097] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 08/06/2020] [Accepted: 10/26/2020] [Indexed: 11/14/2022]
Abstract
An ionic liquid (IL) 111 column was compared with other commonly employed stationary phases including polydimethyl siloxane and polyethylene glycol for the separation of fatty acid monomethyl and dimethyl esters. The fatty acid esters employed in this study were derived from metathesis reactions of vegetable oils both with and without olefins. The IL 111 column demonstrated enhanced performance compared with conventional columns for the separation of these esters. These advantages included significantly enhanced retention of dimethyl esters relative to monomethyl esters, excellent cis/trans isomer separation and the ability to analyze higher carbon number dimethyl esters. As a result, these columns are highly suited for the analysis of mixtures of mono- and dimethyl fatty acid esters found in lipid metathesis reaction products or to determine monofunctional impurities in samples of commercial dimethyl esters.
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Affiliation(s)
- R E Pauls
- R. E. Pauls Consulting, 724 West Bauer Road, Naperville, IL 60563, USA
| | - B Pease
- Elevance Renewable Sciences, 2501 Davey Road, Woodridge, IL 60517, USA
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Liu XM, Zhang Y, Zhou Y, Li GH, Zeng BQ, Zhang JW, Feng XS. Progress in Pretreatment and Analysis of Fatty Acids in Foods: An Update since 2012. SEPARATION & PURIFICATION REVIEWS 2021. [DOI: 10.1080/15422119.2019.1673776] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Xiao-Min Liu
- School of Pharmacy, China Medical University, Shenyang, China
| | - Yuan Zhang
- Department of Pharmacy, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yu Zhou
- Department of Pharmacy, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Guo-Hui Li
- Department of Pharmacy, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Ben-Qing Zeng
- Department of Pharmacy, The First People’s Hospital of Longquanyi District, Chengdu, China
| | - Jian-Wei Zhang
- Department of Abdominal Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xue-Song Feng
- School of Pharmacy, China Medical University, Shenyang, China
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8
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A critical comparison of vacuum UV (VUV) spectrometer and electron ionization single quadrupole mass spectrometer detectors for the analysis of alkylbenzenes in gasoline by gas chromatography: Experimental and statistical aspects. Talanta 2021; 225:122081. [PMID: 33592794 DOI: 10.1016/j.talanta.2021.122081] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 12/17/2020] [Accepted: 12/31/2020] [Indexed: 11/24/2022]
Abstract
Recent advances in benchtop vacuum ultraviolet (VUV) spectrometers have yielded effective universal detectors for gas chromatography (GC). The ability of these detectors to acquire absorbance spectra from 125 nm to 430 nm poses an alternative to the gold standard of mass spectrometry (MS) as a sensitive and selective GC detector. The applications of GC/VUV extend into many areas. Featured here is the potential application of GC/VUV to the analysis of ignitable liquids, which may be found on debris from suspected arson fires. A particular compound class of interest is the alkylbenzenes, as they are a significant component in fuels such as gasoline, petroleum distillates, and aromatic solvents such as degreasers and cleaning solvents. To measure the sensitivity, selectivity and specificity of GC-VUV and GC-MS for alkylbenzenes we employed both library search methods and chemometric analysis using discriminant analysis. The GC-VUV detector was found to have superior specificity to the GC-MS detector in full scan mode. The GC-VUV detector was able to identify all alkylbenzenes correctly, including the correct identification of all structural isomers. LODs for both GC-VUV and GC-MS were found to be picograms on column.
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9
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Cruse CA, Goodpaster JV. Thermal and spectroscopic analysis of nitrated compounds and their break-down products using gas chromatography/vacuum UV spectroscopy (GC/VUV). Anal Chim Acta 2021; 1143:117-123. [PMID: 33384109 DOI: 10.1016/j.aca.2020.11.041] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 10/22/2020] [Accepted: 11/28/2020] [Indexed: 11/29/2022]
Abstract
Gas chromatography/vacuum UV spectroscopy (GC/VUV) was utilized to study various explosives and pharmaceuticals in the nitrate ester and nitramine structural classes. In addition to generating specific VUV spectra for each compound, VUV was used to indicate the onset of thermal decomposition based upon the appearance of break-down products such as nitric oxide, carbon monoxide, formaldehyde, water, and molecular oxygen. The effect of temperature on decomposition could be fit to a logistical function where the fraction of intact compound remaining decreased as the transfer line/flow cell temperature was increased from 200 °C to 300 °C. Utilizing this relationship, the decomposition temperatures for the nitrate ester and nitramine compounds were determined to range between 244 °C and 277 °C. It was also discovered that the decomposition temperature was dependent on the GC carrier gas flow rate and, therefore, the residence time of the compounds in the transfer line/flow cell. For example, the measured decomposition temperature of nitroglycerine ranged from 222 °C to 253 °C across four flow rates. Tracking the appearance/disappearance of decomposition products across this temperature range indicated that NO, CO, and H2CO are final decomposition products while O2 and H2O are intermediate products. The decomposition temperatures for all explosives were highly correlated to similar decomposition measurements taken by differential scanning calorimetry (DSC) (r = 0.91) and thermal gravimetric analysis (TGA) (r = 0.90-0.98). In addition, the decomposition temperatures for all explosives were negatively correlated to the heat of explosion at constant volume (r = -0.68) and strongly positively correlated to the oxygen balance (r = 0.92).
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Affiliation(s)
- Courtney A Cruse
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis (IUPUI), 402 North Blackford Street, LD326, Indianapolis, IN, 46202, USA
| | - John V Goodpaster
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis (IUPUI), 402 North Blackford Street, LD326, Indianapolis, IN, 46202, USA; Forensic and Investigative Sciences Program, Indiana University-Purdue University Indianapolis (IUPUI), 402 North Blackford Street, LD326, Indianapolis, IN, 46202, USA.
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10
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Roberson ZR, Goodpaster JV. Optimization of the qualitative and quantitative analysis of cocaine and other drugs of abuse via gas chromatography - Vacuum ultraviolet spectrophotometry (GC - VUV). Talanta 2021; 222:121461. [PMID: 33167202 DOI: 10.1016/j.talanta.2020.121461] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 07/23/2020] [Accepted: 07/24/2020] [Indexed: 12/21/2022]
Abstract
Gas Chromatography-Vacuum UV Spectroscopy (GC-VUV) has seen increased attention in many areas, however, a statistical optimization of VUV method parameters has not been published. This article presents the first statistical optimization of parameters influencing analytes such as cocaine in the VUV flow-cell. Flow-cell temperature, make-up gas pressure, and carrier gas flow rate from the GC were examined and optimized for the detection of controlled substances. The accuracy, precision, linearity, and optimized detection limits for drugs such as cocaine (98.5%, 1.2%, 0.9998, 1.5 ng), heroin (99.3%, 0.94%, 0.9998, 2.0 ng), and fentanyl (98.5%, 1.7%, 0.9752, 9.7 ng) are reported. In general, the limits of detection for cocaine, heroin, fentanyl, and methamphetamine after optimization were comparable to gas chromatography-mass spectrometry (GC-MS) in "scan mode", which had detection limits of 1.1-38 ng on column. The VUV absorption spectra of cocaine, PCP, lorazepam, and HU-210 are also reported. And three samples of "real world" cocaine are analyzed to demonstrate applicability to forensic drug analysis.
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Affiliation(s)
- Zackery R Roberson
- Department of Chemistry and Chemical Biology, Indiana University Purdue University Indianapolis, 402 North Blackford St., LD326, Indianapolis, IN, 46202, United States
| | - John V Goodpaster
- Department of Chemistry and Chemical Biology, Indiana University Purdue University Indianapolis, 402 North Blackford St., LD326, Indianapolis, IN, 46202, United States; Forensic and Investigative Sciences Program, Indiana University Purdue University Indianapolis, 402 North Blackford St., LD326, Indianapolis, IN, 46202, United States.
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11
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Cruse CA, Pu J, Goodpaster JV. Identifying Thermal Decomposition Products of Nitrate Ester Explosives Using Gas Chromatography-Vacuum Ultraviolet Spectroscopy: An Experimental and Computational Study. APPLIED SPECTROSCOPY 2020; 74:1486-1495. [PMID: 32192365 DOI: 10.1177/0003702820915506] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Analysis of nitrate ester explosives (e.g., nitroglycerine) using gas chromatography-vacuum ultraviolet spectroscopy (GC-VUV) results in their thermal decomposition into nitric oxide, water, carbon monoxide, oxygen, and formaldehyde. These decomposition products exhibit highly structured spectra in the VUV that is not seen in larger molecules. Computational analysis using time-dependent density functional theory (TDDFT) was utilized to investigate the excited states and vibronic transitions of these decomposition products. The experimental and computational results are compared with those in previous literature using synchrotron spectroscopy, electron energy loss spectroscopy (EELS), photoabsorption spectroscopy, and other computational excited state methods. It was determined that a benchtop GC-VUV detector gives comparable results to those previously reported, and TDDFT could predict vibronic spacing and model molecular orbital diagrams.
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Affiliation(s)
- Courtney A Cruse
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis (IUPUI), Indianapolis, USA
| | - Jingzhi Pu
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis (IUPUI), Indianapolis, USA
| | - John V Goodpaster
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis (IUPUI), Indianapolis, USA
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12
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Advanced gas chromatography and mass spectrometry technologies for fatty acids and triacylglycerols analysis. Trends Analyt Chem 2020. [DOI: 10.1016/j.trac.2020.115957] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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13
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Li MWH, Huang X, Zhu H, Kurabayashi K, Fan X. Microfabricated ionic liquid column for separations in dry air. J Chromatogr A 2020; 1620:461002. [DOI: 10.1016/j.chroma.2020.461002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Revised: 02/25/2020] [Accepted: 02/26/2020] [Indexed: 01/09/2023]
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14
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Efficiency of capillary GC columns based on phosphonium ionic liquids. J Chromatogr A 2020; 1622:461127. [PMID: 32331778 DOI: 10.1016/j.chroma.2020.461127] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 04/09/2020] [Accepted: 04/12/2020] [Indexed: 11/24/2022]
Abstract
Gas chromatographic columns based on ionic liquids (ILs) are very promising since the selectivity of these columns can be tuned by both the cation and the anion chemical nature. In this paper, efficiencies of capillary columns based on four phosphonium ionic liquids were studied. The performance of seven columns containing the cation trihexyl(tetradecyl)phosphonium and the anions bromide, chloride, and bis(trifluoromethylsulfonyl)imide was evaluated by measuring the solute band broadening as a function of gas velocities at three temperatures. Hence, classical height equivalent to a theoretical plate (H) against gas velocity (u) plots corresponding to those columns were generated and the data were fitted to the Golay-Guiochon equation with the aim of seeking the optimum conditions to be operated each of them. Band broadening at practical gas velocities is mainly due to poor mass transfer properties of solutes in the (viscous) liquid phases, which limits the achieved efficiencies. These H/u plots proved to be necessary to characterize the column quality at a given temperature, to interpret the band broadening phenomena and thus, to establish the lower temperature limits and the expected plate counts at that temperature.
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15
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Mao JX, Walsh P, Kroll P, Schug KA. Simulation of Vacuum Ultraviolet Absorption Spectra: Paraffin, Isoparaffin, Olefin, Naphthene, and Aromatic Hydrocarbon Class Compounds. APPLIED SPECTROSCOPY 2020; 74:72-80. [PMID: 31517520 DOI: 10.1177/0003702819875132] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The advent of a new vacuum ultraviolet (VUV) spectroscopic absorption detector for gas chromatography has enabled applications in many areas. Theoretical simulations of VUV spectra using computational chemistry can aid the new technique in situations where experimental spectra are unavailable. In this study, VUV spectral simulations of paraffin, isoparaffin, olefin, naphthene, and aromatic (PIONA) compounds using time-dependent density functional theory (TDDFT) methods were investigated. Important factors for the simulations, such as functionals/basis sets and formalism of oscillator strength calculations, were examined and parameters for future PIONA compound simulations were obtained by fitting computational results to experimental spectra. The simulations produced satisfactory correlations between experimental observations and theoretical calculations, and enabled potential analysis applications for complex higher distillate fuels, such as diesel fuel. Further improvement of the methods was proposed.
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Affiliation(s)
- James X Mao
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, USA
| | | | - Peter Kroll
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, USA
| | - Kevin A Schug
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, USA
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16
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Lelevic A, Souchon V, Moreaud M, Lorentz C, Geantet C. Gas chromatography vacuum ultraviolet spectroscopy: A review. J Sep Sci 2019; 43:150-173. [PMID: 31750981 DOI: 10.1002/jssc.201900770] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 11/13/2019] [Accepted: 11/15/2019] [Indexed: 11/12/2022]
Abstract
Accelerated technological progress and increased complexity of interrogated matrices imposes a demand for fast, powerful, and resolutive analysis techniques. Gas chromatography has been for a long time a 'go-to' technique for the analysis of mixtures of volatile and semi-volatile compounds. Coupling of the several dimensions of gas chromatography separation has allowed to access a realm of improved separations in the terms of increased separation power and detection sensitivity. Especially comprehensive separations offer an insight into detailed sample composition for complex samples. Combining these advanced separation techniques with an informative detection system such as vacuum ultraviolet spectroscopy is therefore of great interest. Almost all molecules absorb the vacuum ultraviolet radiation and have distinct spectral features with compound classes exhibiting spectral signature similarities. Spectral information can be 'filtered' to extract the response in the most informative spectral ranges. Developed algorithms allow spectral mixture estimation of coeluting species. Vacuum ultraviolet detector follows Beer-Lambert law, with the possibility of calibrationless quantitation. The purpose of this article is to provide an overview of the features and specificities of gas chromatography-vacuum ultraviolet spectroscopy coupling which has gained interest since the recent introduction of a commercial vacuum ultraviolet detector. Potentials and limitations, relevant theoretical considerations, recent advances and applications are explored.
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Affiliation(s)
- Aleksandra Lelevic
- IFP Energies nouvelles, Rond-point de l'échangeur de Solaize BP 3, 69360, Solaize, France.,IRCELYON, UMR5256 CNRS-UCB Lyon 1, Villeurbanne Cedex, France
| | - Vincent Souchon
- IFP Energies nouvelles, Rond-point de l'échangeur de Solaize BP 3, 69360, Solaize, France
| | - Maxime Moreaud
- IFP Energies nouvelles, Rond-point de l'échangeur de Solaize BP 3, 69360, Solaize, France.,MINESParisTech, PSL-ResearchUniversity, CMM, Fontainebleau, France
| | - Chantal Lorentz
- IRCELYON, UMR5256 CNRS-UCB Lyon 1, Villeurbanne Cedex, France
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Gas chromatography-mass spectrometry-based analytical strategies for fatty acid analysis in biological samples. J Food Drug Anal 2019; 28:60-73. [PMID: 31883609 DOI: 10.1016/j.jfda.2019.10.003] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 10/21/2019] [Accepted: 10/30/2019] [Indexed: 02/07/2023] Open
Abstract
Fatty acids play critical roles in biological systems. Imbalances in fatty acids are related to a variety of diseases, which makes the measurement of fatty acids in biological samples important. Many analytical strategies have been developed to investigate fatty acids in various biological samples. Due to the structural diversity of fatty acids, many factors need to be considered when developing analytical methods including extraction methods, derivatization methods, column selections, and internal standard selections. This review focused on gas chromatography-mass spectrometry (GC-MS)-based methods. We reviewed several commonly used fatty acid extraction approaches, including liquid-liquid extraction and solid-phase microextraction. Moreover, both acid and base derivatization methods and other specially designed methods were comprehensively reviewed, and their strengths and limitations were discussed. Having good separation efficiency is essential to building an accurate and reliable GC-MS platform for fatty acid analysis. We reviewed the separation performance of different columns and discussed the application of multidimensional GC for improving separations. The selection of internal standards was also discussed. In the final section, we introduced several biomedical studies that measured fatty acid levels in different sample matrices and provided hints on the relationships between fatty acid imbalances and diseases.
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18
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Evaluation of different ionic liquid stationary phases for the analysis of carbohydrates by gas chromatography-mass spectrometry. Anal Bioanal Chem 2019; 411:7461-7472. [DOI: 10.1007/s00216-019-02118-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 08/21/2019] [Accepted: 09/02/2019] [Indexed: 10/25/2022]
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19
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20
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Santos IC, Smuts J, Crawford ML, Grant RP, Schug KA. Large-volume injection gas chromatography-vacuum ultraviolet spectroscopy for the qualitative and quantitative analysis of fatty acids in blood plasma. Anal Chim Acta 2019; 1053:169-177. [DOI: 10.1016/j.aca.2018.12.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Revised: 11/29/2018] [Accepted: 12/01/2018] [Indexed: 10/27/2022]
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21
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Dunkle MN, Pijcke P, Winniford B, Bellos G. Quantification of the composition of liquid hydrocarbon streams: Comparing the GC-VUV to DHA and GCxGC. J Chromatogr A 2019; 1587:239-246. [DOI: 10.1016/j.chroma.2018.12.026] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 11/29/2018] [Accepted: 12/12/2018] [Indexed: 10/27/2022]
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22
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Dillon GP, Wallace G, Yiannikouris A, Moran CA. An Accurate Assessment of Docosahexaenoic Acid in Laying Hen Serum for Regulatory Studies. ANALYTICAL CHEMISTRY INSIGHTS 2019; 13:1177390118815146. [PMID: 30636867 PMCID: PMC6318818 DOI: 10.1177/1177390118815146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 10/25/2018] [Indexed: 11/21/2022]
Abstract
Diets rich in omega-3 fatty acids (n-3 FA) have been associated with several
health benefits. With the increased interest in n-3 FA both scientifically and
societally, the accurate detection of such analytes has become increasingly
important. Recently, tandem mass spectrometry (MS/MS) with electrospray
ionization interface (ESI), hyphenated to both gas chromatography (GC) and
liquid chromatography (LC), has become a valuable tool in the detection of
docosahexaenoic acid (DHA). Liquid chromatography-electrospray ionization
interface-tandem mass spectrometry methods have been developed for the
determination of DHA in canine and poultry species. The objective of this
article is to investigate whether LC-ESI-MS/MS is fit for purpose for the
determination of DHA in laying hen serum. The disclosure of this work will be
beneficial for researchers investigating poultry enrichment for regulatory and
toxicological studies. The method was found to be linear over the range.
Precision and accuracy results met acceptance criteria and the Limit of
Quantitation (LOQ) was established as 1 µg/mL. Recoveries of DHA were obtained
for quality control samples and stability studies were performed. The results of
the verification study complimented those of the validation study. In summation,
the method was established as fit for purpose for measuring total DHA in laying
hen serum.
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Affiliation(s)
- Gerald Patrick Dillon
- Gerald Patrick Dillon, Regulatory Affairs Dept., Alltech Ireland, Sarney, Summerhill Road, Dunboyne, Co. Meath A86 X006, Ireland
| | - Geoff Wallace
- Geoff Wallace, LGC, Newmarket Road, Fordham, Cambridgeshire, CB7 5WW, United Kingdom
| | - Alexandros Yiannikouris
- Alexandros Yiannikouris, Research Department, Alltech Inc., Nicholasville, Kentucky 40356, USA
| | - Colm Anthony Moran
- Colm Anthony Moran, Regulatory Affairs Dept., Alltech SARL, Rue Charles Amand, 14500 Vire, France
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23
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Zheng J, Huang C, Wang S. Challenging pharmaceutical analyses by gas chromatography with vacuum ultraviolet detection. J Chromatogr A 2018; 1567:185-190. [DOI: 10.1016/j.chroma.2018.06.064] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 06/25/2018] [Accepted: 06/26/2018] [Indexed: 11/26/2022]
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24
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Bazina N, He J. Analysis of fatty acid profiles of free fatty acids generated in deep-frying process. JOURNAL OF FOOD SCIENCE AND TECHNOLOGY 2018; 55:3085-3092. [PMID: 30065418 PMCID: PMC6045989 DOI: 10.1007/s13197-018-3232-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Revised: 05/07/2018] [Accepted: 05/10/2018] [Indexed: 01/17/2023]
Abstract
During the deep fat food frying process, the frying media, oil, continuously degenerates when exposed to high temperature, oxygen and moisture. This leads to physical and chemical changes including the formation of hydrolysis products such as free fatty acids (FFAs) which are associated with undesirable darkening in colour, off-flavouring and a lowering of the smoke point. This study was aiming to develop a method capable of identifying and quantifying individual free fatty acids within oil using a small sample size (100 mg of oil). We used liquid/liquid extraction technique to separate FFAs from the rest of the oil followed by esterification using boron trifluoride (BF3) and then gas chromatography analysis. Various extraction conditions were tested. A mixture of 0.02 M phosphate buffer at pH 12 and acetonitrile at solvent: buffer ratio larger than 2:1 showed the highest efficiency in extraction of FFAs. The method was capable of producing accurate fatty acid profiles of FFAs and showed good precision on medium rancidity oil samples. It also captured the differences induced by adding free fatty acids to samples. An interesting discrepancy was found between the new method and the traditional titration method in terms of overall FFA content, which suggests further optimisation and investigation are required.
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Affiliation(s)
- Naser Bazina
- School of Science and Engineering, Teesside University, Middlesbrough, TS16 0HY UK
| | - Jibin He
- School of Science and Engineering, Teesside University, Middlesbrough, TS16 0HY UK
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25
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Analysis of bacterial FAMEs using gas chromatography – vacuum ultraviolet spectroscopy for the identification and discrimination of bacteria. Talanta 2018; 182:536-543. [DOI: 10.1016/j.talanta.2018.01.074] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2017] [Revised: 01/23/2018] [Accepted: 01/29/2018] [Indexed: 11/18/2022]
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26
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Waktola HD, Mjøs SA. Chromatographic efficiency of polar capillary columns applied for the analysis of fatty acid methyl esters by gas chromatography. J Sep Sci 2018; 41:1582-1592. [PMID: 29314609 DOI: 10.1002/jssc.201700908] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 11/21/2017] [Accepted: 12/12/2017] [Indexed: 11/11/2022]
Abstract
The chromatographic efficiency that could be achieved in temperature-programmed gas chromatography was compared for four capillary columns that are typically applied for analysis of fatty acid methyl esters (FAME). Three different carrier gases, hydrogen, helium and nitrogen, were applied. For each experiment, the carrier gas velocities and the temperature rates were varied with a full 9 × 3 design, with nine levels on the carrier gas velocity and temperature rates of 1, 2 or 3°C/min. Response surface methodology was used to create models of chromatographic efficiency as a function of temperature rate and carrier gas velocity. The chromatographic efficiency was defined as the inverse of peak widths measured in retention index units. The final results were standardized so that the efficiencies that could be achieved within a certain time frame, defined by the retention time of the last compound in the chromatogram, could be compared. The results show that there were clear differences in the efficiencies that could be achieved with the different columns and that the efficiency decreased with increasing polarity of the stationary phase. The differences can be explained by higher resistance to mass transfer in the stationary phase in the most polar columns.
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Affiliation(s)
| | - Svein A Mjøs
- Department of Chemistry, University of Bergen, Bergen, Norway
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27
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Dillon GP, Keegan JD, Wallace G, Yiannikouris A, Moran CA. The validation & verification of an LC/MS method for the determination of total docosahexaenoic acid concentrations in canine blood serum. Regul Toxicol Pharmacol 2018; 95:198-203. [PMID: 29577958 DOI: 10.1016/j.yrtph.2018.03.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 03/19/2018] [Accepted: 03/21/2018] [Indexed: 11/26/2022]
Abstract
Docosahexaenoic acid (DHA), is an omega 3 fatty acid (n-3 FA) that has been shown to play a role in canine growth and physiological integrity and improvements in skin and coat condition. However, potential adverse effects of n-3 FA specifically, impaired cellular immunity has been observed in dogs fed diets with elevated levels of n-3 FA. As such, a safe upper limit (SUL) for total n-3 FAs (DHA and EPA) in dogs has been established. Considering this SUL, sensitive methods detecting DHA in blood serum as a biomarker when conducting n-3 FA supplementation trials involving dogs are required. In this study, an LC-ESI-MS/MS method of DHA detection in dog serum was validated and verified. Recovery of DHA was optimized and parallelism tests were conducted with spiked samples demonstrating that the serum matrix did not interfere with quantitation. The stability of DHA in serum was also investigated, with -80 °C considered suitable when storing samples for up to six months. The method was linear over a calibration range of 1-500 μg/mL and precision and accuracy were found to meet the requirements for validation. This method was verified in an alternative laboratory using a different analytical system and operator, with the results meeting the criteria for verification.
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Affiliation(s)
| | - Jason D Keegan
- Alltech Ireland, Sarney, Summerhill Road, Dunboyne, Co Meath, Ireland
| | | | | | - Colm Anthony Moran
- Regulatory Affairs Department, Alltech SARL, Rue Charles Amand, 14500 Vire, France
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28
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Dillon GP, Wallace G, Yiannikouris A, Moran CA. Validation and Verification of a Liquid Chromatography-Mass Spectrometry Method for the Determination of Total Docosahexaenoic Acid in Pig Serum. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:2008-2014. [PMID: 29392935 DOI: 10.1021/acs.jafc.7b04791] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The paper presents the validation and verification of an analytical method for the determination of total docosahexaenoic acid (DHA) in pig serum by liquid chromatography-electrospray ionization-tandem mass spectrometry. The characteristics studied during the validation included precision and accuracy, limit of quantitation (LOQ), selectivity, calibration range and linearity, parallelism, and stability. A separate verification study was also performed. The method was linear over the range. Precision and accuracy met acceptance criteria at all levels, and the LOQ was determined as 1 μg/mL. Parallelism experiments were conducted to show that there was no bias introduced in using a surrogate matrix to quantify DHA. Recoveries of free DHA were obtained for quality control samples, and stability studies were conducted over 1, 7, 31, and 180 days. The results of the verification study were in line with the validation study, and in conclusion, the method was deemed fit for purpose for measuring total DHA in pig serum.
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Affiliation(s)
- Gerald Patrick Dillon
- Alltech Biotechnology , Sarney, Summerhill Road, Dunboyne, Co. Meath A86 X006, Ireland
| | - Geoff Wallace
- LGC , Newmarket Road, Fordham, Cambridgeshire, CB7 5WW, United Kingdom
| | - Alexandros Yiannikouris
- Research Department, Alltech , Helioparc Pau Pyrenees, 3031 Catnip Hill Road, Nicholasville, Kentucky 40356, USA
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29
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Ionic liquid phases with comprehensive two-dimensional gas chromatography of fatty acid methyl esters. Anal Bioanal Chem 2018; 410:4669-4677. [DOI: 10.1007/s00216-018-0944-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 01/26/2018] [Accepted: 02/05/2018] [Indexed: 10/18/2022]
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30
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Zavahir JS, Nolvachai Y, Marriott PJ. Molecular spectroscopy – Information rich detection for gas chromatography. Trends Analyt Chem 2018. [DOI: 10.1016/j.trac.2017.11.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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31
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Branched-chain dicationic ionic liquids for fatty acid methyl ester assessment by gas chromatography. Anal Bioanal Chem 2017; 410:4633-4643. [DOI: 10.1007/s00216-017-0722-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 10/12/2017] [Accepted: 10/23/2017] [Indexed: 10/18/2022]
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32
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Lenca N, Poole CF. A system map for the ionic liquid stationary phase 1,12-di(tripropylphosphonium)dodecane bis(trifluoromethylsulfonyl)imide for gas chromatography. J Chromatogr A 2017; 1525:138-144. [DOI: 10.1016/j.chroma.2017.10.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Revised: 03/15/2017] [Accepted: 10/06/2017] [Indexed: 10/18/2022]
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33
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Schenk J, Nagy G, Pohl NL, Leghissa A, Smuts J, Schug KA. Identification and deconvolution of carbohydrates with gas chromatography-vacuum ultraviolet spectroscopy. J Chromatogr A 2017; 1513:210-221. [DOI: 10.1016/j.chroma.2017.07.052] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2017] [Revised: 06/28/2017] [Accepted: 07/16/2017] [Indexed: 12/31/2022]
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34
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Santos IC, Smuts J, Schug KA. Rapid Profiling and Authentication of Vanilla Extracts Using Gas Chromatography-Vacuum Ultraviolet Spectroscopy. FOOD ANAL METHOD 2017. [DOI: 10.1007/s12161-017-0976-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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35
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Skultety L, Frycak P, Qiu C, Smuts J, Shear-Laude L, Lemr K, Mao JX, Kroll P, Schug KA, Szewczak A, Vaught C, Lurie I, Havlicek V. Resolution of isomeric new designer stimulants using gas chromatography - Vacuum ultraviolet spectroscopy and theoretical computations. Anal Chim Acta 2017; 971:55-67. [PMID: 28456284 DOI: 10.1016/j.aca.2017.03.023] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 03/10/2017] [Accepted: 03/12/2017] [Indexed: 11/29/2022]
Abstract
Distinguishing isomeric representatives of "bath salts", "plant food", "spice", or "legal high" remains a challenge for analytical chemistry. In this work, we used vacuum ultraviolet spectroscopy combined with gas chromatography to address this issue on a set of forty-three designer drugs. All compounds, including many isomers, returned differentiable vacuum ultraviolet/ultraviolet spectra. The pair of 3- and 4-fluoromethcathinones (m/z 181.0903), as well as the methoxetamine/meperidine/ethylphenidate (m/z 247.1572) triad, provided very distinctive vacuum ultraviolet spectral features. On the contrary, spectra of 4-methylethcathinone, 4-ethylmethcathinone, 3,4-dimethylmethcathinone triad (m/z 191.1310) displayed much higher similarities. Their resolution was possible only if pure standards were probed. A similar situation occurred with the ethylone and butylone pair (m/z 221.1052). On the other hand, majority of forty-three drugs was successfully separated by gas chromatography. The detection limits for all the drug standards were in the 2-4 ng range (on-column amount), which is sufficient for determinations of seized drugs during forensics analysis. Further, state-of-the-art time-dependent density functional theory was evaluated for computation of theoretical absorption spectra in the 125-240 nm range as a complementary tool.
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Affiliation(s)
- Ludovit Skultety
- Institute of Microbiology, v.v.i., The Czech Academy of Sciences, Prague, Czech Republic; Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Petr Frycak
- Regional Centre of Advanced Technologies and Materials, Department of Analytical Chemistry, Faculty of Science of Palacky University in Olomouc, Olomouc, Czech Republic
| | - Changling Qiu
- Department of Chemistry & Biochemistry, The University of Texas at Arlington, Arlington, TX, USA
| | | | | | - Karel Lemr
- Institute of Microbiology, v.v.i., The Czech Academy of Sciences, Prague, Czech Republic; Regional Centre of Advanced Technologies and Materials, Department of Analytical Chemistry, Faculty of Science of Palacky University in Olomouc, Olomouc, Czech Republic
| | - James X Mao
- Department of Chemistry & Biochemistry, The University of Texas at Arlington, Arlington, TX, USA
| | - Peter Kroll
- Department of Chemistry & Biochemistry, The University of Texas at Arlington, Arlington, TX, USA
| | - Kevin A Schug
- Department of Chemistry & Biochemistry, The University of Texas at Arlington, Arlington, TX, USA
| | - Angelica Szewczak
- Department of Forensic Science, George Washington University, Washington, DC, USA
| | - Cory Vaught
- Department of Forensic Science, George Washington University, Washington, DC, USA
| | - Ira Lurie
- Department of Forensic Science, George Washington University, Washington, DC, USA
| | - Vladimir Havlicek
- Institute of Microbiology, v.v.i., The Czech Academy of Sciences, Prague, Czech Republic; Regional Centre of Advanced Technologies and Materials, Department of Analytical Chemistry, Faculty of Science of Palacky University in Olomouc, Olomouc, Czech Republic.
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36
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Qiu C, Cochran J, Smuts J, Walsh P, Schug KA. Gas chromatography-vacuum ultraviolet detection for classification and speciation of polychlorinated biphenyls in industrial mixtures. J Chromatogr A 2017; 1490:191-200. [DOI: 10.1016/j.chroma.2017.02.031] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 02/13/2017] [Accepted: 02/14/2017] [Indexed: 11/28/2022]
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37
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Jonnada M, El Rassi GD, El Rassi Z. Selective precolumn derivatization of fatty acids with the fluorescent tag 6-aminoquinoline and their determination in some food samples by reversed-phase chromatography. Electrophoresis 2017; 38:1592-1601. [DOI: 10.1002/elps.201600544] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 01/17/2017] [Indexed: 11/05/2022]
Affiliation(s)
- Murthy Jonnada
- Department of Chemistry; Oklahoma State University; Stillwater OK USA
| | | | - Ziad El Rassi
- Department of Chemistry; Oklahoma State University; Stillwater OK USA
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38
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Senarath S, Yoshinaga K, Nagai T, Yoshida A, Beppu F, Jayasinghe C, Devadawson C, Gotoh N. Quantitative Analysis of the Distribution of cis-Eicosenoic Acid Positional Isomers in Marine Fishes from the Indian Ocean. J Oleo Sci 2017; 66:187-197. [PMID: 28100885 DOI: 10.5650/jos.ess16155] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
This study investigated the occurrence and distribution of cis-eicosenoic acid (c-20:1) positional isomers in fishes from the Indian Ocean and compared to those from the Pacific and Atlantic Ocean. Lipids were extracted from the edible part of the fish and then methylated. The eicosenoic acid methyl ester fraction was separated from total fatty acid methyl esters by reversed-phase HPLC and quantitatively analyzed using a GC-FID fitted with the SLB-IL111 highly polar GC column. c14-20:1 was used as an internal standard. The results indicated that the highest levels of c-20:1 positional isomers were found in fishes from the Pacific Ocean (saury, 166.95±12.4 mg/g of oil), followed by the Atlantic Ocean (capelin, 162.7±3.5 mg/g of oil), and lastly in fishes from the Indian Ocean (goatfish, 34.39 mg/g of oil). With only a few exceptions, the most abundant 20:1 positional isomer found in fishes of the Indian and Atlantic Ocean was the c11-20:1 isomer (>50%) followed by the c13-20:1 isomer (<25%). Unusually, the c7-20:1 isomer was predominantly found in a few fishes such as the tooth ponyfish, longface emperor, and commerson's sole. The c9, c5, and c15-20:1 isomers were the least occurring in fishes from the Indian and Atlantic Ocean. In contrast, the c9-20:1 isomer was the principal isomer identified in fishes from the Pacific Ocean. The results revealed that the content and distribution of c-20:1 positional isomers varied among fishes in different oceans. The data presented in the current study are the first to report on the distribution of c-20:1 positional isomers in fishes from the Indian Ocean.
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Affiliation(s)
- Samanthika Senarath
- Department of Food Science and Technology, Tokyo University of Marine Science and Technology
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39
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Qiu C, Smuts J, Schug KA. Analysis of terpenes and turpentines using gas chromatography with vacuum ultraviolet detection. J Sep Sci 2017; 40:869-877. [PMID: 27983761 DOI: 10.1002/jssc.201601019] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 11/09/2016] [Accepted: 11/27/2016] [Indexed: 12/20/2022]
Abstract
The separation and identification of natural mixtures of terpenes is challenging and laborious. A gas chromatographic method based on vacuum ultraviolet spectroscopic detection, which is characterized by full-scan absorption in the range of 125-240 nm, was developed and applied to analyze terpenes. In this study, the vacuum ultraviolet absorption spectra of 41 different standard terpenes were investigated and compared. The spectra were found to be highly featured and easily differentiated. Several commercial turpentine samples were analyzed and the vacuum ultraviolet detector demonstrated good specificity for qualitative identification of constituent terpenes. A total of 31 terpenes were detected in the four turpentine samples. α-Pinene was the predominant terpene ranging from 744.2 ± 9.7 to 917 ± 21 mg/mL. The other major constituents in the turpentines included β-pinene, δ-3-carene, camphene, and p-isopropyltoluene. Deconvolution of co-eluting signals of terpenes was achieved utilizing the data analysis software. The technique has been demonstrated to be a powerful tool for reliable and accurate qualitative and quantitative analysis of terpenes from complex natural mixtures.
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Affiliation(s)
- Changling Qiu
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX, 76019, USA
| | | | - Kevin A Schug
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX, 76019, USA
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40
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Fanali C, Micalizzi G, Dugo P, Mondello L. Ionic liquids as stationary phases for fatty acid analysis by gas chromatography. Analyst 2017; 142:4601-4612. [DOI: 10.1039/c7an01338h] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The present paper provides an overview of the application of ionic liquid (IL) columns for GC analysis of fatty acid methyl esters (FAMEs).
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Affiliation(s)
- C. Fanali
- Department of Medicine
- University Campus Bio-Medico of Rome
- 00128 Rome
- Italy
| | - G. Micalizzi
- Dipartimento di “Scienze Chimiche
- Biologiche
- Farmaceutiche ed Ambientali”
- University of Messina – Polo Annunziata
- 98168 Messina
| | - P. Dugo
- Department of Medicine
- University Campus Bio-Medico of Rome
- 00128 Rome
- Italy
- Dipartimento di “Scienze Chimiche
| | - L. Mondello
- Department of Medicine
- University Campus Bio-Medico of Rome
- 00128 Rome
- Italy
- Dipartimento di “Scienze Chimiche
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41
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Santos IC, Schug KA. Recent advances and applications of gas chromatography vacuum ultraviolet spectroscopy. J Sep Sci 2016; 40:138-151. [DOI: 10.1002/jssc.201601023] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 10/30/2016] [Accepted: 10/31/2016] [Indexed: 11/07/2022]
Affiliation(s)
- Inês C. Santos
- Department of Chemistry and Biochemistry; The University of Texas at Arlington; Arlington TX USA
| | - Kevin A. Schug
- Department of Chemistry and Biochemistry; The University of Texas at Arlington; Arlington TX USA
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42
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Walsh P, Garbalena M, Schug KA. Rapid Analysis and Time Interval Deconvolution for Comprehensive Fuel Compound Group Classification and Speciation Using Gas Chromatography–Vacuum Ultraviolet Spectroscopy. Anal Chem 2016; 88:11130-11138. [DOI: 10.1021/acs.analchem.6b03226] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Phillip Walsh
- VUV Analytics, Inc., Cedar Park, Texas 78613, United States
| | - Manuel Garbalena
- McKee Laboratory, Valero Energy Corporation, Sunray, Texas 79086, United States
| | - Kevin A. Schug
- Department
of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019, United States
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43
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Schenk J, Mao JX, Smuts J, Walsh P, Kroll P, Schug KA. Analysis and deconvolution of dimethylnaphthalene isomers using gas chromatography vacuum ultraviolet spectroscopy and theoretical computations. Anal Chim Acta 2016; 945:1-8. [PMID: 27968710 DOI: 10.1016/j.aca.2016.09.021] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 09/09/2016] [Accepted: 09/11/2016] [Indexed: 10/21/2022]
Abstract
An issue with most gas chromatographic detectors is their inability to deconvolve coeluting isomers. Dimethylnaphthalenes are a class of compounds that can be particularly difficult to speciate by gas chromatography - mass spectrometry analysis, because of their significant coelution and similar mass spectra. As an alternative, a vacuum ultraviolet spectroscopic detector paired with gas chromatography was used to study the systematic deconvolution of mixtures of coeluting isomers of dimethylnaphthalenes. Various ratio combinations of 75:25; 50:50; 25:75; 20:80; 10:90; 5:95; and 1:99 were prepared to test the accuracy, precision, and sensitivity of the detector for distinguishing overlapping isomers that had distinct, but very similar absorption spectra. It was found that, under reasonable injection conditions, all of the pairwise overlapping isomers tested could be deconvoluted up to nearly two orders of magnitude (up to 99:1) in relative abundance. These experimental deconvolution values were in agreement with theoretical covariance calculations performed for two of the dimethylnaphthalene isomers. Covariance calculations estimated high picogram detection limits for a minor isomer coeluting with low to mid-nanogram quantity of a more abundant isomer. Further characterization of the analytes was performed using density functional theory computations to compare theory with experimental measurements. Additionally, gas chromatography - vacuum ultraviolet spectroscopy was shown to be able to speciate dimethylnaphthalenes in jet and diesel fuel samples.
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Affiliation(s)
- Jamie Schenk
- Department of Chemistry & Biochemistry, The University of Texas at Arlington, Arlington, TX 76019, United States
| | - James X Mao
- Department of Chemistry & Biochemistry, The University of Texas at Arlington, Arlington, TX 76019, United States
| | - Jonathan Smuts
- VUV Analytics, Inc., Cedar Park, TX 78613, United States
| | - Phillip Walsh
- VUV Analytics, Inc., Cedar Park, TX 78613, United States
| | - Peter Kroll
- Department of Chemistry & Biochemistry, The University of Texas at Arlington, Arlington, TX 76019, United States
| | - Kevin A Schug
- Department of Chemistry & Biochemistry, The University of Texas at Arlington, Arlington, TX 76019, United States.
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