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Maw-rong Lee - One of the best experts on this subject based on the ideXlab platform.
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Determining leaching of bisphenol A from plastic containers by solid-phase microextraction and gas chromatography-mass spectrometry
Analytica Chimica Acta, 2005Co-Authors: Chia-min Chang, Chi-chi Chou, Maw-rong LeeAbstract:This study evaluates solid-phase microextraction (SPME) coupled with gas chromatography–mass spectrometry (GC–MS) to determine trace levels of bisphenol A in water and leached from plastic containers. The extraction using headspace post-Derivatization with bis(trimethylsilyl) trifluoroacetamide (BSTFA), containing 1% trimethylchlorosilane (TMCS) vapor, following SPME was compared with extraction without Derivatization. The SPME experimental procedures to extract bisphenol A in water were optimized with a relatively polar polyacrylate (PA)coated fiber, an extraction time of 50 min and desorption at 300 ◦ C for 2 min. Headspace Derivatization following SPME was performed using 7L of BSTFA with 1% TMCS at 65 ◦ C for 30 s. The precision was 5.2% without Derivatization and 9.0% headspace Derivatization. The detection limit was determined to be at the ng/L level. When SPME was used following headspace Derivatization, the detection limit was one order of magnitude better than that achieved without Derivatization. The results of this study reveal the adequacy of SPME–GC–MS method for analyzing bisphenol A leached from plastic containers. The concentrations of bisphenol A leached from plastic containers into water ranged from 0.7 to 78.5g/L. © 2005 Elsevier B.V. All rights reserved.
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Determining leaching of bisphenol A from plastic containers by solid-phase microextraction and gas chromatography–mass spectrometry
Analytica Chimica Acta, 2005Co-Authors: Chia-min Chang, Chi-chi Chou, Maw-rong LeeAbstract:This study evaluates solid-phase microextraction (SPME.) coupled with gas chromatography-mass spectrometry (GC-MS) to determine trace levels of bisphenol A in water and leached from plastic containers. The extraction using headspace post-Derivatization with bis(trimethylsilyl) trifluoroacetamide (BSTFA), containing 1% trimethylchlorosilane (TMCS) vapor, following SPME was compared with extraction without Derivatization. The SPME experimental procedures to extract bisphenol A in water were optimized with a relatively polar polyacrylate (PA)-coated fiber, an extraction time of 50 min and desorption at 300 degrees C for 2 min. Headspace Derivatization following SPME was performed using 7 mu L of BSTFA with 1% TMCS at 65 degrees C for 30s. The precision was 5.2% without Derivatization and 9.0% headspace Derivatization. The detection limit was determined to be at the ng/L level. When SPME was used following headspace Derivatization, the detection limit was one order of magnitude better than that achieved without Derivatization. The results of this study reveal the adequacy of SPME-GC-MS method for analyzing bisphenol A leached from plastic containers. The concentrations of bisphenol A leached from plastic containers into water ranged from 0.7 to 78.5 mu g/L. (c) 2005 Elsevier B.V. All rights reserved
Riin Rebane - One of the best experts on this subject based on the ideXlab platform.
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A systematic approach toward comparing electrospray ionization efficiencies of derivatized and non-derivatized amino acids and biogenic amines.
Journal of mass spectrometry : JMS, 2018Co-Authors: Artur Gornischeff, Jaanus Liigand, Riin RebaneAbstract:Ionization efficiency (IE) in mass spectrometry (MS) has been studied for many different compounds, and different IE scales have been constructed in order to quantitatively characterize IE. In the case of MS, Derivatization has been used to increase the sensitivity of the method and to lower the limits of detection. However, the influence of Derivatization on IE across different compounds and different Derivatization reagents has not been thoroughly researched, so that practitioners do not have information on the IE-enhancing abilities of different Derivatization reagents. Moreover, measuring IE via direct infusion of compounds cannot be considered fully adequate. Since derivatized compounds are in complex mixtures, a chromatographic method is needed to separate these compounds to minimize potential matrix effects. In this work, an IE measurement system with a chromatographic column was developed for mainly amino acids and some biogenic amines. IE measurements with liquid chromatography electrospray ionization mass spectrometry (LC/ESI/MS) were carried out, and IE scales were constructed with a calibration curve for compounds with and without Derivatization reagent diethyl ethoxymethylenemalonate. Additionally, eluent composition effects on ionization were investigated. Results showed that Derivatization increases IE for most of the compounds (by average 0.9 and up to 2-2.5 logIE units) and derivatized compounds have more similar logIE values than without Derivatization. Mobile phase composition effects on ionization efficiencies were negligible. It was also noted that the use of chromatographic separation instead of flow injection mode slightly increases IE. In this work, for the first time, IE enhancement of Derivatization reagents was quantified under real LC/ESI/MS conditions and obtained logIE values of derivatized compounds were linked with the existing scale.
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Matrix influence on Derivatization and ionization processes during selenoamino acid liquid chromatography electrospray ionization mass spectrometric analysis.
Journal of chromatography. B Analytical technologies in the biomedical and life sciences, 2014Co-Authors: Riin Rebane, Maarja-liisa Oldekop, Koit HerodesAbstract:Considering the importance of Derivatization in LC/ESI/MS analysis, the objective of this work was to develop a method for evaluation of matrix effect that would discriminate between matrix effect due to the Derivatization reaction yield and from the ESI. Four Derivatization reagents (TAHS, DEEMM, DNS, FMOC-Cl) were studied with respect to matrix effects using two selenoamino acids and onion matrix as model system. A novel method for assessing matrix effects of LC/ESI/MS analyses involving Derivatization is proposed, named herein post-Derivatization spiking, that allows evaluating effect of matrix on ESI ionization without Derivatization reaction yield contribution. The proposed post-Derivatization spiking method allowed to demonstrate that the reason of reduced analytical signal can be signal suppression in ESI (as in case of DNS derivatives with matrix effects 38-99%), alteration of Derivatization reaction yield (TAHS, matrix effects 92-113%, but reaction yields 20-50%) or both (FMOC-Cl, matrix effects 28-88% and reaction yields 50-70%). In case of DEEMM derivatives, matrix reduces reaction yield but enhances ESI/MS signal. A method for matrix effect evaluation was developed. It was also confirmed that matrix effects can be reduced by dilution.
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Comparison of amino acid Derivatization reagents for LC-ESI-MS analysis. Introducing a novel phosphazene-based Derivatization reagent.
Journal of chromatography. B Analytical technologies in the biomedical and life sciences, 2012Co-Authors: Riin Rebane, Maarja-liisa Oldekop, Koit HerodesAbstract:Abstract Amino acid analysis with high performance liquid chromatography with electrospray ionization mass spectrometry (LC–ESI-MS) is an emerging method. For more sensitive analysis, Derivatization is used and next to commercially available Derivatization reagents such as dansyl chloride (DNS), 9-fluorenylmethyl chloroformate (FMOC-Cl) and diethyl ethoxymethylenemalonate (DEEMM), new Derivatization reagents are designed specially for LC–ESI-MS, like p-N,N,N-trimethylammonioanilyl N′-hydroxysuccinimidyl carbamate iodide (TAHS) which provides very low limits of detection. In this work, a novel phosphazene based Derivatization reagent (FOSF) that provides comparable limits of quantitation (LoQ) to TAHS is introduced. Moreover, a thorough comparison between FOSF, TAHS, DNS, FMOC-Cl and DEEMM is carried out for 7 different amino acids – Arg, Asp, Gly, β-Ala, Pro, Trp and Phe. This is a first time that thorough comparison is carried out on the same instrument for amino acid Derivatization reagents. Results on the same instrument for five amino acid Derivatization reagents show that novel reagents are sensitive with LoQ values around 80 fmol but have disadvantages such as problematic chromatographic separation. Next to novel reagents, DEEMM offers very good LoQ-s (average of 150 fmol) and wide dynamic linear range.
Koit Herodes - One of the best experts on this subject based on the ideXlab platform.
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Comparison of Derivatization methods for the quantitative gas chromatographic analysis of oils
Analytical Methods, 2019Co-Authors: Eliise Tammekivi, Signe Vahur, Ott Kekišev, Inez D. Van Der Werf, Lauri Toom, Koit Herodes, Ivo LeitoAbstract:The determination of fatty acid composition using quantitative gas chromatographic (GC) analysis is a common method of characterizing fats and oils. A wide variety of Derivatization methods have been developed to enable the GC analysis of non-volatile oil components. However, there has been no systematic comparison of these Derivatization procedures in truly quantitative terms, i.e. with absolute amounts of fatty acids, not just ratios. In this paper, for the first time, a comprehensive quantitative comparison of four Derivatization methods is presented: (1) m-(trifluoromethyl)phenyltrimethylammonium hydroxide (TMTFTH) methylation, (2) two-step Derivatization with sodium ethoxide (NaOEt) and N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA), (3) two-step Derivatization with KOH and BSTFA and (4) acid-catalyzed methylation (ACM). The comparison of the results obtained with both a mass spectrometric (MS) detector and a flame ionization detector (FID) is mainly based on Derivatization efficiency (absolute quantification) and intermediate precision (within-lab reproducibility) over several weeks. The overall results indicate that out of the four examined methods the TMTFTH Derivatization was the least work-intensive and the most accurate – both in terms of reproducibility and Derivatization efficiency.
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Matrix influence on Derivatization and ionization processes during selenoamino acid liquid chromatography electrospray ionization mass spectrometric analysis.
Journal of chromatography. B Analytical technologies in the biomedical and life sciences, 2014Co-Authors: Riin Rebane, Maarja-liisa Oldekop, Koit HerodesAbstract:Considering the importance of Derivatization in LC/ESI/MS analysis, the objective of this work was to develop a method for evaluation of matrix effect that would discriminate between matrix effect due to the Derivatization reaction yield and from the ESI. Four Derivatization reagents (TAHS, DEEMM, DNS, FMOC-Cl) were studied with respect to matrix effects using two selenoamino acids and onion matrix as model system. A novel method for assessing matrix effects of LC/ESI/MS analyses involving Derivatization is proposed, named herein post-Derivatization spiking, that allows evaluating effect of matrix on ESI ionization without Derivatization reaction yield contribution. The proposed post-Derivatization spiking method allowed to demonstrate that the reason of reduced analytical signal can be signal suppression in ESI (as in case of DNS derivatives with matrix effects 38-99%), alteration of Derivatization reaction yield (TAHS, matrix effects 92-113%, but reaction yields 20-50%) or both (FMOC-Cl, matrix effects 28-88% and reaction yields 50-70%). In case of DEEMM derivatives, matrix reduces reaction yield but enhances ESI/MS signal. A method for matrix effect evaluation was developed. It was also confirmed that matrix effects can be reduced by dilution.
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Comparison of amino acid Derivatization reagents for LC-ESI-MS analysis. Introducing a novel phosphazene-based Derivatization reagent.
Journal of chromatography. B Analytical technologies in the biomedical and life sciences, 2012Co-Authors: Riin Rebane, Maarja-liisa Oldekop, Koit HerodesAbstract:Abstract Amino acid analysis with high performance liquid chromatography with electrospray ionization mass spectrometry (LC–ESI-MS) is an emerging method. For more sensitive analysis, Derivatization is used and next to commercially available Derivatization reagents such as dansyl chloride (DNS), 9-fluorenylmethyl chloroformate (FMOC-Cl) and diethyl ethoxymethylenemalonate (DEEMM), new Derivatization reagents are designed specially for LC–ESI-MS, like p-N,N,N-trimethylammonioanilyl N′-hydroxysuccinimidyl carbamate iodide (TAHS) which provides very low limits of detection. In this work, a novel phosphazene based Derivatization reagent (FOSF) that provides comparable limits of quantitation (LoQ) to TAHS is introduced. Moreover, a thorough comparison between FOSF, TAHS, DNS, FMOC-Cl and DEEMM is carried out for 7 different amino acids – Arg, Asp, Gly, β-Ala, Pro, Trp and Phe. This is a first time that thorough comparison is carried out on the same instrument for amino acid Derivatization reagents. Results on the same instrument for five amino acid Derivatization reagents show that novel reagents are sensitive with LoQ values around 80 fmol but have disadvantages such as problematic chromatographic separation. Next to novel reagents, DEEMM offers very good LoQ-s (average of 150 fmol) and wide dynamic linear range.
Chia-min Chang - One of the best experts on this subject based on the ideXlab platform.
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Determining leaching of bisphenol A from plastic containers by solid-phase microextraction and gas chromatography-mass spectrometry
Analytica Chimica Acta, 2005Co-Authors: Chia-min Chang, Chi-chi Chou, Maw-rong LeeAbstract:This study evaluates solid-phase microextraction (SPME) coupled with gas chromatography–mass spectrometry (GC–MS) to determine trace levels of bisphenol A in water and leached from plastic containers. The extraction using headspace post-Derivatization with bis(trimethylsilyl) trifluoroacetamide (BSTFA), containing 1% trimethylchlorosilane (TMCS) vapor, following SPME was compared with extraction without Derivatization. The SPME experimental procedures to extract bisphenol A in water were optimized with a relatively polar polyacrylate (PA)coated fiber, an extraction time of 50 min and desorption at 300 ◦ C for 2 min. Headspace Derivatization following SPME was performed using 7L of BSTFA with 1% TMCS at 65 ◦ C for 30 s. The precision was 5.2% without Derivatization and 9.0% headspace Derivatization. The detection limit was determined to be at the ng/L level. When SPME was used following headspace Derivatization, the detection limit was one order of magnitude better than that achieved without Derivatization. The results of this study reveal the adequacy of SPME–GC–MS method for analyzing bisphenol A leached from plastic containers. The concentrations of bisphenol A leached from plastic containers into water ranged from 0.7 to 78.5g/L. © 2005 Elsevier B.V. All rights reserved.
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Determining leaching of bisphenol A from plastic containers by solid-phase microextraction and gas chromatography–mass spectrometry
Analytica Chimica Acta, 2005Co-Authors: Chia-min Chang, Chi-chi Chou, Maw-rong LeeAbstract:This study evaluates solid-phase microextraction (SPME.) coupled with gas chromatography-mass spectrometry (GC-MS) to determine trace levels of bisphenol A in water and leached from plastic containers. The extraction using headspace post-Derivatization with bis(trimethylsilyl) trifluoroacetamide (BSTFA), containing 1% trimethylchlorosilane (TMCS) vapor, following SPME was compared with extraction without Derivatization. The SPME experimental procedures to extract bisphenol A in water were optimized with a relatively polar polyacrylate (PA)-coated fiber, an extraction time of 50 min and desorption at 300 degrees C for 2 min. Headspace Derivatization following SPME was performed using 7 mu L of BSTFA with 1% TMCS at 65 degrees C for 30s. The precision was 5.2% without Derivatization and 9.0% headspace Derivatization. The detection limit was determined to be at the ng/L level. When SPME was used following headspace Derivatization, the detection limit was one order of magnitude better than that achieved without Derivatization. The results of this study reveal the adequacy of SPME-GC-MS method for analyzing bisphenol A leached from plastic containers. The concentrations of bisphenol A leached from plastic containers into water ranged from 0.7 to 78.5 mu g/L. (c) 2005 Elsevier B.V. All rights reserved
Xiangmin Zhang - One of the best experts on this subject based on the ideXlab platform.
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Headspace single-drop microextraction with in-drop Derivatization for aldehyde analysis.
Journal of separation science, 2005Co-Authors: Chunhui Deng, Ning Yao, Xiangmin ZhangAbstract:A new technique, headspace single-drop microextraction (HS-SDME) with in-drop Derivatization, was developed. Its feasibility was demonstrated by analysis of the model compounds, aldehydes in water. A hanging microliter drop of solvent containing the Derivatization agent of O-2,3,4,5,6-(pentaflurobenzyl)hydroxylamine hydrochloride (PFBHA) was shown to be an excellent extraction, concentration, and Derivatization medium for headspace analysis of aldehydes by GC-MS. Using the microdrop solvent with PFBHA, acetaldehyde, propanal, butanal, hexanal, and heptanal in water were headspace extracted and simultaneously derivatized. The formed oximes in the microdrop were analyzed by GC-MS. HS-SDME and in-drop Derivatization parameters (extraction solvent, extraction temperature, extraction time, stirring rate microdrop volume, and the headspace volume) and the method validations (linearity, precision, detection limit, and recovery) were studied. Compared to liquid-liquid extraction and solid-phase microextraction, HS-SDME with in-drop Derivatization is a simple, rapid, convenient, and inexpensive sample technique.
