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Ken-ichi Kuroda - One of the best experts on this subject based on the ideXlab platform.
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Simultaneous Analysis of Cinnamyl Alcohol and Aldehyde-end Groups by Analytical Pyrolysis-silylation
2005Co-Authors: Akiko Nakagawa-izumi, Ken-ichi KurodaAbstract:Pyrolysis-gas chromatography in the presence of N-O-bis(trimethylsilyl)trifluoroacetoamide (BSTFA), BSTFA/Py-GC, was developed for analysing the end groups of cinnamyl alcohols and cinnamyl aldehydes in lignin simultaneously, using a dry-iced cooled sample-introduction apparatus for a Curie-point pyrolyzer suitable for the analysis of thermal labile samples. BSTFA/Py-GC of a dehydrogenative polymer (M-DHP, enzymatically prepared from a mixture of coniferyl alcohol and coniferyl aldehyde (1:1 mol/mol)), and a Japanese cedar (Cryptomeria japonica D. Don) wood, were performed at 590 C for 4s. BSTFA/Py-GC of M-DHP provided trimethylsilyl (TMS) ethers of coniferyl alcohol and coniferyl aldehyde as the main products, along with vanillin TMS ether. The cedar wood provided a large level of coniferyl alcohol diTMS ether and a trace level of coniferyl aldehyde TMS ether, suggesting that the cedar native lignin contains a very small abundance of the pyrolytic sources producing coniferyl aldehyde. A comparison of the pyrolytic efficiencies producing coniferyl alcohols and aldehydes among different pyrolysis methods showed the high sensitivity of BSTFA/Py. Unlike BSTFA/Py-GC, capable of analysing both end groups, the pyrolysis of M-DHP in the presence of tetramethylammonium hydroxide provided coniferyl alcohol dimethyl ether and no coniferyl aldehyde methyl ether, suggesting that this method provides useful information on cinnamyl alcohol end groups, but no information on cinnamyl aldehyde end groups.
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pyrolysis trimethylsilylation analysis of lignin preferential formation of cinnamyl alcohol derivatives
Journal of Analytical and Applied Pyrolysis, 2000Co-Authors: Ken-ichi KurodaAbstract:Abstract This paper describes a pyrolysis-trimethylsilylation procedure that is a new pyrolysis-derivatization thermochemolysis procedure of lignin. N , O -Bis(trimethylsilyl)trifluoroacetamide (BSTFA) was used as a trimethylsilylating reagent. A bulk dehydrogenative polymer of coniferyl alcohol (G-DHP) and a Japanese cedar ( Cryptomeria japonica D. Don) wood were pyrolyzed in the presence of BSTFA at 500°C for 4 s. The resultant volatile products were analyzed by gas chromatography/mass spectrometry (GC/MS). The G-DHP and the wood produced large abundances of trimethylsilyl (TMS) derivatized coniferyl alcohol (CA-(TMS) 2 ), in which both the phenolic and alcoholic hydroxyl groups are derivatized with TMS. CA-(TMS) 2 accounted for about 68% of the TMS derivatized products in the G-DHP pyrolysis, and about 24% of those in the wood pyrolysis. The results indicated that pyrolysis in the presence of trimethylsilylating reagents such as BSTFA is a potentially useful technique for drawing information on the pyrolytic precursors of cinnamyl alcohols (such as cinnamyl alcohol-end groups) from lignin. Pyrolysis-trimethylsilylation occurs in a one-step process and provides the TMS derivatives that are immediately available for the subsequent GC(/MS) analysis. This method is applicable to all lignocellulosic materials.
I Molnarperl - One of the best experts on this subject based on the ideXlab platform.
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identification and quantification of ibuprofen naproxen ketoprofen and diclofenac present in waste waters as their trimethylsilyl derivatives by gas chromatography mass spectrometry
Talanta, 2008Co-Authors: A Sebők, A Vasanitszsigrai, Gy Palko, Gy Zaray, I MolnarperlAbstract:This paper reports a derivatization, mass fragmentation study relating to the most common, non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, naproxen, ketoprofen and diclofenac, identified and quantified in the aquatic environment. Derivatizations have been performed with four silylation reagents in order to select the most proper one, taking into account analytical and financial points of view, equally. The tested reagents were N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA), N-methyl- N-(trimethylsilyl)trifluoroacetamide (MSTFA), N-methyl-N-tert-butyldimethylsilyl-trifluoroacetamide (MTBSTFA) and for this purpose at the first time, hexamethyldisilazan (HMDS) + trifluoroacetic acid (TFAA). Varying derivatization time and temperature, taking into consideration chemical and financial advan- tages, HMDS + TFAA proved to be the optimum selection. Responses of derivatives have been compared, as a function of the ionization technique (external/internal ionization), as well as on the treatment of compounds' selective fragment ions (SFIs): (i) extracting the corresponding, characteristic m/z masses from TIC elutions and (ii) from SIM elutions, in parallel. Reproducibilities of measurements, expressed in relative standard deviation percentages (R.S.D.%), including the nanogram and the low picogram levels of injected derivatives, provided an average between 0.93 R.S.D.% and 4.11 R.S.D.%. NSAIDs' enrichment was performed with solid-phase extraction (SPE), applying the Oasis HLB (Waters) cartridges: recoveries in the 1-6 gL −1 range varied between 84% and 111%, with an average reproducibility of 6.4 R.S.D.%. The utility of the optimized derivatization method is presented, on monthly basis, by the identification and quantitation of the ibuprofen, naproxen, ketoprofen and diclofenac content of the influent and effluent waste-water samples obtained from a Hungarian waste-water treatment plant. © 2008 Elsevier B.V. All rights reserved.
Olive Trapp - One of the best experts on this subject based on the ideXlab platform.
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development of an advanced derivatization protocol for the unambiguous identification of monosaccharides in complex mixtures by gas and liquid chromatography
Journal of Chromatography A, 2018Co-Authors: Mare Haas, Saskia Lamou, Olive TrappAbstract:The separation and analysis of complex monosaccharide mixtures is highly challenging and requires typically carefully selected derivatization procedures to avoid changes in the sample composition. Here we present in a comparative study several single- and two-step derivatization approaches for LC and GC separations using a set of reference compounds ranging from C1 building block such as formaldehyde to C6 monosaccharides. Separation conditions have been optimized resulting in the simultaneous separation of 15 unbranched aldoses. By parallel derivatization using hydroxylamine hydrochloride (HACl)/ N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) and O-ethylhydroxylamine hydrochloride (EtOx)/ N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) and comparative GC measurements we developed a protocol for the unambiguous identification and separation of aldoses, ketoses, alditols and aldonic acids, which commonly occur in complex sugar mixtures as reaction by-products or decomposition products. In particular this procedure helps to deconvolute overlapping analytes and facilitates quantification. Additionally, the method presented here has been investigated in regard to storage life, detection limits, quantification and MS analysis. The broad applicability of this method to different sample matrices is shown for the analysis of food samples and complex aldol reaction mixtures in the formose reaction, which is of great relevance in the context of the origin of life.
Yuki Nakayama - One of the best experts on this subject based on the ideXlab platform.
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n o bis trimethylsilyl trifluoroacetamide BSTFA
e-EROS Encyclopedia of Reagents for Organic Synthesis, 2016Co-Authors: Katsuji Ito, Yuki NakayamaAbstract:[25561-30-2] C8H18F3NOSi2 (MW 257.40) InChI = 1S/C8H18F3NOSi2/c1-14(2,3)12-7(8(9,10)11)13-15(4,5)6/h1-6H3/b12-7+ InChIKey = XCOBLONWWXQEBS-KPKJPENVSA-N (reagent for trimethylsilylation, deprotection, dehydrogenation, allylic alkylation, formation of nitronate, and Claisen rearrangement) Physical Data: bp 45–55 °C/14 mmHg; d 0.969 g cm−3. Solubility: soluble in many aprotic organic solvents. Form Supplied in: colorless to very light yellowish liquid; widely available. Purification: distillation under an inert atmosphere. Handling, Storage, and Precautions: moisture sensitive; should be stored in cool and protected from moisture; should be handled with proper skin and eye protection in a well-ventilated fume hood.
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Asymmetric Henry Reactions of Aldehydes Using Chiral Biaryl-Based Bis(thiourea) Organocatalysts
Synlett, 2013Co-Authors: Yuki Nakayama, Yusaku Hidaka, Katsuji ItoAbstract:Biaryl-based bis(thiourea) was found to be an efficient organocatalyst for the asymmetric Henry reaction. High enantioselectivity of up to 93% ee was obtained for the reaction of nitromethane with aryl aldehydes when the combination of N,O-bis(trimethylsilyl)trifluoroacetoamide (BSTFA) with a catalytic amount of potassium acetate was used as the base.
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Encyclopedia of Reagents for Organic Synthesis - N,O‐Bis(trimethylsilyl)trifluoroacetamide (BSTFA)
Encyclopedia of Reagents for Organic Synthesis, 1Co-Authors: Katsuji Ito, Yuki NakayamaAbstract:[25561-30-2] C8H18F3NOSi2 (MW 257.40) InChI = 1S/C8H18F3NOSi2/c1-14(2,3)12-7(8(9,10)11)13-15(4,5)6/h1-6H3/b12-7+ InChIKey = XCOBLONWWXQEBS-KPKJPENVSA-N (reagent for trimethylsilylation, deprotection, dehydrogenation, allylic alkylation, formation of nitronate, and Claisen rearrangement) Physical Data: bp 45–55 °C/14 mmHg; d 0.969 g cm−3. Solubility: soluble in many aprotic organic solvents. Form Supplied in: colorless to very light yellowish liquid; widely available. Purification: distillation under an inert atmosphere. Handling, Storage, and Precautions: moisture sensitive; should be stored in cool and protected from moisture; should be handled with proper skin and eye protection in a well-ventilated fume hood.
A Sebők - One of the best experts on this subject based on the ideXlab platform.
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identification and quantification of ibuprofen naproxen ketoprofen and diclofenac present in waste waters as their trimethylsilyl derivatives by gas chromatography mass spectrometry
Talanta, 2008Co-Authors: A Sebők, A Vasanitszsigrai, Gy Palko, Gy Zaray, I MolnarperlAbstract:This paper reports a derivatization, mass fragmentation study relating to the most common, non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, naproxen, ketoprofen and diclofenac, identified and quantified in the aquatic environment. Derivatizations have been performed with four silylation reagents in order to select the most proper one, taking into account analytical and financial points of view, equally. The tested reagents were N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA), N-methyl- N-(trimethylsilyl)trifluoroacetamide (MSTFA), N-methyl-N-tert-butyldimethylsilyl-trifluoroacetamide (MTBSTFA) and for this purpose at the first time, hexamethyldisilazan (HMDS) + trifluoroacetic acid (TFAA). Varying derivatization time and temperature, taking into consideration chemical and financial advan- tages, HMDS + TFAA proved to be the optimum selection. Responses of derivatives have been compared, as a function of the ionization technique (external/internal ionization), as well as on the treatment of compounds' selective fragment ions (SFIs): (i) extracting the corresponding, characteristic m/z masses from TIC elutions and (ii) from SIM elutions, in parallel. Reproducibilities of measurements, expressed in relative standard deviation percentages (R.S.D.%), including the nanogram and the low picogram levels of injected derivatives, provided an average between 0.93 R.S.D.% and 4.11 R.S.D.%. NSAIDs' enrichment was performed with solid-phase extraction (SPE), applying the Oasis HLB (Waters) cartridges: recoveries in the 1-6 gL −1 range varied between 84% and 111%, with an average reproducibility of 6.4 R.S.D.%. The utility of the optimized derivatization method is presented, on monthly basis, by the identification and quantitation of the ibuprofen, naproxen, ketoprofen and diclofenac content of the influent and effluent waste-water samples obtained from a Hungarian waste-water treatment plant. © 2008 Elsevier B.V. All rights reserved.
