(S)-1,1-Diphenylprolinol Trimethylsilyl Ether

2016 ◽  
pp. 309-319
Author(s):  
Robert K. Boeckman Jr. ◽  
Douglas J. Tusch ◽  
Kyle F. Biegasiewicz
Keyword(s):  
Trimethylsilyl Ether

A Rapid Method for Oxidative Deprotection of Trimethylsilyl Ether with Wet Alumina Supported Dess—Martin Periodinane in Solventless System under Microwave Irradiation.

ChemInform ◽  
2004 ◽  
Vol 35 (8) ◽  
Author(s):  
S. Hossein Abdi Oskooie ◽  
Majid M. Heravi ◽  
Noohshin Sarmad ◽  
Akbar Saednia ◽  
Mitra Ghassemzadeh
Keyword(s):  
Microwave Irradiation ◽  
Rapid Method ◽  
Trimethylsilyl Ether

Immunoadsorption to improve gas chromatography/high-resolution mass spectrometry of estradiol-17 beta in plasma.

1983 ◽  
Vol 29 (4) ◽  
pp. 677-680 ◽  
Author(s):  
S J Gaskell ◽  
B G Brownsey
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
High Resolution ◽  
High Resolution Mass Spectrometry ◽  
Trimethylsilyl Ether ◽  
Internal Standard ◽  
Selected Ion Monitoring ◽  
High Resolution Mass ◽  
Precise Quantification ◽  
Resolution Mass

Abstract We describe a new, highly selective procedure for the determination of estradiol-17 beta in plasma. Samples are extracted with a micro-cellulose-coupled antiserum to estradiol-17 beta. Conversion of the extracted steroid to the bis(trimethylsilyl) ether is followed by gas chromatography/high-resolution mass spectrometry with selected ion monitoring. Precise quantification is achieved through the use of [2H3]estradiol-17 beta as internal standard.

Gas-Liquid Chromatography of Trichlorfon in Soluble Powder Formulations

1974 ◽  
Vol 57 (5) ◽  
pp. 1128-1131
Author(s):  
Phil B Bowman ◽  
Peter W Dame
Keyword(s):  
Liquid Chromatography ◽  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Trimethylsilyl Ether ◽  
Gas Liquid Chromatography ◽  
Mass Spectral ◽  
Powder Formulation ◽  
Relative Standard ◽  
Quantitative Recovery

Abstract A procedure is described for the determination of trichlorfon in a soluble powder formulation by gas-liquid chromatography. Silylation prevents on-column degradation of trichlorfon to dichlorvos. The procedure provides quantitative recovery from the formulation as demonstrated by a spiking study. A relative standard deviation of less than 2% was obtained for 6 replicate assays of a single lot of formulation. The mass spectral fragmentations of trichlorfon and trichlorfon-trimethylsilyl ether are described.

Analysis of Organic Acids in Fruit Products by Anion Exchange Isolation and Gas Chromatographic Determination

1973 ◽  
Vol 56 (5) ◽  
pp. 1257-1263 ◽  
Author(s):  
David W Baker
Keyword(s):  
Organic Acids ◽  
Formic Acid ◽  
Anion Exchange ◽  
Exchange Resin ◽  
Trimethylsilyl Ether ◽  
Cation Exchange Resin ◽  
Chromatographic Determination ◽  
Alcoholic Extract ◽  
Resin Column ◽  
Acidic Components

Abstract The method described involves passing an alcoholic extract of fruit product through a cation exchange resin column and then through an anion exchange resin column. Neutral fruit components are washed from the columns with alcohol and acetone solutions. Acidic components trapped on the anion column are eluted using 6N formic acid in acetone. An aliquot of the eluate is evaporated to dryness after the addition of benzene to remove the excess formic acid as an azeotrope. The residue is allowed to react with bis(trimethylsilyl)acetamide or bis(trimethylsilyl)trifluoroacetamide to form trimethylsilyl ether-ester derivatives which are detected by gas chromatography on a nonpolar (OV-1) column. Good recoveries were obtained for some common organic acids (succinic, fumarie, malic, tartaric, trans- aconitic, and citric acids) from fruit juice.

Gas-Liquid Chromatographic/Mass Spectrometric Screening Method for T-2 Toxin in Milk

1979 ◽  
Vol 62 (6) ◽  
pp. 1274-1280
Author(s):  
George J Collins ◽  
Joseph D Rosen
Keyword(s):  
Mass Spectrometry ◽  
Electron Impact ◽  
Chemical Ionization ◽  
Impact Ionization ◽  
Trimethylsilyl Ether ◽  
Screening Method ◽  
Internal Standard ◽  
Electron Impact Ionization ◽  
Gas Liquid Chromatography ◽  
Ionization Mass

Abstract A method for the analysis of T-2 toxin in milk is presented. Ethyl acetate extracts of milk samples which had been spiked with T-2 toxin were purified by thin layer chromatography and derivatized with N,O-bis(trimethylsilyl)acetamide to produce the T-2 toxin trimethylsilyl ether (T-2 toxin-TMS). N,O-bis(trimethylsilyl-d9)acetamide was used to make T-2 toxin d9-trimethylsilyl ether (T-2 toxin-d9TMS) which was added to the derivatized milk extract as an internal standard. Samples were analyzed by combined gas-liquid chromatography/mass spectrometry using either electron impact ionization or chemical ionization mass spectrometry. In electron impact ionization analyses, simultaneous monitoring of the T-2 toxin-TMS fragment ion at m/z 436 and the T-2 toxin-d9TMS fragment ion at m/z 445 gave a T-2 toxin-TMS detectability estimated at 6 μg/kg. In chemical ionization analyses, the T-2 toxin-TMS fragment ion at m/z 377 and the T-2 toxin-d9TMS fragment ion at m/z 386 were simultaneously monitored to give a T-2 toxin-TMS detectability estimated at 3 μg/kg. Average recovery was 85% at 200 μg/kg and 65% at 20 μg/kg.

scholarly journals (S)-α,α-Diphenylprolinol Trimethylsilyl Ether

Synlett ◽  
2012 ◽  
Vol 23 (06) ◽  
pp. 953-954 ◽  
Author(s):  
Aneta Wróblewska
Keyword(s):  
Trimethylsilyl Ether

scholarly journals Leaf Cuticle Can Contribute to Non-Host Resistance to Poplar Leaf Rust

Forests ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 870 ◽  
Author(s):  
Yu ◽  
Shen ◽  
Newcombe ◽  
Fan ◽  
Chen
Keyword(s):  
Host Resistance ◽  
Populus Deltoides ◽  
Rust Fungus ◽  
Trimethylsilyl Ether ◽  
Populus Tomentosa ◽  
Rust Fungi ◽  
Mesophyll Cells ◽  
Defense Compounds ◽  
Leaf Cuticle ◽  
Poplar Leaf

The plant leaf cuticle is a chemically complex but largely waxy outer shell that limits water loss and also prevents some pathogens from gaining access to internal mesophyll. Rust fungi are obligate parasites, and most bypass the cuticle by thigmotropically locating stomata, growing through the stomatal openings, and then parasitizing mesophyll cells with haustoria. It is thought that even non-hosts of a given rust fungus do not resist until their mesophyll cells are contacted in this way. In other words, it is thought that the cuticle plays no role in non-host resistance. Here, we tested the hypothesis that poplar leaf cuticles might contribute to non-host resistance to rust fungi by chemically impeding the germination and growth of urediniosporelings of Melampsora larici-populina. Following an initial survey in China of the resistance of 36 genotypes of various species and interspecific hybrids of Populus to M. larici-populina, we selected three genotypes for the initial test of hypothesis: (1) A Populus purdomii genotype that is fully susceptible; (2) a Populus deltoides cv. ‘I-69′ that is incompletely resistant (i.e., a resistant host); and (3) a Populus tomentosa genotype that is a non-host to M. larici-populina. Urediniospores were assayed for germination in extracts of the cuticles of the three genotypes. Germination was most reduced by the P. tomentosa non-host cuticular extracts that also reduced the growth of germ tubes to 36 times less than that in controls or in the extract of the susceptible P. purdomii. Four cuticular components were identified as putative defense compounds given greater concentrations in P. tomentosa than in P. purdomii: Aucubin, hexakis(trimethylsilyl) ether, catechol, 7,9-Di-tert-buty l-1-oxaspiro (4,5) deca-6, 9-diene-2,8-dione and trifluoroacetamide. These four compounds were then tested, and they reduced urediniospore germination and uredinial density in inoculations of normally susceptible P. purdomii with Melampsora larici-populina. Thus, the cuticle of P. tomentosa can contribute to pre-haustorial, non-host resistance to M. larici-populina.

Liquid Chromatographic Determination of Monensin in Chicken Tissues with Fluorometric Detection and Confirmation by Gas Chromatography-Mass Spectrometry

1986 ◽  
Vol 69 (3) ◽  
pp. 443-448
Author(s):  
Keigo Takatsuki ◽  
Shigeru Suzuki ◽  
Isamu Ushizawa
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Trimethylsilyl Ether ◽  
Phosphate Buffer Solution ◽  
Fluorescent Labeling ◽  
Gas Chromatography Mass Spectrometry ◽  
Fluorometric Detection ◽  
Chicken Tissues ◽  
Chromatography Mass Spectrometry

Abstract An accurate, sensitive method is described for the determination of monensin residue in chicken tissues by liquid chromatography (LC), in which monensin is derivatized with a fluorescent labeling reagent, 9-anthryldiazomethane (ADAM), to enable fluorometric detection. Samples are extracted with methanol-water (8 + 2), the extract is partitioned between CHCl3 and water, and the CHC13 layer is cleaned up by silica gel column chromatography. Free monensin, obtained by treatment with phosphate buffer solution (pH 3) at 0°C, is derivatized with ADAM and passed through a disposable silica cartridge. Monensin-ADAM is identified and quantitated by normal phase LC using fluorometric detection. The detection limit is 1 ppb in chicken tissues. Recoveries were 77.6 ± 1.8% at 1 ppm, 56.7 ± 7.1% at 100 ppb, and 46.5 ± 3.7% at 10 ppb fortification levels in chicken. Gas chromatography-mass spectrometry is capable of confirming monensin methyl ester tris trimethylsilyl ether in samples containing residues >5 ppm.

Estradiol-17 beta determined in plasma by gas chromatography-mass spectrometry with selected ion monitoring of mixed silyl ether-perfluoroacyl ester derivatives and use of various stable-isotope-labeled internal standards.

1989 ◽  
Vol 35 (4) ◽  
pp. 532-536 ◽  
Author(s):  
L Dehennin
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Stable Isotope ◽  
Trimethylsilyl Ether ◽  
Gas Chromatography Mass Spectrometry ◽  
Specific Method ◽  
Silyl Ether ◽  
Selected Ion Monitoring ◽  
Chromatography Mass Spectrometry ◽  
Target Values

Abstract A highly specific method is described for measuring estradiol-17 beta (E2) in plasma by gas chromatography-mass spectrometry (GC-MS) associated with stable isotope dilution. A mixed derivative, E2-3-trimethylsilyl ether-17-heptafluorobutyrate (E2-3-TMS-17-HFB), was found to have excellent analytical properties. The specificity of the derivatization procedure exploits a unique feature of estrogens: the selective exchange of a phenolic perfluoroacyl ester for a trialkylsilyl ether. No significant differences in E2 concentration could be ascribed to the use of 2H- or 13C-labeled analogs, thus ruling out interferences from possible isotope exchange commonly attributed to deuterated compounds. Precision is closely similar to that for methods in which the more common E2-3, 17-bis(trimethylsilyl) ether and E2-3, 17-bis(heptafluorobutyrate) derivatives are used. Sensitivity and specificity of the mixed 3-TMS-17-HFB derivative allow adequate determinations of E2, even in plasma from males, in 2-mL samples. Interlaboratory mean concentrations of E2 obtained by routine immunoassays were consistently higher than the target values estimated by GC-MS, particularly at concentrations less than 100 pmol/L.

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