Formation of multiple trimethylsilyl derivatives in the derivatization of 17α-ethinylestradiol with BSTFA or MSTFA followed by gas chromatography-mass spectrometry determination

N,O-bis（trimethylsily）trifluoroacetamide （BSTFA） and N-methyl-N（trimethylsily） trifluoroacetamide （MSTFA） are common derivatization reagents used in the GC-MS analysis of estrogen steroids such as estrone （El） and 17α-ethinylestradiol （EE2）. In this study, three trimethylsilyl （TMS） steroid derivatives, mono- and di-trimethylsilyl EE2 and mono-trimethylsilyl El, were observed during the derivatization of EE2 with BSTFA or MSTFA and/or GC separation. Factors influencing the production of multiple TMS derivatives and their relative abundance were examined. It was found that both methanol and bisphenol A competed with estrogenic esteroids when reacting with silylation reagents, and thus affected the formation of TMS derivatives and their relative abundance in the derivatization products. Methanol was found to be more reactive than bisphenol A with the BSTFA reagent. None of the three solvents tested in this study could prevent the generation of multiple TMS derivatives during the derivatization of EE2 with BSTFA, followed by GC analysis. A similar result was observed using MSTFA as the derivative reagent followed by GC analysis. Thus, the suitability of BSTFA or MSTFA as the derivatization reagent for the determination of E1 and EE2 by GC-MS, under the conditions reported here, is questionable. This problem can be solved by adding trimethylsilylimidaz （TMSI） in the BSTFA reagent as recommended, and the performance of the method has been proved in this study.

Asymmetric Synthesis of (-)-1-Trimethylsilyl-ethanol with Immobilized Saccharomyces Cerevisiae Cells in Water/Organic Solvent Diphasic System

Asymmetric synthesis of (-)-1-trimethylsilyl-ethanol with immobilized Saccharomyces cerevisiae cells in water/organic solvent biphasic system was studied,The effects of shake speed,hydrophobictiy of organic solvent ,volume ratio of water phase to organic phase,pH value of aqueous phase and reaction temperature on the initial reaction rate,maximum yield and enantiomeric excess(ee) of the product were systematically explored,All the above-mentioned factors had significant infuence on the reaction.n-Hexane was found to be the best organic solvent for the reaction.The optimum shake speed,volume ratio of water phase to organic phase,pH value and reaction temperature were 150 r.min^-1,1/2,8 and 30℃ respectively,under which the maximum yield and enantiomeric excess of the product were as high as 96.8% and 95.7%,which are 15% and 16% higher than those of the corresponding reaction performed in aqueous phase ,To our best knowledge,this is the most satisfactory result obtained.

TRIMETHYLSILYLATED SILICA AS RHEOLOGY MODIFIER FOR SILICONE RESINS

Trimethylsilylated silica was synthesized. through hydrolytic condensation of tetraethoxysilane followed by trimethylsilylation. Rheological properties of the silicone resin with trimethylsilylated silica as modifier were studied. It turned out that the particle size of silica was important to the rheological behavior of the modified resin. Trimethylsilylated silica of medium particle size shows the strongest tendency of forming physical network in the resin.

Adjusting the solvation structure with tris(trimethylsilyl)borate additive to improve the performance of LNCM half cells

Tris(trimethylsilyl)borate(TMSB) has been intensively studied to improve the performances of lithiumion batteries. However, it is still an interesting issue needed to be resolved for the research on the Li^(+) solvation structure affected by TMSB additive. Herein, the electrochemical tests, quantum chemistry calculations, potential-resolved in-situ electrochemical impedance spectroscopy measurements and surface analyses were used to explore the effects of Li^(+) solvation structure with TMSB additive on the formation of the cathode electrolyte interface(CEI) film in LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)/Li half cells. The results reveal that the TMSB additive is easy to complex with Li^(+) ion, thus weaken the intermolecular force between Li^(+) ions and ethylene carbonate solvent, which is benefit for the cycle performance. Besides, the changed Li^(+) solvation structure results in a thin and dense CEI film containing compounds with Si–O and B–O bonds which is favorable to the transfer of Li^(+) ions. As a result, the performances of the LNCM811/Li half cells are effectively improved. This research provides a new idea to construct a high-performance CEI film by adjusting the Li^(+) solvation structures.

Efficient oxidative deprotection of trimethylsilyl,tetrahydropyranyl and methoxymethyl ethers under solvent-free conditions

A mild, efficient and fast method for direct oxidation of trimethylsilyl, tetrahydropyranyl and methoxymethyl ethers to their corresponding carbonyl compounds using trinitratocerium（Ⅳ） bromate （TNCB） supported on NaHSO4.H2O under solvent-free conditions is reported.

XPS STUDIES ON SURFACE MODIFIED POLY [1-(TRIMETHYLSILYL)-1-PROPYNE] MEMBRANES Ⅱ SURFACE MODIFICATION BY BROMINE VAPOR

Surface modification of poly [1-(trimethylsilyl)-1-propyne] (PTMSP) membranes bybromine vapor has been studied. It is shown that Br/C atomic ratio at the surfaces increased withthe time of bromination until about 60 min, then it reached a plateau. The results of XPS and IRstudies indicated that the addition of bromine to double bonds and the replacement of H on CH_3 bybromine had taken place so that a new peak at 286.0 eV (C--Br)in C_(1s) spectra and some newbands, e. g. at 1220 and 580cm^(-1) in IR spectra were formed. The fact,t Po_2, permeability ofoxygen, decreased and α_(O_2/N_2), separation factor of oxygen relative to nitrogen, increased withbromination time, shows that surface modification of PTMSP by bromine may be an efficient approach to prepare PTMSP membranes used for practical gas separations.

Tris(trimethylsilyl) borate as an electrolyte additive for high-voltage lithium-ion batteries using LiNi_(1/3)Mn_(1/3)Co_(1/3)O_2 cathode

The influence of tris(trimethylsilyl) borate (TMSB) as an electrolyte additive on lithium ion cells have been studied using Li/LiCo1/3Ni1/3Mn1/3O2 cells at a higher voltage, 4.7 V versus Li/Li+. 1 wt% TMSB can dramatically reduce the capacity fading that occurs during cycling at room temperature (RT) and elevated temperature (60 degrees C). After 150 cycles at 1 C rate (1 C= 278 mAh/g), the capacity retention of Li/LiCo1/3Ni1/3Mn1/3O2 is up to near 72% in the electrolyte with TMSB added, while it is only about 35% in the baseline electrolyte. The electrochemical behaviors, the surface chemistry and structure of Li/LiCo1/3Ni1/3Mn1/3O2 cathode are characterized with charge/discharge test, linear sweep voltammetry (LSV), X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS), thermal gravimetric analyses (TGA), scanning electron microscope (SEM) and transmission electron microscopy (TEM). These analysis results reveal that the addition of TMSB is able to protectively modify the electrode CEI film in a manner that suppresses electrolyte decomposition and degradation of electrode surface structure, even though at both a higher voltage of 4.7 V and an elevated temperature of 60 degrees C. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.

Enhanced efficiency and stability in Sn-based perovskite solar cells by trimethylsilyl halide surface passivation

Lead free tin perovskite solar cells(PKSCs)are the most suitable alternative candidate for conventional lead perovskite solar cells.However,the efficiency and the stability are insufficient,mainly because of the poor film quality and numerous defects.Here we introduce an efficient strategy based on a simple trimethylsilyl halide surface passivation to increase the film quality and reduce the defect density.At the same time,a hydrophobic protective layer on the perovskite surface is formed,which enhanced the PKSCs’stability.The efficiency of the solar cell after the passivation was enhanced from 10.05%to 12.22%with the improved open-circuit voltage from 0.57 V to 0.70 V.In addition,after 92 days of storage in N_(2) filled glovebox,the modified T-PKSCs demonstrated high stability maintaining 80%of its initial efficiency.This work provides a simple and widely used strategy to optimize the surface/interface optoelectronic properties of perovskites for giving more efficient and stable solar cells and other optoelectronic devices.

GC-MS STUDY ON DIURETICS IN URINE Ⅱ.DETECTION METHOD USING TRIMETHYLSILYLATION

A reliable method is described for the detection of amitoride,triamterene. canrenone and spironolactone in human urine using GC-MS analysis after trimethytsitytation.The mass spectrometric and metabotic features of the compounds are discussed

3-(三甲基硅基)丙炔酰氯的合成研究

3-(三甲基硅基)丙炔酰氯是合成防治小麦全蚀病杀菌剂硅噻菌胺的重要中间体,以丙炔醇■为起始原料,经硅烷化后与格氏试剂发生三甲基硅基交换得3-(三甲基硅基)丙炔醇■经2,2,6,6-四甲基哌啶氧化物(TEMPO)催化氧化得3-(三甲基硅基)丙炔醛■经氯代得3-(三甲基硅基)丙炔酰氯■,纯度98%(GC),总收率78%。产物经~1H NMR、^(13)C NMR和MS结构表征确证。该合成方法反应条件温和、收率较高、经济性好、便于生产,具有工业化前景。

六甲基二硅胺烷在有机合成领域的研究进展

六甲基二硅胺烷在光刻涂胶工艺、薄膜制备、电化学、有机合成等领域应用广泛,综述了其在有机合成领域的研究进展,并展望了其发展趋势。

芳香族液晶聚酯的组成分析

芳香族液晶聚酯(LCP)难溶于常用溶剂,给其组成分析带来了巨大的挑战。针对这一问题,提出了基于胺解和水解效应的间接分析方法,对LCP的氢氧化钠水溶液(NaOH/H_(2)O)水解产物和乙醇胺(META)胺解产物进行了核磁共振氢谱(^(1)H NMR)表征,对N,O-双(三甲基硅基)-乙酰胺(BSTFA)修饰的氢氧化钠/甲醇/二甲基亚砜(NaOH/CH_3OH/DMSO)水解产物进行了^(1)H NMR和气相色谱-质谱(GC-MS)表征。通过对比发现,以NaOH/CH_(3)OH/DMSO为溶剂水解LCP是可将LCP充分单体化的优选溶剂,而采用GC-MS对单体化后的产物进行表征是获得精确单体物质的量比的优选方法,结合两者为LCP组分分析提供了一种高效、准确的方法。此外,表征方式均表明LCP在聚合过程中发生了不期望但无法避免的副反应和反应物升华,进而导致了单体的损失。

基于BSTFA衍生化法白酒不挥发有机酸研究

白酒中不挥发性有机酸可能是白酒呈酸味的重要化合物,为明晰白酒原酒中不挥发性有机酸的组成与含量,采用N,O-双(三甲基硅烷基)三氟乙酰胺(N,O-bis(trimethylsilyl)trifluoroacetamide,BSTFA)衍生化结合气相色谱-质谱(GC-MS)研究白酒中不挥发有机酸,共检测到27种有机酸。通过定量这些有机酸在7种香型白酒原酒中的分布,发现羟基酸的种类最多,且总浓度最高。在检测的所有有机酸中乳酸含量最高,在几百mg/L至几个g/L之间,远远高于其他不挥发有机酸。大多数不挥发有机酸在酱香型、芝麻香型白酒中的含量较高,在清香和凤香白酒中的含量较低。

南海海洋红树林种子内生真菌2508号多糖G-22a的研究

从南海海洋红树林种子内生真菌 2 5 0 8号的菌体中提取到多糖G_2 2a ,通过酸水解及GC/MS研究表明 ,G_2 2a由鼠李糖、甘露糖和葡萄糖及少量的木糖、核糖醇组成。

煤及其干馏物氧化产品中苯羧酸的GC分析

煤及其干馏物氧化产品中苯羧酸的ＧＣ分析李福祥吕志平薛建伟秦梦庚（太原理工大学精细化工研究所太原０３００２４）关键词煤氧化，苯羧酸，重氮甲烷，酯化煤及其衍生物经碱氧气或高锰酸钾等氧化后的主要产品是水溶性的羧酸混合物，它是一种吸湿性的固体，具有黄色到近...

气相色谱法测定番茄中乙烯利的残留量

建立了一种气相色谱法（GC）测定番茄中乙烯利残留的方法。番茄样品经甲醇-盐酸溶液（V/V=95∶5）提取,无水乙醚萃取,重氮甲烷衍生化,采用GC-NPD检测。结果表明：该方法的平均回收率为92.85%~97.59%,相对标准偏差（RSD）为2.79%~4.38%（n=5）,乙烯利的最小检出浓度为0.015 86mg/kg。该方法的杂质干扰少,准确性和灵敏度高,能快速测定出番茄中乙烯利的残留量。

重氮甲烷衍生-气相色谱法测定黄瓜中乙烯利残留量

黄瓜样品经盐酸-乙醇（5＋95）溶液提取，并离心后经活性炭小柱过滤净化，所得净化液中乙烯利与重氮甲烷进行衍生反应，产物用HP-1701毛细管柱（0．32mm×30m，0．25μm）分离，用火焰光度检测器测定乙烯利。重氮甲烷化乙烯利的质量浓度在0．100-2．50mg·L-1之间与峰面积呈线性。方法用于黄瓜样品中乙烯利的测定，平均回收率为97．3％，相对标准偏差（n=5）为4．5％。

气质联用测定DON和NIV及其衍生方法的比较研究

建立了气相色谱-质谱联用检测单端孢霉烯族B类中的脱氧雪腐镰刀菌烯醇（DON）和雪腐镰刀菌烯醇（NIV）的方法。该方法采用七氟丁酰咪唑（HFBI），三甲基硅烷咪唑（TMSI）-双三甲基硅基乙酰胺（BSA）-三甲基氯硅烷（TMCS）（3：3：2，V／V／V）（TBT）两种衍生试剂分别与毒素进行衍生反应后用GC-MS检测。方法的线性范围为4～1300mg／mL，RSD≤1．52％。此外，对两种衍生方式进行了比较，指出氟化衍生后检测灵敏度高，而硅烷化衍生不需加热，在室温下即可完成，且生成物稳定。分析应用应根据不同检测要求选择相应的衍生试剂。