乙腈

A GC headspace injection method for the determination of residual organic solvents such as methanol, ethanol, acetonitrile, dichloromethane, ethylacetate, 4 methyl 2 pentanone, toluene, DMF, chloroform and tetrahydrofuran in tazobactam was established.

建立了气相色谱顶空进样法测定三唑巴坦中甲醇、乙醇、乙腈、二氯甲烷、乙酸乙酯、甲基异丁基酮、甲苯、N ，N′-二甲基甲酰胺、氯仿和四氢呋喃等有机溶剂的残留量。

Some useful fluorine-containing intermedi-ates were synthesized by the reaction of activated methylenecompounds or silyl enol ether with 2,2-dihydropolyfluoro-alkanoates or 2-hydropolyfluoroalk-2-enoates in the presenceof different bases.

进一步研究表明，在氢化钠的作用下，苯乙腈，苄基苯基甲酮也可以与2-氢多氟-2-烯酸乙酯发生亲核加成反应，苄基苯基甲酮的加成中间体经多聚磷酸环化，得到了间位氟烷基取代的α-萘酚衍生物。

PK values of 3-ethoxy-N-desmethyldiazepam (3-EtO-NDZ) in ethanol and acetonitrile containing various concentrations of sulfuric acid, determined by spectrophotometry and spectropolarimetry, were found to be 3.4 and 0.63 respectively. Temperature dependent racemization of enantiomeric 3-EtO-NDZ in ethanol containing various acid concentrations was studied by monitoring changes of ellipticity at 365 nm as a function of time on a spectropolarimeter.

3-乙氧基－N去甲基安定（3-EtO-NDZ；diazepam=安定）在含不同硫酸浓度的乙醇和乙腈中的pK值用光谱法和旋光光谱法作了测定，其结果分别为3.4和0.63.3-EtO-NDZ之对映异构体在含各种不同酸浓度的乙醇中与温度相关的消旋过程，用旋光光谱仪选择其圆二色谱在365nm波长处强度的改变为时间函数的方法作了测定。

Water samples were extracted and purified and collected by solid-phase extraction LC-18 column. Soil samples were extracted by ethyl acetate/petroleum ether (2:1, by vol) and purified by sulphonation. Wheat sample was extracted by acetonitrile/water (4:1, by vol) and purified and collected by SPE- Florisil column.

水样直接用LC-18固相萃取小柱分离、净化和富集；采用乙酸乙酯／石油醚（体积比2：1）振荡提取，磺化法净化，测定土壤中氯氟吡氧乙酸残留量；以乙腈／水（体积比4：1）为提取剂，氟罗里硅土固相萃取小柱分离、净化，测定小麦样品中氯氟吡氧乙酸的残留量。

The thermal property studies indicate that the mass loss of compound B was 54.39% at 242.2~750℃, and when the temperature was 1000℃, there was 25.11% char residue left, which showed that the title compound has a good thermal stability and char forming capability. Using acetonitrile as the solvent instead of trichloromethane or 1, 2-dichloethane gave higher yield. During the synthesis, the yield was very low when triethylamine was used as acid acceptor alone, and when a little amount of 4-dimethylaminopyridine was added at the same time, the yield could be 81%.

结果表明，所合成的化合物B的结构与预期的结构一致；热性能研究表明，化合物B在242.2~750℃质量损失为54.39%，1000℃时仍有25.11%的炭残渣，显示出优异的热稳定性和成炭性；在相同反应条件下，用乙腈作为溶剂的反应产率比使用氯仿和二氯乙烷为溶剂的高，并且在合成过程中，单独使用三乙胺作为缚酸剂时产率很低，而当同时加入少量4-二甲氨基吡啶时，产率可达81%。

The combined extract was concentrated to dryness and redissolved in acetonitrile, then cleaned up by dispersive solid-phase extraction with sorbents of N-propyl ethylene diamine, graphited carbon black, and C18, and determined and confirmed by GC-NCI/MS.

样品经乙腈提取并浓缩后加入N-丙基乙二胺、石墨化碳黑和C183种填料进行分散固相萃取净化，气相色谱-负化学离子源质谱分时段选择离子监测技术测定与确证，外标法定量。

Samples were saponified with 20 g/L sodium hydroxide. The sexual hormones were then extracted with dichloromethane-acetic acetate (40∶1, v/v) under acidic conditions (pH 3, adjusted with 1 mol/L HCl ). An XTerraTMRP18 column was employed and a mixture of water-methanol-acetonitrile (50∶32∶18, v/v) was used as mobile phase. The seven sexual hormones were detected at 230 nm. The average spiked recoveries for the seven sexual hormones ranged from 75.6% to 97.8% with relative standard deviations of 1.9% to 7.2%. The linear ranges of determination were from 5 to 50 mg/L with correlation coefficients of 0.9999, and the limits of detection were from 3.7 to 12 ng.

先在试样中加入20 g/L氢氧化钠溶液与油脂进行皂化反应，然后用二氯甲烷-乙酸乙酯(体积比为40∶1)混合液在酸性条件下(pH 3)萃取，选择XTerraTMRP18色谱柱，以水-甲醇-乙腈(体积比为50∶32∶18)混合液为流动相，在波长230 nm处检测。7种性激素分离良好并排除了样品中杂质峰的干扰，低、高浓度平均回收率范围为75.6%~97.8%；相对标准偏差为1.9%~7.2%；检出限为3.7~12 ng。

Department of Chemical Pharmacology, Capital University of Medical Science, Beijing 100054, ChinaAbstract: A reversedphase high performance liquid chromatographic method was developed for the simultaneous quantitative determination of caffeine, dapsone and chlorzoxazone. The operation was carried out on a C18 column (250 mmX4.6 mm i.d., 5.0 μm) with the mobile phase of acetonitrilephosphate buffer including 0.02 mol/L KH2PO4 and 0.02 mol/L (C2H53N, pH 6.5(25:75 in volume ratio).

用反相高效液相色谱同时测定血清中咖啡因、氨苯砜、氯唑沙宗探针药物的质量浓度，以乙腈磷酸盐缓冲体系(含 0.02 mol/L的磷酸二氢钾和0.02 mol/L的三乙胺，pH 6.5)(体积比为25：75)为流动相，以安替比林为内标，经C18柱(250 mmX4.6 mm i.d。， 5.0 μm)分离，紫外检测器检测，使3种探针药物得到较好的分离，并且在有效血药浓度范围内线性良好。

A multi-metal alloy catalyst for hydrogenation of acetonitrile to ethylamine was prepared using hydrazine hydrate and potassium borohydride as the co-reductant.

以水合肼和硼氢化钾为共还原剂制备了多元合金催化剂，将其用于乙腈催化加氢反应制乙胺。

Column: Agilent C18; mobile phase 10mol.l-1 monobasic Acetate buffer, 20 molL-1triethylamine solution adjusted to pH5.5 with Acetic acid -acetonitrile ,gradient elution, flow rate: 0.6 mLmin-1; Results:The Traditional Chinese Medicines contained Acarbose, Phenformin and Glibenclamide, and can be separated completely.

色谱柱：Agilent ZORBAX ODS C18柱(5μm，4.6×250mm， Agilent)；流动相：醋酸盐缓冲液(10molL-1醋酸胺，20 molL-1三乙胺，用醋酸调节pH5.5)与乙腈，梯度洗脱，流速：0.6 mLmin-1，色谱检测波长234nm，格列吡嗪为内标物进行定量分析。

Now, however, all children continue in "comprehensive" schools, and the eleven-plus determines which courses of study the child will follow.

然而现在，所有的孩子都要在综合学校继续学习，所以这次考试只是决定他们将要学习哪些课程。

Cultivatable land , and led to a general recognition that development must not be carried at the cost of agriculture .

城区的迅速扩大在很多情况下侵占了宝贵的可耕地，使人们普遍认识到发展不能以牺牲农业为代价。