乙腈

Standard Preparation: Stock standard was prepared in 76:24 acetonitrile: water.

标准的准备工作：库存标准编写76：24乙腈：水。

There is simply not enough acetonitrile available to efficiently run their labs using traditional liquid chromatography technology.

为了使实验室保持效率，使用传统的液相色谱技术都面临着乙腈短缺的问题。

A evaluation method for the performances and quality of chromatographic grade acetonitrile with ultraviolet spectrophotometry and high performance liquid chromatography is presented.

利用紫外分光光度计和高效液相色谱仪建立了色谱纯乙腈的性能和质量的评价方法。

But recent world events have conspired to push the cost of acetonitrile up to levels three-fold their market prices last year.

但是就在去年，由于当今世界形势的迫使，使得乙腈的市场价格翻了三翻。

The proteins and enzymes in saliva sample were removed by centrifugation and filtration of the mixture of acetonitrile and saliva sample.

将等体积的乙腈和唾液混合，然后通过离心和过滤的方法除去唾液样本中的蛋白质和酶。

The mobile phase was a mixture of acetonitrile 0.378 mol/L acetum (30∶70) and in a flow rate of 0.8 mL/min; The detective wavelength was 321 nm; Column temperature was room temperature and the injection quantity was 10 μ L.

色谱柱 Lichrospher C 18 (4.6 mm ×250 mm，5 μm)，C 18 保护柱；流动相：乙腈 0.378 mol/L冰醋酸水溶液(30∶70)；检测波长321 nm；流速0.8 mL/min；柱温：室温；进样量10 μL。

Due to sourcing difficulties and high costs for acrylonitrile, Romer Labs claims "many of our customers are now using this methanol method".

由于乙腈的市场短缺和高昂的价格，Romer Labs扬言："我们的很多客户现在都已经使用甲醇替代方法了。"

The aliquot was determined and confirmed by gas chromatography-negative chemical ionization mass spectrometry using external standard method.

样品中三唑醇残留物由正己烷饱和的乙腈(含1%冰醋酸)提取，加入无水硫酸镁与无水醋酸钠振荡促使提取液分层后进行固相分散萃取净化，用气相色谱-负化学离子源质谱法进行测定与确证，外标法定量。

Melamine is eluted from the SPE cartridge with 5% ammonium hydroxide / methanol, evaporated to dryness, reconstituted with internal standard and 50% acetonitrile / water, and analyzed by LC/MS/MS.

三聚氰胺使用5%的氢氧化铵/甲醇从SPE柱中洗脱，蒸发至干燥，用内标物与50%的乙腈/水重新配置成原来的浓度，通过LC/MS/MS分析。

This article mainly established the analysis method to extract the oxine-copper residues in cucumber and soil with ion pair of antiphase HPLC and Ultrasonic-assisted solvent. This method mainly uses XBridge C18 column and UV detector by using waters phase of phosphatic buffered solution/acetonitrile (60:40, by vol) as mobile phase with 0.8 mL/min flow ratio and UV detection at 250 nm. The residue time was 4.71 minute. Accuracy, precision, and sensitivity of the method all satisfy the demands of pesticide residue analysis.

建立了黄瓜和土壤中喹啉铜的超声波辅助溶剂提取－反相离子对高效液相色谱法的残留分析方法，该方法使用XBridge C18色谱柱和可变波长紫外检测器，并以水相磷酸盐缓冲溶液－乙腈（体积比为60：40）作流动相；流速为0.8 mL/min；检测波长为250 nm；保留时间为4.71 min；该方法的准确度、精密度及灵敏度均满足农药残留分析的要求。

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。