乙腈

The conclusions were as follows: theνO-H andνC=O IR absorption maxima shifted towards higher wave numbers after imprinting 17β-estradiol on TFMAA-co-TRIM copolymer with the red shift of theνO-H groups being apparent after precipitation polymerization for 16h while that forνC=O groups being observed after polymerization for 24h. A strong interaction between TFMAA and 17β-estradiol was confirmed by the high selectivity for 17β-estradiol, as indicted by the values of the separation factor of isomers of 17β-estradiol/17α-estradiol (2.28) and the imprinted factor (3.01). Particle diameter of TFMAA-co-TRIM polymer was between 300 nm and 1.5μm, which suited well for solid phase sorbent throughout at low column pressure. The recognition of imprinting TFMAA-co-TRIM polymer for sterol molecules was driven by enthalpy eluted with acetronitile, and low temperature was in favor of the separation of sterol structure analogues on imprinting column. TFMAA-co-TRIM polymer possessed of determinate anti-heat stability, with melting point beginning at 255.84℃, Tp=257.40℃, control TFMAA-co-TRIM polymer and imprinting TFMAA-co-TRIM polymer were respectively decompounded at 267.79℃and 343.11℃, and solid micro-extraction noddle prepared by the special polymerization also showed definite recognition for 17β-estradiol by GC/MS detecting at 270℃. By selection of various washing and elution solvents, elution reagents of close polymerization system were of more advantage in template molecules retention and recognition on molecularly imprinted solid phase extraction column. At a certain extent, progesterone, 17α-estradiol, 17β-estradiol and 4-androstene-3, 17-dione could be intercepted on the MISPE column. Especially, MISPE had high selectivity for progesterone, and imprinting TFMAA-co-TRIM polymer could achieve adsorption balance within 50 min by absorption kinetics test for 17β-estradiol. However, MISPE column showed better selectivity and enrichment property for 17β-estradiol than C18 and CSPE columns according to the data from HPLC and GC/MS analyses. Recovery of 17β-estradiol on MISPE column was up to 85.5% while when prime extracting solution of milk powder was sampled, the recovery of CSPE and C18 columns were 43.7% and 30.7%, respectively.

通过研究阐明：紫外聚合产物TFMAA-co-TRIM中的νO-H振动吸收峰在聚合16h后红移，νC=O振动吸收峰在聚合24h后红移；TFMAA-co-TRIM对雌二醇异构体的印迹因子达到了3.01，α为2.28，优于其它功能单体参与得到的聚合物识别特性；TFMAA-co-TRIM聚合物粒径介于300 nm至1.5μm之间，作为色谱固定相具有良好的通量和低的柱压；在乙腈流动相中，TFMAA-co-TRIM分子印迹固定相的分离过程主要被焓驱动，低温有利于分子印迹固定相分离甾醇结构类似物；TFMAA-co-TRIM分子印迹聚合物在255.84℃时开始熔融，Tp=257.40℃，聚合物CP的降解温度在267.79℃，MIP降解温度在343.11℃，制备的固相微萃取头初步经GC/MS 270℃的耐热性测定；不同的洗提溶剂筛选证明了选择接近聚合溶剂的洗脱体系更有利于MISPE发挥识别效应；分子印迹固相萃取柱对孕酮、17α-雌二醇、17β-雌二醇和雄烯二酮都具有不同程度的保留特性，可作为此类化合物的吸附材料，特别对孕酮强保留的富集特性，可作为孕酮的选择性识别吸附剂，其分子印迹聚合物对17β-雌二醇的吸附动力学测定显示在50 min内基本达到吸附平衡，具有作为传感器核心敏感材料的潜力；对比萃取奶粉中17β-雌二醇性能，MISPE柱比非分子印迹固相萃取柱和C18柱具有更高的保留，回收率依次为85.5%，43.7%和30.7%。

Was packed electrokinetically and the separation performance of basic compounds was investigated in the pressurized capillary electrochromatography system using 1 μm nonporous bare silica spheres as stationary phase and acetonitrile-water as mobile phase. The effects of the composition of the mobile phase, the concentration of the buffer, pH value, applied voltage and so on on the separation performance were investigated.

以乙腈-水体系作为流动相，详细考察了碱性化合物在该色谱柱上的加压电色谱分离性能，讨论了流动相比例、缓冲液浓度、pH值及操作电压等因素对分离的影响。

A post-column oxidation of the elute solution from HPLC, in the presence of 〓 in HCl, was applied to convert organomercury compounds into Hg for cold vapor generation.

采用ODS柱，以甲醇、乙腈和水（65：15：20，v/v/v）混合溶液（pH 3.5为流动相，表面活性剂富集相中的四种汞-APDC络合物在HPLC中得到基线分离。

The Pictet-Spengler reaction of D-tryptophan methyl ester hydrochloride II-42 with piperonal II-34 in various solvents was extensively studied. The best stereoselectivity (cis/trans=99:1) was obtained using nitromethane or acetonitrile as the solvent.

我们研究了在不同溶剂中，D-色氨酸甲酯盐酸盐II-42和胡椒醛II-34发生的Pictet-Spengler反应的立体选择性，发现当分别用硝基甲烷和乙腈做溶剂时反应的立体选择性达到最高， cis：trans的比例为99： 1。

The effect of various solvents such as water, ethanol and acetonitrile on the title reaction was assessed by the polarizable continuum model.

采用自洽反应场极化连续模型研究了反应体系在水、乙醇和乙腈溶液中反应的溶剂化效应。

The solvent effects were studied with the conductor-like polarizable continuum model respectively in the solvents acetonitrile and water, and we found that the solvent effects reduce the activation energy, but the reduction is small, these reactions are not sensitive to the solvent polarity.

采用导电极化连续介质模型分别研究了在乙腈与水溶液中反应的溶剂化效应，发现这些溶剂可降低反应的活化能，但降低的程度比较小，反应速率变化不大。

The better labeling conditions are as follows:dry acetonitrile as solvent, the mole ratio of K/222 to K 2CO 3 is 1∶1, reaction time is 5 min at 80 ℃. The radiochemical yield is about 57% which is about 3 times higher than the published data.

得出较佳标记条件：以无水乙腈为溶剂，K/ 2 2 2与K2 CO3 摩尔比为1，80℃下反应 5min ，标记率为 5 7%，比文献值提高了 3倍以上。

Results: we got the highest 18F-FDG productivity (55%) and radiochemistry purity (93%) with 0.2ml K2CO3, 0.3ml BMI, 0.7ml acetonitrile and TATM 25mg.

结果：采用25mg TATM在0.2ml K2CO3、0.3ml离子液体体积、0.7ml乙腈时获得最高的合成效率(55%)和放射化学纯度(93%)。

For determination the content of isomaltooligosaccharide in beverage, a high performance liquid chromatography method was established by using 300 mm×4 6 mm, 5 μm Hypersil NH 2 column, acetonitrile+water=78+22 as mobile phase, detector was diffeential refractometer with 40℃ internal temprature.

为测定饮料中异麦芽低聚糖的含量，建立了使用 30 0mm× 4 6mm ，5 μmHypersil NH2 柱，乙腈+水=78+ 2 2为流动相，内部温度为 4 0℃的示差检测器的高效液相色谱法。

Methods The background electrolyte was 50 mmolL^(-1) sodium borate containing 5% acetonitrile. The voltage was 12 kV and the wavelength was set at 228 nm. The fingerprint, produced from electropherograms of ten different batches of samples, was established and 11 common peaks were confirmed.

以的50 mmolL^(-1)硼砂（含体积分数为5%的乙腈溶液）为背景电解质，运行电压12 kv，紫外检测波长228 nm，以10个不同产地药材的电泳图谱建立了甜瓜蒂毛细管电泳指纹图谱。

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。