高效液相色谱/间接紫外检测法分离测定脂肪胺

建立了无紫外光吸收的脂肪胺的高效液相色谱/间接紫外检测分析方法。采用反相C18色谱柱,以对氨基苯酚盐酸盐-有机溶剂为流动相分离测定脂肪胺。研究了背景紫外吸收试剂、有机溶剂、对氨基苯酚盐酸盐对分离和测定的影响,并探讨了保留规律。结果表明,以0.5 mmol/L对氨基苯酚盐酸盐水溶液(pH 4.0)-甲醇(80∶20)作为流动相,在柱温30 ℃、流速1.0 mL/min时,甲胺、乙胺和丙胺3种化合物在14 min内完全分离,检出限分别为0.38、0.59、0.81 mg/L。将方法应用于环境水样的测定,加标回收率为 97.8%~99.1%,相对标准偏差均不大于1.8%。     

高效液相色谱/间接紫外检测法分离测定脂肪胺

建立了无紫外光吸收的脂肪胺的高效液相色谱/间接紫外检测分析方法。采用反相C18色谱柱,以对氨基苯酚盐酸盐-有机溶剂为流动相分离测定脂肪胺。研究了背景紫外吸收试剂、有机溶剂、对氨基苯酚盐酸盐对分离和测定的影响,并探讨了保留规律。结果表明,以0.5 mmol/L对氨基苯酚盐酸盐水溶液(pH4.0)-甲醇(80∶20)作为流动相,在柱温30℃、流速1.0 mL/min时,甲胺、乙胺和丙胺3种化合物在14min内完全分离,检出限分别为0.38、0.59、0.81 mg/L。将方法应用于环境水样的测定,加标回收率为97.8%~99.1%,相对标准偏差均不大于1.8%。     

离子液体作高效液相色谱流动相添加剂分离测定芳香族羧酸

以离子液体作反相高效液相色谱流动相添加剂,建立了分离测定对氨基苯甲酸、邻苯二甲酸、对羟基苯甲酸、水杨酸、苯甲酸、邻甲苯甲酸6种芳香族羧酸的方法。以C18反相色谱柱为分离柱,采用紫外检测方法,以离子液体作高效液相色谱流动相添加剂,考察了检测波长、甲醇含量、离子液体溶液的pH值、离子液体烷基链长度以及离子液体溶液浓度等分离及测定条件。优化得到的色谱条件为:以甲醇和1.0mmol/L 1-丁基-3-甲基咪唑四氟硼酸盐水溶液(pH 3.0)(体积比40∶60)为流动相;检测波长240 nm;流速1.0 mL/min;柱温30℃。在优化条件下对6种芳香族羧酸进行梯度洗脱,约在16.5 min内分离完全;在5~120 mg/L范围内,线性系数均在0.999以上;检出限为0.026~0.082 mg/L。方法的平均加标回收率为98.3%~103.8%,相对标准偏差不高于0.63%。将该方法应用于药品复方紫荆皮水杨酸溶液和足君清酊剂中芳香族羧酸的测定,结果满意。     

Microwave-mediated magneto-optical trap for polar molecules

Realizing a molecular magneto-optical trap has been a dream for cold molecular physicists for a long time. However,due to the complex energy levels and the small effective Lande g-factor of the excited states, the traditional magneto-optical trap(MOT) scheme does not work very well for polar molecules. One way to overcome this problem is the switching MOT,which requires very fast switching of both the magnetic field and the laser polarizations. Switching laser polarizations is relatively easy, but fast switching of the magnetic field is experimentally challenging. Here we propose an alternative approach, the microwave-mediated MOT, which requires a slight change of the current experimental setup to solve the problem. We calculate the MOT force and compare it with the traditional MOT and the switching MOT scheme. The results show that we can operate a good MOT with this simple setup.