Development of Novel Absolute Determination Methods for Chiral Organic Compounds and Lithium

1. 提出了一种不需要校准曲线和比较标准的手性法测定含磷氨基酸型除草剂草铵膦（D,L-GLUF）绝对含量的新方法。这种方法是基于不同对映体比例的已知数量的对映体与样品的尖峰后对映体比例的变化。在样品中加入已知量的L-GLUF，用丹酰氯衍生化，用γ-环糊精修饰的毛细管区带电泳紫外检测法测定D-异构体与l -异构体的峰面积之比。用合成样品对方法的准确度和精密度进行了评价。D-和L-GLUF的平均值与1.6%以内的平均值一致；重现性低于2.8%。此外，还研究了荧光检测和大体积样品堆积毛细管电泳，以分离和检测飞摩尔水平的痕量D，L-GLUF。提出了一种新的分析方法——亚化学计量同位素稀释核磁共振分析（SID-NMR）。目前的方法包括Li^+与亚化学计量量的密码体[2.1.1]（C211）的络合，以及随后用^7Li- nmr测量^7Li同位素的信号强度。在核磁共振谱中，Li(C211)^+配合物的共振信号（化学位移）与游离Li^+的共振信号（化学位移）完全分离，并对一定量Li(C211)^+配合物的信号积分面积进行了亚化学计量测量。以Li-β-二酮配合物为外标物，在（4.1 ~ 8.2）× 10^<-3> mol dm^<-3> Li范围内，积分面积的重复性为2.1%。通过对合成溶液中锂的测定，证明了SID-NMR的有效性和实用性。

1. A novel absolute determination method using chirality without any calibration curves or comparison standards has been proposed for phosphorus-containing amino acid-type herbicides, glufosinate (D,L-GLUF). This method is based on a change in the enantiomeric ratio after the spiking of a known amount of the enantiomers with different enantiomeric ratios to a sample. D,L-GLUF was determined by adding a known amount of L-GLUF to the sample, derivatizing them with dansyl chloride, and measuring the ratio of the peak area of the D-isomer to that of the L-isomer by means of γ-cyclodextrin modified capillary zone electrophoresis with UV detection. The accuracy and precision of the method were evaluated using a synthetic sample. The mean values obtained for D- and L-GLUF agreed with the values taken within 1.6% ; also the reproducibility was as good as less than 2.8%. Furthermore, fluorescence detection and large-volume sample stacking for the capillary electrophoresis were studied to resolve and detect trace D,L-GLUF in femto-mole levels.2. A novel analytical method, substoichiometric isotope dilution nuclear magnetic resonance analysis (SID-NMR), has been proposed. The present method consists of the complexation of Li^+ with a substoichiometric amount of cryptand [2.1.1] (C211) and the subsequent signal intensity measurement of an isotope of ^7Li by ^7Li-NMR. The resonance signal (chemical shift) of the Li(C211)^+ complex was completely separated from that of free Li^+ in the NMR spectrum and the integrated area of the signal from a constant amount of the Li(C211)^+ complex was substoichiometrically measured. The reproducibility of the integrated area was 2.1% as relative standard deviation for (4.1-8.2) × 10^<-3> mol dm^<-3> Li when a Li-β-diketone complex was used as an external standard. The validity and the usefulness of SID-NMR were demonstrated by the determination of Li in a synthetic solution.