稀土元素原子发射光谱及其谱线干扰的高分辨率ICP-AES研究Ⅱ.钐基体对其他稀土元素的光谱干扰

稀土元素在当今生产、生活中具有极重要的地位，由于稀土元素的原子发射光谱极为复杂，因此光谱干扰给稀土元素的原子发射光谱分析带来极大的困难。本工作利用高分辨率ＩＣＰ－ＡＥＳ仪器详细研究了Ｓｍ基体对其他稀土元素重要分析线的光谱干扰，获得了大量的光谱及光谱干扰信息，为以稀土为基体的痕量稀土分析线的选择及光谱分析提供了依据     

Nucleophilic substitution at phosphorus: stereochemistry and mechanisms

This review is devoted to the stereochemistry of nucleophilic substitution reactions at phosphorus. The study of the reactions of phosphoryl group transfer is important for biological and molecular chemistry. The stereochemistry and mechanisms of S_N1(P) monomolecular and S_N2(P) bimolecular nucleophilic substitution reactions of organophosphorus compounds are discussed. It has been shown that hydrolysis of many natural phosphates proceeds according to the monomolecular S_N1(P) mechanism via the formation of metaphosphate intermediate (PO₃^?). S_N2(P) nucleophilic substitution at chiral trivalent or pentavalent phosphorus compounds proceeds via the formation of penta-coordinated transition state or pentacoordinate intermediate.     

P—矩阵法测定安钠咖注射液中两组分的含量

本文采用Ｐ－矩阵法不经分离同时测定安钠咖注射液中咖啡因和苯甲酸钠的含量。计算程序用ＢＡＳＩＣ语言编制。咖啡因和苯甲酸钠的平均回收率分别为１００．０和９９．９５％，变异系数分别为０．４０％和０．６５％，方法简便，快速，样品测定结果与药典法测得结果基本一致。