DIFFERENTIAL PULSE VOLTAMMETRIC DETERMINATION OF 3,3''''5,5''''-TETRAMETHYLBENZIDINE AND ITS ANALOGUES WITH A GLASSY CARBON ELECTRODE

The differential pulse voltammetric (DPV) method-with a glassy carbon electrode was used for the determination of 3,3' 5,5'-tetramethy lbenzidine (TMB), o-tolidine and benzidine in the acidic media. The pulse amplitude, interval time and scan rate of DPV are optimized to be 50 mV, 0. 5 s and 10 mV/s, respectively. The peak current, is proportional to the concentration of TMB and its analogues, the linear range is from 10~(-6)mol/l to 10~(-4)mol/l. The electrochemical behaviour of the compounds is discussed. The chemical poisons can be determined directly, or indirectly by the extraction in the waste water of chemical industry and laboratory.     

桉叶素、樟脑、薄荷脑、水杨酸甲酯混合物的气相色谱分析

某些保键药物、食品中含有桉叶素、薄荷脑、樟脑等物质,对于这些物质的两种或三种混合物的气相色谱分析已有不少报导。文献报导用气相色谱法测定药物软膏中樟脑、薄荷脑和水杨酸甲酯的含量,提出用苯甲醇作内标,用程序升温的方法。本文采用苯甲酸乙酯作内标,以恒温操作法,用国产色谱仪对上述混合物进行定量分析,方法简便,同样取得满意的结果。     

[CuAc_2(dmpzH)_2]·2CH_3OH的合成与晶体结构(dmpzH=3,5-二甲基吡唑)

在回流条件下,3,5-二甲基吡唑(dmpzH)与Cu(Ac)2·H2O在甲醇中反应得到化合物[Cu(Ac)2(dmpzH)2]·2CH3OH(1.2CH3OH),该化合物通过元素分析、红外光谱等表征.X射线衍射法测得该晶体属于正交晶系,空间群为Pbcn,晶胞参数:a=1.565 1(3)nm,b=1.083 4(2)nm,c=1.124 0(2)nm,α=β=γ=90°,V=1.905 9(6)nm3,C15H26CuN4O5,Mr=405.95,Dc=1.415 g/cm3,Z=4,F(000)=852,R1=0.087 8,wR2=0.230 9,S=1.07 7.每个铜原子与两个氧原子和两个氮原子配位,形成一个扭曲的四面体配位结构.Cu-N、Cu-O键长分别为0.198 4(5)nm和0.200 5(4)nm.     

对甲苯磺酸／甲醇试剂用于气相色谱法中羧酸甲酯的衍生化反应

羧酸和甲醇在酸的催化下进行酯化反应,是气相色谱衍生化反应的常见方法。常用方法有CH_3OH～HCl法,CH_3OH_3OH—H_2SO_4法,CH_3OH—BF_3法,这些方法都比较成熟,在实际应用中也各具特点。曾有人用对甲苯磺酸(P—TSA)作为羧酸酯化反应的催化剂,该法对一些复杂的有机酸和醇反应转化率较高,并有不少这方面的合成专利和报导。本文探讨将PTSA—CH_3OH法用于色谱分析的新的甲酯化方法。采用某些有机酸和甲醇反应,考察P—TSA的催化效能,实验结果表明:P—TSA对三类羧酸的甲酯化反应都有较好的催化效果,尤其苯甲酸、水杨酸、邻氯苯甲酸等芳香酸用CH_3OH—PTSA法优于CH_3OH—HCl,CH_3OH—BF_3法。     

DIFFERENTIAL PULSE VOLTAMMETRIC DETERMINATION OF 3,3＇ 5,5＇-TETRAMETHYLBENZIDINE AND ITS ANALOGUES WITH A GLASSY CARBON ELECTRODE

The differential pulse voltarametric ( DPV ) method with a glassy carbon electrode was used for the determination of 3,3‘ 5,5‘-tetramethy lbenzidine ( TMB ) , o-tolidine and benzidine in the acidic media. The pulse amplitude, interval time and scan rate of DPV are optimized to be 50 mV, 0.5 s and 10 mV/s, respectively, The peak current is proportional to the concentration of TMB and its analogues, the linear range is from 10^-8mol/l to 10^-4 mal/l, The electrochemical behaviour of the compounds is discussed, The chemical poisons can be determined directly, or indirectly by the extraction in the waste water of chemical industry and laboratory,