表面活性剂增敏结晶紫褪色光度法测定板蓝根中痕量铜

PHOTOMETRIC DETERMINATION OF TRACES OF COPPER IN RADICES ISATIDES SEU BAPHICACANTHI BY CATALYTIC OXIDATIVE COLOR-FADING OF CRYSTAL VIOLET

在磷酸介质及表面活性剂存在下,95 ℃恒温水浴中,铜(Ⅱ)催化溴酸钾氧化结晶紫褪色.据此建立了测定痕量铜的方法.铜(Ⅱ)浓度的线性范围为0～15 mg·L-1,最大吸收波长为590 nm,检出限为8.3×10-7g·L-1.方法简单快速、选择性好,用于测定板蓝根(RISB)中铜时,测得结果与AAS法的结果一致,所得结果的RSD值均小于2.5%,回收率在105%～106%.

In a dilute phosphoric acid medium and in the presence of CTMAB, the oxidation of crystal violet by bromate was catalyzed by trace amounts of Cu（ Ⅱ ） heated at 95℃ in a water bath, resulting a color-fading of the crystal violet. It was found that the intensity of color-fading （△A） kept a linear relationship with the concentration of Cu（ Ⅱ ） ion in the range from 0 to 15 mg per L of solution. The absorbance was measured at 590 nm which is the absorption maxima of crystal violet. Detection limit of this reaction was found to be 8. 3× 10^-7g · L^-1. The results obtained in the application of this method to the analysis of radices isatides seu baphicacanthi were in consistency with those obtained by the AAS method, and the RSD＇s found were less than 2.5% and recoveries were in the range of 105% to 106%.