一、试验 1.吸收峰 在50ml容量瓶中,加入锡20μg,CTMAB(0.04％)4ml,邻苯二酚紫(0.04％)4ml,用水稀释至刻度,摇匀。参比液与上述同样操作,在加入邻苯二酚紫溶液之前滴入EDTA(5％)5滴。用1cm比色皿比色,测定吸光度,发现在660～662nm波长处有一最大吸收峰(图1)。本方法取660nm为吸收波长。 First, the test 1. Absorption peak in 50ml volumetric flask, add tin 20μg, CTMAB (0.04%) 4ml, catechin violet (0.04%) 4ml, diluted with water to the mark, shake. The reference solution was treated in the same manner as described above, and 5 drops of EDTA (5%) were added dropwise before the catechol violet solution was added. With 1cm cuvette colorimetric determination of absorbance, found in the 660 ~ 662nm wavelength at a maximum absorption peak (Figure 1). The method to take 660nm for the absorption wavelength.