微量砷的测定一般采用砷钼蓝光度法和二乙硫代甲酸银光度法。文献在报导磷钼杂多酸与染料所形成的络合物研究中,指出砷有类似的显色反应而有干扰,并表明了磷钼酸与孔雀绿形成的络合物在水相中是不稳定的。文献报导了结晶紫光度法测定砷,是利用砷钼酸与染料形成色淀后加丙酮混溶有机相后比色,有重现性差等问题存在,并也只限于纯溶液试验。鉴于砷钼酸与磷类似和碱性染料形成的络合物在水相中是不稳定的,我们把砷钼酸转换成砷钼蓝后,再用丁基罗丹明B(λ_(max)590nm)、乙基紫(λ_(max)620nm)、孔雀绿等显色,在水相中就具有一定的稳定性。其灵 Determination of trace arsenic commonly used arsenic molybdenum blue photometry and silver thiosulfate two photometry. Literature reported in the complex formed by the phosphomolybdic heteropolyacid and the dye, pointed out that arsenic has a similar color reaction with interference, and shows that the phosphomolybdic acid and malachite green complex formed in the aqueous phase is unstable. Literature reported the determination of arsenic by crystal violet spectrophotometry, is the use of arsenic molybdate and dye lake after the formation of color mixed acetone-miscible organic phase, with poor reproducibility problems exist, and is limited to pure solution test. Since the complexes of arsenic molybdate with phosphorus-like and basic dyes are not stable in the aqueous phase, we converted arsenomolybdate to arsenic-molybdenum blue and then treated with rhodamine B (λ max 590 nm ), Ethyl violet (λ max 620nm), malachite green and other color, in the water phase has a certain stability. Its spirit