二乙基二硫代氨基甲酸银比色测定砷的方法系在碘化钾和氯化亚锡存在下,用金属锌将砷还原为砷化氢,它与二乙基二硫代氨基甲酸银吡啶溶液反应,生成红色胶状银,以此进行比色测定砷。此法具有较高的选择性和灵敏度,故广泛用于痕量砷的测定,但其缺点是使用具有恶臭和毒性的吡啶。为了克服此缺点,近三十多年来,有很多人从事吡啶代用品的研究,先后试验过几十种有机碱,其中效果较好的有马钱子碱、麻黄素、三乙胺和三乙醇胺等的氯仿溶液,它们的灵敏度均不如吡啶,但无恶臭,不过马钱子碱毒性较大,三乙胺仍有臭味,而三乙醇胺-氯仿吸收液不够稳定。我们发现二苯胍的氯仿溶液也有和吡啶相 Silver diethyldithiocarbamate silver colorimetric determination of arsenic in the Department of potassium iodide and stannous chloride in the presence of zinc with arsenic reduction of arsenic, which is silver dithiocarbamate pyridine solution Reaction, generate red colloidal silver, colorimetric determination of arsenic. This method has a high selectivity and sensitivity, it is widely used in the determination of trace amounts of arsenic, but the disadvantage is the use of odorous and toxic pyridine. In order to overcome this shortcoming, in the recent three decades, many people have been engaged in the research of pyridine substitutes. They have tested dozens of organic bases, of which brucine, ephedrine, triethylamine and tris Ethanolamine and the like chloroform solution, their sensitivity is not as good as pyridine, but no malodor, but greater toxicity brucine, triethylamine still smell, and triethanolamine - chloroform absorption solution is not stable enough. We found that diphenylguanidine in chloroform also has a pyridine phase