引言氯磺酚S已应用于微克量锆、铌、钼和钨的测定,这是一种值得注意的显色剂。Zenki指出:就变色酸双偶氮的衍生物言,能与钒离子显色的须有硝基位于偶氮基团的对位上。因而氯磺酚S及其衍生物无此反应。这一论点是缺乏说服力的。因氯磺酚S的螯合显色基团缺乏选择性,既能与铌、锆、钼和钨显色,而四者的分析化学性质又与钒很接 Introduction Chlorosulfonol S has been used in the determination of trace amounts of zirconium, niobium, molybdenum and tungsten, which is a noteworthy developer. Zenki states that in the case of chromogenic acid disazo derivatives, the nitro group which can be colored with vanadium ions is located in the para position of the azo group. Thus, there is no reaction of chlorosulfonol S and its derivatives. This argument is not convincing. Due to the lack of selectivity of the chelate chromophores of the chlorosulfonates S, both of them develop coloration with niobium, zirconium, molybdenum and tungsten, and the analytical chemistry of the four is very close to that of vanadium