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在含ＥＤＴＡ、溴代苯羟乙酸（Ｂｒ－ＢＨＡ）的硫－磷混酸介质中，钼（Ⅵ）、钨（Ⅵ）－Ｂｒ－ＢＨＡ络合物分别在- ０.５０Ｖ和-０．８７Ｖ（ｖｓ．ＳＣＥ）处产生不太灵敏的极谱电流。加入ＮａＣｌ_３后，产生灵敏催化电流［比在苯羟乙酸（ＢＨＡ）体系分别增敏２．３倍和３倍］，峰电位（Ｅｐ）分别移至－０.４４Ｖ和－０.７８Ｖ。系统研究了十余种易质子化有机染料和八种阳离子表面活性剂对上述催化电流进一步增敏效应，其中以亚甲蓝（ＭＢ）为最佳。无ＮａＣｌＯ_３时，加入 ＭＢ，原络合电流略有所降低， Ｅｐ无明显变化。但当加入 ＮａＣｌＯ_３后，极谱催化电流得到进一步增敏， Ｅｐ分别为-０.４３Ｖ和-０．８３Ｖ。钼（Ⅵ）、钨（Ⅵ）测定的线性范围分别为２×１０~(－９)～４×１０~(－７)和５×１０~(-１０)～２×１０~(-８)ｍｏｌ／Ｌ，检出限分别为１×１０~(-９)和３×１０~(－１０)ｍｏｌ／Ｌ。大多共存离子（阳离子４４种，阴离子１０种）不干扰测定，［Ｍｏ（Ⅵ）］：［Ｗ（Ⅵ）］或反之，为１：２５００互不干扰。方法已用于合金、纯铁等样品中铝、钨的同时直接测定，结果满意。有关络合物、电极反应和增敏机理等研究结果，将另文发表。
The molybdenum (Ⅵ) and tungsten (Ⅵ) -Br-BHA complexes in the sulfur-phosphorus mixed acid medium containing EDTA and Bromobenzene glycolic acid (Br-BHA) were at -0.50 V and -0.87 V vs.SCE) produces a less sensitive polarographic current. The addition of NaCl_3 resulted in a sensitive catalytic current (2.3 and 3 times more sensitive than that of BHA), and the peak potentials (Ep) shifted to -0.44V and -0.78V, respectively. More than ten kinds of easily protonated organic dyes and eight kinds of cationic surfactants were studied systematically to further sensitize the above catalytic current, of which methylene blue (MB) was the best. Without NaClO_3, adding MB, the original complex current slightly reduced, Ep no significant change. However, when NaClO_3 was added, the polarographic catalytic current was further sensitized with Ep values of -0.43V and -0.83V, respectively. The linear ranges of molybdenum (Ⅵ) and tungsten (Ⅵ) were 2 × 10 -9 ~ 4 × 10 -7 and 5 × 10 -10 ~ 2 × 10 -8, respectively. mol / L, the detection limits were 1 × 10 -9 and 3 × 10 -10 mol / L, respectively. Most of the coexisting ions (44 cations and 10 anions) do not interfere with the determination. [Mo (VI)]: [W (VI)] or vice versa, do not interfere with each other at 1: 2500. The method has been applied to the direct determination of aluminum and tungsten in the samples such as alloy and pure iron with satisfactory results. Relevant research results on complexation, electrode reaction and sensitization mechanism will be published separately.