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本文提出用 2,2′——二氯——4,4′——二硝基重氮氨基苯[Ⅰ]分光光度测定痕量汞的新方法。方法基于在非离子表面活性剂吐温20存在下,(Ⅰ)的红色被汞(Ⅱ)减退,减退的吸光度与汞(Ⅱ)量成正比。适宜的条件如下:痕量汞可以在含有汞(Ⅱ)摩尔数的3.5倍以上的[Ⅰ],1.0—2.5毫升2%吐温20,2.5—4.0毫升乙醇,溶液的 pH 为9.8—10.9的25毫升溶液中于550纳米测定,0至13微克汞(Ⅱ)/25毫升服从比尔定律,Sandell 灵敏度为1.3×10~(-3)μg/cm~2(相当的摩尔系数为1.54×10~5)。吸光度至少在12小时内不变。在测定条件下,汞(Ⅱ)与(Ⅰ)之化合比为1:3。考查了32种阳离子和11种阴离子对测定的影响。复杂的工业废水中 PPb 级汞和复杂锌精矿中 ppm 级汞,经适当分离后,用本法测定,结果令人满意。
In this paper, a new spectrophotometric method for the determination of trace mercury with 2,2’-dichloro-4,4’-dinitro-diazaminobenzene [I] is proposed. The method is based on the fact that the red color of (I) is reduced by mercury (II) in the presence of the non-ionic surfactant Tween 20, and the diminished absorbance is proportional to the amount of mercury (II). The suitable conditions are as follows: Trace mercury can be used in the presence of [I] in an amount 3.5 times the number of moles of mercury (II), 1.0-2.5 ml of 2% Tween 20, 2.5-4.0 ml of ethanol and the pH of the solution is 9.8-10.9 Beer’s Law, Sandell’s sensitivity is 1.3 × 10 -3 μg / cm 2 (equivalent Molar coefficient is 1.54 × 10 ~ (-1)) at 25 ° C in 550 nm and 0 to 13 μg Hg (II) / 25 ml. 5). Absorbance does not change for at least 12 hours. Under the conditions of determination, the ratio of mercury (Ⅱ) to (Ⅰ) is 1: 3. The effect of 32 cations and 11 anions on the assay was examined. PPb mercury in complex industrial waste water and ppm-level mercury in complex zinc concentrate, after appropriate separation, are determined by this method and the results are satisfactory.