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在弱碱性溶液中,PAN能与微量铅反应生成不溶于水的红色络合物,用有机溶剂萃取后可以用分光光度法测定铅的含量,但是这种方法不仅手续麻烦,而且容易引起误差。我们用Tween—20作为增溶剂,令不溶性络合物直接增溶于胶束中,然后立即进行分析。在PH大于9.5,波长为560nm,红色络合物在20分钟内能保持稳定,克分子消光系数为1.4×10~4摩尔~(-1).厘米~(-1),灵敏度为0.005微克·厘米~(-2)。对十一种常见离子的干扰进行了试验,祗有五种离子有干扰作用,但加入掩蔽剂均可达到掩蔽的目的。
In weakly alkaline solution, PAN reacts with trace amounts of lead to form water-insoluble red complexes. After extracting with organic solvents, the content of lead can be determined spectrophotometrically. However, this method not only causes inconvenience but also easily causes errors . We used Tween-20 as a solubilizer to solubilize the insoluble complex directly in micelles and analyzed immediately. At PH> 9.5 and wavelength of 560 nm, the red complex remained stable within 20 minutes with a molar extinction coefficient of 1.4 × 10 ~ 4 mol -1 cm -1 with a sensitivity of 0.005 μg · Cm ~ (-2). The interference of eleven kinds of common ions has been tested, only five kinds of ions have the interference effect, but the masking agent can be added to achieve the purpose of masking.