本文试验了苯基荧光酮-曲通X-100直接光度法测定碳钢及低合金钢中微量锡的条件,结果表明,在0.25—0.75mol/L硫酸介质中,锡(Ⅳ)离子与苯基荧光酮、曲通X-100形成有色络合物,表观摩尔吸光系数为1.25×10~5;络合物吸光度至少4小时不变;锡量在0—16微克/25毫升范围内符合比尔定律。在拟定条件下,共存离子的允许量(毫克)为:Fe~(3+)(10), In this paper, the conditions for the determination of trace tin in carbon steel and low alloy steel by phenylfluorone-Qu Triton X-100 direct spectrophotometry were studied. The results showed that tin (Ⅳ) ion and benzene Fluoroketone, Triton X-100 formed a colored complex, the apparent molar absorptivity was 1.25 × 10 ~ 5; the absorbance of the complex was unchanged for at least 4 hours; the amount of tin was within the range of 0-16 μg / 25 ml Bill’s law. Under the proposed conditions, the allowable amount of coexisting ions (mg) is: Fe ~ (3 +) (10),