双环己酮草酰二腙光度法测定合金中高含量铜

以双环己酮草酰二腙（BCO）光度法快速测定合金中高含量铜，并对最佳显色条件进行了探讨。结果表明：在pH 8.5~10.0的氨水-氯化铵缓冲溶液中，铜与BCO形成蓝色络合物，该络合物的最大吸收波长为600 nm；BCO浓度为0.1 g/L；显色温度为20 ℃；显色时间是10 min；柠檬酸铵用量为1 mL。铜在0.4~4.0 μg/mL范围内符合比尔定律，表观摩尔吸光系数ε=1.6×10⁴ L·mol^-1·cm^-1。方法应用于高温合金及铜合金标准样品中高含量铜的测定，测定值与认定值相符，相对误差＜1.0%，相对标准偏差＜6.5%。

Determination of high content copper in alloys by bis-cyclohexanone oxalydihydrazone spectrophotometric method

High copper content in alloys determined by bis-cyclohexanone oxalydihydrazone spectrophotometric method rapidly was studied in this paper and the optimum chromogenic conditions were discussed. Copper and BCO form a blue complex in ammonia-ammonium chloride buffer solution at pH 8.5-10.0. The maximum absorption wavelength was 600 nm. The concentration of BCO was 0.1 g/L. The coloration temperature was 20 ℃. The coloration time was 10 min. The dosage of ammonium citrate was 1 mL. Beer’s law was obeyed in the range of 0.4-4.0 μg/mL for copper. And the apparent molar absorptivity (ε) was 1.6×10⁴ L·mol^-1·cm^-1. This method was applied to determine high content copper in high temperature alloy and copper alloy CRMs. Its relative error was smaller than 1% and the RSD was less than 6.5%.