微波消解罐铬残留清洗方法的探讨

Investigation on cleaning methods for chromium residue in microwave digestion tanks

目的:确定微波消解罐的最佳清洗方法。方法:分别选用5种清洗方法对消解了不同样品(铬浓度分别为0.7,2.7,4,40 mg.kg-1)的消解罐进行清洗,采用微波消解以原子吸收分光光度计对清洗后消解罐中残留铬的含量进行测定。结果:"盐酸溶液(1→2)浸泡1 h,再用硝酸浸泡1 h,去离子水清洗3遍"或"用硝酸溶液(1→5)浸泡8～12 h,用去离子水清洗3遍"都可以将消解罐中残留的铬清洗干净。结论:"盐酸溶液(1→2)浸泡1 h,再用硝酸溶液(1→2)浸泡1 h,去离子水清洗3遍"的清洗方法,既可以节约时间,又可以保证后期实验结果的准确性,可用于铬测定过程中微波消解罐的清洗。

Objective：To determine the best cleaning method for microwave digestion tanks. Methods： Five clean- ing methods were selected to clean the digestion tank that had been used for different samples （with the chromium concentration of 0. 7,2. 7,4 and 40 mg. kg^-1）. Trace chromium in the digestion tanks was analyzed by microwave digestion and graphite furnace atomic absorption spectrometry. Results： The chromium residue in the digested tanks can be cleaned by two cleaning methods as ＂soak for 1 h with hydrochloric acid solution（1→2） ,soak for 1 h with nitric acid solution（1→2） ,then wash three times with deionized water＂ and ＂soak for 8 →12 h with nitric acid so- lution （1→5） , wash three times with deionized water＂. Conclusion： The cleaning methods of ＂soak for 1 h with hy- drochloric acid solution （1→2）, soak for 1 h with nitric acid solution（ 1→2 ） , then wash three times with deionized water＂ not only can save time hut also ensure the accuracy of the post - experimental results,which can be used for microwave digestion tanks cleaning during chromium determination process.