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本文提出了一个加热气化原子吸收法测定地质样品中痕量汞的方法。与日本岛津公司的汞分析方法比较,灵敏度提高了10倍。同时使批量分析速度提高,成本降低。由于本法有效地排除了干扰,它比目前国内外广泛采用的冷原子吸收法更适用于成份复杂的地质样品中痕量汞的测定。而且具有更高的灵敏度和更宽的工作曲线范围。在低温加热下,以王水分解样品,然后制成含0.025%重铬酸钾和10%王水的汞试液。加入EDTA和柠檬酸钠后,在pH4.7条件下,用双硫腙四氯化碳萃取分离大部分干扰离子将有机相于瓷舟中晾干,再放瓷舟于石英加热管中加热分解,使汞成原子蒸气被导入原子吸收分光光度计的吸收管,测量其吸收值。吸收采用2537的共振线。本方法的绝对灵敏度为1.3ng/1%。六次平行测定的相对标准偏差为2.8%。用本法测定几个地质样品和其它方法对照,结果令人满意。
In this paper, a method for the determination of trace mercury in geological samples by heating gasification atomic absorption spectrometry is proposed. Compared with Japan’s Shimadzu mercury analysis method, sensitivity increased by 10 times. At the same time to speed up the bulk analysis, lower costs. Due to the effective elimination of interference, this method is more suitable for the determination of trace mercury in complex geological samples than the widely used cold atomic absorption method at home and abroad. And with higher sensitivity and wider working curve range. Under low temperature heating, the sample was decomposed with aqua regia and then made into a mercury test solution containing 0.025% potassium dichromate and 10% aqua regia. After adding EDTA and sodium citrate, under the condition of pH4.7, extract and disrupt most of the interfering ions by dithizone carbon tetrachloride, dry the organic phase in a porcelain boat, then heat the porcelain boat in a heating tube of quartz , So that mercury vapor into the atomic absorption spectrophotometer absorption tube, measuring its absorption value. Absorb 2537 resonance line. The absolute sensitivity of this method is 1.3 ng / 1%. The relative standard deviation of the six parallel determinations was 2.8%. Using this method to determine several geological samples and other methods of control, the results are satisfactory.