| 摘要 |
A pre-treatment method for analyzing Cr 6+ in a glass composition is provided to analyze a trace amount of Cr 6+ to the ppm level with less error. A pre-treatment method for analyzing Cr 6+ in a glass composition includes the steps of: (i) mixing ammonium hydrogen difluoride(NH4HF2), a diluted sulfuric acid solution(con H2SO5:water=1:1(v/v)), and water to obtain a decomposition solution with pH 3-3.5, adding a sample to the decomposition solution, and stirring the admixture for 15-30 minutes to perform a first decomposition; (ii) adding boric acid to the first decomposed products of the step (i), stirring the admixture for 10-15 minutes, cooling the admixture to ambient temperature, thereto adding 0.2 N of sulfuric acid, stirring the admixture for 5-15 minutes, and cooling the stirred material to ambient temperature; (iii) adding water to the solution of the step (ii) to make up to 100 mL; and (iv) separating 20 mL of the solution from 100 mL of the solution, thereto adding solutions of ethylenediaminetetraacetic acid and diphenylcarbazide, and thereto adding 0.2 N of sulfuric acid to make up to 100 mL.
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