密闭酸溶-电感耦合等离子体原子发射光谱法测定钼矿中钼和铜
ICP-AES Determination of Molybdenum and Copper in Molybdenum Ores with Acid Dissolution of Sample in Closed Vessel
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摘要: 经粉碎和烘干的钼矿样品(0.1 g)于密闭的聚四氟乙烯消解杯中用盐酸、硝酸及氢氟酸,在中温电热板上加热3 h,使之溶解。启盖后加入高氯酸1 mL冒烟至近干,用6 mol·L-1盐酸溶液5 mL溶解盐类,加入10 mg·L-1铑(Ⅲ)溶液5.00 mL作内标(用其谱线343.489 nm),移入50 mL容量瓶中加水至刻度。选择波长为202.030 nm和327.396 nm的谱线分别作为测定钼及铜的分析线。测得以上2种元素的检出限(3s)分别为3.8,7.1 μg·g-1。对方法的精密度也做了试验,测得钼及铜测定值的相对标准偏差(n=12)依次为1.3%~3.2%和2.4%~4.6%范围内。应用此方法分析了3件钼矿标准物质,所得钼及铜的测定结果与认定值一致。Abstract: The ground and dried molybdenum ore sample (0.1 g) was digested with HCl, HNO3 and HF in a closed PTFE digestion vessel by heating for 3 h on a hot plate at medium temperature. One mL of HClO4 was added and fumed to near dryness. The residue was taken up with 5 mL of 6 mol·L-1 HCl and diluted to 50 mL with water in a volumetric flask after adding 5.0 mL of 10 mg·L-1 Rh(Ⅲ) solution as internal standard (using its spectral line of 343.489 nm). The spectral lines of 202.030 nm and 327.396 nm were selected as analytical spectral lines for Mo and Cu respectively. Detection limits (3s) found for the 2 elements were 3.8, 7.1 μg·g-1 respectively. Precision of the method was tested, giving values of RSD′s (n=12) in the ranges of 1.3%-3.2% (for Mo) and of 2.4%-4.6% (for Cu). Three CRM′s of molybdenum ores were analyzed by the present method, values of Mo and Cu found were in consistency with the certified values.