过氧化钠熔融-电感耦合等离子体质谱法测定锡矿石中锡

Determination of tin in tin ore by inductively coupled plasma mass spectrometry after fusion with sodium peroxide

锡矿石中锡的测定主要采用碘量法(铝片还原),该方法操作相对繁琐,分析数据精密度较低。基于锡矿石具有不易溶于酸、易溶于碱的特点,实验采用过氧化钠熔融样品,盐酸提取,电感耦合等离子体质谱法(ICP-MS)测定锡矿石中锡。研究了碱融熔剂用量、熔样时间、同位素选择、仪器工作参数等实验条件,确定了以过氧化钠作为熔剂、样品/熔剂质量比1∶6、15 min熔解时间、40%盐酸提取酸度的最佳熔样条件。对所建立的分析方法进行了方法验证,确定方法检出限为13.87 mg/kg,标准物质测定的相对误差均小于3%,12次平行测定的相对标准偏差(RSD,n=12)小于2%,对标准物质及实际样品的测定结果满足锡矿石中锡含量的测定要求。

Tin in tin ore is usually determined by iodometry(reduction of aluminum flake).The operation of this method is relatively tedious and the precision of analytical results is relatively low.Based on the characteristics that tin ores are hardly dissolved in acid but easily dissolved in alkali,the tin ore sample was fused with sodium peroxide in experiments followed by leaching with hydrochloric acid.Then the content of tin in tin ore was determined by inductively coupled plasma mass spectrometry.Experimental conditions were investigated,including the dosage of alkali fluxing agent,the fusion time,the selection of isotope and the working parameters of instrument.The optimal fusion conditions were obtained as follows:the flux was sodium peroxide;the mass ratio of sample and flux was 1∶6;the fusion time was 15 min;the leaching solution was 40%HCl.The established analysis method was validated.The limit of detection was 13.87 mg/kg.The relative errors in determination of the standard materials were less than 3%.The relative standard deviation(RSD,n=12)was less than 2%.The determination results of standard substance and actual samples could meet the determination requirements of tin content in tin ores.