Carius管溶样-标准加入电感耦合等离子体质谱法测定土壤中碘

Precise Determination of Iodine in Soil Samples by ICP-MS with Carius Tube and Standard Addition Method

建立了利用Carius管提取与标准加入电感耦合等离子体质谱法测定土壤中碘的方法。样品用φ=10%的NH.H2O溶液于密封的Carius管中150℃提取4 h,溶液适当稀释后离心分离沉淀,取出5等份样品上清液,分别加入不同浓度的碘标准储备液,用电感耦合等离子体质谱法测定溶液中的碘,以126Te作为内标。应用该方法分析了土壤国家一级标准物质GBW07404、GBW 07406、GBW 07407中碘的含量分别为(9.58±0.02)μg/g、(19.83±0.01)μg/g和(18.88±0.03)μg/g。分析结果与标准值相符。碘的检出限为0.02μg/g。

Iodine in soil samples were extracted with 10% NHa · H2O in Carius tube for 4 hours at 150℃. After properly diluted, the solution was separated centrifugally. Then five equal parts of elutate were taken out and iodine standard solution with different concentration was added, then directly determined by inductively coupled plasma mass spectrometry with standard addition method. ^126Te was used as internal standard to compensate for matrix effect and the instrumental drift. The established method was used to analyze Chinese soil certified reference materials including GBW 07404, GBW 07406 and GBW 07407. The results were （9.58 ± 0.02 ） μg/g, （ 19.83 ±0.01 ） μg/g and （18.88±0.03） μg/g, respectively. The iodine concentrations were in a good agreement with the certified values within the permitted error. The detection limit for iodine was 0.02μg/g.