Determination of Iodine in Soil Samples by Signal Enhanced Inductively Coupled Plasma-Mass Spectrometry using Methane Gas Addition after Ammonium Hydrogen Fluoride Digestion
A rapid and high sensitive method has been developed to quantify iodine concentrations in soil samples by inductively coupled plasma-mass spectrometry(ICP-MS).The method is based on an ammonium hydrogen fluoride(NH4HF2)semi-open digestion and signal enhancement by adding methane gas during analysis.Fifty mg sample of soils can be completely digested by using 250 mg of NH4 HF2 at 220 ℃ for 3h and no volatilization loss of iodine was observed.Methane gas,used as a matrix modifier,is online mixed with the sample aerosols before introducing to the ICP plasma.Through careful optimization of the methane gas and carrier gas flow rates,2.4 times increasement in the iodine sensitivity was obtained.Under the optimized operational conditions,the limit of detection(LOD,3a)of iodine is 0.012 μg/g.The measured iodine results for nineteen national soil standard reference materials are in good agreement with the certified values,further highlihgting the reliability and analytical capabilities of our new approach.
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维普
