Comparison of two different inductively coupled plasma mass spectrometric procedures and high-performance liquid chromatography with electrochemical detection in the determination of iodine in urine

Abstract

A comparison between two ICP-MS methods and HPLC with electrochemical detection (ED) for the determination of iodine is described. The first ICP-MS method involves 10-fold dilution with water using Rh as internal standard and the calibration graph was obtained with a synthetic urine. In the second ICP-MS method the sample preparation provided a 5-fold dilution with water using In as internal standard and adding nitric acid and the calibration graph was obtained by making additions to a pool of human urine samples. In the HPLC method, the urine was previously purified from organic substances through an SPE C₁₈ column and the final portion was collected. The chromatographic column used was a C₁₈ reversed-phase column and a silver working electrode was used versus a Pd/Pt reference electrode for ED. The calibration graph was obtained with a synthetic urine. The results show that the two ICP-MS methods are comparable in terms of analytical parameters such as precision and limit of detection. Good agreement between both ICP-MS procedures and HPLC–ED was also obtained, although the limit of detection was higher in HPLC–ED and the linear dynamic range was wider in both ICP-MS methods.