Determination of 2,4,6-triiodophenol and its metabolites in human urine by anion-exchange chromatography with ICP-MS detection

Abstract

An analytical method using high-performance liquid chromatography (HPLC) coupled to inductively coupled plasma mass spectrometry (ICP-MS) was developed for the separation and determination of iodophenol compounds in human urine samples. The advantages of using highly-sensitive ¹²⁷I detection provided by ICP-MS for the speciation of 2,4,6-triiodophenol, 4-iodophenol and 2-iodophenol are shown in this work. 2,4,6-triiodophenol is also referred to as Bobel-24, an anti-inflammatory. Chromatographic conditions were optimized using UV absorption at 254 nm and ICP-MS detection of ¹²⁷I and a comparative study between these two detection systems was developed. The separation of iodophenol species was studied by two different chromatographic modes: reversed-phase and anion-exchange chromatography. Complete chromatographic resolution of the iodophenol species was obtained in 100% aqueous phase solution using gradient elution of NaOH (50 mmol l⁻¹) and NaOH (50 mmol l⁻¹) with hexadecyltrimethylammonium bromide (CTAB). Total resolution was obtained in a minimal retention time of 7 min. Since the separation of the iodophenol species was performed in an aqueous mobile phase, high sensitivity was obtained with the ICP-MS instrument. The detection limits obtained were between 0.08–0.22 µg l⁻¹ as iodophenol compounds. On the other hand, the detection limits obtained with UV detection were 300–325 times higher with ICP-MS. Finally, the analytical methodology was applied for the determination of iodophenols in human urine.