Determination of iodide in urine using electrospray ionization tandem mass spectrometry

摘要

A rapid and sensitive electrospray ionization (ESI) tandem mass spectrometry (MS-MS) procedure was developed for the determination of iodide (I~-). A gold (Au) and I~- complex was formed immediately after the addition of the chelating agent NaAuCl_4 to I~- solution, and was extracted with methyl isobutyl ketone. One to five microliters of the extract were injected directly into an ESI-MS-MS instrument. I~- quantification was performed by selecting reaction monitoring of the product ion I~- at m/z 127 derived from the precursor ion ~(197)AuI_2~- at m/z 451. I~- concentration was measured in the quantification range from 10~(-7) to 10~(-5) M using 50 μL of solution within 10 min. Iodate was reduced to I~- with ascorbic acid and determined. I~- concentration in reference urine 2670a was measured after treatments.