title: Development and validation of an assay for iodide in serum using ion chromatography with pulsed amperometric detection.
abstract: We developed and validated an ion chromatography method to assay iodide in serum sampled from rats and rabbits that had been exposed to iodomethane. Iodomethane is of interest because it is a volatile liquid pre-plant soil crop protection fumigant that has been proposed as a non-ozone-depleting alternative to methyl bromide. Serum was prepared from whole blood collected on wet ice at the time of sacrifice and kept frozen at less than -65 degrees C. For analysis, serum samples were thawed unassisted at ambient temperature. Proteins were separated from the serum samples by ultrafiltration. A 100-microl filtered serum sample was then injected into the ion chromatograph without additional sample preparation. Iodide was separated in <20 min by anion-exchange chromatography using a 25-mM nitric acid eluent. The analyte of interest was detected by pulsed amperometry using a silver working electrode. The method showed linear response over the concentration range of 100 to 5000 ng/ml iodide (r2>.998) with a lower limit of quantitation of 100 ng/ml iodide. The accuracy of the procedure, determined by spiked recovery measurements at 100 ng/ml iodide, was between 90 and 110%. A method detection limit of 20 ng/ml for iodide in serum samples was demonstrated using the method of standard additions.
authors.affiliation: MPI Research, Inc., State College, Pennsylvania 16801, USA. edward_kaiser@yahoo.com
authors.forename: Edward
authors.initials: E
authors.lastname: Kaiser
authors.forename: Lydia
authors.initials: L
authors.lastname: Shaffer
authors.forename: John M
authors.initials: JM
authors.lastname: Flaherty
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Rohrer
authors.forename: Matthew W
authors.initials: MW
authors.lastname: Himmelstein
mesh_terms: D000818:Animals; D002852:Chromatography, Ion Exchange / Q000295:instrumentation / Q000379:methods / Q000592:standards; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods / Q000592:standards; D006847:Hydrocarbons, Iodinated / Q000032:analysis / Q000097:blood; D007454:Iodides / Q000032:analysis / Q000097:blood*; D008297:Male; D011817:Rabbits; D051381:Rats; D021241:Spectrometry, Mass, Electrospray Ionization / Q000295:instrumentation / Q000379:methods / Q000592:standards
chemical_list: D006847:Hydrocarbons, Iodinated; D007454:Iodides; C014055:methyl iodide