title: A robust method for iodine status determination in epidemiological studies by capillary electrophoresis.
abstract: Iodine deficiency is the most common preventable cause of intellectual disabilities in children. Global health initiatives to ensure optimum nutrition thus require continuous monitoring of population-wide iodine intake as determined by urinary excretion of iodide. Current methods to analyze urinary iodide are limited by complicated sample pretreatment, costly infrastructure, and/or poor selectivity, posing restrictions to large-scale epidemiological studies. We describe a simple yet selective method to analyze iodide in volume-restricted human urine specimens stored in biorepositories by capillary electrophoresis (CE) with UV detection. Excellent selectivity is achieved when using an acidic background electrolyte in conjunction with dynamic complexation via α-cyclodextrin in an unmodified fused-silica capillary under reversed polarity. Sample self-stacking is developed as a novel online sample preconcentration method to boost sensitivity with submicromolar detection limits for iodide (S/N ≈ 3, 0.06 μM) directly in urine. This assay also allows for simultaneous analysis of environmental iodide uptake inhibitors, including thiocyanate and nitrate. Rigorous method validation confirmed good linearity (R(2) = 0.9998), dynamic range (0.20 to 4.0 μM), accuracy (average recovery of 93% at three concentration levels) and precision for reliable iodide determination in pooled urine specimens over 29 days of analysis (RSD = 11%, n = 87).
authors.affiliation: Department of Chemistry and Chemical Biology, McMaster University , Hamilton, Ontario L8S 4M1, Canada.
authors.forename: Adriana Nori
authors.initials: AN
authors.lastname: de Macedo
authors.forename: Koon
authors.initials: K
authors.lastname: Teo
authors.forename: Andrew
authors.initials: A
authors.lastname: Mente
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: McQueen
authors.forename: Johannes
authors.initials: J
authors.lastname: Zeidler
authors.forename: Paul
authors.initials: P
authors.lastname: Poirier
authors.forename: Scott A
authors.initials: SA
authors.lastname: Lear
authors.forename: Andy
authors.initials: A
authors.lastname: Wielgosz
authors.forename: Philip
authors.initials: P
authors.lastname: Britz-McKibbin
mesh_terms: D019075:Electrophoresis, Capillary / Q000379:methods*; D006801:Humans; D007455:Iodine / Q000652:urine*; D015203:Reproducibility of Results
chemical_list: D007455:Iodine