title: Practical immunochemical method for determination of 3,5, 6-trichloro-2-pyridinol in human urine: applications and considerations for exposure assessment.
abstract: An analytical method is described for the quantitative determination of 3,5,6-trichloro-2-pyridinol (3,5,6-TCP) in human urine. This is the primary analyte found in urine as a result of exposure to chlorpyrifos, chlorpyrifos-methyl, triclopyr, or 3,5,6-TCP. Conjugates of 3,5,6-TCP are released from urine by acid hydrolysis. The free 3,5,6-TCP is purified using C(18) solid-phase extraction, eluting the analyte with 1-chlorobutane. An aliquot of 1-chlorobutane is placed in a vial containing Trichloropyridinol Sample Diluent and evaporated, leaving the 3,5,6-TCP in the aqueous sample diluent. The samples are assayed using the Trichloropyridinol RaPID Assay immunoassay test kit. Final results are calculated using a standard curve constructed by linear regression after a ln/Logit data transformation is performed of the concentration and the absorbance readings, respectively. The calculated lower limit of quantitation for 3,5,6-TCP in fortified control urine samples is 2. 96 ng/mL (2.96 ppb). Residues of 3,5,6-TCP determined using both immunochemical and gas chromatography with mass spectrometric detection correlate well.
authors.affiliation: Global Environmental Chemistry Laboratories-Indianapolis Laboratory, Dow AgroSciences LLC, 9330 Zionsville Road, Indianapolis, Indiana 46268-1054, USA. ddshackelford@dowagro.com
authors.forename: D D
authors.initials: DD
authors.lastname: Shackelford
authors.forename: D L
authors.initials: DL
authors.lastname: Young
authors.forename: C A
authors.initials: CA
authors.lastname: Mihaliak
authors.forename: B A
authors.initials: BA
authors.lastname: Shurdut
authors.forename: J A
authors.initials: JA
authors.lastname: Itak
mesh_terms: D004781:Environmental Exposure; D008401:Gas Chromatography-Mass Spectrometry; D006540:Herbicides / Q000652:urine*; D006801:Humans; D011728:Pyridones / Q000652:urine*; D011786:Quality Control; D012680:Sensitivity and Specificity
chemical_list: D006540:Herbicides; D011728:Pyridones; C012587:3,5,6-trichloro-2-pyridinol