title: Direct colorimetric method for determination of organophosphates in human urine.
abstract: A simple and sensitive method for determination of organophosphorus pesticides in human urine was developed by detecting the color complexes which resulted from reactions of organophosphorus pesticides and 4-(4-nitrobenzyl)pyridine (NBP) in urine. Based on studies of reaction conditions, e.g. reaction temperature and time, and reagent concentration, a colorimetric method was established. A 0.1-ml volume of NBP (45% in acetone) was added to a 1.0-ml volume of a urine sample, and the mixture was heated at 100 degrees C for 20 min. After cooling, 0.1 ml of tetraethylenepentamine was added. The organophosphorus pesticides showed a characteristic purplish blue color and the coloring complexes which were produced were stable for several hours. Furthermore, these complexes could be determined spectrophotometrically. The detection limits were 0.10-10 microg/ml in urine. The required time for analysis was approximately 30 min for one sample. Comparing the result of the proposed method with those of the GC-MS method, the results were similar for the 12 poisoning cases studied. Thus, the proposed method is useful for detection of these pesticides in critical care practices.
authors.affiliation: Department of Legal Medicine, Hiroshima University School of Medicine, Kasumi 1-2-3, Minami-Ku, Hiroshima, Japan. namera@ipc.hiroshima-u.ac.jp
authors.forename: A
authors.initials: A
authors.lastname: Namera
authors.forename: Y
authors.initials: Y
authors.lastname: Utsumi
authors.forename: M
authors.initials: M
authors.lastname: Yashiki
authors.forename: M
authors.initials: M
authors.lastname: Ohtani
authors.forename: T
authors.initials: T
authors.lastname: Imamura
authors.forename: T
authors.initials: T
authors.lastname: Kojima
mesh_terms: D002614:Chelating Agents; D002863:Chromogenic Compounds; D003124:Colorimetry / Q000379:methods*; D005029:Ethylenediamines; D008401:Gas Chromatography-Mass Spectrometry; D006358:Hot Temperature; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007306:Insecticides / Q000506:poisoning / Q000652:urine*; D009943:Organophosphorus Compounds; D011725:Pyridines; D012680:Sensitivity and Specificity; D013053:Spectrophotometry
chemical_list: D002614:Chelating Agents; D002863:Chromogenic Compounds; D005029:Ethylenediamines; D007306:Insecticides; D009943:Organophosphorus Compounds; D011725:Pyridines; C008633:4-(4-nitrobenzyl)pyridine; C034269:tetraethylenepentamine