Analysis of herbicides: demonstration of the utility of enzyme immunoassay verification by HPLC.
Evidence has accumulated that herbicides in the environment present a significant health hazard to the population. Therefore, the levels of heavily used substances such as atrazine and simazine and their metabolites need to be regularly assessed. The objective was to develop a rapid and simple tube ELISA procedure suitable for use in field studies and non-specialized laboratories. The antisera used were polyclonal antibodies raised in sheep against atrazine or simazine amido caproic acid conjugated to bovine serum albumin. The antibodies were first used to construct a two-step competitive ELISA procedure in 96-well microtitre plates. The 96-well format was then adapted to a coated-tube enzyme immunoassay, by immobilization of hapten-gelatine conjugates on polystyrene tubes. This enabled the colour to be read using a basic spectrophotometer. Soil samples were collected from agricultural and non-agricultural sites in Poland. Atrazine and simazine were extracted by liquid extraction from soil and assayed by tube ELISA. In addition, the samples were extracted by solid-phase extraction before analysis by HPLC. The immunoassays and chemical analysis were carried out by different individuals who were unaware of each other's results, which were then compared at the end of the study. Correlation of the two methods was excellent, with R=98.7 and 81.3 for atrazine and simazine, respectively. The immunoassay yielded the same order of results without having to perform solid-phase extraction before analysis. The study has demonstrated that the simple antigen-coated tube assay provides a cost-effective and valuable screening test. Comparison with the more elaborate, heavily labour-intensive HPLC analysis demonstrated that the results obtained by the simpler enzyme-immunoassay tests were within the same order.
Price
R G
RG
School of Biomedical and Health Sciences, Analytical Research Group, Pharmaceutical Science Division, King's College London, University of London, UK. robert.price@kcl.ac.uk
Baranowska
I
I
Griffith
H M T
HM
Abuknesha
R A
RA
Barchanska
H
H
D001280:Atrazine / Q000737:chemistry; D015415:Biomarkers / Q000032:analysis* / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004305:Dose-Response Relationship, Drug; D006241:Haptens / Q000737:chemistry; D006540:Herbicides / Q000032:analysis* / Q000494:pharmacology*; D007124:Immunoenzyme Techniques / Q000379:methods*; D011137:Polystyrenes / Q000737:chemistry; D015203:Reproducibility of Results; D012839:Simazine / Q000737:chemistry; D012987:Soil; D013053:Spectrophotometry / Q000379:methods
D015415:Biomarkers; D006241:Haptens; D006540:Herbicides; D011137:Polystyrenes; D012987:Soil; D001280:Atrazine; D012839:Simazine