ANALYTICAL PERFORMANCE TESTING OF AN ATRAZINE IMMUNOASSAY SYSTEM

A rigorous performance evaluation of an enzyme immunoassay (EIA) kit f or the determination of atrazine in water samples was undertaken, Elev en individual batches of samples containing standards and spiked drink ing waters were analysed and precision, bias and limit of detection we re measured using statistical analysis. The technique was shown to be capable of achieving performance criteria (a total standard deviation of less than 5% or 2.5 ng, whichever is the greater) demanded of moder n analytical systems and achieved a limit of detection of 9.2 ng l(-1) . There was no statistically significant bias measured for drinking wa ter samples, Interference tests showed that the atrazine immunoassay w as not significantly affected in the pH range 4.0-8.0 or by drinking w ater matrix components (anions, cations and chlorination by-products), even at their maximum allowable concentrations, There was a small ext ent of cross-reaction with simazine and atrazine degradation products, but given the persistence of atrazine; through its resistance to hydr olysis, breakdown products are likely to be present at much lower conc entrations than the parent compound in drinking mater, Simazine may po tentially be more problematic, so it mould be prudent to monitor a pro portion of samples for simazine to determine the extent to which this may be contributing to the 'atrazine' measured in drinking water sampl es using the EIA kit.