A LABORATORY AND FIELD-EVALUATION OF A PORTABLE IMMUNOASSAY TEST FOR TRIAZINE HERBICIDES IN ENVIRONMENTAL WATER SAMPLES

The usefulness and sensitivity, of a portable immunoassay test for the semiquantitative field screening of water samples was evaluated by me ans of laboratory and field studies, Laboratory results indicated that the tests were useful for the determination of atrazine concentration s of 0.1 to 1.5 mug/L. At a concentration of 1 mug/L, the relative sta ndard deviation in the difference between the regression line and the actual result was about 40 percent. The immunoassay was less sensitive and produced similar errors for other triazine herbicides. After stan dardization, the test results were relatively insensitive to ionic con tent and variations in pH (range, 4 to 10), mildly sensitive to temper ature changes, and quite sensitive to the timing of the final incubati on step, variances in timing can be a significant source of error. Alm ost all of the immunoassays predicted a higher atrazine concentration in water samples when compared to results of gas chromatography. If th ese tests are used as a semiquantitative screening tool, this tendency for overprediction does not diminish the tests' usefulness. Generally , the tests seem to be a valuable method for screening water samples f or triazine herbicides.