A METHOD FOR THE DETERMINATION OF RHODAMINE-B AND BRILLIANT SULFAFLAVINE ON COTTON STRING COLLECTORS AND IN A SPRAY TANK SOLUTION MIXTURE

A fluorescent method for the determination of rhodamine B (RhB) and br illiant sulfaflavine (BSF) dual tracers on cotton string collectors an d in spray tank solutions was developed for the evaluation of the effe cts of adjuvants on the atmospheric drift of agricultural sprays. Both tracers on collectors were extracted with deionized water simultaneou sly and measured directly with a Fluorescent Specrometer by switching the maximum excitation and emission wavelengths. The linear ranges of the RhB and BSF standard curves were 0 similar to 50 and 0 similar to 10 ppb respectively. Recoveries of tracers on cotton strings ranged fr om 92.9% +/- 1.1% to 95.1% +/- 1.0% for RhB and 91.9% +/- 2.8% to 103% +/- 0.6% for BSF when spiked levels ranged from 0.25 to 2.5 mu g per collector. The detection limit of the instrument was approximately 0.1 ppb for both tracers. The detection limits of the analytical method w ere approximately 0.1 ppb for RhB and 0.3 ppb for BSF when the backgro und levels of cotton strings were subtracted. The presence of one trac er in the solution did not significantly interfere with the detection of the other tracer in the same solution. The presence of adjuvants ad ded to the spray tank solutions did not interfere with the detection o f both tracers when the adjuvants were applied at the manufacturer's m aximum recommendation rates.