Reverse flow injection spectrophotometric determination of Thiram and Nabam fungicides in natural water samples

A reverse flow injection (rfi) spectrophotometric method is reported for determination of thiram and nabam fungicides in natural water samples. the method is based on the reduction of iron(iii) in the presence of thiram/nabam in acidic medium at 60oc and formation of iron(ii)- ferricyanide complex was measured at 790 nm. the limits of detection (3s blank) were 0.01 and 0.05 μg ml-1 for thiram and nabam respectively with a sample throughput of 60 h-1. calibration graphs were linear over the range of 0.02 - 8.0 μg ml-1 (r2 = 0.9999,n = 8) and 0.1 - 30 μg ml-1 (r2 = 0.9982,n = 10) for thiram and nabam with relative standard deviations (rsds; n = 3) in the range of 0.8 - 1.6% respectively. experimental parameters and potential interferences were examined. thiram and nabam were determined in natural water samples using solid-phase extraction (spe) procedure and recoveries were in the range of 93±3 - 105±2% and 87±4 - 102±3% respectively. the results obtained were not significantly different compared with a hplc method.