Improvement in the determination of mancozeb residues by the carbon disulfide evolution method using flow injection analysis

The sample decomposition of the can;bon disulfide evolution method for the determination of dithiocarbamate residues was carried out in a closed vial in the presence of hexane. The evolved carbon disulfide was extracted by th e organic solvent and injected in a now system for its quantification as co pper complex. The conditions for batch decomposition, flow injection determ ination, and association of both were investigated with sodium diethyldithi ocarbamate as model substance. An one-channel flow system was employed wher e the carrier stream was the ethanolic ethylenediamine/copper solution. The determination range was of 0.01-1.26 mu g of CS2, with a relative standard deviation of 0.06% (n = 10), with a sample throughput of 45 samples/h. The association of the batch decomposition with the flow system was carried ou t with the fungicide mancozeb and was applied to the analysis of its residu e in potato, lettuce, cucumber, and green bean crops. The approach allowed the analysis of 11 samples in triplicate in 2 h, with recoveries between 85 % and 92% and relative standard deviation about 2%.