Photometric determination of dithiocarbamate residues by carbon disulphide evaluation method.

A review of analytical methods for determination of dithiocarbamate residues by carbon disulphide evaluation method was made. On basis of KEPPEL method the colorimetric step was modified. For this purpose the reaction of hydrogen sulphide with p-aminodimethylaniline in the presence of ferric and zinc ions to form methylene blue was applied. The coloured compound after a chloroform extraction was measured at 650 nm. The method gives a very high sensitivity of about 2 mug. Recoveries obtained with zineb and maneb for various crops are satisfactory.