[Analysis of dithiocarbamate pesticide residues a comparison of the head space and the colorimetric method (author's transl)].

The colorimetric method of Keppel [1] has been used. To be able to analyse 20 and more samples we slightly changed the head space method of McLeod [3]. To cutted lettuce which is brought into a penicilline flask, we add HCl and a reducing agent (SnCl2), and close the flask. After overnight heating on a waterbath the liberated CS2 is injected into a gaschromatograph with a flame photometric detector. The results are compared with known quantities of zineb, added to lettuces. A correlation factor r = 0.9903 has been found.