Abstract: The method was based on formation of the dithiocarbmate ion - Cu(II) complex which was extracted into isobutyl methyl ketone (I) in a flow injection system and determined by AAS. An aqueous solution (25 ml) containing the sample, e.g., diethyldithiocarbamate (II), 2.0 mL of 10 mM Cu(II) and 15 mL of 0.5 M acetic acid - acetate buffer (pH 4.7) was mixed in a segmenter with a I stream (1.0 mL min-1) and passed through a 25-cm long extraction coil and a membrane phase separator (described). An aliquot (40 µL) of the separated I solution was injected into a water stream (2.25 mL min-1) in which the Cu was determined by AAS in an air - acetylene flame at 324.7 nm. The possibility of interference from other metals and dithiocarbamates in the determination of II was discussed. The method was used to determine 6.0 to 12 µM-II; the detection limit was 0.12 µM-II. In the determination of 8.0 µM-II the precision was 2.6% (n = 10). The method was applied to determining 3.2 to 8.0 µM-ziram (procedure described).