Insecticide fingerprinting technique for detection and location of organochlorine insecticide residues in foods.

Insecticide fingerprinting technique enables the detection and location of DDT and HCH residues in vegetables through the development of green and prussian blue colors respectively. Cut vegetables are pressed against o-tolidine impregnated paper and exposed to sunlight where colored spots appear instantly. The studies on 18 vegetable varieties revealed the pesticide residues and their distribution in different tissues. This direct method is sensitive (0.3/micrograms for HCH & 0.5/micrograms for DDT) and has special applications in quality control laboratories and food industry.