Abstract
Atrazine, simazine, 2, 4-D, silvex, and 2, 4, 5-T, were determined in natural water samples at 10 ppb levels by solid phase extraction on disposable C18 columns and TLC on preadsorbent silica gel layers impregnated with AgNO3, exposure to UV light, and densitometric scanning. Recoveries ranged from 70 to 88% for the triazines and 93 to 100% for chlorphenoxy acid herbicides, with average CV values of 7 to 8%. Solid phase extraction proved to be an advantageous alternative to classical liquid-liquid partition for the analysis of water for these compounds by quantitative TLC.