Abstract
The addition of 1.5 ml water or 1.5 ml 0.1 N oxalic acid solution to 2 g soil samples containing 14C-labeled herbicides increased the 14C extraction efficiencies. The employment of a modified dioxane extracting-counting solution allowed the addition of 2 ml water without causing a liquid phase separation. Extraction of benzoic acid herbicides from soil was enhanced when 5 mg oxalic acid was added to 2 g soil or when soil was acidified to pH 4.1.