This profile can be used for food, vegetation, soil or water samples. Included in this profile are the common chlorophenoxy acid herbicides. The half-life in soil of most of these compounds is relatively short, on the order of 30 days or less. However, several of them (e.g., clopyralid, triclopyr, fluroxypyr and picloram) can survive in soil much longer. Most are commonly sold as water soluble salts, which are ionic in nature. Ester forms, which are generally oil (or emulsion) based, will hydrolyze rapidly under field conditions to the free acid form which is ionic. We report results for these herbicides as the free acid equivalent.