Thirty-five mL of sample are extracted with 2 mL of hexane. Two UL of the extract are then injected into a gas chromatograph equipped with a Iiiearized electron capture detector for separation and analysis. Aqueous calibration standards are extracted and analyzed in an identical manner as the samples in order to compensate for possible extraction losses. The extraction and analysis time is 30 to 50 min per sample depending upon the analytical conditions chosen. Confirmatory evidence can be obtained using a dissimilar column. When component concentrations are sufficiently high, Method 524.1 or 524.2 may be employed for improved specificity.