Using Bond Elut Certify columns, drugs were eluted into two groups (acidics or neutrals and basics), according to their physical properties, and analyzed by gas chromatography. Citrated calf plasma or urine, which had been spiked with the appropriate drugs, was diluted with phosphate buffer and vortexed to ensure homogeneity. The concentration of 10 micrograms/mL was chosen for analytical convenience as well as to represent toxicologically relevant levels for most of the drugs. After the plasma had been diluted with phosphate buffer (pH 6.0), the drugs were extracted using a single Bond Elut Certify column. The acidic and most of the neutral drugs were eluted by acetone/chloroform (1:1), and the basic drugs were eluted by 2 percent ammoniated ethyl acetate. Some neutral drugs appeared in both fractions. The fractions were analyzed separately on a gas chromatograph equipped with a wide-bore capillary column and a flame ionization detector. Clear extracts were obtained as well as excellent recoveries. 19 references, 3 tables, and 7 figures (Author abstract modified)