Reusability of Bond Elut Certify columns for the extraction of drugs from plasma.

The reusability of Bond Elut Certify columns for the extraction of toxicologically relevant drugs from plasma has been evaluated. Pentobarbital, hexobarbital, mepivacaine, trimipramine and clonazepam were selected as test drugs to represent various classes of drugs. The columns were regenerated immediately after an extraction by washing with methanol, hydrochloric acid (1%), water and methanol, sequentially. These regenerated columns were found to be reusable for plasma. More than 85% of the test drugs were recovered when the columns were used three times. However, the extraction power of the regenerated columns decreased slightly with the number of reuses, so that a column should not be used more than two or three times.