STUDY OF LOT-TO-LOT REPRODUCIBILITIES OF BOND ELUT CERTIFY AND CLEAN SCREEN DAU MIXED-MODE SOLID-PHASE EXTRACTION COLUMNS IN THE EXTRACTIONOF DRUGS FROM WHOLE-BLOOD

The lot-to-lot reproducibilities of Bond Elut Certify and Clean Screen DAU columns are described. The recoveries of five test drugs obtained from twelve lots of Bond Elut Certify columns ranged from 84 to 104% with standard deviations of less than 9%. The recoveries of five test drugs obtained from six lots of Clean Screen DAU columns ranged from 8 1 to 103% with standard deviations of less than 7%. The 95% confidence intervals of the means as obtained by ANOVA demonstrate that there ar e no significant differences between the tested lots of Bond Elut Cert ify and Clean Screen DAU columns. Comparison of the two brands shows t hat both Bond Elut Certify and Clean Screen DAU columns are well accep table for routine drug screening in systematic toxicological analysis, with a slightly higher overall recovery for the former.