Development of a general screening method for acidic, neutral, and basic drugs from whole blood using the Oasis HLB columns and the Oasis MCX columns

Abstract

Solid-phase extraction (SPE) is becoming a commonly used extraction technique. However, most of the existing solid-phase extraction methods extract a single drug from a relatively clean biological matrix (e.g. plasma or urine) using a silica based column. These methods are generally not satisfactory for forensic applications since the majority of biological samples are not clean (e.g. whole blood, bile, tissues) and the presence of drug is unknown. Silica based columns also have reproducibility and stability problems (i.e. irreproducible recoveries, sorbent instability at pH extremes). In this study, sequential extraction of acidic, neutral, and basic drugs from whole blood using the Oasis HLB(R) (Waters Corporation) and the Oasis MCX(R) (Waters Corporation) columns was attempted. Both columns are polymer based and are designed to overcome the limitations of silica based columns. Conditions for each step of the extraction sequence were optimized for a single drug or selected group of drugs then applied to a larger group of drugs consisting of the most commonly detected drugs in Manitoba forensic casework. (Abstract shortened by UMI.)