Equipment to automate extraction procedures has been available for well over 20 years. In fact, many bioanalytical laboratories still run some extractions manually, and in most laboratories a semiautomated approach is adopted. Two reasons in particular may account for this. First, the most widely used sample preparation methods of solid-phase extraction (SPE) and protein precipitation (PP) are already quite efcient procedures and may actually take less of an analyst’s time than is rst thought. Second, although the total number of samples analysed by many laboratories is large, the number for any single study varies from less than 100 to perhaps 1500 samples, leading to the requirement of frequently setting up and then changing from one method to the next. The additional overhead of establishing automated assays, and, in the past, the additional reliability problems caused by the automated instruments themselves, have made the overall benet of automation seem equivocal for many laboratories.