Evaluation of automated micro solid phase extraction tips (μ-SPE) for the validation of a LC-MS/MS bioanalytical method

Automated mu-SPE tips were successfully utilized for the determination of posaconazole in rat plasma. The bioanalytical method using mu-SPE tips was successfully qualified for routine quantitation of posaconazole over the concentration range of 10.0-10,000 ng/mL in rat EDTA plasma. Inter-assay precision. based on percent relative deviation for n = 18 replicate quality controls, was <= 5.7%. Inter-assay accuracy based on n = 18 replicate quality controls was +/- 7.7%. Complete solid phase extraction using mu L-SPE tips was demonstrated on a Tomtec liquid handler where > 95% recovery for posaconazole was obtained. The mu-SPE tips had sufficient capacity to extract at least 100 mu L plasma fortified with 10 mu g/mL of posaconazole and the analyte could be efficiently eluted with as little as 60 mu L of methanol. Of particular note is the unique ability of these mu-SPE tips to perform exhaustive solid phase extraction more commonly performed when using liquid/liquid extraction. (c) 2006 Elsevier B.V. All rights reserved.