A multi-fiber handling device for in vivo solid phase microextraction–liquid chromatography–mass spectrometry applications

Solid phase microextraction, an in vivo and ex vivo sample preparation method, continues to capture growing interest among researchers for bioanalytical applications. When coupled with liquid chromatography mass spectrometry, the procedure often involves large numbers of fibers in, for example, both pharmacokinetic and pharmadynamic studies as well as other bioapplications. In this regard, appropriate and adequate precaution will be critical in preventing the fibers firstly from any possible external contamination and damage to maintain high analytical data integrity. In addition, improving the offline desorption of fibers specifically for in vivo SPME will not only help in improving data quality, but will also significantly decrease the overall analysis time. This article introduces a prototype multi-fiber handling device capable of simultaneous extraction/desorption of multiple solid phase microextraction (SPME) fibers on a 96-deep well plate format. This device thus provides an alternative approach to improving higher sample throughput for in vivo SPME liquid chromatography mass spectrometry applications. The portable design of the device ensures effective protection and prevention of fibers against damage and possible contamination and thus maintains analytical data reliability. To ensure its suitability for parallel extraction/desorption, the device was carefully evaluated using four benzodiazepines (diazepam, nordiazepam, oxazepam and lorazepam) as model drugs by monitoring inter- and intra-well variability. The effect of agitation speed on data precision and accuracy, effect of device weight on data precision, and comparison of the overall performance of the device with traditional manual desorption approach were also assessed. Results obtained from evaluation of the device with particular focus on the desorption process indicated that the weight of the device has no effect on the reliability and reproducibility of data acquired using the device. The average amount of diazepam obtained for 20 selected wells with and without device was 48.8 pg and 49.4 pg, respectively. Intra-, inter-well, and inter fiber variations recorded were all ≤13% indicating an excellent precision and reproducibility can be attained with the device.