Drugs of Abuse in Oral Fluids: Automated SPE Extraction and LC/MS/MS Determination using a Robotic Autosampler



Solid phase extraction (SPE) is one of the sample preparation methods most widely used by chromatographers, as can be seen from the large number of SPE methods found in the literature. Typically, a liquid sample is passed across an adsorbent bed to retain and concentrate target analytes and eliminate interference from the sample matrix. Alternatively, the adsorbent can be used to retain interferences while allowing the target analytes to pass through. Manual SPE cartridge formats can vary from disks to individual cartridges with various volumes of sorbent to 96-well plates. However, solid phase extraction can be tedious and time consuming when performed manually and there is increasing demand for automation of SPE methods. The MPS roboticpro is a  highly efficient LC or GC autosampler with extended robotic functionality. The MPS roboticpro provides reliable processing of complex tasks including automation of SPE procedures. Syringe holders and syringes are integrated in special syringe modules, which can be exchanged automatically within a running sequence for maximum flexibility. The system is controlled in a simple and efficient manner using the proven GERSTEL MAESTRO software. In this study, we show that an existing SPE method using ITSP cartridges [1] can be automated using the MPS roboticpro autosampler under MAESTRO control. An example of a solid phase extraction method illustrating the determination of drugs of abuse in oral fluid isshown.