MicroLiter offers an Instrument Top Sample Prep (ITSP) system that uses autosampler-based solid phase extraction to replace labor intensive manual methods for forensic drug testing. The ITSP system attaches to LC and GC instruments and allows serial solid phase extractions to be performed within the run time of the instrument, increasing productivity and reducing costs. It is well-suited for urine-based drug testing for cocaine, opiates, and THC using LC/MS/MS. Existing autosamplers can be retrofitted with the ITSP system for about $2000.