Micro Extraction by Packed Sorbent (MEPS) is a new method of sample preparation that performs the same function as SPE, but works with much smaller sample volumes than full-scale SPE, can be fully automated, and uses the same syringe for sample processing, extraction, and injection steps performed on-line. The MEPS system consists of a MEPS syringe and the MEPS Barrel Insert and Needle Assembly (BIN). The BIN contains the SPE phase, and is built into the syringe needle. When the BIN is exhausted, or another phase is required, the BIN is easily removed and replaced.

Sample volumes as small as 10µL can be used, or larger samples can be concentrated by taking multiple aliquots of 100 or 250µL

MEPS procedures are suitable for reversed phases, normal phases, mixed mode, and ion exchange chemistries. Syringes may be used manually. No mount modifications are required when used with Thermo Scientific and CTC Analytics auto-injectors.

The ability to prepare and inject samples on-line using a single device reduces processing time and the need for operator intervention. Typical BIN lifespan is 40–100 samples, depending on the sample matrix. The small quantity of phase in the MEPS BIN can be washed between samples to eliminate the possibility of carry-over. BINs are available in a variety of common SPE phases. Dimensions of the sorbent bed ensure that the sorbent performance remains identical to conventional SPE devices used for extraction of similar samples. Sample preparation for complex biological samples can be adapted to MEPS.