The GX-274 ASPEC four-probe liquid handling instrument processes up to 4 samples in parallel. The system can be configured with dual syringe pumps. A four-probe Z-arm increases throughput. On-bed reservoirs allow access to up to four solvents without utilizing a position on the bed. Rinse station minimizes cross-contamination and sample-to-sample contamination, but is also available with two sets of transfer ports that provide access to two additional large volume solvent reservoirs without taking up any on-bed rack positions. Modular design allows the use of Code 200 or Code 34X series racks.