Feature-rich and incorporating an integrated column oven, the Model 542 is a cost-effective autosampler for HPLC analysis. This compact-sized unit offers many features found in other more expensive autosamplers. It incorporates three selectable injection modes: full loop, partial loopfill, and microliter pick-up. Sample processing capabilities are provided for sample mixing, dilution, and on-line derivatization. The integrated column oven provides temperature control up to 60 °C and keeps injector to column tubing connection length to a minimum. The fluidic pathway uses biocompatible (PEEK) components. The quick-change injection valve simplifies change-over and minimizes down time. The standard sample tray capacity is 84 vials that are 1.8 mL in volume and 3 vials with 10 mL volume that are in positions for wash and alternate reagents. The sample tray can be cooled (refrigerated) by the addition of optional factory-installed temperature-control capability. Features include: quick-release bio-compatible injection valve, integrated column oven, integrated sample tray cooling (optional), injection system providing zero sample loss with limited sample volumes, optional sample tray formats, sample dilution, mixing and derivatization capabilities.