This On-Line Autosampler, used in conjunction with Nova Biomedical BioProfile Chemistry Analyzers, can withstand multiple steam sterilization cycles. The unit incorporates stainless steel fittings and PharMed tubing, as well as modified versions of its cleaning and sampling valves and an improved sterile barrier manifold. Multiple bioreactors can be connected directly to an analyzer for unattended sampling. The autosampler establishes user-defined sampling frequencies and feedback instructions for each reactor vessel when preset limits are reached. All results are stored on-board, and can be retrieved individually or in the form of a trend analysis or user report. Featuring touch-screen operation, the unit can manage up to four bioreactors and eight feedback control systems while maintaining bioreactor sterility.