GENERAL SAMPLING SYSTEM FOR STERILE MONITORING OF BIOLOGICAL PROCESSES

A general sampling system was developed based on the use of a coaxial catheter consisting of two concentrically arranged catheters with the inner one a few millimetres shorter than the other. The sample is sucked through the inner lumen of the catheter. An inhibitor is added just at the tip of the catheter, causing the metabolic processes to terminate instantaneously and the sample remains unchanged until it reaches the measuring site. This arrangement means that the inhibitor is actually added to the sampling stream within the bioreactor. In spite of this, negligible leakage of inhibitor was detected over a period of 6 days. Examples of measurements of samples from patients and from fermentations are given.