AN AUTOMATED-SYSTEM FOR MULTICHANNEL FLOW-INJECTION ANALYSIS

An automated multi-channel flow-injection analyzer was developed both for new flow-injection analysis (FIA) procedures and for the process monitoring of animal and microbial cultivations. Up to six different analytes can be determined sequentially. The FIA set-up is working with up to six enzyme reactors configurated in parallel but with only one fluorescence detector and one pair of injection valves. By means of an automated sampling device the analyzer can be coupled on-line to a fermentation process. All active hardware components are computer controlled independently from each other guaranteeing a high flexibility. The software package, Flow Injection Analysis Control and Configuration (FIACCO), was developed for the hardware control, signal evaluation and long term recording of the on-line calculated results. Single and double step stopped flow procedures were developed to control the analyte conversion in packed bed enzyme reactors without an essential increase of the peak widths. Two carrier solutions are mixed to adjust the optimum pH for each applied enzyme also within one cycle of analysis. An enzymatic and a nonenzymatic procedure was developed to determine ammonia/ammonium after its gas dialytic separation from the sample solution. The application of the FIA set-up to the on-line process monitoring of an animal cell culture is demonstrated with respect to the five key components, glucose, ammonia, glutamine, glutamate and lactate.