Verfahren und Vorrichtung zur Bestimmung der Formaldehydkonzentration in waessrigen Medien

The invention relates to a process and a device for determining the formaldehyde concentration in aqueous media. This is obtained by immobilizing microorganisms which form products from formaldehyde in aqueous media, said products causing a pH change on the pH-sensitive surface of a pH measuring sensor by enclosing the microorganisms between the sensor surface and a water-insoluble, semi-permeable diaphragm. The immobilized microorganisms and the pH measuring sensor are contacted with definite quantities of aqueous measuring media of known formaldehyde concentrations, and the pH changes caused in a definite time interval are detected as measuring signals. The immobilized microorganisms are contacted with a defined quantity of the aqueous medium of known formaldehyde concentration under examination, and the ph change caused within a definite time interval is detected as a measuring signal. The formaldehyde concentration of the aqueous medium under examination is determined by comparing the measuring signal with the measuring signals of the measuring media