| Popis: |
A flow-injection procedure for the rapid determination of propane-1,2-diol and propylene oxide in aqueous solutions was developed. Propane-1,2-diol can be assayed with immobilized glycerol dehydrogenase and fluorimetric detection of the NADH generated. From 0.05 to 2.5 mM propane-1,2-diol can be determined with a sampling frequency of 40–50 h −1 and a precision of better than 98%. The determination range can be extended up to 50 mmol l −1 by means of a miniaturized dialysis cell. Higher molecular weight polypropylene oxides remain in the donor sample stream. Before its enzymatic determination, propylene oxide must be hydrolysed to propane-1,2-diol. Propylene oxide is selectively separated from propane-1,2-diol by a membrane gas diffusion step into a strong acid acceptor solution. After conditioning to pH 8.5 the quantatively generated propane-1,2-diol can be assayed enzymatically. An automatically controlled flow-injection set-up gave the possibility of the simultaneous determination of propylene oxide and propane-1,2-diol. |
