Use of a siloxane polymer for the preparation of amperometric sensors: O-2and NO sensors and enzyme sensors

An amperometric oxygen transducer for the use of an oxidase-based sensor wa s prepared by coating the electrode surface from an emulsion of polydimethy lsiloxane (PDMS). The porous, hydrophobic PDMS layer prepared allowed the p ermeation of oxygen but restricted the passage of hydrogen peroxide, which made it possible to monitor the oxygen consumption through the oxidase-cata lyzed reaction without interference from the hydrogen peroxide produced thr ough the enzymatic reaction. An enzyme sensor for L-lactic acid (50 muM-0.6 mM) was fabricated by embedding a lipid-modified lactate oxidase in the PD MS layer, and used for the L-lactate determination in serum samples. The pe rmselective PDMS-layer was also applied to the preparation of an amperometr ic nitric oxide sensor. The concentration of nitric oxide (20 nM-50 muM) co uld be measured at 0.85 V versus Ag/AgCl without serious interference from oxidizable species such as L-ascorbic acid, uric acid and acetaminophen. (C ) 2001 Elsevier Science B.V. All rights reserved.