Selective and sensitive detection of nitrite based on NO sensing on a polymer-coated rotating disc electrode

A new effective way of nitrite detection in complex samples is presented. It is based on chemical conversion of nitrite to nitric monoxide (NO) in acidic aqueous solution containing hexacyanoferrate(II) as a reductor. NO is then detected on a poly-eugenol coated platinum electrode. When the electrode is rotating and the reduction medium is continuously purged with nitrogen, the addition of a nitrite-containing sample produces narrowed current spikes. The peak current is proportional to nitrite content in the sample over the range of 5.0-100 mu M and detection limit is 0.6 mu M. The method is simple and highly reproducible. Relative standard deviation of 10 repetitions is less than 4%. Practical utility of the proposed approach is demonstrated by nitrite determination in human saliva. (c) 2007 Elsevier B.V. All rights reserved.