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Research points out that the amount of highly reactive gamma-keto aldehydes, neuroketalsprotein adducts, mediating the brain disorders due to oxidative stress, are underestimated if only unoxidized neuroketal adducts are measured since a significant portion of neuroketals undergo oxidaion in vivo.

We describe the preparation, characterization, and performance of an aldehyde biosensor based on the determination of NADH generated by the enzymatic activity of immobilized (on a nylon mesh membrane) aldehyde dehydrogenase. The enzymatically generated NADH is, in turn, electrocatalytically oxidized at a glassy carbon electrode modified with an electropolymerized film of 3,4-dihydroxybenzaldehyde (3,4-DHB). We have characterized the response of the biosensor in terms of the effects of the immobilization procedure, enzyme loading, pH of the solution, and the presence of anionic species with particular emphasis on the role of phosphate anions. In addition, we have carried out studies of the kinetics of the catalytic reaction, as well as permeability studies. The sensor exhibits high sensitivity and a limit of detection in the micromolar regime (5.0 [[micro]molar]), as well as rapid response (60 s to reach 90% of its steady state value). We have also carried out analytical determinations of aliphatic and aromatic aldehydes and consistently find that aromatic aldehydes give superior results.

Ozone oxidation and water vapor hydrolysis can interfere with the effective measurement of atmospheric aldehydes and ketones using the dansylhydrazine (DNSH) and 2,4-dinitrophenylhydrazine techniques. The potential interferences to a newly-developed, highly sensitive DNSH microcartridge technique is investigated with the use of silanized glass beads and octadecylsilane particles as reagent supports. Results indicate that water vapor seriously interferes in the DNSH technique and that ozone provides no significant interference in the technique.