Supplying analytical devices with photogenerated in situ hydrogen peroxide

Paper-based analytical devices, lateral flow tests, dipsticks and other capillary flow-driven microfluidics usually contain reagents required for an assay preadsorbed in a porous support such as paper, glass microfiber or nitrocellulose. The reagents are stored in a dried form until rehydrated with the introduced sample. This allows limiting user-related steps and related with them issues. However, this approach is highly ineffective for hydrogen peroxide, a key reagent in various assays. To date, most devices require the addition of precise amount of H 2 O 2 solution by the user, which is troublesome and may be a source of errors. To obviate these difficulties, here we propose to employ in situ generation of this reagent. Flavin-catalyzed photochemical cycle was used to reduce O 2 to H 2 O 2 therefore supplying sensing devices with H 2 O 2 . Factors affecting H 2 O 2 photogeneration efficiency on paper were studied to establish this method's capabilities. The maximum amount of photogenerated H 2 O 2 is equivalent to the addition of 4 mmol L −1 of H 2 O 2 solution. Reagents immobilized on paper retain the ability to generate H 2 O 2 during at least 50 days of storage in the dark. Finally, the proposed H 2 O 2 photogeneration method was integrated into a simple proof-of-concept paper-based sensor for horseradish peroxidase inhibitor determination. Findings presented in this paper contribute to simplification of H 2 O 2 requiring assays conducted in point-of-need format and possibly extending the shelf-life of many sensing devices which utilize H 2 O 2 . • A novel method to supply analytical devices with H 2 O 2 is described. • This method relies on O 2 photoreduction by the means of flavins. • Reagents for photogeneration are stable immobilized on paper for at least 50 days. • Photogenerated H 2 O 2 was used as a substrate for HRP inhibition assay.