Infrared thermal imaging combined with paper microzone plates and natural reagent extracts for simple, fast, and green enthalpimetric analysis

Paper microzone plates and thermal infrared enthalpimetry (TIE) were combined with potato juice as natural reagent extract to perform the determination of hydrogen peroxide in pharmaceutical, bleaching, and toiletry products. A multichannel pipette was used for reagent addition simultaneously in multiple zones of paper devices, and the temperature rise was determined using an infrared camera. In order to provide suitable measurements, some parameters were optimized such as pH, volume of reagents, and stability of the extract. Results for the hydrogen peroxide were compared with those obtained using methods from official compendia (United States Pharmacopeia and ASTM D2180–17), with agreements ranging from 96 to 103%. The green analytical procedure index was used to compare the greenness of the proposed method with official ones, with clear advantages for TIE. Only microliters of samples and natural reagent extracts were required for analysis, and it was found that waste generation could be greatly reduced. After analysis, the paper device could be directly disposed since the final products of the reaction were O2 and water. According to these features, the proposed method could be considered a promising alternative to routine analysis in agreement with green analytical chemistry principles. [Display omitted] •New sensing approach for paper devices is proposed using infrared thermal imaging.•Paper microzone plates were used to perform green enthalpimetric analysis.•Potato juice was used directly as a natural reagent extract.•Drastic reduction of waste generation, energy and time consumption was reached.•Green analytical chemistry metrics was used for comparison with official methods.