Automated fluorimetric method for hydrogen peroxide in atmospheric precipitation

TLDR: In this article, an automated analytical technique for the determination of hydrogen peroxide (H/sub 2/O/sub2/) in the liquid phase has been developed, which is based on the reaction of H /sub 2 /O/Sub 2 with horseradish peroxidase and p-hydroxyphenylacetic acid (POPHA).

Abstract: An automated analytical technique for the determination of hydrogen peroxide (H/sub 2/O/sub 2/) in the liquid phase has been developed. The chemistry of this technique is based on the reaction of H/sub 2/O/sub 2/ with horseradish peroxidase and p-hydroxyphenylacetic acid (POPHA). The resulting reaction forms the fluorescent dimer of POPHA. By use of conventional fluorescence detection techniques a detection limit of 1.2 x 10/sup -8/ M (0.4 ppbm) H/sup 2/O/sup 2/ is obtained for a 1.5-mL aqueous sample. The coefficient of variation is 0.66% at 1.6 x 10/sup -6/ M (53 ppbm). The analytical chemical reaction responds stoichiometrically to both H/sup 2/O/sup 2/ and organic hydroperioxides. To discriminate H/sup 2/O/sup 2/ from organic hydroperioxides, a novel dual-channel chemical flow system has been devised to separately determine total hydroperioxides and organic hydroperioxides. The concentration of H/sup 2/O/sup 2/ is determined by the difference between these two measurements. The system has been tested extensively for potential interferences commonly found in environmental aqueous samples, and none has been observed. 17 references, 4 figures, 2 tables.