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Novel Electrochemical Assay for H 2 O 2 Determination in Aqueous Solutions: A Non Time‐Critical Method for H 2 O 2 Trace Level Detection
Author(s) -
GajovicEichelmann Nenad,
Bier Frank F.
Publication year - 2005
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.200403212
Subject(s) - chemistry , peroxidase , detection limit , chromatography , linear range , substrate (aquarium) , aqueous solution , fluorescence , trace amounts , enzyme , biochemistry , organic chemistry , medicine , oceanography , physics , alternative medicine , quantum mechanics , pathology , geology
Abstract A two‐step method for H 2 O 2 trace level determination has been developed, utilizing, for the first time, the fluorogenic peroxidase substrate, Amplex Red ( N ‐acetyl‐3,7‐dihydroxyphenoxazine), in conjunction with an electroanalytical detection scheme: Upon peroxidase catalyzed turnover of H 2 O 2 with Amplex Red, the fluorescent and electroactive product resorufin (7‐hydroxy‐3 H ‐phenoxazin‐3‐one) was detected amperometrically in a thin‐layer flow cell with high selectivity. A linear detection range from 100 nmol L −1 through 1000 nmol L −1 was obtained. The performance was validated using exhaled breath condensates (EBC) with and without H 2 O 2 added, as real samples. Due to the improved chemical stability of resorufin as compared to H 2 O 2 , processing larger numbers of EBC samples is greatly facilitated with the new assay, since the enzymatic reaction can be performed up to 18 hours before the actual measurement.