Study of the enhanced chemiluminescence from the luminol-horseradish peroxidase-hydrogen peroxide-p-coumaric acid system at very short times: stopped flow selective determination of p-coumaric acid in beers
✍ Scribed by F.García Sánchez; A.Navas Díaz; J.A.González García
- Publisher
- Elsevier Science
- Year
- 1995
- Tongue
- English
- Weight
- 649 KB
- Volume
- 310
- Category
- Article
- ISSN
- 0003-2670
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✦ Synopsis
p-Coumaric acid has a greater enhancing effect on the chemiluminescence of the luminol-H,O,-horseradish peroxidase system, at low concentration, than other phenolic acids studied. We have used this effect to study the variations of the chemiluminescent signal with luminol, hydrogen peroxide, p-coumaric acid, horseradish peroxidase concentrations and pH, using the stopped-flow technique, by monitoring the initial reaction rate. The interference effects of other phenolic acids on the enhanced chemiluminescence with p-coumaric acid (25 nM) were negligible at similar concentrations of phenolic acid. We monitored the chemiluminescence intensity at 10 s for the determination of p-coumaric acid in beers. The detection limit was ca. 0.7 nM and the linear range was O-12.5 nM. The precision of the method, expressed as a relative standard deviation, was 2.5%.