Analytical Sciences

Abstract − Analytical Sciences, 27(8), 827 (2011).

Automatic Multi-pumping Flow System for the Chemiluminometric Screening of Scavenging Capacity against Singlet Oxygen
Ana F. T. SILVA, Karine L. MARQUES, João L. M. SANTOS, and José L. F. C. LIMA
REQUIMTE, Departamento de Química, Faculdade de Farmácia, Universidade do Porto, Rua Aníbal Cunha, 164, 4099-030, Porto, Portugal
An automated multi-pumping flow system was developed for the in-line generation of singlet oxygen (1O2) and subsequent assessment of the scavenging capacity against this reactive species. 1O2 was generated by dismutation of hydrogen peroxide catalyzed by molybdate ions. The evaluation of the scavenging capacity was based on the inhibition of the chemiluminescence reaction of luminol with 1O2. The proposed system used solenoid micro-pumps as the only active components of the flow manifold, enabling the reproducible insertion and efficient mixing of sample and reagents as well as the transportation of the sample zone towards detection for chemiluminescence measurement, assuring a strictly reproducible timing of all analytical tasks. Several compounds were evaluated as possible 1O2 scavengers. The obtained results showed that only ascorbic acid, dipyrone and tryptophan exhibited scavenging capacity, with IC50 values of 3.36 × 10−5, 7.84 × 10−5 and 1.28 × 10−2 mol L−1, respectively.