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- Title
Sequential injection multi-optosensor based on a dual-luminescence system using two sensing zones: application to multivitamin determination.
- Authors
Llorent-Martínez, Eulogio J.; Ortega-Barrales, Pilar; Molina-Díaz, Antonio
- Abstract
The coupling of sequential injection analysis (SIA) and solid-phase spectroscopy (SPS) with luminescence detection is carried out with a novel characteristic: the use of two different detection techniques in the same system, therefore enhancing the scope of applications. This approach allows the determination of compounds with dissimilar spectroscopic characteristics. By means of a SIA multivalve, the sample can be easily pumped towards the detector, therefore allowing the use of the double-detection technique. The determination of vitamins B2, B6 and C is presented. Taking into account the native fluorescence of B6 and B2, these analytes are determined by means of a spectrofluorimeter. However, as vitamin C does not display native fluorescence, its reaction with permanganate in a sulphuric acid medium is performed and the obtained chemiluminescence is the analytical signal measured. In every case, the determination is based on the direct measurement of the analytical signal of the respective vitamin retained on the sensing solid support placed on the respective detection area. Two different solid supports are used, a non-ionic C18 silica gel for the fluorescent compounds, and an anionic QAE-A25 for vitamin C. Detection limits of 0.12, 0.008 and 9.1 µg mL−1 for vitamins B6, B2 and C were obtained. The RSD was lower than 5% in all cases. The double-sensor was applied to the determination of the analytes in pharmaceuticals from the Spanish Pharmacopoeia, with a sample frequency up to 8 samples per hour.
- Subjects
SEQUENTIAL injection analysis; SPECTRUM analysis; VITAMINS; PERMANGANATES; SULFURIC acid; CHEMILUMINESCENCE; NONIONIC contrast media; ADDITION polymerization
- Publication
Microchimica Acta, 2008, Vol 162, Issue 1/2, p199
- ISSN
0026-3672
- Publication type
Article
- DOI
10.1007/s00604-007-0861-5