A continuous flow system combined with a sensing fluorimetric transductor for the determination of β-naphthol

• Published in: Microchemical journal 2002-12, Vol.73 (3), p.279-285
• Main Authors: Algar, S.Ortega, Martos, N.Ramos, Dı́az, A.Molina
• Format: Article
• Language: English
• Subjects: Analysis methods; Analytical chemistry; Applied sciences; Chemistry; Environmental analysis; Exact sciences and technology; Flow-injection analysis; Flow-through sensor; General, instrumentation; Natural water pollution; Pollution; Spectrofluorimetry; Water treatment and pollution; β-Naphthol
• ISSN: 0026-265X; 1095-9149
• DOI: 10.1016/S0026-265X(02)00095-4

A single automatic method for continuous flow determination of β-naphthol based on the enhancement of its native fluorescence once the analyte was transitorily retained on-line on a solid support (QAE A-25 resin) is reported. So, a flow-through optosensor was developed using a flow-injection analysis system with solid phase fluorimetric transduction. KCl (0.15 mol l −1) at pH 12.0 was used as carrier solution. To obtain the optimum fluorescence signal the wavelengths chosen were 245 nm (excitation) and 420 nm (emission). The response of the sensor was directly proportional to the sample volume injected in the studied range 40–1500 μl. Approximately one higher order of magnitude is achieved in sensitivity when 1500 μl are used with respect to the use of 40 μl of sample. The sensor was calibrated for three different injection volumes: 40, 600 and 1500 μl, responding linearly in the measuring range of 2–60, 0.5–15 and 0.2–5 μg l −1 with detection limits of 0.5, 0.09 and 0.05 μg l −1, respectively. The relative standard deviation for ten independent determination is 0.6% (40 μl), 0.9% (600 μl) and 2.3% (1500 μl). A recovery study was performed onto three different spiked water samples at concentration levels from 1 to 2.5 μg l −1 and the recovery percentage from the experimental data ranged between 101±2 and 105±5.