Chemiluminescence flow sensor for folic acid with immobilized reagents

A novel chemiluminescence (CL) sensor for folic acid combined flow-injectio n (FI) technology was presented in this paper. The analytical reagents invo lved in the CL reaction, including luminol and hexacyanoferrate(III), were both immobilized on an anion-exchange column in FI system. The CL signal pr oduced by the reaction between luminol and hexacyanoferrate(III), which wer e eluted from the column through sodium phosphate injection, was decreased in the presence of folic acid, The CL emission was correlated with the foli c acid concentration in the range from 0.01 to 15 mug ml(-1), and the detec tion limit was 3.5 ng ml(-1) folic acid (3 sigma). At a flow rate of 2.0 ml min(-1), including sampling and washing, could be performed in 2 min with a relative standard deviation of < 2.5%. The flow sensor could be reused mo re than 300 times and has been applied to the analysis of folic acid in pha rmaceutical preparations, and the recovery was from 97.4% to 100.4%. (C) 20 01 Elsevier Science B.V. All rights reserved.