Determination of picomole amounts of thiamine through flow-injection analysis based on the suppression of luminol-KIO(4) chemiluminescence system.

A continuous flow sensor for the determination of thiamine was constructed by using controlled-reagent-release technology in a FIA-CL system. The analytical reagents, luminol and KIO(4), were both immobilized on an anion-exchange column. The CL signal produced by the reaction between luminol and KIO(4), which were eluted from the column through H(2)O injection, was decreased in the presence of thiamine. The decreased CL intensity was linear with thiamine concentration in the range 3.3 pmol ml(-1)-6.7 nmol ml(-1); and the limit of detection was 1.0 pmol ml(-1) (3.). The whole process, including sampling and washing, could be completed in 0.5 min with a relative standard deviation of less than 3.0%. The flow sensor showed remarkable stability and could be easily reused over 80 h. The sensor proposed was tested in determination of thiamine in pharmaceutical preparation and human urine samples.