Abstract: A novel plant tissue-based chemiluminescence (CL) biosensor for oxalate combined with flow injection analysis is proposed in this paper. The analytical reagents involved in the CL reaction, including luminol and cobalt(II), were both immobilized on an ion exchange resin column, while the biological material spinach tissue was packed in a mini-glass column. By the oxalate oxidase-catalyzed reaction in the plant tissue column, hydrogen peroxide was produced, which could react with luminol and cobalt(II) being released from the ion exchange column by hydrolysis to generate a CL signal. The CL emission intensity was linear with oxalate concentration in the range 0.6-100 µM and the detection limit was 0.2 µM. The biosensor was stable for 300 determinations and a complete analysis, including sampling and washing, could be performed in 2 min with a relative standard deviation of less than 5%.

Abstract: A novel plant tissue-based chemiluminescence (CL) biosensor for urea combined with flow injection analysis is proposed in this paper. The analytical reagents involved in the CL reaction, including luminol and permanganate, were both immobilized on anion exchange resin columns, while the biological material soybean tissue was packed in a mini-glass column. By the urease-catalyzed reaction in the plant tissue column, urea was hydrolyzed to NH4+ and HCO3-. The anion produced could release luminol from the anion-exchange column with immobilized luminol, which then reacted with permanganate eluted from the anion-exchange permaganate column with sodium hydroxide, thus producing a CL signal. The CL emission intensity was linear with urea concentration in the range 4-400 µM; the detection limit was 2 µM. Interfering ions co-existing in urine could be effectively separated on-line by an ion-exchange column placed upstream. The biosensor was applied successfully to the analysis of urea in urine samples.