Plant tissue-based chemiluminescence flow biosensor for oxalate

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 mu M and the detection limit was 0.2 mu M. 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%.