Chemiluminescence biosensor system for lactic acid using natural animal tissue as recognition element

A new method based on natural animal tissue porcine kidney as recognition element for chemiluminescence sensing of lactic acid is proposed in this paper. The principle for lactic acid sensing is that lactic acid is oxidized by oxygen under the catalysis of α-hydroxy acid oxidase in the tissue column to produce hydrogen peroxide, which can react with luminol in the presence of potassium ferricyanide to generate a CL signal. The experimental results show that the CL emission intensity was linear with lactic acid concentration in the range of 1-1000 μmol/L and the detection limit (3σ) for lactic acid was 0.2 μmol/L. The biosensor could be used continuously for 6 h with no significant changes in the response. More than 240 measurements were carried out during this time. A complete analysis, including sampling and washing, could be performed in 1.5 min with a relative standard deviation of 1.12% for 100 μmol/L lactic acid. The reproducibility among tissue columns was satisfactory (RSD among columns is less than 5%). The biosensor has been applied successfully to the analysis of lactic acid in plasma and milk samples.