Determination of trace chlorogenic acid using chemiluminescence in human serum and Flos Lonicerae

It was found that chlorogenic acid could obviously inhibit the chemiluminescence generated from luminol and dissolved oxygen by occurring redox in alkaline medium. The decrease of CL intensity was linearly dependent on chlorogenic acid concentration in the range from 1.0 ng·ml^-1 to 100.0 ng·ml^-1 (r² = 0.9978) offering a detection limit as low as 0.3 ng·ml^-1 (3σ). At a flow rate of 2.0 ml·min^-1, one analysis cycle including sampling and washing, could be accomplished in 20 s with a relative standard deviation of less than 5%. The sensitive flow injection method was applied successfully to determine of chlorogenic acid in human serum and in Flos Lonicerae without any pretreatment procedure, with recovery from 95.8% ~ 108.1%.