It was found that the complex of cytochrome c (Cyt c) and hydrogen peroxide could significantly catalyze the chemiluminescence (CL) reaction from luminol-hydrogen peroxide, and a sensitive, rapid, and simple CL procedure was proposed for the determination of Cyt c in a flow injection system for the first time. The increment of CL intensity was linear over the concentration of Cyt c ranging from 5 to 700 ng ml(-1), with a detection limit of 2 ng ml(-1) (3sigma). At a flow rate of 2.0 ml min(-1), a complete analytical process could be performed in 30 s with a relative standard deviation of less than 4.0%. The proposed method was applied successfully for the assay of Cyt c in pharmaceutical injections and human serum, and the recoveries were from 98.0% to 108.8% and 92.5% to 109.0%. The possible mechanism of Cyt c enhanced CL reaction was also discussed.
A novel chemiluminescence method for the assay of sudan I was designed using flow injection with chemiluminescence detection. The proposed method was based on the increment effect of sudan I on the chemiluminescence intensity in the luminol–KIO4system. The increment of chemiluminescence intensity was correlated with the sudan I concentration in the range from 0.1 to 10 pg ml−1, and the determination could be performed in 0.5 min in flow rate of 2 ml min−1, including sampling and washing, giving a throughput of 120 h−1with a relative standard deviation of less than 5.0%. The method had been successfully applied to the assay of sudan I in Pixian douban, Golden mark guilin chilli sauce and Golden mark satay sauce, and the recovery was 90.0–103.8%.
A sensitive flow injection chemiluminescence method, based on the inhibitory effect of chlorogenic acid on the reaction between luminol and dissolved oxygen, was presented for the determination of chlorogenic acid. It was found that the decrease of chemiluminescence intensity was linear with the logarithm of chlorogenic acid concentration over the range from 1.0 ng.ml(-1) to 100 ng.ml(-1) (r(2) = 0.9978), with the detection limit of 0.3 ng.ml(-1) (3 sigma). At the flow rate of 2.0 ml.min(-1) for each line, a complete analytical process could be performed within 0.5 min, including sampling and washing, with a relative standard deviation lower than 3.0% (n = 5). The proposed procedure was applied successfully to determine chlorogenic acid in Flo Lonicerae for different drawn time and monitor the excretion of chlorogenic acid in human urine. It was found that the excretive amounts of chlorogenic acid in urine reached its maximum in 2 hours after intake of Flo Lonicerae tea, presenting an excretive ratio of 63.82% in 6 hours. With urinary excretion rate method, the total elimination rate constant k and half-life time t(1/2) of chlorogenic acid was calculated, which were 0.7667 and 0.91 hours, respectively.
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