Quantitative Monitoring of Rutin in Human Urine by Flow Injection‐Chemiluminescence Analysis

In this paper, a rapid and sensitive flow injection‐chemiluminescence ( FI‐CL ) method is proposed for the quantitative determination of rutin based on the inhibitory effect of rutin on the chemiluminescence intensity from the luminol–chymotrypsin ( CT ) system. The decrease of CL intensity was found to be proportional to the logarithm of rutin concentration in the range 0.1–30.0 ng/ mL . A method for the quantification of rutin is proposed, with the limit of detection ( LOD ) of 0.03 ng/ mL (3σ). A complete analytical process including sampling and washing for rutin determination, which was conducted at a flow rate of 2.0  mL /min, could be performed completely within 30 s, yielding a sample efficiency of 120 h −1 . The proposed procedure was successfully applied for the determination of rutin in human urine after oral intake, with recoveries varying from 93.9 to 108.1% and relative standard derivation <4.0% ( n  = 5). Results showed that urine reached the maximum concentration at ~2.5 h, and the total excretion ratios were (83.5 ± 0.6) and (86.8 ± 0.7)%, respectively, for two volunteers in 8 h. The pharmacokinetic parameters, including the half‐life (1.05 ± 0.02 h), absorption rate constant (1.18 ± 0.01 h −1 ), and elimination rate constant (0.70 ± 0.01 h −1 ), were obtained. The possible CL mechanism of the luminol– CT –rutin reaction is discussed by FI‐CL , fluorescence, and molecular docking methods.