Determination of Picogram Levels of Levodopa in Pharmaceutical Preparations and Biofluids by Flow-injection Chemiiuminescence

摘要

An ultrasensitive method for determination of L-dopa at picogram levels by flow-injection chemiiuminescence (FI-CL) as presented for the first time, based on the quenching effect of levodopa (L-dopa) on the luminol-lysozyme reaction. It was found that the decrement of CL intensity was linearly proportional to the logarithm of L-dopa concentration ranging from 3.0 to 7.0 x 10~3 pg mL~(-1) (R = 0.9967), with the limit of detection (LOD) of 1.0 pg mL~(-1) (3σ). The proposed procedure was successfully applied to the determination of L-dopa in pharmaceutical preparations, human saliva, serum, and urine samples with the recoveries ranging from 96.7% to 104.3% and RSDs less than 4.0% in = 5).