Determination of L-thyroxine in pharmaceutical preparations by flow injection analysis with chemiluminescence detection based on the enhancement of the luminol-KMnO4 reaction in a micellar medium

摘要

A novel flow injection chemiluminescence (CL) method for the determination oft-thyroxine in the presence of cethyltrimethylammonium bromide (CTMAB) surfactant micelles is developed. The method is based on the significant signal enhancement of L-thyroxine on the luminol-KMnO4 system in alkaline solution sensitized by CTMAB. Parameters affecting the reproducibility and CL detection were optimized systematically. Under the optimum conditions, the net CL intensity versus t-thyroxine concentration was linear in the range of 5.0 x 10(-8)-3.0 x 10(-6) mol/L with the detection limit of 8.9 x 10(-9) mol/L. The sample throughput is calculated to be 140 samples/h and the relative standard deviations (RSDs) for 13 replicate determination of 1.0 x 10(-6) L-thyroxine is 1.1%. The proposed method was successfully applied for the determination of L-thyroxine in pharmaceutical preparations with satisfactory recoveries in the range of 93.9-105.2%. This rapid, sensitive, and high throughput method would provide a new tool for t-thyroxine analysis. (C) 2015 Elsevier B.V. All rights reserved.