Resonance light scattering determination of 6-mercaptopurine coupled with HPLC technique

• A simple, fast, costless, sensitive method of Resonance light scattering coupled with HPLC for the analysis of 6-mercaptopurine in human urine was established.
• There were no complicated derivatization procedure involved in the proposed method.
• The reation mechanism and possible reasons for enhancement of RLS were fully discussed in this work.

A simple, fast, costless, sensitive and selective method of resonance light scattering coupled with HPLC was established for the determination of 6-mercaptopurine in human urine sample. In a Britton–Robinson buffer solution of pH 5.5, the formation of coordination complex between 6-mercaptopurine and metal palladium (II) led to enhance the RLS intensity of the system. The RLS signal was detected by fluorescence detector at λex = λem = 315 nm. The analytical parameters were provided by the coupled system, the linear of 6-mercaptopurine response from 0.0615 to 2.40 μg L− 1 and the limit of detection (S/N = 3) was 0.05 μg L− 1. The presented method has been applied to determine 6-mercaptopurine in human urine samples which obtained satisfactory results. Moreover, the reaction mechanism and possible reasons for enhancement of RLS were fully discussed.

When 6-mercaptopurine reacted with palladium chloride to form the neutral complex, a hydrophobic interface was formed between the coordination complex and the aqueous phase, which is advantageous to the enhancement of RLS. The congregated complex formed by the squeezing effect of aqueous phase and Vander Waals force is the main reason for the enhancement of scattering since congregation enlarges the volume of the scattered molecular. Coordinated product was validated by the application of Job's method of continuous variation and molar ratio method. It showed that the reaction was produced by mixing the two substances in the composition ratio of 2:1. Based on mole ratio and infrared spectra, the following reaction was speculated:Figure optionsDownload as PowerPoint slide