Investigation of the binding of AuNPs-6-mercaptopurine and the sensitive detection of 6-mercaptopurine using resonance Rayleigh light scattering.

A highly sensitive method for the detection of 6-mercaptopurine (MP) by resonance Rayleigh light scattering (RLS) method was developed. Gold nanoparticles (AuNPs) were synthesized by a modified seed method and characterized using transmission electron microscopy (TEM). AuNPs were bound to MP via covalent bonding to form the MP-AuNPs complex, which increased the RLS intensity of MP at 347 nm (increased by 65.7%). Under optimum conditions, the magnitude of the enhanced RLS intensity for MP-AuNPs was proportional to MP concentration in the range 0.0681-1.702 μg mL⁻¹. The linear regression equation was represented as follows: Δ I _RLS = 9.31 + 82.42 c ( r = 0.9948). The limit of detection (LOD, 3σ) was 3.32 ng mL⁻¹. The system was applied successfully to detect MP in pharmaceuticals. MP recoveries were 99.9-101.7% with a relative standard deviation (RSD) ( n = 5) of 0.59-0.77% for three synthetic samples, and 97.5-110.0% with an RSD of 0.98-2.10% ( n = 5) for tablet samples. [ABSTRACT FROM AUTHOR]