A colorimetric method for the determination of xanthine based on the aggregation of gold nanoparticles
- 489 Downloads
We describe a highly sensitive method for the determination of traces of xanthine based on the aggregation of citrate-stabilized gold nanoparticles (AuNPs). It is found that, under optimal conditions of pH, the imide group of xanthine is adsorbed on the surface of the AuNPs, thereby displacing citrate ions. This leads to an aggregation of the AuNPs via hydrogen-bond interactions. As a result, the color of the solution changes from red to blue which can be seen with bare eyes and also can be measured by spectrophotometry. The ratio of the absorbances at 630 nm and 520 nm is linearly related to the concentration of xanthine in the 125 nM to 6.0 μM range (r = 0.9988), and the detection limit (3σ/slope) is 23 nM. The method is simple, feasible and fast.
KeywordsXanthine Gold nanoparticles Aggregation Detection
This work was supported by the Chongqing Natural Science Foundation (CSTC, 2007BB0049) and the National Natural Science Foundation Committee of China.
- 24.Kulikowska E, Kierdaszuk B, Shugar D (2004) Xanthine, xanthosine and its nucleotides: solution structures of neutral and ionic forms, and relevance to substrate properties in various enzyme systems and metabolic pathways. Acta Biochim Pol 51:493–531Google Scholar