r Ojani - Elect roanalytical C hemistry Resea rch Laboratory, Department of Analytical Chemistry, Faculty of Chemistry, University of Mazandaran, Babolsar, Iran
a Alinezhad - Elect roanalytical C hemistry Resea rch Laboratory, Department of Analytical Chemistry, Faculty of Chemistry, University of Mazandaran, Babolsar, Iran
z Abedi - Elect roanalytical C hemistry Resea rch Laboratory, Department of Analytical Chemistry, Faculty of Chemistry, University of Mazandaran, Babolsar, Iran

Uric acid (UA), xanthine (X A) are degradation products of purine metabolism in human and animals. Purine m etabolites pathway inv olves trans formation of HX XA, XA UA by xanthine oxidase, so XA is intermediate a nd UA is th e terminal p roduct of purine degrad ation metabolism [۱]. T he concent ration levels of the two products i n body fluids such as human serum and urine are markers of many clinical con ditions, inc luding hyperuricemia, gout,leuke mia, xanthi uria and pneumonia [ ۲]. Gold nanoparticles are the m ost stable metal nanoparticles, which present ed fascinati ng features such as the assembly of multiple types involving materials science, the behavio r of indivi dual particle , size-relate d electronic and optical properties (quantum size effect) and their applications to catalysis and biology [۳]. With the help of a long chain molecule having suitable functional groups at both ends, the gold nanoparticles can be immobilized as an organized mono- or m ultiparticle layer on a solid support [۴,۵]. In this paper, electroche mical resp onses of UA and XA at the poly L- methi onine(PLMT )/gold nanoparticle(AuNPs) wer e compared with the electrochemical respon ses of UA and XA at the PLMT modified electrode and GCE. Finally, modified electr ode was successfully e mployed to detect UA and XA in the serum samples with good selectivity and high sensitivity .

Poly L-methionine (PLMT), Gold nanop article (Au NPs)