Highly selective determination of cysteine using a composite prepared from multiwalled carbon nanotubes and gold nanoparticles stabilized with calcium crosslinked pectin

作者：Devasenathipathy Rajkumar; Karuppiah Chelladurai; Chen Shen Ming^*; Mani Veerappan; Vasantha Vairadevar Sivasamy; Ramaraj Sayeekannan

来源：Microchimica Acta, 2015, 182(3-4): 727-735.

DOI：10.1007/s00604-014-1380-9

• Multiwalled carbon nanotubes
• Pectin
• Electrodeposition
• Gold nanoparticles
• L-Cysteine
• Amperometry

We describe a glassy carbon electrode (GCE) modified with gold nanoparticles that were stabilized with calcium-crosslinked pectin (CCLP) and electrodeposited on multiwalled carbon nanotubes (MWCNTs) by cyclic voltammetry. The resulting electrode was used for the selective determination of L-cysteine (L-Cys). Its characterization showed that the CCLP acts as a scaffold to form highly stable, uniform and electrochemically active AuNPs. Electrochemical studies showed the MWCNT to significantly promote the electrodeposition of the CCLP-AuNPs. The new GCE exhibited excellent electrocatalytic ability towards oxidation of L-Cys in showing a lower overpotential and giving a higher oxidation peak current. The diffusion coefficient for the oxidation of L-Cys was calculated to be 3.0 x 10(-6) cm(2) s(-1). This amperometric sensor displays a wide linear range (from 0.1 to 1,000 mu M), high sensitivity (0.46 mu A mu M-1 cm(-2)) and a detection limit as low as 19 nM (at a signal-to-noise ratio of 3). The sensor was applied to specifically detect L-Cys even in the presence of 500-fold excess of interferents. It also is stable and possesses good repeatability and reproducibity, and was successfully applied to the determination of L-Cys in spiked samples of human serum.

• 出版日期2015-2