Sensitive determination of catechol using a glassy carbon electrode modified with L-cysteine and ZnS:Ni/ZnS quantum dots

In this work, water-soluble ZnS:Ni/ZnS quantum dots (QDs) with core/shell structure were obtained successfully using mercaptoacetic acid as dressing agent, which were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, atomic force microscopy and transmission electron microscopy. A highly sensitive and stable electrochemical sensor was developed by immobilizing L-cysteine and ZnS:Ni/ZnS QDs on the surface of glassy carbon electrode. The sensor showed excellent catalytic activity to catechol (CC). Experimental results showed that the oxidation peak current of CC was linear over the range from 0.5 to 100 μM, and the detection limit (S/N = 3) for CC was 32 nM. The developed sensor was successfully used for determination of CC in lake water samples with satisfactory recoveries.