Highly Sensitive and Wide Range Non-Enzymatic Electrochemical Detection of Cholesterol using Pencil Lead Electrodes

Electrochemical detection of cholesterol has been carried out on pencil lead electrode (PLE) in acetonitrile and acetone (1:1 v/v %) containing 0.3 M lithium perchlorate. The PLEs were explored for the first time for the detection of cholesterol in an organic medium. The electrodes were thoroughly characterized by microscopy and diffraction studies. The PLE exhibited a wide linear range of detection from 0.625 to 9.375 mM and high sensitivity of 1455.22 mu A mM(-1) cm(-2). These characteristics point to the superior performance of the sensor when compared with that reported in the organic medium. The unmodified PLE was highly specific to cholesterol in the presence of commonly interfering biomolecules such as uric acid, dopamine, glucose, ascorbic acid, creatinine and proteins. Calibration plots for real samples were constructed by spiking 0.625-9.375 mM of cholesterol to serum and skin cholesterol samples. In both samples, the PLE show a highly linear response.