Amperometric Determination of Serum Cholesterol with Pencil Graphite Rod

Abstract

A cholesterol oxidase from Streptomycin sp. was immobilized onto pencil graphite rod and employed for amperometric determination of serum cholesterol. The method has the advantage over earlier amperometric methods that it requires low potential to generate electrons from H2O2, which does not allow ionization of serum substances. The optimum working conditions of amperometric determination were pH 6.8, 25?C and 30 s. The current measured was in proportion to cholesterol concentration ranging from 1.29×10-3 to 10.33×10-3 M. Minimum detection limit of the method was 0.09 ×10-3 M. Mean analytical recovery of added cholesterol (100 mg/dl and 200 mg/dl) in serum was 85.0% & 90.0% respectively. Within batch and between batch coefficients of variations were 1.59% & 4.15% respectively. A good correlation (r = 0.99) was obtained between serum cholesterol values by standard enzymic colorimetric method and the present method. No interference by metabolites was observed in the method. The enzyme electrode was reused 200 times over a period of 25 days, when stored at 4?

Development of a novel biosensor based on a polypyrrole–dodecylbenzene sulphonate (PPy–DBS) film for the determination of amperometric cholesterol

“…Temperature exerts a marked influence on the enzymatic activity as well as on the performance of the amperometric cholesterol biosensor employed in this work, the sensitivity of which increases at lower temperatures. The effect of this parameter on the sensor response was evaluated in the range 20-70 C. As illustrated in Figure 15, the current response gradually increased with increasing temperature and reached a maximum at 50 C. This value is higher than those in many other studies (Basu et al 2007, Chauhan et al 2010, Singh et al 2004, Singh et al 2006, Turkarslan et al 2009. This was attributed to the fact that the used polymer and immobilization materials and the type of immobilization were different.…”

Reusable and Mediator-Free Cholesterol Biosensor Based on Cholesterol Oxidase Immobilized onto TGA-SAM Modified Smart Bio-Chips

“…In order to check the accuracy of the developed methods, analytical recovery of added cholesterol in five real serum samples was investigated. The mean analytical recovery of added cholesterol (∼2.76 mM) in serum was 92.1±1.5% (n = 5), which was higher than pencil graphite rod electrode by amperometric method [65]. The simple fabrication method of the biosensor has several advantages over conventional technique such as ease of fabrication, enhanced electro-catalysis, and efficiently preserving the activity of bio-molecules.…”

Pencil drawn paper based supercapacitors

“…Recently the possibility for using pencils to draw electrodes and other electronic components onto a suitable substrate, from paper to lithium superionic conductor films, has been reported 3 . Such approaches have a number of advantages; allowing the designs and geometries to be easily altered, as they are simply drawn by hand onto a suitable substrate [4][5][6][7][8][9][10] . This allows an extremely facile, green, lowcost, rapid method to fabricate electrode prototypes.…”