Enhanced electrochemical reduction of hydrogen peroxide at metallic electrodes modified with surfactant and salt

A biosensor for the determination of high density lipoprotein cholesterol employing combined surfactant-derived selectivity and sensitivity enhancements

“…In the absence of surfactant, electrodes had a response of 1.33×10 -7 A (curve 1). However, in the presence of 6% (v/v) Emulgen B-66, a response of 5.98×10 -6 A was obtained for 3 mM H 2 O 2 (curve 3), which was a 39% current increase over that 50 achieved for the previously reported 16 combination of DBSA and KCl of 3.64×10 -6 A (curve 2). This enhanced response might assist in achieving a lower limit of detection of H 2 O 2 with the sensor.…”

“…Thus, it would seem a common 20 sense approach to develop electrochemical biosensor methodologies that are capable of measuring HDL-C using a similar principle, with the measurement of H 2 O 2 performed electrochemically. 15,16 While a number of electrochemical biosensors for cholesterol have been developed, [17][18][19][20][20][21][22][23][24][25][26][27][28][29][30] to date, 25 there are just a few published examples of electrochemical biosensors for HDL-C. 31,32 Kinoshita et al, developed an amperometric sensor based on a homogeneous assay in which, a peroxidase-entrapped and ferrocene-embeded carbon paste electrode was used to measure the H 2 O 2 produced after enzymatic 30 reaction of HDL-C. PEG-modified enzymes in the presence of -cyclodextrin sulphate and MgCl 2 were employed to impart selectivity to the measurement of HDL-C. This method was performed at 37°C and was only linear up to 0.04 mM.…”

“…It has been shown previously that these electrodes, modified with lyotropic layers composed of surfactant and salt, exhibit the significantly enhanced electrocatalytic reduction of H 2 O 2 . 15,16 …”

“…As previously demonstrated, the electrocatalytic reduction of H 2 O 2 has been shown to be significantly enhanced at a screen printed, silver paste electrode modified with a lytropic layer formed by surfactant and electrolyte. 16 The mechanism for this is not fully understood, but may be due to several effects including 5 a change in silver paste morphology by creating a high surface area nanostructure, or the formation of micellar, hexagonal or lamellar structures by surfactant in the solution which become deposited onto the silver paste and creates an enhanced surface for the catalytic process. 16,38 Emulgen B-66 is a nonionic 10 surfactant which was prepared in an electrolyte solution of 0.1 M PBS pH 6.8.…”

“…16 The mechanism for this is not fully understood, but may be due to several effects including 5 a change in silver paste morphology by creating a high surface area nanostructure, or the formation of micellar, hexagonal or lamellar structures by surfactant in the solution which become deposited onto the silver paste and creates an enhanced surface for the catalytic process. 16,38 Emulgen B-66 is a nonionic 10 surfactant which was prepared in an electrolyte solution of 0.1 M PBS pH 6.8. It is believed that an equivalent effect is achieved by this combination as has previously been demonstrated with other surfactant/salt combinations.…”