Amperometric sensor for nitrite using a glassy carbon electrode modified with thionine functionalized MWCNTs/Au nanorods/SDS nanohybrids

Abstract

A sensitive nitrite (NO 2 -) biosensor was fabricated by using sodium dodecyl sulfate (SDS), Au nanorods, and thionine functionalized MWCNTs (TH-f-MWCNTs) nanohybrids modified glassy carbon electrode. TH was covalently immobilized on the MWCNTs via a carbodiimide reaction. Comparing with MWCNTs/GCE, TH-f-MWCNTs/GCE displays higher catalytic activity toward the oxidation of NO 2 -, since TH not only promoted the electronic transmission but also could improve the concentration of NO 2 at the surface of the modified electrode in acidic solutions. The Au nanorods (AuNRs) were prepared through a simple wet chemical method and were characterized by TEM. The extremely high surface-to-volume ratios associated with one dimension nanostructures make their electrical properties extremely sensitive to species adsorbed on surfaces and result in excellent sensitivity and selectivity. SDS displays excellent film forming ability, which made the electrode stable. Under optimal conditions, the linear range for the detection of nitrite was 0.26 to 51 mM, and the low detection limit was 20 nM. In addition, the modified electrode was successfully applied to determine nitrite in real water samples.

Coating and Immobilization of Sensors

“…Figure 4.2 shows interdigital sensors fabricated on FR4 coated with different materials. The Carboxyl-funtional polymer [3], APTES (3-aminopropyltrietoxysilane) [2,4] and Thionine (a blue organic dye) [5,6] were introduced as coating materials which have been widely used in the development of chemical sensors and biosensors. The objective is to study if these coatings could improve the performance and the selectivity of the sensors.…”

P1NM.7 - Detection of Nitrite by Copper Interdigitated Electrode with Nickel-Cobalt Nanowires

“…Moreover, electrochemical approaches, e.g. cyclic voltammetry [10][11][12], are also widely used to measure nitrite ions. Electrochemical methods have advantages of easy operation and fast response.…”