Electrochemical Biosensor for Nitrite Based on Polyacrylic-Graphene Composite Film with Covalently Immobilized Hemoglobin.

Raja Raja Jamaluddin,Kwok Chong,Ling Tan,Lee Yook Heng

doi:10.3390/s18051343

Raja Raja Jamaluddin, Kwok Chong + Show 2 more

Open Access

https://doi.org/10.3390/s18051343

Copy DOI

Abstract

A new biosensor for the analysis of nitrite in food was developed based on hemoglobin (Hb) covalently immobilized on the succinimide functionalized poly(n-butyl acrylate)-graphene [poly(nBA)-rGO] composite film deposited on a carbon-paste screen-printed electrode (SPE). The immobilized Hb on the poly(nBA)-rGO conducting matrix exhibited electrocatalytic ability for the reduction of nitrite with significant enhancement in the reduction peak at −0.6 V versus Ag/AgCl reference electrode. Thus, direct determination of nitrite can be achieved by monitoring the cathodic peak current signal of the proposed polyacrylic-graphene hybrid film-based voltammetric nitrite biosensor. The nitrite biosensor exhibited a reproducible dynamic linear response range from 0.05–5 mg L−1 nitrite and a detection limit of 0.03 mg L−1. No significant interference was observed by potential interfering ions such as Ca2+, Na+, K+, NH4+, Mg2+, and NO3− ions. Analysis of nitrite in both raw and processed edible bird’s nest (EBN) samples demonstrated recovery of close to 100%. The covalent immobilization of Hb on poly(nBA)-rGO composite film has improved the performance of the electrochemical nitrite biosensor in terms of broader detection range, lower detection limit, and prolonged biosensor stability.

Highlights

Nitrite may occur naturally in waters or foods such as vegetables due to the use of nitrogen-based fertilizer, or may be added to foods to prevent the growth of foodborne pathogenic microorganisms, e.g., the Clostridium botulinum bacterium
The as-synthesized reduced graphene oxide (rGO) has been previously applied in the DNA biosensor fabrication and
The as-synthesized rGO has been previously applied in the DNA biosensor fabrication and characterized by Raman spectroscopy toto study in both bothGO

Summary

Introduction

Nitrite may occur naturally in waters or foods such as vegetables due to the use of nitrogen-based fertilizer, or may be added to foods to prevent the growth of foodborne pathogenic microorganisms, e.g., the Clostridium botulinum bacterium. Nitrite is used extensively in processed food for a specific purpose, to restore color or to improve flavor to a food. It has been proven that excessive nitrite levels in the blood can lead to oxidation of hemoglobin (Hb) [1,2]. Edible bird’s nests (EBNs) containing elevated levels of harmful nitrite have been reported where swiftlet nests were found to contain more than 1000 mg L−1 of nitrite [5]. The continued intake of nitrite can be harmful to human health [6,7], for Chinese pregnant mothers who eat them regularly during their pregnancy stage. A nitrite analysis for all types of EBNs, including “cave” nests and “house” nests, is necessary before they are exported to international markets

Methods

Results

Conclusion