Electrochemical Biosensor for Detection of Perfluorooctane Sulfonate Based on Inhibition Biocatalysis of Enzymatic Fuel Cell

Abstract

An electrochemical biosensor for sensitive detection of perfluorooctane sulfonate (PFOS) was developed based on the PFOS inhibition influence on the biocatalysis process of enzymatic biofuel cell (BFC). The one-compartment BFC was prepared used multi-walled carbon nanohorns (MWNHs) modified glassy carbon electrodes (GCE) as the substrates for both bioanode and biocathode, and glutamic dehydrogenase (GLDH) and bilirubin oxidase (BOD) acted as biocatalysts of bioanode and biocathode, respectively. The BFC generated an open circuit potential (V_oc) of 30.65 mV and a maximum power density of 27.5 µW/cm². After interaction times of 20 min, a wide linear range from 5 to 500 nmol/L between ΔV_oc and PFOS concentration was achieved with good correlation R² = 0.976 and number of measurements is three times (n = 3), and the detection limit was 1.6 nmol/L. Furthermore, we choose 4 kinds of perfluorinated chemicals, whose structures are similar with PFOS, including perfluorooctanoic acid (PFOA), nonafluorobutanesulfonic acid potassium (PFBSK), perfluorooctanesulfonamide (PFOSA) and heptadecafluorononanoic acid (PFNA), and 2 kinds of chemicals (SMNBS and SDS), which co-exist with PFOS in micro-polluted water and could possibly disturb the PFOS detection. The electrochemical biosensor exhibited good selectivity for PFOS against these chemicals. High precision with relative standard deviation (RSD) (n = 3) from 3.6 to 7.7% for PFOS detection in real water samples was also demonstrated by the standard addition method. Results obtained in this study indicated that this electrochemical biosensor could be successfully used for selective detection of PFOS in real micro-polluted water.