High‐sensitive Electrochemical Determination of Ethyl Carbamate Using Urethanase and Glutamate Dehydrogenase Modified Electrode

Abstract

An amperometric biosensor for ethyl carbamate (EC) was developed for the first time through the cascade reactions of urethanase and glutamate dehydrogenase (GLDH). Urethanase decomposes ethyl carbamate to produce ammonia, which converts to L‐glutamate under the catalysis of GLDH in the presence of α‐ketoglutarate and NADH. Then the change of NADH can be detected chronoamperometrically. The two enzymes were entrapped into chitosan/gelatine/γ‐glycidoxy propyl trimethoxy silane sol‐gel and immobilized on the surface of pyrolytic graphite electrode (PGE). The modified electrode was characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Under the optimized conditions, the amperometric EC biosensor exhibits a linear detection range from 0.5 to 40 μM with a low detection limit of 5.30 nM. The biosensor was successfully used to detect EC in mimic Chinese rice wine samples, and satisfactory recovery and relative standard deviation were achieved.

Comparison of NAD with NADP‐dependent Glutamate Dehydrogenase, and CNT with rGO‐modified Electrodes, for the Construction of Glutamate Sensors

“…There are two types of GDH enzymes and they require either nicotinamide adenine dinucleotide (NAD) or nicotinamide adenine dinucleotide phosphate (NADP) as a coenzyme for their enzymatic activity. Glutamate sensors using separately NAD‐dependent GDH (GDH NAD ) and NADP‐dependent GDH (GDH NAD ) have previously been reported . It should be possible to determine glutamate levels from the anodic oxidation current of NADH and NADPH generated by the enzymatic reaction of GDH.…”

“…It should be possible to determine glutamate levels from the anodic oxidation current of NADH and NADPH generated by the enzymatic reaction of GDH. NADH and NADPH require a high electrical potential for electrolytic oxidation and thus carbon nanotube (CNT) have been used to improve the oxidation capacity of electrodes . The use of CNT‐modified electrodes provides high current response at lower potential compared to other electrode types.…”

“…Glutamate was detected from the anodic current of NADH and NADPH generated by the enzymatic reaction of GDH. The cyclic voltammograms of NADH showed an anodic peak potential ( Ep ) of +0.65 V for a bare GC electrode whereas Ep decreased to +0.45 V for the CNT‐modified electrode, consistent with previous reports of this effect of CNT on the electrolytic oxidation of NADH . In the rGO‐modified electrode, the Ep of NADH decreased to +0.40 V, showing that rGO and CNT are both effective for the electrolytic oxidation of NADH .…”

Fluorescent sensor based on quantum dots and nano‐porphyrin for highly sensitive and specific determination of ethyl carbamate in fermented food

“…A wide variety of analytical methods, including gas chromatography coupled to tandem mass spectrometry (GC-MS/MS), 7,8 High-performance liquid chromatography (HPLC), 9 Fouriertransform infrared (FTIR) spectroscopy, 10 Raman spectrometry, 11 ratiometric fluorescence enzyme-linked immune sorbent assay (RF-ELISA), 12 and other enzymatic assays, 13 have been established for the detection of EC with high specificity and sensitivity. But the methods of GC-MS/MS, HPLC require expensive equipment and complex operational procedures, high technical requirements, and long detection time, FTIR spectroscopy and Raman spectrometry have poor specificity, and ELISA is usually expensive and complicated.…”

Determinação eletroanalítica de pesticidas carbamatos e ditiocarbamatos

“…, o que estava em boa concordância com 0,58 mg.kg -1 detectado pelo método padrão nacional (Padrão Nacional da República Popular da China).Eles concluíram que os resultados foram satisfatórios e que o método eletroanalítico desenvolvido é sensível para a determinação de carbaril em amostras de frutas Zhang et al (ZHANG et al, 2016). desenvolveram um eletrodo de grafite pirolítico modificado com enzimas uretanase e glutamato desidrogenase em solução gel de quitosana/gelatina/g-glicidoxi propiltrimetoxisilano e imobilizada na superfície, para quantificar carbamato de etila em amostras de vinhos de arroz chinês.…”