Sensitive bi-enzymatic biosensor based on polyphenoloxidases–gold nanoparticles–chitosan hybrid film–graphene doped carbon paste electrode for carbamates detection

Abstract

A bi-enzymatic biosensor (LACC-TYR-AuNPs-CS/GPE) for carbamates was prepared in a single step by electro-deposition of a hybrid film onto a graphene doped carbon paste electrode (GPE). Graphene and the gold nanopar-ticles (AuNPs) were morphologically characterized by transmission electron microscopy, X-ray photoelectron spectroscopy, dynamic light scattering and laser Doppler velocimetry. The electrodeposited hybrid film was composed of laccase (LACC), tyrosinase (TYR) and AuNPs entrapped in a chitosan (CS) polymeric matrix. Exper-imental parameters, namely graphene redox state, AuNPs:CS ratio, enzymes concentration, pH and inhibition time were evaluated. LACC-TYR-AuNPs-CS/GPE exhibited an improved Michaelis-Menten kinetic constant (26.9 ± 0.5 M) when compared with LACC-AuNPs-CS/GPE (37.8 ± 0.2 M) and TYR-AuNPs-CS/GPE (52.3 ± 0.4 M). Using 4-aminophenol as substrate at pH 5.5, the device presented wide linear ranges, low detection limits (1.68 × 10 −9 ± 1.18× 10 −10 -2.15 × 10 −7 ± 3.41 × 10 −9 M), high accuracy, sensitivity (1.13 × 10 6 ± 8.11 × 10 4 -2.19 × 10 8 ± 2.51× 10 7 %inhibition M −1 ), repeatability (1.2-5.8% RSD), reproducibility (3.2-6.5% RSD) and stability (ca. twenty days) to determine carbaryl, formetanate hydrochloride, propoxur and ziram in citrus fruits based on their inhibitory capacity on the polyphenoloxidases activity. Recoveries at two fortified levels ranged from 93.8 ± 0.3% (lemon) to 97.8 ± 0.3% (orange). Glucose, citric acid and ascorbic acid do not interfere signifi-cantly in the electroanalysis. The proposed electroanalytical procedure can be a promising tool for food safety control.

Recent advances in biosensors based on enzyme inhibition

“…Gold nanoparticles are characterised by relevant electrochemical properties as reported for instance by Oliveira et al, 2014. In this case the gold nanoparticles were capable to reduce the charge transfer of the laccase/tyrosinase sensor, so a detection of carbamates at a concentration of nanomoles/L was achieved. A sensitive amperometric biosensor with gold nanoparticles was also developed for the detection of methyl paraoxon, carbofuran, and phoxim with AChE immobilised by means of gold nanoparticles and silk fibroin.…”

“…Chitosan, Nafion and conducting polymeric films were usually employed as support for fixation of nanomaterials and enzymes (Oliveira et al, 2014;Moyo et al, 2014b;Can et al, 2012;Gong et al, 2009. To this regards, other materials were also employed, like Cu-Mg-Al calcined layered double hydroxide (Zhai et al, 2014), Mg/Al layered double hydroxides and the polyelectrolyte polydiallyldimethylammonium chloride .…”

A combination of dispersive liquid–liquid microextraction and surface plasmon resonance sensing of gold nanoparticles for the determination of ziram pesticide

“…With increasing use of DTC, ziram determination is imperative . Various methods such as spectrophotometry , atomic absorption spectrometry , chromatography , electrochemistry, FTIR spectrometry , and chemiluminescence have been reported for the ziram determination. However, the standard procedure for ziram assay recommended by Official Methods of Analysis involves acid hydrolysis of this compound, followed by absorption of the produced CS 2 in a methanolic potassium hydroxide solution, and finally iodimetric titration of the formed xanthate .…”

“…In addition, its ability to form strong complexes with trace elements, such as Cu(II), results in an increased trace elements uptake by aquatic organisms [4][5][6][7][8][9].With increasing use of DTC, ziram determination is imperative [10]. Various methods such as spectrophotometry [4,6,11,12], atomic absorption spectrometry [4], chromatography [12,13], electrochemistry [10,[14][15][16][17], FTIR spectrometry [7], and chemiluminescence [1,6] have been reported for the ziram determination. However, the standard procedure for ziram assay recommended by Official Methods of Analysis involves acid hydrolysis of this compound, followed by absorption of the produced CS 2 in a methanolic potassium hydroxide solution, and finally iodimetric titration of the formed xanthate [1].While analyzing the real sample, pretreatment plays a key role because sample contains complex matrix and the low concentrations of fungicides.…”

Determination of Chlorophenol in Environmental Samples Using a Voltammetric Biosensor Based on Hybrid Nanocomposite

“…7, 2017 sample; the analysis is carried out in seconds and they present high selectivity. 12 Selectivity also increases when the recognizing element is an enzyme as in the case of laccase, which is useful in detection of phenols. 13 Currently there are few reports related to the determination of chlorophenols using biosensors due to difficulties arising from the fact that these compounds have the ability to generate intermediates, thus forming polymeric structures that crust on the electrode surface.…”