Monocrystalline silicon/polyaniline/horseradish peroxidase enzyme electrode obtained by the electrodeposition method for the electrochemical detection of glyphosate (original) (raw)
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Microchemical Journal, 2021
Glyphosate is the most widely used herbicide in Argentina. The information about this herbicide is controversial as some organisms classify it as dangerous and others as safety. Moreover, the world regulations are very different depending on country. However, many studies had reported its presence in numerous sample types, and also, had demonstrated adverse effects on environmental and human health. In the present work, two electrochemical screening methods based on horseradish peroxidase (HRP) inhibition have been developed for the glyphosate detection. In one of them, the working electrode was built in our laboratory with a graphite-epoxy compound mixture (GEC-E). While the other is based on a biosensor built with commercial screen-printed electrodes (SPE), for which on the working electrode, the HRP enzyme was immobilized by using the affinity reaction between streptavidin and biotin-peroxidase. The detection electrochemical technique was square-wave voltammetry (SWV). When glyphosate inhibits the activity of the soluble or immobilized enzyme, a decrease in the signal is generated at the electrode or biosensor, respectively, and this decrease is proportional to the amount of glyphosate in the sample. The linear range obtained was from 0.16 to 500 ng L-1 glyphosate (R 2 = 0.9727) for the soluble HRP-based inhibition method with a limit of detection (LOD) of 0.085 ng L-1. While the range was from 0.08 to 11 μg L-1 glyphosate (R 2 = 0.9799) for immobilized HRP-based inhibition method with a LOD of 45 ng L-1. For the screening detection of glyphosate, the decision limits (CCα) and detection capabilities (CCβ) were 115 and 130 ng L-1 for the soluble HRP-based inhibition method and 111 and 122 ng L-1 for biosensor, respectively. Recoveries from 71% to 96% and from 79% to 120% were obtained by two electrochemical methods from groundwater and superficial water with high organic matters spiked with glyphosate, respectively. Therefore, both electrochemical methods allow determining the glyphosate concentration at trace levels in accordance with the strictest European Parliament regulation (100 ng L-1). The soluble HRP-based inhibition method shown better performance than biosensor, but the latter due to its simplicity, stability and portability could be used in the field monitoring or detection of this herbicide in the exposed areas.
Biosensor based on atemoya peroxidase immobilised on modified nanoclay for glyphosate biomonitoring
Talanta, 2012
A biosensor based on atemoya peroxidase immobilised on modified nanoclay was developed for the determination of glyphosate by the enzyme inhibition method. The inhibitor effect of the biocide results in a decrease in the current response of the hydroquinone that was used as a phenolic substrate to obtain the base signal. The biosensor was constructed using graphite powder, multiwalled carbon nanotubes, peroxidase immobilised on nanoclay and mineral oil. Square-wave voltammetry was utilised for the optimisation and application of the biosensor, and several parameters were investigated to determine the optimum experimental conditions. The best performance was obtained using a 0.1 mol L À 1 phosphate buffer solution (pH 7.0), 1.9 Â 10 À 4 mol L À 1 hydrogen peroxide, a frequency of 30 Hz, a pulse amplitude of 50 mV and a scan increment of 4 mV. The glyphosate concentration response was linear between 0.10 and 4.55 mg L À 1 with a detection limit of 30 mg L À 1 . The average recovery of glyphosate from spiked water samples ranged from 94.9 to 108.9%. The biosensor remained stable for a period of eight weeks.
Electrochemical Nanobiosensor for Glyphosate Herbicide and Its Metabolite
Electroanalysis, 2009
The use of amperometric biosensor for the detection of glyphosate herbicide and its metabolite aminomethylphosphonic acid (AMPA) is presented. The biosensor was developed by electrochemically depositing poly(2,5dimethoxyaniline) (PDMA) doped with poly(4-styrenesulfonic acid) (PSS) onto the surface of a gold electrode followed by electrostatic attachment of horseradish peroxidase (HRP) onto the PDMA-PSS nanocomposite film. The PDMA-PSS film was characterized by transmission electron microscopy (TEM) and Fourier Transform infrared (FTIR) spectroscopy. The HRP immobilized on the PDMA-PSS film catalyzed the reduction of hydrogen peroxide, the inhibition of which was applied in the detection of glyphosate and AMPA. The limits of detection of the biosensor for glyphosate and AMPA were 0.16 mg L À1 and 1.0 mg L À1 , respectively. The study demonstrates that the biosensor is very sensitive and could be a useful tool in the screening of glyphosate and AMPA at low concentrations.
Recent Advances in Non-Enzymatic Electrochemical Sensors for Glyphosate Detection: A Review
Glyphosate (GLY) is the most widely used organophosphorus pesticides globally with application in shielding crops against perennial and annual the weeds, domestic garden and agriculture. It is recognized for its toxicological harm and is implicated in potential connections with human carcinogenesis. Generally, glyphosate is considered to be less toxic but excessive use leads to pollute soil, food and water. Furthermore, it strongly effects the unicellular and multicellular organism. Therefore, there is urgent need to develop specific, accurate, online, and sensitive methods for detection of glyphosate. The present review is focused on recent advances in developing non-enzymatic sensors for glyphosate detection. Non-enzymatic electrochemical sensors have emerged as promising alternatives for glyphosate detection, offering advantages such as high sensitivity, selectivity, and rapid response. The electrodes were modified with metals, carbon materials, metal organic framework and molecular imprinted polymers using various electrochemical techniques. Execution, benefits, linear range, detection limit and limitations of the modified sensors for determination of glyphosate are reviewed thoroughly.
Enzyme and Microbial …, 2013
A novel electrochemical biosensor for the determination of pyrogallol (PG) and hydroquinone (HQ) has been constructed based on the poly l-arginine (poly(l-Arg))/carbon paste electrode (CPE) immobilized with horseradish peroxidase (HRP) and silver nanoparticles (AgNPs) through the silica sol-gel (SiSG) entrapment. The electrochemical properties of the biosensor were characterized by employing the electrochemical techniques. The proposed biosensor showed a high sensitivity and fast response toward the determination of PG and HQ around 0.18 V. Under the optimized conditions, the anodic peak current of PG and HQ was linear with the concentration range of 8 M to 30 × 10 −5 M and 1-150 M. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 6.2 M, 20 M for PG and 0.57 M, 1.92 M for HQ respectively. The electrochemical impedance spectroscopy (EIS) studies have confirmed that the occurrence of electron transfer at HRP-SiSG/AgNPs/poly(l-Arg)/CPE was faster. Moreover the stability, reproducibility and repeatability of the biosensor were also studied. The proposed biosensor was successfully applied for the determination of PG and HQ in real samples and the results were found to be satisfactory.
Biosensors & Bioelectronics, 2010
Direct electron transfer process of immobilized horseradish peroxidase (HRP) on a conducting polymer film, and its application as a biosensor for H 2 O 2 , were investigated by using electrochemical methods. The HRP was immobilized by covalent bonding between amino group of the HRP and carboxylic acid group of 5,2?:5?,2ƒ-terthiophene-3?-carboxylic acid polymer (TCAP) which is present on a glassy carbon (GC). A pair of redox peaks attributed to the direct redox process of HRP immobilized on the biosensor electrode were observed at the HRP j TCAP j GC electrode in a 10 mM phosphate buffer solution (pH 7.4). The surface coverage of the HRP immobilized on TCAP j GC was about 1.2)/10 (12 mol cm (2 and the electron transfer rate (ks ) was determined to be 1.03 s (1 . The HRP j TCAP j GC electrode acted as a sensor and displayed an excellent specific electrocatalytic response to the reduction of H 2 O 2 without the aid of an electron transfer mediator. The calibration range of H 2 O 2 was determined from 0.3 Á/1.5 mM with a good linear relation. #
Enzyme and Microbial Technology, 2013
A novel electrochemical biosensor for the determination of pyrogallol (PG) and hydroquinone (HQ) has been constructed based on the poly l-arginine (poly(l-Arg))/carbon paste electrode (CPE) immobilized with horseradish peroxidase (HRP) and silver nanoparticles (AgNPs) through the silica sol-gel (SiSG) entrapment. The electrochemical properties of the biosensor were characterized by employing the electrochemical techniques. The proposed biosensor showed a high sensitivity and fast response toward the determination of PG and HQ around 0.18 V. Under the optimized conditions, the anodic peak current of PG and HQ was linear with the concentration range of 8 M to 30 × 10 −5 M and 1-150 M. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 6.2 M, 20 M for PG and 0.57 M, 1.92 M for HQ respectively. The electrochemical impedance spectroscopy (EIS) studies have confirmed that the occurrence of electron transfer at HRP-SiSG/AgNPs/poly(l-Arg)/CPE was faster. Moreover the stability, reproducibility and repeatability of the biosensor were also studied. The proposed biosensor was successfully applied for the determination of PG and HQ in real samples and the results were found to be satisfactory.
Electrochemical biosensors based on horseradish peroxidase
Russian Journal of General Chemistry, 2008
The principles used for the development of electrochemical biosensors based on horseradish peroxidase are described. Peroxidase is the enzyme which catalyses the oxidation of a variety of organic molecules in the presence of hydrogen peroxide. The features of this enzyme are high catalytic activity and low specificity towards second substrate as well. Horseradish peroxidase may be used as a component of active part of biosensors for the detection of hydrogen peroxide and other compounds when peroxidase is co-immobilized together with other oxidases. Also horseradish peroxidase may be used as a component of detecting system for the biosensors based on biological recognition using specific antibodies, receptors, nucleic acids. The examples of the bio-, immuno-, DNA-sensors developed for the determination of various biologically active compounds are given.