Detection Of Methyl Parathion Research Articles

ZnO hollow spheres arrayed molecularly-printed-polymer based selective electrochemical sensor for methyl-parathion pesticide detection

A highly sensitive electrochemical-based detector was fabricated to selectively sense methyl-parathion (MP). A Glassy carbon electrode (GCE) was functionalized with zinc oxide (ZnO) hollow spheres (ZnOHS) and a molecularly imprinted polymer (MIP) to form the developed sensor. Cyclic voltammetry (CV) was performed to synthesize a molecularly imprinted polymeric film on the ZnOHS modified GCE (GCE/ZnOHS) by electropolymerization of functional monomer, l-arginine (L-Arg), and template molecule, MP. The differential pulse voltammetry (DPV) was utilized to evaluate the efficiency of the electrochemical detection of MP under optimal conditions by the proposed sensor. The developed sensor recorded a good performance for detecting MP in the linear range of 5 × 10 −9 to 0.1 × 10 −4 mol L −1 ( R 2 = 0 .985) with a detection limit (S/N = 3) of 0.5 × 10 −9 mol L −1 and sensitivity of 571 nA/ μ molL −1 cm −2 . This electrochemical sensing system effectively detects MP in real samples with satisfactory recoveries of 90.4%, 91.9%, 118%, and 96.3% for fresh green beans, strawberry, tomato, and cabbage, respectively. • Electrochemical biosensing platform helps to detect methyl parathion in environment. • ZnOHS arrayed MIP electrochemical sensor was developed for MP detection. • The developed GCE/ZnOHS/MIP sensor showed a sensitive and selective response to MP. • The proposed sensor showed good sensitivity, stability, and reproducibility.

Transparent and flexible AuNSs/PDMS-based SERS substrates for in-situ detection of pesticide residues

Herein, we developed a PDMS-based flexible SERS substrate modified with gold nanostars (AuNSs) for in-situ detection of pesticide residues on fruit surfaces. AuNSs with sharp branches were assembled on aminated PDMS membrane by chemical bonding effect. The AuNSs/PDMS substrate showed good signal uniformity, stability and sensitivity using the Raman signal molecule 4-MBA and the detection concentration of 4-MBA was as low as 10−8 mol/L. Then the AuNSs/PDMS substrate was used to detect methyl parathion (MP) standard solution. A good linear relationship between SERS intensity at 1342 cm−1 and MP concentration was established in the range of 4 μg/mL–100 μg/mL, and the limit of detection was down to 1.946 μg/mL. Moreover, the AuNSs/PDMS substrate was directly covered on the surface of MP contaminated apple, and the Raman laser was incident from the back of substrate to achieve in-situ detection of pesticide residues. The recovery ratio indicated that the fabricated SERS substrate was realized successfully in real sample detection. AuNSs/PDMS substrate eliminates the requirement for sample pre-processing steps before testing, which can be used as a method for rapid inspection of pesticide in agricultural products on site.

Combine etching-doping sedimentation strategy and carbonization to design double-deck petal-like NiO/CoO nanoporous carbon composite for methyl parathion detection

Designing efficient and rapid methods for detection of pesticide residue is one of the prerequisites to reduce its negative health influences. Herein, we constructed an electrochemical sensor for efficient detection of Methyl parathion (MP) using a double-deck petal-like NiO/CoO nanoporous carbon composite (Z-NiO/CoO@CC). The Z-NiO/CoO@CC was fabricated through etching-doping sedimentation strategy and carbonized conversion. The elaborate electrocatalyst not only created the structural advantages to offer more activities sites for the target analyte, but also had compositional virtues by combining the carbon nano-frame (originating from zeolitic imidazolate framework, ZIF-67) and bimetal oxides to enhance electrochemical performances. Besides, the electro-catalysis mechanism and detection performance of the prepared electrode were also detailly studied through different electrochemical techniques. Under optimized conditions, the prepared Z-NiO/CoO@CC showed favorable performance for MP detection with linear range from 10 ng/mL to 10 μg/mL, high sensitivity of 12.8 μA μM−1 cm−2 and low detection limit of 3.6 ng/mL (S/N = 3). Moreover, the practical feasibility of the Z-NiO/CoO@CC was also verified through monitoring MP in tap water and grape samples. This work has explored a novel method for construction of high-performance electrochemical MP sensors.

Non-Enzymatic Methyl Parathion Electrochemical Sensor Based on Hydroxyl Functionalized Ionic Liquid/Zeolitic Imidazolate Framework Composites Modified Glassy Carbon Electrode

A non-enzymatic methyl parathion (MP) electrochemical sensor was fabricated based on hydroxyl functionalized ionic liquid/zeolitic imidazolate framework composites modified glassy carbon electrode (IL-ZIF-67/GCE). Scanning electron microscopy (SEM) was used to study the surface morphologies of the modified electrodes. ZIF-67 could be well dispersed by hydroxyl functionalized ionic liquid. The structures of the modification materials were characterized using Fourier transform infrared spectroscopy (FT-IR). Square wave voltammetry (SWV) was employed to investigate the electrochemical behavior of MP. The factors affecting the performance of the proposed sensor were also optimized. The sensor makes full use of the high conductivity of hydroxyl functionalized IL and the superior electrocatalytic activity of ZIF-67, exhibiting excellent selectivity and stability. Under the optimal conditions, the IL-ZIF-67/GCE showed a good linear relationship for MP in the range of 1–20 ng l−1, and the detection limit was as low as 0.5 ng l−1 (S/N = 3). The sensor was applied for the detection of MP in river water samples, and the sample recoveries ranged from 96.6% to 101.2%.

Hierarchical nitrogen-doped holey graphene as sensitive electrochemical sensor for methyl parathion detection

Nitrogen-doped HG featuring a hierarchical macro- and nanoporous 3-D architecture with high pyrrolic-N content is a promising candidate for the construction of sensitive graphene-based electrochemical sensors for environmental and bioanalytical applications. • N-doped HG featuring a hierarchical macro- and nanoporous 3-D architecture for determination of MP was fabricated. • Pyrrolic-N in N-HG played a key role in enhanced electrocatalysis. • First principle calculations indicated that pyrrolic-N exhibited the strongest MP adsorption. • N-HG with a high pyrrolic-N content exhibited excellent sensing performance. • Ultra-low detection and excellent recovery in case of real samples were achieved. The determination of organophosphorus pesticide (OPS) residues is of great importance in reducing environmental pollution and ensuring food safety. A high-performance nitrogen-doped holey graphene (N-HG) electrochemical sensor for determination of methyl parathion (MP; one of the most commonly used OPS) based on a hierarchical macro- and nanoporous 3-D architecture has been successfully developed. The influence of various N-configurations on electron transfer kinetics and the sensing performance of the N-HG modified electrode was investigated systematically through combined practical and theoretical studies. Three N-bonding configurations were investigated in N-HG, namely, pyridinic N, pyrrolic N, and graphitic N. It was found that N-HG with a high pyrrolic-N content exhibited the largest electron transfer rate and the best sensing performance (ultralow detection limits: 3.5 pg·ml −1 ; wide linear range: 1 ng ml −1 –150 μg·ml −1 ), indicating that pyrrolic-N in the N-HG played a critical role in the electrochemical process and in enhanced electrocatalysis, as confirmed by first-principle calculations. Furthermore, the N-HG based sensor exhibited excellent selectivity and freedom from interference, good accuracy and satisfactory recoveries for real samples, confirming N-HG based electrochemical sensors have great scope for applications in environmental analysis and bio-sensing.

Graphene oxide@Ce-doped TiO2 nanoparticles as electrocatalyst materials for voltammetric detection of hazardous methyl parathion.

Asensitive voltammetric sensor has been developed for hazardous methyl parathion detection (MP) using graphene oxide@Ce-doped TiO2 nanoparticle (GO@Ce-doped TiO2 NP) electrocatalyst. The GO@Ce-doped TiO2 NPs were prepared through the sol-gel method and characterized by various physicochemical and electrochemical techniques. The GO@Ce-doped TiO2 NP-modified glassy carbon electrode (GCE) addresses excellent electrocatalytic activity towards MP detection for environmental safety and protection. The developed strategy of GO@Ce-doped TiO2 NPs at GCE surfaces for MP detection achieved excellent sensitivity (2.359μA μM-1 cm-2) and a low detection limit (LOD) 0.0016μM with a wide linear range (0.002 to 48.327μM). Moreover, the fabricated sensor shows high selectivity and long-term stability towards MP detection; this significant electrode further paves the way for real-time monitoring of environmental quantitative samples with satisfying recoveries.

Nanostructured β‐tricalcium Phosphate (Ca3(PO4)2 Based Electrochemical Sensor for Detection of Methyl Parathion and Mercury (II) Ions

In this work, we have fabricated a new electrochemical sensor based on β‐tricalcium phosphate (Ca3(PO4)2) nanoparticles (NPs) modified glassy carbon electrode (GCE) for the selective nonenzymatic determination of methyl parathion and mercury (II) ions independently. β‐tricalcium phosphate (β‐TCP) NPs were prepared by chemical precipitation method and structural and morphological properties were investigated by XRD, FTIR, and SEM. The electrochemical behavior of MP and mercury (Hg2+) ions were investigated by cyclic voltammetry (CV) and square wave voltammetry (SWV) techniques using β‐TCP/GCE. The modified electrode exhibited excellent electrocatalytic activity towards both the MP and Hg over a wide linear range from 0.15 to 141 μM and 1–381 µM with the lowest detection limits of 88 and 136.4 nM respectively. The sensor has high selectivity towards MP and Hg in the presence of major interfering compounds such as 3-nitrophenol, 4-nitrophenol, 4-aminophenol, catechol, hydroquinone and heavy metals such as lead, cadmium and arsenic. Applicability of the fabricated sensor for detection of MP and Hg (II) ions has been tested in tap water by standard addition method.

Ultrasonic-assisted preparation of halloysite nanotubes/zirconia/carbon black nanocomposite for the highly sensitive determination of methyl parathion

Herein, a cost-effective and scalable ultrasound assisted approach was proposed to prepare the nanocomposite of halloysite nanotubes/zirconia/carbon black (Hal/ZrO2/CB), which was used to fabricate a novel electrochemical sensor for the highly sensitive determination of methyl parathion (MP). In the Hal/ZrO2/CB nanocomposite, Hal with large specific surface area and numerous active sites could enhance the adsorption capacity and accelerate the redox reaction of MP; ZrO2 nanoparticles with high affinity toward the phosphate group could contribute to good recognition performance for MP; CB nanoparticles with good dispersibility formed an interconnected pearl-chain-like conductive network. Benefitting from the synergistic effect of the three components, the Hal/ZrO2/CB/GCE (glassy carbon electrode) sensor showed a remarkably low detection limit of 5.23 nM in a good linear MP detection range of 0.01–10 μM. The Hal/ZrO2/CB/GCE sensor possessed a pretty decent practicality with satisfactory RSD and recovery results for the determination of MP in peach, pear, and apple juices. Therefore, the Hal/ZrO2/CB/GCE sensor has important implication on the quite sensitive detection of MP.

Fabrication of dendritic nanoporous gold via a two-step amperometric approach: Application for electrochemical detection of methyl parathion in river water samples

In this work, nanoporous gold (NPG) was prepared according to three different approaches, such as (i) anodization-electrochemical reduction (A-ECR, NPGA), (ii) dynamic hydrogen bubble template (DHBT, NPGB), and (iii) the combination of both methods (NPGA+B). Field-emission scanning electron microscopy (FE-SEM) and cyclic voltammetry (CV) were used to investigate the structural morphology and the electrochemical behavior of the fabricated materials. The NPGA+B electrode showed a large amount of surface defects and/or edges, greater electrochemical surface area (2.5 cm2), and increased roughness factor (35.4).Such outstanding features of the NPGA+B platform were demonstrated by the sensitive detection of methyl parathion (MP) in river water samples. CV results indicated nearly 25-fold, 6-fold, and 2.5-fold higher sensitivity for NPGA+B compared to that of bare Au, NPGA, and NPGB, respectively. Differential pulse voltammetry (DPV) results show a linear behavior in the MP concentration range of 5–50 ng mL−1 with a limit of detection (LOD) of 0.6 ng mL−1 and limit of quantification (LOQ) of 2.0 ng mL−1. Besides, the NPGA+B sensor also revealed excellent selectivity towards MP detection in the presence of other interfering molecules or ions, reproducibility, and repeatability.

Magnetic Fe3O4@SiO2@β-cyclodextrin for solid phase extraction of methyl parathion and fenthion in lettuce samples.

In this study, magnetic Fe3O4@SiO2@β-cyclodextrin copolymerized microparticles were synthesized and applied for the extraction of methyl parathion and fenthion in lettuce samples followed by HPLC-UV detection. The magnetic β-cyclodextrin copolymerized microparticles were prepared by dispersion polymerization with acryloyl β-cyclodextrin as the functional monomer and ethylene glycol dimethyacrylate as the crosslinker. The composite magnetic microparticles were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, magnetic measurement, and thermogravimetric analysis, and used as the adsorbent of magnetic solid-phase extraction (MSPE) for methyl parathion and fenthion. The extraction conditions including sample pH and ionic strength, desorption solvent type and volume, and adsorption and desorption times were optimized. Under the optimal extraction conditions, an MSPE-HPLC-UV method was developed for the detection of methyl parathion and fenthion in lettuce. Wide linear ranges of 1.0-200 μg kg-1 (R2 = 0.9998) for methyl parathion and 1.5-200 μg kg-1 (R2 = 0.9978) for fenthion were obtained and the limits of detection were 0.3 μg kg-1 for methyl parathion and 0.5 μg kg-1 for fenthion in lettuce, respectively. The proposed method was applied for the determination of methyl parathion and fenthion in lettuce with satisfactory recoveries between 89.2-101.2%, and relative standard deviations were less than 9.1%. Thus, the MSPE-HPLC-UV method has high accuracy and sensitivity for the analysis of methyl parathion and fenthion in lettuce samples.

Sensitive Detection of Methyl Parathion in Human Urine Using Carboxyl-Group Functionalized Carbon Nanotubes/Carbon Paper-Based Electrochemical Sensor

Sensitive Detection of Methyl Parathion in Human Urine Using Carboxyl-Group Functionalized Carbon Nanotubes/Carbon Paper-Based Electrochemical Sensor

Purification and immobilization of His-tagged organophosphohydrolase on yolk−shell Co/C@SiO2@Ni/C nanoparticles for cascade degradation and detection of organophosphates

The synthesis or decomposition of complex substances through the combination of metals and enzymes is desirable but still a huge challenge. A kind of yolk-shell structured Co/C@SiO2@Ni/C nanocomposites were prepared by the polyhedral ZIF-67@SiO2 composite as a precursor through the extended stöber method and subsequent carbonization treatment. The SiO2 as an intermediate protective layer stabilized the morphology and structure of the carbonized products. The metallic nickel nanoparticles were uniformly distributed on the surface of Co/C@SiO2@Ni/C for highly specific absorption of His-tagged organophosphohydrolase (OpdA) from cell lysates via affinity, and therefore an integrated nanocatalyst (INC) named OpdA@Co/C@SiO2@Ni/C was successfully prepared. The prepared INC was applied to achieve a one-pot chemoenzymatic cascade degradation of organophosphates (OPs) to p-aminophenol (PAP) within 30 min. In addition, the INC proved to be a simple and high-sensitivity nanocatalyst for the detection of methyl-parathion with a low limit of detection (0.30 μM). The INC exhibited improved pH stability, thermal stability, SDS resistance, and storage stability compared to that of free enzymes. When OpdA@Co/C@SiO2@Ni/C was reused for 7 cycles, the cascade degradation efficiency of methyl-parathion could retain more than 60 %. This study provides a strategy for constructing a multifunctional nanocatalyst, and further demonstrated its potential in biocatalysis, accurate detection of OPs and remediation of environmental pollution.

Novel graphene electrochemical transistor with ZrO2/rGO nanocomposites functionalized gate electrode for ultrasensitive recognition of methyl parathion

A novel graphene electrochemical transistor (GECT) based on zirconia/reduced graphene oxide (ZrO2/rGO) nanocomposites functionalized gate electrode and graphene as channel was successfully designed and fabricated for highly sensitive detection of methyl parathion (MP). ZrO2/rGO nanocomposites were co-electrodeposited on a glassy carbon electrode considering the special affinity of ZrO2 toward phosphate groups and high specific surface area of rGO. The sensing mechanism is attributed to the change of effective gate voltage applied to GECT induced by the electrochemical reactions of MP at the functionalized gate electrode, thus tuning the channel carrier concentration and the channel current. Due to the excellent electrocatalytic activity of ZrO2/rGO on the gate and the high carrier mobility of graphene in the channel, the developed sensor exhibited excellent sensing performances with ultra-low detection limit (10 pg/mL) and ultra-wide linear range from 10 pg/mL to 10 μg/mL, which especially stand out of the reported devices. The GECT sensor also showed good selectivity toward usual interferents and strong practicality through testing MP in Chinese cabbage samples. The developed GECT devices provided not only the novel platform for pesticide detection with high sensitivity but the new method of enhancing the sensing performance through specifically functionalized gate electrode.

MWCNT/zirconia porous composite applied as electrochemical sensor for determination of methyl parathion

Abstract A selective, sensitive, quickly responsive and simple sensor for methyl parathion (MP) detection was developed using a composite based on a nearly 45% by weight of highly dispersed multiwalled carbon nanotubes (MWCNT) in a zirconia matrix, synthesized by sol-gel method. The composite MWCNT/zirconia showed a mesoporous nature, presenting a high surface area of 135 m2 g−1, where morphology and texture of MWCNT were preserved. The modified carbon paste electrode, obtained with this porous composite, presented an electroactive area of 7.4 mm2, showing a good response for MP detection. The electrochemical parameters for MP were obtained by differential pulse voltammetry (DPV) with detection limit of 9.0 × 10−9 mol L−1 and sensitivity of 1.475 μA μmol−1 L in a linear interval of 19.9 × 10−6 at 176.8 × 10−6 mol L−1. The electrode presented good selectivity in the presence of different interferences; it also showed good repeatability with RDS 0.91% for 13 cycles and reproducibility with RSD 14.2% in measurements. The sensing platform was tested in an ethanolic soybean extract with addition of methyl parathion at concentrations of 160; 180 and 200 × 10−6 mol L−1. The recoveries varied from 102 to 113%, and the relative standard deviation was 5.2%. The developed sensor demonstrated to be adequate for its utilization in the determination of methyl parathion with the purpose to ensure food safety.

Electrochemical detection of methyl parathion via a novel biosensor tailored on highly biocompatible electrochemically reduced graphene oxide-chitosan-hemoglobin coatings

A quick electrochemical sensing tool by utilizing novel bioelectrode based on redox active protein hemoglobin (Hb) has been offered here for the determination of methylparathion (MP). The bioelectrode has been designed by immobilizing Hb on electrochemically reduced graphene oxide-chitosan (ERGO-CS/Hb/FTO) based biocompatible coatings. Fourier transform-infrared analyses (FTIR), field emission scanning electron microscopy (FESEM), UV-visible and electrochemical characterization reveal the successful grafting of ERGO-CS/Hb/FTO. A detailed impedimetric analysis shows low charge transfer resistance (RCT) and solution resistance (Rs) for the fabricated biosensor, thus pointing towards improved electrochemical performance and sensitivity. In-depth elucidation of redox analysis has been presented in terms of surface concentration of redox moiety (2.92×10-9molcm-2) and heterogeneous electron transfer rate constant (0.0032s-1) which indicate enhanced surface coverage and better charge transfer properties of the proposed electrochemical biosensor. The sensor is equipped with a low limit of detection of 79.77nM and a high sensitivity of 45.77Acm-2μM-1 with excellent reproducibility. The modified biosensor also offered its credibility towards detection of MP in vegetable samples with recovery (%) ranging from 94% to 101%. The designed biosensor hereby, evolves as a promising approach for the recognition of MP.

Highly sensitive methyl parathion sensor based on Au-ZrO2 nanocomposites modified graphene electrochemical transistor

The excessive use of pesticides does great harm to environment and human health, a high performance sensor is urgently needed for the management of pesticides contamination. Herein, a novel graphene electrochemical transistor (GECT) for the detection of methyl parathion (MP) was successfully fabricated for the first time. A single layer of graphene was covered between the source and drain electrodes by the wet transfer method to act as channel for the transistor. Au-ZrO2 nanocomposites were electrodeposited at graphene channel of the device, considering the special affinity of ZrO2 nanoparticles toward phosphate group and electrocatalytic ability of Au nanoparticles. The sensing mechanism was attributed to the change of carrier concentration in channel induced by the electrochemical reaction of MP at the graphene channel, which built up the mathematic relationship between the change of channel current and the concentration of MP. Different modified materials and electrodeposition conditions were compared and optimized. Due to the high carrier mobility of graphene and excellent catalytic performance of Au-ZrO2 nanocomposites in the channel, the developed sensor showed a limit of detection as low as 0.1 ng/mL and ultra-wide linear range from 0.4 ng/mL to 7 μg/mL, which are comparable or superior to those using the large-scale instruments. Meanwhile, the device exhibited good selectivity toward usual interferents and high accuracy for detection of MP in Chinese cabbage samples, demonstrating the promising practicality of the devices. It is expected that GECT can act as a desirable transducer platform for highly sensitive and selective detection of pesticides.

Methyl Parathion Detection Using SnS2/N, S–Co-Doped Reduced Graphene Oxide Nanocomposite

The rapid and ultralow detection of toxic organophosphate chemicals is a well-known, important step to reduce adverse health issues and yet also remains challenging. Here, we show electrochemical d...

A smart-phone based ratiometric nanoprobe for label-free detection of methyl parathion

The widespread use of pesticides in pest management has boosted the demands for developing highly sensitive probes for on-site monitoring. Herein we presented a sensitive enzyme-free ratiometric probe for determination of methyl parathion (MP), as an organophosphate pesticide using TGA-capped CdTe QDs and carbon dots (CDs). Unlike previous methods in which hydrolysis product of MP is instrumental in the response of the sensors, here, self-assembly of cetyltrimethylammonium bromide (CTAB) on the surface of non-modified yellow-emissive CdTe QDs facilitates the quenching of CTAB-QDs upon addition of MP while the fluorescence intensity of CDs remains constant. Using a smartphone, the ratiometric probe shows visual emission color changes from orange-peach into pink, purple, weak blue, and dark blue, which is highly appropriate for quantitative detection of MP based on the hue-saturation-lightness color model. A wide linear range from 0.001 μg.mL−1 to 10 μg. mL−1 MP with a low limit of detection of 1.2 ng. mL−1 (S/N = 3) were obtained under optimized condition. Furthermore, with high sensitivity and selectivity, this platform has the capability to detect MP in rice and tap water samples with desired results.

Easy-to-use and reliable absorbance-based MPH-GST biosensor for the detection of methyl parathion pesticide

Due to high contamination of organophosphate (OP) insecticides in agricultural products and the environment, efficient and convenient devices for their monitoring are necessary. Here, a simple, inexpensive, efficient, and easy-to-use absorbance-based biosensor was fabricated utilizing recombinant methyl parathion hydrolase fused with glutathione-S-transferase (MPH-GST), covalently immobilized onto a chitosan film-coated polystyrene microplate, for the detection of methyl parathion (MP) as a representative of OPs. Having been connected to the transducer system designed to work through an Arduino microcontroller, the biosensor could detect MP as efficiently as the conventional methods, with the detection limit of 0.1 μM, the lowest value ever reported for this method. It was stable at 25 °C for 30 days, could function 100 rounds repetitively, and yielded high recovery with real samples. Hence, this simply designed MPH-GST biosensor could be an easy and inexpensive alternative for efficient OP screening at site to help control its contamination.

Flexible paper-based SERS substrate strategy for rapid detection of methyl parathion on the surface of fruit.

Herein, we reported a simple, flexible and sensitive surface-enhanced Raman scattering (SERS) substrate to detect methyl parathion residues in real life. The substrate was fabricated by filter paper and gold nanoparticles (Au NPs) with excellent reproducibility and stability. First, Au NPs were synthesized by the seed mediated growth method and assembled to the filter paper through immersion. The Raman probe molecule 4-MBA was used to evaluate performance of the substrate for an optimized signal using a portable Raman spectrometer coupled with 785nm laser. Then, the paper-based substrate was applied to detect methyl parathion standard solution whose detection limit was down to 0.011μg/cm2, and the linear range was between 0.018μg/cm2 and 0.354μg/cm2. Afterwards, actual sample (apple) spiked with methyl parathion was taken to verify the practicality of the substrate by a simple way of "press-peel off". The recovery rate was ranged from 94.09% to 98.72%, indicating that this method is reliable in actual sample detection without complicated pretreatment steps. This work demonstrates that the flexible paper-based substrate combined with portable Raman instruments can be potentially applied to on-site detection of hazardous substances in the field of food safety.