Tomato Residues Research Articles

A highly sensitive β-AKBA-Ag-based fluorescent “turn off” chemosensor for rapid detection of abamectin in tomatoes

Abstract This study presents the synthesis of a sensitive AKBA-Based fluorescent “Turn off” chemosensor for rapid detection of abamectin residues in tomatoes. Silver nanoparticles were synthesized by using 3-O-acetyl-11-keto-β-boswellic acid (β-AKBA) by chemical reduction method. The characterization of AKBA-AgNPs was performed by UV–vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM). The average particle size of NPs was found to be 46.2 ± 2 nm with lumps of macro-sized particles. TEM data further revealed that nanoparticles were polydispersed and spherical in shape and also show good stability at high temperatures and pH. The biosensing properties of nanoparticles were studied for the detection of abamectin residues in tomato samples. Abamectin a natural product derived from the bacterium Streptomyces avermitilis is effective against a wide range of pests. In sensing protocol 67 organic tomato samples were segregated into 34 (safe group, without a spray of abamectin) and 33 samples (as an unsafe group, sprayed with abamectin insecticide solution). Emission spectra of these sample solutions were measured in the wavelength range of 450–530 nm, excitation wavelength was fixed at 488 nm. The effect of minor wavelength variation for the discrimination and classification of the two groups was investigated by applying two chemometric methods including partial least square discriminant analysis and principal component analysis with projection. The mechanism of its interaction between the AKBA-Ag NPs and abamectin residue was also established through UV/visible, FTIR, and TEM microscopy. This newly synthesized nanoparticle was found to have excellent stability at variables, i.e., temperature, storage period, salt concentration, and pH. Therefore, the synthesized Ag NPs are potential candidates for biosensing applications against abamectin.

Bioanalytical Method: Determining pesticide residues in tomatoes and mushrooms by a bioactive membrane-based sensor, enzyme inhibition and UV-Vis Spectrophotometry

Bioanalytical Method: Determining pesticide residues in tomatoes and mushrooms by a bioactive membrane-based sensor, enzyme inhibition and UV-Vis Spectrophotometry

Tailor-made green composts with suppressive properties against tracheofusariosis of wild rocket (Diplotaxis tenuifolia): Useful option for sustainable circular horticulture

Intensive cultivation systems of wild rocket (Diplotaxis tenuifolia) are threatened by the outbreak of tracheofusariosis caused by the soil-borne fungal pathogen Fusarium oxysporum f. sp. raphani. The disease is difficult to eradicate by curative methods due to the endophytic progression of the pathogen. Suppressive composts can help to prevent this adversity by providing organic matter carrying chemical and biological components that can directly and/or indirectly interfere with the plant-pathogen system. In this study, a collection of seven promising composts from different selected green feedstocks were investigated for their suppressive properties towards wild rocket Fusarium wilting. In planta assays identified two composts, obtained from olive tree pruning + plant and tomato residues, and from olive waste + straw + wool residues, with the highest levels of suppressiveness, influenced by both application dose and plant development stage. These active composts showed overlapping 13C NMR profiles as in vivo suppressiveness, being positively correlated with the organic aliphatic alkyl, O-Aryl and carboxyl C fractions and subsequently with the hydrophobic index and alkyl ratio, and negatively with the lignin ratio. On the contrary, although biotic compost components showed antifungal effects, biological properties did not correlate with in planta wilting suppression. Consistently, reflectance spectroscopy in the Vis-NIR-SWIR highlighted the clustering of samples depending on their feedstock and chemical composition. The results allow the hypothesis of a plant-mediated suppression mechanism. The composting of crop residues improves the circularity of horticulture and makes it possible to produce, from selected matrices, tailored compost towards the sustainable cultivation of wild rocket.

Analysis of Consumers’ Perception of Insecticidal Preservatives and Its Residues in Cucumber and Tomato from Selected Markets in Port Harcourt

A market survey involving 100 fruit sellers/consumers who were randomly selected in Fruit garden, Rumuokoro, Mile 3 and Oil Mill markets was conducted to examine their awareness of chemical preservatives, residual and dietary effects on their body. The study utilizes primary data which was collected through the use of questionnaire from the respondents and personal observation by the researchers. A semi structured standardized questionnaire was administered to the respondents to gather information about their socio demographic characteristics, knowledge, and attitude of the traders/consumers on nutrition and food preservation. Only 150 copies of the questionnaire were distributed by the researcher with the help of researches assistance. Data were analyzed using descriptive statistics such as frequency distributions, percentages, mean score and correlation coefficient. In this survey, the seller/consumers above 35 years old consumes more of the fruits (35%) and those of 70kg weight recorded above 52%. Only 29% of respondents are aware that fruits bought are usually preserved with banned chemicals (gammalin 20, carbide etc.) by the traders. The hazard index recorded by tomato (1.2 – 1.3) and cucumber (1.8 – 2.2) was high in both markets under study. The consumption of tomato and cucumber is correlated positively with Weight (0.091) (0.019), Height (0.086) (0.178) and Body mass index (0.016) (0.043).

Tomato Residue Management from a Biorefinery Perspective and towards a Circular Economy.

The tomato industry is a relevant socio-economic activity in the European Union, while it generates a large variety of residues. Tomatoes unfit for consumption, tomato peels, seeds, industrial pomace, and plants are examples of residues of this industry. Commonly, some of the residues can be left in the field, composted, used for animal feeding, or valorized through anaerobic digestion. However, more economic value can be attributed to these residues if a biorefinery approach is applied. Indeed, many value-added compounds can be obtained by the integration of different processes while closing the carbon and nutrient loops. The extraction of bioactive compounds followed by anaerobic digestion and composting seems to be a viable proposal for a biorefinery approach. Thus, this study aims to review the biorefinery strategies for valorizing tomato residues, highlighting the main processes proposed. The recovery of lycopene, β-carotene, and phenolic compounds has been widely studied at the lab scale, while energy recovery has already been applied at the industrial scale. Although techno-economic analysis is scarce for tomato residue valorization processes, positive net present values (NPV) and low payback times (PBT) have been reported in the literature. Thus, more work comparing multiple extraction technologies and biorefinery strategies coupled with economic and environmental assessment should be performed to select the most promising management route for tomato residues.

Study of a new matrix certified reference material for simultaneous measurement of two plant growth regulators residues in tomato

A new matrix certified reference material (CRM) was developed for analysis of chlormequat chloride (CCC) and 2,4-dichlorophenoxyacetic acid (2,4-D) residues in tomato pulp. A tomato pulp CRM candidate with the same matrix composition and similar residues concentration level to the real sample was prepared by means of adding drugs. Liquid chromatography tandem isotope dilution mass spectrometry (ID-LC-MS/MS) was established to accurately determinate CCC and 2,4-D residues in tomato pulp CRM candidates. The characterization of mass fractions of CCC and 2,4-D in tomato pulp were conducted by 8 laboratories. The certified values for CCC and 2,4-D were assigned to be 4.1 mg/kg and 1.9 mg/kg, with expanded uncertainties of 0.4 mg/kg and 0.3 mg/kg at a confidence level of 95 % (coverage factor k = 2), respectively. The results of homogeneity testing show that the CRM was homogeneous for CCC and 2,4-D between and within bottles. The stability monitoring results indicated that the CRM could be stable for 14 months at −20 °C storage temperature and for 9 days under 30 °C transportation condition. The developed CRM has been authorized and numbered as GBW(E)100933. It would be conductive to method validation in the residues monitoring of CCC and 2,4-D in fruits and vegetable products.

Optimization of QuEChERS method for determination of pesticide residues in vegetables and health risk assessment.

The present study focused on the optimization of the QuEChERS extraction method for the determination of 61 pesticide residues and associated health risk assessment in 144 samples of commonly consumed vegetables, viz., eggplant, cabbage, green chilli, okra, and tomato. The samples were collected between January and April 2022 from three different districts within Gujarat, India. The QuEChERS method was optimized and utilized for the extraction of samples. The samples were analyzed by UHPLC-q-TOF/MS and GC-MS/MS. The modified QuEChERS method was successfully validated, and the obtained results were satisfactory as per the 2021 SANTE guidelines. The residue analysis of the vegetable samples showed that about 4% of total samples contained single pesticide residues. Pesticide residues below the quantitation limit (BQL) were observed in eggplant, cabbage, and okra samples. In total, 15.62% (n = 5) samples of green chilli showed the presence of pesticides such as azoxystrobin, bifenthrin, cypermethrin, fenpropathrin, and propargite whereas 3% (n = 1) tomato samples contained cyfluthrin. In total, 97.22% of the samples had residues that were below the European Union Maximum Residue Limit (EU MRL). Two samples of green chilli had pesticide residues above EU MRL. The Hazard Index (HI) and Hazard Quotient (HQ) were used to assess the health risks associated with green chilli and tomato consumption. The HI and HQ values for adolescents and adults were found to be less than 1. The modified QuEChERS method was found to be easy and effective and can be implemented for routine sample analysis. The study revealed the presence of pesticide residues in tomato and green chilli samples. Further, the outcome provided information pertaining to current pesticide status, concluding that consumption of these commodities is unlikely to pose any health risk, though long-term monitoring studies focusing on dietary health risk assessment must be initiated.

The Biogas Production Potential and Community Structure Characteristics of the Co-Digestion of Dairy Manure and Tomato Residues

Anaerobic digestion is an important means to turn agricultural waste into resources and an important way to address the challenges in treating vegetable residues in China. In this study, the co-digestion of dairy manure with tomato residue was investigated to clarify the effect of the total solids (TS) of the digestion substrate on methane’s production and mechanism using the self-made anaerobic digestion device. The results showed that all treatments could rapidly ferment methane and that the daily methane production showed a trend of increasing first and then decreasing. The optimal concentrations of the digestion substrate for liquid anaerobic digestion (L-AD), hemi-solid-state anaerobic digestion (HSS-AD), and solid-state anaerobic digestion (SS-AD) were 10%, 18%, and 25%, respectively. Compared with SS-AD and HSS-AD, L-AD gas production peaked 3–6 days earlier. Treatment TS25 had the best cumulative methane production, reaching 117.4 mL/g VS. However, treatment TS6 had acid accumulation and a very unstable system. The cumulative methane production of SS-AD was higher than that of HSS-AD and L-AD. Firmicutes and Bacteroidetes were the dominant flora, and Methanoculleus, Methanosarcina, and Methanobrevibacter were the main archaeal groups. The TS significantly changed the microbial community composition of the digestion system, especially the low TS treatment. The results presented herein indicated that TS significantly changed the bacterial and archaeal community composition of the digestion system, and thus with the increase in TS from 6% to 25%, the methane yield increased.

Rapid and sensitive quantitation of amitraz in orange, tomato, and eggplant samples using immunochromatographic assay

Amitraz (AMT) is a broad-spectrum formamidine insecticide and acaricide. In this study, we produced an anti-AMT monoclonal antibody (mAb) with high performance. The half-maximal inhibitory concentration of the anti-AMT mAb was 4.418 ng/mL, the cross reactivity with other insecticides was negligible, and an affinity constant was 2.06 × 109 mmol/L. Additionally, we developed an immunochromatographic assay for the rapid detection of AMT residues in oranges, tomatoes, and eggplants. The cut-off values were 2000 μg/kg in oranges and tomato samples and 1000 μg/kg in eggplant samples and the calculated limits of detection were 14.521 μg/kg, 6.281 μg/kg, and 3.518 μg/kg in oranges, tomatoes, and eggplants, respectively, meeting the detection requirements for AMT in fruits and vegetables. The recovery rates ranged between 95.8 % and 105.2 %, consistent with the recovery rates obtained via LC-MS/MS. Our developed immunochromatographic assay can effectively, accurately, and rapidly determine AMT residues in oranges, tomatoes, and eggplants.

Residue dissipation kinetics, safety evaluation and decontamination of Deltamethrin in tomato and the soil

Tomato powdery mildew, fruit rot, and twig blight are all managed with Deltamethrin. Its residues could still be present in the crops, posing a health risk. The pesticide residue analysis, dissipation rate, and safety assessments were thus examined in green tomatoes. The analytical method for residue analysis was validated according to international standards. Tomato fruits and soil were used to study the dissipation of Deltamethrin 100 EC (11% w/w) at 12.5 g a.i ha−1 for the recommended dose (RD) and 25.0 g a.i ha−1 for the double of the recommended dose (DD). Ethyl acetate was used to extract residues from tomato fruit, and PSA and magnesium sulphate were used for cleanup.The fruits had recoveries ranging from 83% to 93% and the soil sample from 81.67% to 89.6%, with the limit of detection (LOQ) estimated at 0.01 mg kg−1. The matrix effect (ME) was calculated to be less than 20% for the tomato fruits and the soil.Half-lives for RD and DD were 1.95 and 1.84 days, respectively. All sampling days for both doses had dietary exposures of residues below the maximum permissible intake (MPI) of 0.16 mg person−1 day−1. The most effective method of decontaminating tomato residue containing Deltamethrin is blanching.

Surveillance of pesticide residues in tomato and eggplant and assessment of acute and chronic health risks to the consumers in Pakistan.

Pesticide application has become a mandatory requirement of the modern agricultural system, resulting in the objectionable levels of pesticide residues in the treated food commodities and posing health threats to the consumers. This study aimed at optimization and validation of an analytical method which can be reliably applied for routine monitoring of the selected eighteen widely reported pesticides in tomato and eggplant. The principle of quick, easy, cheap, effective, rugged, and safe, i.e., QuEChERS, involving the acetate-buffered extraction followed by cleanup using the primary secondary amines (PSA) was employed. The analytical method was validated at three spiking levels (0.05, 0.01, 0.005mg/kg) using gas chromatograph-micro electron capture detector (GC-µECD). Gas chromatograph-mass spectrometric detector (GC-MSD) was also used for confirmation and quantification using selective ion monitoring (SIM) mode. The method was applied on fresh samples of tomato (n = 33) and eggplant (n = 27) collected from local markets of Khyber Pakhtunkhwa, Pakistan, in the crop season 2020-2021. Twenty-five (76%) tomato samples and fifteen (56%) eggplant samples were found positive for one or more pesticides. Though the chronic and acute health risk assessments indicate that both of these vegetables are unlikely to pose any unacceptable health threat to their consumers, yet the risks from regular intake of pesticides-contaminated food commodities should be regularly addressed for possible protection of the public health and assurance of safe and consistent agro-trade, alike.

Characterization and antifungal properties against wood decaying fungi of hydrothermal liquefaction liquids from spent mushroom substrate and tomato residues

This study aimed to investigate the potential of converting bio-based residues from industrial production of mushrooms and tomatoes into more valuable chemicals with antifungal properties using hydrothermal liquefaction (HTL). Liquid fractions were obtained from HTL of spent substrate of Agaricus bisporus (Lange) Imbach and Pleurotus ostreatus (jacq.) P. kumm., recomposted Agaricus bisporus spent substrate, and tomato residues. The quantitative 1H NMR spectroscopy analysis revealed that the HTL liquids of all residues contained antifungal constituents like phenols and organic acids. The HTL liquids at dilutions of 10 % were able to inhibit the fungi by over 80 %. Interestingly, the fungus P. ostreatus showed tolerance to these constituents as its growth was promoted at the lowest concentration of all the HTL liquids. The HTL liquids had lower ecotoxicity than the commercial wood preservative. These results suggest that the tested residues could be a promising source of preservative chemical constituents for the wood industry.

Simultaneous determination of enantiomeric residues of flutriafol, hexaconazole and diniconazole in fruits and vegetables on a bridged cyclodextrin-based column by HPLC

The new type of bis-triazolyl bridged cyclodextrin-based stationary phase (BCDP) was prepared through “Click reaction”. BCDP had high selectivity for triazoles and was used for the simultaneous fast separation and determination of enantiomeric residues (flutriafol, hexaconazole and diniconazole) in fruits and vegetables by high-performance liquid chromatography (HPLC). The QuEChERS method assisted by magnetic nanoparticles was used for sample pretreatment, and then a gradient elution was carried out by using MeOH-H2O as the mobile phase on BCDP to achieve rapid resolution of the triazole enantiomers within 25 min. After condition optimization, simultaneous baseline separations of the six enantiomers were achieved with resolutions of 1.54 (flutriafol), 2.27 (hexaconazole) and 1.97 (diniconazole). A new HPLC quantification method of the six enantiomeric residues in apples, tomatoes and cucumbers was established by an internal standard with a photo-diode array (PDA) detector at 210 nm. The results showed that the excellent linear relationships of all triazole enantiomers were observed in the concentration range of 0.5–50 mg L-1 (R2 = 0.9986–0.9999). The average recoveries of enantiomers in fruits and vegetables were from 91.95 % to 109.92 % with RSDs of 0.97 %–1.32 % for intraday and 1.30 %–3.03 % for interday. The limits of detection (LODs, S/N = 3) and limits of quantitation (LOQs, S/N = 10) of all enantiomers were less than 0.03 mg kg−1 and 0.10 mg kg−1, respectively. BCDP had high selectivity for triazole due to its synergistic inclusion with triazoles and advantage in fast and simultaneous separation of multiple triazole enantiomers, which could save analysis time and reduce solvent consumption. BCDP was a new separation material for the scientific evaluation of chiral pesticides in the food safety analysis.

Lateral flow immunoassay based on gold nanoparticles for rapid and sensitive detection of zoxamide in grape, tomato and cucumber samples.

In the study, we discovered zoxamide hapten (ZOX-hapten) by introducing a carboxyl extension chain, combined it with protein to make a complete antigen to immunize mice, and generated a monoclonal antibody (mAb) against ZOX. To identify ZOX residues in grape, tomato, and cucumber samples, we used our anti-ZOX mAb to develop a lateral flow immunoassay (LFIA) strip. In grape, tomato, and cucumber samples, the calculated detection limit of the LFIA strip in grape, tomato and cucumber samples was 3.44, 4.78 and 3.53ng/g, respectively. Using the LFIA strip, the recovery rate from grape samples was 96.4-106.8%, and that from tomato samples was 98.4-107.5%, while the recovery from cucumber samples was 99.4-111.3%. These results showed that our LFIA strip could be expected to achieve rapid screening of ZOX residues in fruits and vegetables.

Assessment of consumer’s knowledge and practices on pesticide residues reduction in tomatoes in Mvomero, Morogoro region, Tanzania

Pesticides are important components of agricultural production but the consumption of crops treated with pesticides, even in small quantities, can accumulate in the human body and cause health problems. Therefore, consumers’ knowledge and practices on reduction of these residues is essential however, there is scant of information on consumers’ knowledge and practices on pesticide residues reduction in tomatoes in Tanzania. A cross-sectional study was conducted at Mvomero District in Morogoro region among 280 randomly selected consumers. Questionnaires were administered through face-to-face interviews to assess knowledge and practices on the reduction of pesticide residues in tomatoes before consumption. Data were analyzed using SPSSTM version 20 to obtain descriptive and inferential statistics. Results showed that 64.6% of respondents know that pesticides can cause health effects of which, 41% are not sure of the specific health problem with few mentioning cancers. About 80% of respondents know that tomatoes sold in the market have pesticide residues. Majority of respondents (78.9%) believe that the pesticide residues in tomatoes disappear after cooking. Seventy-five percent of respondents reported that they know methods for reducing pesticide residues of which 66.8% reported to be reducing pesticide residues by washing with water. Generally, consumer’s knowledge on health effects and practices on reduction of pesticide residues before consumption was relatively poor. Hence, there is a need for improving knowledge on reducing pesticide residues in tomatoes using cost-effective methods that are applicable at the household level. Knowledge on the health effects of pesticide residues was significantly associated with having a mobile phone, reading newspapers, and attending training on pesticides and associated health effects. Therefore, phones, radio, and newspapers may be used as effective methods for communicating health information to the public.

Immunochromatographic assay for rapid detection of flupyradifurone in grape, blueberry, and tomato samples

Flupyradifurone (FPF) is a neonicotinoid insecticide that effectively controls the spread of various pests. In this study, we established an immunochromatographic assay based on a highly specific and sensitive anti-FPF monoclonal antibody (mAb) to screen for FPF residues in grapes, blueberries, and tomatoes. The cut-off value for the immunochromatographic assay was 5 mg/kg for grapes and 10 mg/kg for blueberries and tomatoes. The calculated limit of detection of the immunochromatographic assay was 0.009 mg/kg, 0.033 mg/kg, and 0.040 mg/kg for grapes, blueberries, and tomatoes, respectively. The recovery rates of the immunochromatographic assay were 97.0–108.2 % in grape samples, 90.9–105.1 % in blueberry samples, and 94.0–103.7 % in tomato samples, and the detection results were highly consistent with LC-MS/MS results. Therefore, this immunochromatographic assay was an effective and rapid tool for screening for FPF in grapes, blueberries, and tomatoes.

A QUECHERS method for sample preparation in the analysis of pesticides in tomato

The tomato is one of the crops that is likely to be attacked by pests. The use of pesticides during its harvest has consequently increased in recent years. This use has raised concerns about the presence of chemical contaminants in food, which may have harmful effects on health. To identify and determine the presence of pesticides efficiently and reliably at any of the stages: washing, peeling and sterilization, a fast, easy, cheap, effective, robust, and safe methodology (QuEChERS) is created. Today, it is successfully implemented for the monitoring of these residues in tomato with recovery percentages and relative standard deviations according to international standards. This review analyzes the application of the QuEChERS methodology for the identification and determination of pesticides in tomato, through a review of the literature in recent years. In addition, a bibliometric analysis of the Scopus database between 2007-2021 is performed, finding that the most published areas are Chemistry and Agriculture, being China the leading country with more publications. It was concluded that in most of research, modifications are made in the methodology such as the use of dicyandiamine sludge, obtaining good results in the extraction and recovery percentages with the advantage of having a lower cost and environmental pollution.

OBTAINING ANTIOXIDANTS FROM FOOD INDUSTRY WASTE AND THEIR USE IN FATS

The food industry generates a large amount of waste and by-products of processing, which becomes a problem for the environment. Potato and onion peel, tomato seeds and peel are agro-industrial wastes of the world's main vegetable crops. However, the potential for antioxidants from them is not yet fully known. In this work, the influence of extracts obtained from these wastes on the process of inhibition of the rate of oxidation of sunflower oil was studied. Regression equations describing the process of extraction of biologically active substances from crop production waste as a result of water-ethanol extraction at a temperature of 60°C were obtained. It was established that the optimum concentration of ethanol in the water-ethanol mixture of extractants is in the range of 70–80%. Increasing the extraction time has a positive effect on the yield of extractive substances (at an interval of 2–15 hours). The kinetics of oxidation of sunflower oil by the accelerated method was studied and the antioxidant activity of the obtained antioxidants was determined, which is: for onion peel 2.29 (ie at a concentration of antioxidant 200 mg/kg oil the induction period of sunflower oil oxidation is more than doubled). For potato peels, this figure is 3.17, and for tomato peels – 1.85. All antioxidants obtained from plant waste were no less effective than butylhydroxyanisole (antioxidant activity – 1.93). The effectiveness of antioxidants varied as follows: onion peel > potato peel > butylhydroxyanisole > tomato residues. The expediency of using ascorbic acid in the course of water-alcohol extraction of antioxidants from vegetable raw materials has been proven. It has a positive effect on increasing the output of antioxidants and on extending the induction period of sunflower oil as a result of its own antioxidant properties. The existence of a synergistic effect between ascorbic acid and substances extracted from potato, onion and tomato peel has been proven, which in numerical value is 163, 126, and 180%, respectively.

Effects of Electrolyzed Reducing Water on Pesticides Reduction and Postharvest Qualities in Cherry Tomato

This study investigated the effect of electrolyzed reducing water (ERW) on the reduction of profenofos (PF) and carbendazim (CBZ) residue of cherry tomato (Solanum lycopersicum var. cerasiforme). Organic tomato were soaked with pesticides solution (PF and CBZ) at 5 mg L-1, then air dried at room temperature. Thereafter, the treated fruits were washed with ERW at different concentrations (50, 100, 250, and 500 mg L-1) for various times (10, 20, and 30 min). The result found that the removal percentages of standard profenofos and carbendazim were significantly induced with ERW 500 mg L-1 for 20 min. Wherewith, the profenofos released the substance to pyrocatechol and 4-Methylphenol (p-Cresol), and carbendazim was degraded to a N-Acetyl-2,6-diethylaniline. The removal percentage of profenofos and carbendazim residues in tomato was found to be possible to effectively reduce residues 71.54% and 80.49%, respectively. On the other hand, distilled water (DW) could achieve removal of only 21.67%. The quality of the tomato stored at 25ºC for 8 days showed that not significant changes in weight loss, firmness, total soluble solids (TSS), titratable acidity (TA), lycopene content, and visual appearance for both pesticides. Keywords: Electrolyzed reducing water, Profenofos, Carbendazim, Cherry tomato

Development of Magnetic Lateral Flow and Direct Competitive Immunoassays for Sensitive and Specific Detection of Halosulfuron-Methyl Using a Novel Hapten and Monoclonal Antibody.

Halosulfuron-methyl (HM) is widely used for the removal of noxious weeds in corn, sugarcane, wheat, rice, and tomato fields. Despite its high efficiency and low toxicity, drift to nontarget crops and leaching of its metabolites to groundwater pose potential risks. Considering the instability of HM, the pyrazole sulfonamide of HM was used to generate a hapten and antigen to raise a high-quality monoclonal antibody (Mab, designated 1A91H11) against HM. A direct competitive immunoassay (dcELISA) using Mab 1A91H11 achieved a half-maximal inhibitory concentration (IC50) of 1.5 × 10-3 mg/kg and a linear range of 0.7 × 10-3 mg/kg-10.7 × 10-3 mg/kg, which was 10 times more sensitive than a comparable indirect competitive ELISA (icELISA) and more simple to operate. A spiking recovery experiment performed in tomato and maize matrices with 0.01, 0.05, and 0.1 mg/kg HM had average recoveries within 78.9-87.9% and 103.0-107.4% and coefficients of variation from 1.1-6.8% and 2.7-6.4% in tomato and maize, respectively. In addition, a magnetic lateral flow immunoassay (MLFIA) was developed for quantitative detection of low concentrations of HM in paddy water. Compared with dcELISA, the MLFIA exhibited 3.3- to 50-fold higher sensitivity (IC50 0.21 × 10-3 mg/kg). The average recovery and RSD of the developed MLFIA ranged from 81.5 to 92.5% and 5.4 to 9.7%. The results of this study demonstrated that the developed dcELISA and MLFIA are suitable for rapid detection of HM residues in tomato and maize matrices and paddy water, respectively, with acceptable accuracy and precision.