Harnessing the Carrier Solvent Complexity of Crop Biostimulant Liquid Formulations Using Locally Available Transesterified Waste Cooking Oil: Economic Recycling, Solvent Performance, and Bioefficacy Evaluation.

Locally sourced waste cooking oil (WCO) was successfully base-catalyzed and transesterified with methanol into biodiesel to produce biostimulant (nitrobenzene) formulations and replace high-risk carrier solvents. Ideal synthesis conditions were composed of 1% NaOH, MeOH/oil molar ratio (6:1), reaction temperature (65 °C), a 3 h mixing rate, and 97-98% yields. Gas chromatography-mass spectrometry (GC-MS) analysis identified five fatty acid methyl esters (FAMEs) including palmitic, linoleic, oleic, stearic, and eicosenoic acids with high solubilization and olfactory characteristics. Using anionic and nonionic emulsifiers in conjunction with recycled biodiesel, a stable emulsifiable concentrate (NB 35% EC) was created with greater storage stability, wettability, and spreading capabilities than those of organic solvent-based ones. The highest counts of fruits per plant (35.80), flowers per plant (60.00), yield per plant (3.56 kg), and yield per hectare (143.7 quintals) were recorded in treatments with 4 mL/L biodiesel-based EC in field bioassays. In addition to having superior biosafety, FAME-based EC exhibits minimal phytotoxicity and is less harmful to aquatic creatures. It was discovered that the average cost-effectiveness was 5.49 times less expensive than solvent-based EC. In order to utilize waste oils as a locally obtained, sustainable alternative solvent with a wide solubilization range, low ecotax profile, circular economy, and high renewable carbon index, this integrative technique was expanded.

Determination of quizalofop-p-ethyl in onion: residual dissipation pattern, weed control efficiency, and food safety assessment under field conditions.

Monitoring pesticide residue levels becomes crucial to maintain quality and guarantee food safety as the consumption of onion green leaves and immature and mature bulbs (either raw or processed) rises. A field experiment was conducted for two consecutive seasons with quizalofop-p-ethyl (5% EC) at 50 and 100 g a.i. ha-1 to evaluate weed control efficiency and to determine terminal residues. Post-emergence application of fop herbicide at 100 g a.i. ha-1 kept the weed density and dry weight reasonably at a lower level and enhanced the productivity of onion with higher economic returns. A rapid, sensitive, and analytical method was developed using high-performance liquid chromatography (HPLC) with excellent linearity (r2 > 0.99). The limit of quantification for quizalofop-p-ethyl was established at 0.04 mg kg-1 with signal to noise (S/N) ratio ≥ 10. The method was successfully applied and initial quantified residues were in the range of 2.5-4.4 mg kg-1 irrespective of seasons and doses. Finally, the presence of targeted herbicide residues in harvested samples was confirmed by liquid chromatography tandem mass spectrometry (LC-MS/MS) under optimized operating conditions. Dietary risk assessment assured harvested onions were safe for consumption at the recommended dose. It also can be concluded that quizalofop ethyl did not adversely influence soil micro-organisms at standard rates of application.

Review of extraction and detection techniques for the analysis of pesticide residues in fruits to evaluate food safety and make legislative decisions: Challenges and anticipations.

Fruits are vital parts of the human diet because they include necessary nutrients that the body needs. Pesticide use has increased dramatically in recent years to combat fruit pests across the world. Pesticide usage during production, on the other hand, frequently results in undesirable residues in fruits after harvest. Consumers are concerned about pesticide residues since most of the fruits are directly consumed and even recommended for the patients as dietary supplements. As a result of this worry, pesticide residues in fruits are being randomly monitored to re-assess the food safety situation and make informed legislative decisions. To assess the degree of pesticide residues in fruits, a simple and quick analytical procedure is usually required. As a result, pesticide residue detection (using various analytical techniques: GC, LC and Biosensors) becomes critical, and regulatory directives are formed to regulate their amounts via the Maximum Residue Limit (MRL). Over the previous two decades, a variety of extraction techniques and analytical methodologies for xenobiotic's efficient extraction, identification, confirmation and quantification have been developed, ranging from traditional to advanced. The goal of this review is to give readers an overview of the evolution of numerous extraction and detection methods for pesticide residue analysis in fruits. The objective is to assist analysts in better understanding how the ever-changing regulatory landscape might drive the need for new analytical methodologies to be developed in order to comply with current standards and safeguard consumers.

Simultaneous Monitoring and Decontamination of Pesticide Residues in Phytomedicine-Enriched Betel Leaf Utilizing QuEChERS-GC-MS/MS Technology to Safeguard Public Health.

BACKGROUND: The presence of undesirable substances, including pesticides (xenobiotics) in betel leaf (Piper betel), is a great concern for consumers because it is chewed and consumed directly. To protect the consumer's health, a modified QuEChERS method for monitoring purposes and subsequent decontamination process has been developed. OBJECTIVE: The goal of this work was to establish a multi-residue analytical method for monitoring nonpermitted organophosphorus pesticide residues in betel leaf, as well as cost-effective cleaning strategies. METHOD: The homogenized 15 g samples (20 betel leaf samples collected in West Bengal, India) were extracted with a modified QuEChERS method using acetonitrile, reconstituted to acetone, and finally analyzed by GC-MS/MS. Possible decontamination techniques (such as tap water washing, 2% saltwater washing, and lukewarm water washing) were evaluated. RESULTS: The limit of detection ranged from 0.003 to 0.005 mg/kg, and limit of quantification was 0.01 mg/kg. Recoveries ranged from 80 to 120% with RSDr 9%. One sample was found to contain three pesticides 4 to 7 times higher than MRLs. Suggested decontamination methods allowed reducing toxic traces below European limits. CONCLUSIONS: The suggested approach is useful for determining pesticide residues in betel leaves quickly. Traditional techniques of processing betel leaves may reduce pesticide residues below regulatory limits. HIGHLIGHTS: A multi-residue method and decontamination of pesticides in betel leaf using QuEChERS-GC-MS/MS technology with satisfactory method performance was achieved. Domestic decontamination techniques have a high efficacy in reducing pesticide residues from betel leaves, making them safe for human consumption.

Long-term profound investigation of Fenoxaprop-p-ethyl and indirect pesticide pollution in jute-cropped environmental ecosystem for dietary and ecological risk assessment.

Jute is a healthy vegetable due to its high content of carotenoids, vitamins, and minerals, in addition to its industrial utility. The purpose of this study was to look into the dissipation of fenoxaprop-p-ethyl and to track indirect sources of pesticide accumulation in jute ecosystems for three years in a row during tropical monsoon seasons. To avoid the intake of residues over approved limits, a rapid extraction technique was developed to evaluate the residues of this herbicide (Whip-Super 9% EC) in jute leaves, fiber, cropped soil, and water. A modified QuEChERS approach based on liquid chromatography and ultraviolet-visible (UV-VIS) detection was developed and successfully validated in accordance with SANCO requirements. Gas chromatography mass spectrometer (GC-MS) was used to examine fish and water samples from jute fields and retting pond for twenty widely-used multi-class pesticide contaminations from indirect sources. Relative standard deviations (RSD) (≤ 20) and recoveries (100-115%) are observed to be within acceptable ranges. In edible jute leaves, independent of season, first-order kinetics of dissipation was recorded, with half-lives ranging from 0.61 to 0.68 days. Based on the findings of the risk assessment, it is feasible to conclude that the consumer health risks of ingesting jute leaves are insignificant, even on day zero, when used at the recommended amount, and that using jute bags for food packaging and storage is safe. But jute field water was found to be less polluted with indirect pesticides than water from a nearby jute retted pond. Fish samples from this jute retted pond were also analyzed and found to be 26% contaminated. The presence of quinalphos and chlorpyriphos in jute retting water and fish might pose a concern to consumer health and environmental ecosystems.

Method development, validation, monitoring, seasonal effect and risk assessment of multiclass multi pesticide residues in surface and ground water of new alluvial zone in eastern India.

A liquid-liquid extraction (LLE) method was validated as per SANTE/12682/2019 guidelines for gas chromatography-mass spectrometric (GC-MS) determination of thirty-six multiclass pesticides in environmental waters. Seasonal (summer, monsoon, and winter) effects on the magnitude of pesticide residues in environmental water (river, pond, and tube well) of six different urban areas of Nadia and North 24 Parganas districts (New alluvial zone, Eastern India) was monitored for subsequent risk assessment. Total 288 water samples (96 each of river, pond, and tube-well) irrespective of locations and seasons were monitored for multiclass multi pesticide residues during the experiment. Each sample (750 mL) was extracted with ethyl acetate/dichloromethane (8:2) liquid-liquid partitioning and filtration (0.22 µm nylon filter paper) and total residue was reconstituted in acetone (1 mL) for GC-MS analysis with developed and validated method resulting satisfactory recovery percentages (77.84-118.15%). The maximum no. of organochlorine (OC) and organophosphorus (OP) pesticide residues were dominated in river and pond water irrespective of seasons and monitoring sites. About 74% of river water samples were found to be contaminated with concerned pesticides in variable magnitudes. Monsoon (July to October) season was highly alarming with the highest presence of total pesticide residues in different types of environmental waters. Risk quotient (RQ) [acute and chronic] was also evaluated in pond and river water as sometimes used for drinking purposes. RQ value (5900) of total endosulfan indicates the highest risk of chronic toxicity to river fishes. Seven water samples from tube-wells were also monitored and found to be contaminated with butachlor and chlorpyriphos in non-significant amounts (< 0.1 ng mL-1), irrespective of seasons and sites, thus safe for consumption.

Bioefficacy, residue dynamics and dietary risk assessment of gibberellic acid in improving the potential yield of tomato (Solanum lycopersicum L.).

The increasing use of gibberellic acid (GA3) to promote fruit growth and yield has necessitated research into its trace level determination and estimation in harvested product. The phytohormone has increased the tomato yield (tonne ha-1) up to 24.7% with uniform fruit shape, size colour and lustre. A fast, simple, high-throughput analytical method was standardised based on electrospray ionisation - liquid chromatography-tandem mass spectrometry (LC-MS/MS). The samples were extracted using acidified (1% formic acid) methanol. The method was validated as per the SANTE/12682/2019 guidelines. The limits of detection (LOD) and quantification (LOQ) were 0.01 and 0.05 mg kg-1. The average recoveries at LOQ and higher levels were in the range of 86-108% with relative standard deviation (RSD) < 20%. The validated method was successfully applied under field condition by following first-order kinetics with half-lives (T1/2) 1.76 days (recommended dose) and 1.99 days (double dose). The estimated pre-harvest intervals (PHIs) were 6 days (recommended dose) and 8 days (double dose). Studies on dietary risk assessment concluded that even after spray of GA3 at recommended dose, the harvested produce (tomato) could be consumed safely.

Method validation, persistence, and safety evaluation of 2,4-D in tea (Camellia sinensis) by LC-MS/MS.

An analytical method was developed by using LC-ESI(-ve)-MS/MS to investigate the residue dynamics of 2,4-D (2,4-dichlorophenoxyacetic acid) in green tea leaves, processed tea, tea liquor, and tea-cropped soil at Singhiajhora Tea Estate and Putinbari Tea Estate at Terai Region, Darjeeling District, West Bengal, India. In this method, an acidified methanol was used for extraction and subsequent clean-up was done by HLB (hydrophilic lipophilic balanced) cartridges. The method was validated as per SANTE guideline (SANTE/11813/2017). The limit of quantification (LOQ) of 2,4-D was 0.05 mgkg-1 and average % recoveries were in the range from 88.05 to 113.28 with relative standard deviation (RSD) 3.46 to 6.43. The dissipation of 2,4-D followed the 1st-order reaction kinetics with a half-life (T1/2) of 1.51-1.61 day at the recommended dose and 2.50-2.72 day for doubled recommended dose in tea for both locations. This method can be applied successfully for the determination of 2,4 D residues in/on tea matrix and subsequent studies on safety evaluation showed that the use of 2,4-D in tea is safe.

Multiclass Multipesticide Residue Analysis in Fish Matrix by a Modified QuEChERS Method Using Gas Chromatography with Mass Spectrometric Determination.

BACKGROUND: Pesticide residue in fish is a global food safety concern. However, very few validated methods are available targeting simultaneous analysis of multiple classes of pesticides. OBJECTIVE: The aim of this study was to validate a quick, easy, cheap, effective, rugged, and safe workflow-based method for the quantitative determination of multiclass pesticides in fish matrix using GC-MS determination. METHOD: The sample was extracted with acetonitrile, and the cleanup method involved dispersive solid-phase extraction with C-18 sorbent, which effectively scavenged the coextracted matrix components and removed those from the extract. The data on recovery and precision of the method satisfied the criteria of SANTE/11813/2017 guidelines. Average recoveries of pesticides were in the range of 80-120% with precision RSDs ≤20%. The LOD and LOQ were in the ranges of 0.001-0.029 and 0.005-0.125 µg/mL, respectively, for all pesticides. The expanded uncertainty was in the range of 14-20%, based on the single-laboratory validation data (coverage factor, k = 2, confidence level, 95%). CONCLUSIONS: The validation data prove that the method is convenient and acceptable for the routine analysis of multiclass pesticide residues in fish matrices for regulatory compliance. HIGHLIGHTS: The study achieves multiresidue analysis of pesticides in fish matrix with MS-based confirmation. The method combines the advantages of nontarget analysis based on National Institute of Standards and Technology library matching in full scan mode with selected-ion monitoring-based sensitivity.

Structure-toxicity relationship of chloroacetanilide herbicides: relative impact on soil microorganisms.

The research was carried out to ascertain the effect of three chloroacetanilide herbicides, alachlor, butachlor and pretilachlor on soil microbial biomass growth and activity. Laboratory experiments were performed in a silty clay loam soil to relate changes of soil enzymatic activity to the herbicide persistence under laboratory condition up to 42 days at three application rates. The results showed that all the three herbicides caused enhancement of dehydrogenase activity. Higher concentrations of herbicide resulted in enhancement of the enzymatic activity. In addition, a similar trend was observed in ß-glucosidase and acid phosphatase activity, although urease activity decreased upon incubation for 42 days as compared with initial soil incubation values. Based on the extent of impact for dehydrogenase activity in soil, the order was pretilachlor>alachlor>butachlor; whereas in case of urease activity, the order changed to pretilachlor>butachlor>alachlor. The soil half-lives of alachlor, butachlor and pretilachlor respectively, were 9.3, 12.7 and 7.3 days, which could be accounted for in terms of their respective chemical structures, as well as variable adsorption, degradation, differential effects of the agents on soil microbes. Soil management practices and the differing physicochemical properties of the herbicides may contribute to their rates of decay in soil.

Water based microwave assisted extraction of thiamethoxam residues from vegetables and soil for determination by HPLC.

A microwave assisted extraction (MAE) method for determination of thiamethoxam residues in vegetable and soil samples was standardized. Insecticide spiked vegetable and soil samples were extracted by MAE using water as an extraction solvent, cleaned up by solid phase extraction and analysed by high performance liquid chromatography on photodiode array detector. The recoveries of the insecticide from various vegetable (tomato, radish, brinjal, okra, French been, sugarbeet) and soil (sandy loam, silty clay loam, sandy clay loam, loamy sand) samples at 0.1 and 0.5 µg g(-1) spiking levels ranged from 79.8% to 86.2% and from 82.1% to 87.0%, respectively. The recoveries by MAE were comparable to those obtained by the conventional blender and shake-flask extraction techniques. The precision of the MAE method was demonstrated by relative standard deviations of <3% for the insecticide.

Comparative metabolite profiling of the insecticide thiamethoxam in plant and cell suspension culture of tomato.

The metabolism of thiamethoxam [(EZ)-3-(2-chloro-1,3-thiazol-5-yl-methyl)-5-methyl-1,3,5-oxadiazinan-4-ylidene (nitro) amine] was investigated in whole plant, callus, and heterotrophic cell suspension culture of aseptically and field grown tomato (Lycopersicon esculentum Mill.) plants. The structure of the metabolites was elucidated by chromatographic (HPLC) and spectroscopic (IR, NMR, and MS) methods. Thiamethoxam metabolism proceeded by the formation of a urea derivative, a nitroso product, and nitro guanidine. Both urea and nitro guanidine metabolites further degraded in plants, and a mechanism has been proposed. In the plant, organ-specific differences in thiamethoxam metabolism were observed. Only one metabolite was formed in whole plant against four in callus and eight metabolites in cell suspension culture under aseptic conditions. Out of six metabolites of thiamethoxam in tomato fruits in field conditions, five were similar to those formed in the cell suspension culture. In the cell suspension culture, thiamethoxam degraded to maximum metabolites within 72 h, whereas in plants, such extensive conversion could only be observed after 10 days.

Persistence, metabolism and safety evaluation of thiamethoxam in tomato crop.

BACKGROUND: Thiamethoxam, a neonicotinoid insecticide, has been widely accepted for use in various crops, including vegetables, owing to its high efficacy against various chewing and sucking insect pests. In this particular study, the authors examined the residue dynamics of this insecticide in tomato and soil and calculated a safety index for this insecticide in an Indian context. RESULTS: In tomato fruits, the insecticide dissipated from 82 to 87% in 10 days with a half-life of 4 days, whereas dissipation in soil, under tomato crop, varied between 72 and 75% in 15 days with a half-life of 9 days. Total residues reached below detectable level in 15 days in tomato fruits and 20 days in soil. Maximum damage (30%) was found in control plots, as opposed to 8-10% of fruit damage in treated plots. One degradation product was detected on the tomato fruit surface, and three metabolites were identified in tomato fruits by the LC-MS technique. The metabolites have been reported for the first time in tomato fruits. CONCLUSION: Thiamethoxam at normal and double the recommended use rate effectively controlled aphids, whiteflies and Helicoverpa, as the insect population decreased to a minimum within 10 days of spraying in comparison with the control. There was no significant difference between the two rates of application, and both thiamethoxam treatments significantly increased tomato fruit yield compared with the untreated control. A maximum residue limit (MRL) of 0.05 mg kg(-1) for tomato has been proposed, with a corresponding preharvest interval (PHI) of 8 days. These parallel advances in toxicology and analytical chemistry have strengthened the observations that thiamethoxam can be used safely and efficiently in crop protection programmes.

Kinetics and mechanism of the hydrolysis of thiamethoxam.

The degradation of thiamethoxam [(EZ)-3-(2-chloro-1,3-thiazol-5-yl-methyl)-5-methyl-1,3,5-oxadiazinan-4-ylidene (nitro) amine] insecticide in buffers at different pH and temperature levels was investigated in laboratory studies. Acidic hydrolysis under conventional heating conditions and alkaline hydrolysis under both conventional heating and microwave conditions were carried out. Different hydrolysis products were found to form under alkaline and acidic conditions. Hydrolysis of thiamethoxam in acidic, neutral and alkaline buffers followed first-order reaction rate kinetics at pH 4, 7 and 9.2, respectively. Thiamethoxam readily hydrolyzed in alkaline buffer but was comparatively stable in neutral buffer solution. The main products formed under different conditions were characterized on the basis of infrared (IR), (1)H-NMR and Mass spectroscopy. The possible mechanisms for the formation of these hydrolysis products have also been proposed.