Recent Modifications and Validation of QuEChERS-dSPE Coupled to LC-MS and GC-MS Instruments for Determination of Pesticide/Agrochemical Residues in Fruits and Vegetables: Review

Comprehensive analysis of contaminants in Brazilian infant formulas: Application of QuEChERS coupled with UHPLC-QqQ-MS/MS and suspect screening-unknown analysis by UHPLC-Q-Orbitrap-MS

Infant formulas (IF) can contain harmful chemical substances, such as pesticides and mycotoxins, resulting from the contamination of raw materials and inputs used in the production chain, which can cause adverse effects to infants. Therefore, the quick, easy, cheap, effective, rugged, and safe (QuEChERS) methodology prior ultra-high performance liquid chromatography coupled to triple quadrupole mass spectrometry (UHPL-QqQ-MS/MS) analysis was applied for the determination of 23 contaminants, in 30 samples of Brazilian IF. The method was validated in terms of limit of detection (0.2 to 0.4 μg/kg), limits of quantification (1 and 10 μg/kg), and recovery (64 % to 122 %); precision values, in terms of relative standard deviation (RSD), were ≤ 20 %. Fenitrothion, chlorpyrifos, and bifenthrin were the pesticides detected in the samples, but the values did not exceed the limit set by the European Union (EU), and ANVISA, and they were detected under their limits of quantification. Additionally, suspect screening and unknown analysis were conducted to tentatively identify 32 substances, including some compounds not covered in this study, such as pesticides, hormones, and veterinary drugs. Carbofuran was identified, confirmed and quantified in 10 % of the samples.

Validation and application of a method for determination of multi-class pesticides in muscle chicken breast fillets using QuEChERS extraction and GC/MS

Introduction

The occurrence of pesticide residues in animal products deserves attention because of the contamination by environmental pollutants and pesticides that may be present in the food that animals are fed. The goal of this work was the validation of a method for detection of residues of multiple classes of pesticide and determination of their residues in chicken breast fillets.

Material and Methods

Gas chromatography with mass spectrometry was used for analysis. A modified quick, easy, cheap, effective, rugged and safe (QuEChERS) method was put into practice for its validation and applied to real samples. The study optimised mass detection and investigated the effect of a freezing step during the preparation of samples. Pesticides were determined in samples from conventional and organic production.

Results

The impact of the matrix effect decreased, with the largest number of pesticides and satisfactory recovery determined by the application of mixed solvent acetonitrile and ethyl acetate for extraction. Detection of pesticide residues was achieved in a linear range between 5 and 50 µg/kg with satisfactory excellent correlation coefficients greater than 0.99. The recovery of all the pesticide residues ranged between 71.2 and 118.80%. The relative standard deviation was from 2.9% to 18.1% for all validated pesticide residues. The limits of quantification were in the range of 3.0-4.9 µg/kg. Out of 56 pesticide residues analysed in real samples, 5 were detected: α endosulfan, cypermethrin, endosulfan sulphate, permethrin and p,p´-dichlorodiphenyltrichloroethane (DDT) and their concentrations ranged from 4.9 to 15.2 µg/kg.

Conclusion

All tested samples were compliant with the evaluation criteria, and detected values of pesticide residues were lower than the maximum residual levels.

Optimization and validation of multiresidual extraction methods for pharmaceuticals in Soil, Lettuce, and Earthworms

The presence of human and veterinary pharmaceuticals (PhACs) in the environment poses potential risks. To comprehensively assess these risks, robust multiresidual analytical methods are essential for determining a broad spectrum of PhAC classes in various environmental compartments (soil, plants, and soil organisms). This study optimized extraction methods for analyzing over 40 PhACs from various matrices, including soil, lettuce, and earthworms. A four-step ultrasonic extraction method with varying extraction conditions and subsequent solid phase extraction was developed for soil samples. QuEChERS methods were optimized for extracting PhACs from lettuce and earthworm samples, addressing a literature gap in these less-studied matrices. The quantification of PhACs in soil, lettuce, and earthworm extracts was performed using a single LC-MS/MS method. Following thorough method validation, earthworms and lettuce were exposed to a mixture of 27 pharmaceuticals in a soil environment. The method validation results demonstrated the robustness of these methods for a broad spectrum of PhACs. Specifically, 29 out of 42 PhACs were extracted with an average efficiency > 50% and RSD < 30% from the soil; 40 out of 42 PhACs exhibited average efficiency > 50% and %RSD < 30% from the earthworms, while 39 out of 42 PhACs showed average efficiency > 50% and RSD < 30% from the lettuce. Exposure experiments confirmed the viability of these methods for quantifying a diverse range of PhACs in different environmental compartments. This study presents three thoroughly validated methods for determining more than 40 PhACs in diverse matrices, enabling a comprehensive assessment of PhAC dissemination in the environment.

Fluorescent aptasensor mediated with multiple ssDNA for sensitive detection of acetamiprid in vegetables based on magnetic Fe3O4/C-assisted separation

Acetamiprid (ACE) is a highly effective broad-spectrum insecticide, and its widespread use is potentially harmful to human health and environmental safety. In this study, magnetic Fe3O4/carbon (Fe3O4/C), a derivative of metal-organic framework MIL-101 (Fe), was synthesized by a two-step calcination method. And a fluorescent sensing strategy was developed for the efficient and sensitive detection of ACE using Fe3O4/C and multiple complementary single-stranded DNA (ssDNA). By using aptamer with multiple complementary ssDNA, the immunity of interference of the aptasensor was improved, and the aptasensor showed high selectivity and sensitivity. When ACE was present, the aptamer (Apt) combined with ACE. The complementary strand of Apt (Cs1) combined with two short complementary strands of Cs1, fluorophore 6-carboxyfluorescein-labeled complementary strand (Cs2-FAM) and the other strand Cs3. The three strands formed a double-stranded structure, and fluorescence would not be quenched by Fe3O4/C. In the absence of ACE, Cs2-FAM would be in a single-chain state and would be adsorbed by Fe3O4/C, and the fluorescence of FAM would be quenched by Fe3O4/C via photoelectron transfer. This aptasensor sensitively detected ACE over a linear concentration range of 10-1000 nM with a limit of detection of 3.41 nM. The recoveries of ACE spiked in cabbage and celery samples ranged from 89.49% to 110.76% with high accuracy.

Knowledge, attitude and practices of farmers and experts about the effects of pesticide residues on agricultural product users and ecosystems: A case of Fogera District, Ethiopia

Pesticides are chemicals used to control different types of pests. Though pesticides played a role in improving the quantity and quality of production, they have been threatening ecosystems and posed effects on humans in different parts of the world. Unfortunately, there were no studies made about the effects of pesticide residues on ecosystems and consumers in the Fogera District of Amhara Region, Ethiopia. Hence, the main objective of this study was to understand the knowledge, attitude, and practices of respondents about the effects of pesticide residues on ecosystems and consumers. A cross-sectional survey complemented by focus group discussions and field observations was used to gather the required data for the study. The close-ended data were analyzed using descriptive statistics, logistic regressions, and independent t-test, and data from open-ended questions were grouped and summarized based on their similarities. The findings of the study confirmed that there was significant knowledge, attitude, and practices difference between farmers and consumers about the effects of pesticide residues on ecosystems and humans. Farmers used highly toxic pesticides to control pests and improve the glossiness of vegetables and khat. Though they didn't use the sprayed vegetables for their home consumption, some of the farmers deliberately supplied pesticide-sprayed vegetables without worrying about the negative effects of the pesticides on the consumers. There were also fishing practices from rivers after intoxicating the fish using the pesticide sprayed feed. This, in turn, might poison individuals who consume the fish. In general, pesticide application practices and consumption of pesticide-sprayed foodstuffs and surface water might pose serious health risks to ecosystems and humans. To minimize the negative effects of pesticides, rigorous awareness-raising on the effects and management of pesticides, enforcement of laws, delineation of the pesticide free buffer zone for waters, the establishment of a clear pesticide supply chain to the end users, ecosystem assessment and food safety monitoring schemes are highly required.

Application of Sorbent-Based Extraction Techniques in Food Analysis

This review presents an outline of the application of the most popular sorbent-based methods in food analysis. Solid-phase extraction (SPE) is discussed based on the analyses of lipids, mycotoxins, pesticide residues, processing contaminants and flavor compounds, whereas solid-phase microextraction (SPME) is discussed having volatile and flavor compounds but also processing contaminants in mind. Apart from these two most popular methods, other techniques, such as stir bar sorptive extraction (SBSE), molecularly imprinted polymers (MIPs), high-capacity sorbent extraction (HCSE), and needle-trap devices (NTD), are outlined. Additionally, novel forms of sorbent-based extraction methods such as thin-film solid-phase microextraction (TF-SPME) are presented. The utility and challenges related to these techniques are discussed in this review. Finally, the directions and need for future studies are addressed.

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.

Factors Affecting Incurred Pesticide Extraction in Cereals

This study investigated the effect of milling on the yields of incurred residues extracted from cereals. Rice, wheat, barley, and oat were soaked in nine pesticides (acetamiprid, azoxystrobin, imidacloprid, ferimzone, etofenprox, tebufenozide, clothianidin, hexaconazole, and indoxacarb), dried, milled, and passed through sieves of various sizes. The quick, easy, cheap, effective, rugged, and safe method and liquid chromatography-tandem mass spectrometry extracted and quantified the incurred pesticides, respectively. For rice and oat, the yields were higher for vortexed samples than for soaked samples. For rice, the yields improved as the extraction time increased from 1 to 5 min. The optimized method was validated based on the selectivity, limit of quantitation, linearity, accuracy, precision, and the matrix effect. For rice and barley, the average yields improved as the particle size decreased from <10 mesh to >60 mesh. For 40-60-mesh wheat and oat, all pesticides (except tebufenozide in oat) had the highest yields. For cereals, 0.5 min vortexing, 5 min extraction, and >40-mesh particle size should be used to optimize incurred pesticide extraction.

Rapid Identification and Analysis of Ochratoxin-A in Food and Agricultural Soil Samples Using a Novel Semi-Automated In-Syringe Based Fast Mycotoxin Extraction (FaMEx) Technique Coupled with UHPLC-MS/MS

In this work, a fast mycotoxin extraction (FaMEx) technique was developed for the rapid identification and quantification of carcinogenic ochratoxin-A (OTA) in food (coffee and tea) and agricultural soil samples using ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) detection. The FaMEx technique advancement is based on two plastic syringes integrated setup for rapid extraction and its subsequent controlled clean-up process. In the extraction process, a 0.25-g sample and extraction solvent were added to the first syringe barrel for the vortex-based extraction. Then, the extraction syringe was connected to a clean-up syringe (pre-packed with C18, activated carbon, and MgSO₄) with a syringe filter. Afterward, the whole set-up was placed in an automated programmable mechanical set-up for controlled elution. To enhance FaMEx technology performance, the various influencing sample pretreatment parameters were optimized. Furthermore, the developed FaMEx method indicated excellent linearity (0.9998 and 0.9996 for coffee/tea and soil) with highly sensitive detection (0.30 and 0.29 ng/mL for coffee/tea and soil) and quantification limits (1.0 and 0.96 for coffee/tea and soil), which is lower than the toxicity limit compliant with the European Union regulation for OTA (5 ng/g). The method showed acceptable relative recovery (84.48 to 100.59%) with <7.34% of relative standard deviation for evaluated real samples, and the matrix effects were calculated as <-13.77% for coffee/tea and -9.7 for soil samples. The obtained results revealed that the developed semi-automated FaMEx/UHPLC-MS/MS technique is easy, fast, low-cost, sensitive, and precise for mycotoxin detection in food and environmental samples.

Simultaneous Quantification of Opioids in Blood and Urine by Gas Chromatography-Mass Spectrometer with Modified Dispersive Solid-Phase Extraction Technique

Common methodologies such as liquid-liquid extraction and solid-phase extraction are applied for the extraction of opioids from biological specimens i.e., blood and urine. Techniques including LC-MS/LC-MSMS, GC-MS, etc. are used for qualitative or quantitative determination of opioids. The goal of the present work is to design a green, economic, rugged, and simple extraction technique for famous opioids in human blood and urine and their simultaneous quantification by GC-MS equipped with an inert plus electron impact (EI) ionization source at SIM mode to produce reproducible and efficient results. Morphine, codeine, 6-acetylmorphine, nalbuphine, tramadol and dextromethorphan were selected as target opioids. Anhydrous Epsom salt was applied for dSPE of opioids from blood and urine into acetonitrile extraction solvent with the addition of sodium phosphate buffer (pH 6) and n-hexane was added to remove non-polar interfering species from samples. BSTFA was used as a derivatizing agent for GC-MS. Following method validation, the LOD/LLOQ and ULOQ were determined for morphine, codeine, nal-buphine, tramadol, and dextromethorphan at 10 ng/mL and 1500 ng/mL, respectively, while the LOD/LLOQ and ULOQ were determined for 6-acetylmorphine at 5 ng/mL and 150 ng/mL, respectively. This method was applied to real blood and urine samples of opioid abusers and the results were found to be reproducible with true quantification.

Effect of Talc Particle Size in Detergents for Fruits and Vegetables on the Ability to Remove Pesticide Residues

Detergents containing abrasive talc particles for washing fruits and vegetables were designed and investigated. Detergent prototypes were developed with the following composition: 40% talc particles, 1.5% surfactants, 5% ethyl alcohol, 1% sodium citrate, 1% sodium carbonate, 1.5% glycerin, and 0.5% preservative. Xanthan gum (0.5% concentration) was used as a viscosity modifier to stabilize the dispersion of talc particles. Three types of detergent prototypes were prepared, differing in the size of the talc particles. The following fractions were used: 50-125, 250-500, and 710-1000 μm. The particle size effect on the effectiveness of the removal of surface pesticide residues was investigated. A specially developed methodology was used. Three types of pesticides (boscalid, acetamiprid, and pyraclostrobin) were applied to a cherry tomato, tangerine, and cucumber, and then a model washing process was performed using the developed detergents. The changes in the pesticide content on the surface of fruit and vegetables were assessed by liquid chromatography-tandem mass spectrometry. Detergents with talc particles of sizes 50-125 and 250-500 μm were more efficient in the removal of pesticide residues from the surface of fruit and vegetables compared to detergents with 710-1000 μm talc particles.

Multi-residue Analysis, Probabilistic Dietary Risk Assessment of 241 Pesticides in Wheatgrass (Triticum sp.) using LC-MS/MS in Combination with QuEChERS Extraction

Wheatgrass is consumed as an important nutritious herbal food supplement across the globe; however, limited studies have been reported on analysis of multi-class pesticides in this complex nutrient rich natural product. An analytical method was developed for the estimation of 241 pesticides in random Wheatgrass samples collected from Delhi-Northern Capital Region (Delhi-NCR). Extraction was performed by QuEChERS, cleaning was performed by dispersive solid phase and the extracts were analyzed using Triple Quadrupole Liquid Chromatography Mass Spectrometry. The limit of quantification was 0.5 μg /kg, which is well below European Union-Maximum Residue Level. The coefficient of determination was >0.991 across calibration range of 0.5-100 μg /kg. The Relative Standard Deviation values for 231 pesticides based on 10 replicates of samples spiked at 10 μg /kg were <5%. Among random samples, 54% confirmed the presence of at least one pesticide. Results indicated the presence of 8 different pesticides among 38% of total population with Metribuzin at 299.7 μg /kg and Carfentrazone-ethyl at 19.47 μg/kg exceeding the permissible limits among 6% of total estimated population. The chronic and acute risk quotients as calculated were less than 1, indicating non-significant dietary risk to consumers. However, the presence of pesticides above permissible limit is likely to result in adverse health effects to the consumers of herbal supplements from urban population and incorporating measures would be useful to ensure the quality and safety of wheatgrass consumption.

Dissipation pattern and dietary risk assessment of some commonly used insecticides on tomato (Solanum lycopersicum L.)

Pesticide residue in food commodities is a serious concern in relation to the consumer safety and also the most significant barrier in the trade of food commodities. The dissipation pattern of four insecticides viz., novaluron, λ-cyhalothrin, imidacloprid, and fenazaquin was evaluated on tomato fruits and cropped soil. The residues were extracted using the QuEChERS analytical method and quantized using GC-ECD, GC-MS, and HPLC-PDA. The analytical method was validated using parameters like recovery, linearity, accuracy, matrix effect, specificity with limit of detection and limit of quantitation established to be 0.01 and 0.05 mg kg-1, respectively for all the pesticides. The average initial deposits (samples collected after two hours of spray) at recommended dose of novaluron, λ-cyhalothrin, imidacloprid and fenazaquin were 0.593, 0.293, 0.227 and 0.431 mg kg-1 on tomato fruits, respectively and were below the limit of quantification in soil. The pre-harvest interval of 17, 8, 1 and 13 days were suggested for novaluron, λ-cyhalothrin, imidacloprid and fenazaquin on tomato, respectively. The risk assessment studies revealed that all pesticides under study are safe and did not pose any threat to humans as (TMDI) theoretical maximum dietary intake is less than maximum permissible intake (MPI) and acceptable daily intake (ADI).

Zeolitic imidazolate framework-8 as a dispersive solid phase extraction sorbent for simultaneous determination of 145 pesticide residues in polyphenol-rich plants

Many plants showed higher polyphenol content, which caused the matrix effect and made the analysis of trace pesticide residues highly challenging. A common approach to improving matrix effects is to purify pesticides through the use of sorbents, but this requires a combination of multiple sorbents and extensive use. Zeolitic imidazolate framework-8 is widely used for pesticide analysis due to its high porosity, large specific surface area and versatility. Here, We established and validated a modified quick, easy, cheap, effective, rugged, and safe method based on a zeolitic imidazolate framework-8 that was used to test the removal ability for polyphenols. And 145 pesticide residues in peppermint, perilla, fennel, and mulberry leaves were analyzed by the modified method coupled with LC-MS/MS. The mean recoveries of all pesticide residues were in the range of 74.3%-103.7%, with mean relative standard deviations≤ 9.1% at spiked concentrations of 1, 10, 50, and 100 μg kg^-1 for mulberry leaves. The limits of quantitation of the method ranged from 1 to 50 μg kg^-1 . This study offers a reliable approach for the accurate quantitative analysis of various trace substances in the polyphenol-rich plants. This article is protected by copyright. All rights reserved.

Chromatographic techniques for the analysis of organophosphate pesticides with their extraction approach: a review (2015-2020)

In agriculture, a wide range of OPPs has been employed to boost crop yield, quality, and storage life. However, due to the ever-increasing population and rapid urbanization, pesticide use has surged in recent years. These compounds are exceedingly poisonous to humans, and despite the fact that specific legislation prohibits their use, the frequency of toxic and/or fatal incidents, as well as current statistics, suggest that they are currently accessible. As a result, determining the exposure to these substances as well as their detection (and that of their metabolites) in different types of exposed samples has become a hot issue in terms of quality and safety concerns. However, developing tools for the evaluation of these substances is a critical challenge for laboratories. Various chromatographic-based methods reported in the period of 2015-2020 have been developed, which are summarized and critically reviewed in this article, including the extraction of the target OPPs from different kinds of matrices. A comparison among the extraction and analysis techniques has been made in the current review article.

Evaluation of rapid and standard tandem mass spectrometric methods to analyse veterinary drugs and their metabolites in antemortem bodily fluids from food animals

Antemortem bodily fluids can serve as an indicator of veterinary medicine exposure prior to food animal slaughter. A multi-residue, rapid screen electrospray ionisation mass spectrometric (RS-ESI-MS) method was developed to analyse 10 veterinary drugs or metabolites (clenbuterol, erythromycin, flunixin, 5-hydroxyflunixin, meloxicam, ractopamine, ractopamine-glucuronide, salbutamol, tylosin, and zilpaterol) in hog oral fluid and bovine urine. Simple acetonitrile extraction with salting-out was employed to remove the analytes from matrices in less than 30 minutes. Instrumental analysis time was < 1 min/injection. Regression coefficients of matrix-matched calibration curves ranged 0.9743-0.9999 across all compounds with limits of detection ranging from 0.46-108 ng mL^-1 for cattle urine and 0.19-64.4 ng mL^-1 for hog oral fluid across all analytes. Except for ractopamine-glucuronide, analyte recoveries ranged from 92.7-106% for oral fluid and urine fortified at 30, 100, and 300 ng mL^-1, with inter-day variations of < 25%. Ractopamine-glucuronide recovery was 93.3% for oral fluid fortified at 300 ng mL^-1. The RS-ESI-MS method accurately identified ractopamine and/or ractopamine-glucuronide in incurred cattle urine with results correlating well with traditional LC-MS/MS and HPLC fluorescence methods. As far as we are aware, this is the first report of the direct quantification of ractopamine-glucuronide from biological matrices without lengthy hydrolysis and cleanup steps.

Optimization and Validation of a Multi-Residue Method for Screening of 126 Pesticide Residues in Herbal Raw Materials and Extracts Used as Ingredients in Ayurvedic Medicines and Dietary Supplements

BACKGROUND

Testing for pesticides levels in herbal products is an important aspect in determining product safety. Plants and its extracts are widely used as ingredients in botanical dietary supplements and traditional medicines. The extracts of plants, especially those prepared out of organic solvents are rich in secondary metabolites and pigments and adequate clean-up is required since the extracts completely dissolve in organic solvents.

OBJECTIVE

The study aims at reporting a multi-residue analytical method for 126 different pesticides in raw material biomass as well as extracts of plants, which are widely used as ingredients in ayurvedic medicines as well as dietary supplements using LC-MSMS and GC-MSMS with a rugged sample preparation technique for accurate results.

METHOD

QuEChERS, GPC, GPC coupled with SPE and LLE coupled with SPE sample preparation methods were compared against each other for suitability to test pesticides in selected herbal raw materials and its alcoholic and aqueous extracts. The standard addition method was used for quantifying the level of pesticides below 10 μg/Kg.

RESULTS

Single laboratory validation for sample preparation involving GPC and SPE resulted linearity in the range of 2.5-500 ng/mL, average intra-day and inter-day precision of 6.6% RSD, and average recovery (spiked at 10 μg/Kg) of 92% for all analytes tested. The method was repeatable with different analysts and days.

CONCLUSIONS

The sample preparation technique combining GPC and SPE as well as LLE and SPE were the most suitable for the selected herbal alcoholic extracts whereas any of the regular techniques involving LLE, SPE, and QuEChERS were suitable for raw material biomass as well as aqueous extracts.

HIGHLIGHTS

The method was found to be capable of determining selected pesticides in the selected matrices at 10 μg/Kg concentration. Provision of recycling solvents used in GPC+SPE method was adopted to make the method environmentally friendly.

Applicability of Superheated Water Extraction for the Quantification of Pesticide Residues in Leafy Vegetables

Superheated water extraction (SWE) of pesticide residues in a cabbage sample was demonstrated. The recovery yields of several relatively polar pesticides (log P_ow < 3) by the spike-and-recovery method at 100°C were acceptable. Increasing the extraction temperature up to 150°C led to enhanced extraction efficiency except for pesticides that induced degradation. The recovery yields of some target pesticides having log P_ow values of 3.5 - 4 were effectively enhanced by increasing the number of extraction cycles. The observed concentration of fenitrothion in a cabbage sample was comparable with those by the official Japanese analytical method. These results suggested SWE is potentially suitable for the extraction of different relatively high-to-medium polarity pesticides.

Detection of Pesticide Residues in Vegetables Sold in Changchun City, China

ABSTRACT

We evaluated fresh vegetables for residues of 18 pesticides with different chemical structures, including organochlorine pesticides, organophosphorus pesticides, carbamate pesticides, and pyrethroid pesticides and estimated that the potential health risks for consumers. A total of 313 samples were collected from 12 kinds of vegetables in Changchun, the capital of Jilin Province, People's Republic of China. Pesticide residues were analyzed by gas chromatography and mass spectrometry, and the curves were highly linear at 0.01 to 1.00 μg/mL (R2 ≥ 0.99). The mean recovery rate of the pesticides was 62 to 110% (relative standard deviation of <5%). The limit of detection was 0.0001 to 0.0167 mg/kg, the limit of quantification was 0.0002 to 0.0556 mg/kg, and the overall detection rate was 28.43%. The prevalence of pesticides and of samples above the standard limit were highest in celery, the prevalence of pesticides was lowest in potatoes, and the prevalence of samples above the standard limit was lowest in cucumber. Three of the 18 pesticides were not detected: omethoate, chlorpyrifos, and fenvalerate. Among the 15 pesticides detected, the maximum risk factor of six (carbofuran, omethoate, phorate, dicofol, dimethoate, and dichlorvos) is >1, indicating possible harm to human health. Residues of a single pesticide may not adversely affect a person's health, but multiple pesticide residues could present a health risk.

HIGHLIGHTS

Multiresidue method for determining multiclass acidic pesticides in agricultural foods by liquid chromatography-tandem mass spectrometry

A reliable multiresidue method was developed for determining multiclass acidic pesticides in cereal grains, legumes, vegetables, and fruits. The target pesticides comprise 75 compounds, including phenoxy acid, sulfonylurea, imidazoline, and triazolopyrimidine herbicides, with acidic dissociation constant (pK_a) values of 1.9-5.9. The method includes extraction with acidified acetonitrile, salting out, cleanup with octadecyl silica and primary secondary amine cartridges, and subsequent liquid chromatography-tandem mass spectrometry. The analytical performance of the developed method was validated for nine foods (i.e., brown rice, soybeans, peanuts, spinach, cabbage, eggplant, potatoes, apples, and oranges) at a concentration of 0.01 mg kg^-1. Because matrix effects were negligible for most pesticide and food combinations, solvent-based calibration curves were used for quantification purposes. Most of the target compounds exhibited satisfactory analytical performance with trueness values of 70-100% and relative standard deviations below 14%. The high selectivity of the developed method was evidenced by the absence of interfering peaks near those of the target analytes. With the exception of 1-naphthaleneacetic acid, for which linearity was observed at 2.5-100 ng mL^-1, linear calibration curves were constructed for the target compounds in the 1-100 ng mL^-1 range, with coefficients of determination exceeding 0.995. The limits of detection were 3 μg kg^-1 or below in the examined matrices. The results demonstrate that the developed method is suitable for monitoring acidic pesticides in a variety of foods.

Simultaneous determination of 114 pesticides in complex Chinese herbal medicine Fritillaria using ordered mesoporous carbon CMK-3 as a reversed-dispersive solid phase extraction sorbent

Fritillaria, a traditional Chinese herbal medicine, is classified into many medicinal species and contains numerous complex components. It is thus difficult to simultaneously detect multiple pesticide residues in different Fritillaria species. An easy, reliable, and widely applicable analytical method based on a modified Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method coupled with LC-MS/MS was developed to solve these problems encountered during pesticide residue analysis in complex Fritillaria matrices. Ordered mesoporous carbon CMK-3 and a primary secondary amine (PSA) were used as efficient purification sorbents by optimization of the QuEChERS process. Systematic method validation was performed for four species of Fritillaria. The matrix effect of pesticides varied among different Fritillaria species, and matrix-matched standard solutions were thus employed for quantitative analysis. The mean recoveries of all pesticides ranged from 88.6% to 95.5%, with mean relative standard deviations (RSD) lower than 6% at spiked concentrations of 30, 120, and 240 μg kg⁻¹. The limits of quantification (LOQ) for the developed method were in the range of 30–120 μg kg⁻¹. This method was further used to analyze 47 Fritillaria samples from Zhejiang province, China, and seven pesticides were detected in 22 Fritillaria samples. These results demonstrate that the developed method is suitable for an accurate analysis of multiple pesticide residues in various Fritillaria.

Fritillaria, a traditional Chinese herbal medicine, is classified into many medicinal species and contains numerous complex components.

Recent Materials Developed for Dispersive Solid Phase Extraction

Solid phase extraction (SPE) is an analytical procedure developed with the purpose of separating a target analyte from a complex sample matrix prior to quantitative or qualitative determination. The purpose of such treatment is twofold: elimination of matrix constituents that could interfere with the detection process or even damage analytical equipment as well as enriching the analyte in the sample so that it is readily available for detection. Dispersive solid phase extraction (dSPE) is a recent development of the standard SPE technique that is attracting growing attention due to its remarkable simplicity, short extraction time and low requirement for solvent expenditure, accompanied by high effectiveness and wide applicability. This review aims to thoroughly survey recently conducted analytical studies focusing on methods utilizing novel, interesting nanomaterials as dSPE sorbents, as well as known materials that have been only recently successfully applied in dSPE techniques, and evaluate their performance and suitability based on comparison with previously reported analytical procedures.

Development and Application of a Multi-Residue Method to Determine Pesticides in Agricultural Water Using QuEChERS Extraction and LC-MS/MS Analysis

Agricultural water is closely linked to surface and ground water as well as soil; hence, ensuring its safety is an important endeavor. We used the “quick, easy, cheap, effective, rugged, and safe” (QuEChERS) method to analyze multi-residue pesticides in agricultural water by using a combined-sorbent-based clean-up procedure. Among the various sorbents examined, clean-up using ENVI-Carb combined with a primary secondary amine sorbent delivered the highest recovery of multi-residue pesticides (>93.9%). While the developed method showed satisfactory linearity (R2 > 0.9991), precision, and specificity, recovery was low for pyrazolate (29.1%) and thidiazuron (59.2%). The limits of detection and quantification for the 55 pesticides targeted in this study were in 0.02–3.0 μg L−1 and 0.1–9.9 μg L−1, respectively. The developed method was used to identify and quantify multi-residue pesticides during sample analysis. The results suggest that the QuEChERS method employing a combination of ENVI-Carb and another sorbent can be applied for the effective analysis of multi-residue pesticides in agricultural water.

Miniaturized vortex assisted-dispersive molecularly imprinted polymer micro-solid phase extraction and HPLC-MS/MS for assessing trace aflatoxins in cultured fish

A dispersive micro-solid phase extraction approach using a molecularly imprinted polymer as an adsorbent has been developed for pre-concentrating aflatoxins from cultured fish. Aflatoxins were first isolated from fish muscle and liver by an ultrasound assisted extraction procedure using a 60 : 40 acetonitrile/0.1 M KH2PO4 aqueous buffer (pH 6.0) mixture. Polymeric adsorbent beads were synthesized using 5,7-dimethoxycoumarin as a dummy template, methacrylic acid as a functional monomer, divinylbenzene as a crosslinker, and 2,2'-azobisisobutyronitrile as an initiator. Parameters affecting the steps of extraction procedure, including the sample (fish extract) pH, adsorption stirring speed and time, desorption stirring speed and time, elution solvent ratio, and polymer capacity, were investigated and optimized. The limit of detection was found to vary from 0.29 to 0.61 μg kg-1 for the several aflatoxins. The proposed method was shown to be accurate and precise. Intraday and inter-day relative standard deviations were lower than 20%, and intraday and inter-day analytical recoveries were within the 80-100% range. The prepared adsorbent in the dispersive micro-solid phase extraction format was re-usable, and the pre-concentration procedure was found to be simple, rapid and highly selective and sensitive to identify/quantify AFs in fish.

Mass Spectrometry-Based Determination of Thyroid Hormones and Their Metabolites in Endocrine Diagnostics and Biomedical Research – Implications for Human Serum Diagnostics

The wide spectrum of novel applications for the LC-MS/MS-based analysis of thyroid hormone metabolites (THM) in blood samples and other biological specimen highlights the perspectives of this novel technology. However, thorough development of pre-analytical sample workup and careful validation of both pre-analytics and LC-MS/MS analytics, is needed, to allow for quantitative detection of the thyronome, which spans a broad concentration range in these biological samples.

This minireview summarizes recent developments in advancing LC-MS/MS-based analytics and measurement of total concentrations of THM in blood specimen of humans, methods in part further refined in the context of previous achievements analyzing samples derived from cell-culture or tissues. Challenges and solutions to tackle efficient pre-analytic sample extraction and elimination of matrix interferences are compared. Options for automatization of pre-analytic sample-preparation and comprehensive coverage of the wide thyronome concentration range are presented. Conventional immunoassay versus LC-MS/MS-based determination of total and free THM concentrations are briefly compared.

Integrated Approach to Evaluate the Association between Exposure to Pesticides and Idiopathic Premature Thelarche in Girls: The PEACH Project

Several pesticides are recognized as endocrine-disrupting chemicals (EDCs) since they can interfere with the dysregulation of sexual, thyroid and neuro-endocrine hormones. Children are particularly vulnerable to the adverse effects of EDCs due to their developmental stage, peculiar lifestyle and dietary habits. In this context, the exposure to pesticides represents an important risk factor associated with early development. This study deals with the possible association between exposure to pesticides and idiopathic premature thelarche in girls from areas of intensive agriculture practice in the Centre of Italy. An integrated approach was set up, including: (i) a case-control study on girls with idiopathic premature thelarche; (ii) the evaluation of multiple pesticides exposure in girls; (iii) the evaluation of multiple pesticides in food; (iv) the dietary intake of pesticide residues; (v) the assessment of toxicological effects of widely used pesticides by in vitro model. Data integration will provide an estimate of the predictive risk of potential effects on girls' health, linked to dietary intake.

Recent Trends in the Development of Green Microextraction Techniques for the Determination of Hazardous Organic Compounds in Wine

Background:

The sample preparation is the most crucial step in the analytical method development. Taking this into account, it is easily understood why the domain of sample preparation prior to detection is rapidly developing. Following the modern trends towards the automation, miniaturization, simplification and minimization of organic solvents and sample volumes, green microextraction techniques witness rapid growth in the field of food quality and safety. In a globalized market, it is essential to face the consumers need and develop analytical methods that guarantee the quality of food products and beverages. The strive for the accurate determination of organic hazards in a famous and appreciated alcoholic beverage like wine has necessitated the development of microextraction techniques.

Objective:

The objective of this review is to summarize all the recent microextraction methodologies, including solid phase extraction (SPE), solid phase microextraction (SPME), liquid-phase microextraction (LPME), dispersive liquid-liquid microextraction (DLLME), stir bar sorptive extraction (SBSE), matrix solid-phase dispersion (MSPD), single-drop microextraction (SDME) and dispersive solid phase extraction (DSPE) that were developed for the determination of hazardous organic compounds (pesticides, mycotoxins, colorants, biogenic amines, off-flavors) in wine. The analytical performance of the techniques is evaluated and their advantages and limitations are discussed.

Conclusion:

An extensive investigation of these techniques remains vital through the development of novel strategies and the implication of new materials that could upgrade the selectivity for the extraction of target analytes.

Synthesis of Au nanorod-embedded and graphene oxide-wrapped microporous ZIF-8 with high electrocatalytic activity for the sensing of pesticides

Multifunctional metal-organic framework-based composites display great potentials as electrode materials. Herein, highly dispersed Au nanorods were successfully encapsulated inside the zeolitic imidazolate framework ZIF-8 (AuNRs@ZIF-8) by epitaxial growth or nucleus coalescence. The microporous ZIF-8 shell functions as a protective coating to effectively prevent AuNRs from dissolution, aggregation, and migration during the electrochemical testing, while it provides numerous channels for the mass transfer of reactants to the AuNR surface. The as-synthesized AuNRs@ZIF-8 was then encapsulated in graphene oxide (GO) nanosheets to enhance the chemical resistance of the multicore-shell support, which possesses permanent porosity as well as high specific surface area and hydrophilicity. The excellent electrocatalytic performance of the resulting ternary AuNRs@ZIF-8@GO was demonstrated by the highly sensitive sensing of niclosamide, dichlorophen, carbendazim, and diuron, which outperformed the reported electrocatalysts for these four pesticides. This nanocomposite thus holds great promise as a catalyst for electrochemical sensor fabrication due to its abundant multiple active sites, enhanced catalytic activity, and remarkable stability.

Nontargeted Detection Methods for Food Safety and Integrity

Nontargeted workflows for chemical hazard analyses are highly desirable in the food safety and integrity fields to ensure human health. Two different analytical strategies, nontargeted metabolomics and chemical database filtering, can be used to screen unknown contaminants in food matrices. Sufficient mass and chromatographic resolutions are necessary for the detection of compounds and subsequent componentization and interpretation of candidate ions. Analytical chemistry–based technologies, including gas chromatography–mass spectrometry (GC-MS), liquid chromatography–mass spectrometry (LC-MS), nuclear magnetic resonance (NMR), and capillary electrophoresis–mass spectrometry (CE-MS), combined with chemometrics analysis are being used to generate molecular formulas of compounds of interest. The construction of a chemical database plays a crucial role in nontargeted detection. This review provides an overview of the current sample preparation, analytical chemistry–based techniques, and data analysis as well as the limitations and challenges of nontargeted detection methods for analyzing complex food matrices. Improvements in sample preparation and analytical platforms may enhance the relevance of food authenticity, quality, and safety.

Validating an ion mobility spectrometry-quadrupole time of flight mass spectrometry method for high-throughput pesticide screening

The utility of adding ion mobility (IM) to quadrupole time of flight mass spectrometry (IM-QTOF MS) for highly effective analysis of multiple pesticides in complex matrices was evaluated. Based on an in-house IM-MS database, the identification was performed through the match of the protonated ion ([M + H]+) and the CCS value. Moreover, the structural confirmation was achieved by using the accurate masses of [M + H]+ with its fragment ions, and the reference CCS value. The method did not require chromatographic separation and the analysis time of each measurement cycle is 1.6 min. The "cleaned" IM-MS spectra afforded by the drift time filtration improved the reliability of structural confirmation. As a result, the limit of detection (LOD) of 92% of test pesticides under the APCI mode and 58% of test pesticides under the ESI mode spiked in scallion was not more than 20 ng mL-1. In the analysis of practical samples, the identification of pyrimethanil was confirmed in celery, and benalaxyl and tebuconazole were identified as false positives in scallion. The time-saving, extended-scope and high-throughput method described in this work is capable of determining multiple pesticide residues in complex matrices with high sensitivity for monitoring applications.