QuEChERS Method Research Articles

Optimization of Ferimzone and Tricyclazole Analysis in Rice Straw Using QuEChERS Method and Its Application in UAV-Sprayed Residue Study

Rice straw is used as livestock feed and compost. Ferimzone and tricyclazole, common fungicides for rice blast control, can be found in high concentrations in rice straw after unmanned aerial vehicle (UAV) spraying, potentially affecting livestock and human health through pesticide residues. In this study, an optimized method for the analysis of the two fungicides in rice straw was developed using the improved QuEChERS method. After the optimization of water and solvent volume, extraction conditions including ethyl acetate (EtOAc), acetonitrile (MeCN), a mixed solvent, and MeCN containing 1% acetic acid were compared. Different salts, including unbuffered sodium chloride, citrate, and acetate buffer salts, were compared for partitioning. Among the preparation methods, the MeCN/EtOAc mixture with unbuffered salts showed the highest recovery rates (88.1–97.9%, RSD ≤ 5.1%). To address the severe matrix effect (%ME) of rice straw, which is characterized by low moisture content and cellulose-based complex matrices, samples were purified using 25 mg each of primary–secondary amine (PSA) and octadecylsilane (C18), without pesticide loss. The developed method was validated with a limit of quantification (LOQ) of 0.005 mg/kg for target pesticides, and recovery rates at levels of 0.01, 0.1, and 2 mg/kg met the permissible range (82.3–98.9%, RSD ≤ 8.3%). The %ME ranged from −17.6% to −0.3%, indicating a negligible effect. This optimized method was subsequently applied to residue studies following multi-rotor spraying. Fungicides from all fields and treatment groups during harvest season did not exceed the maximum residue limits (MRLs) for livestock feed. This confirms that UAV spraying can be safely managed without causing excessive residues.

Determination and Quantification of Folpet in Barley using HPLC-DAD Analysis

Although rоutinе pesticide analysеs are mostly performed using GC-MS, GC-MS/MS and/or LC-MS/MS, some pesticides especially those with relatively high MRLs and good detector response could also be precisely quantified with less sensitive equipment which gives the opportunity to some laboratories to expand their scope of work. The study focuses on HPLC-DAD method development for detection of folpet in barley grain. QuEChERS method was performed for extraction after which, additional clean-up was performed using PSA and polypropylene filtration. Pesticide separation was achieved using mobile phase of acidified CAN (pH 2.5) and water. The initial mobile phase was 60:40% (v/v), the elution gradient starts from 80:20% (v/v) to 100:0% (v/v) in 7 min and holds 100:0% (v/v) up to 8.5 min at a flow rate of 1 ml/min after which in the next 6.5 min the column was re-equilibrated to 40% phase-B. Calibration was performed using matrix-matched calibration standards. The obtained limits of detection (LOD) and quantification (LOQ) were 0.18 and 0.55 mg/kg, respectively, and the linear regression coefficient was 0.9973. Recovery, repeatability and reproducibility were investigated at three fortification levels (0.1 mg/kg, 0.6 mg/kg, and 1.6 mg/kg) and were found acceptable with relative standard deviation less than 10%. The method was applied for the analysis of three barley grain samples obtained from different producers and showed that folpet was present in one sample below the LOQ. Overall, the developed method is suitable for the determination of folpet in barley grains at levels below the established MRL of 1 mg/kg.

Multi-class, multi-residue analysis of pesticide residues in fishery products using LC and GC-MS/MS

Pesticide residues in agricultural products and the environment have been studied extensively over the years. Through the excessive or illegal use of pesticides, residues enter the surrounding environment and are absorbed by animals. Livestock and fishery products are subject to pesticide residue regulation, which includes the establishment of maximum residue limits. However, currently, fishery products are regulated only for ethoxyquin, neglecting the potential for bioaccumulation. This study aims to develop a method for the multi-class, multi-residue analysis of pesticide residues in fishery products—flatfish, eel, shrimp, and Manila clam—based on the QuEChERS method. A total of 327 compounds, including 263 pesticides and their metabolites, were identified using liquid chromatography and gas chromatography–tandem mass spectrometry. The method can quantify 263 pesticide residues in flatfish, 265 in eel, 264 in shrimp, and 263 in Manila clam, respectively. Additionally, the method can be applied to quantify 244 pesticide residues in seaweed. The method proves effective and useful for monitoring both food safety and environmental contamination.

Analysis, Quantification and Identification of Pesticides from Lettuce in Ouagadougou City (Burkina Faso)

In Burkina Faso, chemical inputs are used massively in market gardening to increase the yields. The misuse of these chemicals is responsible of contamination of market garden products, leading to the rapid rotting of vegetables. The objective of this study was to determine the pesticides in chemical inputs applied on vegetables produced in Ouagadougou City. To do this, lettuce has been sampled from producers in three sites (Tanghin, Boulmiougou and Kossodo) and pesticides amounts have been analyzed using Gas Chromatography coupled with mass spectrometry. Chemical analyses have carried out on three lettuce samples and the extraction of chemical input residues was done according to QuEChERS (Quick Easy Cheap Effective Rugged and Safe) method. Results revealed the presence of six (06) pesticide molecules (chlordimeform, quintozene, lindane, cypermethrin, α-cypermethrin, δ-deltamethrin) in Boulmiougou sample, four (04) molecules (methomyl, cypermethrin, α-cypermethrin, δ-deltamethrin) in Kossodo sample and three (03) molecules (cypermethrin, α-cypermethrin, δ-deltamethrin) in Tanghin sample. In this regard, analysis of pesticide amount revealed that the quantity of molecules was acceptable for the consumer, but these pesticides could contribute to the rapid rotting of our vegetables which generates economic and social losses for the country.

Development of a targeted LC-MS/MS method for the analysis of zero tolerance antimicrobials in buffalo meat

A simple, affordable, and efficient multiresidue analytical method was developed and validated using liquid chromatography-tandem mass spectrometry (LC-MS/MS) to accurately identify and quantify a prioritized zero-tolerance antimicrobial residues in buffalo meat. Analyzing zero-tolerance antimicrobials such as chloramphenicol, metronidazole, and nitrofurans involves detecting even trace levels of residues in food products to safeguard consumer safety and public health. A modified QuEChERS method with 2-nitrobenzaldehyde derivatization using ethyl acetate was employed for the extraction of the antimicrobial compounds, followed by a suitable clean-up. Liquid chromatographic conditions were optimized on a reverse phase C18 analytical column over a runtime of 12 min, and the eluted analytes were observed in selected reaction monitoring mode (SRM). The method's performance was validated in accordance with Regulation (EU) 2019/1871 and Commission Implementing Regulation (EU) 2021/810 guidelines. The linearity of the calibration curves was > 0.99, and the mean recoveries of the analytes ranged from 81.92 % to 110 %. The intra-day and inter-day precisions were less than 9 %. The limits of detection (LOD) and limits of quantification (LOQ) were in the range of 0.04–0.11 µg/kg and 0.13–0.37 µg/kg, respectively. This is well below the MRLs set by the European Commission for zero-tolerance substances.

Analytical control of residues of the herbicide trifluralin in the assessment of the food safety

Introduction. Trifluralin is a systemic herbicide of the chemical class of dinitroaniline derivatives. During monitoring studies, trifluralin was detected in carrots produced in the Russian Federation. Since trifluralin-based pesticides are not approved for the use in the Russian Federation, residual amounts of the substance are not typical for this crop. To check the contamination of carrots with a pesticide not typical for this crop, confirmatory qualitative and quantitative studies were carried out. Purpose of the work. Increasing the efficiency of identification and reliability of quantitative results when monitoring food products for safety when performing confirmatory analytical studies using the example of determining trifluralin in carrots to assess the safety of food products intended for the consumer. Materials and methods. Gas chromatography coupled with tandem mass spectrometry (GC-MS/MS) was used to identify and quantify trifluralin. Samples were prepared for analysis using the QuEChERS method. Identification was carried out by multiple reaction monitoring (MRM) using a triple quadrupole mass spectrometer using two to four MRM transitions (m/z): 306,1→264,0; 264,0→206,0; 264,0→188,0; 264,0→160,1. Matrix-matched calibration was used for quantitation. Results. The effectiveness of screening studies when monitoring food products using the GC-MS/MS method can be significantly elevated by increasing the number of MRM transitions (at least 3), controlling the reference retention time of the substance, and maintaining the ratio of confirmatory ions. To obtain a reliable quantification of trifluralin content in carrots, the use of a matrix-matched calibration is recommended. Limitation. In the study, only carrots were considered as food products. Conclusion. Confirmation of test results is especially important when determining pesticide residues that are not normally found in a given matrix, or when it is suspected that the maximum permissible level may be exceeded. When conducting a screening study and detecting a food contaminant, contamination of the product can only be reported in advance. Next, a confirmatory analysis is required using a validated quantitative method, including an appropriate calibration procedure. In quantitative analysis, the presence of matrix sample components can cause problems due to sample suppression/enhancement phenomena. Matrix-aware calibration has been shown to be effective in compensating for matrix effects.

Simultaneous and High-Throughput Analytical Strategy of 30 Fluorinated Emerging Pollutants Using UHPLC-MS/MS in the Shrimp Aquaculture System.

This study established novel and high-throughput strategies for the simultaneous analysis of 30 fluorinated emerging pollutants in different matrices from the shrimp aquaculture system in eastern China using UHPLC-MS/MS. The parameters of SPE for analysis of water samples and of QuEChERS methods for sediment and shrimp samples were optimized to allow the simultaneous detection and quantitation of 17 per- and polyfluoroalkyl substances (PFASs) and 13 fluoroquinolones (FQs). Under the optimal conditions, the limits of detection of 30 pollutants for water, sediment, and shrimp samples were 0.01-0.30 ng/L, 0.01-0.22 μg/kg, and 0.01-0.23 μg/kg, respectively, while the limits of quantification were 0.04-1.00 ng/L, 0.03-0.73 μg/kg, and 0.03-0.76 μg/kg, with satisfactory recoveries and intra-day precision. The developed methods were successfully applied to the analysis of multiple samples collected from aquaculture ponds in eastern China. PFASs were detected in all samples with concentration ranges of 0.18-0.77 μg/L in water, 0.13-1.41 μg/kg (dry weight) in sediment, and 0.09-0.96 μg/kg (wet weight) in shrimp, respectively. Only two FQs, ciprofloxacin and enrofloxacin, were found in the sediment and shrimp. In general, this study provides valuable insights into the prevalence of fluorinated emerging contaminants, assisting in the monitoring and control of emerging contaminants in aquatic foods.

Levels of chlorpyrifos, ethion, lambda-cyhalothrin, pendimethlin and triazophos pesticide residues in vegetables

Keeping in view the adverse effects of pesticides, due to their excessive uses in crops and storages, a representative study was conducted to evaluate the presence of pesticide residues in vegetables for most frequently used pesticides in the state of Haryana in India. In all, a variety of vegetables were collected as samples from farmers as well as markets located in twenty one districts of Haryana, India for the period of eight years. The extraction of pesticides from vegetable samples was done using QuEChERS method and analysis for commonly used pesticides was done using Gas chromatography–mass spectrometry (GCMS). The analysis of samples showed that approximately one-third of samples were found with detectable presence of pesticide residues. More importantly, the presence of some banned or withdrawn pesticides such as DDT isomers, endosulphan. Furthermore, approximately 40 % of the analyzed samples contained pesticide residues at or below maximum residue level (MRLs) and 16 % of analyzed samples contained pesticide residues above MRLs in terms of commodity groups. Furthermore, residues of Chlorpyrifos were found most often exceeding the Food Safety and Standards Authority of India (FSSAI). Ethion, lambda-cyhalothrin, pendimethlin and triazophos were other pesticides with detected value higher than specified MRL values. Pesticides occurrence in large number of samples need to be "alarming and forcing matter to take appropriate action" to the cause of public health. This study may provide new directions for the application, management and control of pesticides used by farmers.

HPLC-MS/MS and ICP-MS for Evaluation of Mycotoxins and Heavy Metals in Edible Insects and Their Defatted Cakes Resulting from Supercritical Fluid Extraction.

Edible Insects (EIs) are an alternative source of bioactive compounds such as proteins or fatty acids and micronutrients as vitamins or minerals, thus showing potential to replace traditional foodstuffs in an economical and environmentally friendly way. Nonetheless, EIs can accumulate hazardous chemicals such as mycotoxins and heavy metals. The aim of the present study is to determine mycotoxins and heavy metal content in raw insect samples and those resulting products obtained after supercritical fluid extraction (SFE). Insect samples included Acheta domesticus (cricket) meal, Tenebrio molitor (mealworm) meal, Alphitobius diaperinus (buffalo worm), and Locusta migratoria (locust). For this purpose, a QuEChERS method followed by LC-MS/MS analysis was optimized with good results for the analysis of mycotoxins, principally Aflatoxins (AFs), Ochratoxin A (OTA), and Enniatins (ENNs). In contrast, heavy metals (As, Cd, Hg, Pb) were determined by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The results obtained revealed that Locust was positive for AFG2 at a level of 115.5 μg/kg, and mealworm was only contaminated with OTA at 58.1 μg/kg. Emerging mycotoxins (ENNA, ENNA1, ENNB, and ENNB1) were detected at lower levels < 2.2 µg/Kg. Concerning heavy metals, limits exceeding regulation were detected for Cd in the insect species studied, with levels up to 219 μg/kg, and for Pb in crickets (100.3 μg/kg). Finally, the analysis of the post-extraction solids after SFE processing revealed that heavy metals remained in the resulting SFE cakes, while mycotoxins were detected at negligible levels (up to 1.3 µg/Kg).

Monitoring and Risk Assessment of Multi-Pesticide Residues in Apples: A Focus on Consumer Safety

Pesticide residues in human diets pose significant health hazards, particularly for vulnerable populations such as infants and children. This study aimed to determine pesticide residues in apples and to assess the cumulatively chronic risk posed to adult and child consumers from simultaneous exposure to multiple residues. During the 2022–2023 harvest seasons, 100 apple samples from Turkey were analyzed for the presence of 225 different pesticide residues. Pesticide extraction was performed using the QuEChERS method, followed by detection through liquid chromatography coupled with tandem mass spectrometry. Fifteen distinct pesticides (ten insecticides and five fungicides) were detected in 64 out of the 100 apple samples analyzed. Eleven samples contained pesticide residues that exceeded the maximum residue limit (MRL) set by the Turkish Food Codex and the European Union. Thiophanate-methyl was the most frequently detected pesticide (34%) in apples, with concentrations ranging from 0.012 to 0.108 mg kg−1, all of which were well below the MRL of 0.5 mg kg−1. Other commonly detected residues included chlorantraniliprole (28%), acetamiprid (24%), sulfoxaflor (22%), bifenazate (18%), indoxacarb (13%), diflubenzuron (12%), and carbendazim (10%). Under a worst-case scenario, the hazard index (HI) values for adults and children were 0.85% and 2.60%, respectively, indicating that these values remain significantly below the risk threshold of 100%, suggesting no associated health risks from apple consumption. However, regular monitoring of pesticide residues in fresh fruits and vegetables remains critically important.

Levels of organochlorine pesticides in the chewable and leftover parts of the khat (Catha edulis) sold in local markets of Jimma Town, Southwest Ethiopia

ABSTRACT This study aimed to determine the residual levels of organochlorine pesticides (OCPs) in chewable (tender leaves) and leftovers (mature leaves) of khat sold in local markets in Jimma town, southwest Ethiopia. Samples were collected from various local khat market places in Jimma town, based on their growing origin. A modified QuEChERS method was used to extract pesticides from the samples before their analysis by GC‒MS. The findings indicated that p,p’-dichlorodiphenyldichloroethylene (p,p’-DDE) and p,p’-dichlorodiphenyltrichloroethane (p,p’-DDT) were detected in 88.3% and 76.6% of chewable samples, and in 86% and 69% of khat leftovers samples. The p,p’-DDE and p,p’-DDT levels found in chewable khat ranged from 10.12–45.39 and 8.53–34.15 µg/kg, respectively. While in leftover khat they ranged from 30.12–45.04 and 6.73–32.16 µg/kg, respectively. It was found that the concentration of p,p’-DDE is greater than its precursor compound p,p’-DDT for each sample, indicating past use of DDT in the study area. None of the detected analytes exceeded the maximum residue level (MRL) values established by the FAO/WHO or European Commission (EC) of 50 µg/kg. However, no information is available regarding these pesticides’ collective and synergetic negative impacts on consumers.

Optimization of a Modified QuEChERS Method of Experimental Design for Vitamin B2, B3, B6 and B9 in Powder Formula Milk by HPLC/DAD

The purpose of this work is to use HPLC/DAD to ascertain the best extraction and cleanup conditions for various forms of vitamin B in powder formula milk. The QuEChERS method’s key variables were optimized using a Box-Behnken design with 3-level 4-variable and Minimum-Run Resolution IV Screening Design. Following the selection of the best experimental setup, the suggested approach was applied to quantify four vitamins B (B2, B3, B6, and B9) in powder formula milk matrix by HPLC/PDA in accordance with AOAC and ICH guidelines. When taking into account the performance standards given in this guideline, the approach presented recovery between 83.55 and 108.43 for 4 B vitamins, which is adequate. The intra-day and inter day percentage relative standard deviations were 1.66 to 2.75% and 0.47 to 4.78%, respectively. Furthermore, the technique enabled the determination of low detection limits in less than 25 minutes of analytical time. The proposed method’s excellent accuracy, precision, and efficiency made it acceptable for regular B vitamin analysis when applied to powder formula milk samples. The findings confirmed that the modified QuEChERS technique is appropriate for routinely assessing B vitamin levels in powder formula milk matrix.

Simultaneous determination of some coccidiostat antibiotics in food by liquid chromatography tandem mass spectrometry (LC-MS/MS)

Coccidiostats (anticoccidial antibiotics) are veterinary drugs widely used for the prevention and treatment of coccidiosis, especially in poultry farming. The illegal use of anticoccidial antibiotics, in the wrong dosage and duration, can lead to antibiotic residues in animal products and harm the health of consumers. In this study, a highly sensitive and accurate liquid chromatography-tandem mass spectrometry method was developed for the simultaneous analysis of anticoccidial antibiotics (diclazuril, nicarbazin, robenidin and salinomycin) in food. Samples were extracted using the QuEChERS method with acetonitrile (ACN) as the extraction solvent and cleaned with C18 adsorbent. The cleaned extracts were analyzed on an LC-MS/MS system with a C18 reversed-phase chromatography column (2.1 x 150 mm, 3.5 &amp;micro;m) and corresponding pre-column. The mobile phase used was 0.1% HCOOH in water and methanol (MeOH), the flow rate was 0.5 mL/min. The method had good specificity, the linear range was established in the range of 10-100 ng/mL, the correlation coefficient R2 &amp;gt; 0.998. The method recovery was in the range of 81-109% and the relative standard deviation (RSD%) was in the range of 1.77-10.13% for milk and meat samples. The limit of quantification and limit of detection of the method for four coccidiostat antibiotics were 3.0 &amp;micro;g/kg and 10 &amp;micro;g/kg, respectively. The method was applied to analyze the content of these four antibiotics in 31 food samples (meat and meat products, milk and dairy products) randomly purchased in Hanoi. The results did not detect four coccidiostat antibiotics in all 31 samples, initially showing that the residual contamination of coccidiostat antibiotics is basically safely controlled.

Development of an advanced analytical technique for detecting multiple pesticide residues in vegetables through liquid chromatography tandem mass spectroscopy (LC-MS/MS)

A comprehensive LC-MS/MS method, which employs Positive Electrospray Ionization (PEI) and Multiple Reaction Monitoring (MRM) was developed for the simultaneous determination of 35 pesticides belonging to various chemical classes in tomato, brinjal, chili, and okra samples. Extraction was facilitated using a modified QuEChERS method, which allows efficient sample analysis in a single run. Calibration curves for each pesticide exhibited linearity within the concentration range of 0.0025 to 0.1 µg mL−1, with correlation coefficients ranging from 0.993 to 0.999. Mean recoveries at five fortification levels (0.01 to 0.5 µg kg−1) ranged from 80 to 90%, demonstrating satisfactory precision (RSD < 20%). The matrix effects, mitigated through an optimized cleanup process, were observed within the range of 6.42% to 19.52%. The developed method having the limit of quantification of 0.01 mg kg−1 for all 35 pesticides, proved to be highly sensitive and rapid for multi-residue estimation in diverse vegetable samples. Subsequently, the method was used to analyze the market samples from Varanasi, India, which revealed the presence of pesticides like Chlorpyrifos, Chlorantraniliproleand Indoxacarb in tomato, brinjal, chili and okra. Therefore, the method could be considered as a robust tool for monitoring pesticide residues in vegetables, aiding in quality assessment and regulatory compliance in the agriculture sector.

Determination of drugs of abuse and metabolites in plasma microsamples by LC-MS/MS after microQuEChERS extraction.

Aim: Identifying drugs of abuse and their metabolites in plasma is vital in both forensic and clinical toxicology. While the QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method offers an efficient approach to sample preparation, its application is complex due to the wide-ranging properties of target analytes and the challenges posed by biological matrix interferences. This study aims to develop a microQuEChERS approach for the quantification of 14 drugs of abuse and metabolites utilizing minimal sample and solvent volumes.Methods: The microQuEChERS method involved using 10μl plasma samples, 25mg of a salt mixture and 150μl of acetonitrile. Extracts were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS), with a 7.5min run. The assay was validated according to bioanalytical guidelines.Results: The accuracy was 96.8-112.4%. The within-assay precision was within 2.0-8.9% and the between-assay precision was within 3.2-8.2%. Matrix effects were found to range from -5.7 to 13.5%. The extraction yield was higher than 74.7%.Conclusion: This study described a microQuEChERS sample preparation approach for determining drugs of abuse and metabolites using plasma microsamples and LC-MS/MS. The approach is efficient, environmentally friendly and suitable for scenarios with limited amounts of biological samples.

Multi-residue analysis method based on QuEChERS followed by ultra-high performance liquid chromatography coupled with diode-array detector for pesticides in human serum and breast milk.

Background: Maternal fluids play a key role in the risk assessment regarding early life pesticide exposure as the chemicals can transfer to neonate through prenatal exposure and lactation.Aim: A developed UHPLC-DAD and modified QuChERS methods were validated for human serum and breast milk. Matrix effect of the biological samples were evaluated.Methods & results: Serum was extracted by unbuffered QuChERS method while breast milk was extracted by citrate buffered method with addition of hexane. Remaining lipid in breast milk extract was later removed using lipid-removal sorbent. Sample matrices caused huge impacted on low-sensitivity pesticides.Conclusion: The modified QuEChERS methods coupled with UHPLC-DAD were fully validated. Application in paired-serum and breast milk samples revealed 6 detected pesticides.

Comparison of the presence of high production volume chemicals in farmed and wild fish highly consumed in catalonia and their risk assessment

The decline in fish populations and the depletion of marine resources have sparked concerns about sustainable fish production, driving the innovation of new aquaculture methods. While some argue that wild fish are healthier than farmed fish due to less exposure to contaminants and pathogens, wild fish can accumulate contaminants from more contaminated water sources. The slower growth of wild fish and their longer exposure to the environment may contribute to higher pollutant levels in fish tissues. In this study, we focus on 25 contaminants considered as high production volume chemicals (HPVCs), such as organophosphate esters (OPEs), benzothiazoles (BTs), benzosulfonamides (BSAs) and phthalates (PAEs). The compounds were extracted from the edible part of the fish using the QuEChERS method and analysed by gas chromatography-tandem mass spectrometry.A total of 74 samples were analysed from three of the most commonly consumed species in Catalonia, Spain (turbot, sea bass and sea bream). Two samples of each species were collected each month, one form farmed and one from wild origin. In general, the compounds were found in all the samples in a wide concentrations range, although no significant differences were observed between the mean concentration of wild and farmed samples. Although similar mean concentrations for the OPEs, BTs and BSAs were found between farmed and wild origin samples, PAEs were more frequently detected in farmed samples. Di-n-octyl phthalate and diethyl phthalate showed the highest concentrations in all fish samples, with values up to 19505 and 17605 ng g−1 (d.w.), in sea bass and sea bream, respectively. Di-(2-ethylexyl)-adipate proved to be the most relevant carcinogenic compound, with no associated health risk. Despite the detection of the studied HPVCs, no health risk was associated with the consumption of these three fish species.

SWIEET-a salt-free alternative to QuEChERS.

The efficient extraction of various analytes from a wide spectrum of matrices with organic solvents is still a great challenge in analytical chemistry. Especially polar and charged compounds are hard to extract in combination with neutral analytes of intermediate to low polarity. The QuEChERS method is often chosen and has been adapted not only to the analysis of food samples, but also to environmental matrices (soil, wastewater) or biota. In this study, we overcome major drawbacks of QuEChERS such as low recoveries of charged analytes and impairment of downstream analysis by high salt loads. The new extraction method, applicable to liquid and solid samples, is called SWIEET (sugar water isopropanol ethyl nitrile extraction technique). Phase separation of the otherwise miscible extraction solvents water and acetonitrile is achieved by sugaring-out instead of salting-out. Extraction efficiencies were greatly improved by adding isopropanol to the acetonitrile phase. The concentrations of the additives glucose and isopropanol, as well as temperature, were optimized by a design of experiment. Further improvement was achieved through electro- or double-extractions. For all sample types tested (surface water, wastewater treatment plant effluent, tomato, soil, and oats), recoveries and precision were higher with SWIEET than with the established QuEChERS method. From wastewater treatment plant effluent, 75% recovery on average were achieved with our SWIEET method compared to 37% with QuEChERS for a model analyte mixture with polarities of logDpH7 = - 5.7 - 3.5. Higher recoveries and lower standard deviations compared to QuEChERS were achieved especially for polar and charged analytes such as metformin. Handling proved to be easy, since there was no additional solid phase and no tedious weighing of salts.

A QuEChERS method based on octadecyl-bonded hectorite for the determination of ten mycotoxins in yak ghee.

To develop a clean-up material suitable for high-fat food matrices for detecting mycotoxins in yak ghee, an octadecyl-bonded hectorite (Hectorite@NHCO(CH2)17CH3) was synthesized through multi-step chemical reactions. A modified QuEChERS-HPLC-MS/MS method for detecting ten mycotoxins in sesame oil in yak ghee was established using Hectorite@NHCO(CH2)17CH3 as clean-up agent. It involved extracting mycotoxin contaminants using acidified acetonitrile and employing the Hectorite@NHCO(CH2)17CH3 to remove interfering substances from the extract. The purified samples were then analyzed using HPLC-MS/MS. Within a linear range of 1.0-500μg/kg, there was a good linear relationship between the quantification ion peak area of the target analytes and the corresponding concentrations (R2 ≥ 0.9991). The limit of detection (LOD) ranged from 0.10μg/kg to 18.62μg/kg and the limit of quantitation (LOQ) ranged 0.32-62.07μg/kg. The recoveries at low, medium and high concentrations (25, 100 and 500μg/kg) ranged from 72.2% to 113.9%, with relative standard deviations (RSD) between 3.2% and 17.5%. The intra-day and inter-day precision met experimental requirements. The proposed method was characterized by a high accuracy and precision, and it could cater to the current demand for detecting ten mycotoxins in yak ghee.

Analysis of Pesticide Residue in Fruit Using the QuEChERS Method Coupled With LC-MS/MS Detection

Analysis of Pesticide Residue in Fruit Using the QuEChERS Method Coupled With LC-MS/MS Detection