Multiresidue Method Research Articles

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.

Determining personal exposure to high production volume chemicals (HPVCs) and polycyclic aromatic hydrocarbons (PAHs) with silicone wristbands: A pilot study

High production volume chemicals (HPVCs) and polycyclic aromatic hydrocarbons (PAHs) are semi-volatile organic compounds (semi-VOCs) of great environmental concern because of their presence worldwide and health problems resulting from long-term exposure to some of them. It is essential to have robust analytical methods to monitor the concentrations of these compounds not only in environmental samples but also individual exposure. In this pilot study we develop and validate a multiresidue analytical method based on ultrasound-assisted extraction and gas-chromatography mass spectrometry for the simultaneous determination of 56 semi-VOCs using silicone wristbands (SWBs) as personal passive samplers. The developed method provided recoveries between 43% and 114% on sampled SWBs and method detection and quantification limits in the range of 0.1–35 ng/g and 0.3–119 ng/g, respectively. A preliminary study was performed with a small group of adults living in the industrial city of Tarragona (north-eastern Spain) to evaluate the applicability of SWBs for monitoring individual exposure to the studied HPVCs and PAHs. Benzothiazoles, benzenesulfonamides, UV stabilisers and phenolic antioxidants were determined for the first time in SWBs. Phthalates (PAEs), stood out above the rest, accounting for 52% of the total concentrations. Diethylhexyl phthalate was the compound found at the highest concentrations with values between 1.1 and 82 μg/g. Carcinogenic and non-carcinogenic dermal risk assessment was performed for adults and considering two scenarios (low and high). PAHs were the compounds with the highest carcinogenic and non-carcinogenic dermal risk regardless of the exposure scenario. The second family of compounds that contributed the most to the total risk were PAEs but high punctual concentrations of these compounds caused significant differences between exposure scenarios.

Development and validation of multiresidue analysis method for biomonitoring of pesticides and metabolites in human blood and urine by LC-QToF-MS

The widespread use of pesticides and their consequential presence in the environment is a growing concern due to the harmful health effects associated with pesticide exposure. For clinical and toxicology laboratories, a method for simultaneously determining these compounds and their metabolic products in body fluids, such as blood and urine, is important. In the present study, a rapid, sensitive and simultaneous LC-QToF-MS method for detecting multiclass pesticides and metabolites in blood and urine samples has been developed and validated. Four sample preparation procedures, protein precipitation and three different variants of QuEChERS-based extraction were evaluated to find a suitable, simple, and effective sample pretreatment technique. The final optimized sample preparation method (acetonitrile; 400 μl, MgSO4; 40 mg and NaCl; 10 mg) was validated for accuracy, precision, matrix effect, recovery, stability, carryover, and dilution integrity. Analyte recoveries ranged from 75.40 to 113.54 % while accuracy was evaluated in the range of 71.41–108.26 % and precision (%RSD) in the range of 0.01 %–16.85 %. The limit of quantification (LOQ) for all compounds was established in the range of 0.82–7.05 ng mL-1. The developed reliable, robust, and sensitive method was successfully applied for the quantification of target pesticides and metabolites in human blood and urine samples. Evaluated samples resulted in detection of eleven analytes (seven pesticides and four metabolites).

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.

Extraction and detection of sulfonamide antibiotics in milk using magnetic solid-phase adsorbent based on molecular mechanics and DFT calculations

Based on the foundation of calculations in molecular mechanics and density functional theory (DFT) for in-depth mechanistic studies, this paper proposes the sample multi-residue analysis method of five common sulfonamide antibiotics (SAs) in milk. Fe3O4 nanoparticles modified magnetic graphene oxide nanoribbons (Mag-GONRs) with superior dispersibility and dispersion stability, were developed and firstly utilized to rapidly extract residual SAs from milk. Therefore, various SAs in complex samples could be simultaneously determined solely by high performance liquid chromatography-ultraviolet detector (HPLC-UV) without the need for complicated pretreatment processes. In order to obtain satisfactory extraction efficiency, indispensable investigation and optimization were conducted on some parameters influencing the extraction efficiency. And the extracted SAs were determined by. Good linearity for all analytes was achieved with appropriate correlation coefficients (R2 higher than 0.9978). The limits of detection ranged from 0.060 to 0.075 ng·mL−1. Recoveries of the sulfonamides in spiked milk samples were between 79.6 % and 114.6 %, with relative standard deviations within 12 %. Interestingly, with the assistant of computational chemistry, the efficient extraction of Mag-GONRs onto SAs has been validated at the molecular and quantum levels, further elucidating the adsorption mechanism based on non-covalent interactions. In the context of theoretical research and experimental results mutually supporting each other, a practical detection method with actual application value has been proposed in monitoring the residual sulfonamides in milk by the common devices.

A Comprehensive Review of Pests, Pesticides and Residue Detection Techniques in Mushroom

Mushrooms are valued for their dietary benefits and medicinal properties, being rich in proteins, minerals, vitamins, fiber, and essential amino acids. They offer significant health benefits, including the prevention of hypercholesterolemia and cardiovascular diseases, and possess antitumor, antiviral, antihypertensive, anti-inflammatory, and immunomodulating properties. Global mushroom production has seen substantial growth, particularly in Asia. However, mushroom cultivation is challenged by various insect pests, leading to significant crop losses. Pesticides are frequently applied to control pests in mushroom cultivation, but their use can lead to the presence of pesticide residues in the mushrooms, raising concerns about food safety. To detect these low levels of residues, multiresidue analytical methods are crucial. Among these, the QuEChERS method stands out as the most commonly used due to its sensitivity, selectivity, and accuracy in determining multiple pesticide residues simultaneously. These methods are capable of identifying various pesticide compounds in a single analysis, effectively addressing the specific biological characteristics of mushrooms. The maximum residue levels (MRLs) for pesticide residues in mushrooms differ, with strict guidelines enforced by regulatory authorities. This paper provides a comprehensive review of the pests that affect mushroom cultivation, the pesticides utilized, and the analytical techniques developed for the detection of pesticide residues in mushrooms.

Simultaneous determination of phenothiazine drugs and their metabolites residues in animal derived foods by high performance liquid chromatography tandem mass spectrometry

Due to their potential entry into the human body via the food chain, phenothiazine drugs and their metabolites pose specific health hazards, making their detection in edible tissues of paramount importance. In this research endeavor, a highly sensitive multi-residue analytical method has been devised for the detection of phenothiazine drugs and their metabolites in animal-derived food products, utilizing high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS). The preparation of samples involved the use of 1% formic acid in acetonitrile as the extraction solvent following sample weighing, with multiple extraction steps diligently performed to ensure optimal outcomes. The sample, post-extraction, was directly introduced into the purification column, yielding significant time savings and rendering the process more environmentally sustainable. This procedural step effectively eliminated interfering substances from the sample matrix, including proteins, salts, and phospholipids. Analysis of the extracted samples was conducted through HPLC-MS/MS, employing an electrospray ionization (ESI) ion source. A comprehensive panel of 20 phenothiazine drugs and their metabolites was successfully resolved within a mere 10-min chromatographic run. A robust linear correlation (R2 ≥ 0.99) was attained within a judiciously chosen range of concentrations. Method validation was meticulously conducted across multiple animal species, including trout, white shrimp, pork, beef and chicken. The developed analytical method has been effectively deployed for the screening and quantification of phenothiazine drugs in real-world samples sourced from commercial livestock and aquatic products.

Development and validation of a multiresidue method for the determination of antibiotic residues in crawfish using LCMS/MS

ABSTRACT This study developed a rapid multi-class method for determining 29 antibiotic residues in crawfish using liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. A quick and affordable extraction method was employed, and sample preparation was performed using a modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) technique. The extraction process involved adding acetonitrile to crawfish samples. The sample was homogenised with a solution of sodium citrate buffer and sodium EDTA, followed by a cleanup step. The method was validated according to European Union (EU) guidelines 2002/657/EC. The limit of quantitation (LOQ) for all antibiotics was 5 µg/kg, except for flumequine and trimethoprim, which had LOQs of 2.5 µg/kg. The LOQ for the tetracycline group was 25 µg/kg, and for chloramphenicol, it was 0.015 µg/kg. The average recoveries at different concentration levels varied between 60–120%. The precision, expressed as repeatability and reproducibility, was calculated to be less than 16%. Thirty crawfish samples collected from local Egyptian market were monitored for antibiotic residues. The results revealed contamination with antibiotics belonging to three different groups. Of the thirty samples, 27% were contaminated with ciprofloxacin and enrofloxacin, 17% with chlortetracycline and oxytetracycline, 7% with oxolinic acid, and 3% with sulphamethazine. The applicability of the developed method was proven through successful proficiency testing. The developed method met performance criteria and is suitable for monitoring these antibiotics in crawfish.

Multiclass Analysis for the Determination of Pharmaceuticals and Their Main Metabolites in Leafy and Root Vegetables.

The irrigation of soils with reclaimed contaminated wastewater or its amendment with sewage sludge contributes to the uptake of pharmaceuticals by vegetables growing in the soil. A multiresidue method has been devised to determine five pharmaceuticals and nine of their main metabolites in leafy and root vegetables. The method employs ultrasound-assisted extraction, clean-up via dispersive solid-phase extraction, and analysis through liquid chromatography-tandem mass spectrometry. Box-Behnken design was used to refine variables such as extraction solvent volume, time of extraction, number of extraction cycles, and the type and amount of d-SPE sorbent. The method achieved linearity (R2) greater than 0.994, precision (relative standard deviation) under 16% for most compounds, and detection limits ranging from 0.007 to 2.25 ng g-1 dry weight. This method was applied to a leafy vegetable (lettuce) and to a root vegetable (carrot) sourced from a local market. Parent compounds were detected at higher concentrations than their metabolites, with the exception of carbamazepine-10,11-epoxide.

Analysis of chlordecone and its transformation products in environmental waters by a new SPME-GC-MS method and comparison with LLE-GC-MS/MS and LLE-LC-MS/MS: A case study in the French West Indies

Among the numerous organochlorines (OCs) applied in the French West Indies (FWI), chlordecone (hydrated form C10Cl10O2H2; CLD) still causes major environmental pollution nowadays. A recent report revealed the unexpected presence in FWI environment of transformation products (TPs) of CLD not routinely monitored due to a lack of commercial standards. Here, we present a method for surface waters and groundwaters to analyze CLD, its main TPs (hydroCLDs, chlordecol (CLDOH), 10-monohydroCLDOH and polychloroindenes) and other OCs. We developed an SPME-GC-SIM/MS method with a PDMS-DVB fiber. Since CLDOH-d commonly used as internal standard (IS) proved unsuitable, we synthesized several IS candidates, and finally identified 10-monohydro-5-methyl-chlordecol as a satisfactory IS for CLDOH and 10-monohydroCLDOH avoiding the use of 13C-labelled analogue. LODs for CLD and its TPs varied from 0.3 to 10 ng/L, equal to or below LODs of the two laboratories, BRGM (the French geological survey) and LDA26 (one of the French Departmental Analytical Laboratories), requested in FWI pollution monitoring that used liquid-liquid extractions and advanced facilities (LLE-GC‐MS/MS and LLE-LC-MS/MS methods, respectively). Then, we extended the multi-residue method to 30 OCs (CLD and its TPs, mirex, β-HCH, lindane, dieldrin, aldrin, HCB, hexachlorobutadiene, TCE, PCE) and applied it to 30 surface and ground waters from FWI. While CLD, 8- and 10-monohydroCLD, CLDOH, 10-monohydroCLDOH, dieldrin, and β-HCH were detected and quantified, pentachloroindene, another CLD TP, was sporadically found in trace levels. A comparison with BRGM and LDA26 confirmed the interest of the SPME method. Results suggested an underestimation of CLDOH and an overestimation of high CLD concentrations with one of the currently used routine protocol. In light of these findings, previous temporal monitoring of environmental waters in FWI were re-examined and revealed some atypical values, which may indeed be due to analytical bias. These discrepancies call for intensified efforts to reliably quantify CLD and its TPs.

Higher early than late-season residue load of pesticides in honey bee bread in Slovakia

Bees are often exposed to pesticide residues during their foraging trips in agricultural landscapes. The analysis of in-hive stored pollen reflects the spectrum of visited plants and can be almost used to link the exposure to pesticides.In the current study, bee bread samples were collected in May and July from 17 sites located in southern Slovakia. Samples were analysed using a multi-residue pesticide analysis method for a broad spectrum of active substances and microscopic for pollen identification.Our results revealed a bee bread contamination with 19 different active substances, with fungicides being predominant. Sixteen of them are authorized in the EU, but chlorpyrifos, chlorpyrifos-methyl, and chloridazon are not. The highest concentrations for pendimethalin (1400 µg/kg), fluazifop-butyl (640 µg/kg), fenpropidin (520 µg/kg), fluopyram (130 µg/kg), and difenoconazole (95 µg/kg) were detected. The total residue load in bee bread sampled in the early season (May) was significantly higher than in the late season (July). The mean residue load of insecticides analysed in July comprised 46% of May’s load, which is alarming due to the importance of bee bread in the diet for winter-rearing bees. Moreover, results from both sampling periods showed that fungicides were positively associated with plant families Apiaceae and Papaveraceae and herbicides with Aceraceae, Salicaceae, and Brassica-type/Brassicaceae.Hence, bee bread can be considered a suitable matrix and a good bio-indicator reflecting honey bee exposure to pesticides over the season.

Improved efficiency of ion trapping time-of-flight mass spectrometry for the analysis of pesticide residues and mycotoxins at trace levels in baby food

The analysis of pesticide residues and mycotoxins in baby food demands exceptionally low limits of quantitation, necessitating the use of highly sensitive instruments capable of conducting trace analyses. High-resolution instruments typically fail to detect such low levels. However, the latest advancements in liquid time-of-flight technology, when coupled with ion trapping, enable ion enrichment, thereby improving detection levels. This allows for the analysis of these substances at low concentration levels, benefiting from enhanced mass accuracy. Additionally, the use of mass accuracy data helped eliminate matrix interferences, thereby enabling high-confidence identification. We developed a multi-residue method to analyse 219 pesticide residues and 9 mycotoxin residues in baby food matrices. Utilizing a QuEChERS-based extraction method, the samples were then analysed using an LC-ZenoTOF 7600 system with mass window screening acquisition. For pesticides, the limit of quantitation was 0.001–0.003 mg/kg for 81 % of the evaluated compounds, 0.005 mg/kg for 13 %, 0.010 mg/kg for 4 % and 0.020–0.030 for 2 %; good linearities were obtained at these levels. Apparent recoveries were evaluated at 0.003, 0.005, and 0.010 mg/kg. At the lowest recovery level, 93 % of compounds showed recoveries between 70 and 120 %. The rest of the compounds were in the range of 63–129 %, with relative standard deviation values below 20 %. For mycotoxins, the limits of quantitation ranged from 0.0001 to 0.100 mg/kg, with matrix-matched concentrations assessed within this range. Recoveries were evaluated at low concentration range (0.001–0.003 mg/kg) and high range (0.020–0.050) with apparent recoveries values between 92 and 140 %. Finally, a total of 31 commercial baby food samples were analysed using this method. The results indicated that 16 samples contained pesticide residues, while two samples were found to have mycotoxins.

Determination of pesticide residues in urine by chromatography-mass spectrometry: methods and applications.

Pollution has emerged as a significant threat to humanity, necessitating a thorough evaluation of its impacts. As a result, various methods for human biomonitoring have been proposed as vital tools for assessing, managing, and mitigating exposure risks. Among these methods, urine stands out as the most commonly analyzed biological sample and the primary matrix for biomonitoring studies. This review concentrates on exploring the literature concerning residual pesticide determination in urine, utilizing liquid and gas chromatography coupled with mass spectrometry, and its practical applications. The examination focused on methods developed since 2010. Additionally, applications reported between 2015 and 2022 were thoroughly reviewed, utilizing Web of Science as a primary resource. Recent advancements in chromatography-mass spectrometry technology have significantly enhanced the development of multi-residue methods. These determinations are now capable of simultaneously detecting numerous pesticide residues from various chemical and use classes. Furthermore, these methods encompass analytes from a variety of environmental contaminants, offering a comprehensive approach to biomonitoring. These methodologies have been employed across diverse perspectives, including toxicological studies, assessing pesticide exposure in the general population, occupational exposure among farmers, pest control workers, horticulturists, and florists, as well as investigating consequences during pregnancy and childhood, neurodevelopmental impacts, and reproductive disorders. Such strategies were essential in examining the health risks associated with exposure to complex mixtures, including pesticides and other relevant compounds, thereby painting a broader and more accurate picture of human exposure. Moreover, the implementation of integrated strategies, involving international research initiatives and biomonitoring programs, is crucial to optimize resource utilization, enhancing efficiency in health risk assessment.

Nutritional Composition and Chemical Safety of Wagashi Gassirè Cheese Sold in the Southern Benin Markets

In this study, the nutritional composition and the chemical safety of Wagashi Gassirè (WG) cheese sold in southern Benin markets were assessed. For this purpose, 15 WG were analysed for fatty acids, essential minerals, and chemical hazards (dioxins, aflatoxin M1 (AFM1), biogenic amines, metals, antibiotic and pesticide residues). The risks related to arsenic, lead, aluminium, AFM1, histamine, and tyramine were calculated using the methods recommended by the European Food Safety Authority. Oleic, palmitic and stearic acids, calcium, and phosphorus were the main fatty acids and minerals detected. Lead (0.08 ± 0.06 mg/kg) and AFM1 (0.3 ± 0.0 µg/kg) were detected in all samples and exceeded the maximum level set by the international standard. Cadaverine and tyramine were the main biogenic amines found. No pesticide residues were detected using a multi-residue method targeting compounds. Residues of quinolones, tetracyclines, and colistin antibiotics were also detected. The calculated chronic exposure indicated no public health concern for the chemical contaminants targeted. Moreover, the average cancer risk related to AFM1 intake was 3 × 10−4 cases/105 persons/year for the Benin population through WG consumption. This study contributes to the nutritional characterization of WG and identifies lead and AFM1 as the most relevant chemical hazards of this product.

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.Graphical

Improved analysis of 230 pesticide residues in three fermented soy products by using automated one-step accelerated solvent extraction coupled with GC–MS/MS

Consumer concerns over healthy diets are increasing as a result of the toxicity and persistence of pesticide residues in foodstuffs. Developing sensitive and high-throughput monitoring techniques for these trace residues is seen as an essential step in ensuring food safety. An automatic and sensitive multi-residue analytical method was developed and validated for the simultaneous determination of 230 compounds, including pesticides and their hazardous metabolites, in fermented soy products. The method included preparing the sample using on-line extraction and clean-up system based on accelerated solvent extraction (ASE), then determining the analytes using GC–MS/MS techniques. The homogenized samples (soy sauce, douchi, and sufu) were automatically extracted at 80 °C and 10.3 MPa and at the same time, in situ cleaned by 300 mg of primary secondary amine (PSA) combined with 20 mg of hydroxylated multi-walled carbon nanotubes in an extraction cell. The method obtained excellent calibration linearity (r > 0.9220) and a satisfactory analysis of the targeted compounds, which were evaluated with matrix-matched calibration standards over the range of 5–500 μg L−1. The limit of detections (LODs) of analytes were in the range of 0.01–1.29 μg kg−1, 0.01–1.39 μg kg−1, and 0.01–1.34 μg kg−1 in soy sauce, douchi, and sufu, respectively. The limit of quantifications (LOQs), which defined as the lowest spiking level, were set at 5.0 μg kg−1. The recoveries were within 70–120 % for over 95 % of the analytes, and the relative standard deviations (RSDs) were below 13.6 %. Moreover, a positive detection rate of 47 % were obtained when the proposed method was used on 15 real fermented soy products. These results suggested that the developed high-throughput method is highly feasible for monitoring of these target analytes in trace level.

Multiresidue analysis of bat guano using GC-MS/MS

Bats are the second largest mammalian order and are an endangered species group with a strong need for contamination monitoring. To facilitate non-invasive monitoring of the ecological burden in bat populations, a multiresidue method for the simultaneous quantification of 119 analytes including pesticides, persistent organic pollutants (POPs), active pharmaceutical ingredients (APIs), polycyclic aromatic hydrocarbons (PAHs), UV blockers, plasticizers, and other emerging pollutants in bat guano with gas chromatography tandem mass spectrometry (GC-MS/MS) was developed. Sample preparation and clean-up were performed with a modified QuEChERS approach based on DIN EN 15662. The method uses 1.00 g bat guano as sample with acetonitrile and water for liquid-liquid extraction. Phase separation is assisted by citrate-buffered salting out agent. For clean-up of the extract, primary secondary amine (PSA) was combined with graphitized carbon black (GCB). The lower limits of quantification (LLOQ) ranged between 2.5 and 250 µg kg−1. Linearity was shown in a concentration range from the respective LLOQs to 1250 µg kg−1. The median of the mean recovery was 102.4%. Precision was tested at three concentrations. Method and injection precision were adequate with a relative standard deviation (RSD) below 20%. Furthermore, the comparative analysis with LC-MS/MS demonstrated the reliability of the results and provided a valuable extension of the analytical scope. As proof of concept, three guano samples from a German nursery roost of Myotis myotis were analysed. The results show a time-dependent change in contaminant concentration, highlighting the strong need for non-invasive contamination monitoring of whole bat populations.Graphical

Analytical Method for Melengestrol Acetate in Livestock Products Using LC-MS/MS

The present study verified that it is possible to analyze melengesterol acetate using the existing multi-residue method. Melengestrol acetate was extracted from livestock products using acidic acetonitrile acidified with acetic acid in the presence of n-hexane and anhydrous sodium sulfate. The crude extracts were cleaned up using an octadecylsilanized silica gel cartridge column. Separation by HPLC was performed using an octadecylsilanized silica gel column with linear gradient elution of 0.1 vol% formic acid and acetonitrile containing 0.1 vol% formic acid. For the determination of the analyte, tandem mass spectrometry with positive ion electrospray ionization was used. In recovery tests using four livestock products fortified with maximum residue limits levels of melengestrol acetate (0.001-0.02 mg/kg), the truenesses ranged from 82% to 100%, and the repeatabilities for the entire procedure ranged from 0.5 RSD% to 5.6 RSD%. In recovery tests using 11 livestock products fortified with 0.0005 mg/kg of melengestrol acetate, the truenesses ranged from 88% to 99%, and the repeatabilities ranged from 1.3 RSD% to 5.4 RSD%. The limit of quantification for melengestrol acetate in livestock products was 0.0005 mg/kg.

Effect of washing method on the reduction of insecticide residues and quality characteristics of sweet cherry fruits

Sweet cherry trees were sprayed with 5 insecticides (acetamiprid, dimethoate, lambda-cyhalothrin, malathion, tau-fluvalinate) at the recommended field doses in this study. Fruits were harvested after the pre-harvested interval for each pesticide completed and then they were immersed into tap water and three different washing solutions (with three different concentrations) for 3 minutes (at 20ºC). Insecticide concentrations were detected with a multi-residual analysis method using LC-MS/MS in Bursa Uludağ University in 2022. Following the treatments, changes in the quality characteristics of fruits were also investigated by quality (colour, texture and fruit cracking rate, water-soluble dry matter) and sensory analysis (fruit and stem colour, firmness, appearance, general acceptability). The results revealed that washing method with tap water during 3 min decreased insecticide residue level by 7-45% depending on insecticide active compound. Higher reduction rates were observed by washing with citric acid (10%), sodium bicarbonate (2.5%) and sodium hydroxide (0.5%). But significant reductions were detected only in lambda-cyhalothrin and malathion residues when compared with the newly harvested fruit samples. Processing factors (PF) of all washing methods were generally lower than 1 except for three treatments. PF values showed variations depending on the type of washing solution and the active compound of insecticides. Although washing with citric acid (10%), sodium bicarbonate (2.5%) and sodium hydroxide (0.5%) solutions caused reduction in residue levels, their negative effects on the quality and sensory characteristics of the fruits cannot be ruled out.

Evaluation of the Health Risk and Distribution Characteristics of Pesticides in Shallow Groundwater, South Korea

In this work, a method of simultaneously analyzing pesticide concentration and assessing its risks was developed. Assessments were conducted to evaluate the distribution characteristics and risks to human health of pesticides in shallow groundwater in agricultural areas. We developed multi-residue analytical methods using liquid chromatography (LC-MS/MS) and gas chromatography–tandem mass spectrometry (GC-MS/MS) to analyze 57 pesticides in groundwater. In addition, risk assessments were performed by setting scenarios considering the routes of pesticide infiltration into groundwater. For the simultaneous analysis of 57 pesticides, the liquid–liquid extraction method was applied twice using dichloromethane under acidic and alkaline conditions. The extract was concentrated and analyzed using LC-MS/MS (41 pesticides) and GC-MS/MS (16 pesticides). The precision and accuracy ranges of the analytical methods were 0.1~12.9% (within ±15%) and 80.3~113.6% (within ±20%), respectively. The limit of quantification was found to range from 0.0004 to 0.0677 μg/L. In total, 57 pesticides were monitored in 200 groundwater wells from 2019 to 2020. Twenty-six pesticides, including metolachlor and imidacloprid, were detected, with an average concentration of 0.0008 μg/L in groundwater. The pesticide types and detection levels differed depending on the survey period and surrounding land. When the risks associated with alachlor, metolachlor, and carbofuran were assessed, their health risks when found in groundwater were evaluated to be negligible (non-carcinogenic risk: less than 10−3, carcinogenic risk: less than 10−6).