Determination of pesticide residues in chilli and Sichuan pepper by high performance liquid chromatography quadrupole time-of-flight mass spectrometry

Determination of twelve neonicotinoid pesticides in chili using an improved QuEChERS method with UPLC-Q-TOF/MS

In this study, a QuEChERS method based on citrate was developed and utilized for the analysis of twelve neonicotinoid pesticides in fresh red chilies, fresh green chilies, and dried chilies, coupled with ultra-high performance liquid chromatography quadrupole time of flight mass spectrometry (UPLC-Q-TOF/MS). In the sample preparation, acetonitrile containing 1% formic acid was used as the extraction solvent. Anhydrous sodium sulfate replaced the traditional anhydrous magnesium sulfate for water removal, effectively eliminating the issues of salt caking. Graphitized carbon black, octadecyl silica, and primary secondary amine were used as cleaning agents. The method showed good sensitivity, with the limits of quantification below 0.03 mg/kg for fresh chilies and below 0.15 mg/kg for dried chilies. Values of matrix effects ranged from -19.5% to 8.4%, and the recovery was 86.9% - 105.2%. The analytical method provided an effective tool for the high throughput detection of neonicotinoid pesticide residues in multiple chili matrices.

Pesticides in the environment: Degradation routes, pesticide transformation products and ecotoxicological considerations

Among rising environmental concerns, emerging contaminants constitute a variety of different chemicals and biological agents. The composition, residence time in environmental media, chemical interactions, and toxicity of emerging contaminants are not fully known, and hence, their regulation becomes problematic. Some of the important groups of emerging contaminants are pesticides and pesticide transformation products (PTPs), which present a considerable obstacle to maintaining and preserving ecosystem health. This review article aims to thoroughly comprehend the occurrence, fate, and ecotoxicological importance of pesticide transformation products (PTPs). The paper provides an overview of pesticides and PTPs as contaminants of emerging concern and discusses the modes of degradation of pesticides, their properties and associated risks. The degradation of pesticides, however, does not lead to complete destruction but can instead lead to the generation of PTPs. The review discusses the properties and toxicity of PTPs and presents the methods available for their detection. Moreover, the present study examines the existing regulatory framework and suggests the need for the development of new technologies for easy, routine detection of PTPs to regulate them effectively in the environment.

Mn-modified porphyrin metal-organic framework mediated colorimetric and photothermal dual-channel probe for sensitive detection of organophosphorus pesticides

Herein, a novel dual-mode probe for organophosphorus pesticides (OPs) colorimetric and photothermal detection was developed based on manganese modified porphyrin metal-organic framework (PCN-224-Mn). PCN-224-Mn had excellent oxidase-like activity and oxidized colorless 3,3,5,5-tetramethylbenzidine (TMB) to blue-green oxidation state TMB (oxTMB), which exhibited high temperature under near-infrared irradiation. l-ascorbate-2-phosphate was hydrolyzed by acid phosphatase to produce ascorbic acid, which weakened colorimetric and photothermal signals by impacting oxTMB generation. The presence of OPs blocked the production of ascorbic acid by irreversibly inhibiting the activity of acid phosphatase, causing the restoration of chromogenic reaction and the increase of temperature. Under the optimal conditions, the probe showed a good linear response to OPs in the concentration range of 5 ∼ 10000 ng/mL, using glyphosate as the analog. The detection limits of glyphosate in colorimetric mode and photothermal mode were 1.47 ng/mL and 2.00 ng/mL, respectively. The probe was successfully used for sensitive identification of OPs residues in tea, brown rice, and wheat flour. This work proposes a simple and reliable colorimetric/photothermal platform for OPs identification, which overcomes the problem that single-mode detection probes are susceptible to external factors, and has broad application potential in the field of food safety.

Improving pesticide residue detection: Immobilized enzyme microreactor embedded in microfluidic paper-based analytical devices

Orientationally immobilized enzyme microreactors (OIMERs), embedded in microfluidic paper-based analytical devices (μPADs) were developed for improved detection of pesticide residues in food. Acetylcholinesterase (AChE) was orientationally immobilized on the reusable Part I of the μPADs, using the specific affinity binding of concanavalin A (Con A) to a glycosyl group on AChE. Using the disposable Part II, facile colorimetric quantification was performed with a smartphone and software, or qualitative detection by a naked-eye visual test. The AChE immobilized in OIMERs not only had improved activity and stability, but also high sensitivity, with a limit of detection as low as (0.007 ± 0.003) μg/mL. The method was used to detect pesticides residues in real vegetable samples; the recovery (88.6-102.7%) showed high reliability for pesticide residues detection in foods. A molecular docking study and an enzyme kinetic analysis were conducted to characterize the mechanism of action of the OIMERs.

Exposure and risk assessment for agricultural workers during chlorothalonil and flubendiamide treatments in pepper fields

Pesticides are indispensable tools in modern agriculture for enhancing crop productivity. However, the inherent toxicity of pesticides raises significant concerns regarding human exposure, particularly among agricultural workers. This study investigated the exposure and associated risks of two commonly used pesticides in open-field pepper cultivation, namely, chlorothalonil and flubendiamide, in the Republic of Korea. We used a comprehensive approach, encompassing dermal and inhalation exposure measurements in agricultural workers during two critical scenarios: mixing/loading and application. Results revealed that during mixing/loading, dermal exposure to chlorothalonil was 3.33 mg (0.0002% of the total active ingredient [a.i.]), while flubendiamide exposure amounted to 0.173 mg (0.0001% of the a.i.). Conversely, dermal exposure increased significantly during application to 648 mg (chlorothalonil) and 93.1 mg (flubendiamide), representing 0.037% and 0.065% of the total a.i., respectively. Inhalation exposure was also evident, with chlorothalonil and flubendiamide exposure levels varying across scenarios. Notably, the risk assessment using the Risk Index (RI) indicated acceptable risk of exposure during mixing/loading but raised concerns during application, where all RIs exceeded 1, signifying potential risk. We suggest implementing additional personal protective equipment (PPE) during pesticide application, such as gowns and lower-body PPE, to mitigate these risks.

Inner filter effect-based upconversion nanosensor for rapid detection of thiram pesticides using upconversion nanoparticles and dithizone-cadmium complexes

Herein, we propose a method for detecting thiram based on the fluorescence inner filter effect using upconversion nanoparticles and dithizone-cadmium complexes (DZ-Cd2+). The ultraviolet absorption of DZ-Cd2+ was in the range of 480-600 nm under alkaline conditions, resulting in fluorescence quenching of the nanoparticles at 540 nm. Thiram had a stronger coordination effect with Cd2+ than dithizone; thus, more thiram-cadmium complex (T-Cd2+) formed when thiram was added, leading to fluorescence recovery at 540 nm. The standard thiram curve was found to have a detection limit of 6.75 ng/mL in the linear range of 0.01-1000 µg/mL. In addition, high-performance liquid chromatography results for detecting thiram in apple samples revealed good application performance. The results demonstrate that the developed method has great potential to detect thiram residues in food.

Determination of multiclass contaminants in chilli powder based on magnetic multiwalled carbon nanotubes and UPLC-QTOF/MS

A multiclass analysis approach was developed using magnetic multiwalled carbon nanotubes sorbents and ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS) for the rapid screening and simultaneous determination of 216 contaminants including 15 mycotoxins, 9 synthetic colourants, and 192 pesticides in chilli powder. The sample preparation process was optimized. The optimal preparation procedure utilized NaCl and NaAc as the salting-out agents, and Fe3O4-MWCNTs as the sorbents, resulting in reduced chemical consumption, improved cleaning performance, and facilitated high-throughput analysis. The proposed method was validated, and satisfactory parameters were obtained. Approximately 85.6% of the target analytes exhibited a weak matrix effect, with the matrix effects falling within the range of 0.8 ∼ 1.2. The method demonstrated acceptable recoveries of the analytes, falling within the range of 62.14%∼119.76% at three fortified levels with relative standard deviations (RSDs) of less than 20%. Additionally, the method's limit of quantification (LOQ) ranged from ranged from 0.50 μg·kg-1 to 49.56 μg·kg-1. The method was further applied for analysis of 27 chilli powder samples, demonstrating its potential for screening and quantification of multiclass contaminants for spices.

Residue behavior and processing factors of thirteen field-applied pesticides during the production of Chinese traditional fermented chopped pepper and chili powder

In this study, the fate, processing factors and relationship with physicochemical properties of thirteen pesticides in field-collected pepper samples during Chinese chopped pepper and chili powder production was systematically studied. The washing, air-drying, chopping and salting and fermentation processes reduced 24.8%-62.8%, 0.9%-26.4%, 25.1%-50.3% and 16.3%-90.0% of thirteen pesticide residues, respectively, while the sun-drying processing increased the residues of eleven pesticides by 1.27-5.19 fold. The PFs of thirteen pesticides were < 1 in chopped pepper production and the PFs of eleven pesticides were more than 1 for chili powder production. The chopped pepper processing efficiency have most negative correlation with octanol-water partition coefficient. In contrast, the chili powder processing efficiency have most positive correlation with vapour pressure. Thus, this study can offer important references for assessment the pesticide residue levels in Chinese traditional fermented chopped pepper and chili powder production from fresh peppers.

High-throughput screening and quantification of pesticides in Lilii Bulbus using ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry

Lilii Bulbus is a notable flower in Chinese cuisine, and has also been used as a Chinese herbal medicine for over 2000 years. This work presents an analytical method for rapidly screening multiple pesticide residues in Lilii Bulbus using ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS). For sample pre-treatment, the QuEChERS method is employed, and targeted MS/MS is adopted for data acquisition. Moreover, a database containing 515 pesticides with accurate mass database and a high-resolution fragment ion spectrum library is established in this work. In addition, the qualitative and quantitative results of the screening method are validated. The results show that within the linear concentration range of 2 to 200 μg L-1, for each pesticide, 89.3% of the pesticides exhibit linear correlation coefficients R2 equal to or exceeding 0.990. The limit of quantification for all pesticides is below 50 μg kg-1. With a recovery of 70% to 120% and RSD ≤ 20% as the satisfactory standards, 387 (75.0%), 411 (79.7%) and 420 (81.4%) pesticides meet the standards at the three addition levels of 10 μg kg-1, 20 μg kg-1, and 100 μg kg-1, respectively. By utilizing the proposed method, pesticide residues in 100 samples are investigated, providing scientific data to ensure the safety of pesticide residues and demonstrating the general applicability of the method for routine monitoring of pesticide residues in Lilii Bulbus.

A review on recent advances in mass spectrometry analysis of harmful contaminants in food

Food safety is a widespread global concern with the emergence of foodborne diseases. Thus, establishing accurate and sensitive detection methods of harmful contaminants in different food matrices is essential to address and prevent the associated health risks. Among various analytical tools, mass spectrometry (MS) can quantify multiple impurities simultaneously due to high resolution and accuracy and can achieve non-target profiling of unknown pollutants in food. Therefore, MS has been widely used for determination of hazardous contaminants [e.g., mycotoxin, pesticide and veterinary drug residues, polychlorinated biphenyls (PCBs), dioxins, acrylamide, perfluorinated compounds (PFCs) and p-Phenylenediamine compounds (PPDs) in food samples]. This work summarizes MS applications in detecting harmful contaminants in food matrices, discusses advantages of MS for food safety study, and provides a perspective on future directions of MS development in food research. With the persistent occurrence of novel contaminants, MS will play a more and more critical role in food analysis.

Recent Advancements in Liquid Chromatographic Techniques to Estimate Pesticide Residues Found in Medicinal Plants around the Globe

In the present review article, different advanced liquid chromatographic techniques and the advanced techniques other than liquid chromatography that are used to estimate the pesticide residues from different plant-based samples are presented. In the beginning of the article, details of pesticides, their health effects and various cell lines used for the related study has been outlined. Afterward, detailed descriptions regarding pesticides classification are inscribed. In the end, recent advancements in the area of analysis of pesticides for herbal drugs are explained. Solid phase micro extraction (SPME) and solid-phase extraction (SPE) are considered as most common method of sample preparation for pesticides and its residual analysis. The most commonly used analytical separation technique for pesticide analysis is liquid chromatography (LC) integrated with mass spectrometry (MS) and MS/MS as Triple Quadrupole Mass Spectrometer (QqQ) for the samples analysis where high level of sensitivity and accuracy is required in quantification.

Aptamer recognition-promoted hybridization chain reaction for amplified label-free and enzyme-free fluorescence analysis of pesticide

Development of high-performance fluorescence sensors for pesticide is highly urgent but remains a grand challenge. It is due to that most of known fluorescence sensors detect pesticides based on enzyme-inhibited strategy, which requires high-price cholinesterase, suffers from serious interference of reductive materials, and can't difference pesticides with each other; the known aptamer-based fluorescence ones entail tool enzymes or nanomaterials to transducer/amplify the signal and demand signalers to be tagged in nucleic acid, which are expensive and intricate. Herein, we develop a novel aptamer-based fluorescence system for label-free, enzyme-free and highly sensitive detection of pesticide (profenofos) based on target-initiated hybridization chain reaction (HCR)-assisted signal amplification and specific intercalation of N-methylmesoporphyrin IX (NMM) in G-quadruplex DNA. Hairpin probe ON1 recognizes profenofos to generate profenofos@ON1 complex, which switches the HCR to yield multiple G-quadruplex DNA, consequently making large numbers of NMM be locked. In comparison with profenofos absence, a sharply improved fluorescence signal was recorded and it was dependent on profenofos dose. Hence, label-free, enzyme-free and highly sensitive detection of profenofos is achieved with limit of detection of 0.085 nM, which compared favorably with or superior to those of known fluorescence methods. Furthermore, the present method was applied to determine the profenofos residue in rice with agreeable result, and will provide more valuable information for guaranteeing the pesticide-related food safety.

Determination of multiple mycotoxins in chili powder using cold-induced liquid-liquid extraction and Fe3O4@MWCNTs-NH2 coupled with UPLC-Q-TOF/MS

Food matrix interference is still a big challenge in analyzing multiclass mycotoxins. Herein, a novel cold-induced liquid-liquid extraction-magnetic solid phase extraction (CI-LLE-MSPE) coupled with ultra-high performance liquid chromatography-quadrupole time of flight mass spectrometry (UPLC-Q-TOF/MS) method was explored for the simultaneous determination of multiple mycotoxins in chili powders. Fe₃O₄@MWCNTs-NH₂ nanomaterials were prepared and characterized, and the factors affecting the MSPE process were investigated. Based on this, the CI-LLE-MSPE-UPLC-Q-TOF/MS method was established for determining ten mycotoxins in chili powders. The proffered technique eliminated the matrix interference effectively and demonstrated strong linearity (0.5-500 µg/kg, R² ≥ 0.999), high sensitivity (limit of quantification was 0.5-1.5 µg/kg), and the recovery was 70.6%-111.7%. The extraction process is simpler than conventional methods, as the adsorbent can be separated using magnets, and reusable adsorbents are beneficial in reducing costs. In addition, the method can provide a valuable reference for pretreatment procedures for other complex matrices.

Evaluation the food safety of cultured fat via detection of residues of adipogenic differentiation cocktail in cultured fat with high performance liquid chromatography and enzyme-linked immunosorbent assay

Cultured fat is inducing adipose progenitor cells (APCs) to differentiate into mature adipocytes for consumption. The traditional adipogenic differentiation cocktail, including insulin, dexamethasone, indomethacin, isobutylmethylxanthine and rosiglitazone, has potential food safety problems in cultured fat. Therefore, the detection of these residues is necessary to ensure food safety. In this research, a method of high performance liquid chromatography (HPLC) was established to quantitatively analyze the potential residual content of dexamethasone, indomethacin, isobutylmethylxanthine and rosiglitazone in cultured fat and medium. Quantitative analysis showed that the content of four residues in cultured fat decreased to zero on Day 10. Subsequently, enzyme-linked immunosorbent assay (ELISA) was performed to detect the insulin content in the cultured fat and found that the insulin content in the cultured fat on Day 10 was 2.78 ± 0.21 μg/kg. After soaking with phosphate buffered saline (PBS), the insulin content decreased to 1.88 ± 0.54 μg/kg. In conclusion, this research provided an effective approach to clarify the content of potential residual components in cultured fat and it will provide reference for the safety of cultured fat in the future.

Effect of Chinese steamed bun and bread processing on pesticide residues in wheat flour

The changes of five pesticides including imidacloprid, triadimefon, fenitrothion, chlorpyrifos-methyl, and chlorpyrifos in wheat flour during Chinese steamed bun and bread processing were systematically investigated. The pesticide residues were determined by high performance liquid chromatography coupled with diode array detector. Dough mixing step in both Chinese steamed bun and bread processing reduced the concentration of five pesticide residues significantly by 33 to 46%. It was mainly attributed to the increase of moisture content in mixed dough during this step. The reduction of pesticides in fermenting step varied from 2 to 22% in Chinese steamed bun and bread processing. Resting step in both Chinese steamed bun and bread processing has little effect on the pesticide residues with the reduction from 2 to 8%. The five pesticides have different behaviours in steaming step of Chinese steamed bun processing and in baking step of bread processing. During the steaming step, only the concentrations of triadimefon and imidacloprid residues in crust were increased by 52 and 1%, the others in crust and in crumb of Chinese steamed bun were decreased by 4 to 38%. After the baking step, the concentrations of triadimefon and imidacloprid residues in crust, and the triadimefon residue in crumb of bread were increased by 65, 83, and 14%, respectively, the others were all reduced. The processing factors (PFs) for triadimefon and imidacloprid in crust in the steaming and baking steps, for triadimefon in crumb in the baking steps were greater than 1, and the others were all less than 1. Overall, this study provides important references for monitoring pesticide residues in the processing of wheat flour products. The PFs obtained could be helpful for the risk assessment of pesticides in wheat flour products.

Residue levels, household processing evolution and risk assessment of chlorothalonil, SDS-3701, metalaxyl and dimethomorph in Dendrobium officinale Kimura et Migo

Dendrobium officinale, a minor crop with medicinal and edible value, is increasingly entering people's diets, but the pesticide residues on it have received little attention. In this work, field trials were conducted under good agricultural practice (GAP) conditions to investigate the residues of chlorothalonil, SDS-3701, metalaxyl and dimethomorph in D. officinale, then the evolution of these pesticides after household processing were studied. The results indicated that chlorothalonil, SDS-3701, metalaxyl and dimethomorph were 2.41-30.12, 0.20-1.23, 0.07-0.80, 0.19-7.90 mg kg^-1 respectively in stems at recommended preharvest interval (PHI, 30 d). Washing and soaking removed the pesticides in fresh stems with the processing factors (PFs) of 0.41-1.14 and 0.12-1.13, respectively. In brewing test, the transfer rates (TRs) of pesticides in dry stems decreased from the first time (4.27-95.40%) to the third time (3.89-15.57%). Intake risk assessments were also conducted and the risk quotients (RQs) were no more than 27.02% for all compounds in different samples, which indicated acceptable risks for consumers. As effective risk-reducing home processing methods, washing, soaking and multiple brewing were suggested in this work, hoping to help consumers with diet safety.