Determination Of Pesticide Residues Research Articles

Determination of Xinjunan pesticide residue in foodstuffs of plant origin by a modified QuEChERS method and ultra performance liquid chromatography-tandem mass spectrometry

In this study, the determination of Xinjunan pesticide residue in apple, cottonseed, pepper, tomato, grape and pear by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was established. The samples were purified by a modified QuEChERS method. The analysis was performed by UPLC-MS/MS in multiple reaction monitoring (MRM) mode. Acetonitrile and 1.0 mmol L−1 ammonium acetate (containing 0.1% formic acid) were used as the mobile phases. The external standard method was used for quantification. The average recoveries were 75.6–106.2% with an RSD ≤8.8%. The limits of quantification (LOQs) were 2.0 μg/kg for apple, pepper, tomato, grape and pear and 10.0 μg/kg for cottonseed. The proposed method is fast, sensitive, simple, and accurate and could be used for the quantification of Xinjunan pesticide residue in foodstuffs of plant origin.

Determination of pesticide residues by chromatographic methods for food safety

The paper presents a methodology for the preparation of samples of oilseeds, lettuce leaves, apple fruits for the study of xenobiotics by chromatographic control of the following chemical groups of pesticides: benzimidazole derivatives, anilinopyrimidine derivatives, bipyridyl derivatives. The following processes are considered: homogenisation of the sample, purification of the extract by solid-phase or liquid-liquid extraction methods, obtaining of plant extract, and obtaining of analytes extract. For fine-grained homogenised samples of sunflower seeds, the optimal raw material-extractant ratio is 1:20, for paste-like homogenised samples of apple fruit – 1:10, and for liquid samples of homogenised lettuce – 1:5. Analysis of the distribution of xenobiotics parameter in the octane/water system (log Pow), reference data on dielectric constant and dipole moment of solvents allowed identifying extractants capable of dissolving and removing xenobiotics from raw materials. It has been found that a mixture of acetonitrile and methanol (4:1) should be used for the extraction of benzimidazole derivatives and anilinopyrimidine derivatives, bipyridyl derivatives are best extracted with methanolic trifluoroacetic acid (9.5:0.5). The content of xenobiotics in extracts obtained from samples artificially enriched with xenobiotics was quantitatively analysed. Xenobiotics were removed from samples of crop products containing traces of fat. The most difficult process of sample preparation is the process of extracting sunflower seeds. The content of xenobiotics in extracts obtained from samples artificially enriched with analytes is affected by the temperature at which the process takes place and the duration of extraction. Based on the chemical composition of the sample matrix and the list of analytes, the conditions of the variable component of the methodology are proposed: obtaining plant extracts under the action of selective solvents, homogenised raw material-solvent with constant stirring of the extraction system at a speed of 180-200 rpm, or when exposed to ultrasonic vibrations at a frequency of 37 kHz from 4 °C to 25 °C for 5-25 minutes. Control of the qualitative and quantitative composition of the studied plant extracts and extracts of analytes was studied by methods of high-performance liquid and gas chromatography (liquid and gas) with mass-selective detectors

Determination of Pesticide Residues in Strawberry (Fragaria ananassa Duch.) from Upper Punjab Districts of Pakistan

Strawberry (Fragaria ananassa) is grown from mid-October to the end of April in Lahore, Sheikhupura, Sialkot and Gujranwala Districts of the Punjab. A huge amounts of pesticides especially fungicides are sprayed on it indiscriminately to protect it from different diseases and fungal attacks. Present experiment was planned for determination of pesticide residues in strawberry. For this purpose, 40 samples of strawberry were collected from Sheikhupura, Lahore, Sialkot, and Gujranwala districts of Punjab, Pakistan for determination of residues of Malathion, Chlorpyrifos, Profenofos, Atrazine, Carbofuron, Tricyclazole, Difenoconazole, Azoxystrobin, Tebuconazole and Cypermethrin in strawberry. The accuracy, precision, specificity, linearity, limit of detection and quantification were measured. The recovery ranged from 89.3 % to 108% with RSD ranging from 1.66 % to 14.2 %. The linearity showed reliable range (0.995–0.999). The limit of detection ranged from 0.006 to 0.04 μg g-1. Data showed that all the samples contain multi-residues of different pesticides. Among these 40 samples pesticide residues were most often found. All the samples contained multiresidues of different pesticides. The percentage of samples having pesticides residues are , Carbofuron (50 %), Malathion (37.50 %), Profenofos (32.50 %), Chlorpyrifos(25 %), Cypermethrin (20 %), Difenoconazole in (47.50 %), Tricyclazol in ( 52.50 %), Tebuconazole in (50.00 %), and Azoxystrobin in (20 %) of the samples analyzed.

Simultaneous determination of organophosphorus pesticides residues in vegetable, fruit juice, and milk samples with magnetic dispersive micro solid-phase extraction and chromatographic method; recruitment of simplex lattice mixture design for optimization of novel sorbent composites

Dispersive micro solid-phase extraction procedure using a novel and selective sorbent prepared from four components was developed as a sample preparation strategy for extracting five organophosphorus pesticides, including fenitrothion, malathion, ethion, and chlorpyrifos, and diazinon in several vegetables, fruit juices, and cow's milk samples. Due to the high importance of the sorbent in the microextraction process, the percentages of sorbent components, including metal-organic framework (ZIF-67), chitosan, magnetic Fe3O4 nanoparticles, and silica nanoparticles, were optimized by a simplex lattice mixture design. After optimizing the sorbent composite, effective parameters on the extraction of organophosphorus pesticides were optimized using a definitive screening design and Box-Behnken design, respectively. A surfactant (Triton X100) as a dispersion agent with a low volume (10 μL) was utilized in the microextraction procedure to reduce the sorbent dispersion time and increase the sorbent dispersion efficiency. Under the optimal conditions, linearity for the determination of fenitrothion, malathion, ethion, chlorpyrifos, and diazinon was in the concentration ranges of 0.13–1100, 0.27–1000, 0.38–1000, 0.21–1200, and 0.11–1100 ng mL−1 with a determination coefficient higher than 0.9906, respectively. The quantitation limits, detection limits, and relative standard deviations (n = 5) were lower than 0.38 ng mL−1, 0.11 ng mL−1, and 4.59% for the determination of organophosphorus pesticides. The method application for measuring OPPs on cucumber, carrot, tomato, apple juice, orange juice, and cow's milk indicated the presence of residual amounts of malathion in a cucumber sample, diazinon in a carrot sample, and chlorpyrifos in a tomato sample.

A new perspective for electrochemical determination of parathion and chlorantraniliprole pesticides via carbon nanotube-based thiophene-ferrocene appended hybrid nanosensor

The overuse of pesticides for agricultural activities causes adverse effects on human health and can lead to ecological pollution. Therefore, there has been a growing demand for accurate, sensitive, simple, and selective analytical methods for the determination of pesticide residues in food products, soil, etc. In this study, an electrochemical method was developed for the simultaneous determination of parathion and chlorantraniliprole pesticides based on novel electroactive and electropolymerizable group bearing hybrid nanomaterial. The novel hybrid ferrocene-thiophene modified by carbon nanotube (FT@CNT) was prepared by surface modification of the carbon nanotube with thiophene-ferrocene moieties via Click chemistry and used as an electrochemical nanosensor. The experimental conditions such as pH and concentration of the nanosensor were optimized prior to the electrochemical determination of parathion and chlorantraniliprole pesticides in tomatoes, apples and soil samples. The LODs for parathion and chlorantraniliprole in the linear range of 0.02−6.50 μmol/L and 0.01−7.00 μmol/L were determined as 5.3 nmol/L and 8.1 nmol/L, respectively. The accuracy of the electrochemical methods was evaluated by spike/recovery and HPLC analysis in food and soil samples. The comparison between the electrochemical method and other analytical techniques for the determination of pesticides revealed that the electrochemical methods were not only easy to operate and fast but also highly sensitive and selective for the simultaneous determination of parathion and chlorantraniliprole residues in food and soil samples. The hybrid material demonstrated excellent stability and high sensitivity towards parathion and chlorantraniliprole pesticides.

Determination of Acetamiprid by Fluorescence Monitoring of a Glycine-L-Histidine Copper-Organic Framework Aptasensor

The sensitive determination of pesticides constitutes an important aspect in ensuring food safety. Due to the disadvantages of traditional methods, such as low sensitivity, complex operation, and high cost, the development of an efficient and economical biosensor to detect pesticide residues is required. In this work, the dipeptide glycyl-L-histidine (GH) and divalent copper ions (Cu2+) were employed as bioorganic linkers and metal ions in the synthesis of the peptide-based metal organic framework (MOF) material GH-Cu BioMOF. Because of its properties of fluorescence quenching and adsorption of nucleic acids, GH-Cu BioMOF was used to develop a distinctive aptamer based method for the determination of pesticide residues in food. The GH-Cu BioMOF-based aptasensor was used for acetamiprid and demonstrated a linear response in the range from 0.15 to 3.00 µM with a detection limit of 137 nM, verifying the feasibility of this method for pesticide determination in food.

Determination of Pesticides in Apples by High-Performance Liquid Chromatography–Mass Spectrometry (HPLC–MS) with High-Resolution Multiple Reaction Monitoring

High-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (HPLC/QTOF–MS) is reported for quantitative determination of pesticide residues in apples. After a simple, rapid extraction, 300 mg MgSO4, 50 mg primary secondary amine (PSA), and 250 mg octadecyl (C18) were used for sample clean-up to ensure efficient recovery. The pesticides were quantified by HPLC/QTOF–MS using high-resolution multiple reaction monitoring (HR-MRM). Matrix-matched external standard calibration was used for quantitative analysis. The developed method was validated by spiking blank samples with the analytes and provided satisfactory accuracy verified by recoveries from 78.9% to 109.4% and good precision (relative standard deviation ≤12.4%). The limits of quantification for all analytes were between 0.85 and 3.0 µg/kg. The method was successfully applied to the analysis of forty batches of real samples, demonstrating its effectiveness for routine application.

Hierarchical nitrogen-doped holey graphene as sensitive electrochemical sensor for methyl parathion detection

Nitrogen-doped HG featuring a hierarchical macro- and nanoporous 3-D architecture with high pyrrolic-N content is a promising candidate for the construction of sensitive graphene-based electrochemical sensors for environmental and bioanalytical applications. • N-doped HG featuring a hierarchical macro- and nanoporous 3-D architecture for determination of MP was fabricated. • Pyrrolic-N in N-HG played a key role in enhanced electrocatalysis. • First principle calculations indicated that pyrrolic-N exhibited the strongest MP adsorption. • N-HG with a high pyrrolic-N content exhibited excellent sensing performance. • Ultra-low detection and excellent recovery in case of real samples were achieved. The determination of organophosphorus pesticide (OPS) residues is of great importance in reducing environmental pollution and ensuring food safety. A high-performance nitrogen-doped holey graphene (N-HG) electrochemical sensor for determination of methyl parathion (MP; one of the most commonly used OPS) based on a hierarchical macro- and nanoporous 3-D architecture has been successfully developed. The influence of various N-configurations on electron transfer kinetics and the sensing performance of the N-HG modified electrode was investigated systematically through combined practical and theoretical studies. Three N-bonding configurations were investigated in N-HG, namely, pyridinic N, pyrrolic N, and graphitic N. It was found that N-HG with a high pyrrolic-N content exhibited the largest electron transfer rate and the best sensing performance (ultralow detection limits: 3.5 pg·ml −1 ; wide linear range: 1 ng ml −1 –150 μg·ml −1 ), indicating that pyrrolic-N in the N-HG played a critical role in the electrochemical process and in enhanced electrocatalysis, as confirmed by first-principle calculations. Furthermore, the N-HG based sensor exhibited excellent selectivity and freedom from interference, good accuracy and satisfactory recoveries for real samples, confirming N-HG based electrochemical sensors have great scope for applications in environmental analysis and bio-sensing.

Residual Determination of Multiple Pesticides in Vegetable Samples by LC-MS/MS Coupled with Modified QuEChERS-dSPE Ionic Liquid-Based DLLME Method

As a matter of fact, the Dietary Guidelines of the United States of America recommended the consumption of more fruits and vegetables to support the healthy condition of the body. Unfortunately, these food materials are being accumulated with pesticidal residues due to the continuous miss-management and excessive application of the chemicals during pre and post-agricultural practices, which compels multiple analysis of pesticidal residues to know their concentration levels for the betterment of food security and safety. For that matter, multi-residues of Thiamethoxam, Propamocarb, Carbaryl, Metalaxyl, Baycarb, Thiobencarb, Diazinon, and Dursban pesticides were determined in the samples of lettuce, garlic, ginger, and bell-pepper using modified QuEChERS-dSPE Ionic Liquid-based dispersive liquid-liquid microextraction (DLLME) method coupled with LC-MS/MS instrument and validated (European Union Guideline). Resultantly, the accuracy (87-127%) and precision (0–22%) were mostly within the acceptable range for the former (70-120%) and latter (≤20%). Meanwhile, the limit of detections (0.01-0.28 µg/kg) and limit of quantitations (0.03-0.93 µg/kg) were satisfactory. The concentration range (5–400 µg/kg) of calibration curves for the evaluated linearity were linear with coefficient of regressions greater than 0.99. The matrix effects for all the analyzed samples were very weak and less effective (≤ -86%). The range (1–25%) for the estimated measurement uncertainties were certifiable and acceptable (≤ 50%). Therefore, the sample preparation method prove effective as validated and useful for the multiple determination of pesticides residues in the analyzed vegetable samples, which are presumably safe for consumption against health issues.

Optimization and evaluation of four multi-residue methods for the determination of pesticide residues in orange oil using LC-MS/MS and GC-MS/MS: a comparative study

ABSTRACT Orange oil is considered the largest produced essential oils worldwide due to its unique properties. Pesticide residues in orange oil are expected to be much higher than the original fruit due to orange peel’s cold-pressing during orange oil production. These residuesmaycause various health problems if consumed. The purpose of our study was to optimize and compare four multi-residues extraction methods (dilution, QuEChERS, ethyl acetate, and mini-Luke) for analysis of 387 pesticides in orange oil using LC-MS/MS and GC-MS/MS. To our knowledge, this is the first report on the use of ethyl acetate and the mini-Luke method for the analysis of orange oil. The comparison was based on recoveries, matrix effect, and the amount of co-extract matrix. The optimum mean recoveries were obtained by the ethyl acetate method, which successfully analyzes 371 out of 387 pesticides with acceptable recovery (70–120%). It also showed a narrow recovery distribution in the range of 90–110% for 69% of all studied pesticides. Regarding the matrix effect, the QuEChERS method gave the highest number of pesticides with an in significant matrix effect (80–120%) for both LC and GC amenable pesticides. The least amount of co-extract matrix components according to GC-MS/MS scan and gravimetric analysis has been achieved by the QuEChERS method. In conclusion, the Ethyl acetate method gives acceptable recovery for a wide range of pesticides with a narrow recovery distribution and a moderate amount of co-extract matrix. While the QuEChERS method provides better selectivity and cleaner extract but with a narrow scope and less precision.

SALLE combined with LD-DLLME for pesticides analysis in sugar and soil samples

In this study, a modified salting-out-assisted liquid-liquid extraction (SALLE) combined with low density dispersive liquid-liquid microextraction (LD-DLLME) has been developed for quantitative determination of multiclass pesticide residues (atrazine, diazinon, ametryn, terbutryn, chlorpyrifos, dimethametryn, 4,4'-dichlorodiphenyldichloroethylene (4,4'-DDE), 4,4'-dichlorodiphenyldichloroethane (4,4'-DDD) and 4,4'-dichloro- diphenyltrichloroethane (4,4'-DDT)) levels in sugar and soil samples coupled with gas chromatography–mass spectrometry (GC-MS) detection. The extract was enriched after combining SALLE to LD-DLLME and enrichment factor obtained ranged 30-121. Under the optimum conditions, the linearity of the method was in the range of 6.25–100 ng g-1 for atrazine, ametryn, terbutryn, dimethametryn and 4,4'-DDT, and in the range of 2.5–100 ng g-1 for diazinon, chlorpyrifos and 4,4'-DDD, and in the range of 1–100 for 4,4'-DDE with correlation coefficient of 0.992 or better. The limits of detection (LODs) ranged from 0.01–0.25 ng g-1. The precisions as %RSD, were below 10% for both matrices. The recoveries obtained from spiked sugar and soil samples at 5 and 50 ng g-1 ranged from 79 to 111%. The method was subsequently applied to real sugar and soil samples. All the pesticides investigated were not detected in the sugar sample. The soil sample was contaminated by atrazine and ametryn at concentration level of 0.3 and 0.2 ng g-1, respectively.
 
 KEY WORDS: SALLE, LD-DLLME, Extraction, Pesticide residues, Sugar, Soil
 
 Bull. Chem. Soc. Ethiop. 2021, 35(1), 1-16.
 DOI: https://dx.doi.org/10.4314/bcse.v35i1.1

Screening for pesticide residues in soil and crop samples in Egypt

Pesticide application is an important issue in intensive agricultural production to achieve self-sufficiency in food production. This study aimed to the determination of pesticide residues from soil samples cultivated with different crops. Forty soil samples from four governorates, ten samples each (Kafr El-Sheikh, El-Beheira, Giza, and Menoufia) were collected for pesticides multi-residual analysis. Also, fifteen vegetable samples were collected from Giza governorate and analyzed for the presence of pesticide residues. Obtained data revealed that soil samples of Giza governorate recorded the highest level of pesticide residues contamination with 70% positive samples followed by Kafr El-Sheikh and Menoufia governorates with 60% positive samples and finally El-Beheira governorate recorded the lowest level of pesticide residues contamination with 30% positive samples. Regarding the levels of pesticide residues in vegetables and crops, about 53.3 % of tested samples (onion, sweet potato, molokhia, cabbage, beet, okra, eggplant, and lettuce) were free from pesticide residues. Meanwhile, about 46.7 % of tested samples (wheat, rocca, green dill, tomato, radish, pepper, and green parsley) showed pesticide residues with different types and concentrations. Propiconazole was the highest residue recorded in green dill with 3.8 mg/kg followed by difenoconazole with 3.22 mg/Kg present in green parsley.

Qualitative Determination of Pesticide Residues in Purple Cabbage Based on Near Infrared Spectroscopy

A qualitative detection model of pesticide residues based on near infrared spectroscopy and support vector machine (SVM) classification is proposed in this paper. The model was used to identify the pesticide free purple cabbage and pesticide containing purple cabbage. Cypermethrin, matrine and avermectin were selected respectively, and the ratio of pesticide and water was 1:100. The correct rates of classification and identification were 90%, 100% and 100%, respectively. The experimental results show that the model has high accuracy and universality for qualitative analysis of pesticide residues in purple cabbage. This paper presents an effective method for rapid and nondestructive detection of pesticide residues in vegetables.

Simultaneous determination of multiple pesticide residues in Iranian saffron: A probabilistic health risk assessment

Saffron is a strategic agricultural product having extensive flavoring applications in Asia. Although utilization of pesticides for its cultivation is limited, there is a possible risk of contamination in this prominent spice. Herein, 88 pesticides were analyzed in 34 fsamples collected from the most crucial saffron-rich region of the country using a miniaturized QuEChERS approach and ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Results indicated that LOQs and LDR were within the ranges of 5–50 and 5−1000 μg L−1 (5.49–54.9 and 5.49−1099 μg Kg−1), respectively. Considering LOQ values, 3.4 % out of 34 samples were contaminated by at least one pesticide. The highest mean values related to carbendazim and iprodione were obtained to be 10.6 and 8.79 μg Kg−1, respectively. However, only eight samples exhibited pesticide residues higher than the limits specified by European Union. Furthermore, probabilistic human health risk assessment of pesticides was investigated using a Hazard Quotient (HQ) method in Monte Carlo (MC) algorithm. Total Hazard Quotient (THQ) values according to the consumption of saffron in adults and children were calculated as 2.5E-5 and 1.2E-4, respectively. Consequently, the applied health risk assessment on Iranian saffron samples revealed that HQ for adults and children populations might not pose health hazards. Most Iranian saffron samples are safe; their pesticide residue levels are below the EU MRLs, and the observed mean values were much lower than MRLs.

HPLC-DAD METHOD FOR DETECTION OF SOME PESTICIDE RESIDUES IN SOIL AND CROPS CULTIVATED IN BANAT COUNTY

High productivities and economic benefits in modern agriculture have been accomplished only by the use of pesticides. The introduction of these compounds in the food chain can be considered a risk for human health due to their toxicity. So, pesticides residues and their degradation products resulted by hydrolytic, photochemical and microbial processes in soil and cereals must be monitored and controlled. The aim of this research was to develop rapid and sensitive HPLC-DAD methods for residues detection of several pesticides, imidacloprid, amidosulfuron, bromoxynil and deltamethrin, from soil and some crops, maize, wheat and rape seeds, cultivated in Banat County-Moravita Zone. In order to perform the pesticides extraction, the samples were subjected to an ultrasonic technique, at 59 kHz and 30°C, during 30-45 min., using acetonitrile and acetonitrile-water mixture as solvents. Acetonitrile alone proved to be more appropriate for this purpose. The HPLC analyses were conducted on HPLC-DAD apparatus, Dionex Ultimate 3000 (Dionex Corp., USA), equipped with quaternary pump LPG 3400A, thermostat of columns TCC-3000 and a C-18 Acclaim® 120 Silica-reversed-phase (4.6x150 mm, 5 µm) column, using different compositions of acetonitrile-water as mobile phase. The presented HPLC - Dionex system proved to be very suitable for determination of pesticides residues in soil and crops.

Validation of a high-throughput method for analysis of pesticide residues in hemp and hemp products

Hemp has been an agricultural commodity for millennia, and it has been undergoing a resurgence in interest and production due to its high content of cannabinoids, protein, fiber and other ingredients. For legal possession and use throughout the USA, hemp and hemp products must have delta-9-tetrahydrocannabinol (THC) concentration < 0.3%. As with most crops, pesticides may be applied when farming hemp, which need to be monitored in food, feed, and medicinal products. The aim of this work was to evaluate and validate the recently developed “quick, easy, cheap, effective, rugged, safe, efficient, and robust” (QuEChERSER) sample preparation mega-method to determine pesticide residues in hemp plants, flowers, powders, oils, and pellets. High-throughput analysis of final extracts for 106 targeted pesticides and metabolites from North American monitoring lists entailed: 1) ultrahigh-performance liquid chromatography - tandem mass spectrometry (UHPLC-MS/MS) with column back-flushing, and 2) instrument-top sample preparation + low-pressure gas chromatography (ITSP+LPGC-MS/MS). In QuEChERSER, 2 g sample is extracted with 10 mL 4/1 (v/v) acetonitrile/water by mechanical shaking for 10 min, followed by 3 min centrifugation. For LC, 0.2 mL of extract is taken and solvent exchanged into initial mobile phase followed by 5 min ultra-centrifugation prior to the 10 min analysis. For GC-amenable pesticides, the remaining initial extract is partitioned with 4/1 (w/w) anh. MgSO4/NaCl, and 1 mL is taken for automated ITSP cleanup in parallel with 10 min LPGC analysis. In the former case, the UHPLC column is back-flushed with 1/1 (v/v) methanol/acetonitrile for 3 min between each injection to keep the system clean and avoid ghost peaks. Multi-level, multi-day validation results achieved 70–120% recoveries with RSDs < 20% for more than 80% of the analytes in hemp protein powder, oil, pellets, and fresh plant (dried hemp plant and flower were too complex). Limits of quantification (LOQs) were < 10 ng/g were achieved for nearly all pesticides, yielding 2.8% false negatives among >13,000 analyte results in the spiked samples. The QuEChERSER method was demonstrated to meet the challenge for several complex hemp matrices.

Microextraction by packed sorbent of selected pesticides in coffee samples employing ionic liquids supported on graphene nanosheets as extraction phase.

This paper describes the synthesis, characterization, and use of ionic liquids supported on silica, functionalized with graphene oxide through covalent bonding (ILz/Si@GO), as sorbents for microextraction by packed sorbent (MEPS). Seven selected pesticides (diazinon, heptachlor, aldrin, endrin, dieldrin, endosulfan, and methoxychlor), used for the prevention of pests in coffee crops, and endosulfan sulfate-an endosulfan metabolite-were selected for this study as model compounds for evaluating the sorbent performance of the synthesized materials in the MEPS device. The cycles of each of the stages were previously optimized through univariate experiments to carry out the extraction. The ILz/Si@GO phase was compared to other sorbents used in MEPS (GO, DVB-MMA, C4/SiO2, C8/SiO2, ILz/SiO2, and bare silica) and also with graphene functionalized through other methodologies, where ILz/Si@GO showed the best results. The material was characterized using a range of techniques. The selectivity of the sorbent material and its adsorption capacity were evaluated by gas chromatography coupled with tandem mass spectrometry. The precision and accuracy of the method showed a relative standard deviation lower than 10% and recoveries from 35 to 97%. Finally, the proposed method was employed for the determination of pesticide residues in coffee samples.

Microbiological quality and determination of pesticide residues in the lettuce produced in Bahía Blanca's horticultural belt, Argentina

The aims of this research were 1) to find out the possible microbiological contamination and residues of pesticides (chlorpyrifos and cypermethrin) in lettuce grown in Bahía Blanca’s horticultural belt, and bacteriological quality of waters used for irrigation and post-harvest washing, 2) to investigate and compare the internalization capacity of a strain of Escherichia coli isolated from irrigation water with another hospital uropathogenic strain. Some strains of bacteria can internalize into the plant tissue. This capability presents food safety threats as they cannot be removed with standard sanitation practices. To determine bacteriological quality of lettuce, E. coli, Salmonella spp and E. coli O157: H7/NM (n = 10) were investigated. Bacteriological quality of water was determined by quantification of fecal coliforms/100 mL (n = 20). Pesticides were determined by using an improved and validated QuEChERS method combined with GC-MSD. Irrigation water in 19/20 samples did not present health risk. Bacteriological quality of lettuce met demands in 9/10 samples. Pesticides were detected in half of the samples, values exceeding the FAO recommendations. An effort is strongly recommended to implement both, best phytosanitary practices and monitoring programmes. Uropathogenic strain was able to internalize into plant tissue, while the nonpathogenic one was not.

Development of a new generic extraction method for the analysis of pesticides, mycotoxins, and polycyclic aromatic hydrocarbons in representative animal feed and food samples

Various generic extraction methods have been used to determine pesticide residues, mycotoxins, and polycyclic aromatic hydrocarbons (PAHs) in food and animal feed to ensure consumer safety. However, these methods cannot extract all relevant compounds at an acceptable rate of recovery. This study presents a new extraction method. This new method facilitated the identification of 231 compounds, including 196 pesticides, 11 mycotoxins, and 24 PAHs over a broad range of polarities. These compounds were identified in various sample matrices, including those that are lipid-rich. The processed sample is first extracted with water, acetonitrile, formic acid, and heptane. The addition of ammonium formate results in separation into three phases and enables analysis of the aqueous phase. Solid-phase extraction clean-up procedures were performed as necessary followed by analysis by liquid or gas chromatography and mass spectrometry. Analyte recoveries were typically in the range of 70 – 120% with relative standard deviations below 20%.

Determination of Pesticide Residues in Food Premises Using QuECHERS Method in Bench-Sheko Zone, Southwest Ethiopia

Pesticides are risk factors in human life causing chronic human health effects. They are commonly used across the globe to enhance human endeavors. In Ethiopia, pesticides are widely used by local farmers and governmental organizations for pest control purpose. Pesticide residues in food items have been a concern to the consumers and environment they live in. Therefore, this study was aimed at determining the amount of organochlorine and organophosphate pesticide residues in cereal crops in Bench-Sheko Zone, Ethiopia. A cross-sectional laboratory-based study design was employed to determine the amount of pesticide residues. The samples were extracted using a Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) extraction and clean up method. Finally, the extracted samples were injected into gas chromatography tandem mass spectrometer and the types and concentrations of pesticide residues were analyzed. The highest concentration of endosulfan sulfate (0.076 mgkg−1) was detected in rice, followed by dimethoate (0.068 mgkg−1) and p,p′-DDE (0.087 mgkg−1) in sorghum and common millet, respectively, in the samples obtained from the Gurafarda site.The highest concentration of p,p′-DDT (0.133 mgkg−1) was detected in common millet, followed by aldrin (0.082 mgkg−1) and dimethoate (0.077 mgkg−1) in sorghum and common millet, respectively, in the samples obtained from the North Bench site. In addition, aldrin detected in rice, sorghum, and common millet obtained from the three sites was a residue of above the maximum residual limits set by Codex Alimentarius regulations and European Union. The finding shows that an indication of the widespread use of pesticides in cereal crops.