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1.
A sensitive and rapid analytical method based on QuEChERS (quick, easy, cheap, effective, rugged and safe) sample preparation and LC-MS/MS detection was developed for the analysis of halosulfuron-methyl residues in wheat. The recoveries of halosulfuron-methyl in both the wheat plant and grain ranged from 87% to 119% and from 75% to 97%, respectively, with relative standard deviations (RSDs) of 3–9%. The limit of quantification (LOQ) was 0.005 mg kg?1 for wheat plant and 0.001 mg kg?1 for wheat grain. The half-life of halosulfuron-methyl in the wheat plant was 0.9–9.5 days. The terminal residue levels of halosulfuron-methyl in wheat grain were below 0.01 mg kg?1 at harvest.  相似文献   

2.
Persistence of fluopicolide and propamocarb in tomato was studied following three applications of a combination formulation of Infinito 68.75 SC (fluopicolide 6.25 %?+?propamocarb 62.5 %) at 1500 and 3000 mL ha?1 by 7 days interval, starting the spray at fruit development stage. QuEChERS method included extraction of sample with ethyl acetate and cleanup of dispersive solid-phase extraction was used for the determination of fluopicolide and propamocarb residues on tomato and soil. Residues of fluopicolide and propamocarb in tomato were estimated by gas–liquid chromatography and gas chromatograph–mass spectrometry, respectively. Half-lives for fluopicolide were found to be 2.58 and 2.31 days, whereas for propamocarb these values were observed to be 1.49 and 2.08 days at single and double the application rates, respectively. Residues of fluopicolide dissipated below its limit of quantification (LOQ) of 0.01 mg kg?1 after 7 and 10 days at single and double the application dosage, respectively. Similarly, residues of propamocarb took 5 and 7 days to reach LOQ of 0.10 mg kg?1, at single and double dosages, respectively. Soil samples collected after 15 days of the last application did not show the presence of fluopicolide and propamocarb at their detection limit of 0.01 and 0.10 mg kg?1, respectively. The initial deposit of residues of propamocarb and fluopicolide for both the dosages were below the prescribed codex maximum residue limit values of 2 and 1 mg kg?1, respectively. Therefore, a 1-day waiting period was suggested to reduce human health risks before consumption of tomato fruits.  相似文献   

3.
To date there have been no reports of methods to determine Tinopal CBS-X. We developed a rapid and simple method to determine the Tinopal CBS-X content in rice noodles and rice papers using HPLC equipped with fluorescence detection. Heating the rice noodles and rice papers to 80°C after adding 75% methanol solution induced the release of Tinopal CBS-X from processed rice products. Tinopal CBS-X was separated using an isocratic mobile phase comprising 50% acetonitrile/water containing 0.4% tetrabutyl ammonium hydrogen sulphate at pH 8.0. The samples suspected to be positive by HPLC analysis were then confirmed by LC-MS/MS analysis. This study also investigated the Tinopal CBS-X content of three rice noodle products and two rice papers. The limits of quantification for rice papers and rice noodles were 1.58 and 1.51 µg kg–1, respectively, and their correlation curves showed good linearity with r2 ≥ 0.9997 and ≥ 0.9998, respectively. Moreover, rice papers had recoveries of 70.3–83.3% with precision ranging from 5.0% to 7.9%, whereas rice noodles had slightly lower recoveries of 63.4–78.7% and precisions of 8.5–11.5%. Only one rice noodle product contained Tinopal CBS-X, at around 2.1 mg kg–1, whereas it was not detected in four other samples. Consequently, Tinopal CBS-X from rice noodles and rice papers can be successfully detected using the developed pre-treatment and ion-pairing HPLC system coupled with fluorescence detection.  相似文献   

4.
Total mercury (THg) levels in 440 pairs of milled rice samples and brown rice samples from 15 major rice grain-producing provinces of China were measured and the associated health risk via rice consumption for different age categories of Chinese population was also assessed. THg contents were measured by a direct mercury analyser and the limit of detection (LOD) was 1.5 μg kg?1. The THg levels for milled rice samples and brown rice samples varied from non-detected to 17.8 μg kg?1 and 1.5 to 25.4 μg kg?1, respectively, with a mean level of 3.4 μg kg?1 and 4.9 μg kg?1, respectively. The THg levels in all milled and brown rice samples were generally low, except three brown rice samples having concentrations above the legally set value for cereals (20 μg kg?1 Hg). THg intakes for different age categories were estimated according to THg content and corresponding rice consumption and the associated health risk was evaluated by the corresponding provisional tolerable weekly intake (PTWI) for THg (5.0 μg kg?1 bw week?1), which was established by the Joint FAO/WHO Expert Committee on Food Additives (JECFA). The 50th percentile of the THg intakes via milled rice and brown rice consumption for different age categories was in the range 0.09–0.19 μg kg?1 bw week?1 and 0.14–0.27 μg kg?1 bw week?1, respectively, well below the PTWI, suggesting that the associated health risk is relatively low. However, the 99.9th percentile of the THg intakes for 2–4-year-old children amounted up to 20.6% of the PTWI (milled rice) and 29.5% of the PTWI (brown rice), which deserves attention.  相似文献   

5.
This paper reports the evaluation of the Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) method for the determination of polycyclic aromatic hydrocarbons (PAHs) in food of animal origin with GC–MS detection. Although in the available literature, there is a lot of information about sample preparation method for PAHs determination in food samples, but the QuEChERS method application for PAHs determination in food of animal origin has not been reported as yet. The results showed that the best recovery ratios 72.4–110.8 % with relative standard deviation lower than 10 % for all determined compounds were received for the method with ethyl acetate as an extraction solvent, primary–secondary amine and C18 sorbents and evaporation to dryness and dissolving the residues in the hexane. The limit of quantification ranged from 0.0003 to 0.0030 mg kg?1 for pyrene and benzo[a]anthracene, respectively. This method was also used for the determination of PAHs in 15 samples of pork ham. In 8 of 15 samples selected, PAHs were identified. It was observed that in 6 cooked ham and one smoked and cooked samples, any PAHs were found. In other samples, which were smoked and roasted, some low concentration of PAHs was detected. In one sample benzo[a]pyrene (0.0015 mg kg?1), in one sample benzo[b]fluoranthene (0.0015 mg kg?1) and in one sample chrysene (0.0024 mg kg?1) were detected. A number of other less harmful PAHs were also determined. There were no exceedances of maximum levels (according to Commission Regulation (EU) No 835/2011) for determined PAHs in any of the analysed samples.  相似文献   

6.
A simple analytical method combining solvent extraction and liquid chromatography-high-resolution mass spectrometry (LC-HRMS) was developed for the analysis of pesticide residues in rice bran protein powder. Owning to the high accuracy of HRMS in determination of mass to charge ratio (m/z), a suspect screen of pesticide residues was performed by LC-HRMS prior to quantification analysis. Based on the theoretical m/z, four pesticides including isoprothiolane (IPT), tebuconazole (TBZ), propiconazole (PCZ), and tricyclazole (TCZ) were detected and further verified with their reference standards. The solvent extraction conditions were optimized according to the signal intensity of extracted ion chromatogram (XIC) in LC-HRMS. After optimization, 50% acetonitrile solution was adopted, in which the targeted pesticides could be extracted effectively (recoveries/accuracy of >?85%) with the good reproducibility (relative standard deviation (RSD)?<?10.3%). Two isotope internal standards isoprothiolane-D4 (IPT-D4) and propiconazole-D5 (PCZ-D5) were applied in quantification, and the quantification results were highly consistent with those from the standard addition method. Limit of detections (LODs) and limit of quantifications (LOQs) of the method were about 0.05–0.2 and 0.2 to 1 μg kg?1, respectively, without additional purification/enrichment for these analytical targets. The developed method was applied for the analysis of five different batches of rice bran protein samples. It was found that these four pesticide residues were all below 0.02 mg kg?1, well less than the maximum residue levels (MRLs) in the latest regulations in EU and China (0.1–5 mg kg?1). Besides the rice bran protein powder, this suspect screen followed with targeted quantification approach by LC-HRMS could also be applied for other rice derivative products analysis.  相似文献   

7.
Being susceptible to any matrix with pH >5, taking cabbage as an example, the low recovery of chlorothalonil residues adsorbed onto the cabbage matrix was almost completely improved by extracting with 1/1 (v/v) acetonitrile (containing 5 % acetic acid)/toluene. Under the optimized conditions, the recoveries of chlorothalonil in cabbage fortified at three concentrations of 0.5 to 10 mg kg?1 were 71–93 % with relative standard deviations (RSDs) lower than 6 %. The limit of detection (LOD) and the limit of quantification (LOQ) of the gas chromatography–mass spectrometry (GC–MS) method for chlorothalonil were 0.05 and 0.5 mg kg?1, respectively, which were much lower than the maximum residue limits (MRLs). The proposed analytical method demonstrated a potential for its application to monitor for chlorothalonil and to help assure food safety, especially base-sensitive-pesticide analysis.  相似文献   

8.
A sample pretreatment method was established to analyze the residues of cyenopyrafen in citrus peel, pulp, and whole fruit using ultra-performance liquid chromatography coupled with tandem mass spectrometry. The target compound was extracted from all matrices with acetonitrile and then cleaned by dispersive solid phase extraction using 10 mg GCB?+?150 mg MgSO4 for citrus peel; 50 mg PSA?+?150 mg MgSO4 for citrus pulp, and 50 mg C18?+?50 mg PSA?+?150 mg MgSO4 for whole fruits. Determination of the target compound was achieved in less than 5.0 min using an electrospray ionization source in positive mode. Average recoveries in citrus peel, pulp, and whole fruit spiked at 0.01, 0.2, and 2 mg kg?1 ranged from 84.9 to 105.1%, with relative standard deviations (RSDr) of 0.7–7.9%. The reproducibility (RSDR) ranged from 2.6 to 6.8%. The limits of detection and quantification ranged from 0.00032 to 0.0012 mg kg?1 and from 0.0009 to 0.0036 mg kg?1, respectively. This method was used to determine cyenopyrafen residues in citrus fruits to study its dissipation under field conditions. The trial results showed that the half-lives of cyenopyrafen in whole fruits were 10.2 and 6.2 days in Hunan and Guangxi provinces, respectively. The developed analytical method provides a basis to establish maximum residue limits and monitor cyenopyrafen residue in citrus.  相似文献   

9.
An effective analytical method for the residue analysis of a novel insecticide chlorantraniliprole and its dissipation in grape were studied. Chlorantraniliprole residues were extracted from grape samples with ethyl acetate. The extract was cleaned up with QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method and determined by high-performance liquid chromatography with photodiode array detector (HPLC-DAD). At fortification levels of 0.06, 0.5, and 1.0 mg kg?1 in grape, it was shown that recoveries ranged from 95.11 to 102 % with relative standard deviation (RSD) of 6 to 11 %. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 0.02 and 0.06 mg kg?1, respectively. The dissipation half-life time of chlorantraniliprole residues in grape was 2.70 days. According to maximum residue limit (MRL), the preharvest interval (PHI) of chlorantraniliprole on grape was 4 days after the treatment. Based on the results of this study and the relevant residue regulation, chlorantraniliprole residue levels will be acceptable when applied to grape in Egypt.  相似文献   

10.
Eggs were used to study the determination and depletion of amoxicillin (AMO) residues after oral dosing hens (25.0 mg kg–1, 50.0 mg kg–1 body weight), once daily for five days. A reverse-phase high-performance liquid chromatography with fluorescence detection (RP-HPLC-FLD) method was developed to determine AMO residues in albumen, yolk and whole egg. By using pre-column derivatisation, an improved liquid–liquid extraction procedure was developed for sample preparation. AMO were extracted from eggs with acetonitrile. The extract solution was extracted using saturated methylene chloride. The supernatant was reacted with salicylaldehyde under acidic and heating conditions. Limits of detection (LODs) were 1.2 ng g–1 and limits of quantification (LOQs) were 3.9 ng g–1 for AMO. Recoveries of AMO from samples fortified at levels of 5.0–125.0 ng g–1 ranged from 79.1% to 88.5% in albumen, 78.6–83.6% in yolk and 78.3–85.1% in whole egg, with coefficients of variation of ≤7.3%. The maximum concentrations of AMO in albumen, yolk and whole egg were found to occur at 1.5, 2.5, 1.5 days after withdrawal of medication respectively. AMO was not detectable in albumen at 7.5 days after final administration of AMO, at 10.5–11.5 days in yolk and 10.5 days in whole egg after administration of two oral doses. The method was applied during the residue study of AMO in order to formulate a reasonable withdrawal period to ensure food safety.  相似文献   

11.
A simple and sensitive LC-MS/MS method was developed and validated for the determination of ampicillin (ABPC) in chicken eggs. Residues were extracted by reverse-phase solid-phase extraction. Chromatographic separation was performed using a reverse-phase column with an elution gradient. The limits of detection and quantification were 0.01 and 0.1 ng g?1, respectively. For the 0.1–50 ng g?1 concentration range, mean recovery and accuracy values were 93.9–98.5% and 100.2–118.0%, respectively. ABPC residue concentrations in eggs before, during and after 7 days of medicated feeding of maximum dosage (40 mg kg?1 body weight day?1) of ABPC were determined with the LC-MS/MS method. The maximum concentration of ABPC in eggs was 3.6 ± 1.7 ng g?1 (mean ± SD) on the last day of the administration period. Residue concentrations of ABPC in eggs during and after ABPC administration were not over the Japanese maximum residue limit of 0.01 mg kg?1.  相似文献   

12.
In this study, an ultra-high-performance liquid chromatography method was developed to detection the levels of 5-hydroxymethyl-2-furfural (HMF) in 227 selected food products obtained from the Chinese markets. The performance of the analysis method was evaluated by some quality parameters such as limit of detection (LOD), limit of quantification (LOQ), linearity, recovery, and run-to-run (n?=?6) and day-to-day (n?=?18) precisions. The LOD and the LOQ of the method in different food matrices ranged from 0.15 to 0.50 and from 0.35 to 1.20 mg kg?1, respectively. The results from this study showed that HMF was mostly detected in all samples selected. HMF contents in different samples varied greatly according to the raw materials and processing conditions. The highest level of HMF was found in preserved fruits and ground coffee, with average levels of 409.6 and 409.9 mg kg?1, respectively. Preliminary estimates of HMF exposure from foods in the Chinese population was estimated to be 0.12 mg kg?1 body weight day?1, which is relatively low compared with the result reported by JECFA and European Food Safety Authority.  相似文献   

13.
During 2012–2014, 170 samples of export quality raisins were collected from different vendors in Pakistan. The collected samples were analysed for the presence of aflatoxins (AFs) and Ochratoxin A (OTA) contamination using high-performance liquid chromatography technique. The limit of detection and limit of quantification of AFs/OTA were 0.12/0.10 and 0.36/0.30 µg kg?1, respectively. Only 5% of the samples were contaminated with AFs, ranging 0.15–2.58 µg kg?1 with a mean of 0.05 ± 0.26 µg kg?1. None of the raisin samples exhibited AFs contamination above the maximum limit (ML = 4 µg kg?1) as set by the European Union (EU). About 72% of the samples were contaminated with OTA, ranging 0.14–12.75 µg kg?1 with a mean of 2.10 ± 1.9 µg kg?1. However, in 95.3% of the tested samples, OTA level was lower than the ML of 10 µg kg?1 as regulated by the EU. Apparently, a strict and continuous monitoring plan, including regulatory limits, improves food safety and quality for all types of commodities.  相似文献   

14.
A rapid, simple and effective method for the determination of citrinin in rice by UHPLC coupled to fluorescence detection has been developed and validated. Extraction of citrinin from rice samples was achieved by applying a QuEChERS-based extraction/partitioning process with water and acetonitrile, without the need of further extract clean-up. The method was fully validated for white rice, and its applicability in other rice matrices, such as brown and red rice, was confirmed by recovery experiments. Under optimum conditions, recoveries ranged from 72.5% to 92.8%, with relative standard deviations (RSDs) lower than 7.1%. Detection and quantification limits were estimated to be 1.5 and 5.0 µg kg?1, respectively. Finally, 21 organic rice samples were analysed, but none was contaminated with citrinin above the detection limit of the method. The method proved to be fast and non-laborious.  相似文献   

15.
An improved method for the analysis of propylene glycol (PG) in foods using a gas chromatography-flame ionisation detector (GC-FID), with confirmation by GC-MS, was validated by measuring several analytical parameters. The PG concentrations in 1073 products available in Korean markets were determined. PG was detected in 74.1% of the samples, in a concentration range from the limit of detection (n.d., 0.39 μg ml?1) to 12,819.9 mg kg?1. The Korea National Health and Nutrition Examination Survey (KNHANES) 2011–2013 reported the mean intake levels of PG from all sources by the general population and consumers were 26.3 mg day?1 (0.52 mg kg?1 day?1) and 34.3 mg day?1 (0.67 mg kg?1 day?1), respectively. The 95th percentile intake levels of the general population and consumers were 123.6 mg day?1 (2.39 mg kg?1 day?1) and 146.3 mg day?1 (2.86 mg kg?1 day?1), respectively. In all groups of the general population, breads were the main contributors to the total PG intake. These reports provide a current perspective on the daily intake of PG in the Korean population.  相似文献   

16.
A method using QuEChERS sample preparation with liquid chromatography polarity-switching tandem mass spectrometry was developed and validated for the analysis of quinclorac and its degradation product quinclorac methyl ester in canola seed. The method was used to analyse canola treated with quinclorac, harvest sample composites and samples of canola shipments. Quinclorac residues were present in all samples of canola treated with a quinclorac-containing herbicide that were analysed. Quinclorac was found in 93% of samples, with an average of 0.018 mg kg–1. All samples contained quinclorac methyl ester, with an average of 0.061 mg kg–1. The average concentration of total residues (as quinclorac equivalents) on treated canola was 0.075 mg kg–1, with a range of 0.016–0.124 mg kg–1. The observed residues were all at least 10 times lower than the Canadian maximum residue limit of 1.5 mg kg–1. Quinclorac and quinclorac methyl ester were not found in any harvest and export composite samples, which represented the majority of canola grown in western Canada in 2015 and canola exported in late 2015. Even though usage of quinclorac-containing herbicide on canola can result in the presence of low concentrations of residues, the absence of quinclorac residues in harvest and shipment samples suggests that use of quinclorac-containing herbicide was not widespread, and that any residues present were diluted as canola was combined along the grain-handling chain into shipment lots, or segregated and prevented from entering shipment lots.  相似文献   

17.
A method was developed for the determination of glyphosate residues in plant-derived food using a two-step solid phase extraction (SPE) combined with mixed-mode liquid chromatography-tandem mass spectrometry (LC-MS/MS). The samples were extracted with water. Then, the extracting solution was pretreated by a C18 cartridge to remove protein and weak-polar interferences and further directly extracted using a strong anion exchange (SAX) cartridge to remove neutral and basic substances. The obtained glyphosate residues from the SPE were separated on a hydrophilic interaction/weak anion-exchange (HILIC/WAX) column and detected by mass spectrometry with negative electrospray ionization (ESI-) in multiple reaction monitoring (MRM) mode. This approach was evaluated by five different kinds of plant-derived food (soybean, corn, carrot, apple, and spicy cabbage) matrices in terms of matrix effect and recovery. Results showed that two-step SPE and mixed-mode chromatography separation provided the method with a very low matrix effect, and the spiked recoveries of glyphosate were satisfied in the range of 83.1 to 100.8 % at three spiked levels. The limit of quantification (LOQ) and detection (LOD) of the method in different matrices were 0.016–0.026 and 0.005–0.008 mg kg?1, respectively. The procedure was validated and showed good accuracy and precision over a large linear range of 0.02–10 mg kg?1.  相似文献   

18.
A pressurized liquid extraction (PLE) method was developed for melamine analysis in pet foods. The PLE method which utilized an accelerated solvent extraction (ASE®) system was also compared with sonication and polytron extraction methods. The parameters for the optimized PLE method were temperature (75?°C for wet pet food, 125?°C for dry pet food), pressure (1,500 psi), static time (10 min), flush volume (40%), purge time (1 min), and number of cycles (1). Recoveries obtained by PLE method were significantly higher (P?≤?0.05) than those of sonication and polytron methods for dry pet food samples. For the analysis of adulterated pet foods, PLE resulted in the highest melamine content followed by sonication and polytron. Using PLE, samples fortified with melamine at 2.5 and 100 mg kg?1 resulted in recoveries ranging from 55% to 90% for wet samples and from 90% to 116% for dry samples. Low recovery rate from wet samples at low spike level (2.5 mg kg?1) may have been caused by co-aggregation of polysaccharide and protein with melamine due to low pH during solid-phase extraction cleanup. Limit of detection and limit of quantification values were 0.5 (mg kg?1) and 1.0 (mg kg?1) for dry samples. Overall, PLE had the best extraction efficiency compared to sonication and polytron, proving PLE to be a useful tool for melamine analysis of pet foods.  相似文献   

19.
In many countries, ractopamine hydrochloride (RAC) is allowed to be used in animal production as a β-agonist, which is an energy repartitioning agent able to offer economic benefits such as increased muscle and decreased fat deposition, feed conversion improvement and an increase in average daily weight gain. However, some countries have banned its use and established strict traceability programmes because of pharmacological implications of β-agonist residues in meat products. In Brazil, commercial RAC is controlled (5–20 mg kg?1) and only added to pig diet during the last 28 days before slaughter. However, the control is more difficult when co-products, like meat and bone meal (MBM), which can be produced from RAC treated animals, are part of the feed composition. Therefore, a study was undertaken to evaluate the presence of RAC residue concentrations in urine and tissues of gilts (n = 40) in four dietary groups: 0%, 7%, 14% and 21% (w/w) of MBM-containing RAC (53.5 µg kg?1). The concentration of RAC residues in MBM, pig tissues and urine was determined by LC–MS. Low RAC concentrations were detected in muscle, kidney, liver and lungs (limit of detection = 0.15, 0.5, 0.5 and 1.0 µg kg?1, respectively); however, no RAC residues were quantified above the limit of quantification (0.5, 2.5, 2.5 and 2.5 µg kg?1, respectively). In urine, the RAC concentration remained below 1.35 µg L?1. These data suggest that MBM (containing 53.5 µg kg?1 RAC) added to diet up to 21% (w/w) could hamper the trade where RAC is restricted or has zero-tolerance policy.  相似文献   

20.
The goal of this research was to evaluate the application of Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method for the determination of organochlorine, organophosphate, and carbamate pesticides in fatty animal matrices such as liver of chicken obtained from National Research Institute of Animal Production in Balice (Poland). Pesticides extraction effectiveness was evaluated at two different spiking levels (0.010 and 0.020 mg kg?1) and efficiency of the dispersive solid-phase extraction (d-SPE) clean-up step was evaluated by comparison adding different d-SPE sorbent combinations (PSA?+?GCB, PSA?+?C18, PSA?+?SAX, and PSA?+?NH2). The analysis of pesticide residues was performed by gas chromatography ion trap mass spectrometry (GC/IT-MS). The linear relation was observed from 0 to 400 ng mL?1 and the determination coefficient R 2?>?0.997 in all instances for all target analytes. Better recoveries were obtained in samples at 0.020 mg kg?1 spiking level. The recoveries were in the range 70–120 %, with relative standard deviation (RSD) values lower than 15 % at 0.020 mg kg?1 spiking level for most pesticides. Similar recovery ratios were obtained with the four different combinations of sorbents tested in the clean-up step, with better precision when the (PSA?+?SAX) combination was tested. Limits of detection (LODs) ranged from 0.001 to 0.005 mg kg?1 and limits of quantification (LOQs) ranged from 0.003 to 0.015 mg kg?1. The proposed method was successfully applied analyzing pesticide residues in real chicken liver samples; detectable pesticide residues were observed, but in all of the cases, the contamination level was lower than the default maximum residue levels (MRLs) set by European Union (EU), Regulation (EC) N 396/2005.  相似文献   

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