首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
A rapid, high-throughput method employing ultra-performance liquid chromatography with tandem quadrupole mass spectrometry (UPLC-MS/MS) was developed and optimized for simultaneous quantification and confirmation of 64 pesticide residues and their toxic metabolites in fruit extracts prepared by a buffered QuEChERS procedure. The total time required for UPLC-MS/MS analysis was 8 min plus 2 min for re-equilibration to the initial UPLC conditions. Performance characteristics were determined for apple extracts spiked at 10 µg kg?1. The repeatability of measurements expressed as relative standard deviations was in the range 1.5–13% at this level for most analytes. Thanks to very low limits of quantification (<10 µg kg?1for the majority of pesticides), an optimized method allows for the reliable control of not only common maximum residue limits (MRLs) set by European Union regulation for various pesticides/fruit combinations, but also of a uniform MRL of 10 µg kg?1endorsed for baby food.  相似文献   

2.
The aim of this study was to determine the level of organochlorine (OC) pesticides in 57 samples of canned tuna and 31 samples of canned sardines in vegetable oil, collected from supermarkets in Serbia. OC pesticides α-HCH, β-HCH, δ-HCH, dichlorodiphenyltrichloroethane (DDT), DDE, DDD, dielderin, endosulfane I, endosulfane II, endosulan sulfate, endrin, endrin ketone, heptachlor, heptachlor epoxide, lindane, aldrin, metoxichlor, cis-chlordane and trans-chlordane were determined using a GS-MS method. The highest concentrations (µg kg?1, arithmetic means) in canned tuna were for δ-HCH (60.6 ± 97.0) and p, p´-DDT (55.0 ± 25.1), while the corresponding values in canned sardines were for δ-HCH (90.7 ± 102.7) and endosulfane II (78.0 ± 145.9). Mean level for the sum of endosulfans was above the maximum limit in canned sardines (85.0 µg kg?1). Also, dieldrin (39.7 µg kg?1) was measured above the ML.  相似文献   

3.
This paper describes a comparison of adaptations of the QuEChERS (quick, easy, cheap, effective, rugged and safe) approach for the determination of 14 organochlorine pesticide (OCP) residues in strawberry jam by concurrent use of gas chromatography (GC) coupled to electron capture detector (ECD) and GC tandem mass spectrometry (GC-MS/MS). Three versions were tested based on the original QuEChERS method. The results were good (overall average of 89% recoveries with 15% RSD) using the ultrasonic bath at five spiked levels. Performance characteristics, such as accuracy, precision, linear range, limits of detection (LOD) and quantification (LOQ), were determined for each pesticide. LOD ranged from 0.8 to 8.9?µg?kg?1; LOQ was in the range of 2.5–29.8?µg?kg?1; and calibration curves were linear (r 2?>?0.9970) in the whole range of the explored concentrations (5–100?µg?kg?1). The LODs of these pesticides were much lower than the maximum residue levels (MRLs) allowed in Europe for strawberries. The method was successfully applied to the quantification of OCP in commercially available jams. The OCPs were detected lower than the LOD.  相似文献   

4.
In this study, levels of several groups of environmental contaminants represented by PAHs, PCBs, organochlorine pesticides and polybrominated diphenyl ethers were determined in various types of canned smoked and non-smoked fish and seafood products (54 samples) obtained from the Czech market. PAHs were detected in all of the studied samples, and at least one of the target halogenated persistent organic pollutants was present above the LOQ in 85% of the samples. The levels of PAHs, PCBs, organochlorine pesticides (mainly DDTs) and polybrominated diphenyl ethers found in the canned products varied in the range of 1.4–116?µg?kg?1, 0.6–59.6?µg?kg?1, 0.6–82.7?µg?kg?1 and 0.1–2.1?µg?kg?1 can content, respectively. Smoked sprats were the most contaminated fish product (n?=?12) in which the highest levels of both PAHs and persistent organic pollutants were found. In 67% of the samples of smoked sprats in oil, the level of benzo[a]pyrene exceeded the maximum level of 5?µg?kg?1 established for smoked fish by European Union legislation. The distribution of target analytes between oil and fish fractions was also assessed. Significantly higher levels of PAHs were measured in the oil fraction.  相似文献   

5.
In Mexico, maize tortillas are consumed on a daily basis, leading to possible aflatoxin exposure. In a survey of 396 2-kg samples, taken over four sampling days in 2006 and 2007 from tortilla shops and supermarkets in Mexico City, aflatoxin levels were quantified by HPLC. In Mexico, the regulatory limit is 12?µg?kg?1 total aflatoxins for maize tortillas. In this survey, 17% of tortillas contained aflatoxins at levels of 3–385?µg?kg?1 or values below the limit of quantification (<LOQ) and, of these, 13% were >12?µg?kg?1 and 87% were below the regulatory limit. Average aflatoxin concentrations in 56 contaminated samples were: AFB1 (12.1?µg?kg?1); AFB2 (2.7?µg?kg?1); AFG1 (64.1?µg?kg?1) and AFG2 (3.7?µg?kg?1), and total AF (20.3?µg?kg?1).  相似文献   

6.
The aim of this study was to assess mycotoxin contamination of crops grown by rural subsistence farmers over two seasons (2011 and 2012) in two districts, Vhembe District Municipality (VDM, Limpopo Province) and Gert Sibande District Municiality (GSDM, Mpumalanga Province), in northern South Africa and to evaluate its impact on farmers’ productivity and human and animal health. A total of 114 maize samples were collected from 39 households over the two seasons and were analysed using a validated liquid chromatography-tandem mass spectrometry mycotoxins method. Aflatoxin B1 (AFB1) occurrence ranged from 1 to 133 µg kg?1 in VDM while AFB1 levels in GSDM were less than 1.0 µg kg?1 in all maize samples. Fumonisin B1 levels ranged from 12 to 8514 µg kg?1 (VDM) and 11–18924 µg kg?1 (GSDM) in 92% and 47% positive samples, respectively, over both seasons. Natural occurrence and contamination with both fumonisins and aflatoxins in stored home-grown maize from VDM was significantly (p < 0.0001) higher than from GSDM over both seasons.  相似文献   

7.
The content of residual organochlorine pesticides (OCPs) was examined in green, herbal, and black tea leaves as well as in their infusions prepared from tea products marketed in the main supermarkets in Poland. It was found that the detected mean levels of organochlorine residues in tea leaves ranged from ?1 dry weight. Among hexachlorocyclohexane isomers, γ-HCH in green tea occurred in the highest concentrations. Among dichlorodiphenyltrichloroethane (DDT) metabolites the highest level of p,p′DDT (1.96 ng g?1 dw) was in green tea samples. The transfer of OCPs from tea leaves to brew was investigated. The present study revealed that during the infusion process, a significant percentage of the residues, particularly pesticides with high water solubility, were transferred to the infusions. The obtained results show that the percentage transfer of each pesticides from tea to the tea infusions ranged from 6.74% (heptachlor) to 86.6% (endrin). The detected residues were below current MRLs for these pesticides.  相似文献   

8.
Animals intended for human food may absorb pesticides from residues in their feed, water or during direct/indirect exposure in the course of pest control. The objective of the present investigation was to monitor organochlorine pesticide residues in poultry feed, chicken muscle and eggs at a selected poultry farm. The samples were Soxhlet extracted for 8 h in 200 mL hexane–acetone (1:1, v/v) mixture. The clean‐up of the samples was performed by silica gel column chromatography and analysis was done on a gas chromatograph equipped with an electron capture detector. The mean total hexachlorocyclohexane (HCH) and dichlorodiphenyltrichloroethane (DDT), endosulfan sulfate and heptachlor epoxide residues were 0.65, 0.91, 0.42 and 0.02 mg kg?1, respectively, in feed while respective values for chicken muscle were 0.11, 0.24, 0.10 and 0.07 mg kg?1. Higher residues were encountered in eggs as compared to muscle. None of the muscle samples exceeded maximum residue limits (MRL) for organochlorine pesticides, while all egg samples had values above the MRL for HCH and heptachlor epoxide and seven egg samples exceeded MRL for DDT residues. The results indicated that poultry feed could be one of the major sources of contamination for chicken and eggs. These residues are present despite complete ban on the use of technical HCH and DDT for agricultural purposes in India. Copyright © 2005 Society of Chemical Industry  相似文献   

9.
The aims of the study were to obtain information about the occurrence of ochratoxin A (OTA) and citrinin (CIT) in cereals harvested in the Czech Republic and to compare two analytical procedures for detecting OTA. A total of 34 cereal samples, including two matrix reference materials (R-Biopharm, Germany), were analysed. The results were compared with the limit for raw cereal grains used as a foodstuff according to Commission Regulation No. 1881/2006, which allows a maximum OTA level of 5 µg kg?1. Compared were two methods based on the high-performance liquid chromatography principle, one using the immunoaffinity columns OchraTest? (VICAM) and the second based on solvent partition (PART), both followed by fluorescence detection. The highest OTA contents were found in two barley samples. According to the method employed, the results for the first sample (malting barley) were VICAM = 31.43 µg kg?1 and PART = 44.74 µg kg?1. For the second sample (feeding barley) they were VICAM = 48.63 µg kg?1 and PART = 34.40 µg kg?1. Two samples of bread wheat had an OTA content approaching the legal limit (VICAM = 4.71 µg kg?1 and PART = 6.03 µg kg?1; VICAM = 4.12 µg kg?1 and PART = 3.95 µg kg?1). CIT was analysed using the PART method only, and its highest content (93.64 µg kg?1) was found for the malting barley sample with high OTA content (44.74 µg kg?1 as analysed using PART).  相似文献   

10.
In northern Cameroon, the misuse of pesticides for pest control is common among small-scale farmers. Therefore, monitoring of pesticide residues was carried out on stored maize, cowpea and millet from eight localities. The determination of residues of organochlorines (lindane, α-endosulfan and β-endosulfan), organophosphorus compounds (malathion and pirimiphos-methyl), synthetic pyrethroids (permethrin) and carbamates (carbufuran) was performed using GC–ECD/NPD and GC–MS for confirmation. Organochlorine pesticides were detected more frequently and in higher concentrations, ranging from 0.02 ± 0.01 mg kg?1 for β-endosulfan in millet to 9.53 ± 4.00 mg kg?1 lindane in maize, than organophosphorus compounds, with concentrations varying from 0.04 ± 0.03 mg kg?1 for pirimiphos methyl to 0.23 ± 0.38 mg kg?1 for malathion in maize. Permethrin was found only in maize at 0.39 ± 0.23 mg kg?1. No carbofuran was found. More than 75% of samples contained pesticide residues above the maximum residue limit (MRL); showing a potential human dietary risk related to consumption of these grains.  相似文献   

11.
The aim was to evaluate the distribution of aflatoxins and fumonisins in fractions derived from the dry-milling of contaminated maize. Two maize lots with different contamination levels were processed and sampled: the first (maize 1) had aflatoxin B1 (AFB1) and fumonisin B1 (FB1) levels of 3.6 and 5379 µg kg?1, respectively; the second (maize 2) had corresponding levels of 91.1 and 8841 µg kg?1, respectively. The cleaning step reduced AFB1 and FB1 levels by 8 and 11% in maize 1 and by 57 and 34% in maize 2. The subsequent removal of bran and germ led to a further decrease in contamination levels in the products destined for human consumption. In the latter, AFB1 was uniformly distributed, while FB1 was concentrated in the finer size fractions. Contamination of raw maize 1 (3.6 µg kg?1) was below the European Union AFB1 limit of 5 µg kg?1 for unprocessed maize, but among the final products only coarse flour (1.7 µg kg?1) was within the European Union limit of 2 µg kg?1, while grits and fine flour showed higher levels (2.7 and 2.5 µg kg?1, respectively). As regards cleaned maize, a different distribution of the two toxins was observed in the kernels: AFB1 contamination was more superficial and concentrated in germ, while FB1 contamination affected the inner layers of the kernels.  相似文献   

12.
Methylmercury intake for adult males of twelve provinces in China was estimated by means of the 2007 Chinese Total Diet Study. Methylmercury levels were measured in twelve food groups of each province of four regions and was only found in the aquatic food groups. The range for methylmercury contents of aquatic foods was 3.29–31.60?µg?kg?1, being 50–87% of total mercury. Methylmercury intakes from aquatic foods for adult males of twelve provinces ranged from 0.003 to 0.138?µg?kg?1?bw?week?1 with average of 0.041?µg?kg?1?bw?week?1, which were estimated according to methylmercury contents and corresponding aquatic food consumption. Methylmercury intakes for the Chinese population were far below the corresponding provisional tolerable weekly intake (PTWI), which was established by the Joint FAO/WHO Expert Committee on Food Additives (JECFA). Consequently, there was little health risk from methylmercury exposure for the average Chinese population.  相似文献   

13.
A gas chromatography-mass spectrometry (GC-MS) method was developed for the analysis of 15 polycyclic aromatic hydrocarbons (PAHs) highlighted as carcinogenic by the Scientific Committee on Food (SCF) plus benzo[c]fluorine (recommended to be analysed by the Joint FAO/WHO Expert Committee on Food Additives (JECFA)) in fat-containing foods such as edible oils and smoked meat products. This method includes accelerated solvent extraction (ASE) and the highly automated clean-up steps gel permeation chromatography (GPC) and solid-phase extraction (SPE). Using a VF-17ms GC column, a good separation of benzo[b]fluoranthene, benzo[j]fluoranthene and benzo[k]fluoranthene was achieved. Furthermore, the six methylchrysene isomers and the PAH compounds with a molecular weight of 302 Daltons in fat-containing foods attained a better chromatographic separation in comparison with a 5-ms column. The reliability of the analytical method for edible oils was demonstrated by the results from a proficiency test. Measurements with GC-high-resolution mass spectroscopy (HRMS) and gas chromatography-mass selective detection (GC-MSD) led to comparable results. A survey of the 16 PAHs in 22 smoked meat products showed concentrations in the range <0.01–19 µg kg?1. The median concentration for benzo[a]pyrene was below 0.15 µg kg?1.  相似文献   

14.
Quality aspects of oysters (Crassostrea gigas) from a suspended culture in the lagoon of Venice (Valle Dogà) were examined in different seasons over a 1‐year period. Ecophysiological and commercial quality indicators (condition index, content of meat, shell and intervalvar fluid), nutritional quality parameters (proximate and mineral composition, glycogen content, fatty acid profile, cholesterol, plant sterols, fat‐soluble vitamins content) and levels of organic pollutants (polychlorinated biphenyls and organochlorine pesticides) were determined at different times of the year. Seasonal variations were observed in the nutrient content, with particular regard to moisture (ranging from 866.8 g kg?1 in June to 938.8 g kg?1 in September), protein (23.9 g kg?1 in September to 76.6 g kg?1 in June), ash (22.5 g kg?1 in February to 29.5 g kg?1 in July), lipid (3.0 g kg?1 in September to 8.8 g kg?1 in June) and glycogen (0.7 g kg?1 in September to 11.5 g kg?1 in February). In spite of this variability, the nutritional quality of the oysters was generally good, especially just before gamete release when the concentration of nutrients was at its maximum. Low levels of organochlorine chemicals were detected in the edible meat of oysters but, because only a limited number of samples were analysed, no general conclusion can be drawn on the safety of seafood from this area. Copyright © 2004 Society of Chemical Industry  相似文献   

15.
In 367 domestic fowl (Gallus domesticus) eggs collected from 61 farms, residues of 10 pesticides were detected in various combinations and in the following order of frequency: p,p′-DDE (in 100% of the eggs), p,p′-DDT (98%), dieldrin (95%), Indiane (66%), p,p′-DDD (46%), o,p′-DDT (17%), β-HCH (9%), γ-HCH (5%), endrin (4%) and aldrin (0–5%). No residues of heptachlor, heptachlor epoxide, HCB or PCBs were found. The mean concentration (0–70 mg kg?1 eggs; range <0–01–10–25) of total DDT exceeded the extraneous residue limit (ERL) of 0–50 mg kg?1. The mean dieldrin residue level (0–35 mg kg?1; range 0–01–14–90) was 3–5 times higher than the ERL (0–10 mg kg?1). Only 3% of the eggs exceeded the ERL for Indane. The 156 eggs from free-range hens had significantly (P<0–05) higher residue concentrations of total DDT, dieldrin and Iindane than eggs collected from hens kept in enclosures. The mean ratio [p,p′-DDT]/[p,p′-DDE] in eggs from enclosed hens (0–97) was significantly higher (P<0–01) than in eggs from free-range hens (0–53), indicating that the former had a more direct exposure to p,p′-DDT, whereas the latter obtained more of it after environmental conversion to p,p′-DDE. Eggs from a rice-growing area had the highest concentrations of all pesticide residues detected. Accumulation ratios indicated that the levels of DDT and Iindane in the feed of enclosed hens could account for the levels in the corresponding eggs. The much higher accumulation ratios calculated for the free-range hens demonstrated that the feed ingested by these chickens obviously contained ingredients additional to those sampled, and revealed probable extensive environmental contamination by these persistent pesticides. The present results indicate that there is a need to identify sources of dieldrin in the eggs of domestic fowls and, where necessary to investigate local wildlife samples. The amounts of total DDT and dieldrin in eggs in this study seem to be higher than reported from any other country. Toxicological evaluation of the results indicates that, at lest in parts of KEnya there is a need for improved practices in the use of some organochlorine pesticides.  相似文献   

16.
The aim of this research was to determine the fate of aflatoxins (AFs) and fumonisins (FBs) naturally occurring in raw materials (maize grit and malted barley) during four industrial brewing processes. The aflatoxin B1 (AFB1) level in raw materials varied from 0.31 to 14.85 µg kg?1, while the fumonisin B1 (FB1) level (only in maize grit) varied from 1146 to 3194 µg kg?1. The concentration in finished beer ranged from 0.0015 to 0.022 µg l?1 for AFB1 and from 37 to 89 µg l?1 for FB1; the other aflatoxins and fumonisin B2 were not found in beer samples. The average percentage of toxins recovered in finished beer, referring to the amounts contained in raw materials, were 1.5% ± 0.8% for AFB1 and 50.7% ± 4.7% for FB1. These results were mainly due to the different solubility of the two mycotoxins during the mashing process. If raw materials comply with the limits fixed by European Commission Regulations, the contribution of a moderate daily consumption of beer to AFB1 and FB1 intake does not contribute significantly to the exposure of the consumer.  相似文献   

17.
Di-(2-ethylhexyl) phthalate (DEHP) concentrations in the atmosphere and in four vegetable crops including Brassica chinensis L. (bok choy), Brassica campestris L. (field mustard), Vigna unguiculata Walp. (cowpea), and Solanum melongena L. (eggplant) cultivated on land surrounding a plastic production factory were determined. The air DEHP concentrations (means) at the sites 0.2, 0.4, 0.8, and 1.6 km away from the plastic production building were about 9.4–12.8, 5.8–9.6, 1.6–5.0, and 0.04–0.27 µg m?3 dry weight (DW), respectively. Wind direction is a key factor influencing the measurable DEHP concentration of the air, which was highest in the downwind direction and lowest in the upwind direction, and thus the vegetables accumulated the highest DEHP contents in the downwind direction and the lowest quantities in the upwind direction. The highest DEHP accumulations content of bok choy, field mustard, eggplant, and cowpea were 52.0 ± 3.1, 43.1 ± 2.2, 36.2 ± 2.8, and 19.4 ± 0.47 mg kg?1 DW, respectively. Safety estimation on the basis of the daily intake limit referenced by the US Environmental Protection Agency (USEPA) led to the conclusion that eating vegetables cultivated 0.2 km away from the plastic production building is not a food safety problem under normal conditions. A strong positive linear correlation between atmospheric DEHP concentration and DEHP content of the vegetable crops was found. The limits for air DEHP concentration for safe vegetable cultivation are 24.0, 34.8, 40.8, and 82.8 µg m?3 for bok choy, field mustard, cowpea, and eggplant, respectively, by calculating from the equation of linear regression between air DEHP concentration and vegetable DEHP content.  相似文献   

18.
Dietary exposure of the Valencia Region population to polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and PCBs was assessed in the Region of Valencia in 2010–2011. A total of 7700 food samples were collected. Occurrence data were combined with consumption data to estimate dietary exposure in adults (>15 years of age) and young people (6–15 years of age). The estimated intake was calculated by a probabilistic approach. Average intake levels (upper-bound scenario) were 1.58 and 2.76 pg toxic equivalent (TEQ) kg?1 body weight (bw) day?1 for adults and young people, respectively. These average intakes are within range of the tolerable daily intake of 1–4 pg WHO-TEQ kg?1 bw day?1 recommended by WHO, and slightly above the tolerable weekly intake (TWI) of 14 pg TEQ kg?1 bw week?1 and the Provisional tolerable monthly intake of 70 pg TEQ kg?1 bw month?1 set by the Scientific Committee on Food and the Joint FAO/WHO Expert Committee on Food, respectively. These results show that the contamination levels in food and therefore the exposure of the general population to PCDD/Fs and PCBs have declined in this region and therefore show the efficiency of the European risk-management measures. In terms of risk characterisation, the results showed that, under the upper-bound scenario, 22% of the adult and 58% of the young people population could exceed the TWI.  相似文献   

19.
This study determined maize-user practices that influence the presence of fumonisin and aflatoxin contamination of maize in food consumed in the rural areas of Tanzania. Samples of the 2005 maize harvest in Tanzania were collected from 120 households and examined for fumonisins and aflatoxins. Information on whether the maize was sorted to remove defective (visibly damaged or mouldy) maize before storage and whether the damaged and mouldy maize or the non-dehulled maize was used as food was also collected. In addition, the percentage of defective kernels in the samples was determined. Ninety per cent of the households sorted out defective maize, 45% consumed the defective maize and 30% consumed non-dehulled maize. In 52% of the samples fumonisins were determined at levels up to 11,048 µg kg?1 (median = 363 µg kg?1) and in 15% exceeded 1000 µg kg?1; the maximum tolerable limit (MTL) for fumonisins in maize for human consumption in other countries. Aflatoxins were detected in 18% of the samples at levels up to 158 µg kg?1 (median = 24 µg kg?1). Twelve per cent of the samples exceeded the Tanzanian limit for total aflatoxins (10 µg kg?1). Aflatoxins co-occurred with fumonisins in 10% of the samples. The percentage defective kernels (mean = 22%) correlated positively (r = 0.39) with the fumonisin levels. Tanzanians are at a risk of exposure to fumonisins and aflatoxins in maize. There is a need for further research on fumonisin and aflatoxin exposure in Tanzania to develop appropriate control strategies.  相似文献   

20.
Estimating the risk associated with dietary intake of heavy metals by consumers is a vital and integral part of regulatory processes. The assessment of exposure to mercury shown in this paper has been performed by means of a study on the whole diet. Total mercury (Hg) levels were determined by cold vapour atomic absorption spectrometry (AAS) in 420 samples of regularly consumed food and drink. The total Hg concentrations measured in the different groups of food ranged from non-detectable to 119 µg kg?1 w/w. The fish group had the highest concentrations of total Hg. All groups of food with regulated Hg content showed levels that were lower than the legally set values. The food consumption data used in the analysis were taken from the latest nutritional survey made in the Canary Islands, Spain. The estimated total Hg intake of local population (5.7 µg/person day?1) did not exceed the provisional tolerable weekly intake (PTWI) limit of 0.3 mg week?1 of total mercury (43 µg/person day?1) fixed by the Joint Food and Agricultural Organization/World Health Organization (FAO/WHO) Expert Committee on Food Additives. Fishery products contributed 96% of the total Hg intake. The mean Hg intake for each island in this archipelago, formed by seven, has also been calculated. Fuerteventura, Lanzarote and El Hierro are the islands with the highest level of Hg intake (7.0, 7,0 and 6.1 µg/person day?1, respectively). La Palma Island, due to its low fish consumption, had the lowest level of Hg intake (4.5 µg/person day?1), followed by La Gomera (5.4 µg/person day?1), Tenerife (5.5 µg/person day?1) and Gran Canaria (5.6 µg/person day?1). A comparison has been made of the results obtained in this study with those found for other national and international communities.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号