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1.
A highly selective and sensitive method was developed for the simultaneous determination of four β-agonists (clenbuterol, salbutamol, ractopamine and terbutaline) in beef by immunoaffinity chromatography purification coupled to ultra-high-performance LC-MS/MS. The MS/MS conditions, ultra-high-performance LC mobile phase, injection solution, sample purification process and matrix effect were studied to optimise the operation conditions. The limits of detection (LODs) of the instrument for the studied β-agonists ranged from 0.20 to 0.25?µg?l?1, and the LODs of the method for the studied β-agonists ranged from 0.20 to 3.00?µg?kg?1 for beef. Calibration curves were constructed using a standard solution diluted with blank beef matrix. The linear ranges of the calibration curves ranged from 5 to 100?µg?kg?1 and the coefficients of determination were >0.9942 (n?=?10) for all four β-agonists. Samples spiked at 5, 10 and 50?µg?kg?1 showed recoveries >72% and RSDs <6.6%. The method is suitable for the simultaneous detection of four β-agonists at trace levels in beef.  相似文献   

2.
A simple, new method permitting the simultaneous determination and confirmation of trace residues of 24 different growth promoters and metabolites using liquid chromatography-mass spectrometry was developed and validated. The compounds were extracted from bovine tissue using acetonitrile; sodium sulphate was also added at this stage to aid with purification. The resulting mixture was then evaporated to approximately 1?ml and subsequently centrifuged at high speed and an aliquot injected onto the LC-MS/MS system. The calculated CCα values ranged between 0.11 and 0.46?µg?kg?1; calculated CCβ were in the range 0.19–0.79?µg?kg?1. Accuracy, measurement of uncertainty, repeatability and linearity were also determined for each analyte. The analytical method was applied to a number of bovine tissue samples imported into Ireland from third countries. Levels of progesterone were found in a number of samples at concentrations ranging between 0.28 and 30.30?µg?kg?1. Levels of alpha- and beta-testosterone were also found in a number of samples at concentrations ranging between 0.22 and 8.63?µg?kg?1 and between 0.16 and 2.08?µg?kg?1 respectively.  相似文献   

3.
In total 307 egg and 275 liver samples were examined for nicarbazin and 365 eggs for diclazuril over a 30-month period. Enzyme-linked immunosorbent assay methods used for quantification were validated according to European Commission Decision 2002/657/EC. Non-compliant samples were confirmed by LC-MS/MS. Mean diclazuril concentrations in egg samples were 0.31?µg?kg?1, which is below the MRL. In only one egg sample, 2.26?µg?kg?1 was determined by enzyme-linked immunosorbent assay, although confirmation by LC-MS/MS gave a value of 1.6?µg?kg?1. Mean nicarbazin levels determined were 1.85?µg?kg?1 in egg and 21.1?µg?kg?1 in liver samples. Four samples, one egg and three livers, yielded elevated concentrations of nicarbazin, but only in the egg sample the LC-MS/MS method confirmed nicarbazin (106?µg?kg?1) above the MRL value.  相似文献   

4.
A method is reported for the analysis of sterigmatocystin in various food and feed matrices using a commercial sterigmatocystin immunoaffinity column (IAC) for sample clean-up prior to HPLC analysis by UV with mass spectrometric detection (LC-MS/MS). Cereals (wheat, oats, rye, maize and rice), sunflower seeds and animal feed were spiked with sterigmatocystin at levels from 0.75 to 50 µg kg?1 to establish method performance. Using acetonitrile/water extraction followed by IAC clean-up, and analysis by HPLC with detection at 325 nm, recoveries ranged from 68% to 106%, with repeatability from 4.2% to 17.5%. The limit of quantification with UV detection in these matrices was 1.5 µg kg?1. For the analysis of beer and cheese the sample preparation prior to IAC clean-up was changed to accommodate the different properties of the matrix, prior to analysis by LC-MS/MS. For beer and cheese spiked at 5.0 µg kg?1 the recoveries were 94% and 104%, and precision (RSDs) were 1.9% and 2.9% respectively. The limits of quantification by LC-MS/MS in beer and cheese were 0.02 and 0.6 µg kg?1 respectively. The sterigmatocystin IAC was demonstrated to provide an efficient clean-up of various matrices to enable this mycotoxin to be determined by either HPLC with UV detection or LC-MS/MS.  相似文献   

5.
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   

6.
Analysis of residual levels of tetracyclines (TCs) in chicken meat was performed using a validated liquid chromatography coupled with a tandem mass spectrometry (LC-MS/MS) technique. Overall, the recoveries for TCs ranged from 56.9% to 101.2%, with standard deviations of 4.5–13.2%. Detection limits ranged from 7.9 to 14.6?µg?kg?1. In four of 60 samples, doxycycline (DXC) was determined in a range from 19.9 to 35.6?µg?kg?1; and in one sample tetracycline was detected at 17.2?µg?kg?1. Chlortetracycline (CTC) and oxytetracycline (OTC) were not detected in any of the tested samples. This study indicates that chicken meat sold in Bursa, Turkey, contained some residues of TCs. Therefore, stricter regulations for the use of antibiotics in the poultry industry and the monitoring of drug residues in chicken meat prior to marketing are needed. Finally, this method has been applied successfully for the confirmation of TCs in chicken meat.  相似文献   

7.
Semduramicin is an ionophore coccidiostat used in the poultry industry as a feed additive. Cross-contamination of feeds for non-target animals with semduramicin is unavoidable. However, it is not known whether undesirable residues of semduramicin may occur in food after cross-contaminated feed is administered to animals. The aim of the work was to determine the levels of semduramicin in hen eggs (yolks and albumen) and tissues (liver, muscle, spleen, gizzard, ovarian yolks and ovaries) after administration of feed contaminated with 0.27 mg kg?1 of this coccidiostat. The residues were determined using LC-MS/MS. The distribution pattern confirmed the high lipophilicity of semduramicin. Residues were found mainly in egg yolks (28.8 µg kg?1), ovarian yolks (19.5 µg kg?1) and liver (2.57 µg kg?1), while hens’ muscle was free from semduramicin (LOD = 0.1 µg kg?1). Among edible tissues, the maximum level (2 µg kg?1) was exceeded only in the liver.  相似文献   

8.
A sensitive LC–MS/MS method for the simultaneous determination of type A, B and D trichothecenes in cereals is presented. The limits of detection ranged between 0.1 and 0.7 µg kg?1 for all analytes. The method was applied to 289 representatively drawn samples of wheat, rye and oat products. Ninety-four percent of the wheat samples (n = 130), 95% of the rye samples (n = 61) and 100% of the oat samples (n = 98) were contaminated with the type A trichothecenes T-2 and HT-2 toxin. Median levels of T-2/HT-2 (sum of the toxins) were 0.91, 0.53 and 8.2 µg kg?1, respectively. Highest levels were found in wheat bran (24 µg kg?1), rye kernels (3.1 µg kg?1) and oat flakes (85 µg kg?1). All wheat and rye samples and 75% of the oat samples were contaminated with the type B trichothecene deoxynivalenol. Median levels of this toxin were 23, 15 and 0.53 µg kg?1, respectively. Highest levels were found in wheat bran (1160 µg kg?1), rye kernels (288 µg kg?1) and oat flakes (55 µg kg?1). The type B trichothecene nivalenol was detected in 67% of the wheat samples, in 3% of the rye samples and in 24% of the oat samples with highest levels in wheat bran (96 µg kg?1), rye kernels (1.8 µg kg?1) and in oat flakes (17 µg kg?1), respectively. Levels of other type A and B trichothecenes played a minor role, although the rates of contamination were often high. Neither macrocyclic type D trichothecenes (satratoxin G and H, verrucarin A, roridin A) nor diacetylverrucarol and verrucarol (type A trichothecenes), were detected in any of the samples.  相似文献   

9.
A confirmatory method was developed to allow for the analysis of eleven nitroimidazoles and also chloramphenicol in milk and honey samples. These compounds are classified as A6 compounds in Annex IV of Council Regulation 2377/90 (European Commission 1990) and therefore prohibited for use in animal husbandry. Milk samples were extracted by acetonitrile with the addition of NaCl; honey samples were first dissolved in water before a similar extraction. Honey extracts underwent a hexane wash to remove impurities. Both milk and honey extracts were evaporated to dryness and reconstituted in initial mobile phase. These were then injected onto a liquid chromatography-tandem mass spectrometry (LC-MS/MS) system and analysed in less than 9 min. The MS/MS was operated in multiple reaction monitoring (MRM) mode with positive and negative electrospray ionization. The method was validated in accordance with Commission Decision 2002/657/EC and is capable of analysing metronidazole, dimetridazole, ronidazole, ipronidazole and there hydroxy metabolites hydroxymetronidazole, 2-hydroxymethyl-1-methyl-5-nitroimidazole, and hydroxyipronidazole. The method can also analyse for carnidazole, ornidazole, ternidazole, tinidazole, and chloramphenicol. A recommended level of 3 µg l?1/µg kg?1 for methods for metronidazole, dimetridazole, and ronidazole has been recommended by the Community Reference Laboratory (CRL) responsible for this substance group, and this method can easily detect all nitroimidazoles at this level. A minimum required performance level of 0.3 µg l?1/µg kg?1 is in place for chloramphenicol which the method can also easily detect. For nitroimidazoles, the decision limits (CCα) and detection capabilities (CCβ) ranged from 0.41 to 1.55 µg l?1 and from 0.70 to 2.64 µg l?1, respectively, in milk; and from 0.38 to 1.16 µg kg?1 and from 0.66 to 1.98 µg kg?1, respectively, in honey. For chloramphenicol, the values are 0.07 and 0.11 µg l?1 in milk and 0.08 and 0.13 µg kg?1 in honey. Validation criteria of accuracy, precision, repeatability, and reproducibility along with measurement uncertainty were calculated for all analytes in both matrices.  相似文献   

10.
A confirmatory and quantitative method using liquid chromatography-tandem mass spectrometry (LC-MS/MS) to determine the presence of eight glucocorticoids (prednisone, prednisolone, hydrocortisone, methylprednisolone, dexamethasone, betamethasone, beclomethasone, and fludrocortisone) in the muscles and livers of swine, cattle, and sheep and the muscle of chicken is described. After deconjugation in alkali media, samples were extracted with ethyl acetate for glucocorticoids followed by solid-phase extraction clean-up and reconstitution in the LC mobile phase. The hydrolysis procedure with sodium hydroxide was used to reduce handling time. A single-step solid-phase extraction method was optimized which is suitable for the clean-up of the compounds of interest in many diverse tissue matrices. LC separations were performed on a C18 column with gradient elution using acetonitrile and water (containing 0.2% formic acid) and the two epimers betamethasone and dexamethasone were successfully separated. LC-electrospray ionization (ESI)-MS/MS in negative mode with selected reaction monitoring (SRM) mode was performed to improve method sensitivity and reduce matrix interference. Two SRM transitions were used for each compound. The recovery of glucocorticoids spiked at levels of 0.5–16 µg kg?1 ranged from 55% to 107%; the between-day relative standard deviations were no more than 15%. The limits of quantification were 0.5–2.0 µg kg?1 in muscle and 1–4 µg kg?1 in liver. The optimized procedure was successfully applied to monitor the food at the 2008 Summer Olympics Games in Beijing, China, demonstrating the method to be simple, fast, robust, and suitable for identification and quantification of glucocorticoids residues in foods of animal origin.  相似文献   

11.
UK rye-based cereal products were analysed for six major ergot alkaloids using an in-house-validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) method that distinguished -ine and -inine epimers (isomers). Ergot alkaloids were detected in 25 of 28 samples subject to quantification limits of 1–3 µg kg?1, including all of eleven rye crispbreads that had up to 340 µg kg?1. Continental-style rye breads contained up to 121 µg kg?1. Loaf breads, bread-mix flours, and crackers contained only low levels of alkaloids. Ergotamine, ergocristine, and ergosine were the predominant ergot alkaloids in terms of level and frequency of occurrence. There were no apparent differences in the ergot levels between the organic and non-organic products, although the numbers tested were low. Most rye breads had a ratio of -ines to -inines of about 1.5, and rye crispbreads had lower and more variable -ine to -inine ratios.  相似文献   

12.
Two surveys are presented of straw analysed for naturally occurring chloramphenicol (CAP), a drug banned for use in food-producing animals. In the first study, CAP was analysed by LC-MS/MS and detected in 37 out of 105 straw samples originating from the Netherlands, France, the UK, Germany and Denmark. The highest level found was 6.3 µg kg?1, the average 0.6 µg kg?1 and the median 0.2 µg kg?1. The second study included a method comparison between ELISA and LC-MS/MS and a survey of CAP in cereal straw sampled at farms in all areas of Sweden. A total of 215 samples were screened by ELISA and a subset of 26 samples was also analysed by LC-MS/MS. Fifty-four of the samples contained more than 1 µg kg?1 CAP and the highest level found was 32 µg kg?1 (confirmed by LC-MS/MS). The highest contents of CAP in this study were allocated to the Baltic sea coast in the south-eastern part of Sweden (the county of Skåne and the Baltic Sea isle of Gotland). These results indicate a high incidence of CAP in straw in north-west Europe and have a severe impact on the enforcement of European Union legislation.  相似文献   

13.
A method for the determination of acrylamide in roasted coffee was subjected to method validation by collaborative trial. The aim was to extend the scope of a method already standardized for the determination of acrylamide in bakery and potato products to include roasted coffee. Modifications of the already standardized method were therefore kept to a minimum. The method was based on aqueous extraction of the roasted coffee matrix and solid-phase extraction (SPE) clean-up followed by isotope dilution high-performance liquid chromatography with tandem mass spectrometric detection (LC-MS/MS). The test portion of the sample was spiked with stable isotope-labelled acrylamide and extracted on a mechanical shaker with n-hexane and water for 1 h. The sample extract was centrifuged, the organic phase discarded, and a portion of the aqueous extract further cleaned-up by SPE on an Isolute Multimode cartridge followed by a second clean-up step on an Isolute ENV + cartridge. The volume of the acrylamide-containing fraction eluted from the second SPE column was reduced by evaporation and analysed by LC-MS/MS. Three coffee samples and one aqueous acrylamide standard solution were sent to eleven laboratories from eight European Union Member States. All samples were sent as blind duplicates. Based on the reported results, the relative standard deviations for reproducibility (RSDR) were 11.5% at a level of 160 µg kg?1, 10.1% at a level of 263 µg kg?1, and 9.6% at a level of 585 µg kg?1. The values for repeatability (RSDr) in those materials ranged from 1.0% to 3.5%. The method performance parameters satisfied internationally accepted criteria. Hence, the method would be suitable for the enforcement of regulatory limits.  相似文献   

14.
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   

15.
The Sulfasensor® Honey kit is a receptor test dedicated to the screening of sulphonamide residues respectively in different matrices. The aim of this project was to evaluate and validate this kit according to the Community Reference Laboratory (CRL) guideline for the validation of screening methods to achieve the French control plan for honey. The test is robust, quick (90?min for 40 samples), easy to perform and easy to read. The false-positive rate was estimated to be 12.5%. The detection capabilities CCβ of the kit were lower than or equal to 25?µg?kg?1 for sulfamethazine, sulfamerazine, sulfathiazole and sulfapyridine, and between 25 and 50?µg?kg?1 for sulfadiazine and sulfadimethoxine, 150?µg?kg?1 for sulfaquinoxaline, and 1000?µg?kg?1 for sulfamethoxazole and sulfamethizole. Sulfanilamide was not detected by the kit. The kit was applicable to a wide variety of honeys (different floral and geographical origins, liquid or solid). This kit was used to implement the French control plan for the detection of antibiotic residues in honey in 2010 in parallel with an HPLC method. However, in 2011 the kit was replaced by an LC-MS/MS method for the screening and confirmation of sulfonamide residues in honey, which detects all the sulfonamides of interest.  相似文献   

16.
Different cheese samples produced in Latvia (eight) and Belgium (13) were analysed for their sterigmatocystin (STC) content. Only two (9.5%) of the samples were positive for STC with concentration levels of 1.23 and 0.52 µg kg?1, respectively. Five (24%) samples contained STC above the limit of detection (0.03 µg kg?1) but below the limit of quantification (0.1 µg kg?1), A sensitive liquid chromatography-electrospray positive ionisation-tandem mass spectrometry (LC-MS/MS) method, which was previously developed for the analysis of STC in grains, was modified and applied to the analysis of STC in cheese. This method involved sample extraction with acetonitrile–water (90 : 10, v/v), defatting with n-hexane, solid-phase extraction, separation on a reversed-phase C18 column, and STC detection by LC-MS/MS.  相似文献   

17.
The aim of this study was to develop a simple high-performance liquid chromatography (HPLC) with UV detection method for the determination of four sulfonamides in chicken muscle tissue. The sulfonamides were extracted with acetonitrile, acetone and dichloromethane. Separation was carried out on a C18 column using as the mobile phase a mixture of 6‰ disodium hydrogen phosphate and methanol. The analytes were detected by UV in one run. Calibration curves were linear with very good correlation coefficients for concentration ranging from 30 to 150?µg?kg?1. The limits of detection (LOD) for sulfonamides ranged from 6.5 to 0.14?µg?kg?1. The recovery for spiked chicken muscle with 50–150?µg?kg?1 was more than 70%. The relative standard deviations (RSDs) of the sulfonamides for six measurements at 50, 100 and 150?µg?kg?1 were less than 15%. These parameters met the European Union criteria for method validation. The results were confirmed by LC-MS/MS using multiple reaction monitoring as the operating mode. Confirmation required the retention times of the analytes to be within ±2.5% of the retention times of the standards, the presence of the parent ion and two characteristic fragment ions (product ions) per analyte, as well as the relative ion abundance ratios of the fragment ions corresponding to ratios obtained for the standards, within permitted limits. The transition of two common product ions at m/z 155.7 and 107.5 were monitored for all sulfonamides. Each of the analytes, in all tested samples, met the confirmation criteria. Thus, the applicability of the HPLC-UV method for routine analysis of chicken muscle tissue was demonstrated.  相似文献   

18.
Tetracyclines are extensively used in veterinary medicine. For the detection of tetracycline residues in animal products, a broad array of methods is available. Luminescent bacterial biosensors represent an attractive inexpensive, simple and fast method for screening large numbers of samples. A previously developed cell-biosensor method was subjected to an evaluation study using over 300 routine poultry samples and the results were compared with a microbial inhibition test. The cell-biosensor assay yielded many more suspect samples, 10.2% versus 2% with the inhibition test, which all could be confirmed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Only one sample contained a concentration above the maximum residue limit (MRL) of 100 µg kg?1, while residue levels in most of the suspect samples were very low (<10 µg kg?1). The method appeared to be specific and robust. Using an experimental set-up comprising the analysis of a series of three sample dilutions allowed an appropriate cut-off for confirmatory analysis, limiting the number of samples and requiring further analysis to a minimum.  相似文献   

19.
ABSTRACT

An efficient, sensitive, simple and fast method for the simultaneous determination of oxine-copper and pyraclostrobin in citrus fruit was developed and validated. The method uses ethylene diamine tetra-acetic acid as a competitive ligand to convert oxine-copper to soluble 8-hydroxyquinoline for analysis by QuEChERS and LC-MS/MS. Linear relationships were determined with correlation coefficients ranging from 0.9904 to 0.9998. The limits of detection for the analytes were 0.012–0.8 μg kg?1, and the limits of quantitation were 0.04–2.6 μg kg?1 in citrus. The average recoveries were 79.1–114.9% with relative standard deviations of less than 7.4%. The analyses of dissipation indicated that the half-lives of oxine-copper and pyraclostrobin were 1.94–3.67 and 1.79–2.48 days and the terminal residues were <0.08–8.99 and <0.02–1.90 mg kg?1, respectively. The risk quotients of oxine-copper and pyraclostrobin were 0.026–0.199 and 0.003–0.022, respectively. This risk assessment provides a reference for the safe and reasonable use of oxine-copper and pyraclostrobin and may help to establish maximum residue limits for these pesticides in China.  相似文献   

20.
ABSTRACT

An ultra-high-performance liquid chromatography–tandem mass spectrometry (UHPLC-MS/MS) based multiclass multi-residue method for the simultaneous analysis of 5 polyether ionophores, 4 tetracycline and 10 sulfonamides in animal and aquaculture fish tissues was developed and validated. Sample extraction and clean-up were based on a modified QuEChERS method. The method was validated using an in-house validation based on performance characteristics modified from Commission Decision 2002/657/EC. Both matrix effect and uncertainties associated with sample preparation and instrumental analysis were minimised by the use of matrix-matched calibrations. Recoveries of analytes were generally satisfactory and typically fell between 80% and 113%. The repeatability and intermediate reproducibility measured as relative standard deviations were in most cases less than 15% (n = 63). The decision limit (CCα) and detection capability (CCβ) ranged from 110.7 to 125.8 and 121.5 to 151.7 µg kg?1 for tetracyclines, 113.4 to 118.3 and 116.8 to 126.5 µg kg?1 for sulfonamides and 50.8 to 52.4 and 51.5 to 55.6 µg kg?1 for polyether ionophores, respectively. The method displayed its fitness for purpose through satisfactory results obtained in international proficiency testing schemes. The method was applied to animal and aquaculture fish tissues obtained from different sources in South Africa. Polyether ionophores were predominantly detected in samples in the range 4.26–290.10 µg/kg. Oxytetracycline was found in one porcine liver sample; however, none of the targeted analytes were present above the detection limit in the aquaculture samples.  相似文献   

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