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1.
The further optimization and validation of a multiresidue veterinary drug screening method for milk is described. The drug residues of regulatory interest in milk include beta-lactams, sulfonamides, tetracyclines, fluoroquinolones, and macrolides. A previously published procedure has been modified to incorporate new compounds and to collect both screening and confirmatory ion transitions in one acquisition method. Milk samples were extracted with an equal volume of acetonitrile. The samples were then subjected to cleanup with a bonded SPE cartridge and a MW cutoff filter. The SPE protocol was modified to effectively recover a metabolite of flunixin. Established tolerance levels are set for most of these drugs in milk; thus, the screening procedure was semiquantitative, using positive controls for comparison. The positive controls, consisting of extracts from milk fortified with the drugs at their tolerance or safe level, were used to set statistically valid minimum response criteria for unknown samples. This updated method was validated with fortified milk, as well as with milk samples from animals administered veterinary drugs.  相似文献   

2.
Two rapid multi-residue screening methods for the determination of 21 veterinary drugs in milk by ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) have been developed and compared. For both methods, veterinary drugs were extracted from milk samples using a rapid extraction procedure based on the modification of the well-known QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) method, and no further clean-up steps were necessary. One screening method was based on the selection of a characteristic neutral loss or product ion of the various families of compounds, whereas another one was based on the choice of a selected reaction monitoring (SRM) for each compound. These methods were compared with regards to false negatives, cut-off values and the unreliability region. The total run time for both methods was 3 min, allowing quick selection of samples that contained veterinary drugs. Non-negative samples were re-analyzed by the UHPLC-MS/MS confirmation/quantification method, which consisted in the monitoring of two SRM for each compound. The methods were validated according to international guides. The proposed analytical methods allow for the identification and confirmation of the target veterinary drugs at trace levels employing quick analysis time.  相似文献   

3.
There is an increasing interest in screening methods for quick and sensitive analysis of various classes of veterinary drugs with limited sample pre-treatment. Turbulent flow chromatography in combination with tandem mass spectrometry has been applied for the first time as an efficient screening method in routine analysis of milk samples. Eight veterinary drugs, belonging to seven different classes were selected for this study. After developing and optimising the method, parameters such as linearity, repeatability, matrix effects and carry-over were studied. The screening method was then tested in the routine analysis of 12 raw milk samples. Even without internal standards, the linearity of the method was found to be good in the concentration range of 50 to 500 μg/L. Regarding repeatability, RSDs below 12% were obtained for all analytes, with only a few exceptions. The limits of detection were between 0.1 and 5.2 μg/L, far below the maximum residue levels for milk set by the EU regulations. While matrix effects—ion suppression or enhancement—are obtained for all the analytes the method has proved to be useful for screening purposes because of its sensitivity, linearity and repeatability. Furthermore, when performing the routine analysis of the raw milk samples, no false positive or negative results were obtained.  相似文献   

4.
New approaches to veterinary drug screening based on liquid chromatography-mass spectrometry (LC-MS/MS) and time-of-flight mass spectrometry (ToF/MS) are rapid and have high selectivity and sensitivity. In this study, we developed a multiresidue method for screening over 100 veterinary drug residues using ion trap (IT)-ToF/MS. The screened compounds comprised major drug classes used in veterinary practice, representing the following: amphenicols, anthelmintics, benzimidazoles, β-lactams, coccidiostats, ionophores, macrolides, non-steroidal anti-inflammatory drugs, quinolones, sulfonamides, tetracyclines, and tranquilizers. The method was developed based on chromatographic retention time, specific accurate mass, isotope distribution, and fragment data. Each compound was validated at three levels, and the mass accuracy, accuracy, and repeatability were calculated. All parameters showed acceptable values and conformed to the Commission Decision 2002/657/EC criteria. This screening method can simultaneously analyze over 100 veterinary drugs in meat, milk, eggs, and fish in a single analytical run.  相似文献   

5.
Veterinary drugs (VDs) can remain in milk as a consequence of their use in livestock. In order to control the levels of VD residues in milk, screening methodologies can be applied for a rapid discrimination among negative and non-negative samples. In a second stage, non-negative samples are classified as negative or positive samples by using a confirmation method. Pre-target screening methods in low resolution MS (LRMS) are normally applied, but the number of analytes is limited, whereas the information obtained by full scan acquisition in high resolution mass spectrometry (HRMS) is improved. Here, three screening methods (running time<4 min) based on Orbitrap, quadrupole-time of flight (QqTOF) and triple quadrupole (QqQ) have been compared, using in all cases ultra-high performance liquid chromatography (UHPLC). For HRMS, the identification of the VDs was based on retention time (RT) and accurate mass measurements. Confirmation was based on the monitoring of fragments generated without precursor selection. The performance characteristics of the screening method provided reliable information regarding the presence or absence of the compounds below an established value, including uncertainty region and cut-off values. Better results in terms of cut-off values (≤ 5.0 μg kg(-1), except for spiramycin with a cut-off of 13.4 μg kg(-1) for milk samples and 43.1 μg kg(-1) for powdered milk based, emamectin with a cut-off of 42.2 μg kg(-1) for milk samples and doxycycline, with a cut-off value of 15.8 μg kg(-1) in powdered milk-based infant formulae) and uncertainty region were obtained using the Orbitrap-based screening method, which was submitted to further validation and used to analyze different real milk samples. The proposed method can be used in routine analysis, providing reliable results.  相似文献   

6.
A new multi-target screening (MTS) procedure for drugs in blood and urine for toxicological analysis has been developed using a hybrid triple-quadrupole linear ion trap mass spectrometer (QTrap) for the fast detection and identification of 301 forensically important drugs, e.g. tranquilizers (benzodiazepines), hypnotics, drugs of abuse (opiates, cocaine, amphetamines, cannabinoids), antidepressants, neuroleptics, and some cardiac drugs, in one single liquid chromatography/tandem mass spectrometry (LC/MS/MS) analysis. Samples were extracted either with liquid-liquid extraction or solid-phase extraction. A multiple reaction monitoring (MRM) as survey scan and an enhanced product ion (EPI) scan as dependent scan were performed in an information-dependent acquisition (IDA) experiment. Finally, drug identification was carried out by library search with a newly developed MS/MS library based on EPI spectra at three different collision energies in positive mode. The advantage of this newly developed method is the possibility to detect and identify 301 drugs in one single LC/MS/MS run.  相似文献   

7.
Ultra-performance liquid chromatography combined with time-of-flight mass spectrometry (UPLC–ToF-MS) has been used for screening and quantification of more than 100 veterinary drugs in milk. The veterinary drugs represent different classes including benzimidazoles, macrolides, penicillins, quinolones, sulphonamides, pyrimidines, tetracylines, nitroimidazoles, tranquillizers, ionophores, amphenicols and non-steroidal anti-inflammatory agents (NSAIDs). After protein precipitation, centrifugation and solid-phase extraction (SPE), the extracts were analysed by UPLC–ToF-MS. From the acquired full scan data the drug-specific ions were extracted for construction of the chromatograms and evaluation of the results. The analytical method was validated according to the EU guidelines (2002/657/EC) for a quantitative screening method. At the concentration level of interest (MRL level) the results for repeatability (%RSD < 20% for 86% of the compounds), reproducibility (%RSD < 40% for 96% of the compounds) and the accuracy (80–120% for 88% of the compounds) were satisfactory. Evaluation of the CCβ values and the linearity results demonstrates that the developed method shows adequate sensitivity and linearity to provide quantitative results. Furthermore, the method is accurate enough to differentiate between suspected and negative samples or drug concentrations below or above the MRL. A set of 100 samples of raw milk were screened for residues. No suspected (positive) results were obtained except for the included blind reference sample containing sulphamethazine (88 μg/l) that tested positive for this compound. UPLC–ToF-MS combines high resolution for both LC and MS with high mass accuracy which is very powerful for the multi-compound analysis of veterinary drugs. The technique seems to be powerful enough for the analysis of not only veterinary drugs but also organic contaminants like pesticides, mycotoxins and plant toxins in one single method.  相似文献   

8.
Systematic toxicological analysis (STA) is aimed at detecting and identifying all substances of toxicological relevance (i.e. drugs, drugs of abuse, poisons and/or their metabolites) in biological material. Particularly, gas chromatography–mass spectrometry (GC/MS) represents a competent and commonly applied screening and confirmation tool. Herein, we present an untargeted liquid chromatography–tandem mass spectrometry (LC/MS/MS) assay aimed to complement existing GC/MS screening for the detection and identification of drugs in blood, plasma and urine samples. Solid-phase extraction was accomplished on mixed-mode cartridges. LC was based on gradient elution in a miniaturized C18 column. High resolution electrospray ionization-MS/MS in positive ion mode with data-dependent acquisition control was used to generate tandem mass spectral information that enabled compound identification via automated library search in the “Wiley Registry of Tandem Mass Spectral Data, MSforID”. Fitness of the developed LC/MS/MS method for application in STA in terms of selectivity, detection capability and reliability of identification (sensitivity/specificity) was demonstrated with blank samples, certified reference materials, proficiency test samples, and authentic casework samples.  相似文献   

9.
A qualitative method, involving supported liquid–liquid extraction (SLE) and ultra high pressure liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS–MS), was developed for the rapid tentative identification of various drugs of abuse in urine. In this study, 28 drugs and metabolites were covered by the screening procedure. Before analysis, urine samples were extracted by SLE and good extraction recoveries were obtained for most investigated compounds. The UHPLC strategy was then selected for the rapid separation of amphetamines, cocaine, opiates and related compounds in urine. Using columns packed with sub-2 µm particles, analysis time was reduced down to 2 min, while maintaining acceptable performance. Finally, the detection was by tandem MS operating in the single reaction monitoring (SRM) mode. The most intense transition was selected for the different drugs and SRM dwell times set at 5 ms, to maintain sufficient data points across the narrow UHPLC peaks. The tentative identification of the drugs of interest, including amphetamines, opiates and cocaine, was based on both, retention times and mass spectrometry information. With the proposed method, limits of detection were estimated at about 1 ng mL?1 and the applicability was assessed by successfully analyzing several samples of drug abusers. Finally, this study demonstrates the potential of UHPLC coupled to tandem MS for the rapid screening of drugs of abuse in urine.  相似文献   

10.
A liquid chromatographic/tandem mass spectrometric (LC/MS/MS) multiresidue method for the simultaneous quantitative determination of oxytetracycline, 4-epi-oxytetracycline, tetracycline, 4-epi-tetracycline, chlortetracycline, 4-epi-chlortetracycline and doxycycline in milk has been developed. An extraction procedure consisting of a liquid extraction of the milk samples with trichloroacetic acid was performed. The extract was centrifuged and the supernatant was filtered. Solid-phase extraction (SPE) with an OASIS HLB SPE column was used to clean up the sample extracts. The samples were analysed by LC/MS/MS. The LC separation was performed on a reversed-phase C18 column using gradient elution with a mobile phase consisting of water and a mixture of methanol/acetonitrile. The tetracycline analytes were detected with a quadrupole mass spectrometer using positive ion electrospray ionisation. The confirmatory method has acceptable detection limits and the different tetracyclines can be detected at a residue concentration between 5 and 20 microg/L. The method is validated according to the European requirements for veterinary drug residues and all determined parameters were found to conform to the criteria. The recovery values ranged from 90.4 to 101.2% with relative standard deviations (RSDs) no larger than 9.7%. The overall or between-day precision of the analytical assay determined as repeatability at several residue concentrations and expressed as RSD ranged from 3.3 to 10%. This analytical assay is a useful tool within the Belgian monitoring programme for confirmation of samples which have been positively screened for residues of tetracyclines in raw farm cow's milk.  相似文献   

11.
LC coupled to single (LC–MS) and tandem (LC–MS/MS) mass spectrometry is recognized as the most powerful analytical tools for metabolic studies in drug discovery. In this article, we describe five cases illustrating the utility of screening xenobiotic metabolites in routine analysis of forensic samples using LC–MS/MS. Analyses were performed using a previously published LC–MS/MS general unknown screening (GUS) procedure developed using a hybrid linear IT–tandem mass spectrometer. In each of the cases presented, the presence of metabolites of xenobiotics was suspected after analyzing urine samples. In two cases, the parent drug was also detected and the metabolites were merely useful to confirm drug intake, but in three other cases, metabolite detection was of actual forensic interest. The presented results indicate that: (i) the GUS procedure developed is useful to detect a large variety of drug metabolites, which would have been hardly detected using targeted methods in the context of clinical or forensic toxicology; (ii) metabolite structure can generally be inferred from their “enhanced” product ion scan spectra; and (iii) structure confirmation can be achieved through in vitro metabolic experiments or through the analysis of urine samples from individuals taking the parent drug.  相似文献   

12.
A fast screening method is presented for detecting isopropylthioxanthone (ITX) contamination in milk. The method is based on direct high-performance liquid chromatography/tandem mass spectrometry (HPLC/MS/MS) analysis of milk samples. Sample preparation is limited to the addition of a deuterated ITX solution in acetonitrile that serves both as internal standard and to precipitate proteins. The method is highly accurate and sensitive. Isomeric specific analyses of 2-ITX and 4-ITX are possible at 6 microg/L levels with about 5% precision and accuracy. This approach has been used to check contamination in samples like milk, soy milk, baby milk, in their packaging material. Out of 37 milk samples analyzed, 16 were positive with concentrations ranging from 173-439 microg/L for 2-ITX and from <6 (lower than limit of quantification) to 25 microg/L for 4-ITX.  相似文献   

13.
A liquid chromatographic (LC) multiresidue screening procedure was developed for determination of eprinomectin, moxidectin, abamectin, doramectin, and ivermectin in beef liver at 0, 25, 50, and 100 ppb levels. A procedure using low resolution LC/atmospheric pressure chemical ionization (APCI) mass spectrometry (MS) was developed with further purification steps added to the quantitative LC method to confirm residues. Acetonitrile extracts of liver, prior to derivatization for LC analysis, were further purified by using a C8 solid-phase extraction cartridge and an alumina-B cartridge. The purified extract was analyzed by injection into an LC/positive ion APCI MS. Identity of the compound was confirmed by comparison of its retention time and relative intensity data with those of a standard or recovery from a fortified control liver sample. Anthelmintic drugs in acetonitrile extracts of liver containing eprinomectin, moxidectin, abamectin, doramectin, and ivermectin at 25 ppb, the lowest level of fortification used in the LC determinative method, were successfully confirmed.  相似文献   

14.
In drug discovery today, drug exposure is determined in preclinical efficacy and safety studies and drug effects are related to measured concentrations rather than to the administered dose. This leads to a strong increase in the number of bioanalytical samples, demanding the development of higher throughput methods to cope with the increased workload. Here, a combined approach is described for the high-throughput preparation and liquid chromatography/tandem mass spectrometry (LC/MS/MS) analysis of drug levels in plasma samples from the preclinical efficacy and safety studies, i.e. exposure studies. Appropriate pharmacokinetic (PK) compartmental models were fitted to data from PK screening studies in the rat, which were subsequently used to simulate the expected plasma concentrations of the respective exposure studies. Information on the estimated drug concentrations was used to dilute the samples to appropriate concentration levels. A Tecan Genesis RSP liquid handling system was utilized to perform automated plasma sample preparation including serial dilution of standard solutions, dilution of plasma samples, addition of internal standard solution and precipitation with acetonitrile. This robotic sample preparation process permitted two studies of 1-96 samples each to be run simultaneously. To ensure the performance of this method the accuracy and precision for diazepam were examined. Two novel drugs were used to illustrate the suggested approach. In conclusion, our method for sample preparation of exposure samples, based on the combined use of PK simulations, a liquid handling system and a fast LC/MS/MS method, increased the throughput more than three times and minimized the errors, while maintaining the required accuracy and precision.  相似文献   

15.
A rapid and simple sample preparation procedure for determining residues of antibiotics of the class of macrolides and lincomycin in whole milk and yoghurt by liquid chromatography/tandem mass spectrometry (LC/MS/MS) is presented. The method is based on the matrix solid-phase dispersion (MSPD) technique with hot water as extractant. After dispersing samples of milk and yoghurt on sand, target compounds were eluted from the MSPD column by passing through it 5 mL of water acidified with 30 mmol/L formic acid and heated at 70 degrees C. After pH adjustment and filtration, a volume of 200 microL of the aqueous extract was directly injected into the LC column. MS data acquisition was generally performed in the multiple reaction monitoring (MRM) mode, selecting two precursor ion to product ion transitions for each target compound. Hot water appeared to be an efficient extracting medium, since absolute recoveries of the analytes in milk and yoghurt were respectively 68-86% and 82-96%. The method proved to be robust as matrix effects, even though present, did not affect significantly the accuracy of the method, as evidenced by analyzing six different batches of both milk and yoghurt. Using roxithromycin (a macrolide antibiotic not used in veterinary medicine) as surrogate internal standard, the accuracy of the method at three different spike levels of the analytes in milk and yoghurt was 86-107% (RSDs not larger than 10%) and 97-117% (RSDs not larger than 13%), respectively. On the basis of a signal-to-noise ratio of 10, we estimated this method can quantify a few ppb of the analytes in milk and yoghurt. These concentrations are well below the tolerance levels of macrolides and lincomycin in milk set by both the European Union and the US Food and Drug Administration. On analyzing six yoghurt samples, we found evidence for the fact that one of the six samples was contaminated with erythromycin B.  相似文献   

16.
There is a continuing need for increased throughput in the evaluation of new drug entities in terms of their pharmacokinetic (PK) parameters. This report describes an alternative procedure for increasing the throughput of plasma samples assayed in one overnight analysis: the use of parallel high performance liquid chromatography (HPLC) combined with tandem mass spectrometry (parallel LC/MS/MS). For this work, two HPLC systems were linked so that their combined effluent flowed into one tandem MS system. The parallel HPLC/APCI-MS/MS system consisted of two Waters 2690 Alliance systems (each one included an HPLC pump and an autosampler) and one Finnigan TSQ 7000 triple quadrupole mass spectrometer. Therefore, the simultaneous chromatographic separation of the plasma samples was carried out in parallel on two HPLC systems. The MS data system was able to deconvolute the data to calculate the results for the samples. Using this system, 20 compounds were tested in one overnight assay using the rapid rat PK screening model which includes a total of 10 standards plus samples and two solvent blanks per compound tested. This application provides an additional means of increasing throughput in the drug discovery PK assay arena; using this approach a two-fold increase in throughput can be achieved in the assay part of the drug discovery rat PK screening step.  相似文献   

17.
建立了固相萃取-超高效液相色谱-串联质谱(SPE-UPLC-MS/MS)同时检测鸡蛋、液态奶、鸡肉及淡水鱼中4类(氯霉素类、硝基咪唑类、林可酰胺类与大环内酯类)8种禁限兽药与3种代谢物残留的分析方法.对样品前处理及色谱条件进行优化,样品经0.1 mol/L pH 9.0的磷酸盐缓冲液水解分散,乙腈提取,提取液经乙酸乙酯...  相似文献   

18.
In Japan, not only the classical stimulant, methamphetamine, but also a wide variety of illicit drugs and designer drugs are abused by juveniles. It is, however, difficult to screen these drugs in human urine due to the poor availability of high-quality standards. Therefore, it is important to develop a screening method that does not require the use of standard compounds. Furthermore, if we can obtain approximate drug concentrations in biological fluids by the first screening procedure, the subsequent treatment of the patient and forensic diagnosis can be carried out more rapidly and exact quantitative analysis performed more efficiently. We have devised a rapid screening method for the simultaneous semi-quantitative analysis of 30 abused drugs using gas chromatography/mass spectrometry (GC/MS) with a retention time locking technique. Based on this method, an 'abused drugs database' was constructed including retention time (RT), qualifier ion/target ion (QT) percentage and calibration curve (values of slope and intercept) using the novel GC/MS software, NAGINATA. We compared the analytical results obtained by this method using the constructed database with those from conventional methods in six forensic cases. The number of confirmed drugs and concentrations obtained by the established method was comparable with that obtained by conventional methods. We found a significant improvement in the time for data analysis, and qualitative and quantitative information about each drug was obtained without using standards. Therefore, this new screening procedure using NAGINATA has potential for the rapid identification of poisoning and should be useful in clinical and forensic toxicological analyses.  相似文献   

19.
Forensic investigations involving acute or lethal intoxication, drug-facilitated sexual assault, driving or workplace impairment frequently require the analysis of fresh or postmortem blood samples to check out a wide variety of pharmaceutical and illicit drugs, even after single-dose consumption. A sensitive and selective ultrahigh-performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS) screening method was developed for fast screening of 88 psychoactive drugs and metabolites in blood samples, including the ones most frequently involved in acute intoxications and forensic investigations in Italy. The new method allows short sample processing and analysis time (the whole procedure can be accomplished in less than 30 min) together with the simultaneous monitoring of a large number of pharmaceutical substances. These features represent crucial factors in the approach of acute intoxications, when the patient requires urgent and appropriate therapy. Blood sample treatment was limited to protein precipitation. Two UHPLC–MS/MS runs in positive and negative electrospray ionization modes were performed. The data were acquired at unit mass resolution in the selected reaction monitoring mode. According to international guidelines, linearity range, precision, trueness, detection and quantification limits, recovery, selectivity, specificity, carryover, and matrix effect phenomena were determined. Despite the limited sample purification and the inherent decreased chance of eliminating any potential interference, the present multiresidue screening method proved extremely effective and sensitive, allowing the detection of all tested drugs, even those belonging to structurally different classes of substances. Moreover, the developed method is easily susceptible to further expansion to encompass more drugs, either new or those becoming important for criminal investigation. This protocol was also applied to the analysis of authentic blood samples collected from victims of various crimes in routine casework, whose relevance in forensic investigations is presented in five cases.  相似文献   

20.
LC–high resolution (HR)-MS well established in proteomics has become more and more important in bioanalysis of small molecules over the last few years. Its high selectivity and specificity provide best prerequisites for its use in broad screening approaches. Therefore, Orbitrap technology was tested for developing a general metabolite-based LC–HR-MS/MS screening approach for urinalysis of drugs necessary in clinical and forensic toxicology. After simple urine precipitation, the drugs and their metabolites were separated within 10 min and detected by a Q-Exactive mass spectrometer in full scan with positive/negative switching, and subsequent data dependent acquisition (DDA) mode. Identification criteria were the presence of accurate precursor ions, isotopic patterns, five most intense fragment ions, and comparison with full HR-MS/MS library spectra. The current library contains over 1900 parent drugs and 1200 metabolites. The method was validated for typical drug representatives and metabolites concerning recovery, matrix effects, process efficiency, and limits showed acceptable results. The applicability was tested first for cardiovascular drugs, which should be screened for in poisoning cases and for medication adherence of hypertension patients. The novel LC–HR-MS/MS method allowed fast, simple, and robust urine screening, particularly for cardiovascular drugs showing the usefulness of Orbitrap technology for drug testing.  相似文献   

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