Simultaneous determination of tetracylines and quinolones antibiotics in egg by ultra-performance liquid chromatography-electrospray tandem mass spectrometry

We report here an ultra-performance liquid chromatography coupled with tandem mass spectrometric (MS/MS) method for the simultaneous quantitation of multiclass veterinary drugs in egg. The analysis of the target compounds, including 7 tetracyclines and 4 types of quinolones, may be accomplished in 15 min of total run time. The egg was extracted with ethylenediaminetetraacetic acid-Mcllvaine buffer solution and further purified using a polymer-based Oasis HLB solid-phase extraction cartridge. A C18 column was used to separate the analytes followed by MS/MS using an electrospray ion source. The overall average recoveries of the analytes based on matrix-fortified calibration ranged from 71 to 112% with acceptable relative standard deviations of <20% for 6 trials. For all of the target compounds, the limits of quantitation ranged between 0.02 and 4.29 microg/kg. The proposed method is sufficiently sensitive and highly selective.     

Ultra-performance liquid chromatography/tandem mass spectrometry for the simultaneous analysis of aflatoxins B1, G1, B2, G2 and ochratoxin A in beer

The simultaneous analysis of aflatoxins B1, G1, B2, G2 and ochratoxin A in beer was carried out by ultra-performance liquid chromatography/tandem mass spectrometry (UPLC/MS/MS). Mycotoxins were extracted, purified and concentrated from the beer sample in one step using a solid-phase extraction (SPE) cartridge that contained a polymeric sorbent. Optimization of different parameters, such as type of SPE sorbent, type and amount of wash solvent and pH of the sample, was carried out. The mobile phase consisted of a gradient of methanol + water (0.1% HCOOH) and a reversed-phase C18 column was used for the separation. The mass spectrometer used an electrospray ionization source operated in the positive mode to detect aflatoxins and in the negative mode to detect ochratoxin. UPLC/MS/MS is a rapid and sensitive technique that allows the separation of the five toxins in only 3.2 min. The limit of detection is 1 pg.     

多壁碳纳米管净化/超高效液相色谱串联质谱同时测定动物组织中四环素与喹诺酮多残留

采用超高效液相色谱-串联质谱(UPLC-MS/MS)在正离子模式下通过多反应监测(MRM)方式同时测定了猪肉和鸡肉中3种四环素和2种喹诺酮类药物的残留量.残留药物经Mcllvaine-Na2EDTA缓冲溶液(pH4.0)提取后,采用多壁碳纳米管(WMCNTs)固相萃取柱净化,甲酸-乙腈(体积比5:95)洗脱,UPLC-...     

Determination of tetracycline antibiotics in cow's milk by liquid chromatography/tandem mass spectrometry

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.     

Validation of a method for the determination of chloramphenicol in poultry and swine liver by ultra-performance liquid chromatography coupled with tandem mass spectrometry

A sensitive and reliable method has been developed and validated for the determination of chloramphenicol in poultry and swine liver using SPE and ultra-performance liquid chromatography (UPLC)/MS/MS. The liver samples were extracted with ethyl acetate, defatted with n-hexane, and further cleaned up using SPE cartridges with polymeric sorbent. An Acquity BEH C18 column was used for gradient UPLC separation, with water and acetonitrile as the mobile phase. The multiple reaction monitoring mode was used for two precursor-product ion transitions for chloramphenicol and one for the internal standard. The method was validated at 0.1, 0.3, and 1.0 microg/kg. Mean recoveries from fortified samples ranged from 95.5 to 106.7% with an RSD of 12.2%. The method LOD was < 0.02 microg/kg.     

Development of analytical methods for multiresidue determination of quinolones in pig muscle samples by liquid chromatography with ultraviolet detection, liquid chromatography-mass spectrometry and liquid chromatography-tandem mass spectrometry

This paper presents a comparison between liquid chromatography with ultraviolet detection (LC-UV), liquid chromatography-mass spectrometry (LC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods developed for the multiresidue determination of 8 quinolones, around their maximum residue levels (MRLs) in pig muscle. The procedure involves common extraction of the quinolones from the tissues by traditional extraction, a step for clean-up and preconcentration of the analytes by solid-phase extraction (SPE) and a subsequent liquid chromatographic analysis. The methods present satisfactory results of linearity, precision and limits of quantification much lower than the MRLs established by the European Union for quinolones in pig tissues.     

Comparison of several extraction techniques for multiclass analysis of veterinary drugs in eggs using ultra-high pressure liquid chromatography-tandem mass spectrometry

This study compared four extraction methods for the simultaneous determination of tetracyclines, macrolides, quinolones, sulphonamides and anthelmintics (including benzimidazoles and avermectins) in eggs by ultra-high pressure liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). Solvent extraction, solid-phase extraction (SPE), matrix solid-phase dispersion (MSPD) and modified QuEChERS procedure were compared in terms of recovery and number of veterinary drugs extracted. The solvent extraction procedure with a clean-up step provided better results than the other tested procedures. The QuEChERS procedure was simpler and faster, but extracted fewer compounds than solvent extraction. MSPD did not extract tetracyclines and quinolones, whereas macrolides and tetracyclines were not extracted when SPE was applied. The solvent extraction procedure was validated, obtaining recoveries ranging from 60% (sulfaquinoxaline) to 119% (levamisole) with repeatability values (expressed as relative standard deviations, RSDs) lower than 20% at two concentration levels (10 and 100 μg kg⁻¹), except for erythromycin, emamectin and ivermectin that showed RSD values close to 25% at 10 μg kg⁻¹. Limits of quantification (LOQs) were always equal or lower than 5 μg kg⁻¹. Finally the method was applied to egg samples, and erythromycin, enrofloxacin, difloxacin, thiabendazole, emamectin and fenbendazole were detected in four samples.     

High‐throughput 96‐well solid‐phase extraction for preparation of tetracycline followed by liquid chromatography and mass spectrometry analysis

Tetracyclines abuse has frequently occurred in aquaculture against bacteria, rickettsiae, spirochetes, and mycoplasmas. In this study, a high‐throughput sample preparation method was developed using 96‐well plate solid‐phase extraction (p‐SPE) and the extract was analyzed by ultra‐performance liquid chromatography tandem mass spectrometry (UPLC‐MS/MS). The experimental conditions were optimized such that the pH is 4, the eluting solvent is methanol (2 mL), and the sorbent is hydrophilic‐lipophilic balance (HLB) microsphere. The whole protocol was validated, and it showed that the tetracyclines were linear with correlation coefficients ≥ 0.9990, precision and accuracy (RSD%) in 3.9–6.1%, and mean recoveries of 88.6–103.6%. To exhibit the potential of 96‐well p‐SPE as a routine tool for inspection and quarantine, fresh aquatic samples were tested, and among which positive samples were observed. This method was demonstrated to be promising for the purification and enrichment of tetracyclines with reduced time and labor, and indeed practically and particularly suitable for widespread tetracyclines analysis.     

Optimization of antibiotic analysis in water by solid-phase extraction and high performance liquid chromatography–mass spectrometry/mass spectrometry

This paper describes the development of an optimized method based on solid-phase extraction (SPE) followed by liquid chromatography–electrospray ionization tandem mass spectrometry (LC–MS/MS) for the simultaneous analysis of ten antibiotic compounds including tetracyclines, sulfonamides, macrolides and quinolones. LC–MS/MS sensitivity has been optimized by alterations to both LC and MS operations. Of the two high resolution columns tested, Waters Symmetry C₁₈ endcapped and Agilent Zorbax Bonus-RP, the latter was found to show better performance in producing sharp peaks and clear separation for most of the target compounds. Optimization of the MS fragmentation collision and cone energy enhanced the peak areas of the target analytes. The recovery of the target compounds from water samples was most efficient on Waters Oasis HLB SPE cartridge, while methanol was shown to be the most suitable solvent for desorbing the compounds from SPE. In addition, acidification of samples prior to SPE was shown to enhance the recovery of the compounds. To ensure a satisfactory recovery, the flow rate through SPE should be maintained at ≤10 mL min⁻¹. The method was successfully applied to the analysis of antibiotics from environmental water samples, with concentrations being <LOD in tap water, between <LOD to 28 ng L⁻¹ in river water and between <LOD to 230 ng L⁻¹ in sewage effluent.     

固相萃取-高效液相色谱-串联质谱法测定畜禽粪便中的残留抗生素

建立了固相萃取-高效液相色谱-串联质谱法(HPLC-MS/MS)同时测定畜禽粪便中四环素类化合物(四环素、金霉素、土霉素)、喹诺酮类化合物(诺氟沙星、环丙沙星、洛美沙星)和磺胺二甲嘧啶7种抗生素的检测方法。样品中的抗生素用含有甲醇、乙酸和水(6:3:1, 体积比)的混合溶液提取后,经HLB固相萃取小柱纯化富集,采用Symmetry C₁₈色谱柱分离,0.3%甲酸水溶液和0.3%甲酸乙腈溶液作为流动相进行梯度洗脱,电喷雾正离子(ESI⁺)模式电离,多反应监测(MRM)模式检测,外标法定量。结果表明,四环素类化合物和喹诺酮类化合物在50~1000 μg/L、磺胺二甲嘧啶在5~100 μg/L的范围内具有良好线性。3倍信噪比下,四环素类化合物、喹诺酮类化合物和磺胺二甲嘧啶的检出限分别为0.25~7.18、0.15~3.16和0.04 μg/kg。在猪粪和鸡粪样品中添加0.1~10 μg/g水平的四环素类化合物、喹诺酮类化合物和磺胺二甲嘧啶,其平均添加回收率为40%~124%,相对标准偏差(RSD)为3.0%~9.5%。采用该方法对部分养殖场的猪粪和鸡粪进行了检测,结果表明,四环素类化合物均有不同程度的检出,喹诺酮类化合物和磺胺二甲嘧啶有部分检出。该方法具有灵敏度和准确度高的特点,可满足畜禽粪便中四环素类化合物、喹诺酮类化合物及磺胺二甲嘧啶的检测。     

Solid-phase extraction coupled with liquid chromatography-tandem mass spectrometry for determination of trace rosiglitazone in urine

This project evaluated solid-phase extraction (SPE) combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) to determine the trace amount of rosiglitazone in human urine. The analytical performance of four modes of LC-MS and tandem MS operation (atmospheric pressure chemical ionization (APCI), electrospray ionization (ESI), positive and negative ionization) was compared for two mass spectrometers, a triple-quadrupole and a quadrupole ion trap instrument. Rosiglitazone was extracted from urine using a SPE cartridge of 50mg C8 sorbent and acetonitrile used as the eluting solvent. Samples were then separated on a RP18 column interfaced with a tandem mass spectrometer. The recovery of rosiglitazone was greater than 91.2%. The urine assay combining SPE and LC-APCI-MS/MS of triple-quadrupole was proved a very selective and sensitive method for determination of trace rosiglitazone. The assay was linear over a wide range, with a lower limit of quantification of 0.1 ng/mL using 1 mL of urine. The intra- and inter-day precisions were <9.8% and <7.9%, respectively, and the accuracies were in the range 91.0-103.6%. The rosiglitazone concentration profile in human urine was also determined. The results of this study reveal the adequacy of SPE-LC-APCI-MS/MS method for analyzing rosiglitazone from diabetic patients' urines. The concentrations of rosiglitazone were detected to range from 760 to 164 pg/mL.     

Comparison of Different Cartridges of Solid Phase Extraction for Determination of Polyphenols in Tobacco by UPLC/MS/MS and Multivariate Analysis

The comparison of solid phase extraction(SPE) for the preconcentration and isolation of polyphenols in tobacco samples was carried out by ultra-high performance liquid chromatography/tandem mass spectrometry (UPLC/MS/MS) and multivariate analysis.Several adsorbing materials of SPE(C18,NH2,SAX and OASIS) were investigated.It was found that the C18 and OASIS cartridges can not only speed up the purification process,but also simplify the SPE operation.A UPLC/MS/MS was used for the determination of polyphenols ...     

Sample preparation for determination of macrocyclic lactone mycotoxins in fish tissue, based on on-line matrix solid-phase dispersion and solid-phase extraction cleanup followed by liquid chromatography/tandem mass spectrometry

A new method based on matrix solid-phase dispersion (MSPD) on-line with a solid-phase extraction (SPE) cleanup process followed by liquid chromatography with tandem mass spectrometry (LC/MS/MS) is presented for the determination of 3 macrocyclic lactone mycotoxins in fish tissues: zearalenone, alpha-zearalenol, and beta-zearalenol. The sample was prepared in a device that used a reversed-phase material (C18) or a normal-phase material (neutral alumina) as a matrix dispersing agent, and a graphitized carbon black cartridge was used for sequential cleanup by SPE. LC/MS/MS was used for selective determination. Isocratic elution with acetonitrile-methanol-water was used for LC separation; for MS/MS, 2 types of interfaces (a pneumatically assisted electrospray ionization interface or an atmospheric pressure chemical ionization interface) were evaluated and compared in terms of the intensity of the total ion current produced by each analyte. The use of highly selective MSPD on-line with SPE for sample preparation before analysis allowed the removal of interfering matrix compounds present in tissue extracts that would otherwise cause severe ionization suppression of zearalenone and its metabolites during the ionization process. Average recoveries at 100 ng/g were between 83 and 103% with C18 and > or = 67% with neutral alumina; the relative standard deviations were < 11% with C18 and < 18% with alumina. The limits of detection ranged from 0.1 to 1.0 ng/g. Sample preparation is simple to perform, no special technical equipment is required, and solvent volumes are minimal.     

亲水作用色谱-串联四极杆质谱测定液态奶中舒巴坦

建立了亲水作用色谱-串联四极杆质谱测定液态奶中微量舒巴坦的分析方法。样品经0.2%乙酸水溶液提取,HLB固相萃取柱净化、富集,以甲酸铵-乙腈为流动相,经Acquity UPLC BEH HILIC色谱柱分离后采用电喷雾质谱多反应监测方式(MRM)扫描,外标法定量。结果表明,舒巴坦的质量浓度在1～100μg/L范围内线性关系良好,r2大于0.99,定量下限为1.0μg/kg。加标水平在1.0～50.0μg/kg范围时,回收率为82%～102%,相对标准偏差(RSD)为1.6%～4.7%。该方法前处理简便快捷、灵敏度高、回收率和重现性良好,适用于液态奶中舒巴坦的测定。     

Multi-class determination of antimicrobials in meat by pressurized liquid extraction and liquid chromatography-tandem mass spectrometry

A multi-residue method using pressurized liquid extraction (PLE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been developed for determining trace levels of 31 antimicrobials, including beta-lactams, lincosamides, macrolides, quinolones, sulfonamides, tetracyclines, nitroimidazoles and trimethoprim. The extraction method required pre-homogeneization of the meat with EDTA-washed sand and subsequent one-static-cycle extraction for 10 min with 40 ml of water at 1500 psi and 70 degrees C. The effect of operation temperature, pressure, flush volume, and static cycles on PLE performance was studied. Average recoveries ranged from 75 to 99% with relative standard deviations <18%. The method was validated according to the European Union requirements (2002/657/EC). In addition to the quality parameters included in that decision, the limits of detection (LODs) and quantification (LOQs) were determined. The use of LC-MS/MS provided LODs (between 3 and 15 microg kg(-1)) and LOQs (between 10 and 50 microg kg(-1)), by far lower than half of their maximum residue limits (MRLs) (between 50 and 1200 microg kg(-1)). Confirmation of the presence of any of the studied compounds was accomplished in 1h after sample receipt. This methodology has been successfully applied to the analysis of cattle and pig tissue samples from local markets and slaughterhouses of the Valencian Community (Spain). The results showed the presence of some antimicrobials at different concentrations. Quinolones and tetracyclines were the antimicrobials most detected in cattle and pig samples, respectively. Sulfonamides were also frequently detected in both types of samples.     

Multiwalled carbon nanotubes as a solid-phase extraction adsorbent for the determination of three barbiturates in pork by ion trap gas chromatography-tandem mass spectrometry (GC/MS/MS) following microwave assisted derivatization

A new method was developed for the rapid screening and confirmation analysis of barbital, amobarbital and phenobarbital residues in pork by gas chromatography-tandem mass spectrometry (GC/MS/MS) with ion trap MSD. The residual barbiturates in pork were extracted by ultrasonic extraction, cleaned up on a multiwalled carbon nanotubes (MWCNTs) packed solid phase extraction (SPE) cartridge and applied acetone-ethyl acetate (3:7, v/v) mixture as eluting solvent and derivatized with CH3I under microwave irradiation. The methylated barbiturates were separated on a TR-5MS capillary column and detected with an ion trap mass detector. Electron impact ion source (EI) operating MS/MS mode was adopted for identification and external standard method was employed for quantification. One precursor ion m/z 169 was selected for analysis of barbital and amobarbital and m/z 232 was selected for phenobarbital. The product ions were obtained under 1.0 V excitation voltage. Good linearities (linear coefficient R > 0.99) were obtained at the range of 0.5-50 microg kg(-1). Limit of detection (LOD) of barbital was 0.2 microg kg(-1) and that of amobarbital and phenobarbital were both 0.1 microg kg(-1) (S/N > or = 3). Limit of quantification (LOQ) was 0.5 microg kg(-1) for three barbiturates (S/N > or = 10). Satisfying recoveries ranging from 75% to 96% of the three barbiturates spiked in pork were obtained, with relative standard deviations (R.S.D.) in the range of 2.1-7.8%.     

Application of ion-exchange cartridge clean-up in food analysis. VI. Determination of six penicillins in bovine tissues by liquid chromatography-electrospray ionization tandem mass spectrometry

A multiresidue analytical method was developed for the quantification of benzylpenicillin (PCG), phenoxymethylpenicillin (PCV), oxacillin (MPIPC), cloxacillin (MCIPC), nafcillin (NFPC) and dicloxacillin (MDIPC) in bovine tissues using liquid chromatography- electrospray ionization tandem mass spectrometry (LC-ESI MS/MS) with a multiple reaction monitoring technique. Using the deuterated PCG and NFPC as internal standard was effective for improvement of repeatability and accuracy. We chose [M-H-141]- as a monitor ion of MRM analysis and [M-H]- as a precursor ion for each penicillin. Combination of an ion-exchange cartridge clean-up and ion-pair LC enable us to determine the residual penicillins using the standard curves made from standard solutions without the influence of sample matrix on the MS. The average recoveries of PCG, PCV, MPIPC, MCIPC, NFPC and MDIPC from bovine liver, kidney and muscle at the same concentrations as the tolerance levels of PCG (50 microg/kg) ranged from 77 to 101% with the coefficients of variation ranging from 0.7 to 4.2% (n = 5). The limits of quantification for the six penicillins were 2-10 microg/kg in bovine muscle, liver and kidney (S/N ratio >10).     

一种新型固相萃取柱结合超高效液相色谱-串联质谱法选择性富集测定猪肉中的盐酸克伦特罗

发展了一种测定猪肉中盐酸克伦特罗残留的简便、高效、准确的固相萃取-超高效液相色谱-串联质谱(SPE-UPLC-MS/MS)的方法。将搅碎的猪肉样品用5%(v/v)高氯酸超声提取,再以10000 r/min离心15 min后,上清液用SMCX固相萃取柱进行富集和净化。因SMCX是以硅胶为基质兼有反相/强阳离子交换的混合作用模式,因此可以有效地去除复杂基质干扰,达到目标样品的选择性富集和净化的目的。方法学结果表明,该方法在0.25～50 μg/kg范围内具有良好的线性关系,相关系数r为0.9982; 3个添加水平(1.25、12.5、50 μg/kg)的平均回收率为62.2%～ 72.0%,相对标准偏差(RSDs)为4.2%～ 6.1%;检出限(S/N=3)为0.05 μg/kg。所发展的样品前处理和检测方法简单、快速,可用于瘦肉精类成分的选择性富集和分离检测。     

Simultaneous determination of 16 sulfonamides in honey by liquid chromatography/tandem mass spectrometry

A method is described for the determination of 16 sulfonamides in honey. Samples are dissolved in phosphoric acid solution (pH2), cleaned up with 2 solid-phase extraction (SPE) cartridges, an aromatic sulfonic cation-exchange cartridge and an Oasis HLB SPE cartridge, and analyzed both qualitatively and quantitatively by liquid chromatography/tandem mass spectrometry (LC/MS/MS) under the selected conditions. Without exception, calibration curves were linear (r = > 0.995), when sulfamethizole was between 1.0 and 25.0 microg/kg; sulfacetamide, sulfapyridine, sulfadiazine, sulfachloropyridazine, sulfamethoxazole, sulfamerazine, sulfisoxazole, sulfamonomethoxine, and sulfadoxine were between 2.0 and 50.0 microg/kg; sulfamethoxypyridazine, sulfadimethoxine, and sulfathiazole were between 4.0 and 100.0 microg/kg; sulfamethazine and sulfameter were between 8.0 and 200.0 microg/kg; and sulfaphenazole was between 12.0 and 300.0 microg/kg. Average recoveries at 4 fortification levels in the range of 1.0-300 microg/kg in honey were 70.9-102.5%, and relative standard deviations were 2.02-11.52%. The limits of quantitation for the 16 sulfonamides were between 1.0 and 12.0 microg/kg, with the LC/MS/MS method.     

Simultaneous determination of 20 beta-agonists in pig muscle and liver by high-performance liquid chromatography/tandem mass spectrometry

A method was developed to determine 20 illegal residual beta-agonists in pork tissues, including muscle and liver simultaneously. The samples were hydrolyzed by beta-glucuronidase, purified by PCX SPE cartridges, and detected by HPLC coupled with electrospray ionization MS/MS operating in the positive ion mode. Matrix-fortified calibration was performed to compensate for the matrix effect and loss in sample preparation. Decision limit ranged from 0.05 to 0.23 microg/kg in muscle and 0.05 to 0.57 microg/kg in liver. Decision capacity ranged from 0.11 to 0.4 microg/kg in muscle and 0.16 to 0.79 microg/kg in liver. In Food Analysis Performance Assessment Scheme proficiency test 0287, a pig liver test material containing 13 beta-agonists was analyzed using the method developed, and clenbuterol and ractopamine were confirmed as being present. Z-scores for clenbuterol and ractopamine were 0.2 and 0.6, respectively.