Simultaneous determination of residual polychlorinated biphenyls and organochlorine pesticides in fish and fish products by gas-liquid chromatography

A procedure is developed for the simultaneous determination of polychlorinated biphenyls and organochlorine pesticides in fish and fish products by gas-liquid chromatography with an electron capture detector on a capillary column DB-1701 (30 m × 0.25 mm × 0.25 μm) under temperature-programming conditions. The detection limit is 0.06 μg/kg of the test sample. Polychlorinated biphenyls and organochlorine pesticides were extracted from the samples using a hexane-acetone mixture (1 : 1). Lipids were removed by treatment with H₂SO₄. Eighteen samples were analyzed; the concentrations of pollutants were found to be below the prescribed values.     

Analytical methods for multiresidue determination of sulfonamides and trimethoprim in meat and ground water samples by CE-MS and CE-MS/MS

This paper presents two methods based on CZE-MS detection and CZE-MS/MS detection developed for the multiresidue determination of ten sulfonamides (sulfapyridine, sulfadoxin, sulfamethazine, sulfadimethoxine, sulfameter, sulfamerazine, sulfachlorpyridazine, sulfadiazine, sulfamethoxazole, and sulfamethizole) and a potentiator, trimethoprim (TMP), whose contents are regulated by the EU Council Regulation no. 2377/90 in animal edible tissues. Experimental designs were employed to optimize the electrospray conditions. MS/MS experiments using an IT as analyzer operating in multiple reaction monitoring (MRM) mode were carried out to achieve the minimum number of points according to the 2002/657/EC European Decision for unambiguous identification. The proposed procedures have been compared in terms of the performance characteristics and trueness. The limits of detection and quantification were in all cases lower than the maximum residue limits legislated for these compounds and the recoveries were satisfactory, being possible the application for their monitoring in foodstuff of animal origin and in environmental samples, allowing the determination of sulfonamides and TMP residues in meat and in superficial water in the low microg/L range.     

Simultaneous determination of residual synthetic antibacterials in fish by high-performance liquid chromatography

A simple and rapid high-performance liquid chromatographic (HPLC) method for the simultaneous determination of sulphamonomethoxine (SMMX), sulphadimethoxine (SDMX), sulphisozole (SIZ), nalidixic acid (NA), oxolinic acid (OXA), piromidic acid (PMA), furazolidone (FZ) and sodium nifurstyrenate (NFSA) in cultured fish was developed. The drugs were extracted with 0.2% metaphosphoric acid-methanol (6:4), followed by a Bond Elut C18 clean-up procedure. The HPLC separation was carried out on an Inertsil ODS column (150 x 4.6 mm I.D.) using 5 mM aqueous oxalic acid-acetonitrile (55:45) as the mobile phase with detection at 265 nm (0.04 a.u.f.s.). The calibration graphs were rectilinear from 1 to 20 ng for OXA, from 2 to 50 ng for SMMX, SDMX, SIZ, NA, PMA and FZ and from 5 to 100 ng for NFSA. The recoveries of each drug added to fish were 65.0-89.5%. The detection limits were 0.02 micrograms/g for OXA, 0.05 micrograms/g for SMMX, SDMX, SIZ, NA, PMA and FZ and 0.1 micrograms/g for NFSA.     

Simultaneous determination of pyridoxal and pyridoxamine by different spectrofluorimetric techniques

Binary mixtures of pyridoxal and pyridoxamine can be resolved by using zero-crossing first derivative spectrofluorimetry, first devivative constant wavelength synchronous luminescence spectrometry and first derivative constant energy synchronous luminescence spectrometry. These methods do not require any previous separation steps. The lowest quantization limit is obtained with first derivative constant energy synchronous fluorescence (13.0 and 9.0 mug/1. for pyridoxal and pyridoxamine, respectively). The measurements were performed in aqueous medium at pH 7.0 provided by adding 0.05M phosphate buffer solution. In order to demonstrate the validity of these methods a complete and exhaustive statistical analysis of the experimental data was performed. Pyridoxal and pyridoxamine were determined by these methods in synthetic and real mixtures with good results.     

超高效液相色谱-串联质谱法同时测定土壤中30种抗生素

土壤基质复杂,土壤中残留的抗生素种类繁多,浓度多为痕量水平,高灵敏度的仪器方法、有效的净化和富集方法、多种类抗生素的同时检测是土壤中抗生素检测的重点和难点.该研究建立了固相萃取-超高效液相色谱-串联质谱法同时测定土壤中7类(磺胺类、氟喹诺酮类、四环素类、大环内酯类、β-内酰胺类、酰胺醇类和林可酰胺类)30种抗生素的方法...     

分散固相萃取净化-超高效液相色谱-串联质谱法同时测定鱼和虾中抗生素及三苯甲烷类兽药残留

建立了分散固相萃取净化-超高效液相色谱-串联质谱法快速测定鱼和虾中3类（磺胺类、喹诺酮类、氯霉素类）18种抗生素及2种三苯甲烷类（孔雀石绿、隐色孔雀石绿）兽药残留。样品经磷酸氢二钾溶液水解分散，乙腈提取，提取液经氯化钠脱水、盐析后取乙腈层，经旋转蒸发仪浓缩至近干，残留物用甲醇定容至1.0 mL，C18和PSA（N-丙基乙二胺）填料分散固相萃取净化，过滤膜后经ZORBAX C18色谱柱（50 mm×2.1 mm，1.8 μm）分离，正、负离子多反应监测模式采集数据，同位素内标法定量。实验结果表明，20种兽药在0.2~300 μg/L范围内具有良好的线性关系，检出限为0.1~0.6 μg/kg，定量限为0.3~1.8 μg/kg，相关系数均大于0.99。在1、5和20倍定量限加标浓度水平下，平均回收率为72.5%~118%，相对标准偏差（RSD）为1.9%~9.8%。该方法具有前处理简单、检测效率高、成本低等优点，适用于鱼和虾中多类兽药残留的同时测定。     

Simultaneous screening and confirmation of multiple classes of drug residues in fish by liquid chromatography-ion trap mass spectrometry

LC-ion trap mass spectrometry was used to screen and confirm 38 compounds from a variety of drug classes in four species of fish: trout, salmon, catfish, and tilapia. Samples were extracted with acetonitrile and hexane. The acetonitrile phase was evaporated, redissolved in water and acetonitrile, and analyzed by gradient chromatography on a phenyl column. MS² or MS³ spectra were monitored for each compound. Qualitative method performance was evaluated by the analysis over several days of replicate samples of control fish, fish fortified with a drug mixture at 1 ppm, 0.1 ppm and 0.01 ppm, and fish dosed with a representative from each drug class. Half of the 38 drugs were confirmed at 0.01 ppm, the lowest fortification level. This included all of the quinolones and fluoroquinolones, the macrolides, malachite green, and most of the imidazoles. Florfenicol amine, metronidazole, sulfonamides, tetracyclines, and most of the betalactams were confirmed at 0.1 ppm. Ivermectin and penicillin G were only detectable in the 1 ppm fortified samples. With the exception of amoxicillin, emamectin, metronidazole, and tylosin, residue presence was confirmed in all the dosed fish.     

SPE-UPLC-MS/MS同时测定水环境中4大类15种抗生素EI北大核心CSCD

建立了应用固相萃取-超高效液相色谱-串联质谱技术(SPE-UPLC-MS/MS)同时测定水环境中包括磺胺类、四环素类、大环内酯类和喹诺酮类在内的4大类15种抗生素的方法。采集的水样中加入同位素替代物后通过HLB固相萃取柱进行富集浓缩,UPLC-MS/MS进行测定,并采用内标法定量。结果表明,15种抗生素在0.5~50μg/L线性范围内检出限为0.04~0.09 ng/L,定量限为0.16~0.36 ng/L,样品加标回收率为59.5%~102.8%,相对标准偏差(RSD)均小于12%。该方法适用于水环境中痕量残留的抗生素检测。     

Fast determination of tetracycline antibiotics in different media by high-performance liquid chromatography

Summary The use of high-performance liquid chromatography (HPLC) for the identification and determination of tetracycline antibiotics is reviewed. HPLC chromatograms provide fast identification by retention time, t_R, and precise quantitation by measurement of peak height or peak area. For separation of tetracycline compounds, most HPLC methods use reversed-phase C₁₈ or C₈ columns and UV detection. The HPLC solvent system should have a pH of about 6 to prevent steric changes in the tetracycline molecule. For accurate quantitation it is necessary to avoid tailing and this is accomplished by adding a zwitter ion to the solvent system. Methanol and acetonitrile are frequently used as organic modifiers in these solvent systems. In a single analysis, HPLC methods can be used to separate as many as nine or ten commercially used tetracycline compounds and to determine four to five tetracyclines in commercial tetracycline preparations or in biological fluids.     

高效液相色谱法同时测定祛痘产品中6种抗生素及甲硝唑

建立了一种高效液相色谱-二极管阵列检测器(HPLC-DAD)同时测定祛痘产品中6种抗生素(盐酸美满霉素、土霉素、盐酸四环素、盐酸金霉素、盐酸多西环素和氯霉素)及甲硝唑的分析方法。样品用甲醇提取,采用Agilent ZORBAX SB-C18色谱柱(250 mm×4.6 mm, 5 μm)分离;以甲醇、乙腈和0.002 mol/L草酸为流动相进行梯度洗脱,流速0.8 mL/min;柱温20 ℃,检测波长268 nm,进样量10 μL,外标法定量。结果表明,6种抗生素及甲硝唑在1～30 mg/L范围内呈良好的线性关系,相关系数(r)均不低于0.9970;方法检出限为1.1～1.2 μg/g;高、中、低(5、10、20 mg/L) 3个添加水平下的回收率为91.9%～107.7%,相对标准偏差(RSD)为0.13%～1.74%。应用该方法对祛痘产品进行检验,15%的样品中检出甲硝唑。该方法具有灵敏、准确、快速、分离效果好的优点,适用于祛痘产品中6种抗生素及甲硝唑的检测。     

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.     

Simultaneous determination of 32 antibiotics in aquaculture products using LC-MS/MS

An analytical multiclass, multi-residue method for the determination of antibiotics in aquaculture products was developed and validated. A fast, cheap, and straightforward extraction procedure followed by liquid chromatography-tandem mass spectrometry analysis was proposed. This method covers 32 antibiotics of different classes, which are frequently used in aquaculture. Three different extraction procedures were compared, and the extraction with acetonitrile (0.1 vol. % formic acid) showed the best results. The selected extraction procedure was validated at four different fortification levels (10 μg kg^?1, 25 μg kg^?1, 50 μg kg^?1, and 100 μg kg^?1). Recoveries of the tested antibiotics ranged from 70 % to 120 %, with the relative standard deviation (RSD) of triplicates lower than 20 %. The limits of quantification (LOQ) ranged from 0.062 μg kg^?1 to 4.6 μg kg^?1, allowing for the analysis of trace levels of these antibiotics in aquaculture products. The method was applied to the analysis of selected antibiotics in fish and shrimp meat available in the Czech market.     

QuEChERS-超高效液相色谱-串联质谱法同时测定畜禽组织中6种黄曲霉毒素和杂色曲霉素

建立了QuEChERS前处理技术结合超高效液相色谱-串联质谱（UHPLC-MS/MS）检测畜禽组织中6种黄曲霉毒素和杂色曲霉素残留的分析方法。样品经20 μL β-葡萄糖苷酶酶解和10 mL乙腈-水（84：16,v/v）提取,然后用1.0 g氯化钠和1.0 g无水硫酸镁净化、5 mL正己烷脱脂,最后采用1 mL含5 mmol/L乙酸铵的乙腈-水溶液（80：20,v/v）复溶。以甲醇和5 mmol/L乙酸铵为流动相,在多反应监测正离子模式下进行检测,采用基质匹配标准曲线外标法进行定量分析。结果显示,6种黄曲霉毒素和杂色曲霉素在各自的范围内线性关系良好,相关系数（R²）>0.99,检出限（LOD,S/N=3）为0.007~0.30 μg/kg,定量限（LOQ,S/N=10）为0.02~0.91 μg/kg,加标回收率为77.3%~118.5%（n=6）。该法简单、快速,灵敏度高,适用于不同畜禽产品中6种黄曲霉毒素和杂色曲霉素的确证分析。     

Multiresidue determination of quinolone and fluoroquinolone antibiotics in fish and shrimp by liquid chromatography/tandem mass spectrometry

A multiresidue method was developed to measure low levels of 8 fluoroquinolones (norfloxacin, ofloxacin, danofloxacin, ciprofloxacin, desethylene ciprofloxacin, enrofloxacin, sarafloxacin, and difloxacin) and 4 quinolones (oxolinic acid, flumequine, nalidixic acid, and piromidic acid). Method detection limits range from 0.1 ng/g for quinolones to 0.4 ng/g for fluoroquinolones. Average recoveries range from 57 to 96%, depending on analyte and commodity; relative standard deviations are all less than 18%. The drugs are extracted from tissues using a mixture of ethanol and 1% acetic acid, diluted in aqueous HCI, and defatted by extraction with hexane. The compounds are further isolated using cation-exchange solid-phase extraction and measured using liquid chromatography with electrospray tandem mass spectrometry detection. The method has been evaluated and applied to the analysis of salmon, trout, and shrimp. Detectable residues were observed in 10 out of 73 samples, at concentrations ranging from 0.28 to 16 ng/g.     

超高效液相色谱-电喷雾串联质谱法测定动物饲料中的大环内酯类和林可胺类抗生素

建立了动物饲料中竹桃霉素、红霉素、吉他霉素、交沙霉素、罗红霉素、泰乐菌素6种大环内酯和林可霉素、克林霉素2种林可胺抗生素的超高效液相色谱-电喷雾串联质谱(UPLC-ESI-MS/MS)检测方法。饲料样品采用甲醇提取,Oasis HLB固相萃取柱富集净化,Waters Acquity UPLC BEH C18色谱柱分离,以0.1%甲酸和乙腈为流动相进行梯度洗脱,流速为0.3 mL/min,正离子模式扫描,多反应监测模式检测,外标法定量。实验结果表明,8种药物在1～100 μg/L范围内具有良好的线性关系。在空白饲料样品中分别添加1、10和100 μg/kg 3个加标水平的8种药物,其平均回收率为68.6%～95.2%,相对标准偏差(RSD)为4.9%～11.8%,定量限均为1 μg/kg。结果表明,该方法简便快速、灵敏度高,适用于动物饲料中大环内酯类和林可胺类抗生素的同时检测。     

Simultaneous analysis of pesticides from different chemical classes by using a derivatisation step and gas chromatography-mass spectrometry

This work presents a new method to analyse simultaneously by GC–MS 31 pesticides from different chemical classes (2,4 D, 2,4 MCPA, alphacypermethrin, bifenthrin, bromoxynil, buprofezin, carbaryl, carbofuran, clopyralid, cyprodinil, deltamethrin dicamba, dichlobenil, dichlorprop, diflufenican, diuron, fenoxaprop, flazasulfuron, fluroxypyr, ioxynil, isoxaben, mecoprop-P, myclobutanil, oryzalin, oxadiazon, picloram, tau-fluvalinate tebuconazole, triclopyr, trifluralin and trinexapac-p-ethyl). This GC–MS method will be applied to the analysis of passive samplers (Tenax^® tubes and SPME fiber) used for the evaluation of the indoor and outdoor atmospheric contamination by non-agricultural pesticides. The method involves a derivatisation step for thermo-labile or polar pesticides. Different agents were tested and MtBSTFA (N-(t-butyldimethylsilyl)-N-methyltrifluoroacetamide), a sylilation agent producing very specific fragments [M−57], was retained. However, diuron could not be derivatised and the isocyanate product was used for identification and quantification. Pesticides which did not need a derivatisation step were not affected by the presence of the derivatisation agent and they could easily be analysed in mixture with derivatised pesticides. The method can be coupled to a thermal-desorption unit or to SPME extraction for a multiresidue analysis of various pesticides in atmospheric samples.     

Simultaneous determination of 11 antibiotics and their main metabolites from four different groups by reversed-phase high-performance liquid chromatography-diode array-fluorescence (HPLC-DAD-FLD) in human urine samples

A new, accurate and sensitive reversed-phase high-performance liquid chromatography (RP-HPLC) as analytical method for the quantitative determination of 11 antibiotics (drugs) and the main metabolites of five of them present in human urine has been worked out, optimized and validated. The analytes belong to four different groups of antibiotics (sulfonamides, tetracyclines, penicillins and anphenicols). The analyzed compounds were sulfadiazine (SDI) and its N⁴-acetylsulfadiazine (NDI) metabolite, sulfamethazine (SMZ) and its N⁴-acetylsulfamethazine (NMZ), sulfamerazine (SMR) and its N⁴-acetylsulfamerazine (NMR), sulfamethoxazole (SMX), trimetroprim (TMP), amoxicillin (AMX) and its main metabolite amoxicilloic acid (AMA), ampicillin (AMP) and its main metabolite ampicilloic acid (APA), chloramphenicol (CLF), thiamphenicol (TIF), oxytetracycline (OXT) and chlortetracycline (CLT). For HPLC analysis, diode array (DAD) and fluorescence (FLD) detectors were used. The separation of the analyzed compounds was conducted by means of a Phenomenex^® Gemini C₁₈ (150 mm × 4.6 mm I.D., particle size 5 μm) analytical column with LiChroCART^® LiChrospher^® C₁₈ (4 mm × 4 mm, particle size 5 μm) guard column. Analyzed drugs were determined within 34 min using formic acid 0.1% in water and acetonitrile in gradient elution mode as mobile phase. A linear response was observed for all compounds in the range of concentration studied. Two procedures were optimized for sample preparation: a direct treatment with methanol and acetonitrile and a solid phase extraction procedure using Bond Elut^® Plexa™ columns. The method was applied to the determination of the analytes in human urine from volunteers under treatment with different pharmaceutical formulations. This method can be successfully applied to routine determination of all these drugs in human urine samples.     

Simultaneous residue monitoring of four tetracycline antibiotics in fish muscle by in-tube solid-phase microextraction coupled with high-performance liquid chromatography

An on-line simple and rapid method for the simultaneous determination of tetracycline (TC), oxytetracycline (OTC), chlortetracycline (CTC) and doxycycline (DC) residues in fish muscle was developed by coupling in-tube solid-phase microextraction (SPME) to high-performance liquid chromatography (HPLC) with a photodiode array detector. Biocompatible poly (methacrylic acid-ethylene glycol dimethacrylate) monolithic capillary was selected as the extraction medium, and no precipitating protein and removing fat steps were required prior to extraction. In order to optimize the extraction of these compounds, several in-tube SPME parameters were investigated. Simply performed by extracting with 0.01 M EDTA-MacIlvaine buffer solution (pH 4.0) and centrifugation, the sample then could be directly injected into the device for extraction. The limits of detection of tetracycline, oxytetracycline, chlortetracycline and doxycycline were calculated to be 22, 16, 30 and 21 ng/g, respectively. The calibration curves showed linearity in the range of 100-10,000 ng/g with a linear coefficient R² value above 0.9980. Excellent method reproducibility was found by intra- and inter-day precisions, yielding the R.S.D.s less than 4.22% and 5.71%, respectively.     

Simultaneous determination of different antibiotic residues in bovine and in porcine kidneys by solid-phase fluorescence immunoassay

Parallux, a solid-phase fluorescence immunoassay (SPFIA) developed for antibiotic residue detection in milk, was used for analysis of bovine and porcine kidney tissue. Four tetracyclines, 2 broad-spectrum cephalosporins, 3 beta-lactam antibiotics, and cephapirin were detected in one run after minimal sample preparation. This commercially available test system is designed as cartridges, each with a combination of 1-4 tests. One cartridge can be used to detect 4 analytes in the same sample, or 1 or 2 analytes in different samples. The cartridge with the combination tetracyclines-ceftiofur-penicillin-cephapirin was selected because tetracyclines, beta-lactam antibiotics as well as cephalosporins, are registered for oral or parenteral use in bovines and pigs in Europe. The test is qualitative and is recommended only for screening. Tetracycline, oxytetracycline, chlortetracycline, and doxycycline were easily detected at 300 ppb with the tetracyclines channel; ceftiofur at 1000 ppb and cefquinome at 200 ppb with the ceftiofur channel; penicillin G, ampicillin, and amoxicillin at 50 ppb with the penicillin channel; and cephapirin at 100 ppb with the cephapirin channel. These levels are equal to or lower than the corresponding maximal residue limits in kidney tissue. Cephalexin was not detected. The SPFIA test can be used as an alternative to classical inhibition tests and for post-screening inhibitor- positive kidneys, because it detects 3 specific groups of antibiotics, which enables selection of specific confirmatory methods for identification and quantification.     

Simultaneous determination of four different antibiotic residues in honey by chemiluminescence multianalyte chip immunoassays

We are presenting the first method for identification and quantification of antibiotic derivatives in honey samples using regenerable antigen microarrays in combination with an automated flow injection system. The scheme is based on an indirect competitive immunoassay format using monoclonal antibodies bound to the surface of the microarray. The surface of glass slides was coated with epoxy-activated poly(ethylene glycol) and enables direct immobilization of the antibiotic derivatives. The antigen/antibody interaction on the surface of the chip can be detected by chemiluminescence (CL) read-out via CCD camera. The method allows for fast analysis of the four analytes simultaneously and without purification or extraction. An effective data evaluation method also was developed to warrant unambiguous identification of the spots and to establish grey levels of CL intensities. The software developed enables fast and automated processing of the CL images. Dose?Cresponse curves were obtained for the derivatives of enrofloxacin, sulfadiazine, sulfamethazine and streptomycin. Spiking experiments revealed adequate recoveries within the dynamic ranges of the calibration curves of enrofloxacin (92%?±?6%), sulfamethazine (130%?±?21%), sulfadiazine (89%?±?20%) and streptomycin (93%?±?4%).