液相色谱-串联质谱法同时测定水产品中孔雀石绿、 结晶紫以及它们的隐色代谢物残留

采用液相色谱-串联质谱法(LC-MS/MS)同时测定水产品中的孔雀石绿、结晶紫以及它们的隐色代谢物残留。匀质后的水产品样品用乙腈和乙酸铵缓冲液提取。合并提取液,用二氯甲烷反提取,经中性氧化铝柱和PRS柱固相萃取净化。采用ZORBAX SB-C18色谱柱,并以0.5 mmol/L乙酸铵-乙腈(体积比为10∶90)混合溶液为流动相,无需使用氧化铅柱在线氧化,色谱分离后直接进入串联质谱检测器检测。采用电喷雾离子源,正离子多反应监测(MRM)模式检测。方法的检测限（S/N=3）可达0.5 ng/g,平均加标回收率为77.6%～98.1%,相对标准偏差均小于8.2%。大量实际水产品样品的检测结果表明,此方法适合于对水产品中孔雀石绿、结晶紫以及它们的隐色代谢物的残留检测。     

超高效液相色谱法同时测定水产品中的盐酸氯苯胍及其代谢产物

建立了水产品肌肉组织中盐酸氯苯胍及其代谢物4-氯苯甲酰胺基乙酸、4-氯苯甲酸和4-氯苯甲醛同时测定的超高效液相色谱双波长分析法。样品经乙酸乙酯(含1%甲酸)提取,无水硫酸钠除水,正己烷除脂后在ACQUIT UPLC BEH C_(18)色谱柱上分离,250 nm和313 nm双波长测定。盐酸氯苯胍及其3种代谢产物在0.05~5.0 mg/L浓度范围内呈良好的线性关系,相关系数(r~2)均≥0.9982。在空白黄颡鱼、中华鳖、罗非鱼和团头鲂组织中进行0.10,0.50,1.0 mg/kg 3个水平的加标回收试验,4种待测物平均回收率为61.7%~104.6%,相对标准偏差为0.97%~9.8%。盐酸氯苯胍、4-氯苯甲酰氨基乙酸和4-氯苯甲酸的检出限(LOD)均为0.025 mg/kg,定量限(LOQ)均为0.05 mg/kg,4-氯苯甲醛的检出限(LOD)为0.05 mg/kg,定量下限(LOQ)为0.10 mg/kg。应用该方法研究了盐酸氯苯胍在团头鲂体内组织分布和消除规律。     

分散固相萃取/液相色谱-串联质谱法测定水产品中的8种青霉素残留

建立了同时测定水产品中8种青霉素(阿莫西林、氨苄西林、青霉素C、青霉素V、苯唑西林、氯唑西林、萘夫西林、双氯西林)残留的液相色谱-串联质谱分析方法.以青霉素G-D7为内标,样品经80％乙腈水溶液提取,c18吸附剂分散固相萃取净化,超滤管过滤后进行分析.采用HyPURITY C18色谱柱,以乙腈(含0.1％甲酸)-0.1...     

高效液相色谱-串联质谱法快速测定水产品中19种喹诺酮类药物残留

应用PRiME HLB净化技术,采用超高效液相色谱-串联四极杆质谱(UPLC-MS/MS),建立了水产品中19种喹诺酮类药物残留的检测方法。对样品的净化、浓缩、液相色谱分离及串联质谱等相关检测参数进行了优化。样品经80%乙腈水溶液提取,PRiME HLB固相萃取柱净化,在ACQUITY BEH C_(18)色谱柱(1.7μm,2.1 mm×100 mm)上以甲醇和5 mmol/L乙酸铵水溶液(含0.1%甲酸)为流动相梯度洗脱,液相色谱-串联质谱MRM方式进行定量分析。结果表明:各组分在各自浓度范围内线性关系良好,平均回收率为72.1%~119.9%,相对标准偏差为2.4%~15.6%,检出限均为0.5μg/kg,定量下限均为1.5μg/kg。该方法用于水产品中喹诺酮类药物残留的检测,具有准确、快速、简便、灵敏度高等优点,为水产品中喹诺酮类药物残留的测定提供了新途径。     

液相色谱-串联质谱法同时检测水产品中苦参碱和鱼藤酮残留

建立了液相色谱-串联质谱同时检测水产品中苦参碱与鱼藤酮残留的方法.试样以乙酸铵缓冲液乙腈提取,提取液中加入 NaCl盐析后,以正己烷除脂净化.采用 Agilent Zobax SB-C<,18>色谱柱,以乙酸铵缓冲液-乙腈为流动相,梯度洗脱分离后,采用电喷雾电离源串联质谱的正离子模式测定.分析物在0.001～0.05m...     

高效液相色谱-荧光法测定水产品中氟苯尼考的残留量

提出了高效液相色谱-荧光法检测水产品中残留的氟苯尼考。以乙酸乙酯为提取溶液,C18固相萃取柱上净化。采用Agilent TC-C18反相色谱柱(250 mm×4.6 mm,5μm)为固相柱,以pH 3.5乙酸盐缓冲溶液和乙腈以体积比55比45混合后作为流动相,在激发波长为225 nm,发射波长为280 nm的条件下进行荧光光度检测。结果表明:氟苯尼考质量浓度在0.1～5.0 mg.L-1范围内与峰面积呈线性关系,检出限(3S/N)为5.6μg.kg-1。方法的回收率为88.6%～95.4%,相对标准偏差(n=6)为3.5%～8.3%。     

高效液相色谱法同时检测水产品中螺旋霉素与泰乐菌素药物残留

建立了同时检测水产品中螺旋霉素与泰乐菌素药物残留的分析方法。在碱性条件下采用乙酸乙酯提取,提取液挥干后溶于酸性缓冲液中,经正己烷去脂、HLB SPE小柱净化后,采用高效液相色谱进行分析。采用Meck Purospher STAR RP18色谱柱(250 mm×4.6 mm,5μm)及乙腈和pH 2.5磷酸缓冲溶液的混合液作梯度淋洗进行分离。分别在232 nm及287 nm对螺旋霉素及泰乐菌素进行紫外检测。方法在1-200 ng之间呈线性相关,相关系数在0.999 8以上,平均回收率为82.2%-89.0%,相对标准偏差为6.24%-9.83%,对螺旋霉素、泰乐菌素的检出限分别为0.005 4 mg.kg-1与0.031 mg.kg-1。     

高效液相色谱-荧光检测法测定水产品中孔雀石绿代谢物残留量

水产品中残留的孔雀石绿经硼氢化钾还原为其代谢物隐色孔雀石绿,采用高效液相色谱对隐色孔雀石绿进行了检测。经均匀化处理的试样用乙腈在pH 4.5的乙酸盐缓冲介质中提取,所得提取液用二氯甲烷液-液分配后,用酸性氧化铝柱进行分离及净化。以Agilent SB-C18色谱柱(250 mm×4.6 mm,5μm)为分离柱,乙腈和乙酸盐缓冲溶液以体积比80比20的混合溶液为流动相,用荧光检测器检测。孔雀石绿的质量浓度在1.0～500.0μg.L-1范围内与其峰面积呈线性关系,检出限(3S/N)为0.46μg.kg-1。方法的回收率在78.0%～95.2%之间,相对标准偏差(n=6)在3.01%～5.98%之间。试验结果表明,孔雀石绿转化为隐色孔雀石绿的转化率在99.1%～100.8%之间。     

QuEChERS/液相色谱-串联质谱法同时测定鱼肉中30种激素类及氯霉素类药物残留

建立了鱼肉中8种雌激素、5种雄激素、6种孕激素、8种糖皮质激素及3种氯霉素类药物多残留的QuEChERS/液相色谱-串联质谱(LC - MS/MS)同时测定方法.均质样品用水分散后加乙腈提取,经分散固相萃取净化后,采用ZORBAX Extend-C18色谱柱(100 mm ×2.1 mm,3.5 μm)分离,分别在电喷...     

液相色谱-串联质谱法快速测定水产品中结晶紫及其隐色代谢物残留

采用液相色谱-串联质谱法(LC-MS/MS)测定了水产品中结晶紫以及它的隐色代谢物残留。匀质后的水产品样品用乙腈和乙酸铵缓冲液提取,合并提取液,用二氯甲烷反提取,经中性氧化铝柱和PRS柱固相萃取净化,且不使用氧化铅柱在线氧化,色谱分离后直接进入串联质谱检测器。采用电喷雾正离子,多反应监测(MRM)模式检测。方法的检出限可达0.5 ng/g,线性方程的相关系数r大于0.99,添加样品平均回收率为77.6%~93.8%,相对标准偏差均小于8.2%。     

Comparison of extraction techniques of robenidine from poultry feed samples

In this paper, effectiveness of six different commonly applied extraction techniques for the determination of robenidine in poultry feed has been compared. The sample preparation techniques included shaking, Soxhlet, Soxtec, ultrasonically assisted extraction, microwave – assisted extraction and accelerated solvent extraction. Comparison of these techniques was done with respect to the recovery extraction, temperature and time, reproducibility and solvent consumption. Every single extract was subjected to clean – up using aluminium oxide column (Pasteur pipette filled with 1 g of aluminium oxide), from which robenidine was eluted with 10 ml of methanol. The eluate from the clean-up column was collected in a volumetric flask, and finally it was analysed by HPLC–DAD–MS. In general, all extraction techniques were capable of isolating of robenidine from poultry feed, but the recovery obtained using modern extraction techniques was higher than that obtained using conventional techniques.

In particular, accelerated solvent extraction was more superior to other techniques, which highlights the advantages of this sample preparation technique. However, in routine analysis, shaking and ultrasonically assisted extraction is still the preferred method for the solution of robenidine and other coccidiostatics.     

高效液相色谱法测定鸡组织与鸡蛋中氯苯胍的残留量

建立了测定鸡组织与鸡蛋中氯苯胍残留的高效液相色谱法。试样用乙腈提取,经HLB固相萃取柱净化和流动相定容后,采用高效液相色谱法测定。以乙腈-0.05 mol/L NH4H2PO4缓冲液(6:4, v/v, pH 6.5)为流动相,流速为1.0 mL/min,于317 nm波长下检测。氯苯胍在10～1000 μg/L范围内具有良好的线性关系;方法的检出限(信噪比为3)为10 μg/L,定量限(信噪比为10)为15 μg/kg;回收率为73.1%～88.7%。该法操作简便、快速、灵敏、准确,样品处理简便易行,适用于测定鸡组织与鸡蛋中残留的氯苯胍。     

Determination of Coccidiostats in Milk Products by LC–MS and Its Application to a Fermentation Experiment

A liquid chromatographic tandem mass spectrometric (LC–MS–MS) method for the determination of five chemical coccidiostats (decoquinate, diclazuril, halofuginone, nicarbazin, and robenidine) and five ionophore coccidiostats (maduramicin, monensin, narasin, salinomycin, and semduramicin) in yoghurt, kefir, and sour cream is presented. Lasalocid, the sixth ionophore listed in 124/2009/EC was not included because of its extremely dissimilar behavior during sample preparation. Main steps of the method include extraction with acetonitrile, centrifugation, clean-up on Oasis HLB solid phase extraction cartridge, evaporation under nitrogen stream, and LC–MS–MS determination. Selectivity, linearity, sensitivity, accuracy, repeatability, within-laboratory reproducibility, limit of determination, and limit of quantitation were determined during the validation procedure. The method proved to be applicable for both qualitative and quantitative determination of the ten above-mentioned target compounds. In our in-house fermentation experiments, milk fortified with coccidiostats was fermented to get yoghurt, kefir, and sour cream. Our results show that the coccidiostat content did not change significantly during fermentation for any of the target compounds.     

Determination of Coccidiostats in Milk Products by LC–MS and Its Application to a Fermentation Experiment

A liquid chromatographic tandem mass spectrometric (LC–MS–MS) method for the determination of five chemical coccidiostats (decoquinate, diclazuril, halofuginone, nicarbazin, and robenidine) and five ionophore coccidiostats (maduramicin, monensin, narasin, salinomycin, and semduramicin) in yoghurt, kefir, and sour cream is presented. Lasalocid, the sixth ionophore listed in 124/2009/EC was not included because of its extremely dissimilar behavior during sample preparation. Main steps of the method include extraction with acetonitrile, centrifugation, clean-up on Oasis HLB solid phase extraction cartridge, evaporation under nitrogen stream, and LC–MS–MS determination. Selectivity, linearity, sensitivity, accuracy, repeatability, within-laboratory reproducibility, limit of determination, and limit of quantitation were determined during the validation procedure. The method proved to be applicable for both qualitative and quantitative determination of the ten above-mentioned target compounds. In our in-house fermentation experiments, milk fortified with coccidiostats was fermented to get yoghurt, kefir, and sour cream. Our results show that the coccidiostat content did not change significantly during fermentation for any of the target compounds.

     

Voltammetric Behavior and Reliable Method for the Determination of Coccidiostat Robenidine in Animal Feed and Poultry Meat

The voltammetric behaviour of coccidiostat robenidine was investigated. The outcomes have revealed that reduction of robenidine causes an appearance of one diffusion-controlled cathodic peak on a static mercury drop electrode (SMDE) and a silver solid amalgam electrode (p-AgSAE). The influence of pH, a supporting electrolyte, a scan rate and accumulation parameters was evaluated. The mechanism of robenidine reduction involving two electrons and one proton was studied for the first time. The calibration curves with the wide linear concentration ranges (more than two concentration orders) were obtained under optimized experimental conditions and operating parameters. The reduction current linearly increases when increasing the concentration of coccidiostat. The methods of voltammetric determination of robenidine in feed and meat have been developed. The limits of quantitation of the methods of robenidine determination in feed are 9.5 mg/kg and 2.5 mg/kg on SMDE and p-AgSAE, respectively. Calculated recoveries ranges of robenidine were between 88.8 % and 101.5 %.     

Multi-residue confirmatory method for the determination of twelve coccidiostats in chicken liver using liquid chromatography tandem mass spectrometry

The confirmatory LC-MS/MS method for the determination of residues for twelve coccidiostats including ionophore antibiotics (lasalocid, maduramycin, monensin, narasin, salinomycin, semduramycin) and chemical coccidiostats (clazuril, decoquinate, diclazuril, halofuginone, nicarbazin and robenidine) in poultry liver has been developed. The sample preparation was based on extraction with acetonitrile, defatting with Alumina columns and clean-up on Oasis HLB spe. The separation of analytes was performed on PhenylHexyl column with a gradient of acetonitrile, methanol and the ammonium formate pH 4.0. For all analytes, at least 2 diagnostic fragmentation ions were monitored. The validation, performed according to the CD 2002/657/EC, proved the suitability of the method for the confirmatory analysis of the coccidiostats. For lasalocid, however, low reproducibility was observed and the proper quantification could not be performed with this method.     

Determination of cigarette papers moisture content by gas chromatography

A method for the determination of the moisture content in cigarette papers using solvent extraction followed by gas chromatographic analysis was developed. Optimal extraction conditions, including the agitation method, solvent and extraction time, as well as optimal gas chromatographic parameters, such as the internal standard, were investigated. The maximum degree of moisture extraction was achieved when samples were soaked in 20 mL of ethanol containing 0.5 mL L^?1 of isopropanol as an internal standard for 50 min under ultrasonic agitation. The method showed good linearity over the concentration range from 0.26 mass % to 10 mass % of the moisture content with a correlation coefficient of 0.99998. The recovery (102.1–109.3 %) and precision (relative standard deviation: 1.64 %) of the method were examined by analyzing various cigarette paper samples. The method was successfully applied to different types of paper and it exhibits superior accuracy and high efficiency compared with the existing methods of moisture determination.     

Quantitative determination of fluoxetine in human serum by high performance thin layer chromatography

A high performance thin layer chromatographic method was developed and validated for the quantification of fluoxetine in human serum. Fluoxetine was extracted by liquid–liquid extraction method with diethyl ether as extraction solvent. Imipramine was used as internal standard. The chromatographic separation was achieved on precoated silica gel F 254 high performance thin layer chromatographic plates using a mixture of toluene/acetic acid glacial (4:5 v/v) as mobile phase. 4‐Dimethylamino‐azobenzene‐4‐sulphonyl chloride was used as derivatization reagent. Densitometric detection was done at 272 nm. The method was linear between 12.5 and 87.5 ng/spot, corresponding to 0.05 and 0.35 ng/μL of fluoxetine in human serum after extraction process and applying 25 μL to the chromatographic plates. The method correlation coefficient was 0.999. The intra‐assay and inter‐assay precisions, expressed as the RSD, were in the range of 0.70–2.01% (n=3) and 0.81–3.90% (n=9), respectively. The LOD was 0.23 ng, and the LOQ was 0.70 ng. The method proved be accurate, with a recovery between 94.75 and 98.95%, with a RSD not higher than 3.61% and was selective for the active principle tested. This method was successfully applied to quantify fluoxetine in patient serum samples. In conclusion, the method is useful for quantitative determination of fluoxetine in human serum.     

Fast determination of ochratoxin A in serum by liquid chromatography: comparison with enzymic spectrofluorimetric method.

A rapid high-performance liquid chromatographic method for the determination of low concentrations of ochratoxin A in serum is described. The extraction procedure was simple and short, and liquid chromatographic analysis was carried out isocratically on a reversed-phase C18 column, with methanol-water-acetic acid (30:70:1) as mobile phase and fluorescence detection (excitation at 336 nm, emission at 465 nm). The examined concentration range, 5-50 ng/ml ochratoxin, the recovery method was 87-94%, compared with 62-67% for the enzymic spectrofluorimetric method. The high-performance liquid chromatographic method was faster because the extraction procedure was shorter, and more sensitive so that small sample volumes could be used.     

Simultaneous determination of methylxanthines in different types of tea by a newly developed and validated TLC method

The aim of this paper is to develop a new simple, fast and economical method for simultaneous quantitative determination of methylxanthine compounds based on TLC combined with image analysis. To obtain certain results, both extraction and chromatographic separation were optimized. The optimum extraction conditions were maceration in ethanol-water 8:2, v/v. The chromatographic separations were done on the silica gel F(254) TLC plates developed with chloroform-dichloromethane-isopropanol, 4:2:1 v/v/v. Detection was performed under UV lamp at 254?nm and the evaluation of the chromatographic plate was based on digital processing of chromatographic images. The developed TLC method was validated for parameters such as specificity, linearity and range, LOD and LOQ, precision, robustness and accuracy. This method was then applied for determination of caffeine, theobromine and theophylline in different types of tea, commercially available. Moreover, the content of methylxanthines detected and determined in commercial tea samples can be used as chemical marker in quality control.