高效液相色谱法测定肉制品中甘草抗氧化物的含量

建立了测定肉制品中甘草抗氧化物含量的方法。样品经流动相提取,采用C．8色谱柱分离,以甲醇-0．2mol／L乙酸铵-冰乙酸（体积比70：29：1）为流动相,流速为1．0mL／min,波长为250nm,以保留时间进行定性,峰面积进行定量。甘草酸在1．0-80．0μg／mL范围内线性关系良好,回归方程为y=8．55×10^-5x-0．599（r=0．9997）,检出限为1．0mg／kg,定量限为3．0mg／kg,加标回收率为95．7％-103．4％,测定结果的相对标准偏差为1．57％-3．53％（n=6）。该方法适用于检验机构日常检验中大批量肉制品中甘草抗氧化物含量的测定。     

液相色谱-串联质谱法同时测定化妆品中的25种喹诺酮类药物

建立了直接提取结合液相色谱-电喷雾串联质谱同时测定化妆品中丹诺沙星、恩诺沙星、氟甲喹、恶喹酸、环丙沙星、沙拉沙星、萘啶酸、诺氟沙星、氧氟沙星等25种喹诺酮类药物的方法。样品经酸性乙腈提取和正己烷脱脂净化,采用Poroshell EC-C₁₈色谱柱分离,含0.1%甲酸的乙腈-水溶液为流动相进行梯度洗脱,电喷雾串联质谱正离子模式扫描,多反应监测(MRM)模式检测,外标法定量。实验通过空白基质液配制标准溶液,以降低基质对离子化干扰造成的基质效应,25种喹诺酮类药物在1~200 mg/kg范围内线性关系良好,相关系数(r)在0.999以上。方法的检出限为1.0 mg/kg,在1、5、10 mg/kg 3个加标水平下,水、乳、霜型化妆品中加标回收率为87.4%~105%,相对标准偏差(RSD)为4.54%~19.7%(n=6)。结果表明,该方法简便、快速、准确,适用于化妆品中25种喹诺酮类药物的测定。     

Rapid and sensitive determination of fatty acids in edible oil by liquid chromatography-electrospray ionization tandem mass spectrometry

A sensitive and robust on-line LC/MS method was developed for quantitative determination of linoleic acid,docosahexaenoic acid and docosanoic acid from edible oil samples.The oil samples were dissolved in chloroform-isopropyl alcohol(20:80,v:v)solution and the three fatty acids were separated by HPLC with a C4 column using 10 mmol/L ammonium acetate-isopropyl alcohol-acetonitrile(20:40:40,v:v:v)mobile phase in isocratic elution.Electrospray ionization mass spectrometry with the selected ion recording monitoring was used to detect and quantify the fatty acid.The calibration curves were linear in the range of 10.00–5000 pg/mL for linoleic acid and docosanoic acid,and 1.000–500.0 pg/mL for docosahexaenoic acid.The limit of detection was 2.0 pg/mL for linoleic acid,3.0 pg/mL for docosanoic acid,and 0.20 pg/mL for docosahexaenoic acid.The results showed that the method described in this paper could be utilized for rapid determination of three fatty acids at picogram levels in edible oils.     

Effective cleanup for the determination of six quinolone residues in shrimp before HPLC with diode array detection in compliance with the European Union Decision 2002/657/EC

A high‐performance liquid chromatographic method was developed for the determination of six quinolone residues (ciprofloxacin, enrofloxacin, sarafloxacin, oxolinic acid, nalidixic acid, and flumequine) in shrimp tissue samples. Separation was carried out by a LiChrospher® 100 RP‐8e column, running at a 22 min gradient elution program, and the mobile phase consisted of citric acid (0.4 mol/L), acetonitrile and methanol. Detection was achieved by a diode array detector, monitoring at 255 and 275 nm. Sample preparation included initial extraction with citric acid solution and further clean‐up by solid‐phase extraction, employing Lichrolut RP‐18 cartridges. Validation was performed according to the European Union Decision 2002/657/EC. The detection capability was 127.2 μg/kg for ciprofloxacin, 115.2 μg/kg for enrofloxacin, 126.2 μg/kg for sarafloxacin, 113.1 μg/kg for oxolinic acid, 125.2 μg/kg for nalidixic acid, and 239.0 μg/kg for flumequine. Recoveries ranged between 83.0 and 121.6%. The Youden test was applied to study the method ruggedness.     

Determination of melamine residue in liquid milk by capillary electrophoresis with solid-phase extraction

A novel solid-phase extraction-capillary electrophoresis (SPE-CE) method was developed for the determination of melamine residue in liquid milk. The conditions of SPE and CE were investigated and optimized. A 1% trichloroacetic acid plus 2.2% lead acetate solution were used for the extraction of analyte and the removal of protein. A Cleanert PCX SPE cartridges column was used for clean up. The 50 mM sodium dihydrogenphosphate running buffer (pH adjusted to 3.2 with citric acid) was used as a running buffer. The linearity is satisfactory in the range of 0.8-100 μg/mL with a correlation coefficient of 0.9998. Under the optimal conditions, the method limit of detection (LOD) and method limit of quantification were 0.12 mg/kg and 0.37 mg/kg, respectively. The recovery of melamine from different liquid milk samples was in the range of 89.5-98.5% with a relative standard deviation of 1.8-3.5%. The intra- and inter-day assay precision was 2.8% (n = 6) and 4.1% for five days, respectively. The developed method has been applied successfully for the determination of melamine residue in liquid milk samples. The results obtained by the proposed method agree with those obtained by high-performance liquid chromatographic method. The proposed method enables the quantitative determination of melamine residues at levels as low as 0.37 mg/kg in different liquid milk.     

Direct determination of nalidixic acid in urine by matrix isopotential synchronous fluorescence spectrometry

A new method for the determination of nalidixic acid in urine is proposed for concentrations between 25 and 1000 ng ml(-1) by means of matrix isopotential synchronous fluorescence spectrometry. This new technique is useful for the determination of compounds in samples with unknown background fluorescence, such as nalidixic acid in urine, without the need for tedious preseparation. The method was performed in ethanol/water medium (80% v/v), at an apparent pH of 2.9 provided by adding sodium monochloracetate/monochloroacetic acid buffer solution. The method was successfully applied to the determination of nalidixic acid in urine. Better sensitivity and reproducibility are achieved in these matrices than with the fluorimetric methods described in the literature.     

Gradient HPLC of antibiotics in urine, ground water, chicken muscle, hospital wastewater, and pharmaceutical samples using C-18 and RP-amide columns

A simple and highly sensitive high pressure liquid chromatographic (HPLC-UV) method has been developed for the determination of ofloxacin, lomefloxacin, cinoxacin, and nalidixic acid, in mobile phase citrate buffer (0.001 M) of pH 4.5 prepared in water (X), methanol (Y), and ACN (Z) using gradient at a flow rate of 1.0 mL/min by direct UV absorbance detection at lambda = 280 nm. Separation of analytes was studied on the C-18 and RP-amide columns and best results were observed on the RP-amide column with LODs (3.3 x S/m) 0.89, 0.55, 0.67, and 1.41 ng/mL for ofloxacin, lomefloxacin, cinoxacin, and nalidixic acid, respectively, and better RSD than the C-18 column. The recovery of Fluoroquinolones (FQs) in urine, ground water, hospital wastewater, and chicken muscle using this method is more than 90%. The method was successfully applied to the analysis of ofloxacin, lomefloxacin, cinoxacin, and nalidixic acid in urine, ground water, pharmaceutical dosage forms, hospital wastewater, and chicken muscle.     

Development of an HPLC multi-residue method for the determination of ten quinolones in bovine liver and porcine kidney according to the European Union Decision 2002/657/EC

A sensitive multi-residue analytical method was developed for the determination of ten quinolones: enoxacin, ofloxacin, norfloxacin, ciprofloxacin, danofloxacin, enrofloxacin, sarafloxacin, oxolinic acid, nalidixic acid, and flumequine in bovine liver and porcine kidney. A simple liquid extraction step followed by a solid phase extraction clean up procedure was applied for the extraction of quinolones from liver and kidney tissues. Recoveries of the extraction varied between 82 and 88% for bovine liver and 92 and 95% for porcine kidney. Separation was performed on an ODS-3 PerfectSil Target (250 x 4 mm) 5 microm analytical column at 25 degrees C. The mobile phase consisted of a mixture of TFA 0.1%-CH(3)CN-CH(3)OH, delivered at a flow rate of 1.2 mL/min according to a gradient program. Elution of quinolones and the internal standard (caffeine, 7.5 ng/microL) was complete within 27 min. Photodiode array detection was used for monitoring the eluants at 275 and 255 nm. The method was fully validated according to the European Union Decision 2002/657/EC, determining linearity, selectivity, decision limit, detection capability, accuracy, and precision. The LODs of the specific method of quinolone determination in bovine liver varied between 3 and 7 microg/kg and in porcine kidney between 3 and 4 microg/kg.     

基于纯水提取的烟熏鲣鱼中肌苷酸的提取方法

建立了一种基于纯水提取的新型烟熏鲣鱼中肌苷酸的提取方法。样品前处理采用95 ℃的纯水作为提取液,提取5 min。采用的色谱条件: 色谱柱为Agilent Zorbax SB-C18柱(150 mm×4.6 mm, 5 μm),柱温为30 ℃,流动相为甲醇-50 mmol/L乙酸铵水溶液(5:95, v/v),流速为1.0 mL/min,检测波长为254 nm。结果表明,该方法测定烟熏鲣鱼中肌苷酸含量的线性范围为1.0～120.0 mg/L;在0.40、2.00、4.00 g/kg (n=3)的添加水平下,回收率为84.6%～100.2%,测定结果的相对标准偏差(RSD)为1.00%～6.12%;检出限(信噪比(S/N)为3)为4 mg/kg;定量限(S/N=10)为12 mg/kg。该方法与常规采用的基于高氯酸的提取方法相比较,提取效率提高了37.0%,并且该方法操作安全、与环境友好,对烟熏鲣鱼中肌苷酸含量测定准确度良好,对其他食品中肌苷酸含量的测定具有借鉴意义,是一种值得推广的样品预处理方法。     

Single-laboratory validation of the biosense direct competitive enzyme-linked immunosorbent assay (ELISA) for determination of domoic acid toxins in shellfish

Method validation was conducted for an enzyme-linked immunosorbent assay (ELISA) for the determination of domoic acid (DA) toxins, known to give amnesic shellfish poisoning (ASP) symptoms, in shellfish. The calibration curve range of the assay is approximately 10-260 pg/mL, with a dynamic working range for DA toxins in shellfish from 0.01 to at least 250 mg/kg. The ASP ELISA showed no significant cross-reactivity to structural analogs, and proved to be robust to deliberate alterations of the optimal running conditions. The shellfish matrix effects observed with mussels, oysters, and scallops were eliminated by diluting shellfish extracts 1:200 prior to analysis, leading to a limit of detection at 0.003 mg/kg. Thirteen blank shellfish homogenates were spiked with certified mussel material containing DA to levels in the range of 0.1-25 mg DA/kg, and analyzed in quadruplicate on 3 different days. The relative standard deviation (RSD) under intra-assay repeatability conditions ranged from 6.5 to 13.1%, and under interassay repeatability conditions the RSD ranged from 5.7 to 13.4%, with a mean value of 9.3%. The recoveries ranged from 85.5 to 106.6%, with a mean recovery of 102.2%. A method comparison was conducted with liquid chromatography with ultraviolet detection, using naturally contaminated scallop samples (n = 27) with DA levels at 0-244 mg/kg. The overall correlation coefficient was 0.960 and the slope of the regression was 1.218, indicating a good agreement between the methods.     

固相萃取-高效液相色谱法测定蜂蜜中的有机酸

建立了固相萃取-高效液相色谱(SPE-HPLC)同时测定蜂蜜中5种有机酸(L-苹果酸、马来酸、琥珀酸、柠檬酸、D-苹果酸)含量的方法。蜂蜜经制样后过Bond Elutes SAX固相萃取(SPE)小柱净化,用C18-MS-II反相色谱柱(250 mm×4.6 mm, 5 μm)进行分离,流动相为2%偏磷酸溶液,流速为0.7 mL/min,检测波长为210 nm。在此条件下5种有机酸在相应的线性范围内其线性相关系数均大于0.9967;方法的回收率为86.0%～103.9%,相对标准偏差为5.7%～9.8%(n=6),检出限为0.06～9.4 mg/kg。所建立的方法可用于蜂蜜样品中有机酸的测定。     

Use of a microcolumn packed with modified carbon nanofibers coupled with inductively coupled plasma mass spectrometry for simultaneous on-line preconcentration and determination of trace rare earth elements in biological samples

In this work, a new method was developed for the determination of trace rare earth elements (REEs) in biological samples by inductively coupled plasma mass spectrometry (ICP-MS) after preconcentration on a microcolumn packed with modified carbon nanofibers (CNFs). CNFs oxidized with nitric acid have been proved to possess an exceptional adsorption capability for REEs due to their surface functionalization. The effects of the experimental parameters, including pH, sample flow rate and volume, elution solution and interfering ions, on the recoveries of the analytes have been investigated systematically. A 100-fold enrichment factor was obtained. The adsorption capacity of CNFs was found to be 18.1, 19.3, 23.6, 17.6, 22.3 and 19.5 mg/g for La, Ce, Sm, Eu, Dy and Y, respectively. Under the optimum conditions, the detection limits of this method ranged from 0.2 pg/mL (Dy) to 1.2 pg/mL (Ce) with an enrichment factor of 15-fold, and the relative standard deviations (RSDs) for the determination of REEs at the 1.0 ng/mL level were less than 4% (n = 9). This method was applied to the analysis of trace REEs in a real sample of human hair with recoveries of 95-115%. In order to validate the proposed method, a certified reference material of human hair (GBW 07601) was analyzed with satisfactory results.     

柱前衍生-高效液相色谱-荧光检测法测定罐头食品中的尿素

建立了罐头食品中尿素残留检测的柱前衍生-高效液相色谱-荧光检测方法.取5.0 g样品,经20 mL 1%(v/v)乙酸溶液提取、定容,离心后取上清液过滤,吸取0.5 mL提取液用呫吨醇进行衍生,采用高效液相色谱-荧光检测器进行测定.尿素在0.1~500 mg/L内线性良好,相关系数大于0.9995.实验表明,在5种罐头食品中各添加0.001~30 g/kg尿素,其平均回收率为80.2%~109.7%,相对标准偏差(n=6)为2.05%~6.53%,检出限为0.5 mg/kg,定量限为1.0 mg/kg.利用本研究建立的方法对168个实际样品进行测定,在3个肉类罐头样品中检出尿素,含量分别为10.6、62.1和2.6 mg/kg.方法稳定、可靠、操作简单,适用于罐头食品中尿素的检测.     

高效液相色谱法测定乳制品中的双氰胺

建立了乳制品中双氰胺的高效液相色谱(HPLC)检测方法。样品经乙腈提取后采用HPLC测定。优化后的色谱条件:XBridge Amide柱(250 mm×4.6 mm, 3.5 μm),流动相为乙腈和水(体积比为90:10,含0.2%甲酸),流速为1.0 mL/min,检测波长为218 nm。方法在0.5~50 mg/L范围内线性关系良好,相关系数(r²)为0.9999,回收率在96.7%~101.0%之间,RSD为4.5%~4.9%(n=6),检出限为0.2 mg/kg(S/N=3),定量限为0.5 mg/kg(S/N=10)。该方法简单、准确、灵敏度高,适用于各种乳制品中双氰胺的检测。     

高效液相色谱-串联质谱法测定调味料中的痕量苯甲酸与山梨酸

建立了调味料中痕量苯甲酸、山梨酸的高效液相色谱-串联质谱检测方法.调味料样品经盐酸酸化后用乙醚多次提取,酸性氯化钠洗涤提取液,挥干后用1 mL90% 0.2 mmol/L NH4OAc(pH 5.0)的乙腈溶液溶解,过膜备用.采用电喷雾负离子电离(ESI-)模式和单反应监控(SRM)模式检测,外标法定量.该方法在0.5...     

Simultaneous determination of 75 abuse drugs including amphetamines,benzodiazepines, cocaine,opioids, piperazines,zolpidem and metabolites in human hair samples using liquid chromatography–tandem mass spectrometry

A liquid chromatography–tandem mass spectrometric method for the simultaneous determination of 75 abuse drugs and metabolites, including 19 benzodiazepines, 19 amphetamines, two opiates, eight opioids, cocaine, lysergic acid diethylamide, zolpidem, three piperazines and 21 metabolites in human hair samples, was developed and validated. Ten‐milligram hair samples were decontaminated, pulverized using a ball mill, extracted with 1 mL of methanol spiked with 28 deuterated internal standards in an ultrasonic bath for 60 min at 50°C, and purified with Q‐sep dispersive solid‐phase extraction tubes. The purified extracts were evaporated to dryness and the residue was dissolved in 0.1 mL of 10% methanol. The 75 analytes were analyzed on an Acquity HSS T3 column using gradient elution of methanol and 0.1% formic acid and quantified in multiple reaction monitoring mode with positive electrospray ionization. Calibration curves were linear (r ≥ 0.9951) from the lower limit of quantitation (2–200 pg/mg depending on the drug) to 2000 pg/mg. The coefficients of variation and accuracy for intra‐ and inter‐assay analysis at three QC levels were 4.3–12.9% and 89.2–109.1%, respectively. The overall mean recovery ranged from 87.1 to 105.3%. This method was successfully applied to the analysis of 11 forensic hair samples obtained from drug abusers.     

Amnesic shellfish poisoning toxins in shellfish: estimation of uncertainty of measurement for a liquid chromatography/tandem mass spectrometry method

A liquid chromatography/mass spectrometry (LC/MS) method for amnesic shellfish poisoning toxins in shellfish was developed and validated. Tissue homogenate (4 g) was extracted with 16 mL methanol-water (1 + 1, v/v). Dilution into acetonitrile-water (1 + 9, v/v) was followed by C18 solid-phase extraction cleanup. Domoic acid (DA) and epi-domoic acid were determined by LC/MS/MS with electrospray ionization and multiple reaction monitoring. External calibration was performed with dilutions of a certified reference standard. Advantages of this method include speed, lower detection limits, and a very high degree of specificity. The LC/MS response was highly linear, and there were no significant interferences to the determination of DA. Formal method validation was performed on 4 shellfish species. Fortification studies gave recoveries (mean +/- SD; n = 24) of 93 +/- 14% at 1 mg/kg, and 93.3 +/- 7.6% at 20 mg/kg over all the species. Analysis of a mussel certified reference material showed the bias as < 5%. The limits of detection and quantitation were 0.15 and 0.5 mg/kg, respectively. Routine application of the method over 4 months gave a recovery for the QC sample (1 mg/kg fortified blank mussel homogenate) run with each batch of 88.9 +/- 5.5% (mean +/- SD; n = 37). The total uncertainty of measurement results were estimated as 0.12 (12%) at 0.25-5 mg/kg and 0.079 (7.9%) at 5-50 mg/kg. The major contribution to the uncertainty was the repeatability of the LC/MS determination, probably arising from subtle matrix effects.     

Determination of Antimony in Sediments by Zeeman-Corrected Electrothermal Atomic Absorption Spectrometry with Ultrasonic Slurry Sampling

A method was developed for the determination of antimony in slurried sediments (on the basis of samples of three Certified Reference Materials) by electrothermal atomic absorption spectrometry (ETAAS) with Zeeman-effect background correction. Slurried samples were prepared in 6% nitric acid containing 0.02% of Triton X-100. A mixed palladium/magnesium chemical matrix modifier, L'vov platform atomization and a temperature-time program with a relatively short (10 s) sample pyrolysis stage were used. The results of the determinations by this technique are in very close agreement with certified values and the repeatability of this analytical procedure expressed in terms of relative standard deviation was typically better than 9% at the slurry concentration of approx. 90 mg/2 mL. The characteristic mass of Sb (at the spectral line 231.1 nm) was 25.6 pg and the limit of detection (calculated for 100 mg/2 mL slurry) was about 0. 04 μg/g.     

微波辅助萃取-气相色谱法测定茶叶中的有机磷农药

建立了微波辅助萃取–气相色谱法测定茶叶中甲胺磷、乐果、毒死蜱、水胺硫磷、三唑磷5种有机磷农药残留量的分析方法。样品用乙酸乙酯微波辅助提取,提取液经分散固相萃取法(DSPE)净化,用气相色谱配FPD检测器测定,外标法定量。结果表明农药混合标准溶液在0.01～0.5μg/mL范围内线性良好(r>0.999),方法的检出限为0.005～0.01 mg/L,在0.05,0.125,0.5μg/mL 3个水平添加平均回收率为63.3%～99.9%,测定结果的相对标准偏差为5.1%～8.2%(n=6)。该方法适合于茶叶中多种有机磷农药残留量的同时检测。     

A rapid and sensitive UPLC–MS/MS method for quantitative determination of arformoterol in rat plasma,lung and trachea tissues

A rapid and sensitive ultra-performance liquid chromatography-tandem mass spectrometry (UPLC–MS/MS) method was developed and fully validated for determination of arformoterol in rat plasma, lung and trachea tissues.