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81.
建立了气相色谱仪测定广藿香油中百秋李醇含量的方法。用毛细管色谱柱DB-5MS(30m×O.32mm.0.25μm),正十八烷为内标,氢火焰离子化检测器进行检测,内标法定量。百秋李醇含量在0.2-2.0mg/mL范围内,百秋李醇峰面积和内标物峰面积之比与百秋李醇质量浓度呈良好的线性关系,相关系数r=0.9997。方法的检出限为1μg/mL,加标回收率为90.0%~100.6%,测定结果的相对标准偏差为1.22%(n=6)。研究表明,本法简便、快速、测定结果准确可靠,精密度优于外标法。 相似文献
82.
To the best of our knowledge, bioanalytical methods to determine rosiglitazone in human plasma reported in literature use internal standards that are not commercially available. Our purpose was to develop a simple method for the determination of rosiglitazone in plasma employing a commercially available internal standard (IS). After the addition of celecoxib (IS), plasma (0.25 mL) samples were extracted into ethyl acetate. The residue after evaporation of the organic layer was dissolved in 750 microL of mobile phase and 50 microL was injected on to HPLC. The separation was achieved using a Hichrom KR 100, 250 x 4.6 mm C(18) with a mobile phase composition potassium dihydrogen phosphate buffer (0.01 m, pH 6.5):acetonitrile:methanol (40:50:10, v/v/v). The flow-rate of the mobile phase was set at 1 mL/min. The column eluate was monitored by fluorescence detector set at an excitation wavelength of 247 nm and emission wavelength of 367 nm. Linear relationships (r(2) > 0.99) were observed between the peak area ratio rosiglitazone to IS vs rosiglitazone concentrations across the concentration range 5-1000 ng/mL. The intra-run precision (%RSD) and accuracy (%Dev) in the measurement of rosiglitazone were <+/-10.69 and <-12.35%, respectively across the QC levels (50-1000 ng/mL). The extraction efficiency was >80% for both rosiglitazone and IS from human plasma. The lower limit of quantitation of the assay was 5 ng/mL. In summary, the methodology for rosiglitazone measurement in plasma was simple, sensitive and employed a commercially available IS. 相似文献
83.
首次通过ICP-AES仪研究了分子筛化学组成全分析的方法,采用HNO3-HF混合酸密闭溶样,用H3BO3配合F^-,分别采用内标法和基体消除法消除基体效应.将研究结果与经典方法比较表明:采用本文研究的分析方法,结果准确可靠,符合分析要求,尤其对杂原子分子筛以及金属氧化物修饰的分子筛的组成分析具有应用价值. 相似文献
84.
An overview of analytical methodologies for the determination of antibiotics in environmental waters 总被引:3,自引:0,他引:3
The widespread occurrence of antibiotics as contaminants in the aquatic environment has increased attention in the last years. The concern over the release of antibiotics into the environment is related primarily to the potential for the development of antimicrobial resistance among microorganisms. This article presents an overview of analytical methodologies for the determination of quinolone (Qs) and fluoroquinolone (FQs), macrolide (MLs), tetracycline (TCs), sulfonamide (SAs) antibiotics and trimethoprim (TMP) in different environmental waters. The analysis of these antibiotics has usually been carried out by high-performance liquid chromatography (HPLC) coupled to mass spectrometry (MS) or tandem mass spectrometry (MS/MS) and to a lesser extent by ultraviolet (UV) or fluorescence detection (FD). A very important step before LC analysis is sample preparation and extraction leading to elimination of interferences and prevention of matrix effect and preconcentration of target analytes. 相似文献
85.
86.
87.
液相色谱-三重串联四极杆质谱测定粮油中的黄曲霉毒素 总被引:5,自引:0,他引:5
建立了超声提取-液相色谱-电喷雾三重串联四极杆质谱测定玉米、大米、大豆等粮油固体样品中黄曲霉毒素B1、B2、G1和G2(AFB1、AFB2、AFG1和AFG2)的方法。分析前对样品进行超声提取,优化得到最佳超声提取条件: 溶剂为甲醇-水(含40 g/L NaCl) (80:20, v/v)溶液、料液比为1:3(g:mL)、温度为50 ℃、时间为3 min。然后对提取的样品进行免疫亲和特异性净化。最后与液相色谱-电喷雾三重串联四极杆质谱联用,使用C18反相色谱柱,流动相为甲醇-10 mmol/L乙酸铵水溶液梯度洗脱,以黄曲霉毒素M1(AFM1)作为内标进行定量测定。结果表明,AFB1、AFB2、AFG1和AFG2的检出限分别为0.002、0.004、0.004和0.012 μg/kg。方法的加标回收率为87%~111%,日内相对标准偏差(RSD)和日间RSD分别不大于6.7%和5.6%。实验结果表明该方法可以有效地降低基质效应的影响,相比于外标法能极大地提高方法的准确度。 相似文献
88.
高效液相色谱-电喷雾电离三级四极杆质谱检测动物源食品中氯霉素、甲砜霉素、氟苯尼考残留量 总被引:6,自引:1,他引:6
建立了动物源产品中氯霉素、甲砜霉素、氟苯尼考残留量的高效液相色谱-电喷雾电离三级四极杆质谱(LC-ESI-MS/MS)的方法。前处理方法包括添加同位素内标氯霉素-d5,碱化乙酸乙酯提取,C18小柱净化。该方法采用负离子,多反应监测氯霉素四对离子(321.0/151.9,321.0/256.6,321.0/194.2,321.0/175.4),甲砜霉素两对离子(354.1/185.0,354.1/290.0),氟苯尼考两对离子(356.0/335.9,356.0/185.1)和同位素内标氯霉素-d5(326.0/157.1)。该方法线性范围为0.1~1.6μg/kg;对不同基质样品的加标回收率为80%~112.5%;相对标准偏差小于11%;方法的测定低限为0.1μg/kg。 相似文献
89.
In this paper,the nonlinear dynamic behavior of a string-beam coupled system subjected to external,parametric and tuned excitations is presented.The governing equations of motion are obtained for the nonlinear transverse vibrations of the string-beam coupled system which are described by a set of ordinary differential equations with two degrees of freedom.The case of 1:1 internal resonance between the modes of the beam and string,and the primary and combined resonance for the beam is considered.The method of multiple scales is utilized to analyze the nonlinear responses of the string-beam coupled system and obtain approximate solutions up to and including the second-order approximations.All resonance cases are extracted and investigated.Stability of the system is studied using frequency response equations and the phase-plane method.Numerical solutions are carried out and the results are presented graphically and discussed.The effects of the different parameters on both response and stability of the system are investigated.The reported results are compared to the available published work. 相似文献
90.