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茯砖茶中黄酮的提取及含量测定 总被引:1,自引:0,他引:1
研究了茯砖茶中黄酮的最佳提取及测定条件,以95%乙醇为溶剂,加热回流提取茯砖茶中的黄酮,采用分光光度法检测黄酮含量.在料液比为1∶20g/mL,加热回流60min时,黄酮的提取率最高;当波长为416nm,0.1mol/LAlCl3-甲醇显色液与HAc-NaAc缓冲液(pH=4.0)的体积比为1∶1,显色时间为15min时,吸光度最大.对照样品的线性回归方程为A=0.0203+0.0176C(μg/mL),相关系数r=0.9997,线性范围10-50μg/mL,检出限2.5μg/mL;测得茯砖茶样品中黄酮的含量为1.80%,RSD为1.27%(n=5),对照样品的平均加标回收率为99.0%-102.8%.方法操作简便、快速、准确,能满足茯砖茶中总黄酮的提取和检测的要求. 相似文献
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建立了HPLC测定怀菊花中总黄酮含量的方法.采用Agilent C18柱(150mm×4.6mm,5μm),以甲醇(A)-超纯水(0.2%的冰乙酸)(B)(25∶75,V/V)为流动相,流速:0.5mL·min-1;柱温为20℃,检测波长:260nm;进样量:10μL.结果:回归方程为y=33.29x-8.284,r=0.9993(n=6),线性范围0-20μg,平均回收率为102.63%,RSD为5.56%.样品总黄酮含量为7.51mg/g.方法简便、灵敏、快速、准确、重现性好,可用于怀菊花中总黄酮含量的质量控制. 相似文献
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探讨了测定四大怀药中微量元素铁和锌的新方法.用高压密闭微波消解-火焰原子吸收法测定四大怀药——怀山药、怀菊花、怀地黄、怀牛膝等怀药中微量元素Fe和Zn的含量.铁的回归方程为y=0.0968x+0.0114,r=0.9995(n=6),线性范围0-6.4μg/mL,平均回收率91.29%-101.06%,RSD为1.334%-4.314%.样品铁含量为159.091-1535.64μg/g.锌的回归方程为y=0.4207x+0.0039,r=0.9996(n=6),线性范围0-1.2μg/mL,平均回收率93.58%-100.85%,RSD为1.145%-3.634%.样品锌含量43.571-70.357μg/g.微波消解法消解样品,具有省时、简便、经济、消解完全、污染少等特点,可用于怀药微量元素的测定. 相似文献
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建立了蜂蜜中10种大环内酯类抗生素的高效液相色谱-电喷雾串联质谱检测方法.比较了多种提取方法,最终采用缓冲溶液进行提取,用固相填料进行分散固相萃取净化.采用电喷雾离子源ESI,正离子扫描模式,选择M+H为监测离子,流动相为甲醇-0.1%甲酸水溶液梯度系统.在5.0-200.0μg/L范围内,10种大环内酯类抗生素的线性相关系数均大于0.99.通过阴性样品的加标回收实验,方法的定量限LOQ(S/N=10)为5.0μg/kg,检出限LOD (S/N=3)为1.0μg/kg,3个添加水平中,蜂蜜的加标回收率在60%-120%之间,日内相对标准偏差(RSD)在1.11%-9.26%之间.该法简单、灵敏、特异性强,适用于蜂蜜中大环内酯类药物残留的分析确证. 相似文献
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建立了电感耦合等离子体-质谱法(ICP-MS)测定尿中碘含量的方法.采用内标法和标准加入法测定尿中碘含量,样品无需前处理,2%硝酸溶液稀释后直接测定.该方法线性范围为2-60.00μg/L、相关系数为0.99995、回收率为95.2%-98.0%、相对标准偏差为1.07%-1.42%、检出限为0.0900μg/L,定量限为0.30μg/L.用ICP-MS和国标方法同时测定9份样品中碘含量,结果经配对T检验,T=1.8007,P>0.05结果差异无统计学意义.ICP-MS测定尿碘方法简便、快速、灵敏度高、干扰少、适合尿中碘含量的测定. 相似文献
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建立了高效液相色谱法测定祛痘类化妆品中禁用组分苯海拉明的含量。采用Inertsil CN-3色谱柱,流动相为乙腈-水-三乙胺(50∶50∶0.5,用冰醋酸调节pH至6.5),检测波长258nm,流速1.0mL/min,柱温25℃。苯海拉明在0.05—2.00mg/mL内呈良好线性(r=1.0000),平均回收率103.2%(RSD=0.70%,n=6);方法检出限(S/N=3)为50μg/g。该法操作简便,准确可靠,稳定性好,可用于祛痘类化妆品中苯海拉明的检测。 相似文献
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《光谱学快报》2013,46(4-5):389-403
Abstract This paper summarizes the application of stoichiometric analytical approaches to quantitative IR analysis and describes the development of a rapid and sensitive Fourier transform infrared (FTIR) method using such an approach for the determination of low levels (<0.005%) of free fatty acids (FFA) in refined edible oils. The method simply involves mixing the sample with methanol containing 2 g /L sodium carbodiimide (NaHNCN) on a vortex mixer for 30 s to convert the FFA to their salts, centrifuging the sample to separate the methanol phase containing the FFA salts from the oil, recording the FTIR spectrum of the upper methanol layer in a 100‐µm CaF2 transmission flow cell, and ratioing this spectrum against that of the NaHNCN/methanol solution. The concentration of FFA salts is determined from the resulting differential spectrum by measurement of the v(COO?) absorbance at 1573 cm?1 relative to a reference wavelength of 1820 cm?1. A calibration spanning the range 0–0.1% FFA (expressed as oleic acid) was devised by gravimetric addition of a defined, pure fatty acid to an acid‐free oil. Validation of the method by standard addition of palmitic acid to a variety of oils yielded an overall standard error of <±0.001% FFA. Comparison of triplicate FTIR and IUPAC titrimetric analyses of oils spiked with palmitic acid demonstrated that this FTIR method was more sensitive, accurate, and reproducible than the titration procedure, the latter having a significant positive bias of ~0.02%. Solvent/oil consumption in the FTIR method is 2 mL/10 g versus 150 mL/20 g for the titrimetric procedure. The FTIR method developed is particularly well suited for the determination of the low levels of FFA in refined oils but can readily be adapted with a simple adjustment of the oil/methanol ratio to cover FFA levels of up to 4.0%. 相似文献
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HPLC法对医学生血清维生素A含量的测定 总被引:1,自引:1,他引:0
建立快速提取血清中维生素A和运用HPLC测定其含量的方法。取待测血清200μL,加入无水乙醇液200μL,旋涡混合1min,再加入正己烷溶液400μL,旋涡混合3min,离心后取上清液,用高效液相色谱仪测定。色谱条件:分析柱为Kromasil100-5C18(150×4.6mm,5μm);流动相为甲醇∶水(98∶2,V/V);流速为1.2mL/min;检测波长为325nm。血清中维生素A分离良好,浓度在2—80μg/dL范围内呈线性关系,r2=0.9992。平均回收率为98.48%,日内、日间RSD均〈10%。所测医学生血清中维生素A的含量男性为(38.65±12.99)μg/dL,女性为(34.17±10.10)μg/dL。该法操作快速、样品处理简便易行,适用于血清中维生素A的快速提取和含量的测定。 相似文献
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Desorption electrospray ionization - orbitrap mass spectrometry of synthetic polymers and copolymers
Desorption ElectroSpray Ionization (DESI) - Orbitrap Mass Spectrometry (MS) was evaluated as a new tool for the characterization of various industrial synthetic polymers (poly(ethylene glycol), poly(propylene glycol), poly(methylmethacrylate), poly(dimethylsiloxane)) and copolymers, with masses ranging from 500 g.mol(-1) up to more than 20?000 g.mol(-1) . Satisfying results in terms of signal stability and sensitivity were obtained from hydrophobic surfaces (HTC Prosolia) with a mixture water/methanol (10/90) as spray solvent in the presence of sodium salt. Taking into account the formation of multiplied charged species by DESI-MS, a strategy based on the use of a deconvolution software followed by the automatic assignment of the ions was described allowing the rapid determination of M(n) , M(w) and PDI values. DESI-Orbitrap MS results were compared to those obtained from matrix-assisted laser desorption/ionization- time-of-flight MS and gel permeation chromatography. An application of DESI-Orbitrap MS for the detection and identification of polymers directly from cosmetics was described. Copyright ? 2012 John Wiley & Sons, Ltd. 相似文献
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利用超高效液相色谱串联质谱技术检测啤酒原料麦芽中的赤霉酸(Gibberellic acid,GA3)。样品由乙腈/水(80/20)提取后,经Oasis MAX固相萃取柱净化,以甲醇-甲酸水为流动相,梯度洗脱下,经选择离子模式(SIR)检测。结果表明,赤霉酸在ACQUITY UPLCTMBEH C18色谱柱上(2.1mm×100mm,1.7μm)得到较好分离,回收率为70%—78%,检出限0.6μg/L,RSD≤8.9%,该方法适用于麦芽等复杂体系中微量赤霉酸的检测。 相似文献