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1.
薄层分离-库仑滴定法测定茄尼醇   总被引:17,自引:0,他引:17  
提出以2mol/LKBr-醋酸(1:3V/V)为电液,在阳极电生溴与尼醇发生反应来测定茄尼醇含量的库仑滴定法。茄尼醇与溴反应,其n值为18,对于烟叶以物中茄尼醇,以正己烷-二氯乙烷-丙醇为展开剂,用薄层色地邓以分离,用库仑滴定法进行测定 。  相似文献   

2.
废次烟叶中茄尼醇的超声提取及HPLC分析测定   总被引:14,自引:0,他引:14  
废次烟叶中茄尼醇的超声提取及HPLC分析测定;超声提取;高效液相色谱;废次烟叶;茄尼醇  相似文献   

3.
高效液相色谱法同时测定烟叶中茄尼醇和辅酶Q10的含量   总被引:5,自引:0,他引:5  
高效液相色谱法同时测定烟叶中茄尼醇和辅酶Q10的含量;反相高效液相色谱;二级管阵列检测器;烟叶;茄尼醇;辅酶Q10  相似文献   

4.
邻硝基苯基荧光酮褪色分光光度法测定痕量钴   总被引:6,自引:0,他引:6  
研究了Co(Ⅱ)在碱性介质催化过化氢氧化邻硝基苯基荧光酮(o-NPF)这一主影响反应 因素,建立了测定痕量Co(Ⅱ)的新方法。灵敏度为4.3×106-10g/L;测定范围为0 ̄0.5ng/25mL方法简便快速,用于药物维生素B12中Co(Ⅱ)含量的测定,样品分析结果良好。  相似文献   

5.
酪氨酸酶电流传感器测定低浓度氰化物抑制剂的研究   总被引:1,自引:0,他引:1  
用预活化聚酰胺膜固定酪氨酸酶,制得性能良好的酪氨酸酶生物传感器,以此测定CN~-抑制剂的含量。在磷酸盐缓冲溶液中,以苯酚作底物,浓度范围为5×10~(-6)~4×10~(-5)mol/L,当苯酚浓度一定时,还原电流(-0.200V,vs,SCE)的下降值与CN~-浓度的平方根成线性关系,检测范围为5×10~(-7)~2×10~(-4)mol/L,有良好的选择性和重现性。  相似文献   

6.
苯酚对固定在增塑的聚氯乙烯(PVC)敏感膜中的2,2,7,7,12,12,17,17-八甲基-21,22,23,24-四氧杂四烯(TOE)有可逆荧光增强作用,据此研制了测定水溶液中苯酚含量的荧光化学传感器。该敏感膜最佳组成为:50mg PVC、100mg癸二酸二异辛脂(DOS)、1.5 mg TOE。该传感器在pH7.4的 Tris/HCl缓冲溶液中,对苯酚的线性响应范围为4.47×l0~(-6)~4.17×10~(-3)mol/L;检出限为6.30×l0~(-7)mol/L;其响应时间小于30s。该传感器具有良好的重现性、可逆性和选择性,常见阴离子和阳离子不干扰测定。该传感器应用于工业废水中苯酚含量的测定,结果满意。  相似文献   

7.
研究了新试剂-N间甲苯基-N’-(氨基对苯磺酸钠)硫脲(MMPT)与铂(Ⅳ)的显色反应,结果表明,在 pH 3.7~4.4的 HAc-NaAc缓冲体系中,Pt(Ⅳ)与 MMPT形成 1:3的绿色水溶性络合物,最大吸收波长位于 754.4 nm,表观摩尔吸光系数ε754.4=8.58 × 104·mol-1·cm-1,铂含量在0~1.28 mg/L的范围内服从比尔定律。本法灵敏度高、选择性好、操作简便、测定结果准确可靠。将其用于矿石和催化剂中铂的测定,结果令人满意。  相似文献   

8.
铝—酸性铬蓝K荧光光度法测定微量铝的研究   总被引:6,自引:1,他引:5  
杨维平  章竹君 《分析化学》1994,22(6):602-604
研究了酸性铬蓝K(ACBK)荧光光度法测定微量铝的反应。Al^3+与ACBK形成络合物的荧光强度与铝的含量在1×10^-8~8×10^-6mol/L范围内呈现良好的线性关系,检测限为4.8×10^-9mol/L,对4×10^-8mol/L铝重复11次检测其相对标准偏差为4.8%,成功地用于人发及钢样中铝含量的测定。  相似文献   

9.
研究了2-(3,5-二氯-2-吡啶偶氮)-5-二甲氨基苯胺与铂(Ⅳ)的显色反应,在pH3.5~6.0醋酸-醋酸钠介质中,沸水浴加热25min,试剂与铂(Ⅳ)形成1:4的紫色配合物,再提高酸度至2.9~4.0mol/L盐酸溶液,其最大吸收峰红移至630nm,灵敏度显著提高,表现摩尔吸光系数ε_(600)=7.0×10 ̄4L·mol ̄(-1)·cm ̄(-1),铂含量在0~32μg/25mL范围内符合比耳定律。大多数常见金属离子不干扰测定,所拟方法操作简便,用于催化剂中微量铂的测定,结果满意  相似文献   

10.
胶束毛细管电泳法测定牡丹皮及芍药中牡丹酚和芍药甙   总被引:32,自引:0,他引:32  
用胶束毛细管电泳地(MECC)测定牡丹皮、白芍、赤芍及其不同炮制品的牡丹酚、芍药甙的含量,以30mmol/L磷酸盐缓冲溶液(NaH2PO4-Na2HPO4)中含20mmol/L十二烷基硫酸钠(SDS)的表面活性剂电解质,PH=6.85,于254nm紫外检测,实验结果线性关系良好。塔数达到4.6×10^4。  相似文献   

11.
A rapid and simple method is described for the simultaneous determination of methyl, ethyl, isopropyl, n-propyl, isobutyl and n-butyl p-hydroxybenzoic acid esters (parabens) in cosmetics by high-performance liquid chromatography (HPLC). The method involves a single extraction of parabens with diethyl ether and clean-up on a Sep-Pak Florisil cartridge. Fat-soluble excipients in the diethyl ether extracts are removed through the cartridges with hexane-chloroform (75:25). Parabens are then eluted from the cartridges with hexane-ethyl acetate (70:30) and determined by HPLC on a reversed-phase column with water-methanol (50:50) as the mobile phase using sec.-butylpraben as an internal standard. The method was applied to samples with complicated matrices such as cream, milk lotion, lotion and cleansing foam, and the recoveries were 99.0-102.3% with coefficients of variation of 0.3-1.2%.  相似文献   

12.
用液相色谱/大气压化学电离离子阱质谱建立了一种分析烟草中游离茄尼醇的方法。烟草样品用甲醇振荡提取30 min,在分析前无需进行其它前处理。在1.8μm快速分离C18色谱短柱上用V(甲醇)∶V(异丙醇)=85∶15等梯度洗脱实现了茄尼醇的快速分离。用不带碰撞能量的二级质谱全扫描选择监测离子m/z 613.6进行定量,检出限为0.4μg/L,RSD为1.1%,两种添加量的回收率分别为97%和99%。方法应用于不同烟草和烟草制品样品的检测分析。  相似文献   

13.
烟草各部位中茄尼醇含量分布研究   总被引:1,自引:0,他引:1  
采用Kromsil ODS-1色谱柱,V(甲醇)∶V(乙醇)=55∶45混合液为流动相,在紫外检测波长设定为211 nm的高效液相色谱条件下测定了烟草中各部位提取物中的茄尼醇,其中烟叶中茄尼醇的质量分数为0.45%,其他部位茄尼醇的质量分数为:烟梗0.037%,烟茎0.0037%,烟根0.0037%,其中烟叶中的茄尼醇量最高,具有提取价值.  相似文献   

14.
高效液相色谱法测定烟叶提取物中茄尼醇的含量   总被引:29,自引:0,他引:29  
张明时  黄俊学 《色谱》2001,19(5):470-471
 采用硅胶色谱柱 ,以正己烷 异丙醇 (体积比为 98∶2 )混合液为流动相 ,在紫外检测波长设定为 2 15nm的高效液相色谱仪上测定了烟叶提取物中茄尼醇的含量。实验结果表明 :方法在茄尼醇进样量为 1μg~ 10 μg时有良好线性关系 (Y =16 6 2 0 4X - 32 5 3,r=0 9997) ;加标回收实验 (n =6 )的平均回收率为 98 1% ,RSD为 1 9% ;方法简便 ,有良好的精密度和准确性。  相似文献   

15.
Dayan lignite was subjected to thermal dissolution sequentially with cyclohexane, acetone, and methanol. Each thermal dissolution extract was subjected to further separation/enrichment using column chromatography, which was sequentially eluted with petroleum ether, a mixture of ethyl acetate and petroleum ether (vol:vol = 1:1), and ethyl acetate. The three thermal dissolution extracts and nine enrichment subfractions were characterized by an Orbitrap mass spectrometry equipped with an atmospheric pressure chemical ionization ion source. The mass spectrometry data were also statistically analyzed by principal component analysis, which can reduce the dimensionality of data and classify multiple samples according to principal components. Identified compounds in the extracts and subfractions are classified into eight classes according to the heteroatom distribution. Hydrocarbon class is mainly presented in the petroleum ether fraction, and oxygen class, nitrogen class, and oxygen‐nitrogen class are distributed in both petroleum ether/ethyl acetate and ethyl acetate subfractions. The combination of different analytical methods enhances the understanding of coal at the molecular level and provides important data for downstream refining processes.  相似文献   

16.
徐效华  官智  曾陇梅  苏镜娱 《色谱》1999,17(3):225-228
 从西沙群岛海区采集的小刺豆荚软珊瑚(Lobophytummicrospiculatum)中,通过乙醇提取、乙酸乙酯-水分配、硅胶色谱分离和GC/MS分析等方法,分离、鉴定出11种甾醇。其中柳珊瑚甾醇(11)的质量分数占65.6%。22,24-二甲基-胆甾-5,22(23)-二烯-3β-醇(4)是首次从自然界发现的新化合物,它的发现为柳珊瑚甾醇的生源假说提供了进一步佐证。  相似文献   

17.
The infrared laser induced decomposition of mixtures of ethyl acetate and isopropyl bromide has been studied. The ratio of the yields of products ethylene and propylene, arising from the unimolecular decomposition reactions: ethyl acetate → ethylene + acetic acid, and isopropyl bromide → propylene + hydrogen bromide, were measured as a function of the ratio of ethyl acetate to isopropyl bromide and pressure of added helium. The results indicate clearly that in these systems non-equilibrium behavior is found up to the highest pressures used (about one atmosphere). A two level kinetic model is suggested which qualitatively explains the observations.  相似文献   

18.
气相色谱法测定茶叶中多种有机磷农药残留量   总被引:50,自引:2,他引:48  
张莹  黄志强  李拥军 《色谱》2001,19(3):273-275
 采用微量化学法和全自动固相萃取技术 ,建立了气相色谱法同时测定茶叶中 14种有机磷农药残留量的方法 ,并对样品的前处理作了一定的探讨。结果表明 ,采用程序升温 ,所测定的 14种有机磷农药在SPBTM 170 1石英毛细管柱上得到了很好的分离 ,且方法快速、灵敏 ,完全符合实际应用需要。  相似文献   

19.
The solubility of valsartan in ethyl acetate + (butanone, isopropyl ether) binary solvent mixtures was measured at temperatures = 278.15–323.15 K and pressure = 0.1 MPa with a laser monitoring dynamic technique by a synthetic method. The experimental data were regressed by the modified Apelblat equation, the general single model and the hybrid model. The experimental data are well correlated with the above models because the mean deviations (MDs) are less than 3.79%. The mole fraction solubility of valsartan increases with increase in temperature and enrichment in butanone content, while it decreases with increased mole fraction of isopropyl ether at constant temperature. In addition, thermodynamic studies, including Gibbs energy, entropy and enthalpy, were calculated by van’t Hoff analysis. The results showed that the dissolution of valsartan in mixed solvents is endothermic, spontaneous and entropy-driven.  相似文献   

20.
Binary azeotropic data have been measured at different pressures for ethyl acetate + heptane, methyl acetate + heptane, isopropyl acetate + hexane and isopropyl acetate + heptane by means of a wire band column. Additionally activity coefficients at infinite dilution have been determined for ethyl acetate and isopropyl acetate in decane and dodecane in the temperature range between 303.15 and 333.15 K with the help of the dilutor technique. Furthermore excess enthalpies for the binary systems methyl acetate + hexane, methyl acetate + decane, ethyl acetate + hexane and ethyl acetate + decane at 363.15 and 413.15 K have been studied with the help of isothermal flow calorimetry. Finally solid–liquid equilibria for the systems ethyl myristate + benzene and ethyl myristate + p-xylene have been investigated by a visual technique. All these data have been used for the revision and extension of the group interaction parameters of the group contribution method modified UNIFAC (Dortmund) and the group contribution equation of state VTPR. The experimental data was compared with the results predicted using the group contribution method modified UNIFAC (Dortmund) and the group contribution equation of state VTPR.  相似文献   

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