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超高效液相色谱串联质谱法测定银杏中氨基甲酸酯类农药残留 总被引:1,自引:0,他引:1
建立了银杏叶中15种氨基甲酸酯类农药残留量的超高效液相色谱一串联质谱测定方法。样品经乙腈提取,TPT固相萃取柱净化,通过XTerra MS Cl8色谱柱分离,供串联质谱测定。15种氨基甲酸酯类农药在0.02-0.5mg/L范围内线性良好,相关系数为0.9962-0.9999;在0.004,0.01,0.02,0.04mg/kg4个添加水平下,其平均回收率为65.22%-96.66%,相对标准偏差为1.43%-10.06%(n=5)。该方法净化效果好、灵敏度高、重现性好,可满足银杏叶中15种氨基甲酸酯类农药残留量的检验要求。 相似文献
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以SBA-15和氨基功能改性的SBA-15/NH2为载体,采用浸渍法制备了固载磷钨酸催化剂,通过FT—IR光谱,Raman光谱,XRD衍射分析,N2-吸附脱附实验,TEM和NH3-TPD等手段对催化剂进行表征.结果表明,磷钨酸在两种载体上均保持Keggin结构,载体的介孔结构没有明显破坏.在高固载量情况下,磷钨酸在SBA-15载体上发生晶相聚集,介孔孔道发生堵塞使比表面积、孔容和孔径明显减小.在SBA-15/NH2载体上,磷钨酸与载体发生酸碱作用,能够均匀分散于SBA-15/NH2的孔道中,但催化剂酸性有所降低.考察了相同固载量的两种催化剂对苹果酯合成反应的催化活性,结果表明,以SBA-15/NH2为载体的催化剂具有良好的重复使用性能. 相似文献
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SBA-15介孔分子筛表面的磺酸基改性及其催化性能 总被引:28,自引:0,他引:28
采用后合成方法,将含有巯基的化合物3-巯丙基三甲氧基硅烷(MPTMS)键合在大孔径、厚孔壁的新型纯硅介孔分子筛SBA-15表面上,经氧化和酸化后得到含有强酸性的磺酸基团的固体酸催化剂SBA-15-SO3H.用X射线衍射、红外光谱、固体核磁共振及热失重等方法对改性前后的SBA-15样品进行了表征.结果表明,改性后SBA-15分子筛的结构未发生变化,MPTMS键合于分子筛的表面,改性后的分子筛具有质子酸中心.SBA-15-SO3H催化剂对十八碳烯酸与甲醇的酯化反应具有较高的活性,催化剂上的磺酸基团在反应过程中具有较好的稳定性. 相似文献
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铂单晶电极表面下不可逆反应动力学(III) 总被引:5,自引:0,他引:5
在本系列研究论文Ⅰ[1]和Ⅱ[2]报导的结果基础上,进一步发展动力学数据解析方法.通过改变反应体系的温度,首次获得甲酸在Pt(100),Pt(110),Pt(111)电极上直接氧化反应的表观活化Gibbs自由能(△G≠0).在实验选定的标准状态下,即0.0V/SCE、298.15K和1.013×105Pa下,来算得到。还发现传递系数β在实验温度范围(283.15~303.15K)不随温度变化,但随电极表面原子排列结构变化,大小次序与△G≠0的变化一致. 相似文献
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NaCl、KCl在蔗糖水溶液中的粘度 总被引:2,自引:0,他引:2
报导了在298.15及308.15K下,NaCl、KCl在含有蔗糖5,10,15,20,25%(质量分数w)的水溶液中的密度及粘度数据.计算了在无限稀释条件下,NaCl和KCl在该体系中的粘度B系数及偏摩尔体积.结果发现:两种电解质的B系数随蔗糖含量的增加及温度的升高而增大且对蔗糖水溶液的结构起破坏作用.讨论了该三元体系内部溶质-溶质、溶质-溶剂间的相互作用,同时应用流动过渡状态理论计算了两种电解质在各组成下蔗糖水溶液中的流动活化参数 相似文献
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本文在恒定异丙醇摩尔分数x=0.05的条件下, 应用电动势法测定无液体接界电池(A)和电池(B)的电动势:Pt, H_2(latm)|HCl(m), 2-propanol(x), H_2O(1-x)|Agcl-Ag (A)和Pt, H_2(latm)|HCl(m_A), NaCl(m_B), 2-propanol(x), H_2O(1-x)|AgCl-Ag (B)根据电池(A)电动势确定混合溶剂中的Ag-AgCl电极的标准电极电势, 讨论了HCl的迁移性质; 利用电池(B)电动势确定HCl在该体系中的活度系数γ_A, 在恒定总离子强度下, HCl的活度系数遵守Harned规则。在溶液组成恒定时, logγ_A是温度倒数1/T的线性函数, 讨论了混合物中HCl的相对偏摩尔焓, 计算了HCl的一级、二级和总介质效应。 相似文献
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The thermodynamic properties of HCl-NaCl-d-Glueose-H_2O system was studied by emf measurement without liquid junction. Pt, H_2(1.013×10~5 Pa)|Hel(m), d-Glucose(x), H_2O(1-x)| Agel-Ag (A) Pt, H_2(1.013×10~5Pa)|HCl(m_A), NaCl(m_B), d-Glucose(x), H_2O(1-x)|AgCl-Ag (B) at the mass percentage of d-Glucose x=5%, 15% and 20% in the mixed solution, from 5 to 45 ℃, for cell (B) at constant total ionic strength I=1.00 mol·kg~(-1). The standard electrode potential of Ag-AgCI in the mixed solution have been determined from cell (A). The activity coefficients of HCl, γ_A, in the mixed solution system have been determined from cell (B). The results show that the activity coefficients of HCl in HCl-NaCl solutions still obeye Harned Rule. The standard transfer Gibbs free energies of HCl have calculated. The primary, secondary and total medium effect of HCl have been calculated. 相似文献
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EMF measurement of cell (A) and cell (B) Pt, H_2(g,101.325 kPa) |HCl(m_1),20 mass% Glucose, 80 mass% H_2O|AgCl-Ag (A) and Pt, H_2(g,101.325 kPa)|HGCl(m_1),G(m_2), 20 mass% Glucose, 80 mass% H_2O|AgCl-Ag (B) at 5 temperatures ranging from 278.15 to 318.15 K were used to derive (a) the standard emf of the cell with 20 msas% glucose-water. (b) the dissociation constant of glycine by two methods, that is, tradition Debye-Hückel extrapolation and polynomial approximation proposed by us in our former paper. The results obtained from both methods are in good agreement within experiment error. 相似文献
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A. N. Ermakov I. K. Larin Yu. N. Kozlov A. P. Purmal’ 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2006,80(12):1895-1901
The paper presents experimental data and an analysis of literature data on hydrogen peroxide forms in concentrated solutions of sulfuric acid, H2O2(aq), H3O 2 + (aq), and HSO 5 ? (aq). The thermodynamic constants of the parallel equilibria $\begin{array}{*{20}c} {H_2 O_2 (aq) + H_3 O^ + (aq) \Leftrightarrow H_3 O_2^ + (aq) + H_2 O (K_1 (298) = 8 \times 10^{ - 4} ),} \\ {H_2 O_2 (aq) + HSO_4^ - (aq) \Leftrightarrow HSO_5^ - (aq) + H_2 O (K_2 (298) = 1.2 \times 10^{ - 2} )} \\ \end{array} $ were determined. The activity coefficients of H2O2 and Henry constants for solutions of H2O2 in sulfuric acid were calculated. 相似文献
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本文在25 ℃下, 对0.01844—15.02 mol kg~(-1)浓度范围内的盐酸体系, 用自制Ag|AgGl电极和氢电极, 测定了Harned电池的电动势。在此基础上, 以玻璃电极代替氢电极, 测量上述盐酸体系的电动势, 计算了HCl的平均活度系数和H_2O的活度。实验结果表明, 玻璃电极在浓盐酸体系的“标准电势”是稳定的, 且遵从Nernst响应, 重现性良好, 响应速度快; 在高浓度和稀溶液中交替测量时, 电势无明显偏差。这说明电极有较好的可复性。求得的HCl的活度系数与文献值偏差小于1.2%。玻璃电极的“标准电势”的标准偏差为0.016%。 相似文献
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Theeffectofethanol-watermixtureontheseconddissociationconstantofcarbonicacidwasofinterestnotonlyforbiologistsbutalsoforchefestsandchemicalengineers,becauseitmayprovideusefulinformationinregardtotheidentificationofthenatureofthesesolute-solventinteractionpatternsinbinarysolventsystem"'.ThispaperreportStheseconddissociationconstantsofcarbonicacid,K,,atfivetemperaturesfrom278.15to318.15Kin5,15,25mass%ethanol-water"dxedsolventsdeterminedfrompreciseelnfmeasurementsincell(A)withoutliquidjunction:Pt… 相似文献
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Ionic interaction in the three systems Hcl-HEPES (N-2-hydroxyethylpiperazine-N′-2-ethanesulfonic acid), HCl-MOPSO (3-(N-Morpholino)-2-hydroxypropanesulfonic
acid), and HCl-glycine have been studied in terms of their mutual influence on the respective activity coefficients of each
component. Activity coefficients for each component of the three systems are calculated from emf measurements of solutions
containing HCl and the amino acid in a H2/solution/AgCl,Ag cell at 25°C. The first dissociation constant of HEPES at 25°C has also been determined using emf and pH
titration measurements. 相似文献
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The first thermodynamic dissociation constants of o-phthalic acid were determined at five temperatures from 278.15 to 318.15 K in 10, 14.93 and 20 wt% isopropanol-water solvent mixtures, by precise e. m. f. measurements of hydrogen-silver chlorld electrodes in cells without liquid junction. On the basis of Pitzer's theory, the method of polynomial approximation was used to determine the dissociation constants of H_2P and the results obtained were compared with traditional extrapolation according to the extended Debye-Huckel equation Results obtained from both methods agree within experimental error. The dependence of the first thermodynamic dissociation constant on temperature was given as a function of the thermodynamic temperature T by the empirical equation: pK_1=A_0+A_1/T+A_2/T. The thermodynamic quantities of dissociation in the mixed solvents have been calculated, and the results have been discussed. 相似文献