高效液相色谱-串联质谱法测定虾中万古霉素及去甲万古霉素残留量

建立了虾中万古霉素和去甲万古霉素残留量的高效液相色谱-串联质谱(HPLC-MS/MS)检测方法。样品经0.1%甲酸-乙腈(9∶1,体积比)混合溶液提取,乙腈饱和的正己烷除脂,PCX结合Florisil固相萃取柱进行净化后,以乙腈和0.1%甲酸溶液为流动相,经CAPCELL PAK MG-C18色谱柱分离后,采用高效液相色谱-串联质谱在多反应离子监测(MRM)模式进行测定,以双去氯万古霉素作为内标物,内标法定量。结果表明:万古霉素和去甲万古霉素在2~250 ng/m L范围内呈良好的线性关系,相关系数(r2)均大于0.99。在5,25,50μg/kg加标水平下,万古霉素和去甲万古霉素的平均回收率为87.2%~102%,相对标准偏差为1.3%~8.7%。方法的检出限(LOD)为2.0μg/kg,定量下限(LOQ)为5.0μg/kg。该方法灵敏、准确,重复性好,适用于虾类中万古霉素及去甲万古霉素残留量的测定。     

UPLC-MS/MS法测定猪肉中万古霉素与去甲万古霉素

建立了快速、准确、灵敏的猪肉中万古霉素和去甲万古霉素的超高效液相色谱串联三重四极杆质谱(UPLC-MS/MS)检测方法。样品经0.1%甲酸-乙腈(7∶3,体积比)提取,正己烷(乙腈饱和)脱脂后,以LC-C18固相萃取小柱净化,采用乙腈-0.1%甲酸为流动相进行梯度洗脱,串联质谱ESI正模式电离,多反应监测(MRM)模式检测,以保留时间和子离子比定性,外标法定量。结果表明,万古霉素和去甲万古霉素可在3 min内分离完全,在1～50μg/L范围内线性关系良好,相关系数均大于0.99,方法检出限(S/N=3)分别为0.5μg/kg和0.3μg/kg;加标水平为1～20μg/kg时(n=6),平均回收率为80%～88%,日内相对标准偏差不高于13.4%,日间相对标准偏差不高于12.5%。方法准确、灵敏,适用于猪肉中万古霉素和去甲万古霉素等糖肽类抗生素的测定。     

高效液相色谱-串联质谱法同时测定猪肝中万古霉素、去甲万古霉素和替考拉宁糖肽类抗生素

提出了同时测定猪肝中万古霉素、去甲万古霉素和替考拉宁的高效液相色谱-串联质谱方法。样品经乙腈-体积分数10%三氯乙酸(6+4,V/V)溶液提取,同时加入5 g(NH4)2SO4沉淀蛋白,以Oasis HLB固相萃取柱净化,采用乙腈-0.3%乙酸为流动相进行梯度洗脱,电喷雾离子源(ESI)正离子模式电离,多反应监测(MRM)模式检测,用基质匹配标准校准方法补偿基质效应,外标法定量。万古霉素、去甲万古霉素和替考拉宁在5~500μg/kg范围内呈线性,检出限分别为2.0,1.0和2.0μg/kg,在5.0,10.0,20.0μg/kg加标水平下(n=6),平均回收率为72.7%~87.0%,相对标准偏差均不高于8.2%。实验考察了标准溶液的稳定性。     

自动分散磁固相萃取—超高效液相色谱—串联质谱测定禽类产品中的万古霉素类抗生素

建立了一种禽类产品中万古霉素、去甲万古霉素和去氯万古霉素3种药物的自动分散固相萃取(AdSPE)-超高效液相色谱-三重四极杆串联质谱(UPLC-QqQ-MS/MS)法。选用1%甲酸-乙腈(体积比，3∶1)提取鸡肉、鸡肝和鸡蛋样品中的目标化合物，RAM-C18磁性分散填料进行自动分散固相萃取净化后，采用ACQUITY UPLC HSS T3柱(100 mm×2.1 mm, 1.8μm)分离，以0.01%甲酸水溶液-甲醇为流动相进行梯度分离。电喷雾离子源正离子(ESI+)模式下电离，多反应监测(MRM)扫描，内标法定量。结果表明：在0.5～200μg/L线性范围内，目标物线性关系良好，相关系数(r)均大于0.99,方法的检出限均为0.3μg/kg,定量限为1μg/kg;在低、中、高3个加标浓度下，平均回收率为77.1%～105.6%,相对标准偏差(RSD)为4.7%～18.1%。该方法前处理简单，操作便捷，灵敏度高，回收率好，适用于禽类产品中万古霉素类抗生素的快速测定，已成功应用于51件禽类样品的检测，包括14件阳性样品。     

双固相萃取/高效液相色谱-串联质谱法测定鱼类中糖肽类抗生素残留量

建立了鱼类中糖肽类抗生素万古霉素和去甲万古霉素残留量的双固相萃取/高效液相色谱-串联质谱(LC-MS/MS)检测方法。样品经0.1%甲酸水-乙腈(7:3,V/V)混合溶液提取,乙腈饱和的正己烷去脂,固相萃取柱C_(18)及PCX净化,在多反应监测(MRM)正离子模式下进行检测,使用双去氯万古霉素作为内标物,内标法定量。实验结果表明,万古霉素和去甲万古霉素在2~250 ng/mL范围内呈良好的线性关系,相关系数(r~2)大于0.99。在5,25,100μg/kg~3个添加水平下平均回收率为92.8%~96.5%,相对标准偏差为4.5%~7.0%。方法检出限(LOD)为2.0μg/kg,定量限(LOQ)为5.0μg/kg。方法适用于鱼类中糖肽类抗生素万古霉素和去甲万古霉素残留量的测定。     

高效液相色谱-串联质谱法测定乳及乳制品中大观霉素药物残留

建立了检测乳及乳制品中大观霉素药物残留量的高效液相色谱-串联质谱方法。样品直接采用0.1 mol/L乙二胺四乙酸二钠水溶液提取。挥发性离子对试剂七氟丁酸水溶液和甲醇作为流动相,增加了大观霉素的保留时间。本方法对液态奶、奶粉、酸奶、奶酪、奶油中大观霉素的测定低限均为100μg/kg。方法的线性范围为5～500 ng/mL(相关系数r0.991),回收率为75.6%～99.3%,相对标准偏差小于7.5%,能够满足乳及乳制品中大观霉素残留量的快速检测。     

毛细管电泳化学发光法测定人血清中的万古霉素和去甲万古霉素

基于万古霉素和去甲万古霉素对Ag(Ⅲ)配合物-鲁米诺化学发光体系的抑制作用,建立了毛细管电泳-化学发光法测定人血清中万古霉素和去甲万古霉素的新方法。对影响毛细管电泳分离与化学发光检测的条件进行了优化。在优化条件下,二者的线性范围均为5~80μg/m L,万古霉素的回归方程为ΔI=0.7326c+4.0738,r=0.9993,去甲万古霉素的回归方程为ΔI=0.6000c+2.000,r=0.9987,检出限均为2.5μg/m L,相对标准偏差(RSD)均小于3.8%。采用固相萃取法处理血清样品,测得万古霉素的回收率为94.5%~102.1%,去甲万古霉素的回收率为83.3%~95.8%。     

高效液相色谱-串联质谱法测定牛奶中3种糖肽类抗生素

提出了高效液相色谱-串联质谱法测定牛奶中万古霉素、去甲万古霉素和替考拉宁等3种糖肽类抗生素的含量。样品经乙腈-10%(体积分数)三氯乙酸(6+4)溶液提取,同时加入硫酸铵沉淀蛋白,以HLB固相萃取柱净化。以XBridge C18色谱柱为分离柱,以不同体积比的乙腈和乙酸(0.3+99.7)溶液的混合液为流动相进行梯度洗脱,采用电喷雾正离子源多反应监测模式检测。3种化合物的质量分数在5.00~500μg·kg-1范围内与其峰面积呈线性关系,方法的检出限(3S/N)在1.0~2.0μg·kg-1之间。在5.00,10.0,20.0μg·kg-1等3个浓度水平进行加标回收试验,回收率在70.0%~83.5%之间,测定值的相对标准偏差(n=6)在4.2%~11%之间。     

双柱净化-高效液相色谱-串联质谱法测定猪肉中7种头孢菌素残留量

建立了猪肉中7种头孢菌素类药物残留量的双柱净化-高效液相色谱-串联质谱检测方法。样品经85%乙腈水溶液提取,正己烷除脂,HLB及MAX双固相萃取小柱净化,以0.1%甲酸水溶液和乙腈为流动相,反相C₁₈色谱柱梯度洗脱分离,采用电喷雾电离正离子源(ESI+),以多反应监测(MRM)模式进行检测。7种化合物在2～100 ng/mL范围内呈良好的线性关系,相关系数(r²)大于0.99。在5～20μg/kg添加范围内,平均回收率为80.7%～112%,相对标准偏差为2.5%～8.6%。方法检出限为0.08～0.2μg/kg,定量限为0.2～0.6μg/kg。建立的方法灵敏度高、准确性好,适用于猪肉中头孢菌素类药物残留的检测。     

基于通过式固相萃取净化的液相色谱-串联质谱法测定猪肉中5种肽类抗生素

建立了一种基于免活化通过式固相萃取净化技术的液相色谱-串联质谱法(HPLC-MS/MS)用于测定猪肉中5种肽类抗生素(达托霉素、万古霉素、去甲万古霉素、维吉尼亚霉素M1、维吉尼亚霉素S1)。猪肉采用甲醇-2%甲酸(体积比为5∶2)进行提取,经免活化的Captiva EMR-Lipid固相萃取小柱净化后,以Phenomenex Kinetex F5(2.1 mm×100 mm,2.6μm)色谱柱分离,0.1%甲酸乙腈溶液和0.1%甲酸梯度洗脱。采用电喷雾离子源正离子模式扫描,多反应模式(MRM)监测目标物,内标法定量。结果表明,猪肉中达托霉素在2～200 ng/mL范围内,万古霉素及去甲万古霉素在5～500 ng/mL范围内,维吉尼亚霉素M1及维吉尼亚霉素S1在1～100 ng/mL范围内均呈良好线性关系,相关系数(r²)均大于0.99,5种肽类抗生素的检出限为3～7.5μg/kg,定量下限为5～25μg/kg。在25、50、250μg/kg 3个加标水平下的平均回收率为80.2%～102%,日内相对标准偏差(Intra-RSD)为1.3%～7.4%,日间相对标准偏...     

LixZryOz三元化合物的制备及表征

采用高温固相法制备了4种高纯度晶相组成的LixZryOz三元化合物,研究了焙烧温度、时间、反应物的种类和初始反应物物质的量比对产物组成的影响,进一步用XRD、SEM及BET分析方法对产物的晶相结构、表面形貌及比表面积进行了表征.实验结果表明,Li2CO3与ZrO2在适当条件下可以合成得到单斜相Li3ZrO3;以LiOH替代Li2CO3,在适当条件下可以分别合成得到四方相Li2ZrO3和三斜/单斜相Li6Zr2O7;进一步以Zr(NO3)4·5H2O代替Zr02,可将单斜相Li6Zr2O7的制备时间由96 h缩短至24 h.SEM照片显示产物硬团聚明显,粒径分布在1～10μm间,BET分析表明样品比表面积处于1.0～9.0 m2·g-1间分布,反应过程中锂的过量以及长时间高温焙烧是引起产物粒径长大和产生硬团聚的主要原因.     

Synthesis of chlorobis/β-diketonato/oxotechnetium/V/ and tris/β-diketonato/technetium/III/ complexes

Chlorobis/-diketonato/ oxotechnetium/V/ complexes [TcOCl/-dik/₂, -diketone=acetylacetone, benzoylacetone and dibenzoylmethane] were newly synthesized using macroamount of⁹⁹Tc. These complexes were further separated into geometrical isomers. Furthermore, an improvement of the yields for the syntheses of tris/-dike-tonato/technetium/III/ complexes [Tc/-dik/₃, -diketone=acetylacetone, benzoylacetone and 2-thenoyltrifluoroacetone] was examined using Tc/III/-thiourea complexes as a starting material.     

Solvent extraction separation of In/III/-Tl/III/ and Hg/II/-Cd/II/-Co/II/ with sulphoxides

Solvent extraction studies have been made on some metals: In/III/-Tl/III/ and Hg/II/-Cd/II/-Co/II/, from ammonium thiocyanate solutions by dialkyl sulphoxides. Separation of these metals from one another can be achieved by suitable choice of the extracted conditions. The nature of the extractable metal species has been elucidated.     

LixNi0.8-yCo0.2ZnyOp的合成及电化学性能研究

A series of single-phase Li_xNi_0.8-yCo_0.2Zn_yO_p(0.96 ≤x≤ 1.10， 0 ≤y≤ 0.05， 2 ≤p≤ 2(1+y) ) (different in the y values) were synthesized by a two-step solid state reaction method， in which LiOH·H₂O， Zn-doped spherical Ni(OH)₂ and Co₂O₃ were used as the precursors. The ICP-AES analyses proved that the Zn-doped compounds synthesized had the nonstoichiometric form. The results of the XRD， SEM identified that the uniform particles of the as-prepared materials having a good layered structure were fine， narrowly distributed and well crystallized. The electrochemical performance test was carried out and the results showed that the as-prepared Zn-doped materials had not only a high capacity， but also a better cycling stability characterization than the un-doped one. The Li_1.06Ni_0.75Co_0.22Zn_0.03O_2.03 material has an initial reversible capacity as high as 160.5mAh·g^-1; and a first discharge efficiency 89.2%， and exhibits satisfactory cyclic stability with 90% retainable capacity after 50 cycles.     

Carbon black and propylene oxidation over Ru/CoxMgyAl2Oz catalysts

The effects of Co_xMg_yAl₂O_z mixed oxides composition and ruthenium addition on the oxidation of propylene and carbon black (CB) were investigated. Different reactive cobalt and ruthenium oxide species were formed following calcination at 600 °C. The addition of ruthenium was beneficial for the CB oxidation under “loose contact” conditions and for propylene oxidation when the cobalt content was intermediate to low. The calculated activation energy for CB oxidation was decreased from 151 kJ mol⁻¹ for the uncatalyzed reaction to 111 kJ mol⁻¹ over the best catalyst.     

Synthesis and properties of the Co7Se8−xSx and Ni7Se8−xSx solid solutions

We report the synthesis and elementary properties of the Co₇Se_8−xS_x (x=0-8) and Ni₇Se_8−xS_x (x=0-7) solid solutions. Both systems form a NiAs-type structure with metal vacancies. In general, the lattice parameters decrease with increasing x, but in the Ni₇Se_8−xS_x system c increases on going from x=5 to 7. Magnetic susceptibility measurements show that all samples exhibit temperature-independent paramagnetism from 25-250 K. Samples within the Co₇Se_8−xS_x system, as well as Ni₇Se₈ and Ni₇SeS₇, were found to be poor metals with resistivities of ∼0.20 and ∼0.06 mΩ cm at 300 K, respectively. The Sommerfeld constant (γ) was determined from specific heat measurements to be ∼13 mJ/mol_CoK² and ∼7 mJ/mol_NiK² for Co₇Se_8−xS_x and Ni₇Se_8−xS_x, respectively.     

Electronic and magnetic properties of LaNi1−xCoxO3, LaCo1−xFexO3 and LaNi1−xFexO3

LaNi_1?xCo_xO₃ shows itinerant d-electron behavior similar to LaNiO₃ up to x = 0.5. In the range 0.5 < x < 1.0, the cobalt spin state equilibrium is markedly affected; the localized-itinerant electron transition of LaCoO₃ is not seen when x < 0.95. In LaCo_1?xFe_xO₃, itinerancy of d-electrons decreases with increase in x and the compositions with x > 0.5 are similar to LaFeO₃. If x > 0.1, the localized-itinerant electron transition is not seen and the cobalt spin state equilibrium is considerably altered. In LaNi_1?xFe_xO₃, itinerancy decreases with increase in x. These observations can be satisfactorily explained in terms of Goodenough's energy band schemes.     

Separation of Th/IV/ and U/VI/ by extraction chromatography

Application of extraction chromatographic technique to the analytical separation of Th/IV/ and U/VI/ has been investigated. The stationary phase was a macroporous resin Amberlite XE-270 impregnated with undiluted trin-n-butylphosphate /TBP/ and the mobile phase was either 5.OM HNO₃ or 6M HCl. Separation of traces of Th/IV/ from large quantities of U/VI/ was achieved on a laboratory column by elution of the absorbed Th/IV/ with 6M HCl.     

Rate of reactions between D2O and CaxAlyOz

The rate of the reaction between D₂O and the calcium aluminum oxides Ca₃Al₂O₆, Ca₅Al₆O₁₄, CaAl₂O₄, and CaAl₄O₇ was investigated by on-line neutron diffraction powder methods at temperatures from room temperature to 100°C. The rate of the reaction increases with increasing calcium content of the compounds and with increasing temperature for each of the compounds. The crystallographic stable hydrate Ca₃Al₂(OD)₁₂ is obtained from CaAl₄O₇ and CaAl₂O₄ at temperatures above 63°C, from Ca₅Al₆O₁₄ at temperatures above 49°C, and from Ca₃Al₂O₆ at temperatures as low as 7°C.