液相色谱-质谱联用技术测定无糖食品中果糖、葡萄糖、蔗糖、麦芽糖和乳糖

建立了无糖食品中葡萄糖、果糖、蔗糖、麦芽糖、乳糖的高效液相色谱-串联四极杆质谱联用测定方法.本方法以水提取样品,以Waters Carbohydrate Analysis柱(300 mm×3.9 mm, 10 μm)分离,流动相为水-乙腈(15∶ 85, V/V),电喷雾负离子MRM模式检测.方法的检出限为0.1 g/kg;线性范围为2.5～125.0 mg/L;加标回收率为86.2%～97.7%;相对标准偏差为3.1%～8.7%.     

1,3,5,7-四乙酰基-1,3,5,7-四氮杂环辛烷合成反应中间体的制备分离

1,3,5,7-四乙酰基-1,3,5,7-四氮杂环辛烷(TAT)是高能炸药奥克托今(HMX)重要的合成反应前体之一,1,5-二乙酰基-1,3,5,7-四氮杂环辛烷(DAPT)醋酐酰解法和乙腈甲醛小分子缩合法均能制备得到TAT.采用半制备高效液相色谱制备分离了上述两种制备方法反应原液中的六种中间体,分别是1-乙酰氧甲基-3,5,7-三乙酰基-1,3,5,7-四氮杂环辛烷、1,3,5-三乙酰基-1,3,5,7-四氮杂环辛烷、1-乙酰氧甲基-3,5,7-三乙酰基-1,3,5,7-四氮杂环辛烷、N,N’-亚甲基二乙酰胺、三乙酰胺二亚甲基三胺和四乙酰胺三亚甲基四胺,为反应机理研究提供了有力的证据.DAPT醋酐酰解法反应原液样品的最佳制备色谱条件为:正相硅胶柱(20 mm×250 mm,10～20μm),流动相:V(乙腈)∶V(甲醇)=95∶5,流速为10 mL·min-1,检测波长为215 nm,进样量为1 mL,样品浓度30 mg/mL.乙腈甲醛小分子缩合法反应原液样品的最佳制备色谱条件为:正相硅胶柱(20 mm×250 mm,10～20μm),流动相:V(乙腈)∶V(水)=90∶10,流速为10 mL·min-1,检测波长为215 nm,进样量为1 mL,样品浓度30 mg/mL.制备得到的中间体经HPLC分析知纯度均在97%以上,可直接作为结构鉴定的标准样品.     

柱切换高效液相色谱法测定人血浆中布洛芬对映体浓度

建立了柱切换高效液相色谱法测定人血浆中布洛芬对映体浓度的方法。以对溴苯甲酸为内标,样品经醋酸钠缓冲液酸化后,用V(正己烷)∶V(异丙醇)=95∶5萃取。以Chiralcel OJ-H柱(Daicel Chemicals,250mm×4.6mm,5μm)为分析柱,UltimateTM SiO柱(50mm×4.6mm,5μm)为预处理柱;流动相为V(正己烷)∶V(异丙醇)∶V(三氟醋酸)=96.5∶3.5∶0.1,流速为0.5mL/min;预处理流动相为V(正己烷)∶V(异丙醇)=99.5∶1,流速为1mL/min;柱切换时间为1.70~4.09min;紫外检测波长为230nm。布洛芬消旋体和S-( )-布洛芬标准曲线线性范围分别为0.21~20mg/L和0.10~10mg/L;日内RSD小于6.5%,日间RSD小于6.1%;方法回收率为93.3%~107.1%,萃取回收率为80.0%~86.6%。本法简便、准确,重现性好,可用于布洛芬对映体人体药代动力学研究。     

接枝中空纤维膜过滤-液相色谱/串联质谱法检测血浆中盐酸克伦特罗

建立了接枝改性的中空纤维膜过滤法净化处理-液相色谱-串联质谱法(LC-MS/MS)测定血浆中痕量盐酸克伦特罗的方法。血浆样品经改性中空纤维膜的过滤,通过膜上接枝的离子交换基团的吸附作用和膜孔的超滤作用去除其中的磷脂和蛋白质,消除了基质效应,提高了LC-MS/MS检测盐酸克伦特罗的灵敏度。色谱条件为:色谱柱采用Venusil MP C18(2.1×50 mm,3μm,10 nm),流动相为乙腈/0.1%甲酸水溶液(15:85,V/V),流速为200μL/min,柱温30℃,进样量5μL。质谱模式为电喷雾电离正模式。在1~100 ng/m L范围内,线性关系良好;检出限为0.21 ng/m L,回收率在90%~105%之间,RSD为3.8%~9.1%。方法适合血浆样品中痕量盐酸克伦特罗的检测。     

高效液相色谱柱后衍生测定鸡组织中甲基盐霉素残留量

建立了鸡组织中甲基盐霉素的高效液相色谱柱后衍生化分析方法.样品经异辛烷提取,离心后上层有机相过硅胶固相萃取小柱,洗脱液浓缩后用V(甲醇)∶ V(水)=90∶ 10混合液溶解.采用Inertsil ODS-3 C18柱,以V(甲醇): V(乙酸)∶ V(水)=94∶ 3∶ 3为流动相,香草醛为衍生剂进行高效液相色谱柱后衍生分析,520 nm检测,外标法定量.方法检出限为6 μg/kg; 定量限为20 μg/kg; 添加浓度在20～1800 μg/kg范围内,平均添加回收率为76.4%～93.1%; 批内相对标准偏差(RSD)在2.6%～8.9%之间; 批间相对标准偏差(RSD)在4.7%～9.7%之间.样品浓度在0.07～10.0 mg/L范围内与峰面积呈良好的线性关系,r>0.9993.     

反相高效液相色谱负峰测定法研究以及酮类的测定

研究了反相液相色谱中负峰现象及产生的原理,应用计量置换作用原理解释了样品在色谱柱中的计量置换保留行为;应用负峰法测试了甲基脂肪酮各组分的含量.本研究采用Agilent C18色谱柱(150 mm×4.6 mm, 5 μm), 流动相为V(甲醇)∶ V(水, 含0.01 mmol/L磺基水杨酸)=60∶ 40, 紫外检测器(λsig=310 nm, λref=275 nm). 本方法简便,线性相关系数r均大于0.9993; 甲基酮的定量下限为0.041 μg; 相对标准偏差为0.52%～0.80%.     

凝胶渗透色谱-高效液相色谱-串联质谱法同时测定烟草中3种抑芽剂残留

建立了用凝胶渗透色谱净化-液相色谱-串联质谱分析烟草中3种抑芽剂残留的方法。卷烟中的待测抑芽剂组分用V(乙酸乙酯)∶V(环己烷)=1∶1超声提取后通过凝胶渗透色谱净化;凝胶色谱柱为Biobeads S-X3玻璃柱(50 g,400 mm×25 mm),流动相为V(乙酸乙酯)∶V(环己烷)=1∶1溶液,流速5 mL/min;收集第10~25 min流出的液体用液相色谱色谱-三重四极杆串联质谱仪测定。在0.5~100 ng/mL的质量浓度范围内,各种抑芽剂标准溶液的线性相关系数均大于0.99。在样品中添加3种抑芽剂(添加水平为5,20,100μg/kg)的混合标准溶液,平均回收率在86.2%~108.4%之间,3种抑芽剂的RSD在1.1%~7.5%之间;方法的检测限在0.01~0.06μg/kg之间。     

高效液相色谱-荧光检测法分析麦类中麦角克列斯汀碱

提出了一种采用高效液相色谱-荧光检测法(HPLC-FLD)测定麦类样品中麦角克列斯汀碱的方法。麦类样品经V(乙腈)∶V(0.1 mol/L乙酸铵缓冲溶液)=1∶4提取,以C18小柱净化,C18色谱柱(4.6×250 mm,5μm)分离,V(水)∶V(乙腈)=3∶2作流动相,流速1.0 mL/min,以HPLC-FLD定量测定。标准工作溶液浓度在1.0~50.0μg/L范围内,与峰面积成良好的线性关系,线性相关系数0.9999,样品在10.0、50.0、250.0μg/kg添加水平的回收率为76%~85%,相对标准偏差(RSD)为6.6%~8.8%(n=8),方法检测限为5.0μg/kg(S/N10)。     

中空纤维离心超滤-高效凝胶排阻色谱法测定青霉素V钾中蛋白杂质

建立了一种采用中空纤维离心超滤(HFCF-UF)-高效凝胶排阻色谱法(HPSEC)对青霉素V钾中的残留蛋白进行检测的方法。样品用HFCF-UF进行富集,采用HPSEC进行分析,色谱柱为TSK gel Super SW2000凝胶色谱柱(300×4.6mm,4μm),流动相为0.06mol/L NaCl-0.02mol/L NaH_2PO_4(pH=7.0),流速为0.3mL/min,紫外检测波长为220nm,柱温为室温。对照品牛血清白蛋白(BSA)在1.0~100.0μg/mL内线性关系良好(R2=0.999),回收率均大于87%,检测限为3.03ng/mL,经HFCF-UF富集处理后,富集倍数(EF)高达99倍。结果表明,该方法操作简便、结果准确、灵敏度高,为同类药物中的大分子蛋白检测提供了有效手段。     

加速溶剂萃取-高效液相色谱法测定土壤中咪唑乙烟酸残留量

建立了加速溶剂萃取-高效液相色谱法测定土壤中咪唑乙烟酸除草剂残留量的检测方法.加标土壤样品以V(甲醇)∶V(冰乙酸)＝5∶1作提取剂,在温度50 ℃,压力9 MPa下静态萃取10 min,提取物用高效液相色谱二极管阵列检测器进行分析.色谱柱为ODS柱,流动相为V(甲醇)∶V(水)∶V(冰乙酸)＝50∶46∶4,流量: 1 mL/min;检测波长: 254 nm.结果表明: 1和10 μg/g的加标回收率分别为90%和86%,相对标准偏差分别为4.1%和4.5%,检出限可达0.006 μg/g.     

Hollow-Fiber Ultrafiltration then Centrifugation for LC Analysis of Water-Soluble Sucrose in a Water-Soluble High-Molecular-Mass Gel Matrix

A novel, simple, and economic method, hollow-fiber ultrafiltration followed by centrifugation, has been developed for separation of viscid substances with similar properties except for different molecular weight. The experimental assembly needed only a U-shaped hollow fiber containing the sample solution with both ends of the fiber connected to two syringe needles. Ultrafiltration was performed by the action of centrifugal force. Concentration polarization was overcome and no phase transition occurred. Satisfactory recovery was achieved.     

Analysis of constant permeate flow filtration using dead-end hollow fiber membranes

Dead-end filtration of colloids using hollow fibers has been analysed theoretically and experimentally. A mathematical model for constant flux filtration using dead-end hollow fiber membranes has been developed by combining the Hagen–Poiseuille equation, the (standard) filtration equation, and cake filtration theory of Petsev et al. [D.N. Petsev, V.M. Starov, I.B. Ivanov, Concentrated dispersions of charged colloidal particles: sedimentation, ultrafiltration and diffusion, Colloid Surf. A: Physicochem. Eng. Aspects, 81 (1993) 65–81.] to describe the time dependence of the filtration behavior of hollow fiber membranes experiencing particle deposition on their surface. Instead of using traditional constitutive equations, the resistance of the cake layer formed by the deposited colloids has been directly correlated to the cake structure. This structure is determined by application of a force balance on a particle in the cake layer combined with the assumption that an electrostatically stable cake layer of mono-sized particles would be ordered in a regular packing geometry of minimum energy. The developed model has been used to identify the relationship between the filtration behavior of the hollow fiber membrane and the particle properties, fiber size, and imposed average flux. Filtration experiments using polystyrene latex particles of relatively narrow size distribution with a single dead-end hollow fiber membrane demonstrate good consistency between experimental results and model prediction. The developed model has been used to simulate the distribution of the cake resistance, transmembrane pressure, and flux along the hollow fiber membrane and used to assess the effect of fiber size, particle size, zeta potential, and the average imposed flux on the suction pressure-time profiles, flux, and cake resistance distributions. These results provide new insights into the filtration behavior of the hollow fiber membrane under constant flux conditions.     

Synthesis and characterization of titania hollow fiber and its application to the microextraction of trace metals

A titania hollow fiber membrane was successfully synthesized in a macro range via a template method coupled with a sol-gel process. Thermal gravimetric and differential thermal analysis (TG-DTA) was employed to study the effect of heat treatment on the synthesized hollow fiber, and the crystal forms of the titania hollow fiber membranes at different temperatures were studied by X-ray diffraction (XRD). The pore structure of the prepared titania hollow fiber was characterized by scanning electron micrograph (SEM) and nitrogen adsorption/desorption measurements. The prepared titania hollow fiber membrane was explored as a new adsorption material for trace metals for the first time and a new method of titania hollow fiber membrane solid phase microextraction (MSPME) online coupled to inductively coupled plasma mass spectrometry (ICP-MS) was developed for the determination of trace amount of Cd, Co, V and Ni in human serum samples. In order to validate the developed method, two certified reference materials of NIES.No.10-b rice flour and BCR No.184 bovine muscle were analyzed and the determined values were in good agreement with the certified values.     

同质编织管增强型聚丙烯腈中空纤维膜研究

利用二维编织技术将聚丙烯腈(PAN)纤维编织成中空编织管,以聚丙烯腈为成膜聚合物,以聚乙二醇为成孔剂,配制铸膜液,采用同心圆纺丝法制备同质编织管增强型聚丙烯腈中空纤维膜.研究结果表明,所得同质编织管增强型聚丙烯腈中空纤维膜的表面分离层具有类似于非对称膜的结构,铸膜液可渗入编织管纤维束中;随着编织管编织节距的增大,同质编织管增强型聚丙烯腈中空纤维膜表面分离层厚度减小,同时膜的平均孔径增大,膜的纯水通量随之增大;铸膜液渗入编织管纤维束的现象未影响膜的通透性能;编织管的断裂强度最大可达100 MPa以上.通过水浴振荡、超声波水浴振荡及等力拉伸3种方法测试了同质编织管增强型中空纤维膜和异质编织管增强型中空纤维膜中编织管与表面分离层之间的界面结合性能,结果表明前者的界面结合性能优于后者.     

BPA transfer rate increase using molecular imprinted polyethersulfone hollow fiber membrane

Bisphenol A (BPA) imprinted polyethersulfone (PES) hollow fiber membrane was spun using a dry–wet spinning method, the membrane was then prepared as a filter with an effective area of 200 cm². The hollow fiber filter was employed to study the BPA transport behavior. The transport ability of the prepared hollow fiber membrane was measured using 100 μmol/l BPA aqueous solutions at a flow flux of 50 and 75 ml/min, respectively. The BPA transfer rate increased for the imprinted hollow fiber membranes due to the larger amount of binding sites, comparing with the non-imprinted one. In the present study, hollow fiber membrane and the molecular imprinting technique were combined for advanced separation and the data suggested that small molecules could transfer in the direction opposite to the concentration gradient due to different pH.     

Self-assembly of inner skin hollow fiber polyelectrolyte multilayer membranes by a dynamic negative pressure layer-by-layer technique

In the past studies, electrostatic layer-by-layer (LbL) adsorption of oppositely charged polyelectrolytes has proven to be a promising method for the preparation of polyelectrolyte multilayer membranes (PEMMs). Till now, this method was mainly used to assemble flat sheet and tubular membranes. Since hollow fiber membrane has some advantages such as high-packing density, self-contained mechanical support and hence the consequent economical superiority, this study therefore seeked to assemble inner skin hollow fiber PEMMs by using a dynamic LbL adsorption technique. The assembly process was successfully accomplished by alternatively dynamically filtrating polyacrylic acid (PAA) and polyethyleneimine (PEI) on a hydrolyzed hollow fiber polyacrylonitrile (PAN) membrane under a negative pressure condition. In the case of pervaporation separation of 95 wt.% ethanol–water mixture (50 °C), the membrane obtained with only 4.5 and 6.5 bilayers had separation factor of 245 and 1338 while the permeate fluxes were 290 and 120 g/(m² h), respectively. The pervaporation separation behavior of various alcohol/water mixtures with the alcohols being t-butanol, 2-propanol and ethanol were also investigated. Finally, scanning electron microscopy and atomic force microscopy clearly confirms a uniform and defect-free layer formed on the inner surface of hollow fiber support. Since different polyelectrolyte pairs could be used to assemble PEMMs for different uses, it was expected that the dynamic negative pressure LbL adsorption technique could also potentially be used to prepare many types of PEMMs in other fields.     

聚全氟乙丙烯中空纤维膜研究

以聚全氟乙丙烯(FEP)为成膜聚合物,复合无机粒子为成孔剂,邻苯二甲酸二辛酯(DOP)为稀释剂,采用熔融纺丝工艺制备得到FEP中空纤维膜.分析和讨论了不同成膜体系对FEP中空纤维膜热性能、动态力学性能和力学性能的影响,并对膜的纯水通量和孔径分布进行表征.用扫描电子显微镜(SEM)观察了膜的横断面和表面形貌.结果表明,所得FEP中空纤维膜为由溶出微孔和界面微孔组成的海绵状孔结构.随着成孔剂含量的增加,成孔剂在成膜体系中分散程度变差,容易发生团聚,最终导致膜孔径变大,孔径分布变宽.成孔剂和稀释剂对FEP中空纤维膜的热性能和动态力学性能影响较小.当FEP含量增加到70 wt％时,膜表面容易形成一层致密层,降低了膜的通透性.     

Electrokinetic migration of acidic drugs across a supported liquid membrane

Electrokinetic cross membrane extraction of acidic drugs was demonstrated for the first time. The acidic drugs were extracted from an alkaline aqueous donor solution (300 microl), through a thin supported liquid membrane of 1-heptanol sustained in the pores of the wall of a porous hollow fiber, and into an aqueous alkaline acceptor solution (30 microl) present inside the lumen of the hollow fiber by the application of a d.c. electrical potential. The negative electrode was placed in the donor solution, and the positive electrode was placed in the acceptor solution. Optimal extractions were accomplished with 1-heptanol as the supported liquid membrane, with 50 V as the driving force, and with pH 12.0 in both the donor and acceptor solutions, respectively (NaOH). Equilibrium extraction conditions were obtained after 5 min of operation with the whole assembly agitated at 1200 rpm. Eleven different acidic drugs were extracted with recovery values between 8 and 100%, and initial data supported that electrokinetic cross membrane extraction provided repeatable data and linear response between original donor concentration and final acceptor concentration of the acidic model compounds.     

填充液压力对聚醚砜中空纤维膜微结构和性能的影响

研究了聚醚砜／二甲基亚砜(PEs／DMS0)体系中填充液压力的变化对PES中空纤维结构及性能的影响。结果表明,随着填充液压力的增大,中空纤维膜的水通量增大,轴向取向度下降。为纺制具有合适性能的中空纤维膜提供参考。     

熔纺聚氨酯系中空纤维膜的结构与性能

将聚氨酯/聚偏氟乙烯/聚乙二醇(PU/PVDF/PEG)熔融共混纺丝制得中空纤维膜,对纤维膜的微孔结构与性能进行研究,分析影响其水通量衰减的因素。结果表明:所得纤维膜具有界面及非界面微孔结构;随着水通量工作环境的变化,膜孔结构发生相应变化,表现出压力及温度响应性能;而经热处理后,所得膜部分微孔闭合,水通量下降;随测试时间延长,膜结构趋于致密化,水通量衰减。