用环炉技术监测大气中微量汞

环炉法是一种能进行现场监测的简便快速分析方法。Thabet等曾研究了以盐酸羟胺还原Hg~(2+)成元素汞的环炉比色法,但灵敏度和选择性都不很高。笔者曾报告了以溶剂萃取富集、用四碘汞铜环比色测定水中痕量汞的方法,灵敏度较高,但冲洗液对环炉柱体腐蚀较甚,需要改进。 West等研究的“不渗透栅栏环技     

Characters of the Plateau of Methanol Increment in Frontal Analysis in Reversed Phase Liquid Chromatography

With insulin methanol-water,and the ion-pairing agent,hydrochloric acid and trifluroacetic acid(TEA),the character of the first plateau(FP)on the elution curve of frontal analysis in reversed phase liquid chromatography(RPLC)was investigated by on-line UV-spectrometry and identified with nuclear magnetic resonance(NMR) spectrometry and mass spectrometry.The profile of the FP is the same as that of a usual elution curve of methanol in frontal analysis(FA).When the insulin concentration was limited to a certain range,the height of the FP was found to be proportional to the insulin concentration in mobile phase and its length companying to shorten,The FP profile on the intersection of two tangents reflects the components of the microstructure in the depth direction of the bonded stationary phase layer and the desorption dynamics of the displaced components.The displaced methanol was quantitatively determined by NMR and on-line UV spectrometries.TFA with high UV absorbance can not be used as an ionpairing agent for the investigation of the FP in RPLC,but if can be used as a good marker to investigate the complicated transfer process of components in the stationary phase in RPLC.A stoichiometric displacement process between solute and solvent was proved to be valid in both usual and FA in RPLC.From the point of view of dynamics of mass transfer, the solutes can only contact to the surface of stationary phase in usual RPLC,while solute can penetrate into it in FA of RPLC.The solvation of insulin in methanol and water solution as an example indicating the usage of the FP in the FA was also investigated in this paper.     

线性参数logI对反相液相色谱中的非极性小分子溶质体系的表征

从理论上阐明了计量置换平衡常数的对数ｌｏｇＫａ对液相色谱中计量置换保留模型的线性参数ｌｏｇＩ起着主导作用。ｌｏｇＩ表示溶质对固定相的亲合势，且具有热力学平衡常数的性质。     

Retention model of protein for mixedmode interaction mechanism in ion exchange and hydrophobic interaction chromatography

A unified retention equation of proteins was proved to be valid for a mixed-mode interaction mechanism in ion exchange chromatography (IEC) and hydrophobia interaction chro-matography (HIC). The reason to form a "U" shape retention curve of proteins hi both HIC and IEC was explained and the concentration range of the strongest elution ability for the mobile phase was determined with this equation. The parameters in this equation could be used to characterize the difference for either HIC or IEC adsorbents and the changes in the molecular conformation of proteins. With the parameters in this equation, the contributions of salt and water in the mobile phase to the protein retention in HIC and IEC were discussed, respectively. In addition, the comparison between the unified equation and Melander' s three-parameter equation for mixed-mode interaction chromatography was also investigated and better results were obtained in former equation.     

重组人粒细胞集落刺激因子的摇瓶发酵研究

目的 优化重组大肠杆菌生产人粒细胞集落刺激因子摇瓶发酵工艺条件。方法 利用摇瓶系统地考查rhG-CSF茵株培养温度、诱导时机、pH值、溶氧、种子茵龄、接种量等工艺条件，选择出最佳的摇瓶培养条件。结果 最佳条件为：培养温度30℃；初始pH值在7．0～7．2；装液量20％；摇床转速180r／min；种子菌龄在A600为1．0～1．5时接种，并在对数生长前期(A600=1．0)时诱导4h。在此优化的培养条件下，在摇瓶中使用优化后的M9培养基时，rhG-CSF的表达量占茵体总蛋白的36．5％，光密度达5．85。结论 构建的rhG-CSF工程菌发酵的稳定性和重复性良好，可作为rhp-CSF的大规模生产提供可靠的放大依据。     

人IFN-γ在大肠杆菌中高效表达和色谱复性研究

从健康人外周血分离单核细胞，经LPS刺激后提取总RNA，用RT—PCR扩增hIFN-γ的cD—NA。将扩增产物克隆后进行序列分析证明，克隆的hIFN-γcDNA除存在2个序列多态性位点外，与天然的干扰素氨基酸序列完全一致。利用温控表达系统在大肠杆菌中实现了hIFN-γ的高效表达，表达的目的蛋白可占茵体总蛋白的55％。用5L和50L发酵罐放量生产的产物，经高效疏水色谱HPHIC直接复性和纯化得到了重组hIFN-γ纯品，其比活性与天然蛋白相近．     

两个计算二组分液-固吸附表面过剩的经验公式

以文献发表的67组实验数据依据,研究了用两个经验公式计算二组分全浓度范围内液—固吸附的表面过剩值。依据两个经验方程,用微机对这些实验数据进行拟合,求出对应于每个吸附体系中经验方程的一系列参数值和非线性相关系数r。由对这些体系中r值大小的统计结果表明,在其规定范围内,用这两个经验方程计算表面过剩值是满意的。     

用参数Z表征疏水色谱中脲变α-糜蛋白酶及其折叠中间体的分子构象变化

目的用参数Z表征疏水色谱中脲变α-糜蛋白酶(α-Chy)及其折叠中间体的分子构象变化。方法用疏水色谱法对不同脲变条件下的α-Chy进行分离,对收集的不同馏分用基质辅助激光解吸附离子化飞行时间质谱(HPHIC-MALDI-TOF-MS)进行检测,并用紫外和荧光光谱对其分子构象变化进行了验证。结果确认了脲变α-Chy中仅有一个稳定的折叠中间体存在,发现二者的Z值均随脲浓度的增加而减小。在脲浓度范围为0~3.0 mol.L-1时,α-Chy折叠中间体的Z值远小于天然α-Chy的Z值,而脲浓度为4.0 mol.L-1和5.0 mol.L-1时,折叠中间体的Z值稍大于天然α-Chy的Z值。结论α-Chy折叠中间体的分子构象随脲浓度改变基本呈连续性变化,而天然α-Chy的分子构象随脲浓度呈不连续性变化。进一步发现α-Chy的Z值与其复性回收率之间存在着相似的变化规律。中间体的保留机理服从计量置换保留理论(SDT-R),且得到的参数Z可用来表征天然α-Chy和其折叠中间体的分子构象变化。     

用于变性蛋白质复性及同时纯化的简易型色谱柱的研制及其应用

研制出一种简易型色谱柱并通过装填大颗粒的疏水色谱填料对色谱柱的性能进行了考察,该柱的外形和操作如同传统的液相色谱柱,但它却在生物大分子分离方面有着和高效液相色谱相似的分辨率。另外,只要给该柱装填合适的固定相,比如疏水相互作用色谱固定相,便可用于蛋白质的复性及同时纯化。实验考察了该色谱柱的结构、操作和性能,包括柱压、柱寿命及对蛋白质的分辨率等。以溶菌酶为模型蛋白质,实验测得其在初始浓度为50.0 g/L时的质量回收率和活性回收率分别为(96.6±1.3)%和(101.1±6.0)%。这种简易型色谱柱价格低廉