薄层色谱法分析2-丙烯酰胺基-2-甲基丙烷磺酸

应用薄层色谱法对工业品２ 丙烯酰胺基 ２ 甲基丙烷磺酸（简称ＡＭＰＳ）进行了分析,以硅胶ＧＦ２５４作为吸附剂,从几种溶剂系统中优选了Ｖ（苯）∶Ｖ（甲醇）＝２∶１溶液作为展开剂,用２５４ｎｍ紫外分析仪检测展开后的样品斑点。实验表明：ＡＭＰＳ的Ｒｆ为０３６,而其主要杂质丙烯酰胺（ＡＭ）的Ｒｆ为０．６４;ＡＭＰＳ的最小检出限为５μｇ,展开时间约为２５ｍｉｎ。方法简便、快速、重现性好,有利于在生产过程中快速分析ＡＭＰＳ及其所含杂质,从而指导对ＡＭＰＳ的纯化处理。     

青络锗和青络铜对清除氧自由基的研究

以邻苯三酚（ＰＡ）为氧自由基释放剂,以四氮唑蓝（ＮＢＴ）为显色剂,利用样品对ＰＡ自身氧化释放氧自由基的抑制作用,对样品清除自由基能力进行比色测定,效果满意。     

在线单柱二维液相色谱法快速纯化牛胰腺中细胞色素C

用二维（弱阳,疏水）色谱柱首次完成了在线单柱二维液相色谱法快速纯化牛胰腺中的细胞色素C.在将牛胰腺粗提液进样到该二维色谱柱后,在弱阳离子交换模式下,以梯度洗脱方式进行一维色谱分离,并将分离得到的细胞色素C样品液收集到色谱仪的附加样品储液管内.然后将储液管中样品液全部排出,并二次进样到同一根二维色谱柱中,与此同时也完成了对该样品液的缓冲溶液交换,按疏水色谱（HIC）分离模式进行分离.最终对细胞色素C完成了第二维的HIC纯化.上述全部操作均为在线,在一具有正压的封闭体系中进行并可在52分钟内完成.细胞色素C的最终产品纯度高达94.7%（RSD=1.91%）,质量回收率为80.5%（RSD=2.20%）.预计此在线单柱二维液相色谱法也可能用于牛胰腺中其他功能蛋白的快速纯化,并可能将其放大到制备和生产规模.     

OPA柱前衍生反相高效液相色谱法测定氨基酸含量

建立了邻苯二甲醛（ＯＰＡ）手动柱前衍生反相高效液相色谱法测定样品中氨基酸含量的方法。以邻苯二甲醛（ＯＰＡ）／３－巯基丙酸（３－ＭＰＡ）为衍生试剂进行衍生,ＯＤＳ柱分离,３４０ｎｍ检测,在４０ｍｉｎ内１８种氨基酸全部得到基线分离。测定牛血清白蛋白（ＢＳＡ）的氨基酸组成和小鼠血清中的游离氨基酸,取得满意的结果。     

流动注射荧光法测定脱氧核糖核酸

合成了新配体２－苯基（４－氯）咪唑〔ｆ〕邻菲咯啉（简称ＰＩＰ（Ⅱ）,并合成络合物Ｒｕ（ｂｐｙ）２ＰＩＰ（Ⅱ）,研究了该络合物与ＤＮＡ作用的荧光光谱,观察到５９０ｎｍ（λｅｘ＝４６０ｎｍ）处产生很强的荧光峰,采用流动注射法测定ＤＮＡ,该方法简便快速,灵敏度高。对合成样品测定获得满意结果。     

荧光分光光度法直接测定炎痢停片中的甲氧苄氨嘧啶和氟哌酸

应用荧光分光光度法通过更换溶剂,不经分离同时测定了炎痢停片中甲氧苄氨嘧啶（ＴＭＰ）和氟哌酸的含量。水相中直接测定了氟哌酸含量,乙醇相中测定ＴＭＰ时,引入光度分析中的Ｈ－点标准加入法求得ＴＭＰ的含量。该方法平均回收率：ＴＭＰ为１００．４４％（ＲＳＤ＝１．７６％,ｎ＝５）。氟哌酸为９９．９６％（ＲＳＤ＝１．６２％,ｎ＝５）。此法可作为样品的检测方法,也可应用于生产质量控制和药物代谢研究。     

无机基质疏水作用色谱填料的研制及扩试

以无机基质可控孔径玻璃（ＣＰＧ）和大孔硅胶为基质、聚乙二醇（ＰＥＧ１０００）为配基,利用改进的合成方法制备了疏水作用色谱（ＨＩＣ）填料,并进行了１５０ｇ／批的扩大试验,用标准蛋白为样品进行了色谱行为的研究。结果表明,此类填料对蛋白质的分离性能良好,对胰蛋白酶的活性回收率大于９５％。     

逆最小二乘法—导数谱同时测定锌,镉,汞和铅

本文研究了在碱性介质中，ＣＰＢ存在下，ｍｅｓｏ－四（４－三甲铵基苯）卟啉与Ｚｎ（Ⅱ），Ｃｄ（Ⅱ），Ｈｇ（Ⅱ）和Ｐｂ（Ⅱ）络合物的导数光谱，提出了应用逆最小二乘法（或称ＣＰＡ－矩阵法）原理对导数光谱进行解释，同时测定四组分的方法。应用本法对合成样品和水进行分析，结果满意。     

毛细管区带电泳分析阿片受体和抗独特型抗羟甲芬太尼抗体

应用毛细管区带电泳（ＣＺＥ）分析测定阿片受体、抗独特型抗羟甲芬太尼抗体等生物大分子样品。熔融石英毛细管柱为６０ｃｍ×１００μｍｉ．ｄ．（从进样到检测器长度为５０ｃｍ）,以硼砂－氢氧化钾为缓冲液。结果表明缓冲液的ｐＨ影响ＣＺＥ对阿片受体的分析,当ｐＨ为９．０时分析效果最理想,重现性良好,测得的两个主峰与同批样品进行ＳＤＳ－ＰＡＧＥ分析得到的两个条带相符。用ＣＺＥ分析抗独特型抗羟甲芬太尼抗体（ＩｇＧ）,表明用ＰｒＯｔｅｉｎＡ－Ｓｅｐｈａｒｏｓｅ亲和色谱分离得到部分纯化的ＩｇＧ,迁移时间不同于对照豚鼠的ＩｇＧ。     

双■唑啉化合物偶联聚酯的研究Ⅱ.聚对苯二甲酸乙二酯的偶联反应

用特性粘度（［η］）和羧值为参数，研究了双唑啉化合物（ＢＯＺ）对聚对苯二甲酸乙二酯（ＰＥＴ）的扩链反应动力学过程，表明ＢＯＺ是与ＰＥＴ中羧基反应，考察了不同工艺生产的ＰＥＴ的扩链效果，结果说明达到的［η］极大值取决于原始ＰＥＴ的［η］与羧值之比     

The effect of the components of the PdCl2/Fe/I2/Py catalytic system on nitrobenzene carbonylation to ethyl N-phenylcarbamate

The PdCl₂/Fe/I₂/Py catalytic system (Py-pyridine), reported to be highly active in the reaction of nitrobenzene carbonylation to ethyl phenylcarbamate was studied. The present paper describes the role of catalyst components and its effect on the activity and selectivity of the catalyst. The increase in the amount of PdCl₂ in the system while retaining a constant level of the other catalyst components, results in the increase of both carbamate and aniline yields. The increase in the amount of iron while retaining the other components constant, initially causes an increase in the carbamate yield; however, at Fe: Pd ratios higher than 36, the carbamate yield remains constant. The change in the amount of iron has no effect on the amount of aniline formed in the system. An increase in the amount of iodine in the system while retaining the other components constant, results in a decrease in carbamate yield and a considerable increase in the aniline yield of the reaction products.     

Alteration in photosystem II photochemistry of thylakoids isolated from senescing leaves of wheat seedlings

Wheat seedlings, grown for 7 days in the light, were allowed to senesce in the light or dark, and the change in the photosystem II (PS II) photochemistry of chloroplasts isolated from the primary leaves of these seedlings was investigated. The decrease in oxygen evolution and the fast fluorescence results indicated that the impairment of PS II in the leaves of seedlings senescing in the light was different from that in the leaves of seedlings senescing in the dark. Thermoluminescence studies showed a structural modification in the Q_B protein of chloroplasts isolated from leaves senescing in the light and an alteration in the S state transition of chloroplasts isolated from leaves senescing in the dark.     

壳聚糖及其在分析化学中的应用

综述了壳聚糖、甲壳素在污水处理、电化学、原子吸收光谱、高效液相色谱、吸光光度法中的应用。引用文献28篇。     

Sol-gel Transition of Methylcellulose Solution in the Coexistence of Hexadecyltrimethylammonium Bromide and Sodium Chloride

The sol-gel transition of methylcellulose (MC) solution in the presence of NaCl and hexade-cyltrimethylammonium bromide (HTAB), together with MC/NaCl solution in the presence of HTAB and MC/HATB solution in the presence of NaCl, was investigated by the rheolog-ical measurements. It has been found that the sol-gel transition temperature of MC solution decreases linearly with the concentration of NaCl in solution but increases linearly with the concentration of HTAB in solution, respectively. However, the sol-gel transition temperature of MC/NaCl solution in the presence of HTAB keeps the same value, independent of theconcentration of HTAB in solution. On the other hand, the sol-gel transition temperature of MC/HTAB solution decreases linearly with the concentration of NaCl in solution. The experimental results suggest that, for MC/NaCl solution in the presence of HTAB, the salt-induced spherical micelles of HTAB should have formed in bulk solution. For MC solution in the absence of NaCl, no spherical micelles have been formed in bulk solution, though the concentration of HTAB in our experiment is almost one order of magnitude higher than the critical micelle concentration of HTAB in polymer-free solution. In fact, due to adsorption of HTAB on MC chains, the realconcentration of HTAB in bulk solution, is much less than the apparent concentration of HTAB dissolved in MC solution.     

Radial structure and property relationship in the thermal stabilization of PAN precursor fibres

Here we report on the role of oxygen in the evolution of radial heterogeneity in the fibre structure and properties of PAN fibres stabilized in air and vacuum at different temperatures. Modulus mapping by Nano-indentation showed heterogeneous modulus distribution in the fibres treated in air, while no variation in modulus was observed in fibres processed in vacuum. Raman spectroscopy and elemental analysis revealed that the temperature dependent oxygen diffusion from skin to core of the fibres assisted in the evolution of higher extent of sp²-hybridized carbons in the skin compared to core of the air treated samples. Conversely, no radial structure variations were observed in the vacuum treated fibres. Higher modulus in the skin of air-treated fibres was due to the formation of compact structures which was associated with the enhanced intermolecular interactions facilitated by the formation of C=C bonds within the polymer backbone, promoted by oxidative-dehydrogenation reaction. Supporting these observations, the fracture morphology examined by SEM showed a brittle fracture in the skin and ductile fracture in the core.     

Analytical strategies to determine antibiotic residues in fish

The accelerated growth of aquaculture has resulted in a series of harmful effects to human health. The widespread and unrestricted use of antibiotics in this industry, to prevent bacterial infections, leads to remaining amounts in the aquatic environment. This has resulted in the emergence of antibiotic-resistant bacteria in aquaculture environments, in the increase in antibiotic resistance in fish pathogens as well as in the transfer of these resistance determinants to human pathogens. Moreover, the use of large amounts of antibiotics may lead to the presence of residual antibiotics in fish tissue and fish products. Fluoroquinolones, tetracyclines, penicillins, sulphonamides and other antibiotics, exhibiting activity against both Gram-positive and Gram-negative bacteria, are widely used for the treatment and prevention of diseases in fish. An extended and comprehensive review on the recent analytical methodologies concerning antibiotic residues in fish reported in the literature is provided in the present article. Emphasis is given on sample preparation regarding isolation and purification, chromatographic conditions and method validation according to legislation. Results of published assays are comparatively presented and criticised.     

ESR方法检测竹红菌素的半醌负离子自由基

从顺磁共振波谱检测到通过竹红菌素的光诱导还原和基态竹红菌素跟脂肪胺的电子转移两条途径所得到的自由基信号, 并由电化学还原得到同一自由基, 确认它为半醌负离子自由基。竹红菌素溶液中加入芳香胺观察不到ESR信号。它的3,10位上与醌基相邻近的羟基离解以后, 无论在基态还是在激发态都观察不到ESR信号。此外, 还从吸收光谱观察到半醌负离子自由基吸收以及竹红菌素跟脂肪胺之间的相互作用。     

Photoelectric effects on chlorophyll fluorescence of photosystem II in vivo. Kinetics in the absence and presence of valinomycin

Fluorescence induction curves (F(t)) in low intensity 1s light pulses have been measured in leaf discs in the presence and absence of valinomycin (VMC). Addition of VMC causes: (i) no effect on the initial fluorescence level Fo and the initial (O-J) phase of F(t) in the 0.01-1 ms time range. (ii) An approximately 10% decrease in the maximal fluorescence Fm in the light reached at the P level in the O-J-I-P induction curve. (iii) Nearly twofold increase in the rate and extent of the F(t) rise in the J-I phase in the 1-50 ms time range. (iv) A 60-70% decrease in the rise (I-P phase) in the 50-1000 ms time range with no appreciable effect, if at all, on the rate. System analysis of F(t) in terms of rate constants of electron transfer at donor and acceptor sides have been done using the Three State Trapping Model (TSTM). This reveals that VMC causes: (i) no, or very little effect on rate constants of e-transfer reactions powered by PSII. (ii) A manifold lower rate constant of radical pair recombination (k(-1)) in the light as compared to that in the control. The low rate constant of radical pair recombination in the reaction center (RC) in the presence of VMC is reflected by a substantial increase in the nonzero trapping efficiency in RCs in which the primary quinone acceptor (Q(A)) is reduced (semi-open centers). This causes an increase in their rate of closure and in the overall trapping efficiency. Data suggest evidence that membrane chaotropic agents like VMC abolish the stimulation of the rate constant of radical pair recombination by light. This light stimulation that becomes apparent as an increase in Fo has been documented before [Biophys. J. 79 (2000) 26]. It has been ascribed to effects of (changes in) local electric fields in the vicinity of the RC. The decrease of the I-P phase is attributed to a decrease in the photoelectric trans-thylakoid potential in the presence of VMC. Such effects have been hypothesized and illustrated.     

Effect of plasticizer concentration on the hysteresis,tear strength and stress-relaxation characteristics of black-loaded rubber vulcanizate

The effect of plasticizer concentration on the stress softening, tear strength and stress relaxation of black loaded bromobutyl rubber vulcanizate has been investigated. The stress softening in the rubber vulcanizate, an energy dissipative process at higher strain, may be explained primarily by changes that take place in the rubber phase of the filled vulcanizate. Increased plasticizer concentration leads to decrease in the equilibrium hysteresis. A quantitative relationship between energy density and hysteresis has been derived, which is applicable at and below the elongation at break. Increase in plasticizer concentration results in decrease in the effective diameter of the tip of the tear, which in turn decreases the tear strength. Rate of relaxation decreases with increase in the plasticizer concentration in the carbon-black-filled vulcanizate.     

Changes in density and surface tension of water in silica pores

 The density and surface tension of water in small pores of silicas have been investigated. These physical properties of water in the pores were calculated from a comparison of pore volumes and pore radii which were estimated from adsorption and desorption isotherms of nitrogen and water. Below a pore radius of about 5 nm both the density and the surface tension of water in the pores were smaller than those of the bulk liquid and decreased with a decrease in pore size. The density of water in the pores decreased with an increase in the concentration of surface hydroxyl groups. Similarly the surface tension of water in the pores is influenced by the surface hydroxyl groups. Anomalous changes in the density and surface tension of the water in the pores are attributed to the interaction of water molecules with surface hydroxyl groups and hydrogen-bond formation among water molecules. Received: 20 April 1999 Accepted in revised form: 17 November 1999