A microfluidic device using a green organic light emitting diode as an integrated excitation source

A simply fabricated microfluidic device using a green organic light emitting diode (OLED) and thin film interference filter as integrated excitation source is presented and applied to fluorescence detection of proteins. A layer-by-layer compact system consisting of glass/PDMS microchip, pinhole, excitation filter and OLED is designed and equipped with a coaxial optical fiber and for fluorescence detection a 300 microm thick excitation filter is employed for eliminating nearly 80% of the unwanted light emitted by OLEDs which has overlaped with the fluorescence spectrum of the dyes. The distance between OLED illuminant and microchannels is limited to approximately 1 mm for sensitive detection. The achieved fluorescence signal of 300 microM Rhodamine 6G is about 13 times as high as that without the excitation filter and 3.5 times the result of a perpendicular detection structure. This system has been used for fluorescence detection of Rhodamine 6G, Alexa 532 and BSA conjugates in 4% linear polyacrymide (LPA) buffer (in 1 x TBE, pH 8.3) and 1.4 fmol and 35 fmol mass detection limits at 0.7 nl injection volume for Alexa and Rhodamine dye have been obtained, respectively.     

Chiral Cu(II) complex catalyzed enantioselective addition of phenylacetylene to N-aryl arylimines

Chiral tridentate N-tosylated aminoimine ligands were used in the Cu(II)-catalyzed enantioselective addition of phenylacetylene to N-aryl arylimines, affording products up to 92% ee.     

衬钽管石墨炉中小量氢气的影响及稀土基质激光晶体中铕的测定

通过纯氩中加入小量氢气,研究了保护气体对衬鉏管石墨炉分析性能的影响,结果表明,采用5％H_2-Ar作保护气体,可以显著提离衬鉏管的成品率,明显延长衬鉏管的使用寿命,使衬钽管的测定重现性得到改善,而对测定灵敏度没有明显影响。干扰试验表明,本方法可直接用于稀土基质激光晶体中铕的测定,分析结果与计算值基本一致。     

AC calorimetric study of phase transitions in phosphatidylcholine-cholesterol systems

Using an ac calorimetric method, detailed behaviour of the heat capacity in dipalmitoyl-phosphatidylcholine-cholesterol system was studied in the cholesterol concentration less than 5 mol%. It was revealed that the heat capacity near the main transition was composed of at least four anomalies, i.e., multipeak took place in the heat capacity. This fact indicates that a simple theory explaining coexistence of two phases in two component systems does not work in the multipeak region. Then, relation between the multipeak heat capacity and the change of the ripple structure with the cholesterol concentration should be taken into account, when we consider thermodynamical behaviour of the systems.

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Zusammenfassung Mittels AC-Kalorimetrie wurde bei Cholesterol-Konzentrationen von weniger als 5 mol% das Verhalten der Wärmekapazität im System Dipalmitoylphosphatidylcholin-Cholesterol untersucht. Es wurde gezeigt, daß sich die Wärmekapazität in der Nähe der Hauptumwandlung aus mindestens vier Anomalien zusammensetzt, d.h. bei der Wärmekapazität kann ein Multipeak beobachtet werden. Diese Tatsache zeigt, daß eine einfache Theorie, welche die Koexistenz zweier Phasen in einem Zweikomponenten-System erklärt, für die Multipeakregion nicht geeignet ist. Weiterhin sollte bei Überlegungen zum thermodynamischen Verhalten von Systemen eine Beziehung zwischen der Multipeak-Wärmekapazität bzw. der Welligkeitsstruktur und der Cholesterol-Konzentration berücksichtigt werden.

     

Determination of acetone, hexanal and heptanal in blood samples by derivatization with pentafluorobenzyl hydroxylamine followed by headspace single-drop microextraction and gas chromatography–mass spectrometry

In the study, we developed a simple, rapid, sensitive, and inexpensive method for determination of the disease biomarkers of acetone, hexanal and heptanal in human blood. For the first time, derivatization of carbonyls with O-2,3,4,5,6-(pentafluorobenzyl)hydroxylamine (PFBHA) was combined with headspace single-drop microextractin (HS-SDME) and gas chromatography-mass spectrometry (GC–MS) and applied to the analysis of acetone, hexanal, and heptanal in human blood. At first, acetone, hexanal and heptanal in blood were derivatized with PFBHA and formed oximes in several seconds. Sequentially, the oximes were headspace extracted and concentrated by a microdrop solvent. Finally, the extracted oximes were analyzed by GC–MS. HS-SDME conditions and method validations were studied. Due to needing of only 2 μl organic solvent, short extraction time of 8 min, and simple operation, derivatization-HS-SDME was shown to be a rapid, simple, and inexpensive technique for analysis of acetone, hexanal, and heptanal in human blood. Moreover, it had low detection limit values from 0.24 to 0.62 nM, and good reproducibility (R.S.D. less than 12%).     

甲醇、乙醇、异丁醇对含水卵磷脂液晶结构影响的SAXS研究

本文报导采用小角X射线散射方法(SAXS)对甲醇、乙醇和异丁醇分别与含水卵磷脂所形成的液晶相结构的研究. 它们与水-卵磷脂形成的液品结构有较大区别. 在水-卵磷脂体系中, 随着含水量增加, 双分子层层间距增大. 但当醇类加入水-卵磷脂体系中, 随着醇类含量增加, 层间距变小, 随着醇类中碳链的增长, 支链的引入, 层间距变小趋势强化。     

三(2-苯并咪唑亚甲基)胺硝酸镍(Ⅱ)配合物的合成及结构

三（２－苯并咪唑亚甲基）胺简称ＮＴＢ与Ｎｉ（Ⅱ）的硝酸盐形成配合物Ｃ２８Ｈ３５Ｎ９Ｏ９Ｓ２Ｎｉ。本文报道其合成，红外光谱及晶体结构。该化合物为三斜晶系，空间Ｐ１↑－，ａ＝９．６５０（３），ｂ＝１２．７１６（２），ｃ＝１４．４３６Ａ，α＝１１．４６（２），β＝９１．６６（３），γ＝９７．５５（２）°，Ｖ＝１７１８（２）Ａ＾３，Ｚ＝２，Ｆ（０００）＝７９３，Ｄｃ＝１．４８ｇ／ｃｍ＾３，Ｍｒ＝７６４．１     

Fe（Ⅲ）－TEA－5－Br－PADAP－H_2O_2体系中催化波的研究及其应

在０．２ｍｏｌ·Ｌ￣（－１）ＮＨ＿４Ｃｌ－ＮＨ＿３·Ｈ＿２Ｏ底液中，（ｐＨ为９．２６），得到一个极为灵敏的Ｆｅ（Ⅲ）－ＴＥＡ－５－Ｂｒ－ＰＡＤＡＰ－Ｈ＿２Ｏ＿２配合吸附催化波，其峰电位为－０．７１Ｖ（ｖｓ．ＳＣＥ）。铁浓度在１．８×１０￣（－１０）～５．４×１０￣（－６）ｍｏｌ·Ｌ￣（－１）范围内与二阶导数波高呈线性关系。对该极谱波的性质进行了研究，证明是一种配合吸附催化波，并成功地应用于各类水样，钒催化剂中微量或痕量铁的测定。     

Simultaneous EQCM and diffuse reflectance UV-visible spectroelectrochemical measurements: poly(aniline-co-o-anthranilic acid) growth and property characterization

Piezoelectric diffuse reflectance spectroelectrochemistry (PDRSEC), a new technique of diffuse reflectance spectroelectrochemistry (DRSEC) in combination with electrochemical quartz crystal microbalance (EQCM), was developed to study the electrochemical copolymerization of aniline and o-anthranilic acid in 1.0 mol l(-1) HClO4 and the properties of these copolymers. The DRSEC using an integral sphere was proven to possess a higher optical sensitivity at the unpolished piezoelectric quartz crystal electrodes used than the mirror reflectance spectroelectrochemistry mode. The copolymers grown from the copolymerization bath of different molar fractions of o-anthranilic acid (F1, relative to the total amount of the two monomers) showed intermediate properties between those of the homopolymers, which varied gradually with F1. The swelling/dissolution behavior of the copolymers vs solution pH was traced via the EQCM frequency and resistance signals, and its large dependence on F1 was found and discussed. In a HAc-NaAc buffer solution at pH 5.6, the amount of adsorbed lysozyme was found to be positively correlated with F1, via an EQCM impedance investigation, demonstrating the feasibility of using poly(aniline-co-o-anthranilic acid) as a load-adjustable immobilization matrix for cationic proteins. The novel PDRSEC method proposed is highly recommended for surface electrochemistry studies at relatively rough electrodes.     

反气相色谱法研究聚丙烯结晶动力学及对熔点和结晶度的测定

<正> 研究聚合物的结晶动力学,过去大多采用膨胀计法和解偏振光法。曾有文献报道采用反气相色谱法测得聚乙烯等温结晶线。通过实验可知,测定聚丙烯结晶度时,试样热历史和测定前陈化温度的选择均影响测定结果。此外在测定聚丙烯试样的熔点时,保留图中出现了两个转折,经反复实验证实:此两转折对应于聚丙烯中不同晶形(α-、β-形)的熔点。