2,6-二乙氧基-β-环糊精对铕（Ⅲ）-强力霉素络合物包合作用的研究及其分析应用

在pH=9.4的NH4Cl-NH3·H2O的缓冲溶液条件下,强力霉素能与铕(Ⅲ)生成二元络合物并发射出铕(Ⅲ)位于612 nm处的特征荧光,加入2,6-二乙氧基-β-环糊精后,体系的荧光强度显著增强,且增强的荧光强度与强力霉素的浓度呈线性关系,据此建立了荧光分光光度法测量强力霉素的方法。在最佳实验条件下,测量的线性范围和检出限分别为6.2×10-8~1.3×10-5mol/L和1.4×10-8mol/L。本方法曾用于血样和尿样中强力霉素的测定。本研究讨论了荧光增强的机理。     

2,6-二乙氧基-β-环糊精对铕(Ⅲ)-强力霉素络合物包合作用的研究及其分析应用

在pH=9.4的NH4Cl-NH3*H2O 的缓冲溶液条件下,强力霉素能与铕(Ⅲ)生成二元络合物并发射出铕(Ⅲ)位于612 nm处的特征荧光,加入2,6-二乙氧基-β-环糊精后,体系的荧光强度显著增强,且增强的荧光强度与强力霉素的浓度呈线性关系,据此建立了荧光分光光度法测量强力霉素的方法.在最佳实验条件下,测量的线性范围和检出限分别为6.2×10-8～1.3×10-5 mol/L和1.4×10-8 mol/L.本方法曾用于血样和尿样中强力霉素的测定.本研究讨论了荧光增强的机理.     

以Eu（Ⅲ）作荧光探针时间分辨荧光法测定吡哌酸

建立了一种以Eu(Ⅲ)作为荧光探针,时间分辨荧光法测定吡哌酸的新方法。吡哌酸和Eu(Ⅲ)配合后在受到紫外光激发时发生分子内能量转移,配合物发射铕离子的特征荧光。以荧光强度进行条件优化,结果表明,在pH 8.2的缓冲溶液中,加入适量阴离子表面活性剂十二烷基硫酸钠(SDS)后,体系荧光强度大大增强。方法的检出限(3σ)为2×10-8mol/L,测定精度RSD为0.62%(2×10-6mol/L,n=11)。吡哌酸溶液在5×10-8~5×10-6mol/L范围内线性关系良好。该方法可用于吡哌酸片剂及尿液中痕量吡哌酸的测定,药片测定结果与药典方法基本一致。     

姜黄素-La3+-CTMAB-核酸体系的荧光增强效应及其应用

研究了镧离子(La3+)-姜黄素(CU)-十六烷基三甲基溴化铵(CTMAB)-核酸荧光增强体系.建立了测定核酸的新方法.体系的最优条件为:六次甲基四胺(HMTA)-HCl缓冲溶液(pH 5.80)中,1.00× 10-3 mol/L阳离子表面活性剂CTMAB存在下,姜黄素浓度为2.00×10-5 mol/L,La3+的浓度为1.40×10-4 mol/L时,核酸能增强La3+ -CU络合物的荧光强度,而且体系荧光的增强程度与核酸的加入量在一定范围内呈线性关系.fsDNA,ctDNA和yRNA线性范围分别为7.00×10-4～10.00 mg/L,4.00×10-4～10.00 mg/L和7.00×10-4～10.00 mg/L;检出限分别为0.17,0.02和0.14 μg/L.与已报道的核酸的分析方法相比,本方法具有较宽的线性范围和较高的灵敏度.研究表明,核酸对体系荧光的增强源于DNA主链上PO3-4与CU之间的静电结合,以及通过氢键和疏水力进行的沟槽式结合,为探针分子提供了疏水性的微环境,降低了体系的非辐射能量损失,使体系的荧光强度增加.     

诺氟沙星荧光光度法测定微量Al(Ⅲ)

铝对荧光试剂诺氟沙星有强的荧光增强作用,据此建立了测定微量铝的荧光分析方法。选择最大激发与发射波长分别为278 nm和441 nm,在pH 4.10的HAc-NaAc介质中,诺氟沙星的荧光强度变化与Al(Ⅲ)浓度呈良好的线性关系,线性范围为7.00×10-6~1.00×10-3mol/L,检出限为2.00×10-8mol/L,常见的共存离子不干扰测定。本方法已用于实际样品中Al(Ⅲ)的测定。     

镧(Ⅲ)对铽(Ⅲ)-邻-氟苯甲酸-乙二胺体系荧光的增强及其分析应用

在pH 10.0的水溶液中,5.0×10-4 mol/L的La(Ⅲ)可使Tb(Ⅲ)-o-FBA(邻-氟苯甲酸)-EDA(乙二胺) 体系的荧光增强78倍.以1.0×10-9 mol/L的Tb(Ⅲ)试验,体系的最大荧光条件如下:o-FBA浓度为6.0×10-3 mol/L,EDA体积分数为1%,激发光波长为339 nm,测量的荧光发射波长为546 nm.实验表明,在上述条件下,Tb(Ⅲ)的浓度在5.0×10-10～2.0×10-7 mol/L范围与体系的荧光强度呈线性关系,据此建立了测定痕量铽的荧光光度分析法,测定的相对标准偏差为0.50%,Tb(Ⅲ)的检出限为5.0×10-11 mol/L.     

钇(Ⅲ)对铽(Ⅲ)-对苯二甲酸-乙二胺体系的荧光增强及其分析应用

在pH8.0的水溶液中 ,8.0×10-4mol/L的Y(Ⅲ)可使Tb(Ⅲ) -对苯二甲酸 -乙二胺体系的荧光增强84倍;以1.0×10-8 mol/L的Tb(Ⅲ)试验 ,体系的最大荧光条件为对苯二甲酸浓度1.0×10-3 mol/L,乙二胺水溶液体积分数1 %,用量0.5mL ,激发光波长296nm ,测量的荧光发射波长546nm;实验表明 ,Tb(Ⅲ)的浓度在2.0×10-9 ～2.0×10-7mol/L范围与体系的荧光强度呈线性关系 ,据此建立了测定痕量Tb(Ⅲ)的荧光光度分析法 ,测定结果的相对标准偏差为0.80 % ,Tb(Ⅲ)的检出限为5.0×10 -11mol/L。     

血红蛋白催化荧光法测定其氢供体底物酪氨酸

利用血红蛋白(Hb)的过氧化物酶特性,催化H2O2氧化氢供体底物酪氨酸(Tyr)的荧光反应,实验发现NH3配体对该反应产物的荧光强度有增强作用。通过反应机理的探讨,获得了反应速率方程。在NH3 NH4Cl的缓冲体系中优化了反应条件,建立了新的测定酪氨酸的催化荧光分析法。酪氨酸浓度在2.0×10-7～2.0×10-5mol/L范围内呈现良好的线性关系(r=0.9995),方法的检出限为4.63×10-9mol/L。已用于实际样品的测定。     

基于银纳米粒子的荧光增强法测定依诺沙星

以NaBH4为还原剂,聚乙烯吡咯烷酮为稳定剂,室温下制备了银纳米粒子(AgNPs),用荧光、紫外光谱等进行表征。依诺沙星与聚乙烯吡咯烷酮纳米银相互作用后,使AgNPs荧光增强,由此建立测定依诺沙星的新方法。在最佳实验条件下,体系的荧光强度之比(F/F_0)与依诺沙星浓度呈良好线性关系,线性范围为1.0×10~(-7)~1.0×10~(-5) mol/L,检出限为8.0×10~(-8) mol/L。该方法用于实际样品中依诺沙星含量的测定,回收率为94.5%~99.8%。     

荧光猝灭法测定磷酰化氨基酸

建立了通过磷酰化氨基酸水解产生无机磷酸盐猝灭铽离子-钛铁试剂络合物(Tb3 -TR)荧光探针的间接荧光法测定三种磷酰化氨基酸。在最佳实验条件下,方法测定磷酰化丝氨酸(P-Ser)、磷酰化苏氨酸(P-Thr)和磷酰化酪氨酸(P-Tyr)的线性范围分别为5.0×10-8~5.0×10-7mol/L、5.0×10-8~6.0×10-7mol/L、5.0×10-8~6.0×10-7mol/L;检出限分别为2.06×10-8mol/L、1.13×10-8mol/L和1.74×10-9mol/L。该方法最后用于卵黄高磷蛋白中含磷量的测定,取得定量结果。     

Phase diagrams and structures of lecithin/water systems with branched lecithin components

The influence of chain branching on the phase transition parameters and structures of the homologous series of 1-(x-methylpalmitoyl)-2-hexadecyllecithins in the water-saturated two-phase region (50 wt.% water) were studied by differentialscanning-calorimetry as a function of the position x of methyl branching. With increasing x a linear decrease in the enthalpies and alternating temperatures of main transition were observed. The phase diagram of the ternary system 1-(3-methyl-palmitoyl)-2-hexadecyllecithin/1,2-dipalmitoyllecithin/water (50 wt.% water) showed that both components are completely miscible within the high-temperature phase (L -phase). However, in the low-temperature phase (gel phase), the components are partially miscible only. It follows that gel phases with interdigitated chains and those with tilted chains are not completely miscible. The phase diagram of the ternary system 1,2-di-(8-methylpalmitoyl)-lecithin/1,2-dipalmitoyllecithin/water (50 wt.% water) showed that both components are completely miscible within the high-temperature phase and low-temperature phase. Within the concentration range between the mole fraction x=0.91 and x=0.97, a drop-like course in the phase diagram was obtained.     

Phase behavior of the lecithin/water/isooctane and lecithin/water/decane systems

The isothermal pseudo-ternary-phase diagram was determined at 25 degrees C for systems composed oflecithin, water, and, as oil, either isooctane or decane. This was accomplished by a combination of polarizing microscopy, small-angle X-ray scattering, and NMR techniques. The lecithin-rich region of the phase diagram is dominated by a lamellar liquid-crystalline phase (Lalpha). For lecithin contents less than 60% and low hydration (mole ratio water/lecithin = W0 < 5.5), the system forms a viscous gel of branched cylindrical reverse micelles. With increase in the water content, the system phase separates into two phases, which is either gel in equilibrium with essentially pure isooctane (for lecithin < 25%) or a gel in equilibrium with Lalpha (for lecithin > 25%). These two-phase regions are very thin with respect to water dilution. For 8 < W0 < 54 very stable water-in-oil emulsions form. It is only after ripening for more than 1 year that the large region occupied by the emulsion reveals a complex pattern of stable phases. Moving along water dilution lines, one finds (i) the coexistence of gel, isooctane and Lalpha, (ii) equilibrium between reverse micelles and spherulites, and, finally, (iii) disconnected reverse micelles that fail to solubilize water for W0 > 54. This results in a Winsor II phase equilibrium at low lecithin content, while for lecithin > 20% the neat water is in equilibrium with a reverse hexagonal phase and an isotropic liquid-crystalline phase. The use of the decane as oil does not change the main features of the phase behavior.     

Interactions of hemoglobin with lecithin liposomes

In this paper, the interaction of hemoglobin (Hb) with lecithin liposomes is studied by UV-vis spectroscopy, fluorescent spectroscopy, and transmission electron microscopy. The adsorption of Hb on liposomes is likely to be related to the hydrophobic interaction between Hb and liposomes, which brings about the increase of the microenvironmental polarity (I ₁/I ₃) and the decrease of the fluorescence polarization (P) of lecithin liposomes. These results are considered to be that the adsorption of Hb on liposomes makes the spaces between the lecithin molecules increase, and a temporary gap is consequently formed in the liposomal bilayer membranes. The leakage of aqueous-space marker from the liposomes is increased with the addition of Hb.     

Homogeneous lecithin from cottonseed meal

The possibility of using industrial cottonseed meal for the production of homogeneous lecithin has been shown.Institute of the Chemistry of Plant Sciences, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 295–296, May–June, 1984.     

Biocompatible lecithin organogels: structure and phase equilibria

The microstructure of organogels formed upon the addition of tiny amounts of water to a solution of lecithin in fatty acid esters (viz. isopropylpalmitate and ethyloleate) was investigated by means of molecular self-diffusion measurements. In both systems lecithin and water form disconnected cylindrical reverse micelles. The ternary phase map for the lecithin/water/isopropylpalmitate has been investigated in detail. The organogel exists in a narrow region close to the lecithin-oil binary axis; for higher water content equilibrium between lamellae and reverse micelles is found. Lamellar phase occupies the lecithin-rich region, close to the lecithin corner (with the exception of a small island of hexagonal phase) and coexists with neat water close to the water-lecithin axis. The remaining part of the phase map shows the three-phase coexistence of water, oil, and lamellar phase.