OBSERVATION OF A RATE ENHANCING ANION-IONIC STRENGTH INTERACTION IN THE POLAROGRAPHIC REDUCTION OF Ga(III) IN HALIDE-Sr(C104)2 MEDIA

Abstract

Preliminary polarographic experiments have revealed that in sufficiently concentrated alkaline earth perchlorates C1^?, Br^?, and I^? catalyze the reversible reduction of Ga(III) to the metal. The results are discussed relative to earlier work which indicated that reversibility is realizable only in the presence of SCN^? or N₃ ^?     

动态光散射研究盐对Gemini表面活性剂网状聚集体的影响

以动态光散射为主要手段研究了盐对羧酸盐Gemini表面活性剂O,O′-双(2-月桂酸钠)-p-二苯氧(记为C12φ2C12)自组织的影响.结果表明盐的加入很容易使C12φ2C12的网状聚集体转变为小(流体力学半径Rh,app约几纳米)和大(Rh,app100 nm)两种尺寸共存的聚集体,1,6-二苯基-1,3,5-己三烯(DPH)探针增溶实验证实小尺寸聚集体为核-壳结构的似球胶束,流变学测量说明大尺寸聚集体可能已经是线型的核-壳胶束.这种行为被归结为初始的网状聚集体不稳定,添加的反离子与C12φ2C12头基结合破坏了网状结构的亲水亲油平衡,促使了它们的转变.盐效应规律表现为MgCl2NaCl、Bu4NBrMe4NBrEt4NBrPr4NBr,这里Bu4NBr不遵循上述静电力顺序的原因是它提供了携带的丁基与C12φ2C12烷烃链疏水相互作用的附加力.     

表面活性剂对部分水解聚丙烯酰胺溶液抗盐性的影响

通过实验研究了阴离子表面活性剂(SDS)、非离子表面活性剂(OP-10)、两性表面活性剂(C12BE)浓度及KCl浓度对部分水解聚丙烯酰胺(阴离子型,HPAM)水溶液黏度的影响规律,进而分析各因素对聚合物溶液抗盐性的影响。实验结果表明:当表面活性剂浓度低于临界缔合浓度CAC时,聚合物溶液黏度变化不大;高于CAC后,随着表面活性剂浓度增大,聚合物溶液黏度急剧增加;当表面活性剂浓度达到聚合物饱和浓度PSP时,聚合物溶液黏度达到最大值;再加入阴离子和两性表面活性剂,将导致黏度降低,而加入非离子表面活性剂不再改变聚合物溶液的黏度,无机盐KCl对聚合物溶液有双重作用,低浓度KCl促进聚合物溶液黏度升高,高浓度KCl则导致聚合物溶液黏度急剧降低后趋于稳定,在相同KCl浓度下,三种表面活性剂的抗盐能力表现为:SDSOP-10C12BE。     

流动注射-分光光度法测定河口水中氨氮的盐效应及校正

建立了流动注射-分光光度法测定河口水中氨氮的盐效应的校正办法。样品溶液中的钙离子、镁离子是造成盐效应的主要因素。低盐区域(盐度0~10)随盐度增加,校正系数迅速降低;高盐区域(盐度10~30)随盐度增加,校正系数缓慢增加。氨氮的线性范围为3.00~300μg·L-1,方法的检出限(3S/N)为1.97μg·L-1。对20.0μg·L-1氨氮标准溶液连续测定7次,测定值的相对标准偏差为4.5%。用标准加入法做方法的回收试验,测得回收率在80.7%~108%之间。     

Microwire Chronoamperometric Determination of Concentration,Diffusivity, and Salinity for Simultaneous Oxygen and Proton Reduction

A microwire chronoamperometric method is reported employing a 25 µm diameter platinum microwire for multi‐parameter electroanalysis with digital simulation‐based evaluation (employing DigiElch 4.F). Concentration and diffusion coefficient data are obtained for the reduction of oxygen and for the reduction of protons individually and simultaneously in saline (0.1 M to 4.0 M NaCl) electrolyte media. The diffusion coefficient and concentration data for oxygen allows salinity levels to be estimated. The microwire chronoamperometry method offers versatility and precision due to (i) a slow approach to steady state (when compared to microdisc methods) and (ii) insignificant viscosity effects (when compared to hydrodynamic methods).     

Proteome profile of salt gland‐rich epidermis extracted from a salt‐tolerant tree species

Preparation of proteins from salt‐gland‐rich tissues of mangrove plant is necessary for a systematic study of proteins involved in the plant's unique desalination mechanism. Extraction of high‐quality proteins from the leaves of mangrove tree species, however, is difficult due to the presence of high levels of endogenous phenolic compounds. In our study, preparation of proteins from only a part of the leaf tissues (i.e. salt gland‐rich epidermal layers) was required, rendering extraction even more challenging. By comparing several extraction methods, we developed a reliable procedure for obtaining proteins from salt gland‐rich tissues of the mangrove species Avicennia officinalis. Protein extraction was markedly improved using a phenol‐based extraction method. Greater resolution 1D protein gel profiles could be obtained. More promising proteome profiles could be obtained through 1D‐LC‐MS/MS. The number of proteins detected was twice as much as compared to TUTS extraction method. Focusing on proteins that were solely present in each extraction method, phenol‐based extracts contained nearly ten times more proteins than those in the extracts without using phenol. The approach could thus be applied for downstream high‐throughput proteomic analyses involving LC‐MS/MS or equivalent. The proteomics data presented herein are available via ProteomeXchange with identifier PXD001691.     

Phosphonobetaine/sulfur dioxide copolymer by Butler’s cyclopolymerization process

The zwitterionic monomer, ethyl 3-(N,N-diallylammonio)propanephosphonate and sulfur dioxide were cyclocopolymerized in DMSO using azobisisobutyronitrile or ammonium persulfate as initiators to afford a pH-responsive polyphosphonobetaine/SO₂ (PPB/SO₂) copolymer. The polymers, on treatment with HCl and NaOH, gave the aqueous solutions of the corresponding cationic polyphosphononic acid (CPP) and anionic polyphosphonate (APP). The solution properties of the PPB having two pH-responsive functionalities were investigated in detail by potentiometric and viscometric techniques. Basicity constants of the amine and phosphonate groups in APP were found to be “apparent” and as such follow the modified Henderson–Hasselbalch equation. The incorporation of SO₂ moiety has resulted in the decrease of basicity constant of the nitrogens in the copolymer by staggering ?2 units of log K in compare to that of the corresponding homopolymer. The basicity difference is expected to have an effect on the chelating properties of the polymers. In contrast to many polycarbo- and -sulfobetaines, the PPB was all found to be soluble in salt-free water as well as in salt (including Ca²⁺ and Li⁺)-added solutions. The PPB demonstrated ‘antipolyelectrolyte’ viscosity behavior and found to have higher viscosity values in LiCl than in NaCl or NaI.     

盐/甲醇体系荧光光谱的分析和指认

研究了CaCl2、LiCl和Ca(NO3)2在甲醇溶液中的荧光光谱,并对溶液中可能的团簇构型采用密度泛函理论和含时(TD)密度泛函理论中的B3LYP方法进行结构优化和激发能计算.实验结果表明CaCl2和LiCl与甲醇形成了具有荧光性质的簇合物,且随着CaCl2和LiCl浓度的增加溶液的荧光强度整体呈增强趋势,而Ca(NO3)2与甲醇相互作用使甲醇发生荧光猝灭.理论计算得到盐/甲醇溶液中可能存在多种簇合物,但能使甲醇溶液荧光增强的团簇构型主要为[CaCl(CH3OH)n]+和LiCl(CH3OH)n,而NO3-与甲醇通过氢键作用形成簇合物的振荡强度几乎为零,解释了NO3-使甲醇发生荧光猝灭的现象.     

Monitoring the oleuropein content of olive leaves and fruits using ultrasound‐ and salt‐assisted liquid–liquid extraction optimized by response surface methodology and high‐performance liquid chromatography

A novel and rapid ultrasound‐ and salt‐assisted liquid–liquid extraction coupled with high‐performance liquid chromatography has been optimized by response surface methodology for the determination of oleuropein from olive leaves. Box–Behnken design was used for optimizing the main parameters including ultrasound time (A), pH (B), salt concentration (C), and volume of miscible organic solvent (D). In this technique, a mixture of plant sample and extraction solvent was subjected to ultrasound waves. After ultrasound‐assisted extraction, phase separation was performed by the addition of salt to the liquid phase. The optimal conditions for the highest extraction yield of oleuropein were ultrasound time, 30 min; volume of organic solvent, 2.5 mL; salt concentration, 25% w/v; and sample pH, 4. Experimental data were fitted with a quadratic model. Analysis of variance results show that BC interaction, A², B², C², and D² are significant model terms. Unlike the conventional extraction methods for plant extracts, no evaporation and reconstitution operations were needed in the proposed technique.     

Assessment of corrosion resistance of surface-coated galvanized steel by analysis of the AC impedance spectra measured on the salt-spray-tested specimen

In the present work, corrosion resistance of surface-coated galvanized steel was quantitatively determined by an analysis of the alternating current (AC) impedance spectra measured on the salt-spray-tested specimen. To evaluate the corrosion resistance of the surface-coated galvanized steel, AC impedance spectroscopy was performed on the salt-spray-tested specimen previously exposed to salt-sprayed corrosive environment. From the analysis of the impedance spectra, the area fraction transient of white rust θ ₂(t) was theoretically derived from the equivalent circuit equation by using two fitting parameters. The values of the two fitting parameters were determined by fitting the empirical transient equations to the area fraction of the resin coating layer and to the total resistance obtained from the impedance spectra measured, respectively. From the analyses of θ ₂(t) for four kinds of surface-coated galvanized steels with various resin coating layers, it is indicated that as the values of the two fitting parameters decrease in the order of CP, GI, OD and OM (commercial trade names) specimens, the corrosion resistance increases in that order as well. Furthermore, from the quantitative comparison of the two fitting parameters with the polarization resistance of the upper resin coating layer R _p determined from the potentiodynamic polarization curve, it is suggested that the two fitting parameters decrease in value as well with increasing R _p.