A new method of immobilizing ionic liquids into layered zirconium phosphates

In this work, a new method of a series of ion liquids (ILs) 1-alkyl-3-methylimidazolium chloride [Cnmim]Cl (n = 2, 4, 6, 8) intercalation into layered zirconium phosphates was investigated. It was found that theα-ZrP-2BA (i.e. pre-intercalated BA was arranged in a bilayer mode in the galleries ofα-ZrP) was a suitable host for intercalation ILs: ILs was inserted through exchanging pre-intercalated BA. And the intercalation orientation was investigated by use of X-ray diffraction (XRD) experiments and molecular modeling calculation.     

Synthesis of K-Zr phosphates by the molten salt method

Phosphates of K and Zr of a layered, microporous structure have been obtained by the molten salt method in a potassium nitrate medium in the temperatures range 573–823 K. Dependences of the product composition on the P/Zr atomic ratio and the temperature of synthesis were studied. The substances obtained have been characterized by XRD,¹H and³¹P NMR, and IR spectroscopy, and scanning electron microscopy.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2847–2851, December, 1996.     

Ammonium metal phosphates: Emerging materials for energy storage

The search for new materials that can hold the heteroatoms viz., nitrogen, oxygen and phosphorus becomes crucial for robust energy storage and conversion devices. Recently, ammonium metal phosphates (NH₄MPO₄, M = Mn²⁺, Ni²⁺, Co²⁺, Fe²⁺, etc.) and their hydrates have emerged as promising materials because of their attractive virtues; rapid electron transport because of the existence of more electroactive sites; and highly redox-active centres and rapid ion transport because of the intercalated water interactions. The synthesis of different dimensionalities (0D–3D) of these materials is facile and robust that boosts the electrochemical performances to some extent. This review emphasises the recent state-of-the-art work published on the ammonium metal phosphates for energy storage and a brief discussion on key challenges and future directions.     

Analysis and purification of peptide nucleic acids by denaturing PAGE

A flexible and convenient protocol for the analysis and purification of peptide nucleic acid (PNA) oligomers and PNA-peptide chimeras by denaturing PAGE is described. Vertical slab gel electrophoresis, 26% in polyacrylamide and 8 M urea at pH 3, was suitable for analysis of oligomers ranging in size from tetramers (4-mers) to tetradodecamers (24-mers). Single-base resolution of oligomers was achieved and separations are generally superior to those given by standard RP-HPLC techniques. The separation of a related series of PNA oligomers showed the distance migrated was linearly dependent on the logarithm of the molecular weight. The migration of oligomers through the gel is dependent on the number of basic functional groups present, such as amino groups, and the A and C content of the oligomer. PNAs are amenable to detection by UV-shadowing technique illuminated at 260 nm or Coomassie blue staining, both with similar, sub-microgram per band detection limits.     

大比表面负载氧化铁的氧化硅层柱磷酸锆制备和 催化性能研究

提出了一种以氧化硅层柱磷酸锆(SiO~2-ZrP)的前驱体,氨丙基硅酸酯嵌入磷酸锆(APS-ZrP)为载体制备负载氧化铁的氧化硅层术磷酸锆的新方法。与传统方法相比,新方法制得的样品具有较大的比表面和孔容。X射线粉末衍射(XRD)和程序升温还原(TPR)的结果表明采用新方法有利于氧化铁在载体表面的高度分散,分散阈值为0.25gFe~2O~3/g(SiO~2-ZrP),远超过直接以SiO~2-ZrP为载体浸渍草酸铁铵的传统方法得到样品。同时,用新方法制得的氧化铁催化剂表现了较高的乙苯脱氢活性,是一类值得研究的催化材料。     

Alternative visualization of SDS‐PAGE separated phosphoproteins by alizarin red S‐aluminum (III)‐appended complex

A novel fluorescence detection system using a chemosensor for phosphoprotein in gel electrophoretic analysis has been developed. The system employed the alizarin red S‐aluminum (III)‐appended complex as a fluorescent staining dye to perform the convenient and selective detection of phosphorylated proteins and total proteins in SDS‐PAGE, respectively. Therefore, a full and selective map of proteins can be achieved in the same process without resorting to other compatible detection methods. As low as 62.5 ng of α‐ (seven or eight phosphates) and β‐casein (five phosphates), 125 ng of ovalbumin (two phosphates), and κ‐casein (one phosphate) can be detected in approximately 135 min, with the linear responses of rigorous quantitation of changes over a 125–4000 ng range. As a result, alizarin red S‐aluminum (III) stain may provide a new choice for selective, economic, and convenient visualization of phosphoproteins.     

Detection of recombinant growth hormone in human plasma by a 2‐D PAGE method

Human growth hormone (GH) has several central metabolic functions including bone growth in childhood, and its anabolic and lipolytic effects in particular are assumed reasons for the abuse of GH by athletes. Human endogenous GH consists of a main 22 kDa variant and several isoforms. In contrast, recombinant GH consists of only one variant being identical to the main endogenous isoform. The method presented here separates different isoforms by 2‐D PAGE after isolation of GH from plasma using an immunoaffinity purification system. While samples containing endogenous GH yield up to four isoforms, samples with recombinant GH contain the main 22 kDa spot only. Normalized spot volumes (NSV) are calculated after addition of an internal standard and a discrimination limit was determined at 0.52 for the NSV of the main 22 kDa spot. Above this value, samples containing endogenous GH show at least the main 22 kDa isoform and the 20 kDa splice variant. In contrast, samples with a NSV >0.52 and only one spot are suspicious to contain recombinant GH. This method detects discrete isoforms of GH from plasma and discriminates endogenous GH from its recombinant analog, which makes it useful for doping control purposes.     

A technique for detecting antifungal activity of proteins separated by polyacrylamide gel electrophoresis

A technique was developed for the detection of antifungal activity of proteins after discontinuous polyacrylamide gel electrophoresis under native conditions. The antifungal activity is detected as growth inhibition zones in a homogeneous fungal lawn, grown in an agar layer spread on top of the polyacrylamide gel. The position of proteins with antifungal activity can be determined on a diffusion blot prepared from the same gel. The technique is illustrated for three antifungal plant proteins, i.e. alpha-purothionin, Urtica dioica agglutinin, and tobacco chitinase.     

Improved determination of tributyl phosphate degradation products (mono- and dibutyl phosphates) by ion chromatography

Tributyl phosphate (TBP) is a very important compound in the nuclear industry, particularly in the area of nuclear fuel reprocessing. This compound is used in the PUREX (plutonium and uranium refining extraction) process which consists of the extraction of uranium and plutonium from an aqueous nitric acid phase, for the purpose of recycling. But TBP may be degraded to dibutyl phosphate (DBP) and monobutyl phosphate (MBP) by dealkylation of one or two butoxy groups, respectively. We have compared and evaluated the capacity of two resins manufactured by Dionex (AS11 and AS5A) in the separation and measurement of these two degradation products. AS11 generates two interferences: nitrite/DBP and carbonate/MBP. The first one is the most serious. So, we have developed a method for oxidising nitrite ions to nitrate ions which have no trouble over the measurement. The second resin tested, AS5A, allows a very efficient separation between DBP and NO₂⁻ ions and a good separation between MBP and CO₃²⁻ in comparison with the AS11. The detection limits for the AS5A column are 0.13 μM for MBP and 0.71 μM for DBP (injection LOOP=50 μl).     

Validated hemoglobin-depletion approach for red blood cell lysate proteome analysis by means of 2D PAGE and Orbitrap MS

The analysis of the cytosolic red blood cell (RBC) proteome is negatively affected by the high intracellular amount of hemoglobin complicating the detection of low-abundant cytosolic proteins. In this study, an alternative approach for the preparation of hemoglobin-depleted RBC lysates is presented, which was established in combination with downstream 2D PAGE analysis and Orbitrap MS. Hemoglobin removal was accomplished by using HemoVoid(TM) depletion reagent, which enabled a very efficient enrichment of low-abundant proteins by simultaneously reducing the hemoglobin concentration of the sample. After defining selected sample preparation protocol characteristics including specificity/selectivity, precision and linearity, a 2D reference map (pH 4-7) of the cytosolic RBC proteome was generated and a total of 189 different proteins were identified. Thus, the presented approach proved to be highly suitable to prepare reproducible high-resolution 2D protein maps of the RBC cytosol and provides a helpful tool for future studies investigating disease- or storage-induced changes of the cytosolic RBC proteome.     

Thermal behaviour of mixed Sn and Ge phosphates

Pure and mixed Ge and Sn hydrogenphosphates, prepared either by refluxing in 8M H₃PO₄ or by hydrothermal treatment at 180° or 300°C, have been characterized in terms of chemical composition and thermal behaviour and also tested as catalysts in the 1-butene isomerization, in order to correlate acidic properties with preparation method. Solid solutions for every composition in this system are formed only when using the refluxing method, as proved by X-ray and TG-DTA data. The hydrothermal treatments are strongly influenced by the hydrolysability of the Ge phosphate: in almost all the samples, where Ge was present, GeOHPO₄ was identified on TG-DTA curves by the endothermic H₂O weight loss at 700°–800°C. The acidic properties of the various materials decrease as GeOHPO₄ content increases.     

Histochemical staining and quantification of dihydrolipoamide dehydrogenase diaphorase activity using blue native PAGE

Mammalian mitochondrial dihydrolipoamide dehydrogenase (DLDH, EC 1.8.1.4) catalyzes NAD(+)-dependent oxidation of dihydrolipoamide in vivo and can also act as a diaphorase catalyzing in vitro nicotinamide adenine dinucleotide (reduced form) (NADH)-dependent reduction of electron-accepting molecules such as ubiquinone and nitroblue tetrazolium (NBT). In this paper, we report a gel-based method for histochemical staining and quantification of DLDH diaphorase activity using blue native PAGE (BN-PAGE). Rat brain mitochondrial extracts, used as the source of DLDH, were resolved by nongradient BN-PAGE (9%), which was followed by diaphorase activity staining using NADH as the electron donor and NBT as the electron acceptor. It was shown that activity staining of DLDH diaphorase was both protein amount- and time-dependent. Moreover, this in-gel activity-staining method was demonstrated to be in good agreement with the conventional spectrophotometric method that measures DLDH dehydrogenase activity using dihydrolipoamide as the substrate. The method was applied to determine levels of DLDH diaphorase activity in several rat tissues other than the brain, and the results indicated a similar level of DLDH diaphorase activity for all the tissues examined. Finally, the effects of thiol-reactive reagents such as N-ethylmaleimide (NEM) and nitric oxide donors on DLDH diaphorase activity were evaluated, demonstrating that, with this method, DLDH diaphorase activity can be determined without having to remove these thiol-reactive reagents that may otherwise interfere with spectrophotometric measurement of DLDH dehydrogenase activity. The gel-based method can also be used as a means to isolate mitochondrial DLDH that is to be analyzed by mass spectral techniques in studying DLDH post-translational modifications.     

Urine protein quantification in stacking gel by SDS‐PAGE

Urine total protein concentration is usually measured by the pyrogallol red‐molybdate (PRM) assay in clinical laboratories, but it is often subject to sample interference. Here, we introduce a stacking gel‐based method for accurate protein quantitation. In this method, the urine protein samples are run into the stacking gel by SDS‐PAGE where it is concentrated into a single band, and then quickly stained by 0.001% Coomassie at high temperature. High correlations were found between the BSA and urine protein standards (R² = 0.997 and 0.990, respectively). Addition of 80 ng urine protein standard into each of the ten clinical urine specimens with questionable PRM results yielded the expected increase in the results by this method. Comparison of the PRM method and with the gel quantitation approach on about 60 clinical urine samples demonstrated a general consistency between the results (R² = 0.825), but in PRM samples with lower protein concentration showed more variations. Overall, the stacking gel method might be a good alternative for clinical urine samples with suspicious protein concentration results.     

Reactions of some acid phosphates and thiophosphites with thiocyanatoalcohols

Thiocyanatoalcohols react with some acid alkylene glycol phosphites and thiophosphites in the presence of Et₃N to give the corresponding hydroxyalkyl alkylene glycol thiophosphates or hydroxyalkyl dithiophosphates. The structure of the latter compounds determines their subsequent conversions.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. l, pp. 234–235, January, 1996.     

The use of cesium dibenzyl and diphenyl phosphates for stereoselective synthesis of glycosyl phosphate derivatives

Peracetates of β-glycosyl dibenzyl phosphates are formed efficiently in the reaction of cesium dibenzyl phosphate with peracetyl-α-glycosyl nitrates derived froml-fucopyranose,d-galactopyranose, and 2-azido-2-deoxy-d-galactopyranose or with tri-O-acetyl-α-l-fucopyranosyl bromide. On the contrary, the reaction of the above-mentioned glycosyl nitrates with cesium diphenyl phosphate leads to thermodynamically more stable α-glycosyl diphenyl phosphatevia intermediate formation of the corresponding β-anomers. Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1924–1928, November, 2000.     

Formation of polypyrrole chains in alumina and chromia-pillared layered phosphates

The reaction of gaseous pyrrole (pyr) with Cu²⁺ exchanged alumina- and chromia-pillared -tin and -zirconium phosphates has been investigated. Preliminary exchange with Cu²⁺ reveals differences in ordering in the two types of oxide-pillared materials, ascribed to differences in precursor insertion during their preparation. In both oxide-pillared types, the pyr rapidly polymerises in the pores (not on the surface). Optical spectra and XPS evidence point to the presence of more than one type of pyr polymer, and hence of a porous system. The optical properties are typical of mixed neutral and bipolaron states with the presence of low-oxidation level polypyrrole. Based on similarities in optical properties with zeolite analogues, it is suggested that the starting materials contain porous systems similar to both zeolite-Y and mordenite present together. As for zeolite-Y and mordenite analogues, the materials have negligible conductances ( < 10^{–9 –1} cm^–1), which is ascribed to the presence of only short polymeric pyr units.     

Separation of fluorescent phosphatidyl inositol phosphates by CE

Phosphatidyl inositol 4,5-bisphosphate (PIP2) and phosphatidyl inositol 3,4,5-trisphosphate (PIP3) labeled with 4,4-difluoro-5,7-dimethyl-4-bora-3a,4a-diaza-s-indacene-3-propionic acid (BODIPY FL) on the acyl chain or a phosphatidyl ethanolamine head group were separated by CE with LIF detection. Several methods and capillary-coating procedures were tested for the separation of these phosphatidyl inositol phosphates (PIPs) at 20 degrees C. Separation of the PIPs in less than 20 min with excellent resolution was achieved using a buffer containing sodium deoxycholate (SDC), 1-propanol, MgCl2 and the polymer coating reagent, EOTrol LR. The efficiency of the optimized method was as high as 1.3x10(5) plates. The dependence of the separation on the concentration of 1-propanol, SDC, and MgCl2 was determined. The separation of PIP2 and PIP3 was primarily due to differential binding of the lipids to Mg2+ rather than to different solubilities in the micellar phase. The role of the SDC was to prevent adsorption of the hydrophobic lipids to the capillary wall and thus enhance the efficiency. The fluorescent PIPs are of value for both in vitro and in vivo assays of phospholipid metabolism. In particular, the use of these lipids with the optimized capillary-based separation will be of utility for drug screening as well as cell-based assays.     

A method for detecting explosives

Bombs concealed in luggage have threatened human life and property throughout the world's traffic. The plastic explosives could not be checked by the X-ray detecting device. A method has been tested in the present work for non-destructive detection of explosives. A neutron generator and relevant apparatus have been used as a tool to find explosives, regardless of the bomb's shape and the packing materials. It seems that this method is a promising one because of the strong transmission ability of both the incident and output specific radiations and low background.     

Native PAGE eliminates the problem of PEG-SDS interaction in SDS-PAGE and provides an alternative to HPLC in characterization of protein PEGylation

PEGylation of proteins has become an increasingly important technology in recent years. However, determination and characterization of the PEGylation products are problematic especially for the reaction mixture containing various modified proteins, unreacted PEG, and unmodified protein. A comparative study was carried out with two HPLC methods and two electrophoresis methods for characterization of the reaction mixture in PEGylation of HSA with PEG 5000, 10000, and 20000. RP-HPLC fails to give the correct information about the reaction of PEG 20000. Size-exclusion HPLC (SE-HPLC) produced very poor resolution on the PEG 5000 reaction. SDS-PAGE can run multiple samples of all PEGylation but the bands were smeared or broadened probably due to the interaction between PEG and SDS. On the other hand, native PAGE eliminates the problem of PEG-SDS interaction and provides better resolutions for all samples. Various PEGylated products and unmodified protein migrate differentially in native PAGE under nondenatured conditions. The results demonstrated that native PAGE could be a good alternative to HPLC and SDS-PAGE for the analysis of PEG-protein conjugates especially for characterization of the PEGylation mixture.