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81.
Egbert Müller Judith Vajda Djuro Josic Tim Schröder Romain Dabre Tim Frey 《Journal of separation science》2013,36(8):1327-1334
An essential part of the modulation of protein‐binding capacity in hydrophobic interaction chromatography is the buffer‐salt system. Besides using “single” electrolytes, multicomponent electrolyte mixtures may be used as an additional tool. Both the protein solubility and the binding capacity depend on the position of a salt in the so‐called Hofmeister series. Specific interactions are observed for an individual protein‐salt combination. For salt mixtures, selectivity, recovery, and binding capacity do not behave like for the single salts that are positioned in between the two mixed components in the Hofmeister series, as the continuous correlation would suggest. Thus, finding strategies for mixed salts could potentially lead to improved capacities in hydrophobic interaction chromatography. Mixtures of ammonium sulfate, sodium citrate, sodium sulfate, sodium chloride, sodium acetate, and glycine were used to investigate the binding capacities for lysozyme and a monoclonal antibody on various hydrophobic resins. Resin capacity for two investigated proteins increases when mixtures consisting of a chaotropic and a kosmotropic salt are applied. It seems to be related to the rather basic isoelectric points of the proteins. 相似文献
82.
Chitrakara Hegde Arun M. Isloor Mahesh Padaki Hoong-Kun Fun 《Arabian Journal of Chemistry》2013,6(3):319-326
The present work describes about the synthesis and characterization of Polysulfone blend nanoporous membrane with nonwoven support. This Nonwoven support provides mechanical strength to membrane while filtration process and minimizes membrane fouling. Hence it helps in better membrane performance in terms of salt rejection, improved flux, thermal stability and fairly increases in proton conductivity. In this work we have used K.C.270 nonwoven material consisting of fine polyester fibers and has a thickness of below 110 μm. 相似文献
83.
A sample extraction and purification procedure that uses ammonium-salt-induced acetonitrile/water phase separation was developed and demonstrated to be compatible with the recently reported method for pesticide residue analysis based on fast extraction and dilution flow injection mass spectrometry (FED-FI-MS). The ammonium salts evaluated were chloride, acetate, formate, carbonate, and sulfate. A mixture of NaCl and MgSO4, salts used in the well-known QuEChERS method, was also tested for comparison. With thermal decomposition/evaporation temperature of <350 °C, ammonium salts resulted in negligible ion source residual under typical electrospray conditions, leading to consistent method performance and less instrument cleaning. Although all ammonium salts tested induced acetonitrile/water phase separation, NH4Cl yielded the best performance, thus it was the preferred salting out agent. The NH4Cl salting out method was successfully coupled with FI/MS/MS and tested for fourteen pesticide active ingredients: chlorantraniliprole, cyantraniliprole, chlorimuron ethyl, oxamyl, methomyl, sulfometuron methyl, chlorsulfuron, triflusulfuron methyl, azimsulfuron, flupyrsulfuron methyl, aminocyclopyrachlor, aminocyclopyrachlor methyl, diuron and hexazinone. A validation study was conducted with nine complex matrices: sorghum, rice, grapefruit, canola, milk, eggs, beef, urine and blood plasma. The method is applicable to all analytes, except aminocyclopyrachlor. The method was deemed appropriate for quantitative analysis in 114 out of 126 analyte/matrix cases tested (applicability rate = 0.90). The NH4Cl salting out extraction/cleanup allowed expansion of FI/MS/MS for analysis in food of plant and animal origin, and body fluids with increased ruggedness and sensitivity, while maintaining high-throughput (run time = 30 s/sample). Limits of quantitation (LOQs) of 0.01 mg kg−1 (ppm), the ‘well-accepted standard’ in pesticide residue analysis, were achieved in >80% of cases tested; while limits of detection (LODs) were typically in the range of 0.001–0.01 mg kg−1 (ppm). A comparison to a well-established HPLC/MS/MS method was also conducted, yielding comparable results, thus confirming the suitability of NH4Cl salting out FI/MS/MS for pesticide residue analysis. 相似文献
84.
《合成通讯》2013,43(22):3449-3454
ABSTRACT A series of substituted 5-oxo-1,2,3,4,5,6,7,8-octahydroquinoline derivatives have been synthesized from 5,5-dimethyl-1,3-cyclohexane-dione (dimedone) and 1,3-diaryl-2-propen-1-one in DMF at 80°C in the presence of ammonium acetate with high yields (64–98%), the structure of the product was confirmed by X-ray analysis. 相似文献
85.
Four-component, one-pot condensation of dimedon, thiophene-2-carbaldehyde, ammonium acetate, and numerous acetophenones yielded novel 2-aryl-4-thionylquinoline derivatives. The structures were characterized by 1H NMR, 13C NMR, IR, and elemental analysis. 相似文献
86.
M. Anil Kumar K. R. Kishore Kumar Reddy M. Veeranarayana Reddy C. Devendranath Reddy 《合成通讯》2013,43(13):2089-2095
An efficient and direct approach for the α-thiocyanation of ketones with α-hydrogens has been developed using ammonium thiocyanate as a thiocyanating agent and oxone as an oxidant in methanol. 相似文献
87.
《合成通讯》2013,43(24):4477-4482
Abstract Regioselective synthesis of α‐iodoacetates from alkenes, ammonium acetate, and iodine in acetic acid is reported. The reaction is facile, fast, environmentally, friendly, and cost effective. α‐Iodoacetates are obtained from both acyclic and cyclic alkenes in high yields ranging from 80–95% within 10–20 min. 相似文献
88.
Lennart Mårtensson Staffan Bergström Britt-Marie Svensson Lennart Mathiasson 《International journal of environmental analytical chemistry》2013,93(1):17-27
Different methods for treatment of leachate from a municipal solid waste (MSW) landfill were tested in a pilot plant. Raw leachate was pre-treated with aeration and sedimentation, followed by several parallel individual steps such as bioremediation, chemical oxidation, ozonation, and geo-bed filters. The efficiency of different treatment steps was evaluated according to one previously developed protocol, which includes measurements of several parameters such as conductivity, pH, nutrients, chloride, metals, organic compounds, and acute toxicity before and after a treatment step. The treatment steps which showed the highest efficiency towards organic pollutants in leachate were ozone treatment and chemical oxidation. The use of an adsorption filter, a geo-bed with a mixture of peat and bottom ash with ca 10% remaining carbon, also had good effects. A combination of pre-treatment and a geo-bed filter with peat and carbon ash gave the best overall treatment results when water-quality parameters such as total organic carbon and ammonia-nitrogen were also considered. 相似文献
89.
Susana Meseguer-Lloret Carmen Molins-Legua Pilar Campins-Falco 《International journal of environmental analytical chemistry》2013,93(7):475-489
A selective and sensitive method based on the ammonium derivatisation with o -phthaldialdehyde (OPA) and N -acetyl-cysteine (NAC) has been developed for ammonium determination in real water samples. The proposed procedure has been compared with ammonium reference methods such as Nessler reagent method and ammonium selective electrode. All procedures have been chemometrically tested and compared in terms of the main analytical properties. These procedures have been used to determine ammonium in unknown water samples. The OPA-NAC reagent method does not present any systematic error (proportional or constant), while Nessler reagent presents both of them for some samples assayed. The ammonium selective electrode is free of corrigible systematic errors, however presents amine interference. The OPA-NAC ammonium method is able to achieve a detection limit (LOD) of 0.07 mg/L in the sample, with a linear dynamic range up to 1.4 mg/L of ammonium. 相似文献
90.
The selective oxidation of aromatic and aliphatic organosulfides with H2O2/H2O catalyzed by metal free ammonium salts has been explored. Reactions were performed using 2.5–5 mol % of catalyst loadings, isolating the corresponding sulfoxides in good to excellent yields (75–93%) and high selectivity. 相似文献