摘要:

Silica gels, chemically modified with mono, di, tri and tetramine (I - IV), were synthesized. The monoamine (I) was produced directly via the reaction of silica gel with 3-aminopropyltrimethoxysilane. The diamine (II), triamine (III) and tetramine (IV) were produced through the reaction of ethylenediamine (EDA), diethylenetriamine (DETA) and triethylenetetramine (TETA) with 3-chloropropyltrichloromethane modified silica gel, respectively. The sorption properties of the phases (I - IV) toward Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Pb(II) were investigated at different pH-values based on the batch equilibrium technique, The, metal uptake capacities (mmol/g) were determined and discussed in terms of the structure of the aliphatic amines and the increasing number of nitrogen donor atoms. The metal capacity values demonstrate the higher efficiency of phases III and IV than phases I and II for preconcentration of such metal ions. Moreover, the use of phases III and IV for selective extraction of Cu(II) and Ni(II) is promising.

ISSN:0003-2719    

DOI:10.1080/00032719708001690

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

An artifactual signal splitting was observed for acetic acid during the capillary zone electrophoresis of wine acids. Further study revealed that other comparably weak acids, propionic and butyric, show a similar split. Stronger carboxylic acids, formic, tartaric, malic, citric, and lactic acids showed no artifactual signal splits under the analysis conditions. Succinic acid showed intermediate behavior. The signal splitting could be eliminated by reducing the sample size and/or by employing the background electrolyte as the diluant.

ISSN:0003-2719    

DOI:10.1080/00032719708001691

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

A quantitative chemometric approach, iterative target transformation factor analysis (ITTFA), was applied to the simultaneous determination of mixtures of four food colorants (Amaranth, Sunset Yellow. Tartrazine and Ponceau 4R) by adsorptive voltammetry. The conventional and first-derivative voltammograms of the quaternary mixtures were used to perform the optimization of the calibration procedure by the ITTFA models. The proposed method was applied satisfactorily to the determination of a set of synthetic quaternary mixtures of colorant in phosphate/citric acid buffers (pH 5.7) and acceptable results were obtained. No significant advantages were found with the application of derivative technique in this voltammetric work.

ISSN:0003-2719    

DOI:10.1080/00032719708001692

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

ISSN:0003-2719    

DOI:10.1080/00032719708001693

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

ISSN:0003-2719    

DOI:10.1080/00032719708001694

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

ISSN:0003-2719    

DOI:10.1080/00032719708001679

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor