摘要:

The addition of 8-hydroxy quinoline (Oxine) to vanadium and nickel in oil product sample from Saudi Arabia has increased the efficiency of the extraction. An inductively coupled plasma mass spectrometer (ICP/MS) and standard addition method were used for determining concentrations of vanadium and nickel. Recoveries of added vanadium and nickel as oil soluble salts were made and found to be at (98–102%) and (98–104%) ranges, respectively, and the % relative standard deviation for five replicate samples were less than 4% in all cases.

ISSN:0003-2719    

DOI:10.1080/00032719308016801

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A highly sensitive and selective fluorescence quenching method was developed to determine chlorine with 2,3,7-trihydroxy-9-dibromo-hydroxy-phenylfluorone as fluoregenic reagent. In the presence of CTMAB, a red compound was produced, its maximum excitation wavelength is 495nm, its emission wavelength is 520nm. The detection limit is 0.10μg/25ml. The linear calibration range is 0.10–3.0μg/25ml. This method may be used for the determination of chlorine in water.

ISSN:0003-2719    

DOI:10.1080/00032719308016802

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Functional esters of calixarenes, which are phenolic metacyclophanes annulated by a single methylene bridge, are immobilised onto silica particles for use in the separation of alkali metal ions by high performance liquid chromatography with conductivity detection. The immobilisation of tetrameric and hexameric calixarene ethyl esters was carried out using the triethoxy silane derivatives of p-allylcalix[n]arene ethyl esters. At an injected concentration of 10−2M, optimum selectivity for Na ions was achieved using a mobile phase of 30% MeOH/H2O with the calix[4]arene ester stationary phase. A mixture of four alkali metal chlorides is shown on injection to give a clear separation of Na+from the other unresolved ions, the retention order being Na+» K+> Cs+> Li+= to.

ISSN:0003-2719    

DOI:10.1080/00032719308016803

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A linear bilogarithmic hyperbolic cosine method for evaluating acidity constants of two-step overlapping equilibria (H2R/HR/R) from spectrophotometric measurements, applicable in those cases in which the absorbance versus pH curve passes throughout a maximum or a minimum in the region of pH in which the intermediate species predominates, has been devised in this paper. In order to evaluate its usefulness the method has been applied to five systems previously described in the literature.

ISSN:0003-2719    

DOI:10.1080/00032719308016804

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

An experimental mixture design was used to study the effect of methanol, propanol and amyl alcohol on the paper chromatographic separation of several amino acids and amino acid hydroxamates. The results from this design are compared with results from previous experimental designs on the same system. In mixture design, the sum of the component fractions equal one. This property is responsible for the differences observed.

ISSN:0003-2719    

DOI:10.1080/00032719308016805

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

This is a scanned image of the original Editorial Board page(s) for this issue.

ISSN:0003-2719    

DOI:10.1080/00032719308016790

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor