摘要:

A fast and simple flow injection chemiluminescence method for the determination of trace amounts of tetracyclines is proposed based on the chemiluminescence of the KMnO4- TCs redox reaction in acidic medium in the presence of a sensitizer, OP. The response to the concentration of tetracyclines is linear in the range of 1.00 to 1000 μg mL−1with a relative standard deviation < 2.3 % for determination of 50.0 μg mL−1of each antibiotic (n = 11). The detection limits for tetracycline, oxytetracycline and chlortetracycline are 0.40, 0.52 and 0.60 μg mL−1, respectively. The recommended method is suitable for automatic and continuous analysis and has been successfully tested for determination of tetracyclines in commercial formulations. The chemiluminescence intensity was found to be remarkably enhanced when in the presence of OP micellar system; possible reasons for this observed micellar induced enhanced chemiluminescence is given.

ISSN:0003-2719    

DOI:10.1080/00032719708006425

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Two methods were adopted for the analysis of Pefloxacin. The first was a spectrophotometric determination of the substance in 0.1N H2SO4measuring the absorbance at λ 276 nm. Concentrations adhering to Beer's law were from 2.0–10.0 μg ml−1.

ISSN:0003-2719    

DOI:10.1080/00032719708006426

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

A new, simple, precise, accurate and rapid RP- HPLC method has been developed for the simultaneous determination of Cephalexin and Carbocisteine from capsules, using 0.025 M monobasic sodium phosphate: acetonitrile (87:13, v/v) as a mobile phase, and a C8Shodex column as the stationary phase. Detection was carried out using a UV detector at 210 nm. The linearity range for Cephalexin and Carbocisteine were 50 - 300 μg/mL and 40 - 200 μg/mL, respectively. Assay values for Cephalexin and Carbocisteine were 99.46% (R.S.D. - 1.30%) and 99.22% (R.S.D.-1.34%) for Brand 1. and 99.71% (R.S.D. - 1.68%) and 99.43% (R.S.D. - 1.78%) for Brand 2, respectively.

ISSN:0003-2719    

DOI:10.1080/00032719708006427

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

A method is developed for simultaneous separation and determination of μg/L levels of Co(II), Cu(II) and Ni(II) in fresh water by precipitate flotation. The optimal conditions of the experimental procedure with hydrated iron(III) oxide and iron(III) tetramethylenedithiocarbamate as collectors were investigated. The pH interval of the working medium, within which Co(II), Cu(II) and Ni(II) can be successfully separated, was determined from the aspect of collectors and surfactant stability. The amounts of the elements investigated were determined by electrothermal atomic absorption spectrometry. The detection limit of the method is 0.15 μg/L for cobalt, 0.03 μg/L for copper and 0.79 μg/L for nickel.

ISSN:0003-2719    

DOI:10.1080/00032719708006428

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The fluorescence emission from the lithium/1,4-dihydroxyanthraquinone system shows a great enhancement in the presence of certain water-miscible solvents. This is justified from the donicity (nucleophilic properties) of the solvent that facilitates the solvation of the lithium cation in solution and the stabilization of an nondissociated ion-pair between the solvated lithium cation and the 1,4-dihydroxyanthraquinonate anion. A very sensitive analytical method was proposed for the spectrofluorimetric determination of lithium based on its reaction with 1,4-dihydroxyanthraquinone (quinizarin) in a dimethylsulfoxide medium (90%) and in presence of sodium hydroxide. The fluorescence is measured at an excitation wavelength of 602 nm and an emission wavelength of 670 nm and it is stable at 25°C at least 6 h. The calibration curve is linear over the concentration ranges of 2–40 μg/l of lithium in an aqueous matrix and 3–50 μg/l in a serum matrix; the RSD's in the determination of 20 μg/l of Li+were 2.6% and 3.2%, respectively. The proposed procedure was satisfactorily applied to the determination of lithium in drugs, dietetic products and human serum.

ISSN:0003-2719    

DOI:10.1080/00032719708006429

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The enantiomeric separation by high-performance liquid chromatography of underivatized non-protein amino acids was investigated by using a column packed with octadecylsilanized silica coated withN,S-dioctyl-D-penicillamine as a chiral ligand-exchange phase (Sumichiral OA-5000). Excellent to good separations of enantiomers were achieved with a variety of nonprotein amino acids carrying aliphatic or aromatic side-chains by optimizing the amount (0-20%, v/v) of the organic component (2-propanol) and the concentration (1-5 mM) of the complexing metal ion (Cu2+) in the hydro-organic eluent.

ISSN:0003-2719    

DOI:10.1080/00032719708006430

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The retention time of α-(1,1,3,3-tetramethylbutyl)phenyl ethylene oxide oligomer surfactants was determined on a porous graphitized carbon column (PGC) in eluents containing acetonitrile, methanol, ethanol, 2-propanol, tetrahydrofuran, dioxane and 2-ethoxyethanol as organic modifier. Linear relationships were calculated between the logarithm of the capacity factor and the concentration of organic modifier in the eluent. Ethylene oxide oligomers were well separated on the PGC column in acetonitrile-water eluent mixtures. Oligomers were not separated in eluents containing 2-propanol, tetrahydrofuran. dioxane and 2-ethoxyethanol as organic modifier. This result was explained by the supposition that the bulky organic modifiers occupy the active adsorption centers on the PGC surface decreasing in this manner the separation efficiency of the support.

ISSN:0003-2719    

DOI:10.1080/00032719708006431

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

ISSN:0003-2719    

DOI:10.1080/00032719708006414

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor