RESUMO
The distribution behavior of 8-quinolinols (HQ) in organic and acidic aqueous solutions (or alkaline solutions) was electrochemically examined by current scan polarography and chronopotentiometry. It follows from the results that the half wave potential of the observed polarographic waves, corresponding to the Faradaic transfer of quinolinolium ions (or oxinate ions) formed in the aqueous solution after distribution of quinolinols is dependent on the dissociation constant of H(2)Q(+) (or HQ) and the pH of the aqueous solution, but independent of the distribution constant of 8-quinolinols.
RESUMO
Current-scan polarography at the ascending-water electrode (AWE) was used to examine the electrochemical behavior of HTTA and La(3+), both in the absence and presence of neutral ligands, TOPO or MBDPO, and the light this sheds on the mechanism of extraction of lanthanides with HTTA, as well as the role played by mixed-ligand chelate formation.
RESUMO
Brilliant Green is used as the stationary phase in the ion-pair chromatography of butanoic, pentanoic, octanoic and lauric acids, with hexane-dichloromethane as eluent.
Assuntos
Eletrodos , Potássio/análise , Valinomicina , Métodos , Potássio/sangue , Água do Mar/análiseRESUMO
The stability constants of cadmium complexes of compounds related to dithizone are reported. Substitution in the ortho position lowers the stability constant. It is probable that this is a consequence of deviation from coplanarity of the phenyl and chelate rings.
RESUMO
A survey has been made of analytically useful extractable ion-pair complexes that are formed by the use of a series of metallochromic indicator-metal complexes in conjunction with quaternary ammonium ions. The reagents were o,o'-dihydroxyazo dyes and azo-oxines.
RESUMO
The structure of zinc(II) dithizonate has been determined by X-ray analysis. The co-ordination round the zinc is slightly distorted tetrahedral and the proximal phenyl rings have been shown to be almost coplanar with the chelate rings.
RESUMO
The mixed ligand nickel-dithizone-phenanthroline complex provides a sensitive method for determination of nickel and also permits evaluation of the extraction constant for nickel dithizonate. The value log K(ex) = -0.7 was obtained, in agreement with a value of -0.2 obtained by others, and in contrast to an earlier value of -2.9. The addition of phenanthroline substantially increases the rate of extraction.
RESUMO
Absorption and fluorescence emission spectra of 2',7'-bis (acetoxymercuri)-fluorescein (AMF) at various pH values and in the presence of mercury-complexing agents such as mercaptoacetic acid, cyanide and iodide have been employed in the study of the reactions of AMF with these ligands. The findings have been applied to the development of methods for the determination of submicrogram quantities of iodide and cyanide with a precision of better than 10%.
RESUMO
A method is proposed for the titrimetric determination of BAL with zinc solution and Eriochrome Black T (EBT) as indicator. It is based on the difference of the stabilities of the Zn(BAL)a and Zn-EBT complexes. The accuracy of the method is very good and the interference of diverse mercaptans is limited to those compounds forming zinc complexes more stable than the Zn-EBT complex.
RESUMO
Addition of phenanthroline to nickel dithizonate in chloroform results in a mixed ligand complex, NiDz(2)phen, the high molar absorptivity of which (49.1 x 10(3)) results in a colorimetric estimation of nickel that is significantly more sensitive than any other method.
