Pyridylazo resorcinol

OPTICAL DENSITY DIFFERENTIATION FOR THE MIXTURES OF Cu, Zn, Co, Ni COMPLEXES WITH 4-(2-PYRIDYLAZO)-RESORCINOL... 

The differentiation of analytical signal in the photometry enables one to use non-specific reagents for the sensitive, selective and express determination of metals in the form of their intensively coloured complexes. The typical representative of such reagents is 4-(2-pyridylazo)-resorcinol (PAR). We have developed the methodics for the determination of some metals in the drinking water which employ the PAR as the photometric reagent and the differentiation of optical density of the mixture of coloured complexes by means of combined multiwave photometry and the specific destmction of the complexes caused by the change of the reaction medium. 

Concentration limits of the diphosphate-ion, admissible to determination of magnesium and cobalt, manganese and cobalt, zinc and cobalt by spectrophotometric method with application of the l-(2-pyridylazo)-resorcinol (PAR) are presented. Exceeding maintenance of the diphosphate-ion higher admissible supposes a preliminary its separation on the anionite in the H+-form. The optimum conditions of cobalt determination and amount of the PAR, necessary for its full fastening are established on foundation of dependence of optical density of the cobalt complex with PAR from concentration Co + and pH (buffer solutions citrate-ammoniac and acetate-ammoniac). 

Monien and Stangel [598] studied the performance of a number of alternative chelating agents for vanadium, and their effect on vanadium analysis, by atomic absorption spectrometry with volatilisation in a graphite furnace. Two promising compounds were evaluated in detail, namely 4-(2-pyridylazo) resorcinol in conjunction with tetraphenylarsonium chloride and tetramethylenedithiocar-bamate. These substances, dissolved in chloroform, were used for extraction... 

Determination of Pb(II) ion by classical or reversed FIA consists of a preconcentration step either on columns packed with a chelating sorbent (PC-FIA) or on a mercury film, followed by spectrophotometric determination of the complex with 4-(2-pyridylazo)resorcinol (11, kmax 518 nm) in borate buffer solution RSD 3-6% at 0.01-1 pM. End analysis by ASV was also applied99. 

Determination of organolead metabolites of tetraalkyllead in urine can be carried out after solid-phase enrichment and end analysis using reversed-phase HPLC with chemical reaction detector and by LC-MS (thermospray127). The chemical derivation consists of conversion to the dialky Head form, as shown in reaction 1, followed by complex formation with 4-(2-pyridylazo)resorcinol (11) and spectrophotometic measurement at 515 nm128. 

A rare example of substitution kinetics at mercury(II) is provided by the adaptation of replacement of coordinated 4-(2-pyridylazo)resorcinol by l,2-cyelohexanediamine-./V,./V,./V,./V,-tetraacetate to analysis for sulfite or thiosulfite (324). 

Simon et al. [47] developed a photometric flow-through sensor for the determination of zinc using a transparent PVC membrane accommodating a lipophilized ligand, viz. l-octadecyloxy-4-(2-pyridylazo)resorcinol, a water-insoluble derivative of PAR. The mechanism by which the analyte is retained in the membrane and eluted from it is similar to a liquid-liquid extraction... 

Any dialkyl lead present was determined spectrophotometrically as the dialkyllead 4(2-pyridylazo)resorcinol (P.A.R.) complex at pH 9. Trialkyl lead does not form a complex with P.A.R. therefore its concentration was obtained by conversion to the dialkyl lead form in iodine monochloride solution followed by determination as the P.A.R. complex. Any inorganic lead in solution was... 

The interaction of metallochromic indicators (Section 10.6.4) with metals has received a lot of attention since the resulting complexes are often solvent extractable. C. Woodward and H. Freiser73 have examined complexes of metals with sulfonated azo dyes with a view to their extraction by Aliquat-336. Vanadium in sea water can be determined at the 2 p.p.b. level by complexation with PAR (4-(2-pyridylazo)resorcinol) in the presence of CDTA and extracting the anion so formed into Zephiramine (tetradecyldimethylbenzylammonium chloride).74 The field has been reviewed up to 1971 by Ueno.2... 

Presence of HCN indicated by color change of 4-(2-pyridylazo) resorcinol-palladium in carbonate-bicarbonate buffer solution from intense red to yellow (Carducci et al., 1982). 

Improvements in separations ability offered by the Dionex HPIC-CS5 column, which exhibits both anion and cation exchange capacity, have allowed the determination of ten metal ions in a single injection with a pyridine-2,6-dicarboxylic acid (PCDA) eluent (Fig. 2.3). The post-column reagent used in the detection scheme was 4-(2-pyridylazo) resorcinol. 

Uranium has been determined in process liquids by ion chromatography using an ammonium sulphate sulphuric acid element. Uranium was determined in the eluant. Uranium was determined in the eluate spectrophotometrically at 520 mm as the 4(-2-pyridylazo) resorcinol complex [36],... 

Hazardous materials in trace amounts, such as metallic ions, find their way into the water system. It is necessary to be able to detect these materials in situ and in real time. Recently (12), such a method was found involving the SERS technique using optical fibers. The technique monitors the ions in aqueous solutions, measuring the changes in the Raman spectra of indicators, which form complexes with the metallic ions. The indicators used were Eriochrome Black T (EBT), 4-(2-pyridylazo)resorcinol (PAR), cresol red, methyl red and 4-pyridinethiol. 

Srijaranai, S. et al. Flow-injection in-line complexation for ion-pair reversed phase high performance liquid chromatography of some metal -(2-pyridylazo) resorcinol chelates. Talanta 2006, 68, 1720-1725. 

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