Catechol violet

Colorimetric methods always include hafnium. Most methods employ a separation step such as solvent extraction. The three reagents used successfully are 8-hydroxyquinoline (88), alizarin red S (89), and catechol violet (90). 

In an early method Kodama and Tsubota [567] determined tin in seawater by anion exchange chromatography and spectrophotometry with catechol violet. 

After adjusting to 2 mol 1 1 in hydrochloric acid, 500 ml of the sample is adsorbed on a column of Dowex 1-XS resin (Cl form) and elution is then effected with 2 M nitric acid. The solution is evaporated to dryness after adding 1M hydrochloric acid, and the tin is again adsorbed on the same column. Tin is eluted with 2 M nitric acid, and determined in the eluate by the spectrophotometric catechol violet method. There is no interference from 0.1 mg of aluminium, manganese, nickel, copper, zinc, arsenic, cadmium, bismuth, or uranium any titanium, zirconium, or antimony are removed by ion exchange. Filtration of the sample through a Millipore filter does not affect the results, which are in agreement with those obtained by neutron activation analysis. 

Wet oxidation of samples of biological origin with a mixture of nitric acid and perchloric acid is a common procedure that may be problematic in certain cases. An alternative procedure for sample preparation is irradiation with a strong UV source. Acidified samples of hair (0.1 g) containing about 2 pg Pb and other trace elements, were irradiated for 3 h with a 500 W source a buffer (pH 5.5) and a small amount of catechol violet (9) were added, and the complex of the dye with the trace elements was determined polarographically RSD ca 5% for Pb95. 

Solochrome black T, solochrome dark blue at 520 nm [109] W(VI)-catechol violet at 650 nm [110] o-Hydroxy-quinolphthalein at 525 nm [111]... 

At high pH values, the first electron transfer process occurs without protonation so that a single irreversible one-electron process is initially observed. The resulting catechol violet radical anion is then reduced (66) at a more negative potential in an EC reaction (67) (resulting in the observation of a second reduction wave), in which the dianion is doubly protonated ... 

Sn Asbestos, cellulose Sn-catechol-complex from catechol violet Foodstuff (organotin stabilizer) Photometry 80 ppm 119)... 

Gallium forms a three-component complex with Catechol Violet and quinine (having an absorption maximum at 680 nm) which may be used for its photometric determination. ... 

The reaction of metal species with added colorimetric ligand has also been utilized to gain speciation information. A classic example is the use of pyro-catechol violet as a spectrophotometric reagent to determine labile monomeric (fast reacting) and organic aluminum species. 

Domininguez O and Arcos MJ (2000) Speciation of chromium by adsorptive stripping voltammetry using pyro-catechol violet. Electroanalysis 12 449—458. 

Numerous techniques have been described to evaluate total tin on ashed or wet mineralized biological, food, or environmental media by colorimetric determination of tin(IV) with phenyl-fluorone [51-53], catechol violet [54-59], salicylaminothiophenol [60], hematoxylin [61], quercetin [62,63], dithizone [64], or dichloro-8-quinolinol [65]. In general, these analytical reagents are nonspecific and best suited to samples where tin values in materials are not lower than about 0.2 ppm. A better sensitivity may be obtained with fluorimetric methods using morin [66,67] or diacetylmonoxime nicotinylhydrazone [68]. 

Simpson and Currell [32] used butanol - glacial acetic acid (97 3) as the mobile phase and sprayed the developed plate with catechol violet solution followed by irradiation of the plate for 10 minutes with UV radiation and a respray with catechol violet solution to detect the separated compounds as blue spots. This procedure can be applied to the detection of organotin compounds in PVC using a preliminary extraction of the additives from 5 g polymer with diethyl ether for eight hours. Ether is removed by evaporation and ethanol added to precipitate polymer which is then filtered off. If more accurate quantitative results are required it is necessary to perform an extraction additional to the diethyl ether extraction by using an azeatrope of carbon tetrachloride - methanol (2 1) for a further four hours. 

The spots are visualised by spraying the layers with a solution of dithizone in chloroform or by exposure to UV-radiation for 30 min and subsequently spraying with catechol violet solution. Organo-tin derivatives of the four alkylation stages can be separated and amounts down to 1 p.g can be detected. The toxicologically important distinction... 

Polyvinyl chloride Vinegar, orange juice Organotin, dioctyltin 5,5 te(isoactyl mercapto acetate) Spectrophotometrically in catechol-violet complex [89]... 

Polyvinyl chloride Beer B/s(zethylhexyloxy carbonyl) methyl thio dioctyl tin Spectrophotometrically as catechol violet complex [90, 91]... 

Catechol violet (I) forms colored complexes with many ions but only the complexes with boric acid, germanium, niobium and tantalum are unaffected by EDTA. At pH 6-7 boric acid forms a reddish complex, germanium purple and niobium and tantalum blue-violet. At pH 1 and in the presence of sufficient EDTA, only tantalum forms a colored complex. ... 

Procedure. To one drop of the test solution is added one drop of cone, hydrochloric acid, one drop of a saturated solution of EDTA (free acid) and one drop of a 0.1 % aqueous solution of catechol violet. A blue-violet color indicates the presence of tantalum. 

G. Organyl Tin Ions (1) Test with catechol violet ... 

Mono- and dialkylated or arylated tin salts react in the same way as inorganic tin compounds with catechol violet to form intense blue chelates. Derivatives of tin containing three or four organic groups do not react... 

Procedure. The paper chromatogram or filter paper on which the test solution has been spotted is sprayed with a solution of catechol violet. Mono- or dialkyl or aryl tin compounds are indicated by blue stains. 

Test with boric acid-catechol violet complex... 

The red-violet complex of boric acid and catechol violet reacts selectively with yttrium salts to form a blue complex of yttrium and catechol violet. 

Procedure. To one drop of the sample on a spotting plate is added one drop of ammonium acetate bujffer (pH 8.7), one drop of 0.1% catechol violet solution, 1 drop of 3% boric acid solution, and 1 drop of 3% hydrogen peroxide to mask cerium. A blue color indicates the presence of yttrium. 

By using ion exchange resins, 0.01 y Zr can be detected. A few granules of Amberlite IRA-411 (sulfate form) are mixed on a porcelain tile with 1 drop of 1 iV sulfuric acid-1 M K2SO4 (3 1), 1 drop of 0.5 % aqueous catechol violet solution and 1 drop of an acid (0.1 N) solution of the sample. A deepening of the orange-yellow color of the resin or the appearance of a blue color indicates the presence of Zr. Interference is caused by Bi, Hg, Al, Cu and Fe. ... 

Tantalum Catechol violet Pyrogallol-4-sulfonic acid and — 467... 

Complex of catechol violet with boric acid 5 610... 

Xylenol orange + CTAB bromide Catechol violet + CTAB bromide Pyrocatechol violet (and + CTAB bromide) Gallein... 

Among triphenylmethane derivatives, we ean mention Catechol violet or pyrocatechol violet ... 

Organotin thioacids and thiols TLC on kielselgel G, elution with hexane - glacial acetic acid and detection with catechol violet 97... 

Organotin stabilizers TLC on kieselgel GF 254, elution with butanol-glacial acetic acid, detection with catechol violet and UV irradiation 47... 

Catechol violet, 0.1 per cent, w/v solution in 95 per cent ethanol. 

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