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Malachite green test

Comments Commercially available. Provides indirect quantitative analysis and a green color. [Pg.91]

Comments Commercially available. Provides direct quantification based on the consumption of PDAM using UV-visible spectroscopic measurements and fluorescent beads under 350-360 nm UV illumination. [Pg.91]


Detecting the presence of small, even invisible, amounts of blood is routine. Physical characteristics of dried stains give minimal information, however, as dried blood can take on many hues. Many of the chemical tests for the presence of blood rely on the catalytic peroxidase activity of heme (56,57). Minute quantities of blood catalyze oxidation reactions between colorless materials, eg, phenolphthalein, luco malachite green, luminol, etc, to colored or luminescent ones. The oxidant is typically hydrogen peroxide or sodium perborate (see Automated instrumentation,hematology). [Pg.487]

In the malachite green procedure, 10 ml of the sample solution containing up to 0.7 xg phosphorus as orthophosphate was transferred into a 25 ml test tube. To this solution was added 1 ml each of 4.5 M sulfuric acid and the reagent solution. The solution was shaken with 5 ml of a 1 3 v/v mixture of toluene and 4-methylpentan-2-one for 5 min. After phase separation, the absorbance of the organic phase was measured at 630 nm against a reagent blank in 1 cm cells. [Pg.98]

Test Malachite green (MG)16 Application Detection of carboxylic acids... [Pg.32]

Notes. We found this test to be highly reproducible, but the test time is crucial to obtaining accurate results. We observed false positives when resin samples were left in the malachite green solution for more than 15 min, and a loss of color when green beads are left in MeOH for more than 15 min. [Pg.32]

Fuchsitt test Dilute solutions of triphenylmethane dyestuffs, such as fuchsin (for formula, see Section IV. 15, reaction 9) and malachite green, are immediately decolourized by neutral sulphites. Sulphur dioxide also decolourizes fuchsin solution, but the reaction is not quite complete nevertheless it is a very useful test for sulphur and acid sulphites carbon dioxide does not interfere, but nitrogen dioxide does. If the test solution is acid, it should preferably be just neutralized with sodium hydrogen carbonate. Thiosulphates do not interfere but sulphides, polysulphides, and free alkali do. Zinc, lead, and cadmium salts reduce the sensitivity of the test, hence the interference of sulphides cannot be obviated by the addition of these salts. [Pg.304]

This test is based on bromide s redox characteristic and the ability of bromine to give a color reaction with a solution of decolorized fuchsin. This reagent is also known as malachite green and by many authors as Schiff s reagent, owing to its use in a determination of aldehydes discovered by H. Schiff. [Pg.36]

The above hypercrosslinked samples have been tested under identical conditions for their ability to extract from aqueous solutions three synthetic organic dyes Malachite Green (MG), Methylene Blue (MB), and Direct Bordeaux (DB) ... [Pg.413]

Another AOAC approved method for sulfites in meat is the qualitative test based on decolorization of malachite green solution when mixed with a sample containing sulfites. This may be used to screen samples prior to quantitative determination as described above. [Pg.1556]

Two other methods have been approved by AOAC for determination of sulfites in food. One is a quantitative assay based on malachite green decolorization using flow injection analysis. Sulfite is released from a sample slurry with alkali, then the test stream is acidified to produce sulfur dioxide gas which diffuses across a Teflon membrane into a flowing stream of malachite green, and the extent of decolorization is measured at 615 nm. The other method is based on ion exclusion chromatography with sulfur dioxide being released by alkali extraction, and the diluted filtrate is injected onto an anion exclusion column linked to an electrochemical detector. [Pg.1556]

Another test for phosphorus (as phosphate) is based on the fact that the phosphomolybdates (and phosphotungstates) form deeply coloured insoluble lakes with triphenylmethane dyes such as methyl violet or malachite green (Chapter 12.8). The procedure is as follows a drop of test solution is placed on a filter paper which is then sprayed with a 1% solution of methyl violet. After about half a minute the paper is then sprayed with a solution of acidified ammonium molybdate and a blue spot develops. This method is sensitive to 1 part in 500,000. [Pg.1330]

Fessard, V. Godard, X. Huet, S. Mourot, A. Poul, J. M. Mutagenicity of malachite green and leucomalachite green in in vitro tests. J. Appl. Toxicol. 1999,19,421 30. [Pg.214]

Other tests for cerium v compounds [a) Leuco malachite green is oxidized to malachite green by Ce(OH)4, which is formed from Ce(OH)8 by autoxidation. Interference due to Mn(OH)2, Co(OH)2, Tl(OH)a and AgaO, which react in the same way, may be prevented... [Pg.175]

Procedure. One drop of the test solution, which may be neutral or 0.1 AT with respect to hydrochloric acid, and which must be free from interfering substances, is mixed on a spot plate with a microdrop of 1 % titanous chloride solution and a microdrop of a 0.005% water solution of malachite green. Depending on the concentration of tungsten, the solution becomes colorless (very pale violet) more or less rapidly. With small quantities of tungsten, it is well to make a blank test. [Pg.497]

Sulfite, Test with malachite green, see page 447. [Pg.610]

Dialkyl derivatives of aniline, diphenylamine, and carbazole, when melted with benzotrichloride and fused zinc chloride, yield triphenylmethane dyes of the malachite green type. Phenols, diphenyl sulfide, and indole react as well, but the dyes obtained are red. This test can be completed by identifying the triphenylmethane dye formed by paper chromatography (22) to differentiate, for example, dimethyl- and diethylaniline. A similar reaction results from melting the sample with oxalic acid. This reaction leads to the formation of blue dyes, characteristic of the derivatives of diphenylamine and carbazole (23). [Pg.325]


See other pages where Malachite green test is mentioned: [Pg.91]    [Pg.91]    [Pg.324]    [Pg.282]    [Pg.23]    [Pg.53]    [Pg.1091]    [Pg.234]    [Pg.441]    [Pg.67]    [Pg.494]    [Pg.20]    [Pg.324]    [Pg.1110]    [Pg.156]    [Pg.73]    [Pg.339]    [Pg.641]    [Pg.150]    [Pg.763]    [Pg.132]    [Pg.133]    [Pg.140]    [Pg.447]    [Pg.496]    [Pg.390]    [Pg.247]    [Pg.450]    [Pg.182]   
See also in sourсe #XX -- [ Pg.91 ]




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