Chromotropic acid test

Thaliracebine (324), C39H44N207, amorphous, mp 83-84°C, [a] >6 +121° (c 0.28, MeOH), was isolated from Thalictrum minus Race B. The UV max of 278 nm shows no change in acid or alkali, in accord with a nonphenolic bis tetrahy-dro base. A positive chromotropic acid test confirmed the NMR evidence (8... 

Chromotropic acid test A red colouration, best seen by transmitted light, is given by chromates. For details, see under Chromium, Section III.24, reaction 8d. 

Formaldehyde-chromotropic acid test Formic acid, H.COOH, is reduced to formaldehyde H.CHO by magnesium and hydrochloric acid. The formaldehyde is identified by its reaction with chromotropic acid (see Section III.24, reaction 9d) in strong sulphuric acid when a violet-pink colouration appears. Other aliphatic aldehydes do not give the violet colouration. 

Chromium, 58 Chromonar, 467 Chromonar hydrochloride, 467 Chromophores, 222 Chromosorb 102,178 Chromosorb G, 179 Chromosorb P, 179 Chromosorb W, 179 Chromotropic Acid (test), 131 Chronogest, 623 Chrysazin, 507 Chryzacin, 507 Ciatyl, 484 Ciba-1906, 1014 Cibalith-S, 708 Cibazol, 995 Cicatrene, 369 Cicatrex, 369 Cicatrin, 369 Ciclobarbital, 656 Ciclosterone, 1003 Cicutine, 493 Cidomycin, 637 Cillimycin, 706 Cimetidine, 467 Cincain, 468... 

Polyoxymethylenes or polyacetals (polymers of formaldehyde or trioxane) produce formaldehyde on heating. The chromotropic acid test for formaldehyde is positive (see Section 6.1.4). 

Lead Determine as directed for Method I in the Atomic Absorption Spectrophotometric Graphite Furnace Method under Lead Limit Test, Appendix IIIB, using a 10-g sample. Methanol Transfer 1 drop of sample to a test tube, add 1 drop of 1 20 phosphoric acid and 1 drop of 1 20 potassium permanganate solution mix and allow to stand for 1 min. Add, dropwise, 1 10 sodium bisulfite solution until the permanganate color disappears. If a brown color remains, add 1 drop of the phosphoric acid solution. Add 5 mL of freshly prepared chromotropic acid TS to the colorless solution, and heat it in a water bath at 60° for 10 min. No violet color appears. 

Place a drop of the test solution in a semimicro test-tube, add a drop of the reagent, a drop of dilute nitric acid (1 1), and dilute to about 2 ml. Chromates give a red colouration this is best observed with a white light behind the tube. The reagent consists of a saturated solution of chromotropic acid in water. Concentration limit 1 in 5,000. 

Place a drop or two of the test solution in a semimicro test-tube, add a drop or two of dilute hydrochloric acid, followed by magnesium powder until the evolution of gas ceases. Introduce 3 ml sulphuric acid (3 vol. acid-I-2 vol. water) and a little solid chromotropic acid, and warm to 60°C. A violet pink colouration appears within a few minutes. 

The reagent consists of a saturated solution of chromotropic acid. The reagent does not keep well, hence it is preferable to impregnate drop-reaction paper with the reagent solution and allow the paper to dry in the air. The impregnated papers are stable for several months. In use, a drop of the test solution and a drop of m H2S04 are placed upon the impregnated paper a purplish-pink colour results. 

Chromotropic acid (saturated). To 0-1 g chromotropic acid (1,8-dihydroxy-naphthalene-3,6-disulphonic acid sodium salt) C, 0H6O8S2Na2 add 5 ml water, mix thoroughly, and use the pure supernatant liquid for the tests. 

Miscible with water and ethanol immiscible with chloroform and ether. Colour Tests. Chromotropic Acid—red. 

Colour Tests. Chromotropic Acid—violet, after dilution Kop-panyi-Zwikker Test—violet Liebermann s Test—blue-green. 

Qualitative test for the presence of formaldehyde in fabrics Add a small piece of fabric to 2-3 ml of a solution of 10 mg chromotropic acid per 100 ml of 72 % sulfuric acid. Warm the solution carefnlly to not more than 100 °C for 1 min. A red to violet colour in the solntion indicates the presence of formaldehyde. 

The colour produced by reaction with formaldehyde and sulphuric acid or with chromotropic acid and sulphuric acid [82,83] has been used as an identity test to differentiate various penicillins and cephalosporins. Neither... 

Ventilation rate was 0.5 air changes per hour for all tests. Chromotropic acid was used... 

Pararosaniline was used for formaldehyde analysis, rather than chromotropic acid, using the same panel specimens as those used in the test whose results are reported directly above. 

Equilibrium Jar Method, Colorimetric Determination of Formaldehyde Using Chromotropic Acid Reagent for Product Testing - GPAM 203.6" Georgia Pacific Corporation, 1979. 

Ampicillin was identified by infrared spectroscopy. Chromotropic acid, sulfuric acid, ninhydrin and potassium cupri-tartrate tests are used to identify ampicillin. Electrophoresis in an agar gel is used for separation of penicillins. Spots are detected microbiologically. Thomas and Broadbridge described a method for the rapid separation and detection of mixtures of penicillins by low voltage electrophoresis. The penicillins are... 

British Pharmacopoeia identification test for primidone is the appearance of a pinkish-blue color on heating with chromotropic acid solution (53) ... 

The aqueous extracts or acid distillates are treated with chromotropic acid (1,8-dihydrox-ynaphthalene-3, 6-disulfonic acid). A few drops of 5% aqueous chromotropic add solution are added to the aqueous test solution and then an excess of concentrated sulfuric acid is added, and the mixture preferably warmed to nearly 100°C for a few minutes. In the presence of formaldehyde, the solution turns violet/dark violet. 

If the result is negative, test for bound formaldehyde. Heat a small sample of the plastic with 2 ml concentrated sulfuric acid and a few crystals of chromotropic acid for 10 min at 60-70°C. A deep violet coloration indicates formaldehyde. Cellulose nitrate, polyvinyl acetate, polyvinylbutyral, and cellulose acetate give a red coloration these materials, however, are not included in this part of the analytical procedure. 

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