Sodium nitroprusside test

DSniges mercuric sulfate test, described in Refs 2 19 b)Dinitrophenylhydrazine test, described in Refs 10 19 and C/The Faugbt sodium nitroprusside test, described in Ref 16, p 685 (see also Ref 12)... 

SrS04. White. Sulphate present. Confirm by fusion with Na2C03 and apply sodium nitroprusside test. Contains sulphurous acid. Add a few drops of a dilute solution of iodine the latter is decolourized.t Sulphite present. ... 

Sulphide, (i) Dilute H2S04 on solid, and action of H2S on lead or cadmium acetate paper (IV.6, 1). (ii) Sodium nitroprusside test (IV.6, 6). 

Two common qualitative tests for amines are the Hinsberg test and the nitrous acid test. The nitrous acid test is not included here because the N-nitroso derivatives of some secondary amines are carcinogenic. The risk of producing an as-yet-unrecognized carcinogenic material in this procedure outweighs any possible benefit of a test that can also be misleading and difficult to interpret. The modified sodium nitroprusside test has been included as an alternative. 

Sodium nitroprusside test Spot plate Spot test... 

Sodium nitroprusside test A presumptive test using the nitroprusside complex and the NO associated with the central iron cation. 

Sodium Nitroprusside Test for Acetoacetic Acid and Acetone (Rothera).—Fill up about 1 in. of a test tube with solid ammonium sulphate. Add 5 ml. of urine, and shake so as to saturate the mixture. Add 2-4 drops of fresh 5 per cent, sodium nitroprusside, and make alkaline with about 10 drops of strong ammonium hydroxide. A deep violet colour develops in a few seconds if the urine contains more than 0-2 per cent, acetoacetic acid, while 0 005 per cent, will give a pink colour in about ten minutes. 

Note cautiously the characteristic odour of acetaldehyde which this solution possesses. Then with the solution carry out the following general tests for aldehydes described on p. 341 Test No. I (SchiflF s reagent). No. 3 (Action of sodium hydroxide). No. 4 (Reduction of ammoniacal silver nitrate). Finally perform the two special tests for acetaldehyde given on p. 344 (Nitroprusside test and the Iodoform reaction). 

Sulphur. THE LASSAIGNE SODIUM TEST. The sodium fusion will have converted any sulphur present in the original compounds to sodium sulphide. Dissolve a few crystals of sodium nitroprusside, Na8[Fe(CN)5NO],zH20, in water, and add the solution to the third portion of the filtrate obtained from the sodium fusion. A brilliant purple coloration (resembling permanganate) indicates sulphur the coloration slowly fades on standing. Note, (i) Sodium nitroprusside is unstable in aqueous solution and therefore the solution should be freshly prepared on each occasion, (ii) This is a very delicate test for sulphides, and it is essential therefore that all apparatus, particularly test-tubes, should be quite clean. 

Sulphuric add test. Heat 0 5 g. of citric acid or a citrate with 1 ml. of H2SO4 CO and COg are evolved and the mixture turns yellow, but does not char. Acetone dicarboxylic acid, OC(CH2COOH)g, is also formed, and is tested for after heating the mixture for 1 minute cool, add a few ml. of water and make alkaline with NaOH solution. Add a few ml. of a freshly prepared solution of sodium nitroprusside and note the intense red coloration (see Test 4 a) for ketones, p. 346). 

Now add a few drops of a freshly prepared solution of sodium nitroprusside. A purple coloration is obtained (test for - SH Group),... 

Sulphur.—The presence of sulphur in organic compounds may be detected by heating the substance with a little metallic sodium or potassium. The alkaline sulphide, when dissolved in water, gives a violet colouration with a solution of sodium nitro-prusside. Heat a fragment of gelatine with a small piece of potassium in a test-tube until the bottom of the tube is red hot, and place it m a small beaker of water as described in the test for nitrogen (p. 2). Filter the liquid and add a few drops of sodium nitroprusside solution. 

Testing for Sulphur.—The qualitative test for sulphur is carried out in the same way as that for nitrogen. Ignite the substance in a small tube with sodium, dissolve the product in water, and add to one half of the cooled solution a few drops of sodium nitroprusside solution freshly prepared by shaking a few particles of the solid salt with cold water. A violet colour indicates the presence of sulphur. Since the nitroprusside reaction is extremely sensitive and does not allow any estimate of the amount of sulphur to be made, filter the second half of the liquid, add lead acetate solution to the filtrate, and acidify with acetic acid. According as the amount of sulphur is small or large, a dark turbidity or a more or less heavy precipitate will form. 

The cyanide nitroprusside test determines the presence of free sulfhydryl or disulfide compounds in urine samples [1, 3,4]. During the first step of the assay, cyanide reduces any disulfides that are present to free sulfhydryl compounds. In the second step, a reddish color reaction results when the free sulfhydryl groups complex with nitroprusside. A positive result is most usually due to cystine in the urine. Familial cystinuria is among the most common aminoacidurias. Disulfides are also excreted in other metabolic disorders such as homo cystinuria and ji-m e reap lol ac la le - cy s lei ne disulfiduria. Both will also produce positive results according to the following reaction RSH + Na2Fe(CN)5NO (sodium nitroprusside) — chromophore + NO. 

Detection.—Sulphur in the free state is readily recognisable by its general appearance and characteristics, and especially by its combustion to sulphur dioxide. Both in mixtures and compounds the presence of the element can be demonstrated by heating with charcoal and an alkali carbonate,2 or even better, on a small scale, by heating with an equal bulk of sodium or potassium,3 or with powdered iron 4 in each case some of the sulphur is converted into sulphide, which may be detected by the action of an aqueous extract on mercury or silver, or on sodium nitroprusside the metals are blackened, whilst the nitro-prusside is very sensitive in giving a purple coloration (see p. 62). Alternatively, the solution of the alkali sulphide may be acidified and tests applied for hydrogen sulphide to the vapours evolved on warming. 

Solutions of the alkali sulphides give a deep violet to purple coloration with a solution of sodium nitroprusside, and as mentioned on p. t. J, this may be used as a test for sulphides. By the interaction of the nitroprusside with the sulphides of lithium, sodium, potassium and rubidium, stable crystalline compounds of the type M4[Fc(CN)BNOS] have been obtained. From eleetrotitrimetric evidence the reaction appears to proceed in two stages 7... 

Structure-activity relationship. The endothelium-independent vasodilator effects showed by flavonoids are related to the structure of the compound tested. Structure- activity relationships have been studied to flavonoids selected from five groups flavonols, flavones, flavanones, isoflavones, and flavanols in rat isolated aorta on the contractions induced by noradrenaline, KC1 and the phorbol ester derivative PMA, as well as the interactions of these flavonoids with isoprenaline and sodium nitroprusside, Table (2). 

Free Sulphur.—This is detected by extracting with carbon disulphide and evaporating the solvent, or by treating the substance with alkali and testing the solution with sodium nitroprusside. 

Furthermore, the permeation-enhancing effects of NO donors seem to be strongly dose-dependent. Utoguchi et al. (1998) reported that the absorptionenhancing effect of S-nitroso-A-acetyl-penicillamine for rectal insulin absorption was dose-dependent over the range of 0.25-4.0 mg in rats. Similarly, Salzman et al. (1995) demonstrated that incubation with sodium nitroprusside resulted in a concentration-dependent increase in the transepithelial transport of fluorescein sulphonic acid in Caco-2 cells. To our knowledge the potential of NO donors for oral macromolecular delivery, however, has so far not been tested in a valid animal model. 

Sodium nitroprusside-zinc sulphate test Sodium nitroprusside solution reacts with a solution of a zinc salt to yield a salmon-coloured precipitate of zinc nitroprusside Zn[Fe(CN)5NO], The latter reacts with moist sulphur dioxide to give a red compound of unknown composition the test is rendered more sensitive when the reaction product is held over ammonia vapour which decolourizes the unused zinc nitroprusside. 

The spot-test technique is as follows. Mix on a spot plate a drop of the alkaline test solution with a drop of a 1 per cent solution of sodium nitroprusside. A violet colour appears. Alternatively, filter paper impregnated with an ammonia-cal (2m) solution of sodium nitroprusside may be employed. 

The test is usually carried out by adding the reagent to the solution acidified with dilute hydrochloric acid carbonates, sulphites, and phosphates are not precipitated under these conditions. Concentrated hydrochloric acid or concentrated nitric acid should not be used, as a precipitate of barium chloride or of barium nitrate may form these dissolve, however, upon dilution with water. The barium sulphate precipitate may be filtered from the hot solution and fused on charcoal with sodium carbonate, when sodium sulphide will be formed. The latter may be extracted with water, and the extract filtered into a freshly prepared solution of sodium nitroprusside, when a transient, purple colouration is obtained (see under Sulphides, Section IV.6, reaction 5). An alternative method is to add a few drops of very dilute hydrochloric acid to the fused mass, and to cover the latter with lead acetate paper a black stain of lead sulphide is produced on the paper. The so-called Hepar reaction, which is less sensitive than the above two tests, consists of placing the fusion product on a silver coin and moistening with a little water a brownish-black stain of silver sulphide results. 

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