Sodium nitroprusside, reagent for

Sodium nitroprusside (reagent for hydrogen sulfide and wool). 

Conventionai Tests. Prepare the sodium nitroprusside reagent for use in both the oonventional Ramini and Simon tests by dissolving 0.4 g of sodium nitroprusside (Na2[Fe(NO)(CN)5] 2 H2O in 10 mL of 50% aqueous methanol. 

Sodium nitroprusside (reagent for hydrogen sulfide and wool). Use a freshly prepared solution of 1 g of sodium nitroferricya-nide in 10 mL of distilled water. 

The main evidence for the thiazoline structure is the negative test for —SH groups given with the sodium nitroprusside reagent. 

For the nitroprusside-cyanide reagent two solutions are prepared. For solution I, sodium nitroferricyanide (sodium nitroprusside, 1.5 g) is dissolved in 2M H2S04 (5mL) to which MeOH (95 mL) and NH4OH (10 mL) is added. A precipitate forms that is discarded. The clear, red solution is refrigerated. For solution II, sodium cyanide (2g) is dissolved in H20 (5 mL) and diluted with MeOH (95 mL), this is filtered if necessary. CAUTION Sodium cyanide can be absorbed through the skin and is extremely toxic. Appropriate safety precautions and first aid procedures should be adopted when handling sodium cyanide. 

Several calorimetric methods were reported for spironolactone using different derivatization reagents, such as thiosemicarbazide at 440 nm [24], 4-dinitrobenzene at 400 nm [25], isoniazide at 375 nm [26], acetic acid-acetic anhydride then H2SO4 at 500 nm [27], 2,3,5-triphenyl-tetrazolium chloride and tetramethylammonium hydroxide at 480 nm [28] sodium nitroprusside at 700 nm, and phosphotungestic acid at 410 nm [29]. 

Successful attempts have been made to replace titration by direct colorimetric determination of ammonia. Berthelot s reaction has been carried out on the neutralized Kjeldahl digest (E6, L19), but interference by H2O2 and by Ca++ can occur (R13). The Berthelot reaction has been speeded up by the introduction of a catalyst, sodium nitroprusside (L19) it must be carried out at pH 10-12 (C5) under which conditions it is specific for NH4+ (W12). The reaction between NH4+ and indanetrione hydrate may also be used the digest is neutralized, buffered at pH 5.0, heated with the reagent at 110°C for 30 minutes, diluted with 50% ethanol, and the color measured at 570 nm (Jl). 

A color reaction based on the inoiganic reagent disodium pentacyano nitrosylferrate Na2[FE(CN)5(NO)], commonly called sodium nitroprusside, is used in the test. This reagent has been widely used for two different reactions that have formed the basis of photometric determinations of a large variety of compoxmds. 

Screening for amphetamines A highly sensitive screening strip for methyl amphetamine in urine may be prepared using the Simon reagent. A silica gel TLC plate is sprayed with equal volumes of 2% sodium nitroprusside and 5% aqueous sodium carbonate solution, and dried for 3 h at 110°C. A strip is cut from the plate to use in the test. 

The reagent which has been used most widely for the presumptive identification of —SH groups is sodium nitroprusside. It has also been applied as an end point indicator in titrations of —SH groups with p-chloromercuri-bensoate. Several procedures have been devised for its use in the quantitative determination of —SH groups two of these are described below. 

It is used as a reagent in qualitative analysis for the detection of sulphides, sulphites, aldehydes and ketones containing the CH3—CO—R group. It is also used as a reference compound for the cahbration of a Mossbauer spectrometer. Sodium nitroprusside is used to detect iUicit substances, such as secondary amines, in forensic laboratories (Simon s test). It is used to control blood pressure and to treat hypertension. 

Reagent Sodium nitroprusside is dissolved in a treble amount of cone, ammonia and allowed to stand at 0 °C for 24 hr. Alcohol is then added and the separated crystals are filtered off and washed with ethanol. To carry out the color reaction, a 1% aqueous solution of the product is prepared. 

Sodium Nitroprusside (Nitroferrocyanide), 5 per cent. Reagent for sulphydryl compounds, including cysteine, thioneine, and glutathione. Also reacts with acetone, acetoacetic acid, creatinine and indole. 

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). 

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