Amyl Nitrite
C5H11NO2 117.15

Mixture of nitrous acid,2-methylbutyl ester,and nitrous acid,3-methylbutyl ester [8017-89-8;110-46-3].
»Amyl Nitrite is a mixture of the nitrite esters of 3-methyl-1-butanol and 2-methyl-1-butanol.It contains not less than 85.0percent and not more than 103.0percent of C5H11NO2.
Caution—Amyl Nitrite is very flammable.Do not use where it may be ignited.
Packaging and storage— Preserve in tight containers,and store in a cool place,protected from light.
Identification—
A: The NMRspectrum recorded as directed in the Assayexhibits,among other peaks,a doublet with a band centered at about 1ppm and a multiplet with a band centered at about 4.8ppm representing methyl protons and methylene protons alpha to the nitrite group,respectively,both relative to the tetramethylsilane singlet at 0ppm.
B: To a few drops of it add a mixture of 1mLof ferrous sulfate TSand 5mLof 3Nhydrochloric acid:a greenish brown color is produced.
Specific gravity á841ñ: between 0.870and 0.876.
Acidity— To 0.30mLin a glass-stoppered cylinder add a mixture of 0.60mLof 0.1Nsodium hydroxide,10mLof water,and 1drop of phenolphthalein TS,and invert the cylinder three times:the red tint of the water layer is still perceptible.
Limit of nonvolatile residue— Allow 10mLto evaporate at room temperature in a tared evaporating dish,in a well-ventilated hood,and dry the residue at 105for 1hour:the weight of the residue does not exceed 2mg (0.02%).
Content of total nitrites— Inject a portion of Amyl Nitrite of suitable volume,but not more than 2µL,into a suitable gas chromatograph (see Chromatography á621ñ)equipped with a thermal conductivity detector.Under typical conditions,the instrument contains a 3-mm ×2-m column packed with a methyl polysiloxane oil,25%by weight on suitable calcined diatomite,the column is maintained at about 80,the injection port and detector block are maintained about 10above the temperature of the column,and helium is used as a carrier gas at a flow rate of about 60mLper minute.From the area under the curve,calculate the percentage (a/a)of total nitrites,represented by the area under the main peak of the chromatogram,in the Amyl Nitrite taken:not less than 97.0%is found.
Organic volatile impurities,Method Vá467ñ: meets the requirements.
Solvent— Use dimethyl sulfoxide.
Assay—
Solvent: carbon tetrachloride.
Internal standard— USP Benzyl Benzoate RS.
Procedure— Transfer 4to 5mEq of Internal standard,accurately weighed,to a semimicro sampling tube,add 2to 3mLof carbon tetrachloride,apply a sampling valve and septum,*thereby sealing the tube,and determine the weight of the sealed assembly.Open the valve,introduce about 500µLof Amyl Nitrite with a syringe,close the valve,and determine the weight of the sealed assembly when it has attained constant weight.Shake the sampling tube and valve assembly,and transfer about 500µLof the solution to a precision NMRtube as directed for Absolute Method of Quantitationunder Nuclear Magnetic Resonance á761ñ.With no spinning,or with the spinning adjusted so that the spinning side bands of neither the substance under assay nor the Internal standardinterfere with the regions to be integrated,record as ASthe average area of the Internal standardsinglet appearing at about 5.3ppm,representing the methylene protons of benzyl benzoate,and record as AUthe average area of the multiplet with a band center at about 4.8ppm,representing the alpha methylene protons of amyl nitrite,with reference to the tetramethylsilane singlet at 0ppm.Calculate the quantity of C5H11NO2in the Amyl Nitrite taken,using 58.57as the equivalent weight of amyl nitrite (EWU)and 106.12as that of benzyl benzoate (EWS).
*  Suitable sampling tubes,sampling valves,and septums are available,respectively,as catalog Nos.K-749000,K-749100,and K-749102(50septums)or K-749101(100septums),from Kontes Glass Company,Vineland,NJ08360.
Auxiliary Information— Staff Liaison:Andrzej Wilk,Ph.D.,Senior Scientific Associate
Expert Committee:(PA5)Pharmaceutical Analysis 5
USP28–NF23Page 158
Phone Number:1-301-816-8305