Solvent: carbon tetrachloride.

Internal standard— USP Benzyl Benzoate RS.

Procedure— Remove the gauze or other covering from 1 or more Inhalant ampuls containing a total of 300 to 400 µL of amyl nitrite. Weigh accurately the clean and dry intact glass ampul(s), and place the weighed specimen in a freezer for not less than 15 minutes. Transfer the chilled specimen to a glass-stoppered, 25-mL conical flask containing a solution of 4 to 5 mEq of Internal standard, accurately weighed, in 1 to 2 mL of carbon tetrachloride. Break the ampul(s) with a glass rod, and rinse any sample or glass fragments adhering to the glass rod with 1 mL of carbon tetrachloride into the main assay solution. Insert the stopper in the flask immediately, mix, and proceed as directed for Absolute Method of Quantitation under Nuclear Magnetic Resonance 761, beginning with “When dissolution has been completed.” With no spinning, or with the spinning adjusted so that the spinning side bands of neither the substance under assay nor the Internal standard interfere with the regions to be integrated, record as AS the average area of the Internal standard singlet appearing at about 5.3 ppm, representing the methylene protons of benzyl benzoate, and record as AU the average area of the multiplet with a band center at about 4.8 ppm, representing the alpha methylene protons of amyl nitrite, with reference to the tetramethylsilane singlet at 0 ppm. Calculate the quantity of C5H11NO2 in the Inhalant taken, using 58.57 as the equivalent weight of amyl nitrite (EWU) and 106.12 as that of benzyl benzoate (EWS). Rinse the flask containing the assay preparation with three 5-mL portions of ether, decanting each rinsing carefully to avoid loss of glass fragments, and evaporate any remaining ether with the aid of a current of dry air. Transfer the dry glass fragments to a tared watch glass, weigh, and subtract the weight of the glass fragments from that of the intact ampul(s) to obtain the weight of the Inhalant taken.