181 IDENTIFICATIONORGANIC NITROGENOUS BASES
This test is for the identification of tertiary amine compounds.
Dissolve 50 mg of the substance under test, if in bulk, in 25 mL of 0.01 N hydrochloric acid, or shake a quantity of powdered tablets or the contents of capsules equivalent to 50 mg of the substance with 25 mL of 0.01 N hydrochloric acid for 10 minutes. Transfer the liquid to a separator, if necessary filtering it and washing the filter and the residue with several small portions of water. In a second separator dissolve 50 mg of the corresponding USP Reference Standard in 25 mL of 0.01 N hydrochloric acid. Treat each solution as follows. Add 2 mL of 1 N sodium hydroxide and 4 mL of carbon disulfide, and shake for 2 minutes. Centrifuge if necessary to clarify the lower phase, and filter it through a dry filter, collecting the filtrate in a small flask provided with a glass stopper.
Determine the absorption spectra of the filtered solutions of both standard and sample without delay, in 1-mm cells between 7 µm and 15 µm, with a suitable IR spectrophotometer, using carbon disulfide in a matched cell as the blank. The spectrum of the solution prepared from the sample shows all of the significant absorption bands present in the spectrum of the solution prepared from the Reference Standard.