The infrared internal reflection spectra of the hydrochloride salts of tetracycline, chlortetracycline, oxytetracycline, 6-deoxyoxytetracycline, and 6-methylene-oxytetracycline as well as tetracycline base and oxytetracycline base are reported from 1700 to 300 cm−1. This technique yielded sharp, well defined spectra with numerous strong absorption peaks.
