PCAA, or 5-[N-(1-phenylcyclohexyl)amino]pentanoic acid, is a metabolite of phencyclidine (PCP). It can be detected in the urine of PCP users by mass spectrometry as means of drug screening.[1]
^Ojanpera, Suvi; Pelander, Anna; Pelzing, Matthias; Krebs, Ilmari; Vuori, Erkki; Ojanpera, Ilkka (2006). "Isotopic pattern and accurate mass determination in urine drug screening by liquid chromatography/time-of-flight mass spectrometry". Rapid Communications in Mass Spectrometry. 20 (7): 1161–1167. Bibcode:2006RCMS...20.1161O. doi:10.1002/rcm.2429. PMID16521169.