Figure 1: Chromatogram of a spiked urine specimen. Peak identity and concentration (ng/mL) are listed below. 1: morphine (250); 2: oxymorphone (250); 3: hydromorphone (250); 4: dihydrocodeine (250); 5: codeine (250); 6: amphetamine (250); 7: O-desmethyltramadol (250); 8: benzoylecgonine (250); 9: Oxycodone (250); 10: 6-MAM (250); 11: methamphetamine (250); 12: hydrocodone (250); 13: norfentanyl (250); 14: tramadol (250); 15: norbuprenorphine (250); 16: THCA (1000); 17: buprenorphine (1000); 18: fentanyl (25); 19: methadone (25); 20: EDDP (25). The three newly added analytes are highlighted with underscores.