Detection of Δ9-tetrahydrocannabinolic acid A in human urine and blood serum by LC-MS/MS Jung, Julia ; Kempf, Juergen ; Mahler, Hellmut ; Weinmann, Wolfgang Abstract Publication: Journal of Mass Spectrometry Pub Date: March 2007 DOI: 10.1002/jms.1167 Bibcode: 2007JMSp...42..354J