title: Determination of morphine in biological samples by gas chromatography-mass spectrometry. Evidence for persistent tissue binding in rats twenty-two days post-withdrawal.
abstract: Combined gas chromatography-mass spectrometry with capillary and packed column gas chromatography and a deuterium-labelled internal standard was used to determine morphine in biological specimens from rats 22 days after abrupt withdrawal. Morphine was extracted from urine and body organs at pH 9 and the pentafluoropropionyl derivatives were made for analysis by gas chromatography-mass spectrometry. The stationary phase was OV-17 and the mass spectrometer was focused on m/z 414 for morphine and m/z 417 for the internal standard, [NC2H3]morphine. With fused-silica capillary columns, the sensitivity of the assay was increased about ten-fold over packed columns. Urinary excretion of total morphine (free + conjugated) was 22 ng/h (range 11-51 ng/h, n = 8) at 22 days post-withdrawal. Free morphine was mainly detected in the lung (1.8-6.5 ng/g, n = 7), kidney (1.5-4.0 ng/g, n = 7) and liver (1.8-4.6 ng/g, n = 4). Traces of morphine were also detected in brain of some rats. Treatment with the opiate antagonist naltrexone, 10 mg/kg on four consecutive days before death, failed to change the urinary excretion pattern or the concentration of free morphine in body organs. The biological significance of the residual morphine, if any, remains to be determined.
mesh_terms: D000818:Animals; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006801:Humans; D007668:Kidney / Q000032:analysis; D008168:Lung / Q000032:analysis; D008297:Male; D009020:Morphine / Q000032:analysis* / Q000378:metabolism / Q000652:urine; D051381:Rats; D011919:Rats, Inbred Strains; D013375:Substance Withdrawal Syndrome / Q000378:metabolism*; D013997:Time Factors
chemical_list: D009020:Morphine