title: Improved GC/MS analysis of opiates with use of oxime-TMS derivatives.
abstract: An improved gas chromatographic/mass spectrometric (GC/MS) assay is described for the quantitation of codeine and morphine as trimethylsyl (TMS) derivatives. The TMS derivatization of ketone-containing opiates results in the formation of multiple derivatives. Some of these products have retention times close to those of codeine-TMS and morphine-TMS. When the keto-opiates are present in samples assayed for codeine and morphine in urine, they can interfere with the quantitation of these commonly targeted opiates. The assay was improved with the addition of a pre-BSTFA derivatization step, whereby hydroxylamine was used to convert the keto-opiates into the corresponding oxime derivative. These derivatives were then reacted with BSTFA to form the TMS ethers and TMS oxime derivatives. The oxime step enabled production of single derivatives for hydrocodone and hydromorphone. In addition, the retention times for the oxime-TMS derivatives were increased so that they no longer elute near the targeted drugs of codeine and morphine. The addition of the oxime step does not affect the sylation of codeine and morphine, and the accuracy and precision of this assay were unaffected.
authors.affiliation: Department of Pathology and Laboratory Medicine, Hartford Hospital, CT 06102, USA.
authors.forename: M
authors.initials: M
authors.lastname: Cremese
authors.forename: A H
authors.initials: AH
authors.lastname: Wu
authors.forename: G
authors.initials: G
authors.lastname: Cassella
authors.forename: E
authors.initials: E
authors.lastname: O'Connor
authors.forename: K
authors.initials: K
authors.lastname: Rymut
authors.forename: D W
authors.initials: DW
authors.lastname: Hill
mesh_terms: D003061:Codeine / Q000652:urine*; D017248:Enzyme Multiplied Immunoassay Technique; D005554:Forensic Medicine / Q000379:methods; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006801:Humans; D019811:Hydroxylamine / Q000737:chemistry; D007202:Indicators and Reagents / Q000737:chemistry*; D009020:Morphine / Q000652:urine*; D010091:Oximes / Q000737:chemistry*; D015813:Substance Abuse Detection / Q000379:methods*; D014297:Trimethylsilyl Compounds / Q000737:chemistry
chemical_list: D007202:Indicators and Reagents; D010091:Oximes; D014297:Trimethylsilyl Compounds; D019811:Hydroxylamine; C047270:N,N-bis(trimethylsilyl)-2,2,2-trifluoroacetamide; C039293:trimethylchlorosilane; D009020:Morphine; D003061:Codeine