title: Identification of interference affecting the gas-liquid chromatography analysis of valproic acid in quality control material.
abstract: The matrix used to prepare control material for the Chemical Pathology Quality Assurance Programme Group of the Royal College of Pathologists of Australasia/Australian Association of Clinical Biochemists (RCPA/AACB) was investigated to identify a contaminant affecting the gas-liquid chromatography (GLC) analysis of valproic acid (VPA). The contaminant, not present in patients' sera, eluted with the octanoic acid internal standard in our GLC procedure. The compound was identified as octanoic acid. The source of this contamination could not be determined. The presence of endogenous octanoic acid in the RCPA/AACB quality control material precluded the use of octanoic acid as an internal standard.
mesh_terms: D002849:Chromatography, Gas / Q000592:standards*; D004340:Drug Contamination; D006801:Humans; D011786:Quality Control; D014635:Valproic Acid / Q000032:analysis*
chemical_list: D014635:Valproic Acid