title: Method development and validation for the GC-FID assay of p-cymene in tea tree oil formulation.
abstract: This paper describes the development and validation of an isothermal gas chromatography-flame ionisation detection (GC-FID) method for the assay of pure tea tree oil. The chromatographic conditions of the method employ a 5% carbowax packed column (20 m x 0.25 mm), isothermal elution with hydrogen at a column flow of 36 ml/min, injector and detector temperature at 220 degrees C and oven temperature at 100 degrees C, and a 1.5 microl injection volume. Samples and standard were diluted in hexane. The calibration curve for p-cymene was linear (r2=0.9995) from 20 to 120% range of the analytical concentration of 100 microg/ml. The precision of this method was calculated as the relative standard deviation (R.S.D.) was 0.66% (n=6). The R.S.D. for intermediate precision study was 0.13 and recovery of the p-cymene ranged between 93.39 and 97.86%. The limits of detection and quantitation were determined to be 2.08 and 10.39 ng/ml, respectively.
authors.affiliation: Fleet Laboratories, Watford, Hertfordshire WD18 7JJ, UK.
authors.forename: Ghulam A
authors.initials: GA
authors.lastname: Shabir
mesh_terms: D002138:Calibration; D002626:Chemistry, Pharmaceutical / Q000379:methods*; D002845:Chromatography; D002849:Chromatography, Gas / Q000379:methods*; D000081007:Cymenes; D005410:Flame Ionization; D006586:Hexanes / Q000737:chemistry; D006838:Hydrocarbons / Q000032:analysis; D006859:Hydrogen / Q000032:analysis; D008956:Models, Chemical; D039821:Monoterpenes / Q000032:analysis*; D011786:Quality Control; D015203:Reproducibility of Results; D020947:Tea Tree Oil / Q000032:analysis*; D013678:Technology, Pharmaceutical / Q000295:instrumentation / Q000379:methods*; D013696:Temperature; D013997:Time Factors
chemical_list: D000081007:Cymenes; D006586:Hexanes; D006838:Hydrocarbons; D039821:Monoterpenes; C007210:4-cymene; D020947:Tea Tree Oil; D006859:Hydrogen