title: Automated in-tube solid-phase microextraction-liquid chromatography-electrospray ionization mass spectrometry for the determination of ranitidine.
abstract: The technique of automated in-tube solid-phase microextraction (SPME) coupled with liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) was evaluated for the determination of ranitidine. In-tube SPME is an extraction technique for organic compounds in aqueous samples, in which analytes are extracted from the sample directly into an open tubular capillary column by repeated aspirate/dispense steps. In order to optimize the extraction of ranitidine, several in-tube SPME parameters such as capillary column stationary phase, extraction pH and number and volume of aspirate/dispense steps were investigated. The optimum extraction conditions for ranitidine from aqueous samples were 10 aspirate/dispense steps of 30 microliters of sample in 25 mM Tris-HCl (pH 8.5) with an Omegawax 250 capillary column (60 cm x 0.25 mm I.D., 0.25 micron film thickness). The ranitidine extracted on the capillary column was easily desorbed with methanol, and then transported to the Supelcosil LC-CN column with the mobile phase methanol-2-propanol-5 M ammonium acetate (50:50:1). The ranitidine eluted from the column was determined by ESI-MS in selected ion monitoring mode. In-tube SPME followed by LC-ESI-MS was performed automatically using the HP 1100 autosampler. Each analysis required 16 min, and carryover of ranitidine in this system was below 1%. The calibration curve of ranitidine in the range of 5-1000 ng/ml was linear with a correlation coefficient of 0.9997 (n = 24), and a detection limit at a signal-to-noise ratio of three was ca. 1.4 ng/ml. The within-day and between-day variations in ranitidine analysis were 2.5 and 6.2% (n = 5), respectively. This method was also applied for the analyses of tablet and urine samples.
authors.affiliation: Department of Chemistry, University of Waterloo, Ontario, Canada.
authors.forename: H
authors.initials: H
authors.lastname: Kataoka
authors.forename: H L
authors.initials: HL
authors.lastname: Lord
authors.forename: J
authors.initials: J
authors.lastname: Pawliszyn
mesh_terms: D000897:Anti-Ulcer Agents / Q000032:analysis* / Q000652:urine; D002853:Chromatography, Liquid / Q000379:methods*; D006635:Histamine H2 Antagonists / Q000032:analysis* / Q000652:urine; D013058:Mass Spectrometry / Q000379:methods*; D011899:Ranitidine / Q000032:analysis* / Q000652:urine; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D000897:Anti-Ulcer Agents; D006635:Histamine H2 Antagonists; D011899:Ranitidine