Simultaneous Determination of Theobromine, Paraxanthine, Theophylline, and Caffeine in Urine by Reversed-Phase High-Performance Liquid Chromatography with Diode Array UV Detection

Buyuktuncel E.

ANALYTICAL LETTERS, vol.43, no.16, pp.2518-2524, 2010 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 43 Issue: 16
  • Publication Date: 2010
  • Doi Number: 10.1080/00032711003731357
  • Journal Name: ANALYTICAL LETTERS
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.2518-2524
  • Inonu University Affiliated: Yes

Abstract

A reversed-phase high performance liquid chromatographic method was improved for the simultaneous determination of theobromine, paraxanthine, theophylline, and caffeine in urine. The method includes a liquid-liquid extraction at alkaline pH with ethylacetate. The 7-(2,3-dihidroxypropyl) theophylline was used as an internal standard (ISTD). The separation was achieved on a C18 column using 14:86 methanol:buffer (25mM KH2PO4 adjusted to pH 4 with ortho-phosphoric acid) solution as mobile phase under isocratic conditions at a flow rate 1mLmin-1. An ultraviolet absorption at 274nm was monitored. In these conditions, the LOD was 0.03gmL-1 for theobromine, 0.02gmL-1 for paraxanthine, 0.04gmL-1 for theophylline, and 0.08gmL-1 for caffeine. The method has been applied to urine samples.