Large Phase Ratio Spontaneous Extraction Followed by GC-MS for the Determination of Caffeine in Beverages

A single-step large phase ratio spontaneous extraction procedure followed by gas chromatography-mass spectrometry (GC-MS) was successfully applied for the determination of caffeine in beverages. Before the GC-MS analysis, as little as 25 μL sample was spontaneously extracted with 1 mL chloroform in a 2 mL autosampler vial for 15 min. The methodology exhibited excellent linearity in the range of 0.001-20 mg L⁻¹ with correlation coefficient of determination, r ² > 0.9999 and a detection limit of 0.004 mg L⁻¹. Good repeatability of extraction performance was obtained with relative standard deviation lower than 2% and the recovery of the caffeine when spiked to three different brand beverages was in the range of 98.8-102.3%. The new application-oriented single-step spontaneous extraction method was fast, efficient, and is a good alternative to routine methods for caffeine analysis in beverages.