A Simple and Rapid Gas Chromatographic Method for Routine Caffeine Determination in Beverages using Nitrogen Phosphorus Detector

Abstract

Caffeine is a common ingredient in beverages important to be monitored, as there are regulations worldwide. In this study, an analytical method was developed for routine caffeine determination in beverages. The sample pretreatment only takes a few minutes. Caffeine in the sample is extracted by 1 mL of ethyl acetate under sonication. The ethyl acetate phase is then dried by 0.08 g of anhydrous sodium sulfate and directly injected to gas chromatography–nitrogen phosphorus detector. The method was optimized to achieve high rate of recovery of 90.9–111.7% with RSD of <5% for fourteen real beverage samples. The method detection limit was 3.5 mg/L. Apart from the advantages of simplicity and rapidity, the method is relatively green, accurate, precise, sensitive, has a high throughput, low cost of operation and maintenance and can be recommended for the quantification of caffeine in various common beverages.