DOI: https://doi.org/10.55373/mjchem.v25i1.1

Keywords: First-order derivative; caffeine; chlorogenic acid; coffee; roasting degrees

Abstract

Due to an overlap in the their absorption spectra, the direct simultaneous analysis of caffeine (CFI) and chlorogenic acid (CGA) by UV-Vis is impossible. This study aims to propose an analytical method that employs the principle of first-order derivative spectra for the simultaneous determination of CFI and CGA in coffee. The extraction was conducted at 90 °C in 50 minutes using deionized water as a "green" extraction solvent. The performance of the proposed method was evaluated and the results were not significantly different to those obtained with the HPLC-DAD reference method, i.e., texperimental < tcritical (2.23, P = 95%). The working ranges were from 0.50 to 16.5 mg L–1 and 2.00 to 28.5 mg L–1 for CFI and CGA, respectively, with favourable repeatability (RSDr of 1.88% and 0.77%) and reproducibility (RSDR of 2.34% and 1.43%) values. The proposed method was applied to evaluate CFI and CGA concentrations in several ground coffee products of different varieties and roasting degrees, and was found to have the potential to replace the HPLC-DAD for regulating and controlling CFI and CGA as it is a quick, easy, and cheap method.