Simultaneous determination of glyoxal, methylglyoxal and diacetyl in beverages using vortex-assisted liquid–liquid microextraction coupled with HPLC-DAD

Abstract

The detection of α-dicarbonyl compounds including glyoxal (GO), methylglyoxal (MGO) and diacetyl (DA) levels in beverages could be effectively used to evaluate the degree of sugar degradation. In this study, a rapid and inexpensive clean-up method called vortex-assisted liquid–liquid microextraction (VALLME) instead of the expensive solid phase extraction method was successfully applied to purify beverages (tea drinks, soft drinks and carbonated drinks) containing α-dicarbonyl compounds after derivatization with o-phenylenediamine. The clean-up samples were analyzed by using a high-performance liquid chromatography-diode array detector (HPLC-DAD). The matrix effects were corrected by using an internal standard (3,4-hexanedione). The limits of quantitation (LOQs) ranging from 22.3 μg L⁻¹ to 22.7 μg L⁻¹ for GO, from 6.4 μg L⁻¹ to 6.7 μg L⁻¹ for MGO and from 5.4 to 6.2 μg L⁻¹ for DA were observed for standards spiked into tea drinks, soft drinks or carbonated drinks. In addition, the developed method exhibited excellent linearity (R² > 0.99) for GO (recovery rates, 85.0–108.0%), MGO (recovery rates, 90.8–113.0%) and DA (recovery rates, 93.8–109.3%). The contents of GO (ranging from 265.8 to 9899.8 μg L⁻¹), MGO (<319.7 μg L⁻¹), and DA (<298.6 μg L⁻¹) were accurately quantified in fifteen beverage samples. VALLME as an inexpensive, rapid and valid technique improved the HPLC-DAD determination of GO, MGO and DA in drinks.