Response surface methodology assisted development of a simplified sample preparation procedure for the multielement (Ba, Ca, Cu, Fe, K, Mg, Mn, Na, Sr and Zn) analysis of different coffee brews by means of inductively coupled plasma optical emission spectrometry.

ABSTRACT

The Box-Behnken response surface design together with the individual desirability functions were used to develop the new and greenish sample preparation procedure of coffee brews prior to their multielement (Ba, Ca, Cu, Fe, K, Mg, Mn, Na, Sr and Zn) analysis by inductively coupled plasma optical emission spectrometry (ICP OES). The developed procedure required only 2-fold dilution of the samples with a 1.8 mol L-1 HNO3 solution and then, the sonication of the resulting samples solutions for 8 min at room temperature. The proposed method was precise (0.6-7.5% as RSD), true (relative errors changing from -5.2% to +4.6%) and guaranteed the limits of detection (LODs) of the studied elements between 0.1 and 5 ng g-1. Finally, this simplified ICP OES based method was applied for the multielement analysis of brews of different Arabica coffees as well as those prepared with seldomly reported devices, i.e., dripper, slow dripper, French press, aeropress and syphon.