A Simple and Reliable Method to Determine 16 Trace Elements by ICP OES in Ready to Drink Beverages

Abstract

In this work, multivariate experiments were carried out to optimize a simple and reliable method for determination of 16 trace elements (Al, As, Cd, Co, Cr, Cu, Fe, Li, Mn, Ni, Pb, Sb, Se, Sr, Sn, and Zn) in ready to drink beverages by ICP OES. The multivariate methodology to optimize ICP OES parameters consisted in a 24-1 and a 23 central composite design, where the variables studied were radio frequency power, nebulization flow rate, auxiliary argon flow rate, and argon plasma flow rate and the responses were signal to background ratio (SBR) and the plasma robustness. The compromised conditions were RF power, 1.35 kW; nebulization flow rate, 0.50 L min−1 ; auxiliary argon flow rate, 0.55 L min−1 ; and argon plasma flow rate, 12.0 L min−1 . Under these conditions, the microwave digestion using diluted oxidant mixture provided recoveries between 79 and 110% for quantifiable trace elements in two reference materials (corn brand and tea leaves) and 81 and 118% in spiked experiments. The method was successfully applied to 10 samples of ready to drink beverages (fruit juice, soy-based beverages, and tea), and the levels found were below the maximum allowed for inorganic contaminants by Brazilian, European, and MERCOSUL regulations.