Solid sampling ETV-ICPOES coupled to a nebulization/pre-evaporation system for direct elemental analysis of glutinous rice by external calibration with standard solutions

Abstract

Because glutinous rice flour is consumed by millions of individuals around the world, its analysis is essential to ensure its safety. Solid sampling electrothermal vaporization (ETV) coupled to inductively coupled plasma optical emission spectrometry (ICPOES) allows for a quick analysis, precluding the need for time-consuming acid digestion that may also lead to analyte loss or contamination. However, the amount of sample that can be introduced without extinguishing the plasma is limited to about 4mg. The increase in plasma robustness resulting from the concurrent introduction of pre-evaporated water aerosol allows the introduction of 8mg of solid sample without extinguishing the plasma. This modified set-up was compared to conventional ETV for the determination of several elements in three different brands of glutinous rice flour. Not only are detection limits improved, but dried aqueous standard solutions can be used for external calibration, thereby significantly increasing the applicability of solid sampling ETV-ICPOES.