Determination of Multiple Elemental Concentrations in Tea from China by Inductively Coupled Plasma Optical Emission Spectrometry

The main goals of this study were to determine the best preparation procedure (microwave digestion, infrared digestion, or dry ashing) to analyze 17 elements in ten tea samples from different manufacturers in China with inductively coupled plasma optical emission spectrometry. Elemental measurement accuracy was determined by comparison with certified green tea reference material (GBW10052). Our results showed that a simple, rapid, and reliable microwave digestion was the best procedure preceding spectrometric measurements, resulting in the highest mean content values of K, Ca, Mg, Fe, and Zn in the tea samples, and that Cd, Pb, and As were under permissible limits based on a national standard (NY695-2003). The elemental differences and correlation of samples, as well as the classification and differentiation between the tea samples, were analyzed statistically.