A new analytical method was proposed for multielement (Al, Ba, Ca, Cu, Fe, K, Mg, Mn, Na, Sr and Zn) analysis of Pu-erh teas infusions by inductively coupled plasma optical emission spectrometry. The Box-Behnken response surface design together with individual desirability functions and the joint desirability function approach was applied to develop experimental conditions of this new procedure, being alternative to high-temperature wet digestion. The procedure involved the samples to be just 5-fold diluted with 1.7 mol L-1 HNO3. The proposed method was precise (relative standard deviations within 2-8%), true (relative errors from -8 to +6%) and guaranteed very good detectability (detection limits within 1-6 ng g-1, except for Ca and Fe). It was used for analysis of infusions of Pu-erh teas as well as to verify the effect of their preparation conditions (steeping water temperature, steeping time).
Keywords: Decomposition-free sample preparation; Desirability function; ICP OES; Multielement analysis; Pu-erh tea infusion; Response surface design.
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