Determination of Cadmium, Chromium, Copper, Iron, Lead, Magnesium, Manganese, Potassium, and Zinc in Mint Tea Leaves by Electrothermal Atomizer Atomic Absorption Spectrometry in Samples Purchased at Local Supermarkets and Marketplaces

Abstract

The concentrations of Cd, Cr, Cu, Fe, K, Mg, Mn, Pb, and Zn in 14 different samples of mint leaves (Mentha piperitae folium) and tea bags purchased in local supermarkets and marketplaces in Split, Croatia were determined. Electrothermal atomic absorption spectrometry (ETAAS) was applied in this work. Mint tea samples purchased at marketplaces contained: Cd (0.021–0.357 mg kg⁻¹), Cr (<0.01–52.3 mg kg⁻¹), Cu (3.23–5.56 mg kg⁻¹), Fe (47.7–208 mg kg⁻¹), K (7.47–21.7 g kg⁻¹), Mg (2.16–15.9 g kg⁻¹), Mn (24.2–667 mg kg⁻¹), Pb (1.31–1.49 mg kg⁻¹), and Zn (2.33–19.5 mg kg⁻¹). Those ones purchased at supermarkets contained: Cd (0.19–0.34 mg kg⁻¹), Cr (7.3–99 mg kg⁻¹), Cu (1.70–5.21 mg kg⁻¹), Fe (0.16–1.42 g kg⁻¹), K (0.23–60.8 g kg⁻¹), Mg (0.13–16.3 mg kg⁻¹), Mn (0.30–0.93 mg kg⁻¹), Pb (<0.01–1.73 mg kg⁻¹), and Zn (<0.01–24.9 mg kg⁻¹). In order to get a better insight into the elemental patterns in mint leaves, a One-Way ANOVA program R was used for statistical data analysis. The One-way ANOVA was performed with the amount of each metal as the dependent variable and market as the independent variable. The PCA (principal component analysis) was applied to analyze the grouping of mint leaves on supermarket and marketplace samples.

Keywords:

• Chemometrics
• Determination
• ETAAS
• Peppermint tea
• Trace elements

Notes

Note: K_i, local supermarkets; V_i, marketplace.

^a Standard deviation.

^a Probability of Mann-Whitney test parameter indicating similar ranges was used to test the difference between two independent samples.

^b Different letters indicate statistical difference at level of 0.05.