Development of a method for the sequential determination of cadmium and chromium from the same sample aliquot of yerba mate using high-resolution continuum source graphite furnace atomic absorption spectrometry

• A method for sequential determination of Cd and Cr in yerba mate and leaves of yerba mate by HR-CS GF AAS was developed.
• The determination could be performed without chemical modifier.
• Direct solid sampling and liquid analysis were employed.
• Accuracy of the method was confirmed using CRM.

A simple, fast and sensitive method for the sequential determination of cadmium and chromium from the same sample aliquot of yerba mate and leaves of yerba mate is proposed using high-resolution continuum source graphite furnace atomic absorption spectrometry and direct solid sample analysis. The measures were made using the analytical line at 228.802 nm for cadmium and 357.869 nm for chromium, and three pixels each for evaluation. The reference material NCS ZC73014 (trace elements in tea) has been analyzed and the results were in agreement with the certified values. A characteristic mass of 0.37 pg and 2.4 pg was obtained for cadmium and chromium, respectively. The limits of detection were 0.25 ng for cadmium and 0.72 ng for chromium, and the precision, expressed as relative standard deviation, was around 10%. Thirteen commercial samples and five leave samples were analyzed and the concentration of cadmium varied between 0.28 and 2.06 μg g− 1 and that of chromium between 0.27 and 2.37 μg g− 1. The process of infusion preparation resulted in a leaching of around 25% for cadmium and 60% for chromium.