Minimalism approach for determination of Cu, Fe and Zn in serum by simultaneous electrothermal atomic absorption spectrometry

Copper, iron and zinc were determined in serum by simultaneous atomic absorption spectrometry (SIMAAS). The minimalism approach was adopted throughout this analytical method, to reduce time, costs, sample, reagent, energy requirements, and residue production. Samples were 80-fold diluted with 0.01% (w/v) Triton X-100+1% (v/v) HNO₃ directly in the autosampler cups. Three strategies were implemented to match the final diluted analyte concentrations with the SIMAAS linear concentration ranges: a reduced 5 μl aliquot of analytical reference or diluted sample solution was introduced into the preheated graphite tube at 100 °C; a super-estimated pyrolysis temperature was chosen for selective zinc volatilization; and a mini argon flow of 50 ml min⁻¹ was used during the atomization step. The pyrolysis and atomization temperatures for the simultaneous heating program were 700 and 2300 °C, respectively. The characteristic masses for copper (26 pg), iron (16 pg), and zinc (2.7 pg) were estimated from the analytical graphs. The detection limits (n=20, 3σ) were 4.0, 2.2, and 0.4 μg l⁻¹ for copper, iron and zinc, respectively. The reliability of the entire procedure was checked with the analysis of Seronorm™ trace elements in serum (Sero AS). Serum samples of five volunteers were analyzed and the recovery tests for additions of 2.0, 2.0 and 1.0 mg l⁻¹ were 100±4, 99±6, and 95±5% for copper, iron and zinc, respectively.