Use of fast alkaline solubilisation to determine copper in bovine liver, fish tissues (salmon), and rolled oats by graphite furnace atomic absorption spectrometry using aqueous calibration

In this work, efficient methods to determine Cu in bovine liver, fish tissue, and rolled oats by graphite furnace atomic absorption spectrometry (GF AAS), after fast alkaline solubilisation of the samples with Universol® (a new reagent for sample solubilisation, benzyltrimethylammonium hydroxide in 40 % v/v of water), were presented. The optimum modifiers were permanent Ir (500 μg) plus co-injection of Ru (5 μg) for bovine liver, permanent Nb (500 μg) for salmon, and permanent Ir (500 μg) with co-injection of Pt (5 μg) for rolled oats. The optimum pyrolysis (PT) and atomization temperatures (AT) (obtained by pyrolysis and atomization curves) were of PT of 1300 °C for all matrices, and AT of 1800 °C for bovine liver and 2300 °C for salmon and rolled oats. Aqueous and matrix matching calibration curves (n = 3 curves for each calibration), had average angular coefficients that were not statistically different, i.e. matrix effect was absent for both matrices then the calibration for the three matrices was accomplished with aqueous calibration. The accuracy was checked with six certified materials for bovine liver; four for salmon and two for rolled oats. In all cases, obtained values were in agreement with the certified one. The characteristic masses were of 8.0, 6.4, and 7.8 for bovine liver, salmon and rolled oats, respectively (recommended mass of 10 pg). The LOD and LOQ were of 1.8 and 6.0 μg g− 1 for bovine liver, 2.0 and 6.6 μg g− 1 for salmon and 1.4 and 4.6 μg g− 1 for rolled oats. As the solubilisation is very fast, the methods can be used to determine Cu (and most probably other metals) with simple sample preparation, good accuracy and precision.