Development of Cr(III) analytical method in dairy products by cloud point extraction using graphite furnace atomic absorption spectroscopy

Cr(III) is one of chromium (Cr) metal ion species which is essential for human body because it has a significant influence on the metabolism of glucose, fat and protein. To specify the concentration of Cr(III), cloud point extraction was used as a method of separation and preconcentration which is low cost, fast and environmentally friendly. In this study, the analytical method development of Cr(III) in dairy products was performed using 1-(2-pyridylazo)-2-naphthol (PAN) ligand and nonionic surfactant Triton X-114 which was detected by Graphite Furnace Atomic Absorption Spectroscopy. Factors affecting the efficiency of extraction like pH of solution, concentration of ligand and surfactant, equilibration temperature and time were optimized to obtain the optimum extraction efficiency. Addition of Na₂SO₄ was also carried out to improve the extraction efficiency. The analysis of Cr(III) in dairy products which was previously treated with trichloroacetic acid produces precision with 4.1 % RSD and the recovery range of Cr(III) is of 80.0 to 100.8 %. The detection limit in dairy products obtained is 45 ng/g and the quantization limit is 150 ng/g. The enrichment factor after 125 times surfactant-rich phase dilution is of 2.1 and the preconcentration factor obtained is of 310.3. It is proved that the analytical method using cloud point extraction can be applied to specify the Cr(III) concentration in dairy products.