Sugaring-out assisted extraction (SoAE): A novel approach for the determination of Cd and Pb in milk by graphite furnace atomic absorption Spectrometry.

BACKGROUND

Milk and dairy products are significant from both nutritional and economic perspectives. As a result, they are subject to strict health surveillance and quality control protocols, making the development of reliable analytical methods a critical concern in the food industry. Due to the complex and variable chemical composition of milk matrix, sample preparation steps are often essential prior to the determination of metals using spectroanalytical techniques.

RESULTS

This study introduces a novel sample preparation method for the determination of Cd(II) and Pb(II) in milk, based on extraction assisted by the sugaring-out effect (SoAE), using acetonitrile as the extraction solvent. Quantification of the analytes in the extracts was carried out using Graphite Furnace Atomic Absorption Spectrometry (GF AAS). The optimized method achieved limits of quantification (LoQs) of 0.24 μg kg for Cd(II) and 1.3 μg kg for Pb(II), with enhancement factors of 7.5 and 9, respectively. These LoQs are well below the maximum allowable limits for these contaminants in milk (50 μg kg for Cd(II) and 10 μg kg for Pb(II)), confirming the suitability of the method for routine quality control. The method was rigorously validated in accordance with requirements set by international regulatory bodies. Its accuracy, evaluated using a certified reference material (CRM), was 106 % for Cd(II) and 91.8 % for Pb(II).

SIGNIFICANCE

The proposed method is novel, using the sugaring-out effect (SoAE) for the first time in metal determination of complex aqueous samples. It offers simplicity, speed, and accurate Cd(II) and Pb(II) determination without interferences. The SoAE approach shows promise for broader applications, including the separation and determination of other metals or organics in combination with various spectroscopic, chromatographic, and electroanalytical techniques.