The investigation of triadic silica-supported polyhexamethylene guanidine@nano-hydroxyapatite nanocomposites for Cr (VI) detection

Triadic silica-supported polyhexamethylene [email protected] (HAP) composites were prepared and employed in a micro-column system for solid phase extraction of Cr (VI) with its determination by flame atomic absorption spectrometry (FAAS). It is found that the triadic silica-supported nano-HAP composites can efficiently adsorb Cr (VI) at pH 4.0–6.0, but absorb almost no Cr (III). The detection has a good linear range of 0.3–300 μg L−1, a detection limit of 0.09 μg L−1 (3σ, n = 11) and a precision of 1.3% (20 μg L−1, n = 11) on Cr (VI). The adsorption mechanisms are mainly electrostatic attraction and the channel effect. This method was successfully applied to the determination of chromium contents in cereal and water samples with recoveries of 99.5–109.8%.