One-pot synthesis of a magnetic nanocomposite based on ultrasound-assisted co-precipitation for enrichment of Hg(II) prior to detection by a direct mercury analyzer

Inmaculada de la Calle; Javier Páez-Cabaleiro; Isela Lavilla; Carlos Bendicho

doi:10.1016/j.talanta.2019.02.085

One-pot synthesis of a magnetic nanocomposite based on ultrasound-assisted co-precipitation for enrichment of Hg(II) prior to detection by a direct mercury analyzer

Talanta. 2019 Jul 1:199:449-456. doi: 10.1016/j.talanta.2019.02.085. Epub 2019 Feb 26.

Authors

Inmaculada de la Calle¹, Javier Páez-Cabaleiro², Isela Lavilla², Carlos Bendicho³

Affiliations

¹ Departamento de Química Analítica y Alimentaria, Área de Química Analítica, Facultad de Química, Universidad de Vigo, Campus As Lagoas-Marcosende s/n, 36310 Vigo, Spain. Electronic address: incalle@uvigo.es.
² Departamento de Química Analítica y Alimentaria, Área de Química Analítica, Facultad de Química, Universidad de Vigo, Campus As Lagoas-Marcosende s/n, 36310 Vigo, Spain.
³ Departamento de Química Analítica y Alimentaria, Área de Química Analítica, Facultad de Química, Universidad de Vigo, Campus As Lagoas-Marcosende s/n, 36310 Vigo, Spain. Electronic address: bendicho@uvigo.es.

PMID: 30952282
DOI: 10.1016/j.talanta.2019.02.085

Abstract

Ultrasound-assisted co-precipitation was applied to construct a magnetic nanocomposite following a 'one-pot' synthetic strategy for Hg(II) enrichment. The presence of a noble metal such as Ag(I), Au(III), Pd(II) in the synthesis medium proved to be essential in order to attain an efficient co-precipitation of Hg with the magnetic nanoparticles. Following this preconcentration procedure, thermal desorption and a further preconcentration was carried out by amalgamation onto a gold coil placed inside a direct mercury analyzer working under the principle of atomic absorption. The magnetic nanocomposite was characterized by transmission electron microscopy (TEM), high-resolution transmission electron microscopy coupled to energy dispersive X-ray spectrometry (HR-TEM-EDS) and total reflection X-ray fluorescence (TXRF). Magnetic nanoparticles with a size in the range of ca. 7-11 nm were obtained. After full optimization of variables influencing the preconcentration and detection of Hg, analytical characteristics were obtained. A detection limit as low as 3.2 ng/L Hg was obtained when 50 µL of the magnetic phase were introduced in the mercury analyzer. The repeatability and reproducibility expressed as relative standard deviation (RSD) were 7% and 10%, respectively. Several certified reference materials, synthetic and unknown water samples were analyzed showing Hg recoveries in the range of 88-115%.

Keywords: Direct mercury analyzer; Magnetic phase; Mercury enrichment; One-pot synthesis; Ultrasound-assisted co-precipitation.