Online solid phase extraction-HPLC-ICP-MS system for mercury and methylmercury preconcentration using functionalised carbon nanotubes for their determination in dietary supplements

• Published in: Journal of Analytical Atomic Spectrometry
• Main Authors: Londonio, Juan Agustín, Hasuoka, Paul Emir, Pacheco, Pablo Hugo, Gil, Raul Andres, Smichowski, Patricia Nora
• Format: Article in Journal/Newspaper
• Language: English
• Published: Royal Society of Chemistry
• Subjects: Mercury speciation; carbon nanotubes; flow injection analysis; LC-ICPMS; https://purl.org/becyt/ford/1.4; https://purl.org/becyt/ford/1; Antarctic; Argentina; San Martín; Pablo; Antarc*
• Online Access: http://hdl.handle.net/11336/87358

A hyphenated system was developed for Hg(ii) and methylmercury (MeHg) preconcentration and speciation analysis by the online coupling of solid phase extraction (SPE), high performance liquid chromatography (HPLC) and inductively coupled plasma mass spectrometry (ICP-MS). Both analytes, Hg(ii) and MeHg, were preconcentrated on a microcolumn filled with multiwalled carbon nanotubes (MWCNTs) functionalised with poly-l-methionine (polymet-MWCNTs). During the method development the sorbent material was carefully studied and the solid phase extraction conditions were optimised. An enrichment factor of 190 for Hg(ii) and MeHg was obtained when 20 mL of sample was passed through the microcolumn. For the chromatographic separation, a mobile phase composed of a ternary mixture of 0.5% formic acid + 0.2% 2-mercaptoethanol + 20% methanol was used. Separation of both mercurial species was accomplished in ∼10 min on a 250 mm C18 column. The detection limits of the SPE-HPLC-ICP-MS method were 15 ng L−1 for Hg(ii) and 17 ng L−1 for MeHg. The relative standard deviations of peak area for 5 ng L−1 of each Hg species were below 5%. Recoveries of Hg(ii) and MeHg were never less than 93%. For checking the accuracy, BCR 643-tuna fish and TORT-3 lobster hepatopancreas certificate reference materials were analysed. Mercury species were determined in spiked fish oil-based dietary supplements and Antarctic water. Fil: Londonio, Juan Agustín. Comisión Nacional de Energía Atómica; Argentina. Universidad Nacional de San Martín. Instituto de Investigación en Ingeniería Ambiental; Argentina Fil: Hasuoka, Paul Emir. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; Argentina Fil: Pacheco, Pablo Hugo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San ...