Total and inorganic mercury determination in biodiesel by emulsion sample introduction and FI-CV-AFS after multivariate optimization

PEDRO R. ARANDA; PABLO H. PACHECO; ROBERTO A. OLSINA; LUIS D. MARTINEZ; RAÚL A. GIL

JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY

ROYAL SOC CHEMISTRY

Año: 2009 p. 1441 - 1445

0267-9477

An automated procedure for total and inorganic mercury determination in biodiesel by CV-AFS was studied. The samples were introduced directly as oil-in-water emulsions in a flow injection manifold followed by cold vapor generation coupled to atomic fluorescence spectrometry (FI-CV-AFS). After irradiation with an UV source, organic mercury (e.g. MeHg+ and PhHg+ among others) was decomposed. Mercury vapors were generated using an acidic SnCl2 solution in a continuous flow system and were then determined. This strategy reduced sample handling, avoiding sample contamination and analyte losses. The limit of detection was calculated as 0.2 mg Kg-1 (0.03 mg L-1 for the emulsions) and the relative standard deviation was better than 8% at levels of 3.0 mg L-1 in the emulsion, calculated from the peaks obtained. The accuracy was verified by comparing the results with a total microwave-assisted digestion.