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 AND 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 wasstudied. The samples were introduced directly as oil-in-water emulsions in a flow injection manifoldfollowed by cold vapor generation coupled to atomic fluorescence spectrometry (FI-CV-AFS). Afterirradiation with an UV source, organic mercury (e.g. MeHg+ and PhHg+ among others) wasdecomposed. Mercury vapors were generated using an acidic SnCl2 solution in a continuous flowsystem and were then determined. This strategy reduced sample handling, avoiding samplecontamination and analyte losses. The limit of detection was calculated as 0.2 mg Kg1 (0.03 mg L1 forthe emulsions) and the relative standard deviation was better than 8% at levels of 3.0 mg L1 in theemulsion, calculated from the peaks obtained. The accuracy was verified by comparing the results witha total microwave-assisted digestion.