Determination of trace elements in B5-diesel oil by HR-CS ET AAS using a simple dilute-and-shoot approach

摘要

This work describes a simple, fast and sensitive procedure for the determination of Al, Cd, Cu, Fe, Pb and Mn in commercial B5-diesel oil samples using high-resolution continuum source electrothermal atomic absorption spectrometry (HR-CS ET AAS). The procedure consists on simple dilution of the samples using n-propanol, with further acidification with HNO3. Calibration against aqueous standards could be employed for the determination of Cu, Fe, Pb and Mn, whereas calibration solutions prepared in n-propanol were required for the determination of Al and Cd. The pyrolysis and atomization curves were investigated for the analytes prepared in aqueous solutions and for the B5-diesel oil samples. A study involving the use of modifiers was carried out. 480 μg of Zr for Al, Mn and Pb determination and 500 μg of Ir for Cd determination were employed as permanent chemical modifiers. Pyrolysis temperatures of 700 °C for Cd, 800 °C for Pb and 1000 °C for the other elements were adopted. The atomization temperatures were optimized as 1500 °C for Cd, 1900 °C for Pb, 2300 °C for Cu, Fe and Mn and 2500 °C for Al. The limits of quantification were determined as 0.001 μg g-1 for Cd and Mn, 0.002 μg g-1 for Pb, 0.006 μg g-1 for Fe and 0.01 μg g-1 for Al and Cu. Recovery tests resulted in recovery values between 89 and 120% for diesel oil samples. The method has proved to be fast, precise and accurate.