Method development for Cd and Hg determination in biodiesel by electrothermal atomic absorption spectrometry with emulsion sample introduction

• Published in: Talanta (Oxford) 2012-11, Vol.101, p.353-356
• Main Authors: Aranda, Pedro R., Gásquez, José A., Olsina, Roberto A., Martinez, Luis D., Gil, Raúl A.
• Format: Article
• Language: English
• Subjects: Analytical chemistry; Atomic absorption analysis; Biodiesel; Biofuels - analysis; Cadmium; Cadmium - analysis; Cadmium determination; Calibration; Chemistry; Electrothermal atomic absorption spectrometry; Emulsion sample introduction; Emulsions; Exact sciences and technology; Firing; Limit of Detection; Mathematical analysis; Mercury; Mercury - analysis; Mercury determination; Spectrometric and optical methods; Spectrophotometry, Atomic - methods; Strategy
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2012.09.038

A novel method for analysis of biodiesel by electrothermal atomic absorption spectrometry is described. This analytical strategy involves sample preparation as emulsions for routine and reliable determination of Cd and Hg. Several experimental conditions were investigated, including emulsion stability and composition, furnace temperature program and matrix modification. Different calibration strategies were also evaluated, being the analyte addition method preferred both for Cd and Hg. The accuracy was verified through comparison with an acid digestion in a microwave closed system. The injection repeatability was evaluated as the average relative standard deviation (R.S.D %) for five successive firings and was better than 4.4% for Cd and 5.4% Hg respectively. The detection limits, evaluated by the 3σ concept of calculation (n=10), were of 10.2μgkg−1 (0.9μgL−1) for Hg and 0.3μgkg−1 (0.04μgL−1) for Cd. This method was successfully applied to the determination of Cd and Hg in biodiesel samples obtained from local vendors. ► Sample preparation as emulsions for routine determination of Cd and Hg in biodiesel. ► This method joins the excellent sensitivity attainable by ETAAS. ► Advantage of this procedure is the stability and ease of sample handling ► This simple and fast method enables the use of aqueous standards for calibrations. ► Use of organ metallic standards or toxic solvents is no needed.