Evaluation of an ultrasonic acid digestion procedure for total heavy metals determination in environmental and biological samples

• Published in: Journal of hazardous materials Vol. 161; no. 2; pp. 1391 - 1398
• Main Authors: Kazi, Tasneem G., Jamali, Mohammad K., Arain, Mohammad B., Afridi, Hassan I., Jalbani, Nusrat, Sarfraz, Raja A., Ansari, Rehana
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 30.01.2009; Elsevier
• Subjects: Acids - analysis; Acids - chemistry; Animals; Applied sciences; Biological sample; Certified reference material; Environmental Monitoring - methods; Environmental sample; Exact sciences and technology; Fishes; Heavy metal; Ions; Metals, Heavy - analysis; Other industrial wastes. Sewage sludge; Pollution; Reference Values; Reproducibility of Results; Sewage; Soil Pollutants - analysis; Solvents; Spectrophotometry, Atomic - instrumentation; Spectrophotometry, Atomic - methods; Time Factors; Ultrasonics; Ultrasound energy; Wastes; Water Purification - methods; Ultrasound energy; Biological sample; Certified reference material; Environmental sample; Heavy metal; Sonication; Edible species; Sediments; Sewage sludge; Trophic chain; Sample preparation; Acid digestion; Reference material; Lead; Ultrasound; Atomic absorption spectrometry
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2008.04.103

In this study, a sample preparation method based on ultrasonic assisted acid digestion (UAD) has been evaluated for total heavy metals (Cd, Cr, Ni and Pb) determination in different environmental (soil, sediment and sewage sludge), and biological (fish muscles, vegetables and grains) samples, using electrothermal atomic absorption spectrometry (ETAAS). The investigated parameters influencing UAD such as presonication time, sonication time, temperature of ultrasonic bath, and different acid mixtures were fully optimized, whereas power was maintained constant at 100% of nominal power of ultrasonic bath. Six different sets of above parameters were applied on six certified reference materials (CRMs) having different matrices. The accuracy of the method was also tested by comparing the results with those obtained from conventional hot plate assisted acid digestion method on same CRMs. Analytical results for HMs by both methods showed no significant difference at 95% confidence limit ( p < 0.05). Recoveries of HMs ranging from 96.2% to 102% and 96.3% to 98.6% were obtained from biological and environmental samples, respectively. The average relative standard deviation of UAD method varied between 3.5% and 8.2%, depending on the analyte.