a b s t r a c t
In this study, asample preparationmethod based onultrasonic 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.