Ultrasonic-assisted Acid Digestion Prior to Determination of Iron, Zinc and Nickel in Chicken Gizzard

Abstract

Trace metals are widely determined in various type of samples such as in industrial wastewater, sewage, soil sediment, poultry or in plants. Many analytical methods are focusing on sample preparation procedure to increase the efficiency of the extraction. Sample preparation is the most time-consuming part of analysis where the samples must be homogeneous. Most conventional techniques such as hot plate and dry ashing are aided with high temperature to aid in the solid sample’s dissolution. Hence, the use of ultrasonic-assisted acid digestion has been recently developed as an efficient method for digestion of trace metals in biological sample. It is an alternative technique to conventional sample pre-treatment methods for shortened and simplified procedure prior to the measurement. Trace metals (Fe, Ni, and Zn) extracted from chicken gizzard samples using ultrasonic bath were determined by flame atomic absorption spectroscopy (FAAS). Three parameters which are type of solvents, time of sonication and weight of sample were studied using ultrasonic bath to obtain the optimum digestion condition. The optimized parameters (HNO3 - HCl solvent mixtures, 40 minutes sonication time and 0.2 g of sample weight were utilized to further analyzed trace metals in chicken gizzard. The concentration of Fe, Zn and Ni were successfully determined with values of (238.107 ± 0.019) mg/kg, (91.754 ± 0.061) mg/kg, and (335.813 ± 0.011) mg/kg respectively. For repeatability study, both intraday and interday measurement were 1.15% and 1.66% respectively. Optimization of ultrasonic-assisted acid digestion can be useful to increase the efficiency of the metal’s digestion in biological samples prior to the determination by FAAS.