Sample preparation is the most time consuming part of elemental analysis where homogeneous samples that are almost free from organic matter is necessary. Therefore, preliminary operations such as separation of interferents and preconcentration of the analytes are required prior to analysis. Ultrasonic digestion recently proposed as an efficient method for extraction of trace metals from solid samples. The ultrasonic digestion was optimized by using two parameters whilst another two other parameters were used in enzymatic digestion. Conventional one-variable-at-a-time (OVAT) optimization method was applied to both digestion techniques. Fe and Zn were extracted from the samples and were determined by using flame atomic absorption spectrometry (FAAS).The combination of ultrasonic and enzymatic digestion techniques is known as Ultrasonic-Assisted Enzymatic Digestion (USAED) method. The ultrasonication equipment used was ultrasonic bath. Four parameters studied for optimization were sample mass, sonication time, protease enzyme volume and incubation time. The optimum condition of parameters for sample mass was 0.2 g, sonication time of 30 min whilst for enzyme volume was 1000 µL and for incubation time of 24 hours. For the kinetic study, these reactions had undergone zero order reaction. This USAED method was successfully applied for the digestion and kinetic study of the cockle samples
