Emulsification solidified floating organic drop microextraction assisted by ultrasound for determination of nickel, cobalt and copper in oyster and fish samples
In the present work, Solidiﬁed ﬂoating organic drop microextraction assisted by ultrasound is proposed as preconcentration system for determination of trace amounts of nickel, cobalt and copper by F AAS. The main parameters such as pH, concentration of TAN, extraction time, sample and organic phase volume and the nature of the organic solvent, were optimized. This system has allowed for the determination of nickel, cobalt and copper with a detection limit LOD of 0.64, 0.86 and 0.57 g L-1 and a quantification limit (LOQ) (10σ/S) of 1.60, 1.05 and 1.17 g L-1. The precision expressed as relative standard deviation R.S.D of 2.67 and 2.65 for nickel, copper and cobalt, respectively. Accuracy was confirmed by determination of analytes in the standard reference material, NIST SRM tomato leaves 1573a and NIST 1577 bovine liver samples and spike tests with recoveries ranging from 96 to 104 %. The procedure was applied for nickel, cobalt and copper determination in tin oyster and fish samples.