Determination of Copper in Human Hair and Tea Samples after Dispersive Liquid-Liquid Microextraction Based on Solidification of Floating Organic Drop (DLLME-SFO)

A simple method of dispersive liquid-liquid microextraction-solidified floating organic drop (DLLME-SFO) prior to flame atomic absorption spectrometry was successfully used for separating and preconcentrating copper in human hair and tea samples. The proposed method was simple, cheap, and has high precision. In this study, optimization of experimental parameters influencing the extraction, such as type and volume of extraction and disperser solvents, pH, the amount of chelating agent and extraction time was normally carried out using a step-by-step approach, in which each factor was varied sequentially. The effect of the interfering ions on the analytes recovery was also investigated. The calibration graph was linear in the range of 5-200 ng mL(-1) with limit of detection of 3.4 ng mL(-1). The relative standard deviation (RSD) was 0.7% (n = 10, C = 2 ng mL(-1)) and the enhancement factor was 28.