Abstract
A dispersive liquid-liquid microextraction (DLLME) procedure for determination of Pb(II) in water and tobacco samples has been developed using rac-(E,E)-N,N'-bis(2-chlorobenzylidene)cyclohexane-1,2-diamine as a chelating agent. Factors influencing the efficiency of DLLME have been optimised, including metal solution pH, type and amount of dispersing solvent, type and amount of extraction solvent, amount of chelating agent and sample volume. The optimized conditions for maximum recovery were as follows: sample pH 6; dispersing solvent, 500 mu L of ethanol; extraction solvent, 150 mu L of chloroform; chelating agent, 150 mu L of 0.01% rac-(E,E)-N,N'-bis(2-chlorobenzylidene)cyclohexane-1,2-diamine; and sample volume, 15 mL. The method was validated using the certified reference material SPS-WW2 waste water. The method offered a limit of detection (LOD) of 2.6 mu g/L, a limit of quantification (LOQ) of 8.5 mu g/L, and a relative standard deviation (RSD) of 5.2%.