Microextraction based on solidified floating organic drop coupled with ETAAS for the determination of lead in herbs

A rapid, inexpensive and practical solidified of floating organic droplet microextraction (SFODME) prior to electrothermal atomic absorption spectrometry (ETAAS) was proposed for lead (Pb) determination in herb samples. For SFODME procedure, 1-(2-pysidylazo)-2-naphthol was used as a complexing agent. Analytical parameters influencing the extraction efficiency, i.e. types and volume of extracting solvent, concentration of 1-(2-pyridylazo)-2-naphthol, pH, extraction temperature and time were optimized. Under the optimized conditions, LOD and LOQ were 0.064 and 0.214 μg L−1, respectively, and an enrichment factor was achieved at 18.71 with the relative standard deviation ranging from 1.3 to 2.5% (n=6). The proposed method was effectively applied to the determination of lead in Spinach leaves (SRM-1570a) and Thai herb samples with acceptable results