Abstract
In this thesis, we combined dynamic liquid-liquid-liquid microextraction (LLLME) with multi-elements graphite furnance atomic absorption spectrometry (GFAAS) to determine trace lead and cadmium in water samples. In the extraction step, two elements in 30 mL of the water sample which adjusted to pH 5 (donor phase) were extracted into an organic film containing a chelating agent (1 % dithizone) in 4-nitro-m-xylene and then back-extracted to 5 μL, 10 % nitric acid solution (acceptor phase). 4.5 μL acceptor phase and 0.5 μg palladium (chemical modifier) were injected into the graphite tube by syringe simultaneously. The continual movement of organic and acceptor phases not only resulted in a renewable organic film but also enhanced the enrichment factor. Under the optimized conditions (ashing temp. 600℃, atomization temp. 2000℃, stirring rate 700 r.p.m., extraction time 40 minutes), the detection limits and relative standard deviations (RSDs) were 0.032 ng/mL, 0.037 ng/mL ; 7%, 4% for lead and cadmium, respectively.