4. Conclusions
In this study, an effective method for preconcentration and determination of Cd (II) was developed. As a widely and com-monly used detection method, spectrophotometry was coupled with single drop microextraction, which largely minimized toxic organic solvents consumption and greatly increased the sensi-tivity for the determination of cadmium. Simplicity of operation, rapidity, low sample volume, low cost and high enrichment factor is some advantages of SDME. Spectrophotometric instrumentations own merits of simplicity, cheapness, portability and so on.
Through the hyphenation investigated in this work, the conventional spectrophotometer can accomplish trace and ultra-trace metal detection thus to expand its applications. The LOD of Cd
was better than those obtained by GF-AAS (0.7ngL−1)[7]. The rea-sons for the high sensitivity of Cd obtained in this work were the different maximum absorption wavelength induced by the different extraction acidity (pH value) and the sensitization of dilution solvent (acetone) to spectrophotometric determination. Besides considerably high preconcentration ability, the main advantages of the proposed method were environmentally benign, fast, simple and inexpensive. Trace and ultra-trace Cd (II) in several kinds of water and food samples could be determined with good repeatability and spiked recoveries