Development of a Novel and Robust Hyphenated Method Called DLLME/LI-TLS for Trace Analysis of Cd in Water and Drug Samples

Cadmium is one of the most hazardous elements in human health. Dispersive Liquid-Liquid Microextraction / Laser Induced-Thermal Lens Spectrometry (DLLME/LI-TLS) was developed as a new combination method for preconcentration and determination of Cd in water, juices, and drug tablets. Thermal lens spectrometry is suitable for the determination of analyte after DLLME because of the low volume of the remained phase after DLLME and increasing of the enhancement factor for the nonpolar organic solvents. Some effective parameters on the microextraction, complex formation, and combination were selected and optimized. Under optimum conditions, the calibration graphs were linear in the range of 0.1-20 µg/L with the detection limit of 0.01 µg/L. The relative standard deviation (RSD) for 1 and 10 µg/L of cadmium was 3.2 and 2.5, respectively. The enhancement factor of 700 was obtained from a sample volume of 10.0 mL and a determination volume of 25 µL. DLLME/LI-TLS method was applied to the analysis of juices, drug tablets, and real water samples. The accuracy of the method was proved by using standard reference materials and microspectrophotometry.