Determination of trace level metals in drinking and natural water samples and vegetables by using liquid-liquid micro extraction techniques

Metals and metalloids release to the environment from diverse natural and industrial sources. It is known that many metallic species have reverse effects on human health and environment. Some metallic species possibly existing in drinking water can be harmful to the human health even at trace and ultra-trace levels. Therefore, perpetual and reliable determination of these species in drinking waters is a must. Sensitive determination of metals is generally performed by different spectrometric methods, especially by atomic techniques. However there are so many challenges during trace and ultra-trace element analysis. The concentration of analyte is frequently lower than the limit of detection of the spectrometric technique to be used. Moreover, minute amounts of the metals are generally embedded in a complex matrix having properties to hinder a reliable determination (interferences). For these reasons a separation/pre-concentration step is frequently applied prior to instrumental analysis. Thus, it is provided not only concentration of the analyte to increase but also separation of the analyte from the matrix to prevent the interferences. Although the classical liquid-liquid extraction isa well known method for determination of metals at trace levels, the use of higher volume of solvent makes the method expensive, time consuming and labouring. Beside, the post-use solvents and other reagents bear a potential risk for the environment. All these drawbacks have resulted to the miniaturization of the classical liquid-liquid extraction method and the classical old techniques have been replaced by "liquid-liquid micro extraction" (LLME) techniques which can be applied in the manner of more effective, simple, economic and environmentally friend. However the LLME techniques have been applied mostly for determination of organic species. Whereas application to inorganicals are scarce and determination of metals have been mostly performed by the instrumental techniques such as ICP-MS, ICP-OES and GFAAS necessitating high instrument and operation costs and talented operators. In the proposed study, the application of LLME techniques for total metal determination and speciation studies will be examined but with the combined use of these techniques with the spectrophotometry (UV-VIS) which are quite economic and simple system.