Dual wavelength thermal lens spectroscopy as a detection system in microchip for determination of mercury after rotative liquid-liquid microextraction

It is first time that a dual wavelength (DW) laser was used as a source in thermal lens spectroscopy (TLS). In that way, one wavelength acts as excitation beam and the other acts as probe beam. The biggest advantage of this system is having high sensitivity of dual-beam method [1] and it has the simplicity of single beam method at the same time. We perform DWTLS as a detection system in a glass microchip [2] for determination the trace amount of mercury in environmental samples after rotative liquid-liquid microextraction (RLLME) [3]. Dithizone was used as a chelating agent that extract mercury in organic phase [4]. In this step extraction solvent, pH, dithizone concentration, solvent value, extraction time and salt concentration was optimized. This method was used for determination of mercury in many samples such as tap water, well water, seawater and industrial waste water that a high percentage of recovery achieved.