Criteria for Assessing the Effect of the Composition of Mixed Media on Analytical Sensitivity in Thermal Lens Spectrometry

The effect of the main parameters of solvent mixtures (water-acetone, water-ethanol, water-acetonitrile, water-ethylene glycol, and chloroform-acetone) of various compositions on the detection limit and analytical range was studied, and the selection criteria for the composition of mixed media were discussed in the context of trace determination by thermal lens spectrometry. It is shown that the strength of the thermal lens effect in the medium cannot serve the measure of its effect on the sensitivity and reproducibility of the determination. The lowest detection limits were reached in the water-ethanol (8 times lower in comparison to water), water-acetone (3 times), and water-ethylene glycol (2.5 times) mixtures with a volume ratio of components of 1: 4, while in water-acetonitrile mixtures (22 times), with a component ratio of 3 : 1.