The use of triton X-100 in thermal lensing of aqueous solutions

The ability of Triton X-100 to affect thermooptical parameters of water is used for determining the surfactant by thermal lensing. The limit of detection of Triton X-100 in the presence of pre-synthesized cobalt(III) tris-(2-nitroso-1-naphtholate) as an inert colorant is 8x10(-4) mol dm(-3), which is close to the critical micelle concentration of the surfactant. A method for estimating the limits of detection of thermal lensing in a given solvent system based on the reproducibility of measurements for a single sample is developed. In this approach, Triton X-100 is applied for enhancing the sensitivity of thermal lensing in aqueous solutions. For the concentrations of Triton X-100 of 0.04-0.1 mol dm(-3), a twofold enhancement in detection limits of iron(II) with 1,10-phenanthroline and cobalt(III) with 2-nitroso-1-naphthol as model systems without any change in the sample preparation is observed.