EFFECT OF THE NATURE OF THE SOLVENT ON THE LIMIT OF DETECTION IN THERMAL LENS SPECTROMETRY

Owing to the thermal convection in thermal lens spectrometry the noise increases linearly with the signal. The slope, k, and the intercept o f the linear noise versus signal plots depend on the nature of the sol vent rather than the absorbing species. Attempts to correlate these pa rameters with the mechanical and thermo-optical properties of the solv ent are made. When the absorbance of a blank solution increases, the l imit of detection (LOD) increases proportionally to k. This decreases the differences between the LODs obtained in water and in other solven ts of better thermo-optical properties, but with higher values of k.