One would need more information to address this question properly.
What is the level of concentrations you are trying to measure (are these complexes of yours are well or poorly soluble?), is there any other species that may affect the measurements, what are the optical properties of these complexes (are they brightly colored or have characteristic absorption bands in UV or IR spectra that are not obscured by absorption bands of your solvents or other components of the mixture?)
Hi. You can check by IR or UV. If the complex solve, it give some peaks according to character of your complex. You can use ICP of AAS for certain results.
When you can visually see the solubility of a complex in a solvent of your choice, why do you need a device. If you get a clear solution without any suspended particles, assume it is soluble in that particular solvent.