Bisphenol A can be detected by using a C18 Column and waters/ACN as mobile phases. Detection at 230 nm with UV. You can find many publications about this.
You will need to check which is the concentration you want to reach if not enough you will need to introduce a SPE pre-concentration step.
Use a mobile phase with ACN/ 0.1% TFA ( or acetate buffer) either use a gradient run or an isocratic one as per your available C18 column specification.
Use a multipoint assay concentrations with appropriate range and linearity limits based on your sample concentrations.