Rinse volume

How to fix the rinse solvent volume of the equipment before sampling? is there any Science based calculation or assumption based? Please suggest…

The volume you have selected for rinsing should be enough to rinse the entire ‘product contact surface’. Since you consider the rinse volume in your calculation, it cannot make much difference in quantification of contaminant. But, if you select a more volume than the required, the sample may become more dilute and your testing equipment may be unable to detect the contaminant