We are manufacturing a product which contains betamethasone. In the end-point of exhaust air duct, we use a H13 filter. Our government requires that it should be no betamethasone residue found in the exhaust air. LOD of betamethasone in our best available method is 0.06 µg/ml (methanol solvent).
Can anyone suggest me the method to test betamethasone in exhaust air?