The present disclosure discusses a method of separating a sample (e.g., pharmaceutical drug, genotoxic impurity, biomarker, and/or biological metabolite) including coating a metallic flow path of a chromatographic system; injecting the sample into the chromatographic system; flowing the sample through the chromatographic system; separating the sample; and analyzing the separated sample using mass spectroscopy. In some examples, the coating applied to the surfaces defining the flow path is non-binding with respect to the sample—and the separated sample. Consequently, the sample does not bind to the low-binding surface of the coating of the flow path. The applied coating can increase the chromatographic peak area for the sample of the chromatographic system.