The present invention is directed to methods of evaluating a process to produce a polypeptide preparation or evaluating an element of a process to produce a polypeptide preparation. The methods comprise providing a sample comprising the polypeptide, wherein the sample has not been subjected to affinity chromatography, and subjecting the sample to liquid chromatography. The sample may be a process bioreactor sample. The methods of the invention may be used to determine a value of a characteristic of the sample. The methods of the invention provide a real time or near real-time information regarding the process to produce a polypeptide.