A portable analytical system for the rapid on-site analysis of fluids, and a method for using this system at the well-site for the analysis of samples extracted from drilling fluids is described. The portable analytical solution may be deployed at the well-site and used to perform detailed real-time analysis of formation fluids and extracts of rock cuttings. The method described could be used during hydrocarbon exploration and production to determine whether the drill stem has passed through a hydrocarbon-bearing region, or rocks that are capable of functioning as an oil reservoir or that may have been a source rock, or that may have come into contact with oil, or that may contain oil at present.