A high‐sample‐throughput LC–GC method for mineral oil determination

The present investigation deals with a method improvement to increase data throughput and reduce solvent consumption for both saturated and aromatic mineral oil hydrocarbon determination using a coupled liquid–gas chromatographic system. The starting point of this work was the method proposed by Biedermann, Fiselier, and Grob in 2009. A total time and solvent reduction of 34 and 23%, respectively, was obtained by speeding up the GC run and reducing the LC‐reconditioning step. The band broadening, occurring in the LC column during stop‐flow in the multitransfer mode, was assessed by comparing the variances of the perylene peak width recorded in the stop‐flow and normal modes. Band broadening directly proportional to the stop time of the LC pumps was observed, however, it did not affect the analytical reliability. A series of real samples (paperboards and pasta) was analyzed obtaining comparable results using both the reference and proposed method, both in the normal and multitransfer modes.