The retention index approach in liquid chromatography: An historical review and recent advances

Dietary Intake of Coumarins and Furocoumarins through Citrus Beverages: A Detailed Estimation by a HPLC-MS/MS Method Combined with the Linear Retention Index System

“…The LRI system is routinely used in gas chromatography since it has been introduced for the first time [ 56 ]; it was abandoned after a few attempts in LC due to a poor repeatability at inter-laboratory levels [ 57 ]. Recently, it was re-proposed in our laboratory for the identification of lipids [ 58 ] and OHC compounds [ 51 , 52 , 59 ] through LC methods combined with different detection systems, being confident about the highest batch-to-batch reproducibility of LC columns and instrumentations achieved in the last years.…”

Elucidation of the Lipid Composition of Hemp (Cannabis sativa L.) Products by Means of Gas Chromatography and Ultra-High Performance Liquid Chromatography Coupled to Mass Spectrometry Detection

“…It is noteworthy that the Δ value between the experimental and tabulated LRI values (LRI exp and LRI tab , respectively) for almost all the compounds remained inside the tolerance window of ± 15 units, as derived from previous calculation about the separation number of the applied chromatographic method [ 19 , 21 ]. Out of a total of 62 identified compounds, 31 TAGs were positively matched with the LRI database (ΔLRI ≤ 15), and an additional 4 TAGs differed from the tabulated values of 17–20 units, mainly due to coelutions or very low peak intensity.…”

“…Particularly, each odd carbon chain number reference compound is eluted few seconds earlier or later than the subsequent or previous even carbon chain number TAG. Moreover, it can be highlighted that even PN regions, as well as the reference TAGs are quite equidistant from each other under the linear gradient used for the LC separation, thus, guaranteeing the proper functioning of the LRI strategy [ 21 ].…”

“…The present work aimed at the evaluation of the lipid composition of different hemp-derived products (seed oil, seed flour and seed flour residue) by means of GC-FID/MS and LC-MS analytical methods. Moreover, a recently introduced linear retention index (LRI) approach in LC [ 19 , 21 ] was employed to achieve a reliable identification of TAGs in the examined samples. In this way, the identification process in LC was based on a dual filter approach that is quite similar to GC-MS methods.…”

“…In this way, the identification process in LC was based on a dual filter approach that is quite similar to GC-MS methods. It exploits the complementarity between the information obtained from mass spectra and retention data in the form of LRI, which is a parameter as independent as possible from operating conditions so that it is reproducible at both intra- and inter-laboratory levels [ 21 ].…”