Linear retention index approach applied to liquid chromatography coupled to triple quadrupole mass spectrometry to determine oxygen heterocyclic compounds at trace level in finished cosmetics

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 instrumental setup and the employed method were the same previously developed and validated [ 52 ].…”

“…Peak identification was carried out by complementarily using the MS/MS library and the LRI database, as reported in the previous work [ 52 ]. The homologous series of alkyl aril ketones was injected before the samples and used for the calculation of the LRI values by means of the following equation, according to the Van den Dool and Kratz theory and as previously reported [ 51 , 52 , 59 ]: where z is the carbon number of the alkyl aryl ketone eluted before the analyte, t Ri , t Rz and t R ( z +1) are the retention times of the analyte and the alkyl aryl ketones eluted before and after the analyte.…”

“…However, in derived food or cosmetics products, viz. for target analysis in complex samples, more sensitive and selective methods are needed, mainly based on the use of tandem MS systems that allow to achieve low limits of quantification (LOQ) [ 1 , 2 , 20 , 52 , 53 , 54 , 55 ].…”

“…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. Indeed, the built LRI databases proved to be stable in different instrumental setups [ 51 , 52 , 55 ].…”

“…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. Indeed, the built LRI databases proved to be stable in different instrumental setups [ 51 , 52 , 55 ]. Within this context, the present research was aimed to characterize several citrus beverages and a marmalade sampled by HPLC-MS/MS; thus, combining the use of an MS/MS library and the LRI database for a reliable identification, even at trace level, below the limit of identification of the common UV detectors.…”