A robust approach of QuEChERS combined with GC-MS technique for determination of three typical liquid crystal monomers in mouse serum and various tissues

Liquid crystal monomers (LCMs) are emerging organic pollutants to which humans are chronically exposed at low doses. Accurate quantification of LCMs in biological matrices remains challenging due to their low environmental concentrations and significant matrix effects. This study developed a novel approach for robust determination of three LCMs including 2,3-difluoro-4-(trans-4-propylcyclohexyl) butoxybenzene (3cH4OdFP), 4-propoxy-4′-cyanobiphenyl (3OCB), and 4-ethyl-4′-(4-propylcyclohexyl)-1,1′-biphenyl (3cH2B) in mouse serum, brain, heart, liver, spleen, lung, and kidney tissues. Serum samples were extracted with n-hexane, while tissues were extracted using acidified acetonitrile followed by QuEChERS cleanup.Separation was achieved on a DB-17HT column, and detection was performed in selected ion monitoring (SIM) mode of GC-MS. The method demonstrated good linearity (r² > 0.995) from 0.5 to 200 ng/mL. Limits of detection were 0.2 ng/g for tissues and 1.0 ng/mL for serum. Average recoveries ranged from 74.32% to 126.0%, with intra-day and inter-day precision between 2.165%-18.53% and 3.749%-19.13%, respectively. The validated method was successfully applied to exposed mice, revealing widespread tissue distribution of three LCMs, with the spleen showing a higher accumulation potential. This sensitive and reliable approach provides robust technical support for internal exposure assessment and toxicological studies of LCMs.