A novel isotope dilution UHPLC-ESI-MS/MS method for the quantification of 3-monochloropropane-1,2-diol in Caco-2 cell transport and receiving buffers

A routine, selective and sensitive ultra-high performance liquid chromatography-electrospray ionisation tandem triple quadrupole mass spectrometry (UHPLC-ESI-MS/MS) method was developed and validated for the quantification of 3-monochloropropane-1,2-diol (3-MCPD) in Caco-2 cell transport buffer (FaSSIF-V2, the second version of a fasted state simulated intestinal fluid) and receiving buffer (HBSS, Hank's balanced salt solution). The method involves measuring deuterated 3-MCPD (3-MCPD-d5) as internal standard (IS) during the entire analytical procedure to obtain precise and accurate results. The separation was performed on a Poroshell 120 HILIC column (2.7 mu m, 3.0 x 50 mm) at a flow rate of 0.3 mL/min using water (containing 0.025% acetic acid) and acetonitrile (containing 0.025% acetic acid) as the mobile phases. Mass spectrometric detection was operated in dynamic multiple reaction monitoring (dMRM) in negative ion mode. The method exhibited high sensitivity. The limits of detection (LOD) for 3-MCPD in FaSSIF-V2 and HBSS were 0.012 and 0.014 mu mol/L, and the limits of quantification (LOQ) were 0.039 and 0.045 mu mol/L, respectively. Satisfactory results were observed for linearity (R-2 > 0.999), intra-day precision (RSD% <7.7% in FaSSIF-V2 and <6.6% in HBSS), inter-day precision (RSD% <5.9% in FaSSIF-V2 and <5.6% in HBSS), accuracy (% error within +/- 10%), and sample stability (RSD% <7.7% and % error within +/- 10%). The method has been successfully applied to quantify 3-MCPD in Caco-2 cell transport and receiving buffers. The results were in good agreement with those obtained with gas chromatography-tandem mass spectrometry (GC-MS).