Determination of phthalate esters in physiological saline solution by monolithic silica spin column extraction method

Monolithic silica spin column extraction (MonoSpin-SPE) was developed as a simple, sensitive, and eco-friendly pretreatment method which combined with ultra-fast liquid chromatography-mass spectrometry (UFLC-MS) to determine the levels of six phthalate esters, dimethyl-(DMP), diethyl-(DEP), dipropyl-[DPrPJ], butyl-benzyl-(BBP), dicyclohexyl-(DcHP), and di-n-octyl-(DOP) phthalate in physiological saline samples. Under optimized experimental conditions, the method was linear in the following ranges: 0.2 - 50 mu g/L for DMP, DEP, DPrP, DcHP and OOP; 5 - 100 mu g/L for BBP. The correlation coefficients (R-2) were in the range of 0.9951 - 0.9995 for all the analytes and the limits of detection (LODs) and limits of quantification (LOQs) were in the ranges of 0.02 - 0.9 mu g/L and 0.08 - 2. 7 mu g/L, respectively. The pretreatment process showed good reproducibility with inter-day and intra-day relative standard deviations (RSDs) below 8.5% and 11.2%, respectively. This method was used to determine the levels of six phthalate esters in physiological saline samples and the recoveries ranged from 71.2% to 107.3%. DMP and DEP were found in actual physical saline samples (brand A and brand B).