Selective determination of estrogenic compounds in water by microextraction by packed sorbents and a molecularly imprinted polymer coupled with large volume injection-in-port-derivatization gas chromatography–mass spectrometry

A fully automated protocol consisting of microextraction by packed sorbents (MEPS) coupled with large volume injection-in-port-derivatization-gas chromatography–mass spectrometry (LVI-derivatization-GC–MS) was developed to determine endocrine disrupting compounds (EDCs) such as alkylphenols, bisphenol A, and natural and synthetic hormons in river and waste water samples. During method optimization, the extraction parameters as ion strength of the water sample, the MEPS extraction regime, the volume of organic solvent used for the elution/injection step, the type of elution solvents and the selectivity of the sorbents were studied. For optimum in-port-derivatization, 10 μL of the derivatization reagent N,O-bis(trimethylsilyl)triufloroacetamide with 1% of trimethylchlorosilane (BSTFA + 1% TMCS) was used. 17β-Estradiol-molecularly imprinted polymer (MIP) and silica gel (modified with C-18) sorbents were examined for the enrichment of the target analytes from water samples and the obtained results revealed the high selectivity of the MIP material for extraction of substances with estrogen-like structures. Recovery values for most of the analytes ranged from 75 to 109% for the C18 sorbent and from 81 to 103% for the MIP material except for equilin (on C18 with only 57–66% recovery). Precision (n = 4) of the entire analysis protocol ranged between 4% and 22% with both sorbents. Limits of detection (LODs) were at the low ng L−1 level (0.02–87, C18 and 1.3–22, MIP) for the target analytes.

Figure optionsDownload as PowerPoint slideHighlights
► We developed a fully automated at-line MEPS-LVI in-port-derivatization-GC–MS method.
► The analytes were detected in the μg L−1–ng L−1 range with only 800 μL of sample.
► A high selectivity of the MIP material for estrogens’ recognition was demonstrated.
► Compared to a normal SPE, the time for a MEPS extraction is reduced to about 10 min due to the high automation and miniaturization grade.
► Less matrix co-extraction was of special value for analysis of wastewater samples.