Estrogens determination exploiting a SIA-LOV system prior in-port derivatization-large volume injection-programmable temperature vaporization-gas chromatography.

In this work, we present a method for the clean-up, preconcentration and quantification of the four most widely found estrogens (estrone E1, estradiol E2, estriol E3 and ethynyl estradiol EE2) in seawater samples. A sequential injection analysis-lab on valve system (SIA-LOV) has been developed to perform the microsolid phase extraction (µSPE) of the analytes in a fully automated way. After testing different resins and solvents, C18 resin with acetonitrile (ACN) as eluent have been chosen as they provided the best results. Several parameters affecting the extraction have been studied and optimized. Besides, extraction column lifetime has also been checked as it is indicative of the number of consecutive analysis that the column is able to perform before replacing it. Results showed that the same column can be used up to 50 times. Then, the derivatization of the extracts has been performed unattended by exploiting an in-port derivatization of the analytes with N-methyltrimethylsilyltrifluoroacetamide (BSTFA) prior their quantification using large volume injection with programmable temperature vaporization gas chromatography (LVI-PTV-GC-MS).