Application of porous membrane protected micro-solid-phase-extraction combined with gas chromatography-mass spectrometry for the determination of estrogens in ovarian cyst fluid samples

A cost effective and environmentally friendly extraction technique using porous membrane protected micro-solid phase extraction (μ-SPE) is described for the extraction of estrogens in cyst fluid samples obtained from cancer patients. A sorbent (ethylsilane (C2) modified silica) (20mg) was packed in a porous polypropylene envelope (2cm×1.5cm) whose edges were heat sealed to secure the contents. The μ-SPE device was conditioned with acetone and placed in a stirred (1:5) diluted cyst fluid sample solution (10mL) to extract estrogens for 60min. After extraction, the analytes were desorbed and simultaneously derivatized with a 5:1 mixture of acetone and N,O-bis(trimethylsilyl)-trifluoroacetamide. The extract (2μL) was analyzed by gas chromatography-mass spectrometry. Various extraction, desorption and derivatization conditions were optimized for μ-SPE. With this simple technique, low limits of detection of between 9 and 22ngL^-1 and linear range from the detection limits up to 50μgL^-1 were achieved. The optimized method was used to extract estrogens from cyst fluid samples obtained from patients with malignant and benign ovarian tumors.