Packed-fiber solid-phase extraction coupled with high performance liquid chromatography–tandem mass spectrometry for determination of diethylstilbestrol, hexestrol, and dienestrol residues in milk products

• A method based on packed-fiber solid-phase extraction (PF SPE) has been established for the determination of three estrogenic stilbenes in dairy products.
• Samples were pretreated with PF SPE using an electrospun nanofiber cartridge before analysis by RRLC–MS/MS.
• Parameters affecting the efficiency of PF SPE, including pH and salt concentration, were investigated and optimized.
• The developed method was successfully applied for the determination of stilbenes in 69 milk samples.
• The method has proved to be sensitive and cost-effective in stilbene detection.

A sensitive analytical method based on packed-fiber solid-phase extraction and high performance liquid chromatography–tandem mass spectrometry (PF SPE-HPLC–MS/MS) has been developed for determination of three synthetic stilbenes in milk. The stilbenes are extracted with acetonitrile, using sodium chloride, and purified with PF SPE using a cartridge containing electrospun polystyrene nanofibers. Parameters affecting the efficiency of PF SPE, such as pH and amount of salt, were optimized. Under optimal conditions, the limits of detection and quantification were 5–13 pg/g and 15–37 pg/g, respectively. Absolute recoveries varied between 60% and 85% at three different levels. The method was successfully applied for the determination of estrogenic stilbenes in a total of 69 milk samples. The method is sensitive and cost-effective in stilbene detection, and has potential in quality control of dairy products.