A systematic investigation to optimize simultaneous extraction and liquid chromatography tandem mass spectrometry analysis of estrogens and their conjugated metabolites in milk

Ultra-high-performance liquid chromatography-tandem mass spectrometry for the analysis of free and conjugated natural estrogens in cow milk without deconjugation

“…It is known that milk is a complex matrix containing a lot of possible interferents that can act at both extraction and detection level; therefore, low recovery and/or strong matrix effect are the main problems arising when a simple SPE was tested to determine free and conjugated metabolites in milk [10,20]. For this reason, usually the authors propose the deproteinization of milk as the first step in sample preparation methods, and then a fraction of the sample is cleaned up and analyzed, while a second fraction is deconjugated, cleaned up by LLE or SPE [5], and then analyzed for total estrogens.…”

“…Therefore, determining the contribution of each conjugated metabolite for accurate risk assessment is of considerable importance [10,[16][17][18].…”

“…Recently, Tso and Aga [10] developed an original procedure for the contemporaneous extraction and determination of the free and intact conjugated forms of the estrogens in milk by extracting deproteinized samples with two SPE cartridges used in tandem, followed by reversed-phase (RP) LC separation in alkaline conditions and negative electrospray ionization (ESI)-MS/MS analysis.…”

“…The principal instrumental analytical methods employed for estrogen analysis comprise gas chromatography-mass spectrometry (GC-MS), after derivatization to thermally stable derivatives [1,5], and liquid chromatography with tandem mass spectrometry (LC-MS/MS), without derivatization or derivatized by dansyl chloride to improve sensitivity [1,2,10].…”

Development and characterization of a nanodendritic silver-based solid-phase extraction sorbent for selective enrichment of endocrine-disrupting chemicals in water and milk samples

“…Seventy-five percent of milk is produced from pregnant cows in the modern dairy industry. Therefore, the content of estrogens in commercial milk may have increased due to the illegal use of estrogens [12]. The control of their illegal use has become an important challenge that requires immediate residue analysis of these estrogens in animal-derived food as well as in environmental samples.…”