This study established a solid-phase extraction-ultrahigh performance liquid chromatography-triple quadrupole tandem mass spectrometry (SPE-LC-ESI-MS) method for the determination of naturally occurring prostaglandins (dinoprost) and their synthetic analogs (cloprostenol) in milk.The method was then validated to investigate the effects of 5 processing techniques (ultra-high temperature sterilization, spray drying, pasteurization, skimming, and freezing) on the stability of added hormones in raw milk.The results showed that the limit of detection of this method was 0.04-0.12ng/mL in the concentration range of 0-100 ng/mL, and the limit of quantitation was 0.11-0.37ng/mL, with good linearity (R 2 > 0.99).The processing results indicated that the recoveries after spray drying and ultra-high temperature sterilization were both below 10%, which may be related to the properties of prostaglandins themselves.Furthermore, the effect of freezing on the residual rates of the 2 prostaglandins was almost negligible.
Lu et al. (Mon,) studied this question.