Detection and quantification of metastable photoproducts of trenbolone and altrenogest using liquid chromatography–tandem mass spectrometry

Abstract

Here, we developed a novel and sensitive method for the detection and quantification of metastable trenbolone and altrenogest photoproducts in agricultural receiving waters based on solid phase extraction (SPE) and liquid chromatography-tandem mass spectrometry (LC–MS/MS). Primary method analytes were seven cycloaddition or photohydration transformation products of 17α-trenbolone (17α-TBOH), 17β-trenbolone (17β-TBOH), trendione (TBO), and altrenogest (ALT), which are key contributors to the fate and environmental risks of these steroidal pharmaceuticals. Because commercial analytical standards are not available, reference standards for photoproducts were generated from trenbolone or ALT with a solar simulator (˜6 h, >10 half-lives). Efficient detection of metastable photoproducts required cold and pH neutral conditions, rapid sample processing, minimal sample storage, and consideration of cationic artifacts. Method detection limits (MDLs) were 0.034-0.40 ng L−1 for parent compounds and 0.16–2.1 ng L−1 for photoproducts, sufficient for their detection in agroecosystems. Matrix suppression was observed and corrected by internal standards, and relative recovery rates were near 100% for all analytes except for 12-OH-17α-TBOH (˜75% recovery). Intra-day variation was <20% and inter-day variation <25% for all the analytes. The developed method is capable of the analysis of trenbolone, altrenogest, and their key bioactive photoproducts in agricultural receiving waters.