Rapid screening of testosterone in the aquatic environment using direct analysis in real-time (DART) mass spectrometry

Testosterone (TES) in the aquatic environment was analyzed for the first time using direct analysis in real-time mass spectrometry (DART MS) without any sample pre-treatment. TES with the addition of 2H and its dehydration products was observed. The instrument parameters were studied systematically and optimized concerning the specific analyte. Limits of detection for the pure compound were 2.5 ng for TES spiked in raw wastewater samples and 500 pg in TES standards. The whole analysis time was within 1 min. A simple derivatization of TES by hydroxylamine and introducing ammonia as dopant gas for the sensitivity and intensity enhancement were also investigated. Both methods improved the intensity of the TES signal by about twofold. The results of this study illustrate that DART MS is capable to detect TES in complicated matrixes and could realize the rapid and direct screening of TES in the aquatic environment at a low nanogram range for pure compound without coupling with any pre-treatment tools.