In the field of doping control, pretreatment for urine sample for HPLC-MS detection is time consuming and tedious. To avoid that, we combined reactive desorption electrospray ionization (reactive DESI) and tandem mass spectrometry, spray solutions containing hydroxylamine allow heterogeneous reactions of hydroxylamine with steroids during the ionization process.

For example, three different sterois were added in raw urine sample and then the urine were simply dried on the glass slide for analysis. While comparing the Reactive DESI spectrum (lower) and DESI spectrum (upper), reaction products of these steroids were greatly enhanced. These peaks can be identified with further tandem mass spectrometry for confirmation.

Huang GM, Chen H, Zhang XR, Cooks RG, Ouyang Z, Analytical Chemistry , 2007 , 79(21), 8327-8332