Surface-Assisted Laser Desorption Ionisation Time-Of-Flight Mass Spectrometry with an Activated Carbon Surface for the Rapid Detection of Underivatised Steroids

This article reports the rapid detection of 10 underivatised steroids using surface-assisted laser desorption ionisation time-of-flight mass spectrometry (SALDI TOF-MS). Numerous carbon surfaces were investigated as possible substrates to promote underivatised steroid desorption and ionisation and compared to established matrix assisted laser desorption ionisation (MALDI) approaches. The inexpensive and readily accessible surface of activated carbon allowed detection of all 10 steroids of interest; estrone, β-estradiol, estriol, 17α-ethynylestradiol, progesterone, pregnenolone, 17α-hydroxy progesterone, corticosterone, cortisone and hydrocortisone with on plate limits of detection ranging from 1.57 to 18.1. ng. The activated carbon surface produced minimal background interference, simple mass spectral interpretation and significantly improved analyte distribution when compared to a more conventional MALDI approach.