A novel ionic liquid 3-(2-hydrazinyl-2-oxoethyl)-1-methyl-1H-imidazol-3-ium chloride as a derivatization reagent for HPLC-HRMS determination of steroid hormones in urine

This work demonstrates for the first time the possibility of using a novel ionic liquid 3-(2-hydrazinyl-2-oxoethyl)-1-methyl-1H-imidazol-3-ium chloride ([HOMI]Cl) as a derivatization reagent for steroid hormones and their subsequent analysis using ultra-high performance liquid chromatography–quadrupole time-of-flight mass spectrometry in human urine. Derivatization conditions, such as pH, reagent concentration, reaction time and temperature were evaluated and optimized. A comparative study of [HOMI]Cl and hydroxylamine effectiveness revealed a formation of both syn- and anti-forms of the steroid derivatives for the novel [HOMI]Cl reagent similarly to a derivatization with hydroxylamine. Hence obtained limits of quantitation were comparable to the literature values obtained with Girard P and hydroxylamine reagents (0.15 to 7.5 ng/mL). Finally, in-depth optimization of [HOMI]Cl hydrophobicity and ionization source conditions were found necessary to further improve the electrospray response of hence derivatized steroids.