Analysis of nucleoside-estrogen adducts by LC-ESI-MS-MS

Liquid chromatography coupled with tandem mass spectrometry (LC-MS-MS) has been used for the assessment of the reactivity of estradiol-2,3-quinone tow ards deoxyribonucleosides in crude reaction mixtures. The use of LC-MS-MS a llowed the direct injection of crude reaction mixtures, thus avoiding tedio us sample preparation and purification steps before the mass spectrometric analysis of the prepared adducts. Several original (sometimes minor) adduct s could be evidenced with deoxyguanosine and a new addition product has bee n characterized in the reaction of estradiol-2,3-quinone with deoxycytidine . Multisequential MSn mass spectrometry performed on a quadrupole ion-trap mass spectrometer enabled the discrimination of isomeric adducts present in crude reaction mixtures. These results show that LC-MS-MS is a very powerf ul analytical tool for the detection and characterization of adducts in cru de reaction mixtures.