We are getting a strong and persistent negative ion adduct of 100 Da in electrospray. We are working with a small molecule (syringic acid). Does anyone have advice as to the nature and possible origin of the adducting agent? Any and all advice will be appreciated Kym and Gazi Kym Francis Faull, Ph.D. Director, Pasarow Mass Spectrometry Laboratory Jane and Terry Semel Institute for Neuroscience and Human Behavior at UCLA Professor Emeritus on Recall, Department of Psychiatry and Biobehavioral Sciences David Geffen School of Medicine at UCLA Telephone: (310) 206 7881 (office) Telephone: (310) 206 7886 (laboratory) Facsimile: (310) 206 2161 Electronic mail: <email obscured> <email obscured>>