KB001929: Can an ESI Source be Used for Multiple Charged Molecules? - General LC/MS 

Yes , Large molecules often acquire more than one charge. Electrospray is very useful for analyzing large biomolecules like proteins , peptides , oligonucleotides etc., as well as small molecules like benzodiazepine and sulfated conjugates.
ESI can analyze molecules as large as 150,000 u (daltons) even though the range of MS may be few thousands. When such large molecules acquire multiple charges using deconvolution process (mathematical algorithm) we can arrive at the actual weight of the analyte.