(EN) This document relates to materials and methods for identifying and/or quantifying immunoglobulins from a biological sample without pre-purification of the immunoglobulins prior to ionization and detection using mass spectrometry. For example, a monoclonal light chain from a monoclonal immunoglobulin may be observed using matrix assisted laser desorption ionization - time of flight (MALDI-TOF) mass spectrometry after diluting a sample containing the monoclonal immunoglobulin with an aqueous buffer containing acid and a reducing agent then mixing the sample with alpha- cyano-4-hydroxycinnamic acid matrix (CHCA). In another example, an intact monoclonal immunoglobulin may be observed in a sample using MALDI-TOF mass spectrometry after diluting the sample containing the monoclonal immunoglobulin with water then mixing the sample with CHCA matrix.