Application of dicyandiamide as a matrix additive in fast atom bombardment mass spectrometry

Dicyandiamide (DCDA) is used as a chemical additive in the fast atom bombardment (FAB) matrix 3‐mercaptopropane‐l,2‐diol (thioglycerol) and propane‐l,2,3‐triol (glycerol). It is demonstrated that DCDA can be used to generate adduct ions [M + H + DCDA]+ for a variety of common organic functional groups to confirm the molecular ion [M + H]+. It is particularly useful for aromatic and alkyl amines and these compounds were therefore investigated in greater detail. Primary and secondary amines on heating react with DCDA to produce biguanides. DCDA can be used as a derivatizing reagent, but the reaction times are typically longer than 12 h and, therefore, it has limited utility. Biguanides can be detected at the nanogram level in full‐range FAB mass spectral analysis.