regular expression Regular expression for adduct ion formula ([[:digit:]{0,1}M([+][:digit:]{0,1}(H|K|(Na)|(Li)|(Cl)|(Br)|(NH3)|(NH4)|(CH3OH)|(IsoProp)|(DMSO)|(FA)|(Hac)|(TFA)|(NaCOOH)|(HCOOH)|(CF3COOH)|(ACN))){0,}([-][:digit:]{0,1}(H|(H2O)|(CH2)|(CH4)|(NH3)|(CO)|(CO2)|(COCH2)|(HCOOH)|(C2H4)|(C4H8)|(C3H2O3)|(C5H8O4)|(C6H10O4)|(C6H10O5)|(C6H8O6))){0,}][:digit:]{0,1}[+-]). MS MS:1002812