A RAPID APPROACH FOR THE DETECTION OF DIPICOLINIC ACID IN BACTERIAL-SPORES USING PYROLYSIS MASS-SPECTROMETRY

Curie-point pyrolysis/triple quadrupole mass spectrometry and micro-tu be furnace pyrolysis/quadrupole ion trap mass spectrometry have been u sed to detect dipicolinic acid (DPA) in sporulated whole bacteria, DPA in whole cells of sporulated Bacillus anthracis reacted in situ durin g pyrolysis with tetramethylammonium hydroxide to form the dimethyl es ter derivative of DPA, dimethyl-2,6-dipicolinate (mDPA), The mDPA was identified by its positive-ion electron ionization fragmentation patte rn and confirmed with tandem mass spectrometry, In an oxidative pyroly sis/quadrupole ion trap instrument, the mDPA mass spectrum showed char acteristic positive-ion electron ionization fragmentation along with a significant [M + 1](+) ion due to self-chemical ionization. The chara cteristic collision-induced dissociation fragments of mDPA were used t o establish the presence of sporulation in B. anthracis whole cells at a concentration of 2.2 x 10(7) CFU (colony-forming units)/mL using th e triple quadrupole instrument, The total time for analysis, including sample preparation, was less than 10 minutes for both instruments.