TY - JOUR
T1 - Double cation adduction in matrix-assisted laser desorption/ionization time-of-flight mass spectrometry of electron deficient anthraquinone derivatives
AU - Lou, X.W.
AU - Sinkeldam, R.W.
AU - Houts, van, W.H.
AU - Nicolas, Y.A.G.
AU - Janssen, P.G.A.
AU - Dongen, van, J.L.J.
AU - Vekemans, J.A.J.M.
AU - Meijer, E.W.
PY - 2007
Y1 - 2007
N2 - Six anthraquinone derivatives were analyzed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI TOF MS). Clear (pseudo) molecular ions were observed for all the compounds. Interestingly, for some derivatives, strong ions with double cation adduction were also recorded in the positive mode. It is remarkable that all these ions are singly charged. In this work, possible mechanisms for the double cation adduction were investigated and discussed. It appears that the double cation adduction was due to the electron deficient nature of the derivatives, and formed by taking up two singly charged cations and one electron. Substituents on the anthraquinone ring were found to have a significant effect on the double cation adduction. In contrast, no considerable influence of the acidity of MALDI matrix/solution was observed, even on the double proton adduction. Furthermore, it was demonstrated that double cation adduction might occur in the MALDI gas-phase plume. In addition to the anthraquinones, three more electron deficient compounds of different types, i.e. a perylene bisimide derivative (PB), 3,7-decanoylamino-4,8-dihydrobenzo[1,2-b:4,5-b]dithiophene-4,8-dione (TQ) and 6,6-phenyl C61-butyric acid methyl ester (PCBM), were also analyzed with MALDI TOF MS. The results indicate that the abnormal double cation adduction might be a normal phenomenon in the MALDI TOF MS analysis of many electron deficient compounds.
AB - Six anthraquinone derivatives were analyzed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI TOF MS). Clear (pseudo) molecular ions were observed for all the compounds. Interestingly, for some derivatives, strong ions with double cation adduction were also recorded in the positive mode. It is remarkable that all these ions are singly charged. In this work, possible mechanisms for the double cation adduction were investigated and discussed. It appears that the double cation adduction was due to the electron deficient nature of the derivatives, and formed by taking up two singly charged cations and one electron. Substituents on the anthraquinone ring were found to have a significant effect on the double cation adduction. In contrast, no considerable influence of the acidity of MALDI matrix/solution was observed, even on the double proton adduction. Furthermore, it was demonstrated that double cation adduction might occur in the MALDI gas-phase plume. In addition to the anthraquinones, three more electron deficient compounds of different types, i.e. a perylene bisimide derivative (PB), 3,7-decanoylamino-4,8-dihydrobenzo[1,2-b:4,5-b]dithiophene-4,8-dione (TQ) and 6,6-phenyl C61-butyric acid methyl ester (PCBM), were also analyzed with MALDI TOF MS. The results indicate that the abnormal double cation adduction might be a normal phenomenon in the MALDI TOF MS analysis of many electron deficient compounds.
U2 - 10.1002/jms.1161
DO - 10.1002/jms.1161
M3 - Article
C2 - 17200982
SN - 1076-5174
VL - 42
SP - 293
EP - 303
JO - Journal of Mass Spectrometry
JF - Journal of Mass Spectrometry
IS - 3
ER -