A preconcentrator coupled to a GC/FTMS: Advantages of self-chemical ionization, mass measurement accuracy, and high mass resolving power for GC applications

Bimolecular and unimolecular contributions to the disparate self-chemical ionizations of α-Pinene and camphene isomers

“…Experimental results showed that the camphene system was more reactive than ␣-pinene ensemble toward ␣ SCI; this is consistent with our previous GC/FT-ICR MS results on SCI based differentiation of ␣-pinene and ␣ camphene [1]. At short reaction delays (t Ͻ15 s), the ␣-pinene SCI mass spectra showed higher abundance of ␣ association ion-molecule product ions (at m/z 217 and 273) than camphene.…”

“…The previous GC/FT-ICR MS studies were performed at 24 eV electron energy to eliminate ionization of the helium carrier gas [1]. Hence, we used the same 24 eV ionization energy for the bulk of the studies described herein.…”

“…Conversely, under similar experimental conditions, the ␣-pinene molecular ions as well as the major fragment ions of ␣ ␣-pinene and ␣ camphene showed no unimolecular dissociation. The ␣-pinene and camphene molecular ions reviously, we used a pre-concentrator gas chromatography Fourier transform ion cyclotron resonance PC/GC/FT-ICR) mass spectrometer for headspace analysis of detached pine twigs [1]. It was observed that the GC eluted camphene (C 10 H 16 ) underwent SCI whereas the other terpene isomers (C 10 H 16 ) did not show any significant SCI products.…”

“…Series of experiments were designed to answer the following questions: (1) What are the key chemical processes that give rise to different SCI patterns for ␣-pinene and camphene isomers? (2) Can we use our ␣ experimental findings and construct a simple kinetic model to predict SCI mass spectral patterns as a function of time and pressure?…”

“…Hence, to answer the aforementioned questions (1) and (2), we investigated the SCI contributions from terpene molecular ions and various major fragment ions. Results from three research areas that include i-unimolecular dissociation of parent and fragment ions, ii-reactivities of major fragment ions, and iii-PA of ␣-pinene and camphene, are reported.…”