Evaluation of a pulsed glow discharge time-of-flight mass spectrometer as a detector for gas chromatography and the influence of the glow discharge source parameters on the information volume in chemical speciation analysis

Abstract

The figures of merit of a pulsed glow discharge time-of-flight mass spectrometer (GD-TOFMS) as a detector for gas chromatography (GC) analysis were evaluated. The mass resolution for the GD-TOFMS was determined on FWHM in the high mass range (208Pb+) as high as 5,500. Precision of 400 subsequent analyses was calculated on 63Cu+ to be better than 1% RSD with no significant drift over the time of the analysis. Isotope precision based on the 63Cu+/65Cu+ ratio over 400 analyses was 1.5% RSD. The limits of detection for gaseous analytes (toluene in methanol as solvent) were determined to be as low as several hundred ppb or several hundred pg absolute without using any pre-concentration technique. Furthermore, the different GD source parameters like capillary distance, cathode-anode spacing, and GD source pressure with regards to the accessible elemental, structural, and molecular information were evaluated. It was demonstrated that each of these parameters has severe influence on the ratio of elemental, structural, and parent molecular information in chemical speciation analysis.

A comparison of non-pulsed radiofrequency and pulsed radiofrequency glow discharge orthogonal time-of-flight mass spectrometry for analytical purposes

“…As can be seen, the isotopic ratios measured using the pulsed mode show higher accuracy than those obtained using the non-pulsed radiofrequency mode and thus indicating lower polyatomic interferences. For example, the isotopic ratio 12 C + / 13 C + is deviated 7% from the theoretical value using the pulsed RF mode, while it derivates 87% using the non-pulsed RF mode (due to the presence of 12 Cr + signal in non-pulsed RF mode. However, in pulsed mode RF this chromium interference can be avoided by selecting an appropriate time window in the afterglow.…”

Tunable fragmentation of organic molecules in laser ablation glow discharge time-of-flight mass spectrometry

“…In another report by Lewis et al [18], the successful analysis of aromatic compounds such as o-xylene using a pulsed GD-TOFMS coupled to gas chromatography (Ar as the carrier) was reported. A pulsed GD coupled to a gas chromatography system was also reported by Fliegel et al [19], where elemental and molecular information from gaseous analytes such as toluene in methanol as solvent was demonstrated. In addition, Majidi et al [16] showed the possibility of performing the chemical speciation of volatile compounds using a μs-pulsed GD-TOF system.…”

Electrodeposition of Metal Matrix Nanocomposites: Improvement of the Chemical Characterization Techniques

“…However, in average the sputtering rate is much lower and so pulsed GDs offer a great potential for ultra-thin layers. Moreover, different discharge processes take place at different times within a single pulse and this allows, when coupled to a mass analyser with a time resolved signal acquisition spectrometer such as the TOF (time of flight), to obtaining quasi-simultaneous structural, molecular and elemental information from the sample (Fliegel et al, 2006). It is known that emission and ionization yields are also affected by small amounts of hydrogen (Weyler & Bengtson, 2010) and, in general, by light elements (C, N and O) in the plasma, coming either from contamination of the plasma gas (Ar) or from the specimen sputtering (i.e.…”