Performance Evaluation of an EI&CI Dual Ionization TOFMS Hyphenated with a Flow Modulated GC×GC System.

The use and compatibility of a dual-ionization TOFMS operating an EI source and a CI source in parallel using a single TOF mass analyzer with flow modulated two-dimensional GC (GC×GC) is described. Important figures of merit of the mass spectrometer that are required for two-dimensional GC hyphenation such as acquisition speed, ion source response, EI/CI switching, the GC transfer, and data alignment are carefully investigated and addressed. Improved fast switching ion optics allow switching in a 100 Hz frequency between EI and CI spectra sampled from the same GC×GC effluent.

Evaluation of GC-EI&CI-TOFMS for Nontarget Analysis of Industrial Wastewater Using Hydrophilic-Lipophilic-Balanced SPME.

The evaluation of nontarget analysis (NTA) techniques for the monitoring of wastewater is important as wastewater is an anthropogenic pollution source for aquatic ecosystems and a threat to human and environmental health. This study presents the proof-of-concept NTA of industrial wastewater samples. A prototype hydrophilic-lipophilic-balanced (HLB) SPME and gas chromatography interfaced with time-of-flight high-resolution mass spectrometry (GC-TOFMS) with electron ionization (EI) and chemical ionization (CI) in parallel are employed.

Gas chromatography coupled to time-of-flight mass spectrometry using parallel electron and chemical ionization with permeation tube facilitated reagent ion control for material emission analysis.

Rationale: Volatile organic compounds (VOCs) emitted by an artificial leather part for car interiors are determined using GC-MS (gas chromatograph coupled to a mass spectrometer) using simultaneous electron and chemical ionization (EI&CI). A device for swift reagent ion switching in CI mode between consecutive runs is presented.

Methods: VOCs emitted from the investigated material were sampled onto Tenax® absorption tubes using micro emission chambers and subsequently injected into the GC through thermal desorption.

Evaluating residual compressive strength of post-fire concrete using Raman Spectroscopy.

Cement and water within the concrete mass create a hydrated phase which acts as the glue for holding the sand and coarse aggregates in place to develop a strong construction material. The most important phase within the cement matrix is that of calcium silicate hydrate (CSH), which is largely responsible for the concrete strength. Decomposition of the CSH phase due to high temperatures will affect compressive strength of the concrete.