The influence of hydrostatic pressure on gas diffusion in polymer and nano-composite membranes: Application to membrane inlet mass spectrometry

Calibration of membrane inlet mass spectrometric measurements of dissolved gases: Differences in the responses of polymer and nano-composite membranes to variations in ionic strength

“…Thus the permeability properties of the PDMS membrane are influenced by hydrostatic pressure in a manner that presents substantial challenges to quantitative calibration. In contrast, the transmission properties of the PNC membranes constructed by Miranda et al [16] demonstrated little if any response to changes in hydrostatic pressure.…”

“…Synthesis and characterization of polysiloxane nano-composite (PNC) membranes are described in Miranda et al [16]. An overview of the process is given as follows: an anodic aluminum oxide (AAO) membrane was mounted on a stainless steel frit and secured on a membrane module with vacuum epoxy.…”

“…Mass spectrometry measurements were conducted using an experimental configuration similar to that described in Miranda et al [16]. The PNC and PDMS membrane modules were connected individually to a quadrupole mass spectrometer (Inficon, Transpector 2.0 Gas Analyzer System) via a Swagelok fitting.…”

“…The baseline gas had CH 4 , Ar and CO 2 at lower parts-per-billion levels, well below the detection limits of our mass spectrometer. In the case of N 2 , baselines were measured prior to each experimental run by degassing the solution at sample flow rate equal to zero [16]. Sufficient time was allowed for the sample to be thoroughly degased at the membrane interface.…”

“…At higher hydrostatic pressures, conventional PDMS membranes have been reported to demonstrate variable permeability properties [14,15]. Miranda et al [16] recently described the gas transmission characteristics of polysiloxane nano-composite (PNC) membranes that were coupled to the inlet system of a mass spectrometer. The gas transmission properties of PNC membranes were compared to those of a conventional PDMS membrane over a range of hydrostatic pressures.…”