Fig 1.
Chromatogram of SIFT-MS concentration (ppbv) response to acetone and MTBE from aliquots of PGAB solution released in the glove chamber versus time.
The labels indicate background regions and aliquot volumes released.
Fig 2.
Calibration curves showing the linear fit of mean instrumental response for MTBE (dashed) and acetone (solid) versus liquid aliquot volumes injected into the chamber.
The uncertainty (error bars) was representative of the standard error of the mean for the measurement region after the instrument response had stabilized from release of a calibration aliquot.
Fig 3.
Linear fitting (dashed) of six replicates of upper range and lower range (inset) calibration data showing ΔB response versus liquid aliquot volume from calibrations.
The aggregated calibration data from replicates of calibration procedures were representative of the variability encountered with the SIFT-MS measurements done over multiple days.
Table 1.
Calibration curve values for the liquid and headspace response curves.
Fig 4.
Mean ratio of A/B versus volume of liquid (upper solid line) and headspace (lower solid line) for aliquots of various volumes (dots).
A mean ratio plus/minus the standard deviation (dashed lines), were considered purely liquid or headspace leaks. While a ratio of A/B (e.g. 0.6) between standard deviations, indicates a leak consisting of a mixture of liquid and headspace.
Fig 5.
Theoretical relationship between ratio A/B, the magnitude of the ppbv response, and the volumes of mixed leaks of liquid and headspace derived through equations 1 through 6.
Given 100 ppbv ΔBT and varying the amount of ΔAT to make ratios across the range of A/B, plotted versus the volume (circles) of headspace and liquid leaks with standard deviation (error bars).
Fig 6.
The relative error versus the ratio A/B for calculated volumes of mixed liquid and headspace leaks.
The standard deviation of instrumental measurements was propagated through the equations used to calculate liquid and headspace volumes from the magnitude and the ratio of the instrumental responses.
Table 2.
Propagated relative percent uncertainty in the calculation of leak volumes at significant ratios of A/B.
Fig 7.
Instrument response to acetone and MTBE, measured while using an air-cleaning type CSTD to transfer PGAB solution between two vials.
The changes in response in regions (a through d) represent activities at various time points, background collection, attaching vial adaptors, and transferring solution. The decline in signal to near baseline after region (d) was due to opening the chamber post experiment.
Fig 8.
Instrument response to acetone and MTBE, measured while using a barrier type CSTD to transfer PGAB solution between two vials.
The regions (a through d) represent various time points, which were correlated with activities during the solution transfer process. The decline in signal after region (d) was due to opening the chamber post experiment.
Fig 9.
Instrument response to acetone and MTBE, measured while using a second, barrier type, CSTD to transfer PGAB solution between two vials.
The regions (a through e) represent various time points, which were correlated with activities during the solution transfer process.