On-line detection and quantification of trace impurities in vaporisable samples by direct liquid introduction process mass spectrometry

Owen, Andrew W.; Nordon, Alison; Littlejohn, David; Lynch, Thomas P.; Lancaster, J. Steven; Wright, Robert G.

doi:10.1039/c4ay01064g

Cited by 2 publications

(2 citation statements)

References 14 publications

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“…The ion dwell time was set to 1 s ion -1 . The custom designed thermal vaporiser is shown in Figure 2 and has been described previously [39]. Glass lined tubing (SGE Analytical Science, UK) was wrapped around a metal block that was heated by a 350 W cartridge heater.…”

Section: On-line Mass Spectrometry With Thermal Vaporisermentioning

confidence: 99%

“…However, these methods are not ideal for continuous sampling; when a carrier gas is used to transport the sample vapours to the mass spectrometer variations in the carrier gas flow and inefficient mixing with the sample vapour can cause signal instability. In a previous study, a thermal vaporiser for direct liquid sampling mass spectrometry (DLSMS) was reported that can be used for continuous analysis of liquid streams [39]. Benzene, toluene and o-xylene in the range 0 -110 mg kg -1 were determined in ethanol and the vaporiser could be used to generate stable mass spectrometric responses for the analytes over several hours.…”

Section: Introductionmentioning

confidence: 99%

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Monitoring of an esterification reaction by on-line direct liquid sampling mass spectrometry and in-line mid infrared spectrometry with an attenuated total reflectance probe

Owen

McAulay

Nordon

et al. 2014

Analytica Chimica Acta

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A specially designed thermal vaporiser was used with a process mass spectrometer designed for gas analysis to monitor the esterification of butan-1-ol and acetic anhydride. The reaction was conducted at two scales: in a 150 mL flask and a 1L jacketed batch reactor, with liquid delivery flow rates to the vaporiser of 0.1 and 1.0 mLmin(-1), respectively. Mass spectrometry measurements were made at selected ion masses, and classical least squares multivariate linear regression was used to produce concentration profiles for the reactants, products and catalyst. The extent of reaction was obtained from the butyl acetate profile and found to be 83% and 76% at 40°C and 20°C, respectively, at the 1L scale. Reactions in the 1L reactor were also monitored by in-line mid-infrared (MIR) spectrometry; off-line gas chromatography (GC) was used as a reference technique when building partial least squares (PLS) multivariate calibration models for prediction of butyl acetate concentrations from the MIR spectra. In validation experiments, good agreement was achieved between the concentration of butyl acetate obtained from in-line MIR spectra and off-line GC. In the initial few minutes of the reaction the profiles for butyl acetate derived from on-line direct liquid sampling mass spectrometry (DLSMS) differed from those of in-line MIR spectrometry owing to the 2 min transfer time between the reactor and mass spectrometer. As the reaction proceeded, however, the difference between the concentration profiles became less noticeable. DLSMS had advantages over in-line MIR spectrometry as it was easier to generate concentration profiles for all the components in the reaction. Also, it was possible to detect the presence of a simulated impurity of ethanol (at levels of 2.6 and 9.1% mol/mol) in butan-1-ol, and the resulting production of ethyl acetate, by DLSMS, but not by in-line MIR spectrometry.

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Section: On-line Mass Spectrometry With Thermal Vaporisermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%