Collisional damping affects the relationship between ion mass and effective cyclotron frequency in Fourier transform mass spectrometry. The exact mass calibration equation（m/z=A/f＋（mneutral/m^^＋mneut...Collisional damping affects the relationship between ion mass and effective cyclotron frequency in Fourier transform mass spectrometry. The exact mass calibration equation（m/z=A/f＋（mneutral/m^^＋mneutral）k＋B/f（f＋（mneutral/m^^＋mneutralk））was therefore derived from the characteristic equation of system model, force=m（dv/dt）=qE-qv×B0-ξv,a frictional damping force）, in which k is amended by the shift of observed frequency of matrix ion or other known ion in external calibration. The mass obtained by the amended calibration equation is therefore immune to collisional damping and space-charge effects on mass accuracy. The relative errors of ion mass measured were all less than 2×10^-6.展开更多
The tapered element oscillating microbalance with filter dynamics measurement system （TEOM-FDMS） is an instrument commonly employed by the French air quality monitoring network. This instrument is currently calibrat...The tapered element oscillating microbalance with filter dynamics measurement system （TEOM-FDMS） is an instrument commonly employed by the French air quality monitoring network. This instrument is currently calibrated with calibration weights traceable to SI but having value and mass differences between each of them that are not representative of real atmospheric particle mass measurements. Moreover, these calibration weights do not allow detection of any technical problems associated with either the TEOM-FDMS sampling system upstream of the mass measurement or the intrinsic TEOM-FDMS filtration system. Therefore, a calibration method was developed using a portable reference aerosol generator （PRAG） that produces known and stable particle mass concentrations over time. Here, we present the characterization of the PRAG system in terms of a reference range of particle masses between 30 - 10 and 3456 ± 83 μg at three sampling times. Its coupling with the TEOM-FDMS and a global comparison between the defined reference range of particle masses and the measured masses obtained with each TEOM-FDMS implicated in this study are also presented.展开更多
文摘Collisional damping affects the relationship between ion mass and effective cyclotron frequency in Fourier transform mass spectrometry. The exact mass calibration equation（m/z=A/f＋（mneutral/m^^＋mneutral）k＋B/f（f＋（mneutral/m^^＋mneutralk））was therefore derived from the characteristic equation of system model, force=m（dv/dt）=qE-qv×B0-ξv,a frictional damping force）, in which k is amended by the shift of observed frequency of matrix ion or other known ion in external calibration. The mass obtained by the amended calibration equation is therefore immune to collisional damping and space-charge effects on mass accuracy. The relative errors of ion mass measured were all less than 2×10^-6.
文摘The tapered element oscillating microbalance with filter dynamics measurement system （TEOM-FDMS） is an instrument commonly employed by the French air quality monitoring network. This instrument is currently calibrated with calibration weights traceable to SI but having value and mass differences between each of them that are not representative of real atmospheric particle mass measurements. Moreover, these calibration weights do not allow detection of any technical problems associated with either the TEOM-FDMS sampling system upstream of the mass measurement or the intrinsic TEOM-FDMS filtration system. Therefore, a calibration method was developed using a portable reference aerosol generator （PRAG） that produces known and stable particle mass concentrations over time. Here, we present the characterization of the PRAG system in terms of a reference range of particle masses between 30 - 10 and 3456 ± 83 μg at three sampling times. Its coupling with the TEOM-FDMS and a global comparison between the defined reference range of particle masses and the measured masses obtained with each TEOM-FDMS implicated in this study are also presented.
