scholarly journals On-line SPME derivatization for the sensitive determination of multi-oxygenated volatile compounds in air

2021 ◽  
Author(s):  
Esther Borrás ◽  
Luis A. Tortajada-Genaro ◽  
Milagros Ródenas ◽  
Teresa Vera ◽  
Thomas Speak ◽  
...  
Keyword(s):  
Good Accuracy ◽  
Accurate Determination ◽  
Automated System ◽  
Oxygenated Volatile Organic Compounds ◽  
Volatile Organic ◽  
On Line ◽  
Sensitive Determination ◽  
Secondary Aerosols ◽  
Hydroxy Aldehydes

Abstract. Multi-oxygenated volatile organic compounds are important markers of air pollution and precursors of ozone and secondary aerosols in both polluted and remote environments. Herein, their accurate determination was enhanced. The approach was based on an automated system for active sampling and on-fiber derivatization coupled with GC-MS technique. The method capability was determined for different compound families, such as aldehydes, ketones, α-dicarbonyls, hydroxy-aldehydes, hydroxy-ketones and, carboxylic acids. A good accuracy (

scholarly journals On-line solid phase microextraction derivatization for the sensitive determination of multi-oxygenated volatile compounds in air

2021 ◽  
Vol 14 (7) ◽  
pp. 4989-4999
Author(s):  
Esther Borrás ◽  
Luis A. Tortajada-Genaro ◽  
Milagro Ródenas ◽  
Teresa Vera ◽  
Thomas Speak ◽  
...  
Keyword(s):  
Solid Phase ◽  
Accurate Determination ◽  
High Volume ◽  
Automated System ◽  
Gas Chromatography Mass Spectrometry ◽  
Oxygenated Compounds ◽  
On Line ◽  
Secondary Aerosols ◽  
Hydroxy Aldehydes

Abstract. Multi-oxygenated volatile organic compounds are important markers of air pollution and precursors of ozone and secondary aerosols in both polluted and remote environments. Herein, their accurate determination was enhanced. The approach was based on an automated system for active sampling and on-fibre derivatization coupled with the gas chromatography–mass spectrometry (GC–MS) technique. The method capability was determined for different compound families, such as aldehydes, ketones, α-dicarbonyls, hydroxy-aldehydes, hydroxy-ketones, and carboxylic acids. A good accuracy (<7 %) was demonstrated from the results compared to Fourier-transform infrared spectroscopy (FTIR). Limits of detection (LODs) of 6–100 pptV were achieved with a time resolution lower than 20 min. The developed method was successfully applied to the determination of multi-oxygenated compounds in air samples collected during an intercomparison campaign (EUROCHAMP-2020 project). Also, its capability and accuracy for atmospheric monitoring was demonstrated in an isoprene ozonolysis experiment. Both were carried out in the high-volume outdoor atmospheric simulation chambers (EUPHORE, 200 m3). In summary, our developed technique offers near-real-time monitoring with direct sampling, which is an advantage in terms of handling and labour time for a proper quantification of trace levels of atmospheric multi-oxygenated compounds.

Fast calibration of CBED patterns for quantitative analysis

1993 ◽  
Vol 51 ◽  
pp. 674-675
Author(s):  
M.A. Gribelyuk ◽  
M. Rühle
Keyword(s):  
Reciprocal Lattice ◽  
Accurate Determination ◽  
Incident Beam ◽  
Crystal Thickness ◽  
Structure Model ◽  
Beam Direction ◽  
Transmitted Beam ◽  
Reciprocal Vector ◽  
On Line

A new method is suggested for the accurate determination of the incident beam direction K, crystal thickness t and the coordinates of the basic reciprocal lattice vectors V1 and V2 (Fig. 1) of the ZOLZ plans in pixels of the digitized 2-D CBED pattern. For a given structure model and some estimated values Vest and Kest of some point O in the CBED pattern a set of line scans AkBk is chosen so that all the scans are located within CBED disks.The points on line scans AkBk are conjugate to those on A0B0 since they are shifted by the reciprocal vector gk with respect to each other. As many conjugate scans are considered as CBED disks fall into the energy filtered region of the experimental pattern. Electron intensities of the transmitted beam I0 and diffracted beams Igk for all points on conjugate scans are found as a function of crystal thickness t on the basis of the full dynamical calculation.

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