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Assessment of the complementarity of temperature and flow-rate for response normalisation of aerosol-based detectors
journal contribution
posted on 2023-05-18, 04:45 authored by Khandagale, MM, Emily HilderEmily Hilder, Robert ShellieRobert Shellie, Paul HaddadPaul HaddadThe solvent dependency of the detection response is a major limitation of corona-charged aerosol detection (C-CAD). The present study empirically investigates the utility of temperature and flow-rate gradients to overcome solvent gradient limitations of C-CAD. In preliminary flow-injection investigations, it is demonstrated that the response of C-CAD remains relatively unaltered with variations in flow-rate when used with water-rich eluents. Based on these findings two separation approaches were developed and their utility for C-CAD response normalisation was demonstrated using a mixture of eight analytes. In the first approach the use of a solvent gradient is replaced with a temperature gradient performed under isocratic mobile phase conditions. Detection response is further enhanced by mixing a secondary stream of pure acetonitrile with the column effluent, yielding a 3-fold increase in detection response. In the second approach, flow-rate programming is used to improve speed of isocratic-temperature gradient separation. The use of simultaneous variation in flow-rate and column temperature reduced the separation time by 30%, with relatively uniform analyte response. Lastly, an inverse-gradient solvent compensation approach was used to evaluate the response homogeneity and the applicability of the above approaches for quantitative analysis. Good peak area reproducibility (RSD% < 15%) and linearity (R2 > 0.994, on a log-scale) over the sample mass range of 0.1-10μg was achieved. The response deviation across the mixture of eight compounds at seven concentration levels was 6-13% compared to 21-39% when a conventional solvent gradient was applied and this response deviation was comparable to that obtained in the inverse gradient solvent compensation approach. Finally, applicability of these approaches for typical pharmaceutical impurity profiling was demonstrated at a concentration of 5μg/mL (0.1% of the principal compound).
History
Publication title
Journal of Chromatography AVolume
1356Pagination
180-187ISSN
0021-9673Department/School
School of Natural SciencesPublisher
Elsevier Science BvPlace of publication
PO Box 211, Amsterdam, Netherlands, 1000 AeRights statement
Copyright 2014 ElsevierRepository Status
- Restricted