1
|
Purcaro G, Stefanuto PH, Franchina FA, Beccaria M, Wieland-Alter WF, Wright PF, Hill JE. SPME-GC×GC-TOF MS fingerprint of virally-infected cell culture: Sample preparation optimization and data processing evaluation. Anal Chim Acta 2018; 1027:158-167. [PMID: 29866265 DOI: 10.1016/j.aca.2018.03.037] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 03/16/2018] [Accepted: 03/18/2018] [Indexed: 02/01/2023]
Abstract
Untargeted metabolomics study of volatile organic compounds produced by different cell cultures is a field that has gained increasing attention over the years. Solid-phase microextraction has been the sampling technique of choice for most of the applications mainly due to its simplicity to implement. However, a careful optimization of the analytical conditions is necessary to obtain the best performances, which are highly matrix-dependent. In this work, five different solid-phase microextraction fibers were compared for the analysis of the volatiles produced by cell culture infected with the human respiratory syncytial virus. A central composite design was applied to determine the best time-temperature combination to maximize the extraction efficiency and the salting-out effect was evaluated as well. The linearity of the optimized method, along with limits of detection and quantification and repeatability was assessed. Finally, the effect of i) different normalization techniques (i.e. z-score and probabilistic quotient normalization), ii) data transformation (i.e. in logarithmic scale), and iii) different feature selection algorithms (i.e. Fisher ratio and random forest) on the capability of discriminating between infected and not-infected cell culture was evaluated.
Collapse
Affiliation(s)
- Giorgia Purcaro
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, United States.
| | | | - Flavio A Franchina
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, United States
| | - Marco Beccaria
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, United States
| | | | - Peter F Wright
- Geisel School of Medicine, Dartmouth College, Hanover, NH, 03755, United States; Dartmouth-Hitchcock Medical Center, Lebanon, NH, 03756, United States
| | - Jane E Hill
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, United States; Geisel School of Medicine, Dartmouth College, Hanover, NH, 03755, United States
| |
Collapse
|
2
|
Brokl M, Bishop L, Wright CG, Liu C, McAdam K, Focant JF. Multivariate analysis of mainstream tobacco smoke particulate phase by headspace solid-phase micro extraction coupled with comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry. J Chromatogr A 2014; 1370:216-29. [PMID: 25454146 DOI: 10.1016/j.chroma.2014.10.057] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 10/16/2014] [Accepted: 10/18/2014] [Indexed: 11/24/2022]
Abstract
A method involving headspace solid-phase microextraction (HS-SPME) and comprehensive two-dimensional gas chromatography (GC×GC) coupled to time-of-flight mass spectrometry (TOFMS) was developed and applied to evaluate profiles of volatile compounds present in mainstream tobacco smoke particulate matter trapped on glass fiber filters. Six SPME fibers were tested for the extraction capacities toward selected compounds, showing the best results for the polyacrylate fiber. The optimization of the extraction conditions was carried out using multivariate response surface methodology. Two cigarette types differing in a filter design were analyzed using optimized conditions. A template was built in order to generate comprehensive chemical information, which conceded obtaining consistent information across 24 chromatograms. Principal component analysis (PCA) allowed a clear differentiation of the studied cigarette types. Fisher ratio analysis allowed identification of compounds responsible for the chemical differences between the cigarette samples. Of the selected 143 most important ones, 134 analytes were reduced by the active carbon filter, while for nine, classical cellulose acetate filter was more efficient.
Collapse
Affiliation(s)
- Michał Brokl
- CART - Chemistry Department, Organic & Biological Analytical Chemistry, University of Liège, Liège, Belgium
| | - Louise Bishop
- Group Research and Development, British American Tobacco, Regents Park Road, Southampton SO15 8TL, UK
| | - Christopher G Wright
- Group Research and Development, British American Tobacco, Regents Park Road, Southampton SO15 8TL, UK
| | - Chuan Liu
- Group Research and Development, British American Tobacco, Regents Park Road, Southampton SO15 8TL, UK
| | - Kevin McAdam
- Group Research and Development, British American Tobacco, Regents Park Road, Southampton SO15 8TL, UK
| | - Jean-François Focant
- CART - Chemistry Department, Organic & Biological Analytical Chemistry, University of Liège, Liège, Belgium.
| |
Collapse
|
3
|
Peroni D, Janssen HG. Comprehensive two-dimensional gas chromatography under high outlet pressure conditions: a new approach to correct the flow-mismatch issue in the two dimensions. J Chromatogr A 2014; 1332:57-63. [PMID: 24513348 DOI: 10.1016/j.chroma.2014.01.051] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 01/15/2014] [Accepted: 01/16/2014] [Indexed: 11/22/2022]
Abstract
The typical column sets employed in comprehensive two-dimensional gas chromatography (GC × GC) suffer from the impossibility to fully exploit the efficiency of both dimensions simultaneously. Adding a restrictor at the end of the second dimension is a possible approach to adjust the linear velocity profile. Under these high outlet pressure conditions the second dimension becomes much slower while the effect on the primary column is limited. The gap in terms of optimum inlet pressures is thus reduced. A program written in Microsoft Excel was used to calculate the efficiencies of the two dimensions in GC × GC at different outlet pressures. A GC × GC set-up with a restrictor at the end of the second dimension column was successfully installed. Experiments proved that this is a possible way to have a better exploitation of the columns. The chromatograms obtained for a number of applications confirm that the separations achieved at elevated outlet pressure are more efficient than those obtained with the same column set under atmospheric outlet conditions. The price to pay is that the separations become considerably slower.
Collapse
|