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Assessment of Multivariate Chemometric Methods Combined with Comprehensive Two-dimensional Gas Chromatography Towards Determination of Aromatic Compounds in Complex Samples
, M.Sc. Thesis Sharif University of Technology ; Parastar Shahri, Hadi (Supervisor)
Abstract
In recent years, comprehensive two-dimensional gas chromatography (GC×GC) have emerged as a powerful technique suitable for the separation of complex mixtures because of their higher resolution and higher peak capacity. The invention of GC×GC is a milestone development in chromatographic history. However, one of the main challenges in chromatography and especially in GC×GC is related to the difficulty on the analysis and interpretation of the enormous amount of data obtained in these cases. In this context, resolution, identification and quantification of target compounds in the presence of interferences are issues which have a great importance and not totally solved yet. The present...
Second-order calibration for simultaneous determination of pharmaceuticals in water samples by solid-phase extraction and fast high-performance liquid chromatography with diode array detector
, Article Chemometrics and Intelligent Laboratory Systems ; Vol. 137, issue , 2014 , pp. 146-154 ; ISSN: 01697439 ; Parastar, H ; Sharif University of Technology
Abstract
A fast high-performance liquid chromatography-diode array detection (HPLC-DAD) approach combined to solid phase extraction (SPE) as a pre-concentration step is developed for simultaneous determination of five selected pharmaceuticals (carbamazepine, naproxen, diclofenac, gemfibrozil and mefenamic acid) in water samples. The effective factors on the efficiency of SPE procedure are optimized using faced-centered central composite design (FCCD). In addition, multi-response optimization by using Derringer's desirability function is used to find the optimum experimental conditions for extraction of analytes from well and river waters. Due to the complexity of water matrices and the presence of...
A systematic study on the effect of noise and shift on multivariate figures of merit of second-order calibration algorithms
, Article Analytica Chimica Acta ; Volume 952 , 2017 , Pages 18-31 ; 00032670 (ISSN) ; Parastar, H ; Sereshti, H ; Olivieri, A ; Tauler, R ; Sharif University of Technology
Elsevier B.V
2017
Abstract
In the present study, multivariate analytical figures of merit (AFOM) for three well-known second-order calibration algorithms, parallel factor analysis (PARAFAC), PARAFAC2 and multivariate curve resolution-alternating least squares (MCR-ALS), were investigated in simulated hyphenated chromatographic systems including different artifacts (e.g., noise and peak shifts). Different two- and three-component systems with interferences were simulated. Resolved profiles from the target components were used to build calibration curves and to calculate the multivariate AFOMs, sensitivity (SEN), analytical sensitivity (γ), selectivity (SEL) and limit of detection (LOD). The obtained AFOMs for different...
Resolution and quantification of complex mixtures of polycyclic aromatic hydrocarbons in heavy fuel oil sample by means of GC × GC-TOFMS combined to multivariate curve resolution
, Article Analytical Chemistry ; Volume 83, Issue 24 , 2011 , Pages 9289-9297 ; 00032700 (ISSN) ; Radović, J. R ; Jalali-Heravi, M ; Diez, S ; Bayona, J. M ; Tauler, R ; Sharif University of Technology
Abstract
Comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GC × GC-TOFMS) combined to multivariate curve resolution-alternating least-squares (MCR-ALS) is proposed for the resolution and quantification of very complex mixtures of compounds such as polycyclic aromatic hydrocarbons (PAHs) in heavy fuel oil (HFO). Different GC × GC-TOFMS data slices acquired during the analysis of HFO samples and PAH standards were simultaneously analyzed using the MCR-ALS method to resolve the pure component elution profiles in the two chromatographic dimensions as well as their pure mass spectra. Outstandingly, retention time shifts within and between GC × GC runs were not affecting...