title: Chemometric optimization of derivatization reactions prior to gas chromatography-mass spectrometry analysis.
abstract: Derivatization is a methodological technique that can be used to make an organic compound more suitable for qualitative and/or quantitative analysis (e.g. pharmaceuticals). However, many analysts try to avoid this analytical procedure as it is time-consuming and labour-intensive. On the other hand, an inter-laboratory study demonstrated that with regard to sensitivity and measurement uncertainty, gas chromatography coupled to mass-spectrometry was superior to liquid chromatography coupled to mass spectrometry for the trace analysis of organic compounds in matrices of greater complexity. In our previous paper (Kumirska et al., J. Chemometr. 25 (2011) 636-643) we suggested using principal component analysis (PCA) to optimize the derivatization of six compounds (5 oestrogenic steroids and diethylstilbestrol) prior to GC-MS analysis. In the present work we applied a highly sophisticated model - 24 pharmaceuticals derived from six classes of drugs. The efficiency of different derivatization reactions was evaluated by PCA and compared with that obtained from cluster analysis (CA), the latter method being applied in this context for the first time. Derivatization using N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) and 1% trimethylchlorosilane (TMCS) in pyridine and ethyl acetate (2:1:1, v/v/v) for 30min at 60°C was found to be optimal. The SPE-GC-MS method was also validated and successfully applied to the analysis of selected pharmaceuticals in wastewater and surface waters in Poland.
authors.affiliation: Institute for Environmental and Human Health Protection, Faculty of Chemistry, University of Gdańsk, Sobieskiego 18/19, 80-952 Gdańsk, Poland. kumirska@chem.univ.gda.pl
authors.forename: Jolanta
authors.initials: J
authors.lastname: Kumirska
authors.forename: Alina
authors.initials: A
authors.lastname: Plenis
authors.forename: Paulina
authors.initials: P
authors.lastname: Łukaszewicz
authors.forename: Magda
authors.initials: M
authors.lastname: Caban
authors.forename: Natalia
authors.initials: N
authors.lastname: Migowska
authors.forename: Anna
authors.initials: A
authors.lastname: Białk-Bielińska
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Czerwicka
authors.forename: Piotr
authors.initials: P
authors.lastname: Stepnowski
mesh_terms: D016000:Cluster Analysis; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D004364:Pharmaceutical Preparations / Q000032:analysis / Q000737:chemistry / Q000302:isolation & purification; D025341:Principal Component Analysis; D015203:Reproducibility of Results; D012107:Research Design; D045483:Rivers / Q000737:chemistry; D052616:Solid Phase Extraction; D062065:Wastewater / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry / Q000302:isolation & purification
chemical_list: D004364:Pharmaceutical Preparations; D062065:Wastewater; D014874:Water Pollutants, Chemical