title: Dynamic hollow-fibre liquid phase microextraction of dinitrophenols from human plasma: optimization of an extraction flow system using experimental design methodology.
abstract: The utility of a dynamic hollow-fibre liquid phase microextraction method (optimized using a four-variable experimental design and response surface modelling) for extracting dinitrophenolic compounds from human plasma samples was evaluated. The investigated variables were donor phase salt concentration (10-400 mM), donor phase pH (2-6), acceptor phase pH (7-12), and donor/acceptor phase flow rates (30/7.5 to 70/17.5 microL min(-1)). Four dinitrophenol pesticides were used as model substances at concentrations of 0.1 microg mL(-1) in spiked human plasma samples. Extraction efficiencies ranging from 42 to 77% with RSDs below 9 were achieved with the optimized method. The flow rate and acceptor pH were shown to strongly affect the extraction efficiency for all compounds, while the donor phase pH and salt concentration had minor effects. With a well-defined acceptor phase pH and flow rate the system exhibited high robustness. The limits of quantification for the investigated compounds, using the presented extraction method followed by liquid chromatography/electrospray ionization mass spectrometry in selected ion monitoring mode, ranged from 0.05 to 0.1 microg mL(-1) plasma.
authors: Department of Analytical Chemistry, Stockholm University, 106 91 Stockholm, Sweden.
authors: Helena
authors: H
authors: Hansson
authors: Malene
authors: M
authors: Lagerström
authors: Magnus
authors: M
authors: Aberg
authors: Ulrika
authors: U
authors: Nilsson
mesh_terms: D005591:Chemical Fractionation / Q000379:methods*; D002853:Chromatography, Liquid; D004140:Dinitrophenols / Q000032:analysis / Q000097:blood* / Q000302:isolation & purification*; D005659:Fungicides, Industrial / Q000032:analysis / Q000097:blood* / Q000302:isolation & purification*; D006801:Humans; D016014:Linear Models; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D004140:Dinitrophenols; D005659:Fungicides, Industrial