Pre-Equilibrium Solid-Phase Microextraction of Free Analyte in Complex Samples: Correction for Mass Transfer Variation from Protein Binding and Matrix Tortuosity

The accurate measurement of free analyte concentrations within complex sample matrixes by pre-equilibrium solid-phase microextraction (SPME) has proven challenging due to variations in mass uptake kinetics. For the first time, the effects of the sample binding matrix and tortuosity on the kinetics o...

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Bibliographic Details
Published in:Analytical chemistry (Washington) 2011-05, Vol.83 (9), p.3365-3370
Main Authors: Zhang, Xu, Oakes, Ken D, Hoque, Md Ehsanul, Luong, Di, Metcalfe, Chris D, Pawliszyn, Janusz, Servos, Mark R
Format: Article
Language:English
Subjects:
Absorption
Analytical chemistry
Animals
Binding sites
Cattle
Chemical compounds
Chemistry
Environmental Pollutants - analysis
Environmental Pollutants - chemistry
Environmental Pollutants - isolation & purification
Exact sciences and technology
Extraction processes
Fishes
Muscles - chemistry
Protein Binding
Proteins
Reaction kinetics
Serum Albumin, Bovine - chemistry
Solid Phase Microextraction - methods
Tissues
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Summary:The accurate measurement of free analyte concentrations within complex sample matrixes by pre-equilibrium solid-phase microextraction (SPME) has proven challenging due to variations in mass uptake kinetics. For the first time, the effects of the sample binding matrix and tortuosity on the kinetics of analyte extraction (from the sample to the SPME fiber) are demonstrated to be quantitatively symmetrical with those of the desorption of preloaded deuterated standards (from the fiber to the sample matrix). Consequently, kinetic calibration methods can be employed to correct for variation in SPME sampling kinetics, facilitating the application of pre-equilibrium SPME within complex sample systems. This approach was applied ex vivo to measure pharmaceuticals in fish muscle tissues, with results consistent with those obtained from equilibrium SPME and microdialysis. The developed method has the inherent advantages of being more accurate, precise, and reproducible, thus providing the framework for applications where rapid measurement of free analyte concentrations (within complicated sample matrixes such as biological tissues, sediment, and surface water) are required.
ISSN:0003-2700
1520-6882
DOI:10.1021/ac2004899