Measurement of the Free Concentration Using Solid-Phase Microextraction:  Binding to Protein

1996 ◽  
Vol 68 (24) ◽  
pp. 4463-4467 ◽  
Author(s):  
Wouter H. J. Vaes ◽  
Eñaut Urrestarazu Ramos ◽  
Henk J. M. Verhaar ◽  
Willem Seinen ◽  
Joop L. M. Hermens
Keyword(s):  
Solid Phase Microextraction ◽  
Solid Phase ◽  
Free Concentration

Role of nanoparticles in analytical solid phase microextraction (SPME)

2013 ◽  
Vol 10 (2) ◽  
pp. 120 ◽  
Author(s):  
Katarzyna Zielińska ◽  
Herman P. van Leeuwen
Keyword(s):  
Solid Phase Microextraction ◽  
Solid Phase ◽  
Aqueous Media ◽  
Aqueous Dispersion ◽  
Sio2 Nanoparticles ◽  
Sample Solution ◽  
Confocal Laser ◽  
Aqueous Sample ◽  
Free Concentration

Environmental context Organic hydrophobic compounds are present in water in low concentrations, and they can be analysed by means of a preconcentration technique called solid phase microextraction. We investigate the role of sorbing nanoparticles in the solid phase microextraction analysis of organic compounds. Our results show that nanoparticles are capable of partitioning between water and the solid phase and aggregate at the interface leading, most probably, to substantial overestimation of the original sample concentration. Abstract Solid phase microextraction (SPME) is commonly used to measure the free concentration of fairly hydrophobic substances in aqueous media on the basis of their partitioning between sample solution and a solid phase. Here we study the role of nanoparticles that may sorb the analyte in the sample medium. As an example case, the solid phase poly(dimethylsiloxane) (PDMS) is exposed to an aqueous dispersion containing silica nanoparticles with 10-nm radius. Confocal laser microscopic data show that these SiO2 nanoparticles do enter the PDMS and partition between the sample solution and solid phase. Moreover, they form aggregates at the surface of the solid phase. The overall partitioning of the SiO2 nanoparticles in the aqueous sample–PDMS system is examined and potential effects on the SPME analysis of organic analytes are indicated.

Solid-phase microextraction for assessment of plasma protein binding, a complement to rapid equilibrium dialysis

Bioanalysis ◽  
2021 ◽  
Author(s):  
Sheelan Ahmad ◽  
Daniel Baker ◽  
Darragh Murnane ◽  
Neil Spooner ◽  
Ute Gerhard
Keyword(s):  
Protein Binding ◽  
Plasma Protein Binding ◽  
Plasma Protein ◽  
Solid Phase Microextraction ◽  
Solid Phase ◽  
Equilibrium Dialysis ◽  
Free Concentration ◽  
Rapid Equilibrium

Aim: Determination of plasma protein binding ( PPB) is considered vital for better understanding of pharmacokinetic and pharmacodynamic activities of drugs due to the role of free concentration in pharmacological response. Methodology & results: Solid-phase microextraction (SPME) was investigated for measurement of PPB from biological matrices and compared with a gold standard approach (rapid equilibrium dialysis [RED]). Discussion & conclusion: SPME-derived values of PPB correlated well with literature values, and those determined by RED. Respectively, average protein binding across three concentrations by RED and SPME was 33.1 and 31.7% for metoprolol, 89.0 and 86.6% for propranolol and 99.2 and 99.0% for diclofenac. This study generates some evidence for SPME as an alternative platform for the determination of PPB.

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