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Publication Citation: Measurement of Nanoparticle Concentration Using Quartz Crystal Microgravimetry

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Author(s): Vytautas Reipa; Geoffrey Purdum; Jonghoon Choi;
Title: Measurement of Nanoparticle Concentration Using Quartz Crystal Microgravimetry
Published: December 16, 2010
Abstract: A common issue, encountered in nanoparticle-biological system interaction studies is accurate nanoparticle concentration expression, given the critical importance of the dose-response relationships. We present here the application of quartz crystal microgravimetry (QCM) to accurately measure nanoparticle concentration in a colloidal suspension. Application of a small drop of the nanoparticle suspension in volatile solvent to the crystal surface leaves a dry nanoparticle residue after solvent evaporation and a shift in the crystal resonant frequency is recorded. Instrument was calibrated using a dilution series of Si and Ag nanopowder in methanol, rhodamine B in methanol and ferrocene in cyclohexane. The QCM showed a linear response for nanoparticle concentrations in the range from 5 to 1300 g/ml. Method was used to determine the molar concentrations of size selected octyl-terminated Si nanocrystal samples with diameters in the range from 1.1 to 14.8 nm and calculate size dependent nanocrystal extinction coefficients.
Citation: Journal of Physical Chemistry B
Volume: 114
Issue: 49
Pages: pp. 16112 - 16117
Keywords: Nanoparticles, concentration, colloidal solution, extinction coefficient, dry mass, quartz crystal microbalance
Research Areas: Chemistry
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