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Measurement of Nanoparticle Concentration Using Quartz Crystal Microgravimetry



Vytautas Reipa, Geoffrey Purdum, Jonghoon Choi


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.
Journal of Physical Chemistry B


Nanoparticles, concentration, colloidal solution, extinction coefficient, dry mass, quartz crystal microbalance


Reipa, V. , Purdum, G. and Choi, J. (2010), Measurement of Nanoparticle Concentration Using Quartz Crystal Microgravimetry, Journal of Physical Chemistry B, [online], (Accessed July 25, 2024)


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Created December 16, 2010, Updated February 19, 2017