Original Paper

Analytical and Bioanalytical Chemistry

, Volume 389, Issue 2, pp 441-446

First online:

Molecularly imprinted sol–gel nanoparticles for mass-sensitive engine oil degradation sensing

  • Peter A. LieberzeitAffiliated withDepartment of Analytical Chemistry and Food Chemistry, University of Vienna
  • , Adeel AfzalAffiliated withDepartment of Analytical Chemistry and Food Chemistry, University of Vienna
  • , Gerd GlanzingAffiliated withDepartment of Analytical Chemistry and Food Chemistry, University of Vienna
  • , Franz L. DickertAffiliated withDepartment of Analytical Chemistry and Food Chemistry, University of Vienna Email author 

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Abstract

Titanate sol–gel layers imprinted with midchain carbonic acids have proven highly useful for detecting engine oil degradation processes owing to selective incorporation of oxidised base oil components. Synthesising the material from TiCl4 in CCl4 and precipitating with water leads to imprinted TiO2 nanoparticles with a diameter of 200–300 nm. Replacing the water by a 1 M ammonium hydroxide solution reduces the average particle size to 50–100 nm with retention of the interaction capabilities. Experiments with the latter solution revealed that the 100-nm particles take up substantially more analyte, indicating a size-dependent phenomenon. As the number of interaction sites within each material is the same, this cannot be a consequence of thermodynamics but must be one of accessibility. The sensor characteristic of water-precipitated particles towards engine oil degradation products shows substantially increased sensitivity and dynamic range compared with the corresponding thin films. Coating quartz crystal microbalances with such nanoparticle materials leads to engine oil degradation sensors owing to incorporation of acidic base oil oxidation products. Interaction studies over a large range of layer thicknesses revealed that both the absolute signal and the steepness of the correlation between the sensor signal and the layer height is 2 times higher for the particles.

https://static-content.springer.com/image/art%3A10.1007%2Fs00216-007-1274-3/MediaObjects/216_2007_1274_Figa_HTML.gif
Figure

Generation of molecularly imprinted sol–gel nanoparticles

Keywords

Titanate sol–gel Nanoparticles Engine oil degradation sensor Mass-sensitive detection Sensitivity enhancement