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Some Operational Questions

Dear OpenQCM, I recently purchased an OpenQCM starter kit and additional quartz crystal sensors for a project I am working on at the University of Waterloo in Ontario, Canada. I have a couple of questions regarding operation: 1. Do you know the values for electrode area, and quartz density/shear modulus/wave velocity (constants in the Saurbrey equation) for your sensors? I gather that I can determine the frequency shift from your software, but I will need these constants to estimate the mass bound to the sensor. 2. I noticed that the bottom of the QCM recommends against use with ethanol. Is the reason for this incompatibility just due to contact with the O-rings? Do you have a guide of what solvents can and cannot be used with the OpenQCM? 3. Do you have a recommended range of flow rates (mL/min or mL/hour) for operating the OpenQCM? 4. Is there a way to operate the OpenQCM without continous injection, i.e. a static sample holder? Thanks, Stuart

Comments

  • Dear Stuart,

    This is Raffaele from openQCM team, very nice to meet you. First of all thank you for being our welcome customer.

    Here my answers:

    1. technical specifications of openQCM quartz crystal sensors in Sauerbrey's equation

    electrode area: A = 0.283 cm^2
    quartz density: ρQ = 2.648 g * cm^-3
    shear modulus: μQ = 2.947 x 10^11 g * cm^-1 * s^-2
    wave velocity: vQ = 3.336 x 10^5

    In addition you can find more info on Sauerbrey's equation by visiting our wiki page here
    http://quartzcrystalmicrobalance.org/index.php?title=Sauerbrey_Equation

    also find attached an excel file with all the technical specifications mentioned above, in order to calculate mass responsivity, surface mass responsivity and mass saturation based on Sauerbrey's equation

    2. No, it does not depends on the oring but it depends on the transparent fluidic cell. openQCM standard fluidic cell is made in Poly(methyl methacrylate) - plexiglass - which swells and dissolves in many organic solvents, like ethanol. For this reason it is generally recommend to not use organic solvents with openQCM fluidic cell. Anyway, if you are using organic solvents for your application please let me know what they are and what the concentration you are thinking to use, thanks !

    3. We used to test openQCM using a very slow flow rate during the test. We recommend a typical flow rate of 0.1 ml/min, of course lower values is totally ok. But higher value of flow rate can cause a very noisy frequency signal and not good working condition for openQCM.

    4. Yes of course, you can inject your sample in the measurement chamber using our tubing connected to a peristaltic pump, syringe pump or whatever you want. Then you would stop the flow, wait for the steady state and start to acquire your data in static condition.

    Let me know if it helps and feel free to contact me anytime for further info.
  • Hi Raffaele,

    Thanks very much for the quick response, this information was very helpful.

    Best regards
  • ... and happy New Year ;-)
  • edited December 2016
    You are welcome and happy New Year too!!!
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