How to quantifying alcohol content in pre-moistened wipes?

I am trying to figure out the best way to perform alcohol determination on alcohol pre-moistened wipes with respect to USP <611>. What would be the best way to extract the alcohol from the pads for quantification?

 

Anyone have experience with this?

  • Hi chemist123,

    I moved your post to an application area for better visibility. 

    Regards

    James 

  • My first thought might be to use a headspace autosampler.

  • Could water be used as a diluent in the case of headspace? i.e place the pad in a 20 mL headspace vial containing 5 ml of water. I am a bit worried because of it's expansion. 

  • My first thought is to run it like you would a blood alcohol sample.  You would place a know amount of the wipe, either by placing a specified area, or weight of wipe, to the headspace vile.  Then  perhaps a fixed volume of water with an appropriate  internal standard ( for example 1-propanol if that is not an ingredient in the wipes).  Start out with Headspace and GC acquisitions parameters similar to a blood alcohol analysis.  You would next optimize the headspace parameters and GC inlet parameters.  Standards used to calibrate the method could be added with the water along with the same amount of dry wipe material to create a matrix matched calibration if needed. 

  • Hi Chemist 123,

     

    FTIR has proven to be a fast and easy solution to quantify alcohol in hand sensitizers. I think it could also be applied to alcohol wipes. If you use an ATR accessory you could even measure the wipes directly without any extraction.

     

    All you would need is a series of wipes with known alcohol content (as standards) covering the concentration range you are interested in. Next, measure FTIR spectra of these wipes and create a calibration curve based on a suitable peak in the spectrum (e.g. ca. 1050 cm-1 for ethanol and ca. 1130 cm-1 for isopropanol). The calibration curve can then be used to determine the alcohol concentration in your wipe samples.

     

    I hope that helps.

    Fabian

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