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DLPNIRNANOEVM: Reference scanning with plastic packet

6044530
Prodigy 70 points
Part Number: DLPNIRNANOEVM


Dear all,

I am currently using the DLPNIRScan nano evm to obtain data from powdered turmeric. 

I had used the factory reference scan settings for obtaining data from 2 different batches of turmeric. 

The packaging plastic was very different in both cases and for the second one, which had a much thicker plastic, I got very unsatisfactory results from my statistical model.

How can I combat this issue? And how exactly do I measure a reference? Do I just use the empty plastic packet for reference? Or should there be a reference material inside the plastic which is then scanned.

Any help would be appreciated.

  • 0
    TI__Expert 5485 points

    Hi Utsav,

    Ideally, in case of different packaging, you should scan samples of turmeric without the plastic. Otherwise, you'd be unable to differentiate between the variations in measurements due to the different batches of turmeric from the variations due to the packaging.

    Regards

    Azad

  • 0 in reply to Azad
    Prodigy 70 points

    Hi Azad.

    Thanks for the reply.

    Considering that the sample is a powder and that I would like to avoid physical contact between it and the device, do you know how I could do this?

    Could I subtract the reference scan of the empty packets in both cases?

    Thanks and regards,

    Utsav

  • 0 in reply to 6044530
    TI__Genius 10925 points

    Hi Utsav,

    To scan turmeric in a plastic packet, you have to first perform a reference scan in the SAME TYPE OF PLASTIC packet. This is done by obtaining a spectralon sample and placing it inside a plastic packet, and then doing a reference scan under the "Scan" page on the NIRScanNano GUI. Kindly keep in mind, that even with the same type of plastic packets, the transparency, composition and other optical characteristics may vary. So less accuracy is expected compared to the scans done without any plastic packet.

    Thanks & Regards,

    Hirak.

  • 0 in reply to Hirak Biswas
    Prodigy 70 points

    Hi Hirak,

    Thanks for your response. Had a couple of questions.

    1. After doing so, I was looking at the 'Reference Signal (unitless)' column which had different intensity readings for each scan. I would assume they would be the same if the reference was the same. Is something wrong here and if so should I manually calculate the absorbance as a=-log(I/I(nought))

    2. If I calibrate with the reference then I dont need to subtract the absorbance of just the plastic right? This is a common practice in some papers I have read, would like to know if I have to do the same or if the TI application does it itself.

    Thanks

    Utsav

  • 0 in reply to 6044530
    TI__Genius 10925 points

    Hi Utsav,

    Kindly find the answers to your questions below:

    1. If you have selected the same reference (either factory or previous, same for all the cases) then the reference signal column should be identical. We can confirm this behavior from our end. Kindly double check that you have selected one of the above mentioned for ALL the cases, without scanning new references in between.

    2. If you scan a reference by placing the Spectralon sample inside the same type of plastic packet and use this reference to scan samples inside plastic packets, then you don't need to manually subtract anything. The reference signal will take care of it. 

    Hope this helps,
    Thanks & Regards,

    Hirak.

  • 0 in reply to Hirak Biswas
    Prodigy 70 points

    Dear Hirak,

    Thanks so much your help on this topic. The online material in research papers etc is not always consistent but I guess that is because it varies from device to device. 

    1. I guess there must have been some change in the reference scan settings. I will sort that out.

    2. Alright, so the final result can be used directly for the absorbance values.

    I am currently in the process of purchasing a reference standard from Spectralon, till then is it possible to use any other cheaper substitute for the same. I recall a similar thread suggesting alternate materials like whitening fluid or liquid paper although it seems unreliable on the face of it. 

    Would you happen to know any robust alternate options for this?

    Thanks again for your clear answers and help so far.

    Regards,

    Utsav

  • 0 in reply to 6044530
    TI__Genius 10925 points

    Hi Utsav, 

    If we were able to resolve your queries, kindly mark the resolving answers as "This resolved my issue".  

    I'll investigate and let you know if any alternate material can be used for this purpose shortly. 

    Thanks & Regards,

    Hirak.

  • 0 in reply to Hirak Biswas
    Prodigy 70 points

    Sure Hirak!

    Thanks.

    Look forward to hearing from you soon.

    Utsav

  • 0 in reply to 6044530
    TI__Mastermind 23090 points

    Hi Utsav,

    Avian Technologies does provide some excellent alternate for reflective standard.    Fluorilon-99w is a good alternative. Please reach out to them directly for further information

    https://aviantechnologies.com/product-category/standards/reflectance-standards/

    A simple low cost alternative would be wite-out on a highly reflective surface like reflector of a lamp or light. However, the performance will not be good because it  is not as uniform standard materials.

    regards,

    Vivek