Can anyone answer some questions for me about quantitative analysis using paper based kits? I'm i...
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fieldlab asked on May 06, 2016 07:01
419 views | 0 answers | #13083
Can anyone answer some questions for me about quantitative analysis using paper based kits? I'm interested in the idea of using cameras (or a spectrometer) to provide quantitative data by transmitting light though paper rather than solution.
For example, the following url is a link to a 2009 paper from Analytical Chemistry:
"Quantifying Colorimetric Assays in Paper-Based Microfluidic Devices by Measuring the Transmission of Light through Paper"
I am part of a group of people interested in measuring agricultural contamination of waterways. The key chemical parameters that I am interested in are nitrate and phosphorus, with measurement accuracy needing to be ppm-ppb. The following quote from the paper suggests that paper-based kits may be something we could use. I realise that the application in the paper is quite different, but I'd appreciate a chemist having a look with our application in mind and receiving their views on the matter.
"This prototype transmittance colorimeter is inexpensive, rugged, and fully self-contained, and thus potentially attractive for use in resource-limited environments and
developing countries" (Ellerbee et al. 2009). - Sounds like us!
Hmm, interesting. I don't know much about paper assays, but this kit available online says:
Smallest Increment: Steps: 0, 0.15, 0.3, 1, 1.5, 3 ppm
would that be sensitive enough? It's available for $21.39. What are the drawbacks or limitations, if any, to paper based tests?
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Thanks for your reply @warren. There is pretty good discussion going on about this concept on hackaday for Pb detection in drinking water a la Flint.
Main advantage is objective digital measurement under controlled lighting. What about cheap cell phone screens a flat bed light source?
Would a cell phone screen be a really consistent spectrum? I wonder how much variability there is in manufacturing.
Yes, a good question @warren - possibly not, and I'm not sure how to find out, apart from buying a whole lot of cheap cell phones. I'll keep thinking about it!
We're starting to compile a lot of different sensors and testing methods here -- could be of help!
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DIY methods for nitrate detection in food?
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