Science Buddies: "Ask an Expert"

Hi,

I'm performing an experiment that involves measuring the glucose content in potatoes over time. I have access to a glucose meter and some test strips, and I know this method works. But, for my experiment I would need about 800 test strips (assuming I do my measurements in triplicate). Even if I do not, the test strips are very expensive and so I was looking for an alternate test method. I already called the glucose meter company and they are willing to donate 1 vial of test strips, but that is all.

I saw another way to measure glucose levels is with a urine test strip. But, I see that 1) these test strips are also expensive too and 2) you have to compare the color you get on the test strip with a color chart. That method has a lot of error in it and I'm looking to get a rather precise measurement of glucose.

I thought of measuring starch instead of glucose since the starch just gets converted to glucose over time. What I've seen so far involves testing for the presence of starch, not the amount of starch. But, there could be other tests out there. I've seen some tests that involve a spectrophotometer, but I do not have access to one.

Does anyone know of an inexpensive, accurate and fast method to test for the prescence of glucose or starch? Finally, I'm performing this experiment at home, so my access to various equipment is limited.

Thanks in advance!

Hi,

Here is one alternative glucose assay:

http://terpconnect.umd.edu/~nsw/ench485/lab4a.htm

http://faculty.ksu.edu.sa/aabulhamd/Doc ... 0(353).pdf

http://chemeducator.org/sbibs/s0009004/ ... 0239ld.htm


This one is probably too expensive for you:

http://www.biovision.com/updated/newkits/glucose.html

http://www.biovision.com/pdf/K606.pdf

Another expensive one:

http://www.caymanchem.com/app/template/ ... 009582/a/z

Here is a comparison of 4 glucose assays:

http://www.clinchem.org/cgi/reprint/28/12/2405

You may find this patent useful:

http://www.freepatentsonline.com/3738809.html

Most of the alternative methods for glucose require use of a spectrophotometer. Id you don’t have access to one, the only alternative I can suggest is to, if the color involved is in the visible, is to prepare a standard set of samples at known concentrations, and then compare colors by eye between standard and sample to find the closest match possible. This won’t be very accurate.

My best advice is to find a mentor at a local college or junior college who can offer you access to a lab and spectrophotometer. Here is Science Buddies advice on how to do this:

https://www.sciencebuddies.org/science- ... tors.shtml

Sorry not to have a better answer. Best wishes for success on the project.

Best regards,

Barrett L. Tomlinson

Here is a link to a project on measuring glucose in food using glucose test strips. https://www.sciencebuddies.org/science- ... p049.shtml The urine glucose test strips is consider a semi-quantitative test and whether it will work depend on the accuracy/precision that is require for your experiment. If accuracy/precision is a concern and the cost of strip is out of budget you can ask a local hospital lab to see whether they can donate test strips to you for your experiment since most hospital buy in bulk quantity therefore they usually get deep discount from their supplier.

Michael

hello, I've found the qualified products in Creative Diagnostics Inc., and it was detected by fast quantitative ELISA, I've used the hep ELISA and I found the quality and the service was well. And maybe it's useful for you, here is the site: http://www.creative-diagnostics.com/sea ... p=s0&tab=0