Your question about why glucose meters cannot be used for your application is a good one and here is some additional information on this question:
Here is a paper that describes how different types of glucose meters work.http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2141585/
The glucose meter is calibrated for a specific lot of test strips and the glucose in the sample is converted in the presence of oxygen enzymatically to gluconic acid and hydrogen peroxide and the results are measured colorimetically or by a change in conductivity. The meters measure glucose in a range of 0 to 450 mg/dL.
I don’t know why you could not use these strips for your samples, except I’m sure you would have to recalculate the results because the programming on the meters is designed for a blood matrix. It seems like you should be able to test a series of known concentrations of glucose to establish a calibration curve, and then test your samples and calculate the results. . However, part of the technology on these meters is proprietary and there may be something about the design of the system that would make it difficult to adapt to cellulose samples.
You would need to make sure that nothing in your sample interfered with the chemical reactions, so please let me know about the chemical composition and the enzymes that you are planning to use? What concentration of ions will be in the sample? Blood contains about 20 mM phosphate buffer plus 150 mM sodium chloride.
If you have a specific glucose meter available to use, I think it would be worthwhile to contact the manufacturer and ask about using it for your samples, or just try a sample of cellulose spiked with a known concentration of glucose and see what happens. Since there are several different types of glucose meters, it is possible that one or more would be suitable for your samples. Being able to use the glucose meter would make your experiment easy to do, although you would need lots of test strips, which would add to the cost of doing the project.
Here is a paper that includes a detailed protocol on how to do a glucose assay with a spectrophotometer:
You would need magnesium chloride, ATP, NADP, glucose 6-phosphate dehydrogenase, Tris buffer, hexokinase, pipettes, disposable cuvettes, and a spectrophotometer that measures at 340 nm. Please note that the authors report the range of their assay, the correlation coefficient, and the coefficient of variation. You would want to do something similar for your project. http://www.hindawi.com/journals/biomed/2009/430426/
Sigma offers a kit with all of the reagents based on the method described above. Do not order these reagents until you confirm that your sample will not interfere with the analysis: http://www.sigmaaldrich.com/etc/mediali ... k20bul.pdf
Here is the detailed protocol for the dinitrosolicylic colorimetric method, which is recommended for cellulose samples. You would need dinitrosalicylic acid, phenol, sodium sulfite, sodium hydroxide, potassium sodium tartrate, pipettes, disposable cuvettes, a hot water bath and a spectrophotometer that will read at 575 nm. http://www.eng.umd.edu/~nsw/ench485/lab4a.htm
Here is an abstract from an older paper that compared different methods of glucose analysis. The authors found that that reducing methods overestimated glucose concentrations and that the enzymatic methods gave the most accurate results.http://www.clinchem.org/content/28/12/2405
You can go to Google Scholar and do a search for glucose assays and related inquiries and you will find many more references that will provide you with good background information for your project.
One of the spectrophotometer methods would take an hour or two and you would have to set up a standard curve every time. However, you would get faster after the first time. If you were doing experiments over a period of time, you might want to freeze samples and test the glucose concentration for lots of samples at one time.
If you have access to the hydrometer, you might consider testing your samples to see if there is any difference in density when the cellulose is converted to glucose.
If you do try the glucose meter, let me know what happens.