The last few days i have determined reduced sugar content from grass that was both hydrolyzed with sulfuric acid as from grass extracted with distilled water. Because the calculated concentrations of both extractions did not differ from each other, i decided to do a test where i used maltose and fructose as a positive control and dextrose as the standards set. This test was intended to verify if the method used is valid. The determination of reducing sugars is performed using dinitrosalicyclic acid method. Is there a reference value for both fructose and maltose in the literature?
I am not sure if there are reference values as the content varies with sample analysed and this will be reflected by the strength of colour development by DNSA, did you say you are getting positive colour development with fructose?
Thanks Isabella. I indeed had a positive color development for both fructose and maltose. My question is in fact what are the reference values for both fructose and maltose in other words what's the content of reducing sugars in both? This experiment was only to validate the DNS method is perfect otherwise i would switch to Fehling method.
Theoretically, the reducing value of a mole of aldose should be the same, regardless of method used to measure it. The problem is that some methods respond more accurately than others. The DNS method is notoriously poor in that regard. In particular, its response to oligosaccharides of various degree of polymerization (e.g., glucose, maltose, maltotriose, maltotetraose, etc.) is not linear. See, for example, McIntyre et al., Carbohydrate Research 380 (2013) 118–123. If you want accurate reducing values across a range of sugars, I would suggest the Somogyi-Nelson copper-arsenomolybdate method.
Sugar Meal Composition of Five North Central Florida Mosquito Species (Diptera: Culicidae) as Determined by Gas Chromatography
- July 1999
- Journal of Medical Entomology 36(4):462-7
- DOI: 10.1093/jmedent/36.4.462
- D A Burkett
- D L Kline
- 📷David Arthur Carlson
- This publication describes GC analysis of sugar meals in wild mosquitoes.
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