Because sugars are not volatile, so you can't use GC. I have very much experience on HPLC of sugars, if you need.

yes please

Sugars are indeed not volatile but can be derivatized to make them so. I prefer GC.

Here is my method based on the aldonitrile method (PAAN derivatives)

I've more or less completed my method. I take 0.5 ml of sample and 0.2ml ribitiol ITSD and blow it down to dryness at 45 deg C with nitrogen

add 200ul of 2% hydroxylamine pyridine incubate 1 hour at 90 deg C

cool

add 200 ul of acetic anhydride and incubate 1 hour at 90 deg C

cool and add 1ml water and 500 ul of methylene chloride. 

Inject the methlene chloride layer. I use a db-5 column. monosaccharides and sugar alcohols come off ~ 200-260 deg C and disacchardies 315 deg C. I am planning to eventually get a high temp DB5 to do maltotriose. I am also eventually looking to replace the methylene chloride with either toluene or ethyl acetate.

Fructose seems to work well enough to quantitative. I get linearity of .996 vs .999-.9999 for the rest. The LOD is higher for it as it is split into two smaller peaks for the cis and trans oxime peracetate.