I am looking for a simple way to distinguish between glucose and fructose samples. Currently, I am doing that by melting temperature method. Can anybody suggest me some easy way to do that?
One of the simplest ways would be bromine-water test. Bromine water oxidizes glucose to gluconic acid, hence decolorize the solution. Being a mild oxidizing agent, Bromine water is not capable of oxidizing fructose (ketone).
Go for Seliwanoff's Test. It is based on the simple fact that when heated, ketose sugars are more rapidly dehydrated than aldoses. After acidic hydrolysis of both, we add a pinch of resorcinol(0.5%) and concentrated HCl(3N). Fructose reacts to give a deep red cherry colour whereas Glucose reacts slightly to produce a faint pink colour.
Go for Osazone test.... add phenylhetrazine +sodium acetate + acetic acid...if yellow precipitate appears within two minutes of boiling in waterbath (needle shape crystals)then the sample is Fructose.. if yellow precipitate appears between 5 to 10 minutes of boiling in waterbath (broom shaped crystals)its glucose.