[Araconan]

So one of my high school assignments today was to determine the percentage of sucrose in a block of gum. Instead of going by the conventional method (chewing, and measuring before and after masses of the gum), I thought I'd somehow precipitate the sugar out, and then determine the percentage composition that way.

With that, I have a few questions. First, what I was thinking was using a strong acid to first dissolve the gum. Would this work? If not, what solutions would dissolve bubble gum?
Now after I have the gum dissolved, what would react with sucrose to form a precipitate (since sucrose isn't a reducing sugar, benedict's solution wouldn't work)?

Thank you in advance.

[Sophia7X]

I don't think that's going to work. Something like HCl can take flavoring and coloring out, but it won't dissolve the  gum. On the other hand, sulfuric acid completely destroys the gum (turns it into black porous carbon)

[Araconan]

Hm, if HCl could take the flavoring out, technically that means that it can dissolve the gum to the point atleast where the sucrose is separated from the gum right?

Also, would a strong concentration of acetic acid work? Is there any organic solvents that might work?

[Sophia7X]

Yes, but that essentially fulfills the purpose of chewing the gum and letting your saliva dissolve the sugar. Except HCl is going to take out other things, except the gum base. Probably better just to chew the gum until all flavor is gone then let it dry.

Not sure about acetic acid, but if HCl won't do much, I doubt acetic acid would either.

I believe you can dissolve the sugar in the gum with a boiling solution of alcohol, but that will take out other polar components as well. I don't think that'll have a huge impact on results  since gum is so light anyway and your scale probably cant measure past 2 decimal points.

[Sircodekill]

1. Dry chew gum at 120ºC for several hours
2. Pulverize it
3. Dilute it on HCl 1 or 2M to hidrolize glycosidic bond
4. Make a normal chromatography with silica (i wish you can separate fructose of glucose with more/less polar eluent)
5. Get isolated glucose or the first that falls (you don't need both, since 1 mole of glucose means 1 mole of sucrose)
6. Crystallize it on rotavap
7. Check melting point
8. Weight or titrate.
9. Do the calculus to know initial concentration

I'm not sure you can do step 4 easily, so check it on thin layer chromatography with fructose/glucose solutions.
Step 1 and 2 are important to guarantee the fully dissolution of your analyte.

[Araconan]

1. Dry chew gum at 120ºC for several hours
2. Pulverize it
3. Dilute it on HCl 1 or 2M to hidrolize glycosidic bond
4. Make a normal chromatography with silica (i wish you can separate fructose of glucose with more/less polar eluent)
5. Get isolated glucose or the first that falls (you don't need both, since 1 mole of glucose means 1 mole of sucrose)
6. Crystallize it on rotavap
7. Check melting point
8. Weight or titrate.
9. Do the calculus to know initial concentration

I'm not sure you can do step 4 easily, so check it on thin layer chromatography with fructose/glucose solutions.
Step 1 and 2 are important to guarantee the fully dissolution of your analyte.

If I was to skip steps 4-7, and just place the pulverized gum into a 1M solution of HCl, and then titrate it with Benedict's Solution, would I still get similar results?