Technical Summary: Sucrose Analysis (Bulletin ref. TB120215)
 

A simple two-step enzymatic assay for sucrose in aqueous solutions or extracts.
 

Name:
Code:

Sucrose
GMRD-105 (50-100 tests)
GMRD-107 (150-300 tests)

Instruments:
 

All GM8 Series analysers
 

Principle:

i) Sucrose, a disaccharide, is stoichiometrically hydrolysed by Invertase (ß-fructosidase) to a-D-glucose and fructose in a simple pre-reaction. Under the special buffer conditions used, mutarotation to ß-D-glucose rapidly occurs:
 

ii) In the presence of molecular oxygen, ß-D-glucose is oxidised by the enzyme glucose oxidase to gluconic acid and hydrogen peroxide:

Under the conditions of the assay, oxygen consumption is directly proportional to glucose concentration, which relates directly to the original sucrose concentration. Any glucose originally present is measured directly after simple aqueous dilution as in the pre-reaction.
 

Samples:

Aqueous solutions and extracts

Sample volume:
Pre-reaction time:
Analysis time:
Calibrant:

5 µl or 10 µl
15 minutes
20 seconds
5 % W/V sucrose

Linearity:
 

ca 15 % W/V sucrose as extract
 

Reagent Stability:

Shelf-life 12 months unopened stored at 0 - 5°C. Reconstituted invertase,
3 - 4 days (4 vials) if stored at 0 - 5°C. Aliquots may be frozen for extended life.
 

Note:

i) Sample opacity or turbidity presents no problem since the sensor system is electrochemical rather than spectrophotometric.
ii) Endogenous glucose, if present, should be determined as a sample 'blank',
i.e. extract diluted pro-rata in water instead of ß-fructosidase.