Technical Summary: Industrial Glutamine Analysis (Bulletin ref. TB118727B)
 

A simple and rapid enzymatic analysis for L-glutamine in a variety of biological fluids, e.g. for the monitoring and control of culture media and fermentation processes in biotechnology.
 

Name:
Code:
Size:

Industrial Glutamine
GMRD-151
2 x 30 tests; 140 analyser cycles

Instruments:
 

GM8 Series analysers
 

Principle:

i) Ammonia, liberated from L-glutamine by the enzyme glutaminase (GLU), is converted to L-glutamate by a-ketoglutarate in the presence of glutamate dehydrogenase (GLDH) and excess NADH in a brief pre-reaction:
 

ii) Under the conditions of the assay, the rate of oxidation of excess NADH by peroxidase (POD) is inversely proportional to the total ammonia present:

A sample blank without GLU measures endogenous ammonia and other NADH consuming reactions and the L-glutamine concentration is obtained by difference.
 

Samples:
Sample volume:
Analytical Range:
Precision:
Detection Limit:
Sensitivity:

Aqueous solutions (pH 5 - 7), culture fluid, etc.
25 µl
0.5 - 20.0 mmol/L
Typical within-run C.V. = 1 - 2 % @ 8 mmol/L
0.2 mmol/L
1 µmol/L (analyser)

Reagent Stability:

Shelf-life 9 months unopened when stored at 0 - 5°C. Reconstituted GLDH/NADH/a-ketoglutarate, 7 - 10 days (2 vials) if stored at 0 - 5°C.
 

Note:

i) For clinical (plasma) L-glutamine analysis, please refer to details of product GMRD-150.
ii) Sample opacity or turbidity presents no problem since the sensor system is electrochemical rather than spectrophotometric.