Glucose + Fructose

This method is available in a kit only for the rAPID-T system. The range of the method is 0.1 to 6.0 g/L as glucose. Dilute samples above this range. 


Wine samples are mixed with buffer at pH 7.8 containing NADP+ and ATP. Subsequent addition of the enzymes phosphoglucose isomerase (PGI), glucose-6-phosphate dehydrogenase (G6PD) and hexokinase (HK) convert glucose and fructose to glucose-6-phosphate (G-6-P). G-6-P is oxidized to gluconate-6-phosphate resulting in the formation of NADPH. The absorbance of NADPH at 340 nm is directly proportional to the glucose + fructose in the sample.


Instrument Method Reference Range
Astoria 300 see Residual Sugar  
Astoria 2 see Residual Sugar  
rAPID-T 70-9400-13K  0.1 - 6.0 g/l