Primary Amino Nitrogen

This method is available only as a kit for determination of NOPA in wine or juice using the rAPID-T™ analyzer. It is also used by breweries instead of the FAN test. The range of the method is 10 to 200 mg/L. Dilute samples above this range. For specific information regarding reagent composition, precautions and performance, please refer to the manufacturer insert located inside the kit.

Summary of Method

The determination of NOPA is based on its reaction with free amino acids in the sample, in the presence of N-acetyl-L-cystein and phthaldiadehyde, leading to the formation of isoindole derivatives in stoichiometric concentration with respect to free amino groups. Absorbance increase at 340nm from isoindole derivatives is proportional to the concentration of NOPA present in the sample, and can be measured photometrically. Blank readings in the method eliminate interference from colored wine samples.

Availability

Use: 70-9503-13K  Amino Nitro (NOPA), SteroGlass, Reagent Kit on the rAPID-T.