Product description
Nitrate ions are extracted from the sample with a pH 9.6–9.7 alkaline buffer, activated charcoal is added to remove pigments, and a precipitant is used to remove proteins and other interfering substances. Utilizing the characteristic that nitrate and nitrite ions have equal absorption wavelengths at 219nm in the ultraviolet region, the absorbance of the extract is measured. The result represents the combined absorbance of nitrate and nitrite, and since the nitrite content in fresh vegetables and fruits is negligible, it can be disregarded. The measured result is the absorbance of nitrate, and the nitrate content is calculated from the standard curve.
Additional Materials and Equipments Required
Microplate reader, 96-well UV plate (for measurements under UV wavelengths), distilled water, room temperature centrifuge, reciprocating shaker.