Today is Nitrate day!

Hi CE341 students,

Today is Nitrate measurement day. Nitrate is the most completely oxidized form of nitrogen. It is formed during the final stages of biological decomposition, either in wastewater treatment facilities or in natural water supplies. Low-level nitrate concentrations may be present in natural waters. However, a Maximum Contaminant Level of 10 ppm nitrate-nitrogen has been established for drinking water by the USEPA. Fernando Almada and I have made a video for explaining how to measure it by using the Chemetrics handheld spec and the cadmium reduction method:

Nitrate is reduced to nitrite using cadmium as the reducing agent. The resulting nitrite concentration is then determined colorimetrically. This method is applicable to drinking and surface waters, as well as domestic and industrial wastes. Results are expressed as ppm (mg/L) NO₃-N or NO₃. (Note that if there is any pre-existing nitrite, this will be count as nitrate too)

References: ASTM D 3867-09, Nitrate-Nitrite in Water, Test Method B. APHA Standard Methods, 21^st ed., Method 4500-NO3^- E (2005).  USEPA Methods for Chemical Analysis of Water and Wastes, Method 353.3 (1983). www.chemetrics.com

Click here to see the video in youtube.

PS: the video may take few seconds to charge. Please, be patient. You can click on it if it does not autoplay