LaMotte 1200-NA COLORIMETER - Manual (Page 4)

NITRATE-NITROGEN
TEST METHOD SPECIFICATIONS
APPLICATION
This method determines nitrate levels in drinking, surface, saline waters, domestic, and
industrial waters.
RANGE
0 - 3.0 ppm Nitrate Nitrogen (Range can be extended by dilution.)
METHOD
Powdered cadmium is used to reduce nitrate to nitrite. The nitrite that is originally
present plus reduced nitrate is determined by diazotization of sulfanilamide and nitrite
followed by coupling with N-(1 naphthyl) -ethylenediamine dihydrochloride to form a
highly colored azo dye which is measured colorimetrically.
HANDLING & PRESERVATION
Analysis should be made as soon as possible. If analysis cannot be made within 24 hours,
the sample should be preserved by refrigeration at 4°C. When samples must be stored for
more than 24 hours, they can be preserved by adding 2 mL of concentrated sulfuric acid
per liter of sample. For best results, the analysis for nitrate should be determined at
temperatures between 20°C and 25°C.
INTERFERENCES
Nitrite interferences at all levels. Strong oxidizing and reducing substances interfere.
Low results might be obtained for samples that contain high concentrations of iron and
copper.
LaMOTTE COMPANY
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PO Box 329 • Chestertown • Maryland • 21620 • USA
800-344-3100 • 410-778-3100 (Outside U.S.A.) • Fax 410-778-6394
Visit us on the web at www.lamotte.com
06.09 #63677-01