LaMotte SMART 2 - Manual (Page 189)

NITRATE-NITROGEN–LOW RANGE
CADMIUM REDUCTION METHOD • CODE 3649-SC
QUANTITY CONTENTS CODE
2 x 60 mL *Mixed Acid Reagent *V-6278-H
5 g *Nitrate Reducing Reagent *V-6279-C
1 Spoon, 0.1 g, plastic 0699
1 Dispenser Cap 0692
*WARNING: Reagents marked with an * are considered to be potential health
hazards. To view or print a Material Safety Data Sheet (MSDS) for these reagents go to
www.lamotte.com. To obtain a printed copy, contact LaMotte by e-mail, phone or fax.
Nitrogen is essential for plant growth, but the presence of excessive amounts in
water supplies presents a major pollution problem. Nitrogen compounds may
enter water as nitrates or be converted to nitrates from agricultural fertilizers,
sewage, industrial and packing house wastes, drainage from livestock feeding
areas, farm manures and legumes. Nitrates in large amounts can cause “blue
babies” (methemoglobinemia) in infants less than six months of age. Nitrate
concentration is an important factor to be considered in livestock products,
where, in addition to causing methemoglobinemia, it is responsible for many
other problems. Nitrates in conjunction with phosphate stimulate the growth
of algae with all of the related difficulties associated with excessive algae
growth.
U.S. Public Health Service Drinking Water Standards state that 10 ppm
nitrate nitrogen should not be exceeded. To the sanitary and industrial
engineer, concentrations of less than 1 ppm are acceptable.
APPLICATION: This method determines nitrate levels in drinking, surface,
saline waters, domestic and industrial waters.
RANGE: 0.00–3.00 ppm Nitrate Nitrogen
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.
SAMPLE
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.
Smart2 TEST PROCEDURES 1.07 Nitrate-Nitrogen–LR 1/3