LaMotte SMART Spectro Spectrophotometer - Manual (Page 170)

NITRATE
ZINC REDUCTION • CODE 3689-SC
QUANTITY CONTENTS CODE
50 *Nitrate Spectrophotometic Grade Tablets *3881A-H
1 Tablet Crusher 0175
*WARNING: Reagents marked with a * are considered to be potential health hazards. To view
or print a Material Safety Data Sheet (MSDS) for these reagents see MSDS CD or
www.lamotte.com. To obtain a printed copy, contact LaMotte by e-mail, phone or fax.
Nitrogen is essential for plant growth, but excessive amounts in water supplies
can result in nutrient pollution. Nitrates, in conjunction with phosphate,
stimulate the growth of algae creating water quality problems. 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 and manure. Nitrates in large amounts in drinking
water can cause “blue baby syndrome” (methemoglobenemia) in infants in less
than 6 months of age and other health problems. US Public Health Service
Drinking Water Standards state that 44 ppm nitrate should not be exceeded.
To the sanitary and industrial engineer, concentrations of less than 4 ppm are
acceptable.
APPLICATION: Drinking, surface, and saline waters; domestic and industrial
waters.
RANGE: 0–60 ppm Nitrate
METHOD: Zinc is used to reduce nitrate to nitrite. The nitrite that was
originally present, plus the reduced nitrate, reacts with
chromotropic acid to form a red color in proportion to the
amount of nitrite in the sample.
SAMPLE
HANDLING &
PRESERVATION: Analysis should be made as soon as possible. If analysis
cannot be made within 24 hours, the sample should be
refrigerated at 4°C. When samples must be stored for more
than 24 hours, add 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 interferes at all concentrations. Strong oxidizing and
reducing substances interfere. Low results might be obtained
for samples that contain high concentrations of copper and
iron.
SMART SPECTRO TEST PROCEDURES 04.08 Nitrate-TesTab 1/2