LaMotte SMART3 Colorimeter User Manual

Page 216

APPLICATION:

swimming pools, drinking water, surface and saline

waters

RANGE:

0.00 – 80.0 ppm nitrate

MDL:

2 ppm

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.

NITRATE, UDV

SMART3 Test Procedures 11,11

Test P

rocedures