LaMotte COD Plus Colorimeter 1922-EX2 - Manual (Page 108)

PHOSPHATE - HIGH RANGE
VANADOMOLYBDOPHOSPHORIC ACID METHOD
CODE 3655-SC
QUANTITY CONTENTS CODE
60 mL *VM Phosphate Reagent
*4410-H
1 Pipet, 1.0 mL, plastic
0354
*WARNING: Reagents marked with a * are considered hazardous substances. Material
Safety Data Sheets (MSDS) are supplied for these reagents. For your safety, read label
and accompanying MSDS before using.
Phosphate treatments in boiler and cooling water and other industrial water
systems are run at levels up to 100 ppm orthophosphate. These high levels
permit the use of a simpler, high range test.
APPLICATION:
Boiler, cooling, and industrial water.
RANGE: 0.0 – 70.0 ppm Phosphate
METHOD: Orthophosphate reacts in acid conditions with ammonium
vanadomolybdate to form vanadomolybdophosphoric acid.
This yellow color is proportional to the concentration of
orthophosphate and is read colorimetrically.
SAMPLE
HANDLING &
PRESERVATION: If the analysis cannot be performed the same day of
collection, the sample should be preserved by the addition of
2 mL of concentrated sulfuric acid or 40 mg mercuric
chloride per liter and refrigerated at 4°C.
INTERFERENCES: Silica interferes only if the sample is heated. Arsenate,
fluoride, thorium, bismuth, sulfide, thiosulfate, and
thiocyanate cause negative interference.
COD PLUS TEST PROCEDURES 6/02 PHOSPHATE - HIGH RANGE 1/2