LaMotte COD Plus Colorimeter 1922-EX2 - Manual (Page 118)

SULFATE - HIGH RANGE
BARIUM CHLORIDE METHOD • CODE 3665-SC
QUANTITY CONTENTS CODE
10 g *Sulfate Reagent
*V-6277-D
1 Spoon, 0.1 g, plastic
0699
*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.
The most common mineral forms of sulfur are iron sulfide, lead sulfide, zinc
sulfide and as calcium sulfate and magnesium sulfate. In most fresh waters the
sulfate ion is the second or third most abundant anion, being exceeded only by
bicarbonate and, in some cases, silicate. Sulfur, in the form of sulfate, is
considered an important nutrient element. Mineral springs are rich in sulfate
and feed appreciable quantities of this compound to the watershed. Acid mine
water drainage is a form of pollution which may contribute extremely large
amounts of sulfate content to natural waters. Other sources of sulfate include
waste material from pulp mills, steel mills, food processing operations and
municipal wastes. Many bacteria obtain sulfur from sulfate for the synthesis of
amino acids. In lakes and streams low in oxygen, this process of sulfate
reduction causes the production of hydrogen sulfide, with its characteristic
offensive odor. Calcium sulfate and magnesium sulfate contribute significantly
to the hardness of water. Under natural conditions, the quantities ordinarily to
be expected in lakes are between 3 and 30 parts per million.
APPLICATION:
Drinking and surface waters, domestic and industrial wastes.
RANGE: 0 – 100 ppm Sulfate
METHOD: Sulfate ion is precipitated in an acid medium with barium
chloride to form a barium sulfate suspension in proportion to
the amount of sulfate present.
SAMPLE
HANDLING &
PRESERVATION: Sulfate samples may be preserved by refrigeration at 4°C up
to 7 days in glass or plastic containers without any change in
concentration.
INTERFERENCE: Suspended matter and color interference may be removed by
a filtration step. Silica in excess of 500 mg/L will interfere.
Check for stray light interference (see page 17).
COD PLUS TEST PROCEDURES 6/02 SULFATE - HIGH RANGE 1/2