LaMotte STH Series - Manual (Page 28)

Soil pH Test - Sensitive short range pH indicators are used to
measure the pH of a distilled water soil extract. Barium Sulfate is
used to accelerate settling of the soil water mixture.
Calcium Test - *Calcium Test Solution (5108PS) is sodium
oxalate, which reacts with calcium to form a precipitate of
Calcium Oxalate.
Ammonia Nitrogen Test - *Ammonia Nitrogen Test
Solution (5103PS) is Nessler’s Reagent.
Magnesium Test - The dye Titian Yellow, *Magnesium Test
Solution 1 (5140), is absorbed on the precipitated magnesium
hydroxide which is formed when *Magnesium and Manganese
Test Solution #2 (5145PS), sodium hydroxide is added. The
degree of color in the test reaction depends on the amount of
precipitate formed.
Manganese Test - Manganeseis oxidized by the Manganese
Periodate Reagent (6311) to form permanganate.
Aluminum Test - *Aluminum Test Solution (5101) is an
alcoholic solution of hematein.
Nitrite Nitrogen Test - *Nitrite Nitrogen Reagent 1 (5151PS)
is hydrochloric acid. *Nitrite Nitrogen Reagent 2 (5152PS) is
Lombard’s Solution, which consists of sulfanilic acid, ammonium
chloride, and phenol. *Nitrite Nitrogen Reagent 3 (5153PS) is
sodium hydroxide. A yellow dye is formed when nitrite is present.
Ferric Iron Test - *Ferric Iron Test Solution (5116PS) is
potassium thiocyanate, which reacts with iron to give the color
ferric thiocyanate.
Sulfate Test - *Sulfate Test Solution (5171) is barium chloride,
which reacts with sulfate to form the precipitate, barium sulfate.
Chloride Test - Deionized water is used as the extracting
solution. *Chloride Test Solution (5111) is silver nitrate, which
reacts to form the precipitate, silver chloride.
26