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Calibration
1 mg/L Standard
1.
Accurately measure 10.0 mL of the above 100 mg/L standard solution into a 1000 mL volumetric flask. Add 2.6
g of lithium acetate dihydrate to the flask.
2.
Add approximately 500 mL of distilled or deionized water. Swirl to dissolve the solid reagents and then dilute to
the volumetric mark with water.
3.
Mix well by repeated inversion and then transfer the 1 mg/L standard to a storage bottle.
4.
Add 3 drops of concentrated hydrochloric acid to the bottle, then seal and agitate to assure homogeneity.
Other concentrations can be made by altering the amount of ammonium chloride. All other ingredient concentrations
should remain unchanged.
Nitrate Standards
You will need:
• Solid potassium nitrate or a certified 1000 mg/l NO
3
-N from a supplier
• Magnesium sulfate, high purity water
• A good quality analytical balance
• 1000 mL volumetric flask
• Accurate volumetric measuring devices for 100 mL, 10 mL and 1 mL of solution
• And 1000 mL glass or plastic storage vessels
100 mg/L standard
1.
Accurately weigh 0.7222 g of anhydrous potassium nitrate and transfer quantitatively into a 1000 mL volumetric
flask. Add 1.0 g of anhydrous magnesium sulfate to the flask.
2.
Add approximately 500 mL of water to the flask. Swirl to dissolve all of the reagents, and then dilute to the
volumetric mark with distilled or deionized water.
3.
Mix well by repeated inversion and then transfer the 100 mg/L standard to a storage bottle.
4.
Rinse the flask extensively with water prior to its use in the preparation of the 1 mg/l standard. Alternatively, 100
mL of certified 1000 mg/L NO
3
-N standard can be used in place of the solid potassium nitrate.
1 mg/L standard
1.
Accurately measure 10.0 mL of the above 100 mg/L standard solution into a 1000 mL volumetric flask. Add 1.0
g of anhydrous magnesium sulfate to the flask.
2.
Add approximately 500 mL of distilled or deionized water. Swirl to dissolve the solid reagents, and then dilute
to the volumetric mark with water.
3.
Mix well by repeated inversion and then transfer the 1 mg/L standard to a storage bottle.
Other concentrations can be made by altering the amount of potassium nitrate. All other ingredient concentrations
should remain unchanged.
Ammonium Standards
(continued)
