YSI ProDSS - Manual (Page 49)

47
Calibration
Preparing chloride standards
The following recipes are provided for preparation of 10 and 1000 mg/L chloride reagents. Nitrate and Ammonium
standards can be purchased from YSI or other laboratory supply companies.
WARNING: Some of the chemicals required for these solutions could be hazardous under some conditions. It
is the responsibility of the user to obtain and study the MSDS for each chemical and to follow the
required instructions with regard to handling and disposal of these chemicals.
You will need:
• Solid sodium chloride or a certified 1000 mg/L chloride solution from a supplier
• Magnesium sulfate
• High-purity water
• A good quality analytical balance
• 1000 mL volumetric flask
• An accurate 10 mL measuring devices
• And 1000 mL glass or plastic storage vessels.
1000 mg/L Standard
1. Accurately weigh 1.655 grams of anhydrous sodium chloride and transfer into a 1000 mL volumetric flask.
2. Add 0.5 grams of anhydrous magnesium sulfate to the flask.
3. Add 500 mL of water to the flask, swirl to dissolve all of the reagents, then dilute to the volumetric mark with
water.
4. Mix well by repeated inversion, then transfer the 1000 mg/L standard to a storage bottle.
5. Rinse the flask extensively with water prior to its use in the preparation of the 10 mg/L standard. Alternatively,
simply add 0.5 grams of magnesium sulfate to a liter of a 1000 mg/L chloride standard from a certified supplier.
10 mg/L Standard
1. Accurately measure 10 mL of the above 1000 mg/L standard solution into a 1000 mL volumetric flask.
2. Add 0.5 grams of anhydrous magnesium sulfate to the flask.
3. Add 500 mL of water, swirl to dissolve the solid reagents, then dilute to the volumetric mark with water.
4. Mix well by repeated inversion, then transfer the 10 mg/L standard to a storage bottle.
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