This Performance Evaluation Standard is supplied in 2 bottles (Alpha and Beta) in the form of a concentrate prepared by weight and does not require digestion. Dilute both bottles to 1L before use.
Typical values:
Parameter | Unit | Consensus Value | Confidence Interval | Tolerance Interval |
Conductivity @ 25C | uS/cm | 270 | 267 - 273 | 240 - 300 |
Total Hardness (as CaCO3) | mg/l | 12 | 11.5 - 12.4 | 8.2 - 15.7 |
Alkalinity @ pH 4.5 (as CaCO3) | mg/l | 51.8 | 50.9 - 52.6 | 43.8 - 59.8 |
Total Dissolved Solids | mg/l | 143 | 139 - 147 | 114 - 172 |
Calcium (Ca) | mg/l | 2.68 | 2.54 - 2.81 | 1.49 - 3.86 |
Potassium (K) | mg/l | 14.9 | 14.6 - 15.2 | 12.1 - 17.7 |
Magnesium (Mg) | mg/l | 1.29 | 1.26 - 1.32 | 1.03 - 1.56 |
Sodium (Na) | mg/l | 35.8 | 35.3 - 36.3 | 30.9 - 40.7 |
Chloride (Cl-) | mg/l | 19.7 | 19.3 - 20.2 | 15.8 - 23.7 |
Fluoride (F-) | mg/l | 0.609 | 0.589 - 0.629 | 0.415 - 0.803 |
Sulfate (SO42-) | mg/l | 8.24 | 8.05 - 8.43 | 6.4 - 10.08 |
These values were the result of an inter-laboratory study involving 20 international laboratories. Each laboratory was asked to supply analysis data for a specific list of elements. Not all the laboratories supplied data for the different parameters.
Here is a summary of methods used by most of the participating laboratories for the inter-laboratory study:
Ca, K, Mg, Na: ICP-MS, ICP-OES, AAS, IC (Cations), MP-AES
Fluoride: Colorimetric method, IC, ISE
Chloride: IC, Discrete Analyzer, Titration
Sulfate: Colorimetric method, IC
TDS: Gravimetric method
Conductivity: Conductivity meter
Alkalinity: Titration at pH 4.5
Total Hardness: Calculated (with ICP-MS, ICP-OES or MP-AES for Ca & Mg), EDTA titration, Colorimetric method
- Performance Evaluation Standard
- Minerals