The physicochemical quality evaluated by the standard is the value of molecular activity of hydrogen ions expressed by its pH exponent.
The certified pH value is traceable to the N.I.S.T. and the national pH measurement standard.
The pH value of standards depends on temperature and the values are shown in the certificate of the standard example.
pH standards examples are distributed in 100 cm3 bottles and 250 cm3 bottles.
pH standards evaluate pH scale and they are designed for the standardization of pH-meters and to check the accuracy of pH-electrodes.
pH STANDARDS LIST
| LP | Type No. |
Standard name |
pH Value (25 °C) |
Expanded Uncertainty (k=2) |
Period of validity(months) |
| 1. | BLS 099.010 | TETRO-XALATE | 1,68 | 0,01 | 12 |
| 2. | BLS 099.030 | CITRATE | 3,78 | 0,01 | 12 |
| 3. | BLS 099.040 | PHTHALATE | 4,01 | 0,01 | 12 |
| 4. | BLS 099.060 | PHOSPHATE (1:1) |
6,86 | 0,01 | 12 |
| 5. | BLS 099.070 | PHOSPHATE (1:1.37) |
7,00 | 0,01 | 12 |
| 6. | BLS 099.071 | PHOSPHATE (1:3.5) |
7,41 | 0,01 | 12 |
| 7. | BLS 099.090 | BORATE | 9,18 | 0,02 | 6 |
| 8. | BLS 099.100 | CARBONATE | 10,01 | 0,02 | 6 |
| 9. | BLS 099.120 | CALCIUMATE | 12,4 | 0,1 | 6 |
