For the calibration of pH-testers and pH-meters. These standards are made from analytical grade materials.
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Buffer pH = 4.01Potassium phthalate buffer according to NIST, colour coded red, pH = 4.01 @ 25°C.
Buffer pH = 6.86Phosphate buffer according to NIST, colour coded yellow, pH = 6.86 @ 25°C.
Buffer pH = 7.00Phosphate buffer, colour coded green, pH = 7.00 @ 25°C.
Buffer pH = 9.18Borate buffer according to NIST, colour coded turquoise, pH = 9.18 @ 25°C.
Buffer pH = 10.01Carbonate buffer according to NIST, colour coded blue, pH = 10.01 @ 25°C.
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pH Values of Standard Buffers as Function of Temperature:
| Temperature | Buffer 4.01 | Buffer 6.86 | Buffer 9.18 | Buffer 10.01 |
|---|---|---|---|---|
| 0°C | 4.003 | 6.984 | 9.464 | 10.317 |
| 5°C | 3.999 | 6.951 | 9.395 | 10.245 |
| 10°C | 3.998 | 6.923 | 9.332 | 10.179 |
| 15°C | 3.999 | 6.900 | 9.276 | 10.118 |
| 20°C | 4.002 | 6.881 | 9.225 | 10.062 |
| 25°C | 4.008 | 6.865 | 9.180 | 10.012 |
| 30°C | 4.015 | 6.853 | 9.139 | 9.966 |
| 35°C | 4.024 | 6.844 | 9.102 | 9.925 |
| 40°C | 4.035 | 6.838 | 9.068 | 9.889 |
| 45°C | 4.047 | 6.834 | 9.038 | 9.856 |
| 50°C | 4.060 | 6.833 | 9.011 | 9.828 |

