Preparation ratio of pH meter pH electrode standard buffer solution
A pH electrode, also known as a pH probe or pH sensor, is the part of a pH meter that comes into contact with the measured substance and is used to measure the electrode potential.
The pH meter and pH electrodes need to be calibrated with standard buffer solution together, and when configuring the standard buffer material, a standard buffer ratio needs to be prepared to ensure measurement accuracy. Next, let's understand the proportion of standard buffer solution for pH meter pH electrode calibration:
(1) Precisely weigh 12.61g of potassium dihydrogen oxalate [KH3 (C2O4) 2 · 2H2O] dried at 54 ± 3 ℃ for 4-5 hours in potassium dihydrogen oxalate standard buffer, add water to dissolve and dilute to 1000ml.
(2) Precisely weigh 10.12g of potassium hydrogen phthalate [KHC8H4O4] standard buffer solution dried at 115 ± 5 ℃ for 2-3 hours, add water to dissolve and dilute to 1000ml.
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3) Precisely weigh 3.533g of anhydrous disodium hydrogen phosphate and 3.387g of potassium dihydrogen phosphate, dried at 115 ± 5 ℃ for 2-3 hours, with phosphate standard buffer solution (pH 6.8). Dissolve with water and dilute to 1000ml.
(4) Precisely weigh 4.303g of anhydrous disodium hydrogen phosphate and 1.179g of potassium dihydrogen phosphate, dried at 115 ± 5 ℃ for 2-3 hours, with phosphate standard buffer solution (pH 7.4). Dissolve with water and dilute to 1000ml.
Precisely weigh 3.80g of borax [Na2B4O7 · 10H2O] with quasi buffer solution (note: to avoid weathering), dissolve with water and dilute to 1000ml, place in a polyethylene plastic bottle, seal tightly, and avoid contact with carbon dioxide in the air.
