INTENDED FOR
Preparation of buffer solutions, reproducing and transmitting values of the activity index of hydrogen ions (pH) in aqueous solutions.
DESCRIPTION OF MEASURING INSTRUMENT
Titration standards represent quantities of chemical substances upon dissolution of which in a certain volume buffer solution – pH working standards are received. рН working standards of 1 category are prepared by diluting the quantity of substance with double-distilled water with specific electrical conductance (SEC) not more than 2·10-4 S/m. рН Working standards of 1st category are prepared in accordance with TC 2642-006-02567567-2010. Titration standards for preparation of buffer solutions – рН working standards of 1st and 2nd categories of СТ-рН.
TECHNICAL CONDITIONS
Titration standards are contained in plastic bottles. The bottle is leakproof and has a screw cap with a protective ring. Titration standards СТ-рН-1 have 8 modifications differing in the composition of the quantity of substance, the concentration of chemicals in the prepared buffer solution and reproducible pH value.
SPHERES OF APPLICATION
Healthcare metrological support, food industry, laboratory research.
| Modifications of titration standards | Name of chemical substances, included in titration standards | Chemical formula of substances | Weight of quantities of chemical substances, g | Weight of quantities of chemical substances, g | рН reproducible value at temperature +25°С |
| ST-рН-1-1 | Potassium tetraoxalate dihydrate | KH3(C2O4)2·2H2O | 12.6100 | 0.05 | 1.646 |
| ST-рН-1-2 | Potassium hydrotartrate | KНC4H4O6 | 9.50 | saturated at temperature +25°С | 3.557 |
| ST-рН-1-3 | Potassium hydrogenphthalate | KНC8H4O4 | 10.1200 | 0.05 | 4.005 |
| ST-рН-1-4 | Potassium phosphate monosubstituted
Sodium phosphate twice-substituted |
KH2PO4 Na2HPO4 |
3.3880
3.5330 |
0.025
0.025 |
6.865 |
| ST-рН-1-5 | Potassium phosphate monosubstituted
Sodium phosphate twice-substituted |
KH2PO4 Na2HPO4 |
1.1790
4,3030 |
0.0087
0,0304 |
7.413 |
| ST-рН-1-6 | Sodium tetraborate decahydrate | Na2B4O7·10H2O | 3.8064 | 0.01 | 9.180 |
| ST-рН-1-7 | Sodium carbonate
Sodium carbonate acid |
Na2CO3
NaHCO3 |
2.6428
2.0947 |
0.025
0.025 |
10.012 |
| ST-рН-1-8 | Calcium hydroxide | Са(OH)2 | 1.75 | saturated at temperature +20°С | 12.43 |
