PH meter common standard titers (fixed samples), Zaporizhia region.

The pH-meter uses a common titer standard (fixed channels).
pH meter general application:
Standard titers for pH measurement are glass ampoules and plastic vials with a weighted substance, intended for reproducing the pH scale of aqueous solutions during calibration of pH measurement devices, as well as for controlling the error of the pH measurement method in a liquid medium.
The set contains 6 ampoules with different pH values.
type 1 potassium tetraoxolate dihydrate (КН3(С2О4)2·2Н2О) pH 1.68(//tractor-service.com)
type 2 potassium hydrotartrate (КНС4Н4С6) pH 3.56
type 3 potassium hydrophthalate (КНС8Н4О4) pH 4.01
type 4 potassium dihydrogen phosphate (phosphoric acid monosubstituted) КН2РО4 sodium monohydrophosphate (phosphoric acid disubstituted) Na2НРО4 pH 6.86
type 5 sodium tetraborate 10-water (Na2B4O7·10Н2О) pH 9.18
type 6 calcium hydroxide (Ca(OH)2) pH 12.45