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201.1 - pH Calibration (powder form)

These SRMs are used to prepare solutions of known hydrogen ion activity to calibrate commercial pH instruments. SRMs 186g and 191d are each certified for use as an admixture only. SRM 186g (186-I-g and 186-II-g) may be used to prepare solutions with a pH of 6. 8640 at 25oC, or physiological buffer solutions with a pH of 7.4157 at 25oC.

PLEASE NOTE: The tables are presented to facilitate comparisons among a family of materials to help customers select the best SRM for their needs. For specific values and uncertainties, the certificate is the only official source.


- Certified values are normal font
- Reference values are italicized
- Values in parentheses are for information only


Detail - Detail    Certificate - Certificate    Report of Investigation - Report of Investigation    MSDS - MSDS    Data Files - Data Files    Questionaire - Questionnaire


  SRM Description Unit Size     pH(S) Values at 25 °C
Detail Certificate MSDS 185i
Now Selling
Potassium Hydrogen Phthalate, pH Standard 60 g   4.005
Detail Certificate MSDS 186g
Now Selling
pH Standards
Potassium Dihydrogen Phosphate (186-I-g)
Disodium Hydrogen Phosphate (186-II-g)
set   see text above
Detail Certificate MSDS 187f
Now Selling
Sodium Tetraborate Decahydrate (Borax) pH Standard 30 g   9.195
Detail Certificate MSDS 188
Now Selling
Potassium Hydrogen Tartrate (pH Standard)
60 g   3.557
Detail Certificate MSDS 189c
Now Selling
Potassium Tetroxalate Dihydrate pH Standard 65 g   1.677
Detail Certificate MSDS 191d
Now Selling
pH Standard
Sodium Bicarbonate (191d-I)
Sodium Carbonate (191d-II)
1 bottle x25g;1bottlex30g   10.014
Detail Certificate MSDS 2193a
Out of Stock
Calcium Carbonate pH Standard [used as saturated Ca(OH)2 solution]
30 g   12.469