EPA-NERL: 150.1: pH in Water by Electrometric Method
|
Official Method Name
|
pH, Electrometric Method |
|---|---|
|
Current Revision
| Issued 1971; Editorial Revision 1978 and 1982 |
|
Media
|
WATER |
|
Instrumentation
|
pH Meter |
|
Method Subcategory
|
Inorganic |
|
Method Source
|
|
|
Citation
|
|
|
Brief Method Summary
|
The pH of a sample is determined electrometrically using either a glass electrode in combination with a reference potential or a combination electrode. |
|
Scope and Application
|
This method determines the pH of drinking, surface and saline water; and domestic and industrial wastes and acid rain (atmospheric deposition). |
|
Applicable Concentration Range
|
None given. |
|
Interferences
|
(1) Sodium error may bias results at pH > 10 unless a "low sodium error" electrode is used. (2) Coatings of oily material can impair electrode. (3) Temperature effects. |
|
Quality Control Requirements
|
not included |
|
Sample Handling
|
Collect a volume of 25 mL in glass or plastic bottles. No preservation is required. The samples should be analyzed as soon as possible after collection, preferably in the field. |
|
Maximum Holding Time
|
ASAP |
|
Relative Cost
|
Less than $50 |
|
Sample Preparation Methods
|
