pH (Direct or In Solution) Test
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Price
Direct: $25 per analysis
In Solution (10%): $25 per analysis -
Turnaround time 7 – 9 business days
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Rush Available
Technical data sheet
Print- Method description
Either pH Direct (unmodified sample) or pH 10%, where the sample is added to carbon dioxide-free water to form a 10% solution.
The hydrogen ion concentration of the sample is determined by measuring the electrical potential produced by an electrode that responds to hydronium ions. The electrical potential is converted to hydrogen ion concentration expressed as the negative logarithm of its concentration (pH). If dissolution or dispersion of the sample is necessary (a 10% solution), carbon dioxide-free water is used.
- Equipment
pH meter equipped with pH probe
- Method reference
AACC 02-52, AOAC 943.02 and 981.12
- Reportable unit
pH units
- Sample size requirements
Direct: 50-100 mL per analysis
In Solution (10%): 10 g per analysis- Information required by submitter
Generally, the handling of samples intended for pH measurement requires no special effort. If carbonates or bicarbonates are present in a sample, submit the sample in a sealed container with little or no headspace to minimize the possible loss of carbon dioxide to prevent altering the pH of the sample.
Common pH (Direct or In Solution) Test Testing Questions
Medallion Labs uses a pH meter with a probe that contains an electrode. The probe is calibrated and placed into the sample. The electrical potential is produced by the electrode and measured as a concentration of hydrogen ions in the sample ie. pH.
This method (probe) is standard for precisely measuring pH.
The two main methods are the probe (electrical potential/voltage) and the litmus paper method. The litmus paper is a piece of paper that contains various dyes and chemicals that, when dipped into a solution, will change color. The color change is then compared against a chart to get a general idea of the pH. The litmus paper test is very general and is not a precise measurement of pH.
We make every effort to keep our methods and detection limits up to date according to the latest standards and qualifications. If you have any questions regarding the limit of detection/quantification or method references, please contact our Customer Service team at 1-800-245-5615.
Our standard turnaround time is 10 business days for most assays. There are some assays that require a longer turnaround time. We also offer a RUSH service that is half the time of the standard turnaround time of the assay at double the cost of the assay. A few assays that we provide cannot be rushed due to the nature of the test. Please check the specific assay you are interested in regarding the ability to RUSH the turnaround time.
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