- What it is. This pH 12 buffer solution is a high-alkaline pH standard used to calibrate pH meters and electrodes for strongly basic samples. It is supplied in a 1-pint size for labs that measure above the range covered by standard pH 10 buffer.
- When pH 12 calibration is needed. Routine calibration with pH 4, 7, and 10 covers most samples. When samples run above pH 10, such as caustic cleaning solutions, alkaline process streams, or strongly basic wastewater, a pH 12 buffer extends the calibration range so readings are interpolated rather than extrapolated beyond the last calibration point.
- How a buffer holds its pH. A buffer contains a weak acid and its conjugate base, or a weak base and its conjugate acid, in balanced amounts. When small amounts of acid or base enter the solution, one partner neutralizes them, so the pH barely moves. That resistance to change is what makes a buffer a reliable reference point for calibration, unlike plain water.
- The high-pH challenge. At high pH, glass electrodes can respond to sodium and other alkali ions in addition to hydrogen ions, an effect known as alkaline or sodium error, which makes readings lower than the true value. Calibrating near the measurement range with a pH 12 buffer helps reveal and reduce this error, and many labs use electrodes designed for high-pH work.
- Highly sensitive to carbon dioxide. Strongly alkaline buffers absorb carbon dioxide from the air faster than pH 10 buffers, lowering the pH over time. Keep the container tightly closed, pour out only what you need right before calibrating, and discard used buffer immediately.
- Temperature matters. Buffer pH shifts slightly with temperature, so the stated value applies at 25 °C. Calibrate at the same temperature as your samples, use automatic temperature compensation, and apply the temperature-correction values supplied with the buffer when available.
- Calibration best practice. Rinse the electrode with deionized water and blot it gently between buffers, immerse it in a fresh portion of buffer in a clean beaker, stir gently, and wait for a stable reading before accepting each point. Calibrate before each day's measurements, or more often as the method requires, and record the meter-reported slope to track electrode health.
- Where it is used. Use pH 12 buffer in chemical manufacturing, metal finishing and cleaning operations, industrial wastewater treatment, pulp and paper, and research labs that work with strong bases. It pairs with Lab Pro's Buffer Solution pH 10, Blue and Buffer Solution pH 7, Yellow for calibration across the alkaline range.
Technical Specifications
| Product | pH 12 buffer solution |
| Nominal pH | 12 at 25 °C |
| Use | High-alkaline pH meter calibration |
| Package Size | 1 pint |
Applications / Common Uses
- High-pH calibration: Extends meter calibration above pH 10.
- Caustic solution testing: Brackets measurements of strong cleaning and etching solutions.
- Industrial wastewater: Supports accurate readings of strongly alkaline effluent.
- Electrode performance checks: Reveals alkaline error in glass electrodes.
- Process QC: Verifies in-line meters used in high-pH processes.
Storage, Handling & Shipping
Store pH 12 buffer tightly closed at room temperature, protected from light and freezing. Because strongly alkaline solutions absorb carbon dioxide rapidly, open the container only when dispensing and use opened stock within the period stated on the label or certificate.
- Storage temperature: Store at room temperature and protect from light and freezing.
- Contamination control: Pour the amount needed into a clean beaker; never return used buffer to stock or dip an electrode into the stock container.
- Shelf life: Use before the expiration date on the label; once opened, use within the period stated on the certificate or label.
- Personal protection: Wear safety glasses and gloves; strongly alkaline solutions can irritate skin and eyes.
- Rinsing: Rinse electrodes with deionized water between buffers to prevent carryover.
Related Categories & Services
- Shop pH Buffers for related products in this category.
- Explore Buffers by Lab Pro and Buffers, Standards & Solutions.
- Vendor Managed Inventory (VMI) Program: Lab Pro can stock, track, and replenish this item on site so it never runs out. Contact info@labproinc.com or 888-452-2776 to set up a VMI assessment.
