PHYLLIDIA VARICOSA

pH Calibration Buffers

NIST-traceable pH buffer standards at pH 4.0, 7.0, and 10.0 for calibrating pH meters and electrodes. Color-coded bottles with certificates of analysis.

4.0 / 7.0 / 10.0

pH Values

NIST

Traceable

± 0.01

pH Accuracy

Calibration Buffer, pH 10.0, 2 X 500mL

SKU: PHB-10-0100

Calibration Buffer, pH 4.0, 2 X 500mL

SKU: PHB-04-0100

Calibration Buffer, pH 7.0, 2 X 500mL

SKU: PHB-07-0100

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Accurate pH Starts with Proper Calibration

pH meters drift over time as electrodes age and reference junctions degrade. Regular calibration with certified buffer standards ensures your measurements remain accurate. Our NIST-traceable buffers are manufactured under ISO 9001 controls with lot-specific certificates of analysis documenting actual pH values at 25°C.

For most lab work, a two-point calibration using pH 7.0 and the buffer closest to your sample pH (4.0 for acidic, 10.0 for basic) is sufficient. Use a three-point calibration (pH 4.0, 7.0, 10.0) when measuring across a wide pH range or when regulatory compliance requires it. Always calibrate at the temperature of your measurements.

Never pour used buffer back into the stock bottle. Decant a small volume into a clean beaker for calibration. Contaminated buffers will give inaccurate readings and corrupt the entire bottle. Replace open buffers every 3–6 months, or sooner if you notice drift during verification checks.

FREQUENTLY ASKED

pH Buffer FAQ

Calibrate daily for critical measurements (QC, regulatory work) or at minimum before each use session. If the meter sits idle for more than a few hours between readings, recalibrate. New electrodes and glass electrodes older than 12 months should be calibrated more frequently.

Color coding (typically red = pH 4.0, yellow/green = pH 7.0, blue = pH 10.0) prevents accidental use of the wrong standard during calibration. This is an industry convention that reduces procedural errors, especially in multi-user labs.

NIST-traceable means the buffer’s pH value is calibrated against reference standards maintained by the National Institute of Standards and Technology. This unbroken chain of measurement comparisons ensures accuracy and is required for GLP, GMP, and ISO-accredited laboratories.

We stock the three standard calibration points (pH 4.0, 7.0, 10.0). Intermediate values (pH 1.68, 6.86, 9.18, 12.45) are available on request for specialized applications. Contact us for availability and lead times.

Setting up a QC calibration program?

We offer pH buffer sets and scheduled replenishment plans for labs that need consistent supply with certificates of analysis.