Horiba pH Buffer & Standard Solutions

Genuine HORIBA pH buffer and standard solutions for calibrating any HORIBA pH meter or electrode — LAQUAtwin pocket meters, LAQUA 200 and WQ-300 handhelds, LAQUA 1500/2000 and F-70 benchtops, and the U-50 series field sondes. A pH measurement is only as good as the buffer it was calibrated against. Buffers absorb carbon dioxide from the air and drift over time once opened, and alkaline buffers drift fastest — a pH 10 bottle left open on the bench will read low within weeks. Using fresh, in-date buffer is the single most effective way to keep pH data defensible. Two buffer conventions — choose the right one USA / technical series — pH 4.01, 7.00 and 10.01. The convention used across most US laboratories and regulatory programs. NIST / DIN series — pH 4.01, 6.86 and 9.18. Used where NIST-traceable buffer values are specified. Do not mix conventions within one calibration. If your SOP or permit names buffer values, match them exactly. What is available Ready-to-use 500 mL bottles — pH 2, 4, 7, 9 and 10. The standard choice for routine bench and field calibration. Solution sets — three buffers plus KCl reference filling solution in one box, in USA or NIST values. The economical way to equip a new meter. Concentrated solution — pH 4 concentrate, diluted before use to reduce shipping and storage volume. Buffer powders — pH 4, 7 and 9 sachets made up with deionized water as needed. Powders do not drift in storage, so they are ideal for infrequent use, remote sites and long shelf-life stock. Handling for reliable results Pour buffer into a clean beaker and discard it after use — never return used buffer to the bottle Keep bottles tightly capped and out of direct sunlight Rinse the electrode with deionized water between buffers, and blot rather than wipe Calibrate at the temperature of your samples wherever possible Replace alkaline buffers more frequently than acidic ones Related items Conductivity standards, ORP standards, ion standards, ionic strength adjustors, electrode filling solutions and electrode cleaning reagents are all stocked — see the Horiba Parts & Accessories collection. The 4 L pH 4 standard solution is listed with the U-50 Series accessories, and the 60 mL pH calibration set that fits the LAQUA 200 and WQ-300 carrying cases is listed with the WQ-300 sensor accessories. Browse all HORIBA instruments.