Buff Er Solutions; Electrode Storage - GF Signet 276 Differential Series Operating Instructions Manual

Buff er Solutions
Proper handling, storage and use of buff ers is very important on the pH and ORP measurement accuracy. If the buff ers are
contaminated or used improperly, the calibration will be inaccurate and all subsequent measurements will be wrong.
• When calibrating pH electrodes, always use pH buff ers in the range of your sample.
• To achieve an accurate calibration make sure the electrode and the buff er are at the same temperature.
• Buff ers have limited shelf life. Do not use a buff er if the expiration date has passed.
• Never return used buff ers to the buff er bottle. Discard it.
• Do not leave the buff er bottle open (exposed to air).
The atmospheric carbon dioxide lowers the pH of the alkaline buff ers (10.01 pH).
• To avoid contamination, rinse the electrode with distilled or tap water before placing it in the buff er. If necessary, the electrode
might be blotted dry using a lint-free paper towel (e.g. Kimwipes) to remove excess water. Be extra careful not to touch or rub
the surface of the glass. The wiping of the glass can produce a static charge that will interfere with the voltage reading of the
electrode. In addition to this, the hydration gel layer is interrupted.
• Store buff ers at room temperature.
• Signet off ers the following pH buff er solutions, pH 4.01, pH 7.00 and pH 10.01.
• Make fresh buff er solutions just before using. ORP solutions made with quinhydrone are very unstable and may not read
properly after being exposed to air for a prolonged time. These solutions must be discarded after a few hours.
• Dispose of all calibration solutions in accordance with local guidelines and regulations.

Electrode Storage

Proper electrode storage maximizes electrode performance and extends electrode life.
Prior to storage - add 3 mol/L KCl to the electrode storage cap (about half full), and carefully secure the cap onto the electrode tip.
• Store boxed electrodes wet, fl at or upright (electrode tip down) to maximize hydration of the glass surface.
• Store electrodes in stable temperature environment, avoiding freezing conditions (below 0 °C (<33° F) and heat above 100° F).
• Never store the electrode in deionized (DI) water. Use 3 mol/L KCl solution to keep the glass wet when out of the process.
Short term storage (up to 24 hours) - soak the electrode tip in either pH 4.01 buff er or 3 mol/L KCl solution.
• Drying out of the pH sensitive glass and the junction must be avoided (or damage to the electrode will occur).
• Prior to electrode installation, make sure there's a light fi lm of synthetic grease (such as silicone-free grease) applied to the upper
electrode O-ring. If the electrode will be installed into a GF Signet Installation Fitting, then also apply a thin fi lm of synthetic
grease to the lower O-ring.
Long term storage (longer than 24 hrs) - add 3 mol/L KCl solution to the storage cap (about half full) and carefully secure the cap onto
the electrode tip. This will ensure probes are always ready to use.
Signet 275X, 276X, 2777X Series pH and ORP Electrodes 9