Why do I see moisture inside the bellows of my sensor insertion assembly?

Glass pH sensors have a porous ceramic junction that allows the reference electrolyte (a KCl solution) to contact the measured solution. During extended dry storage, the reference electrolyte may slowly leak from the junction by design, forming a visible drop of liquid inside the bellows. This electrolyte is non-cytotoxic (data…

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Dissolved Oxygen Sensor Life Expectancy

How long should a DO sensor last in storage? OxyProbes can be stored for several months from date of shipment with no appreciable change in their performance or expected service life. After a few months, the sensors are still good but they will probably need to have the membrane removed…

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How do I change an OxyProbe II Membrane Cartridge?

There are two distinct types of 12 mm DO sensor cartridges: one for the traditional style sensor (for example, OxyProbe D140) and one for the newer style OxyProbe II sensors. Please make sure you received the right membrane cartridge for your particular sensor design. The old and new membranes are…

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How do I change a membrane cartridge on a 19mm and 25mm Probe?

Step 1 While holding the membrane cartridge upright (with opening up) in one hand, carefully pour the electrolyte from the bottle into the cartridge until approximately 75% full. Remove any entrapped air bubbles by tapping on the side of the membrane housing. Try not to spill any of the electrolyte…

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How do I change a membrane cartridge on a 12mm DO Probe?

Step 1 While holding the membrane cartridge upright (with opening up) in one hand, carefully pour the electrolyte solution from the bottle into the cartridge until level is approximately 1/8″ (3 mm) from the top edge of the cartridge. Remove any entrapped air bubbles by gently tapping on the side…

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How do I test my pH electrode?

pH Electrode Test Procedure The purpose of this test is to determine if a pH electrode is functioning within acceptable limits. The asymmetry potential (A.P) and slope (efficiency) can be used as guidelines to judge an electrode’s performance. Typically an electrode is replaced when the A.P is greater than ±20…

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TRIS Buffers – What electrodes can I use?

TRIS buffers are used by biochemists to control pH in the physiological range (about 7 to 8 pH) because phosphates cause undesirable side reactions with the biological substances in their test samples. However, when pH measurements are to be made on these solutions, another type of “undesirable side reaction”, involving…

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Do you have a datasheet for FermProbe Wetted Materials?

The FermProbe Double Junction Reference System All FermProbes have two built-in electrolyte chambers that act to protect and isolate the sensitive inner AgCl reference half-cell. This “double junction”, dual-chamber design effectively prevents the most common failure modes of pH electrodes in biopharmaceutical applications. Only the inner, smaller chamber contains silver…

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