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Potassium Chloride 3 M, pH Electrode Solution, 4 oz

$28.67
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SKU: ZP1414-04
California prop 65
Description
  • What it is. This potassium chloride solution is a 3 molar (3 M) KCl electrolyte for pH electrodes, supplied in a 4 oz size. It is used to refill refillable reference electrodes and to store pH electrodes so the glass membrane stays hydrated between measurements.
  • What 3 M means. Each liter contains 3 moles of potassium chloride, about 223.7 g (calculated from 74.55 g/mol). That concentration matches the reference electrolyte used in many silver/silver chloride reference electrodes.
  • Electrode storage. When a pH electrode is not in use, its glass tip should stay wet. Drying out the sensing membrane slows response time and shortens electrode life. Storing the tip in 3 M KCl keeps the membrane hydrated and the reference junction in equilibrium.
  • Refilling reference electrodes. Refillable electrodes lose electrolyte through the junction over time. Topping up with the correct KCl concentration keeps the reference potential stable. Check the electrode manufacturer's instructions, since some designs call for KCl saturated with silver chloride or a different concentration.
  • Why not store in water. Storing a pH electrode in deionized water draws ions out of the reference electrolyte and the glass membrane, which can slow response and cause drift. KCl solution avoids that loss.
  • Size for the bench. The 4 oz size suits individual meters and small labs, providing enough solution for regular storage boot refills and electrode top-ups.
  • After storage. Before measuring, rinse the electrode with deionized water, blot it gently, and calibrate with fresh buffers. If response is slow after long storage, soaking the tip in 3 M KCl for a period often restores performance.
  • Chemical identity. Potassium chloride (CAS 7447-40-7, KCl, 74.55 g/mol) is a neutral salt that is highly soluble in water. At 3 M, the solution is close to neutral and low hazard in normal use.
  • Related products. Calibrate after refilling or storage with fresh buffers such as Lab Pro's Buffer Solution pH 7, Yellow, Buffer Solution pH 4, Red, and Buffer Solution pH 10, Blue.

Technical Specifications

Chemical Name Potassium chloride, aqueous solution
CAS Numbers 7447-40-7 (potassium chloride); 7732-18-5 (water)
EC Number (KCl) 231-211-8
Synonyms KCl solution, sylvite (mineral), muriate of potash
Formula (active) KCl
Molecular Weight (active) 74.55 g/mol
Concentration 3 M (3 mol/L)
KCl Content About 223.7 g/L (calculated)
Use pH electrode storage and reference electrolyte filling
AgCl Saturation Not stated; confirm with Lab Pro
Appearance Clear, colorless liquid
Hazard Profile Low hazard (confirm on SDS)
Package Size 4 oz

Applications / Common Uses

  • Electrode storage: Keeps pH glass membranes hydrated.
  • Reference electrolyte: Refills refillable Ag/AgCl reference electrodes.
  • Storage boot refills: Fills electrode storage boots.
  • Junction maintenance: Keeps reference junctions in equilibrium.
  • Meter maintenance: Supports routine pH meter upkeep.

Storage, Handling & Shipping

Store tightly closed at room temperature. Keep the solution free of contamination by pouring small amounts for use and never returning used solution to the container. Evaporation can raise concentration and cause crystals to form around openings.

  • Incompatible materials: Strong oxidizers.
  • Personal protection: Safety glasses and gloves as standard practice.
  • Spill response: Wipe up and rinse the area with water.
  • First aid: Eyes: rinse with water if irritation occurs.
  • GHS signal word: Not classified
  • DOT / shipping: Not regulated.

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FAQs

What is 3 M KCl used for with pH electrodes?

It is used to store pH electrodes so the glass membrane stays hydrated, and to refill refillable reference electrodes whose electrolyte has dropped. Both keep the electrode responding quickly and holding a stable reference potential, which improves calibration and measurement accuracy. Use it with every refillable electrode that specifies 3 M KCl.

Why shouldn't pH electrodes be stored in water?

Deionized water pulls ions out of the reference electrolyte and the glass membrane by diffusion, which can slow electrode response and cause drift. Potassium chloride solution keeps the junction and membrane in equilibrium, so the electrode is ready to calibrate and measure. Rinse with water only between readings.

Does my electrode need KCl saturated with silver chloride?

Some silver/silver chloride reference electrodes call for 3 M KCl saturated with silver chloride to prevent silver chloride from dissolving off the reference element. Check your electrode manual, and confirm with Lab Pro whether this solution is AgCl-saturated before using it as a refill. Check before refilling.

How often should I refill the reference electrolyte?

Check the electrolyte level regularly and top it up when it drops noticeably below the fill hole, following the electrode manufacturer's guidance. Open the fill port during measurement if your electrode design requires it, so electrolyte flows steadily through the junction. Close the port again when you finish measuring.

How much potassium chloride is in a 3 M solution?

A 3 M solution contains 3 moles of potassium chloride per liter, which is about 223.7 g per liter, calculated from a molecular weight of 74.55 g/mol. Comparable commercial 3 M electrode solutions list about 224 g of KCl per liter. That supports routine use.