A large range of industries employ pH meters to help run their business. pH meters are used to measure the alkalinity or acidity of a particular substance and are widely used to maintain health and safety standards in products and produce.
Did you know that pH is the second most-tested parameter after temperature? pH testing requires the use of sensitive equipment, and a lot can go wrong. Here’s what you need to know about testing pH.
pH (Potential of Hydrogen) is measured on a scale of 0-14, with 7 meaning ‘neutral’. Tap water and milk are good examples of a neutral liquid. On the lower side of the pH scale (1-6), the measurement is considered ‘acidic’ – types of acidic solutions include lemon juice, cola drinks and hydrochloric acid. 8+ is measured as ‘alkaline’, and includes substances such as ammonia, sodium hydroxide, and bicarbonate soda.
When measuring pH, the three key things to keep in mind are:
- You’re measuring tiny concentrations, so pH electrodes are sensitive, and require good maintenance.
- pH readings are affected by temperature, so this needs to be taken into account when carrying out a measurement.
- pH is a logarithmic scale, meaning that as a pH reading increases, hydrogen ions increase on an even larger scale with each higher measurement. This is why small differences in readings can be much more significant than they may seem.
pH meters contain electrodes that typically need to be replaced annually. When you’re looking for a pH electrode, consider the type and shape of the glass, the junction material, and the body material.
Glass
The glass of a pH electrode is important when applied to specific temperatures, and the type of glass can detect pH levels within a slightly different range. The shape of the glass tip (the ‘bulb’) differs depending on the type of product it will be applied to. A spherical tip works best with liquid solutions, a conical tip is a better option for semi-solid products such as cheese or emulsions, and a flat tip would be our recommendation for direct application to a surface such as skin or paper.
Junction
There are four types of junction: ceramic, PTFE, cloth and open. Each offers different levels of chemical resistance and general durability, making each one suitable for different sets of industries.
Body Material
The body of an electrode can be made of many different materials that will affect the accuracy of a reading when applied to different types of solutions or exposed to different temperatures. The frequency of use also affects the body material of choice.
Glass body electrodes are generally suitable for any type of lab work, as glass is generally chemical-resistant and is easy to clean. PEI (polyetherimide) plastic is highly resistant to aggressive chemicals and are ideal for environmental and industrial applications. PVDF (polyvinylidene fluoride) is a great choice for a wide variety of cleaning chemicals and solvents and is highly resistant to abrasion and fungal growth. Stainless steel is robust and is generally used for the harshest applications.
Different Types Of pH Meters
Pocket meters, bench meters, specialist meters, and food and drink meters are just a few of the many types of pH meters available on the market. Prices range from as little as £515, all the way up to the highest-end cost of £2,590.85.
When choosing a meter that’s right for you and your business uses, it’s important to balance cost with functionality. If you’d like to speak to an adviser on the most appropriate pH meter for you, please contact us to speak to a member of our team.
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