Measuring pH is a necessity in almost every lab. However, many investigators and laboratory personnel often purchase meters without too much thought about the convenience, accuracy, durability, or ease of use. Considering that pH is a critical parameter in chemical, life sciences, biochemical, and pharmaceutical research, choosing a reliable pH meter is crucial and many varieties are available on the market, including those from Mettler Toledo.
The Mettler Toledo Seven Easy pH meter has a pH range from 0 to 14 with a resolution of 0.01, which reads out in large characters on the display. The instrument also offers automatic temperature compensation (ATC), which corrects for the effect of temperatures between -5C and 105C on the electrode reading. An automatic endpoint feature is also claimed to markedly improve reproducibility of pH readings, which will be important if the user requires continual precision. Furthermore, the meter has a convenient integrated interface for data exchange if that feature is desired.
Most features on the Seven Easy pH meter are somewhat standard in comparison to other meters in a similar price range. However, what makes this meter stand out is the buffer recognition system that allows you to pre-program the order in which you want to calibrate. Although this feature makes calibrating less of a hassle, it is not as easy to program the Seven Easy meter for calibration in comparison to others I have used. The advertisements for this meter claim that the programming makes operation as easy as “child’s play”, which I must agree with; however, programming is not as easy as it could be. The manual provided with the meter does not include a quick start guide to programming so if you purchase this meter be ready to spend a bit more time than usual in programming for operation. The manual is easy to follow, but the procedures are lengthier than I would like. Nevertheless, once the programming is preset, the meter is ready to go and is undoubtedly easy to use.
Unlike some of the more expensive meters, the Seven Easy pH meter is made of a lightweight plastic and is not very sturdy. The component parts are separate and easy to move around, but I find this a bit of a hassle and prefer a meter that has a more secure base. The electrode arm on the Seven Easy is a great idea because it allows you to effortlessly support the electrode in solution and move between buffers, washes, and your solution of interest. However, the base of the electrode arm stand on the Seven Easy is not secure enough to allow you to move it from one area to another without firmly fixing the base with your other hand.
Amy Bellmeyer, M.S.
Research Technician
Northwestern University
Division of Pulmonary and Critical Care Medicine