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Field-ready instruments provide a range of valuable features that complement many uses
After an 11-hour flight from Houston to Rio de Janeiro, a cab ride from the airport to Copacabana, and a long check-in line at the hotel, I stared out the window of my 10th floor room to the beach. Eyes bleary with jetlag, I tumbled backward onto my bed when a huge shadow swooped in front of me. Jumping up nearly as fast as I fell, I pressed close to the window to look high in the sky, where I saw dozens, maybe hundreds, of big fork-tailed birds circling all over. They were magnificent frigatebirds, which have a wingspan of more than 2 meters. A cool sighting, indeed, but it doesn’t sound like pH, until it connects to Carlos Valle of the Universidad San Francisco de Quito in Ecuador.
Valle and his colleagues studied the blood chemistry of great frigatebirds—relatives of the magnificent ones, but truly just as “magnificent”—in the Galápagos National Park.1 To do that, they made portable pH measurements, and more, of the blood. The researchers wrote: “The more we know about the vital parameters of healthy animals, the better our ability to monitor and make changes, if necessary, to human practices and actions. This health assessment expands the foundation for future work in this species and other Galápagos seabirds.” And that depends, in part, on taking pH meters to the field.
Instead of a portable instrument, though, a probe attached to a ring stand and a cable connected to a benchtop instrument come to mind for many scientists when thinking about measuring pH. But many applications could use a way to easily do the same measurements in the field. That requires a portable pH meter, and there are plenty to consider. Being able to carry the device into the field, though, isn’t enough. Specific features can make a pH meter even more at home outside the lab. Let’s find out what those features are.
Features for the field
Titration product manager Lori Spafford of Metrohm USA (Riverview, FL) says that her company “has made investments to modernize the way pH measurements are made in the field.” As she notes, “The color display screen helps improve visibility of the data displayed when working in bright environments.” To help scientists track the use of the meter in the field, Spafford points out that: “Metrohm pH meters have intelligent sensors that are automatically recognized to ensure that calibration data is traceable.”
Many field projects benefit from a portable pH meter. (Image courtesy of Metrohm USA.)Keeping all of the data in the field can also be a challenge. So, it’s worth finding a device designed for that. “The new Metrohm pH meters can log 10,000 complete datasets, which is 2 to 5 times more than traditional pH meters,” Spafford explains. “This means that the analyst can now collect more measurements with fewer interruptions while working in the field.”
When asked about the latest advances in portable pH meters from Thermo Fisher Scientific (Waltham, MA), director of product management Sean Carey says, “In 2017, Thermo Fisher Scientific launched the Elite Series of Waterproof Pocket Testers. … This series improved on previous models of pocket testers by including simultaneous display of pH, conductivity/total dissolved solids/salinity, oxygen reduction potential measurements with temperature.”
Figure 2 – Thermo Fisher Scientific’s Elite Series of Waterproof Pocket Testers analyze a sample’s pH and more. (Image courtesy of Thermo Fisher Scientific.)The designers at Thermo Fisher also added other advances in this series of pH meters. As Carey notes, “Other improvements include simple one-push calibration, waterproof IP67 rating, and long battery life with just 4 AAA batteries.”
When asked how these instruments change pH meters, Carey says, “These improvements make the Elite series of pocket testers ideally suited for field-based measurements.” In describing the process of using one of these meters, Carey says, “It is simple to calibrate and measures samples quickly.”
Overall, Thermo Fisher developed these instruments to meet just the criteria that a scientist or technician needs in the field. “The waterproof IP67 rating makes it ideal for working in wet-environment applications, such as hydroponics, food and beverage, environmental, drinking water, wastewater, agriculture, aquaculture and aquariums, pools and spas, education, and industrial—for example, cooling towers.”
Other options
More pH meters that can go into the field are also available. For instance, Mettler Toledo (Columbus, OH) makes a wide range of portable pH meters. The FiveGo F2 Portable pH/mV Meter has as a “robust and waterproof design” that provides “reliable, high-quality pH/mV, conductivity, or dissolved oxygen measurements with a simple click at a reasonable price.” It covers a pH range of 0–14 with 0.01 resolution.
To move up, users should explore Mettler Toledo’s Seven2Go series. As the company states: “The Seven2Go portables are engineered to provide users with fast quality data, one-handed operation, and durability, making them ideally suited for mobile applications in the laboratory, at-line, and outdoors.” For instance, the Seven2G0 S2 portable pH/mV meter covers a pH range of 0–20. For more rugged applications, customers might look at the Seven2Go S8 Professional Portable pH/Ion Meter, which is described as “simple and reliable, attractively designed, and robust.”
Some Mettler Toledo pH meters also allow a selection of other measurement modes. As an example, the SevenGo Duo SG23 pH/Conductivity Meter can measure a pH range of 0–14, plus electrical conductivity, salinity, total dissolved solids, resistance, and more.
Speaking of more, there are many more options of field-worthy pH meters to consider. Maybe one of them will lead more scientists into the field to explore the physiology of frigatebirds. The expanding range of devices to measure pH covers many fields, and the more that can be explored, the more we will learn. And having instruments to take into more remote locations makes all of the difference. Sometimes, simple scientific measurements can return interesting and important information, as long as the data can be collected at the right time and place, wherever that might be.
Reference
- Valle, C.A.; Ulloa, C. et al. Conserv. Physiol. 2018; doi: 10.1093/conphys/coy034/ [Epub ahead of print].
Mike May is a freelance writer and editor living in Texas. He can be reached at [email protected]