The capabilities of ion chromatography are essential as hexavalent chromium limits plunge ever lower in the attempt to ensure safe drinking water for all.
After nearly a decade of false starts, questions and legal action, California state has issued a final drinking standard for hexavalent chromium, which will take effect July 2014. The current California law sets 50 parts-per-billion total chromium as the maximum allowable in drinking water, but this amount includes both chromium(III), which is not a carcinogen and necessary in small amounts to human life, and chromium(VI), an atomic relative that has been shown to cause several types of cancers. California’s new law, though, sets the standard for chromium(VI) at 10 parts-per-billion (10 μg/L).
Ion chromatography (IC) has long been at the forefront of chromium detection, and its applications and technology continue to grow as we learn more and more about our environment. Metrohm’s IC guru and Regulatory Affairs Manager Jay Gandhi recently spoke with Chromatography Techniques Editor Michelle Taylor about specific IC applications and what role the technology will play in the future.
MT: How does IC technology ensure the safety of drinking water?
JG: IC technology separates the ions. Ions are suited for any salt in water because they are very soluble. Ions can be negative in charge, known as anions, or positively charged, known as cations. For example, fluoride in drinking water, nitrite/nitrate in water or phosphate in drinking water can be easily monitored using IC. Fluoride is important for dental health, nitrile/nitrate relates to bacteriological presence in the drinking water and phosphate can be either a pollutant or indicator of bad bacteria. This is the anion side of things. If you flip the coin to the cation side, you can monitor total hardness, like calcium and magnesium, in drinking water. You can also monitor ammonia concentration; ammonia is a positively charged nitrogen ion that is linked to bacterial growth.
MT: In what other food and beverage apps has IC proven its worth?
JG: In the food and beverage industry specifically, IC is used with calcium-fortified orange juice. Manufacturers add calcium lactate as an additive to natural orange juice. Both calcium and lactaid can be monitored as cations using IC. If you had a dual-channel IC with an anion and cation channel, you could counterbalance the calcium and lactate acid concentrate. Overdoing calcium would make the orange juice taste like chalk; whereas overdoing calcium lactaid would cause problems for consumers with lactaid intolerance.
The FDA regulates the dosing of these chemicals, which is done directly by humans, to make sure there is no under-or over-dosing. Companies need precise technologies, like IC, to comply with these rules and regulations.
Another very common example is the analysis of any soft drink because it contains phosphoric acid. Using IC, you can monitor the concentration of phosphate to extreme precision. A Coca-Cola plant, for example, processes 10,000 bottles of beverage in about one hour. If they have out-of-specification products and don’t catch it for two hours, that is 20,000 bottles going down the drain, in addition to disposal and lost production costs. So, they need precise instruments to measure as quickly as possible, and that’s the role IC plays.
MT: In what other applications does IC play a valuable role?
JG: IC is a great tool in the pharmaceutical industry. Every drug manufacturer wants to look at impurities; whether they are using source water or source chemicals, they need to look at the impurities. IC plays an important role in monitoring those active pharmaceutical ingredients.
MT: How does the technology keep up with the ever-increasing regulations of the EPA, RoHs, etc.?
JG: Metrohm actively participates in EPA meetings and conferences to see if there are any upcoming regulation changes or need to monitor something else. If IC is a part of the multiple technologies used, we have to develop applications to match and prepare for upcoming regulatory changes.
The prime example here is hexavalent chromium in drinking water. As of July 1, 2014, the state of California will be the first government entity in the world to regulate hexavalent chromium at 10 ppb in drinking water. What is starting in the state of California will propagate to other states, and the federal government will be forced to place a federal regulation on hexavalent chromium in the coming years.
To be prepared in 2014 for this change, Metrohm began collaborating with the EPA in 2010, so it’s been four years of work.
MT: Application-specific systems are growing in popularity. Why are researchers attracted to this type of system?
JG: Application-specific systems are popular because they are a turnkey solution. They are easy to implement and easy to use without having a high-level skill set.
It is all about doing things faster and cheaper now. In industry, it is cheaper to hire someone with two or three years’ experience, even though they may not have the depth of experience. Therefore, they work with one skill set for a while. As an instrument lender, Metrohm has seen that application-specific systems are the best way to cater to these companies and staff.
MT: Everything is being hyphenated these days, and IC is no exception. What are the advantages of IC tandem MS?
JG: Hyphenation is the future. For example, people want to know how much hexavalent chromium is in their food and water. But not all chromium is bad for your body—chromium(III) is a required micro-nutrient that helps burn fat into energy. While that may be good for body fat, you still need to know how much of each chromium species is in anything you digest because of its potential toxicity as chromium(VI). Hyphenated technology allows speciation by IC and low-level detection using sensitive detectors, like mass spectrometry.
Nowadays, companies are merging and allowing open access to their instruments, which allows this hyphenation to be done easily.
MT: What are some technology enhancements we may see from IC in the near future?
JG: Sensitivity and selectivity is the name of the game—getting more and more sensitive and achieving lower detection limits. Thirty years ago, anywhere in the ppm (parts-per-million) range was good enough. But now, it is ppt (part-per-trillion); that means that we have increased by 106 sensitivity.
MT: What does it mean to Metrohm that the EPA uses your Hexachrom IC systems?
JG: It means a lot because any U.S. regulatory organization is viewed as using cutting-edge methods, on a global scale. When EPA published the method with the Metrohm name in it, it meant a lot for Metrohm as a global company. It not only brings credibility around the globe, but it publicizes the application as well.
MT: What additional IC systems or technologies is Metrohm currently working on?
JG: We are working on delving deeper into speciation—for example, speciation of arsenic, selenium and disinfectant byproducts (DBP). When you use chlorine as your disinfectant and you do have an organic carbon, it forms different halogenetic hydrocarbon species. Defining them and separating them allows you to know the quality of the water, which hadn’t been monitored at a low level previously. The goal is the make the detectors as sensitive as possible.
For more information on Metrohm’s line of IC products, please visit www.metrohmusa.com/hexachrome, or call 813-316-4700. For more information on chromium in drinking water, and how it affects your home state, please visit the EPA’s website at water.epa.gov/drink/info/chromium.