A new method for simultaneous measurement of 71 inorganic elements in liquids makes testing faster, more efficient, and more comprehensive than was possible in the past, according to new research.
Researchers studied samples of liquid from a variety of sources worldwide, including tap water from a New York City suburb, snow from Italy and Croatia, rain from Brazil and Pakistan, lake water from Switzerland and Croatia, and seawater from Japan and Brazil.
Testing each sample results in a distinct elemental pattern, creating a “fingerprint” that can help differentiate between substances or trace a liquid back to its environmental origin.
The method can help scientists explore and understand the distribution of inorganic elements beyond the few typical measurements and has implications for fields such as nutrition, ecology and climate science, and environmental health.
Faster and cheaper
Scientists use an analytical technique called inductively coupled plasma mass spectrometry (ICP-MS) to measure elements. Historically, ICP-MS instruments have measured elements sequentially, or one by one, but the new type of ICP‐MS instrument has the potential to measure the complete range of inorganic elements all at once.
“Because of this new method, our mass spectrometer can simultaneously measure all inorganic elements from lithium to uranium,” says Timothy Bromage, professor of biomaterials and of basic science and craniofacial biology at New York University College of Dentistry and senior author of the paper, which appears in RSC Advances.
“We’re able to measure the elements in far less time, at far less expense, using far less material,” Bromage says.
The technological advancement may help to fill gaps in our understanding of element distributions and concentrations in substances like water. For instance, the US Environmental Protection Agency monitors and sets maximum concentration limits for 19 elements in drinking water considered to be health risks, yet many elements known to have health consequences—such as lithium or tin—are neither monitored nor regulated.
“The elemental mapping of concentration levels in bottled and tap water could help to increase our understanding of ‘normal’ concentration levels of most elements in water,” Bromage says.
Tap water and snow
Bromage and his colleagues designed a method for using simultaneous ICP-MS to detect 71 elements of the inorganic spectrum involving a specific set of calibration and internal standards. The method, for which they have a patent pending, routinely detects elements in seconds to several minutes and in samples as small as 1 to 4 milliliters.
The researchers tested the method on water, beverages, and biological samples. Snow contained the most elements of any water sample: 50 in snow they collected in Italy and 42 in a sample from Croatia.
“Such evaluations of snow may represent a new and comprehensive means of surveying atmospheric concentrations of elements and for monitoring element patterns in global airflows,” Bromage says.
When testing tap water, the researchers measured 37 elements when the tap was first turned on, but only 34 elements after the water was running for five minutes, suggesting that elements such as iron and zinc may be leaching from household pipes into the water.
Gold in milk
The researchers also measured elements in bottled water, beer, wine, and milk, as well as in samples of saliva, urine, and blood. Milk was distinguished from the other beverages by its high concentrations of titanium, zinc, palladium, and gold.
In each sample, they found a distinct “fingerprint” or elemental pattern, suggesting that their method can recognize and differentiate samples by these patterns.
For example, the elemental content of water typically reflects its natural environment, so understanding the elemental composition can tell us if water had its origins from a source with volcanic rock versus limestone, an alkaline rock. In bottled water, the researchers observed variations that are likely a result of one being bottled at the source and one being chlorinated for transportation from the source to the bottling plant.
“Water is an arbiter of how a system actually works.”
Future studies will measure and report on larger samples of water, wine, milk, and other fluids; a study of more than 1,000 wines from 34 countries is in progress. In addition, once researchers have established elemental patterns for specific environments, the method can help answer questions in fields that relate the present to the past, such as the paleoenvironment and climate change.
“Water is an arbiter of how a system actually works. If you sample the water from a pond or river and measure the elements, you are measuring the stuff that becomes incorporated into all life—water feeds the plants, animals eat the plants, we eat the plants and animals,” Bromage says.
“We could use this knowledge to study human fossils and potentially retrodict what the nature of the region’s water was hundreds of thousands or millions of years ago,” he says.
The Max Planck Prize, which the German Federal Ministry of Education and Research endowed to the Max Planck Society and the Alexander von Humboldt Foundation, as well as Human Microassay Inc. funded the work.
Source: NYU
