Researchers at New York University (NYU) recently developed a new method for simultaneous measurement of 71 inorganic elements in liquids — including groundwater. The method, utilizing sequential inductively coupled plasma-mass spectrometry, makes element testing much faster, more efficient, and more comprehensive than was possible in the past.
The NYU 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—developed by researchers at the isotope laboratory of NYU College of Dentistry and described in the journal RSC Advances, published by the Royal Society of Chemistry—may be used to explore and understand the distribution of inorganic elements beyond the few that are typically measured. It has implications for fields such as nutrition, ecology and climate science, and environmental health.
An analytical technique called inductively coupled plasma mass spectrometry (ICP-MS) is used to measure elements. Historically, ICP-MS instruments have measured elements sequentially, or one by one, but a new type of ICP‐MS instrument at NYU College of Dentistry and roughly two dozen other places around the world 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. We’re able to measure the elements in far less time, at far less expense, using far less material,” said Timothy Bromage, professor of biomaterials and of basic science and craniofacial biology at NYU College of Dentistry and the study’s senior author.
This technological advancement may help to fill gaps in our understanding of element distributions and concentrations in substances like water. For instance, the U.S. 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,” said Bromage.
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.
In each sample, Bromage and his team found a distinct “fingerprint” or elemental pattern, suggesting that samples can be recognized and differentiated by these patterns. The elemental content of water, for example, 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.