June 28, 2004

UCSC dedicates new W. M. Keck Isotope Laboratory with a symposium on isotope analysis

By Tim Stephens

UCSC dedicated the W. M. Keck Isotope Laboratory in June with a symposium on isotope analysis. The naming of the facility recognizes a $1 million grant from the W. M. Keck Foundation that enabled the campus to buy a state-of-the-art mass spectrometer for isotope analysis of trace elements.

With the addition of this powerful new ThermoFinnigan Neptune mass spectrometer to the existing array of sophisticated spectrometry instruments at UCSC, the campus's analytical facilities are unrivaled on the West Coast.
"Thanks to the generosity of the W. M. Keck Foundation, UC Santa Cruz's research capabilities have achieved a new level, making the campus a center of excellence in the region for trace metal analysis," said Acting Chancellor Martin M. Chemers at the dedication ceremony and symposium held on June 18.

Trace metals include toxic elements such as lead and mercury, as well as biologically essential elements, such as copper and manganese, that can be toxic at high concentrations. UCSC scientists in many different fields, from environmental toxicology to oceanography, are interested in precise measurements of trace elements. In particular, the ability to measure accurately the relative abundances of different stable isotopes of the same element in a sample is important to many researchers.

The Neptune, a multi-collector inductively-coupled plasma mass spectrometer (ICP-MS) from Thermo Electron Corporation, is a new type of mass spectrometer that adds significantly to the scope of science that can be carried out at UCSC. This instrument augments the existing single-collector high-resolution ICP-MS that has played a key role in trace metals research at UCSC since 1995. At that time, the campus was the first institution in the United States to acquire a high-resolution ICP-MS.

In addition to the ICP-MS instruments, the Keck Isotope Lab also houses a thermal ionization mass spectrometer, which has been used to measure calcium, lead, neodymium, and strontium isotopes. The Neptune effectively makes all the elements in the periodic table accessible for the same type of analysis, said Jugdeep Aggarwal, director of the Keck Isotope Laboratory.

"The Neptune has opened up the periodic table for exploration by scientists in a wide range of fields. They can now use isotope analysis to study virtually any aspect of the natural world. It's not a small improvement--it is a major, major advance in capability," Aggarwal said.

Thomas Bullen, a research hydrologist with the U.S. Geological Survey in Menlo Park, gave the first talk of the symposium, offering an overview of topics that are ripe for investigation using the unprecedented capabilities of the Neptune. He was followed by Kenneth Sims of Woods Hole Oceanographic Institution, who described his use of isotope analysis to investigate volcanic processes; Holger Hintelmann of Trent University in Canada, who discussed his work on mercury isotopes in the environment; and Norman Pearson of Macquarie University in Australia, who described special laser techniques for analyzing solid samples.

Aggarwal is currently testing a laser device for use with the Neptune in analyzing solid samples. Researchers can use the laser to vaporize a tiny portion of a solid sample for isotope analysis, giving them the capacity to perform separate analyses on specific parts of the sample. Otoliths, for example, are tiny ear bones in fish that are built up in annual layers like the growth rings of a tree. Isotopic analysis of the layers in fish otoliths using this laser technique can yield clues about the different environments a fish lived in throughout its life.

"The laser system will give us spatial resolution, allowing in situ isotopic analysis of solids, instead of dissolving and purifying the sample first," Aggarwal said.

The Keck Isotope Laboratory is one of the core analytical facilities at UCSC, open to researchers in a variety of disciplines on campus and throughout the UC system. The instruments available in the Keck Isotope Lab and the Marine Analytical Laboratory include, in addition to the Neptune, a thermal ionization mass spectrometer, a high-resolution ICP-MS, and an ICP optical-emission spectrometer.

"It is incredible how much the field of stable isotopes has expanded and how fast it is growing. These really are exciting times in isotope chemistry," said Margaret Delaney, interim campus provost and executive vice chancellor. Delaney, a professor of ocean sciences, hosted the symposium, which was followed by a reception, poster presentations of ongoing research at UCSC, and tours of the new laboratory.

Russell Flegal, professor and chair of environmental toxicology, spearheaded the campus's effort to acquire the Neptune mass spectrometer. He was unable to attend the symposium, but Delaney made a point of acknowledging Flegal's role.

"He helped bring us to this point by leading us all to recognize the need for this instrument and convincing us to pursue it through the Keck Foundation," she said.

The symposium was sponsored by the W. M. Keck Foundation, the Thermo Electron Corporation, and UCSC.

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