Teledyne Leeman Labs Blog

Since the 1970s, petrochemical labs have used Inductively Coupled Plasma - Optical Emission Spectroscopy (ICP-OES) as a key technique to determine a range of elements and concentrations in both aqueous and organic samples. ICP is compatible with a variety of organic solvents, which means it permits the preparation of a broad range of sample types using a simple dilution.

Steel is critical to our modern world, with companies producing more than 1.6 billion tons every year[i]. When it comes to high-carbon steel, the higher the carbon content, the harder and stronger the steel is.  As carbon is reduced, the iron becomes more flexible and easier to form. Carbon steel makes up more than 85% of the steel produced in the United States, and while other alloys can be used to change steel properties, such as Manganese and Vanadium, carbon is the most cost-effective alloying material for iron.

The instruments being marketed today have reached a level of sophistication that would not have seemed possible 40 years ago. Though the fundamental principles of the technique have not changed, the technology has seen significant advancements, especially in the design of the ICP source, optical spectrometer and detection systems. Simultaneously, milestones in real-time elemental coverage, sample throughput and ease-of-use, continue to make it easier to reach new pinnacles in productivity and data quality.

With the 1970s known as the birth of ICP-OES and the 1980s as the era of versatility, the decade of the 1990s was the dawn of some major breakthroughs in ICP optical spectrometry.  These breakthroughs centered on the Plasma orientation and solid state Detectors, which initiated hopes of simultaneous detection of the entire ICP spectrum. 

In part I of the Evolution of ICP, we focused on the first decade of ICP instruments, which were based on the Paschen-Rünge optical design. In part II of the blog series, we jump into the 1980s, and the next era in innovation.

The wavelength restrictions associated with the Paschen-Rünge optical design led to the development of sequential spectrometers in the early 1980s.  Most of these instruments relied on the principle of scanning a dispersive optic (typically a ruled or holographic diffraction grating) to select the specific wavelength of light corresponding to the element of interest. These instruments were extremely versatile, possessing the ability to access nearly any wavelength in the electromagnetic spectrum from 160 - 900 nm.  Their downside lay in their ability to access only one wavelength at a time (thus named sequential), resulting in slow analysis times. On an instrument of this type, a typical analysis could take several minutes to cover the 10 to 20 elements of interest. A schematic diagram of a typical scanning sequential spectrometer is shown in the schematic below:

Since its commercial inception in 1974, ICP-OES has seen significant technological advancements over its 39-year lifespan.  In this four-part blog series, we will summarize the evolution of ICP-OES technology and show how it has come to be applied to an ever-growing amount of sample types and elements of interest, as it has matured.  Each blog post will cover the significant milestones that have occurred in ICP-OES through the past four decades.  Because the ICP-OES specialization is very much a language of its own, useful terminology will appear in bold and will be defined in an upcoming downloadable glossary of ICP-OES Terms and Definitions.

Less than 40 years ago in 1978, the Communist dictator of Romania ordered the 400 families living in the small village of Geamana to leave their homes so that the country could build a copper mine. Unfortunately, the people did not have much choice as the village was to become an artificial lake for the toxic waste from the Rosia Poieni, one of Europe’s largest copper mines. The water that covers Geamana is laced with cyanide and other chemicals, making the area uninhabitable. Recently, the website Roadtrippers published several pictures from the abandoned village.

Unfortunately, the fate of Geamana is not uncommon. In the United States, the area around Treece, Kansas and Picher, Oklahoma was ranked in 1981 by the Environmental Protection Agency as the most contaminated in the country. The contamination was the result of extensive lead and zinc mining. In the 1920s, the area was the number one producer of the elements in the United States, supplying the metals for ammunition during the World Wars. While the metals were extracted, the waste was piled up around the town into mounds of contaminated gravel that still litter the landscape. A New York Times article from May 2012, describe the conditions:

More than 144 homes in a two-square mile southeast of Los Angeles County are the focus of lead contamination test after the California Department of Toxic Substances Control detected high levels of lead in soil near a temporarily closed battery recycling plant. In the fall of 2013, elevated levels of lead at 39 homes and a preschool near the plant were blamed on air pollution from the plant and prompted local officials to issue health warnings and push for additional testing. State regulators expanded the lead soil testing to include more than 144 homes in Vernon, California.