With the right combination of technological advances, a platform can abolish the need for an ongoing use of argon
The consumables in a laboratory create a range of challenges, from expense and inconvenience to downtime and required maintenance. Scientists can face all of those obstacles when using a platform that combines inductively coupled plasma (ICP) with optical emission spectroscopy (OES). For elemental analysis of a wide range of samples, researchers use ICP-OES. The samples could be soil, water, or materials from industrial processes. As a result, scientists use ICP-OES to monitor compliance with government regulations or analyze samples in environmental cleanups and in industries of all sorts. Despite that wide-ranging utility, this technology can give scientists some unwanted problems, and one of them is coping with gas as a consumable.
In many ICP-OES systems, ICP excites elements in a sample, and diffraction gratings separate the emitted light in spectral lines that a detector analyzes. In most platforms, the diffraction comes from echelle gratings, which are open to the surrounding environment. The oxygen and water in the air remove any signals below 180 nanometers, which can include many of the elements likely to be analyzed. A traditional ICP-OES platform prevents absorption-based transparency loss with an ongoing flow of argon or nitrogen gas.
This can cause several problems. For one thing, this process involves fill-and-purge steps with the gas, and that can introduce contamination to the optical system. When that happens, the device requires maintenance, which adds expense and downtime.
Moreover, making the measurements in an argon or nitrogen environment must be done consistently, because pressure changes in the optical system change the diffraction index, which produces drift in wavelength measurements. So, while purging and filling, the pressure must be carefully controlled to produce accurate results.
Beyond the impact on the results, a fill-and-purge system takes time and consumes gas. For example, purging enough air from an ICP-OES platform’s optical pathway can take two hours. Rather than doing that every time that an instrument needs to be used, many labs keep an instrument on standby purge—constantly removing air—and that can use a liter of gas every minute, even when the instrument is not in use. That loss of gas quickly adds up as a lab expense. Estimates indicate that most traditional ICP-OES systems use 600 cubic meters of gas a year for purging, which is worth about $3,800.
Problems like this drive engineers to build ICP-OES systems that remove the gas-related pathway to contamination and reduce the consumable aspect as much as possible.
A saving seal
SPECTRO uses argon in its ICP-OES platforms. This gas, discovered in 1894 by chemists Sir William Ramsay and Lord Rayleigh, is pretty easy to find as it is the third most abundant gas in the earth’s atmosphere. That aside, it’s worth reducing the amount of argon used in an ICP-OES platform.
To alleviate some of the problems with standard ICP-OES systems, SPECTRO analyzers use a sealed optical system. Rather than the fill-and-purge cycles used by most platforms, SPECTRO’s analyzers use argon which is recirculated through a cartridge that purifies the gas, so that it can be reused. This permanent supply of argon eliminates the lost gas used in purging. Plus, the cartridge is good for two years of operation.
This system also can be turned on and off as needed—that is, there is no reason for standby running, because the gas is permanently sealed in the ICP-OES system. This not only saves gas but energy, too. Despite no need to keep this ICP-OES instrument in a standby mode, it’s ready to run as soon as it’s turned on—producing stable results even for elements that generate signals in the low-ultraviolet range.
That sealed SPECTRO system includes the Optimized Rowland Circle Alignment (ORCA) technology, which replaces echelle gratings. The SPECTRO system’s optical system gets as much light as possible to the CCD detectors. This sealed system also prevents contamination to the optical system and that optimizes the process, so that the optics always work the same. Plus, the ORCA technology and detectors perform in a consistent environment in terms of gas content and pressure.
Given the broad range of industries and scientists that can use ICP-OES to analyze a sample’s elemental composition, an efficient and reliable platform is needed. Plus, research groups need a system that provides lower lifetime costs and less maintenance, all while continuing to generate accurate results. That ICP-OES platform should also be ready to use when needed.
Reaching all of those objectives, however, demands more than a technological tweak or two. Instead, the entire ICP-OES system must work together, even if the main objective is to reduce the use of gas and make a platform that is ready to produce high-end results without any waiting. The SPECTRO analyzer meets all of those demands, without a lab manager needing to worry about getting argon over and over. Moreover, creating a system that saves gas and stays online more, at least in the case of SPECTRO, also provides more consistent results across a wide range.