By definition a trace metal exists in a sample or compound at an extremely low, often difficult to detect, concentration. However, though the concentration of metal present may be low, depending on the metal and the sample where it is found, it could lead to very serious problems ranging from purity or quality issues in a substance, up to posing a health and safety risk for those exposed to the metal. This makes detecting and accurately quantifying the trace metal extremely important. An effective industrial lab method for doing precisely that is Inductively- Coupled Plasma-Mass Spectrometry (ICP-MS). Let’s take a look at how ICP-MS works and its role in reliably detecting trace metals.

What Is Inductively-Coupled Plasma-Mass Spectrometry?

ICP-MS is sophisticated laboratory analysis method that takes one of the most well known types of lab analysis, mass spectrometry, and combines it with inductively coupled plasma in order to separate out and then quantify the concentration levels of different ions within a sample. The inductively coupled plasma energizes the molecules within the sample, ionizing them so that they can then be detected with mass spectrometry. Let’s take a closer look at each of these processes to better understand how they work in conjunction with each other.

What Is Inductively-Coupled Plasma?

Inductively coupled plasma (ICP) is a plasma that has been ionized using an electromagnetic coil to inductively heat a gas. The heating process makes the gas electrically conductive, which in turn causes the atoms in the sample that is being analyzed to convert to ions so that they can then subsequently be separated and detected with mass spectrometry. The inductively coupled plasma phase of the process occurs within concentric tubes or channels of the ICP torch.

The gas used for this process is argon and it is heated to extremely high temperatures, often as much as 6,000°K-10,000°K. Then the sample is introduced into the ICP torch by nebulizing it. Because the argon gas is so hot it is an excellent ion source and as the molecules in the sample collide with the molecules of argon they exchange electrons and become ionized.

How Does Mass Spectrometry Work?

Mass spectrometry (MS) is an analytical technique that is designed to determine the type of molecules present as well as their concentration levels. The mass spectrometer contains a mass analyzer that is used to identify the type of molecules present. Then a detector is used to determine the abundance of these molecules, thereby providing accurate and detailed information about the presence and concentration of molecules like trace metals in a sample.

Different mass spectrometers use different types of ionizers, but for ICP-MS the ions come from the inductively coupled plasma discussed above. The ions are extracted from the plasma and into the mass spectrometer using interface cones.

Why Is Detecting Trace Metals Important?

ICP-MS is an extremely sensitive and accurate process. It is capable of detecting extremely low concentrations of metals, in the order of parts-per-billion, and for some non-metals it can even detect concentrations as low as parts-per-quadrillion. This extreme precision is important because many industries must closely monitor the amount of trace metals present.

In some chemical and petrochemical industries OSHA mandates testing for trace metals such as mercury, lead, and arsenic in working environments as a way to protect workers from serious toxicity and health concerns. Detecting the presence of trace metals in consumer products is also crucial for keeping the public and the environment safe.

CPI offers Inductively-Coupled Plasma-Mass Spectrometry (ICP-MS) as one of our core lab services. We also understand that companies who need these tests also need the results quickly. That is why in most cases we are able to deliver highly detailed reports within a few hours of completing testing, or if it is not during business hours then by 10:00am the following day. Accurately detecting trace metals is important and with ICP-MS and other advanced methodologies CPI is proud to serve the Golden Triangle and Houston area industrial sectors with dependable lab services.