Are you interested in discovering the basics of ICP-MS? ICP MS instruments are used to analyze liquids and can detect elements found in the periodic table. However, trying to learn the fundamentals of ICP-MS can be a daunting task. Don’t worry; this beginner’s guide can provide what you need to know. You better get started!
What is ICP-MS?
The ICP-MS (Inductively Coupled Plasma Mass Spectrometry) is an analytical instrument that measures the composition of an element in a sample. This instrument is considered one of the most accurate and precise analytical methods available today. You must use the best quality standards to get the best results from your ICP-MS analysis.
The ICP torch vaporizes the sample, which is then introduced into the plasma chamber. The plasma converts the sample into ions by adding or subtracting electrons from the molecules until they reach a stable state. The ions are then accelerated through an electric field toward the detector, where their mass-to-charge ratio is measured.
This method is frequently used for trace analysis because it has excellent sensitivity and precision. ICP-MS only works well with non-volatile samples that can be vaporized easily, such as metals, inorganic compounds, and some organic compounds. This tool can determine the chemical compositions of elements present in samples at very low concentrations for environmental and chemical analysis.
How does it work?
When you first set up your ICP-MS instrument, you may need to calibrate it by running a series of standard solutions through the system. These solutions are typically made up of known concentrations of elements or compounds. Solutions can be purchased from companies that manufacture glassware and supplies for lab equipment.
The process begins when you add your sample to a vial, which is then heated in an oven at a high temperature. The sample is vaporized and injected with radio frequency energy into the surrounding plasma torch. This causes atoms from the sample to ionize (gain or lose electrons), creating positively charged ions and negatively charged ions.
The positively charged ions are attracted to an electrode, which pulls them through a magnetized tube toward another electrode. This tube collects all the positively charged ions. It holds them until they eventually fall onto an atomizer plate below, where they’re sprayed into a mass spectrometer chamber where their masses identify them.
What Kinds of things can an ICP-MS measure?
ICP-MS is an analytical technique that measures a sample’s atoms, ions, and molecules’ mass. It’s used in many industries, including petroleum refining, chemical manufacturing, environmental monitoring, and medical diagnostics. The tool can also measure various elements, including hydrogen, carbon, nitrogen, oxygen, and sulfur.
ICP-MS is an extremely sensitive analytical technique, which significantly increases the range and types of samples that can be analyzed compared to other methods. In addition, ICP-MS has a high degree of specificity due to its ability to measure isotopes. When you have a sample that may contain multiple elements, ICP-MS is often the best way to measure their concentrations.
The main applications of ICP-MS include:
• Assessing heavy metal contamination in water sources.
• Detecting illegal drugs in blood samples.
• Measuring the concentration of vitamins and minerals in food supplements.
• Conducting Elemental analysis.
What makes up the ICP-MS components?
Everything that goes into an ICP-MS instrument is designed to support the plasma and the mass spectrometer. The mass spectrometer is the instrument’s heart; it’s where we get our data. It’s also where we do a lot of our calibration. We must have good sensitivity and calibration to get accurate results from our analyzers. It comprises the following components:
Making the Droplets
The majority of samples that are put into an ICP-MS system are liquids. Before being injected into the argon plasma, the liquid sample must be broken up into tiny droplets. Using a Peristaltic pump, the liquid sample can be added to a nebulizer to produce an aerosol of tiny droplets. You may use nebulizers, either thermal or dynamic.
Nebulizers have many advantages over other methods of introducing an aerosol into an analytical instrument like ICP-MS or AAS. They produce very small particles that may not clog the detector. The process must not cause interference with other elements in your sample solution. They also allow you to analyze samples that would otherwise be too thick for analysis.
Creating Ions
The plasma produced by the ICP torch produces a high-temperature region with multiple applications. It serves as an ionization source for the gas introduced into the plasma torch. It can cut or weld metals and other materials to heat the gas. Finally, the plasma conveys heat from one part of a workpiece to another.
The ionization process begins when an electrical current passes through a plasma torch filled with argon gas. This causes some argon atoms to be stripped of electrons and become ions. The stripped atoms collide with other argon atoms, stripping them in turn. Millions of free electrons may move very quickly and collide with each other over and over again.
Sampling Ions
The Two-cone designs are a common way to sample ions in an ICP-MS system. This design is a modification of the quadrupole rod set, where two rods are placed on either side of the ion source. These cones can increase the mass range of ions that the instrument can resolve. The design has several advantages over the quadrupole rod set.
This allows for better resolution of ions by decreasing the amount of overlap between peaks. The quadrupole rod set produces a single peak for each ion species. With the said design, more than one peak may be observed for each ion species. This is since only one apex of each rod is used in this type of mass spectrometer compared to all four in the quadrupole design.
Providing Operating Pressure
The ICP-MS requires a very high vacuum to operate correctly. This is because the plasma uses large power, and the ions and neutrals must be removed from the chamber so that they do not interfere with the detector’s measured signals. The vacuum is also required to prevent contamination of samples and reagents by air dust or other particulate matter.
The common way to achieve this is by using a turbomolecular pump. Its vacuum system consists of several components, including:
• Vacuum pumps (increases pressure)
• Vacuum regulators (controls pressure)
• Vacuum breakers (stop the flow when it reaches a certain value)
Isolating Photons and Neutral Atoms
The ability to recover the analyte ions from the neutrals and photons is necessary to achieve high performance using ICP-MS. This is because many of the ions produced may be neutral atoms or molecules when using an electron multiplier as a detector. Since these neutral atoms or molecules have no charge, they do not generate any signal and cannot be detected by the detector.
The other problem with neutrals is that they can also generate signals from collisions with electrons in the plasma. These signals can be reduced by increasing the pressure, but this also increases background noise levels. Ions that are not recovered by the ionization process may generally result in poor signal-to-noise ratios.
Operating in the Reaction Cell Mode
Ions produced from the plasma, the sample, or a mix of the two can cause interferences in ICP-MS. It happens when their mass-to-charge ratios are the same as those of the analyte ions. The most common source of interference is using materials containing oxygen or nitrogen. These can often be removed by increasing the flow rate through the torch or by increasing its temperature.
The most common interference in ICP-MS is matrix effects. It occurs when a sample contains elements with a mass-to-charge ratio close to the analytes. Matrix effects result in increased signal intensity for all ions in the spectrum. This can be corrected by applying a correction factor to each ion’s peak intensity. It must be divided by the sample matrix’s total peak intensity of all interferents.
Separating Ions
ICP-MS uses the mass spectrometer as a mass filter to separate. Chemical compounds are divided by mass-to-charge ratio using a mass spectrometer. It accomplishes this by vaporizing the material and then ionizing it with an electron beam. Before being detected, the ions are then accelerated and deflected by electric or magnetic fields.
The mass spectrometer separates the first positive ions from each other by mass, serving as an element filter using ICP-MS. A quadrupole or magnetic sector instrument can select the m/z of interest. The ICP-MS instruments can also use collision-induced dissociation (CID) to break apart specific molecules before detection.
Counting Ions
When employing ICP-MS, the ions released from the mass spectrometer collide with the detector’s active surface. It can produce a detectable electronic signal. This is because a mass spectrometer is simply a device used to measure the mass-to-charge ratio of ions. The ion source used in an ICP-MS is usually an electrothermal vaporization system.
The hot metal filament then causes evaporation of the sample being analyzed. It can produce ionized fragments from the evaporated sample. An electric field then accelerates these fragments toward the entrance slit of a mass analyzer. There may be a collision with a counter electrode and produce either positive or negative ions.
Data Handling and System Controller
ICP-MS instruments are complicated, expensive pieces of equipment. The mass spectrometer is an intricate piece of machinery, and a computer must control it. All ICP-MS instruments require computers and software to control the mass spectrometer and perform calculations on the collected data. The computer system must also interface with other equipment to transfer data into information.
In addition to these tasks, the computer system must provide a user-friendly interface for controlling instrument settings and displaying results. The type of computer used depends on how many samples are processed at once. It also includes the required data analysis and other factors specific to your laboratory’s needs.
In Today’s Biotechnology
The importance of using ICP-MS in a laboratory is manifold. It is a technique that helps analyze the sample’s metals, minerals, and other elements. This device has one of the most prevailing methods for analyzing different types of samples due to its accuracy, reliability, and precision. The main purpose of using ICP-MS in a laboratory is to determine the concentration of various elements present in a sample.
This article is meant to provide a brief introduction to ICP-MS. Why not keep reading if you enjoyed learning about ICP-MS? Discover more about the principles of mass spectrometry and ICP-MS analysis. With that being said, there has been an increasing interest in ICP-MS instruments in recent years, and there is definitely something to it.
