Name: maldi-tof for rapid sample analysis
Uploaded: 2025-12-16T13:53:43.000Z
Duration: 1 min 19 s
Channel: JoVE

MALDI-TOF mass spectrometry is an analytical technique for detecting and characterizing biological samples such as peptides, carbohydrates, and DNA.MALDI-TOF contains an ionization source to generate gaseous ions and a mass analyzer for ion detection based on the ion&#8217;s time of flight.First, the sample peptides are mixed with a matrix and loaded onto the target plate.When struck by a laser, the sample desorbs, producing positively charged ions. That is why this technique is called matrix-assisted laser desorption ionization.Ions then move into the mass analyzer, where they are sorted, depending on the time required to travel through the length of the flight tube.This time of flight is proportional to the square root of the mass-to-charge ratio. Among the ions with the same charge, smaller ions move faster.The detector collects these ions and passes the information to a computerized system. It generates a peptide mass fingerprint to identify the unknown protein by comparing the peptide mass with a database library.

maldi-tof mass spectrometry

MALDI-TOF Mass Spectrometry

Mass spectrometry is a powerful characterization technique that can identify and separate a wide variety of compounds ranging from chemical to biological entities, based on their mass-to-charge ratio (m/z). The instruments that allow this detection, known as mass spectrometers, have three components: an ion source, a mass analyzer, and a detector. These spectrometers differ based on the nature of their ion source and analyzers.Matrix-assisted laser desorption ionization (MALDI) is a commonly used ionization source in mass spectrometers. It enables the soft ionization of biological molecules like peptides, lipids, and saccharides without fragmenting them. This means they can be analyzed intact as the sample integrity is maintained.In MALDI, the sample is mixed with a compatible matrix that is organic molecules. When the laser strikes the sample, the matrix functions as a mediator for energy absorption, yielding the intact sample analyte ions. The matrix molecules energetically ablate from the sample surface, absorb the laser energy and carry the sample molecules into the gas phase. The sample molecules are usually ionized during the ablation process to carry a single positive charge.The desorbed sample ions carrying the charge are then directed towards the mass analyzer, usually a time-of-flight (TOF). The ions pass through a field-free drift region, which allows separation based on their mass/charge ratio, allowing the smaller ions to reach the detector first.MALDI-TOF instruments are often connected with a reflectron that reflects ions increasing the ion flight path. This increased flight time between ions of different m/z allows better sample resolution where ions of the same mass reach the detector simultaneously. MALDI sources can be coupled with other analyzers, including triple quadrupoles and Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometers. The MALDI-FT-ICR is known for its high mass resolution, wherein the sample ions carrying the charge move to an ICR cell and cyclotron in a magnetic field while separating on m/z.With a couple of limitations, like, the possibility of photodegradation by the laser for some sample types, absorption of the laser by a few fluorescent analytes that could affect the results, an acidic matrix that could alter sample nature, etc., overall, this technique has vast applications.&#160; It can analyze protein samples isolated by electrophoresis or chromatography, peptides, carbohydrates, DNA, identify microorganisms from clinical samples and ascertain biomolecules in tissues, among many others.

Mass spectrometry is a powerful characterization technique that can identify and separate a wide variety of compounds ranging from chemical to biological ...

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Cell Biology

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Analyzing Cells and Proteins

KEY TERMS AND CONCEPTS

maldi-tof for rapid sample analysis

MALDI-TOF mass spectrometry analyzes compounds by their mass-to-charge ratio, or m/z. It is a powerful way to detect and separate many chemical and biological samples. A mass spectrometer has three main parts: an ion source, a mass analyzer, and a detector. These parts work together, and the design can change depending on the source and analyzer used.

Matrix-assisted laser desorption ionization, or MALDI, is a common ion source in these instruments. It creates soft ionization, which helps biological molecules such as peptides, lipids, and saccharides stay intact instead of breaking apart. The sample is mixed with an organic matrix, which is a compatible helper molecule. When the laser hits the sample, the matrix absorbs the energy and helps release intact sample ions into the gas phase.

During this process, the sample molecules are usually given a single positive charge. The charged ions then move into the mass analyzer, which is often a time-of-flight, or TOF, analyzer. In the field-free drift region, ions separate by m/z, so smaller ions reach the detector first. MALDI-TOF systems often include a reflectron, which reflects the ions and increases their flight path. This longer path improves resolution because ions with the same mass can reach the detector together.

MALDI can also be paired with other analyzers. These include triple quadrupoles and Fourier transform ion cyclotron resonance, or FT-ICR, mass spectrometers. MALDI-FT-ICR offers high mass resolution. In this setup, the charged ions move into an ICR cell and cyclotron in a magnetic field while they separate by m/z.

The technique has some limits. Some samples may photodegrade because of the laser. Fluorescent analytes can also absorb the laser and affect the result. In some cases, an acidic matrix may change the sample. Even with these limits, MALDI has many uses. It can analyze proteins isolated by electrophoresis or chromatography, as well as peptides, carbohydrates, and DNA. It is also used to identify microorganisms from clinical samples and to detect biomolecules in tissues.

MALDI-TOF for Rapid Sample Analysis

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MALDI-TOF mass spectrometry analyzes compounds by their mass-to-charge ratio, or m/z. It is a powerful way to detect and separate many chemical and biological samples. A mass spectrometer has three main parts: an ion source, a mass analyzer, and a detector. These parts work together, and the design can change depending on the source and analyzer used. Matrix-assisted laser desorption ionization, or MALDI, is a common ion source in these instruments. It creates soft ionization, which helps...

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NMR Spectroscopy in Biology and MRI

Nuclear magnetic resonance (NMR) spectroscopy is a useful analytical tool in biology. Researchers have used it for more than 50 years. F. Bloch and E. Purcell developed NMR in 1946 and received the 1952 Nobel Prize in Physics for this work. NMR studies biological macromolecules and small molecules. These include proteins, nucleic acids, lipids, and organic compounds such as pharmaceutical drugs. The technique works by using the magnetic properties of certain nuclei. The basic idea behind NMR...

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key terms and concepts

Learn how MALDI-TOF uses a laser, matrix, and time-of-flight analyzer to identify peptides, proteins, DNA, and microbes by m/z.

MALDI-TOF for Rapid Sample Analysis | JoVE K12

cell biology

JoVE Core Cell Biology illustrates complex cellular processes in easy-to-understand yet comprehensive animated video lessons. This collection focuses on the essential components and functions of cells, including organelles and membranes, cellular transport, and cell energetics. It is complemented by scientist-in-action videos that demonstrate the application of cell biology in real-world research experiments.

MALDI-TOF for Rapid Sample Analysis

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