Name: hyphenated mass spectrometry methods
Uploaded: 2024-04-04T10:51:34.000Z
Duration: 1 min 21 s
Channel: JoVE

복잡한 혼합물을 분석하려면 분리 방법과 질량 분석법을 순서대로 조합해야 하며, 이를 하이픈으로 연결된 방법이라고 합니다.
GC-MS는 가장 일반적인 하이픈 연결 방법으로, 열적으로 안정적인 휘발성 혼합물을 기체 크로마토그래피로 분리하고 컬럼 출력을 이온화 및 분석을 위해 질량분석기로 지속적으로 전송합니다.
마찬가지로 LC-MS는 질량 분석기와 결합된 액체 크로마토그래피입니다.
일반적으로 비휘발성 극성 또는 이온 화합물과의 혼합물은 액체 크로마토그래피로 분리되며, 출력은 질량 분석기로 보내지기 전에 전기 분무 이온화에 의해 이온화됩니다.
그러나 극성이 적은 분자와의 혼합물은 종종 다른 대기압 이온화 방법을 사용합니다.
Tandem 질량 분석법은 두 개의 질량 분석기가 직렬로 연결된 분석을 위한 또 다른 하이브리드 방법입니다.
GC-MS 및 LC-MS와 달리 탠덤 질량 분석법은 밀리초 단위로 분리되며 더 민감하고 선택적입니다.
흥미롭게도, GC 또는 LC를 탠덤 질량 분석법과 결합하여 GC–MS/MS 및 LC–MS/MS를 형성하여 매우 복잡한 혼합물을 분석할 수 있습니다.

질량 분석법: 복합 분석

Mass Spectrometry: Complex Analysis

질량 분석법은 순수한 화합물을 식별하는 데 중요한 기술입니다. 그러나 복잡한 혼합물의 분석에는 몇 가지 제한 사항이 있습니다. 과도한 단편화로 인해 스펙트럼이 너무 복잡해 해독하기 어려운 경우가 많습니다. 질량 분석법은 적절한 분리 방법과 순차적으로 결합되어 복잡한 혼합물의 분석에 유용한 하이픈 연결 방법을 형성할 수 있습니다.

GC-MS는 혼합물의 정확한 분석을 위해 법의학 및 환경 실험실에서 일반적으로 사용되는 강력한 하이픈 연결 방법입니다. 가스 크로마토그래피는 좁은 모세관 컬럼을 사용하여 열적으로 안정한 휘발성 혼합물의 성분을 분리하고 이를 질량 분석계로 전달하여 분석합니다.

LC-MS는 액체 크로마토그래피와 질량 분석기를 결합하여 비휘발성 혼합물을 분석하는 또 다른 하이픈 연결 방법입니다. 액체 크로마토그래피를 질량 분석기와 호환되게 하려면 극성 및 이온 화합물에 적용할 수 있는 전자분무 이온화 또는 덜 극성인 분자에 적용할 수 있는 대기압 화학 이온화와 같은 적절한 압력 유지 이온화 인터페이스 또는 대기압 이온화 기술이 필요합니다. 사용된.

직렬 질량 분석법이라고 하는 또 다른 하이브리드 방법은 여러 질량 분석기를 순서대로 사용합니다. 다른 하이픈 연결 방법과 비교하여 탠덤 분광법은 화학적 노이즈가 적기 때문에 더 빠르고 민감하며 선택성이 높습니다. 탠덤 분광법은 분리 기술과 추가로 결합하여 보다 복잡한 혼합물 분석을 위해 GC-MS/MS 또는 LC-MS/MS를 형성할 수 있습니다.

모세관 전기영동-질량분석법은 DNA, 단백질, 폴리펩티드와 같은 큰 생체분자를 분석하는 데 일반적으로 사용되는 매우 민감한 기술입니다. 이 방법은 전기분무 이온화 인터페이스를 통과한 후 모세관 유출물을 사중극자 질량 분석기에 공급합니다.

복잡한 혼합물을 분석하려면 분리 방법과 질량 분석법을 순서대로 조합해야 하며, 이를 하이픈으로 연결된 방법이라고 합니다.
GC–MS ...

Education

교육

JoVE Core

Analytical Chemistry

분석 화학

Unit 1

제1단원

Principles of Mass Spectrometry

질량 분석법의 원리

KEY TERMS AND CONCEPTS

주요 용어 및 개념

hyphenated mass spectrometry methods

Mass spectrometry can be paired with separation methods to study complex mixtures. This combination is called a hyphenated method. It helps when a pure mass spectrum is too hard to read because a mixture causes too much fragmentation and too many overlapping signals.

GC-MS is one common hyphenated method. GC stands for gas chromatography, which separates volatile, thermally stable compounds in narrow capillary columns before they enter the mass spectrometer. This approach is widely used in forensic and environmental laboratories for precise mixture analysis.

LC-MS is another important option for nonvolatile mixtures. LC stands for liquid chromatography, and it must be linked to the mass spectrometer with pressure-maintaining ionization interfaces or atmospheric-pressure ionization methods. Electrospray ionization works well for polar and ionic compounds, while atmospheric-pressure chemical ionization is used for less polar molecules.

Tandem mass spectroscopy uses multiple mass analyzers in sequence. Compared with other hyphenated methods, it is faster, more sensitive, and more selective because it creates less chemical noise. Tandem methods can also be combined with separation steps to form GC-MS/MS or LC-MS/MS for even more complex samples.

Capillary electrophoresis-mass spectrometry is another sensitive hybrid technique. It is commonly used to analyze large biomolecules such as DNA, proteins, and polypeptides. In this method, capillary effluents pass through an electrospray ionization interface and into quadrupole mass analyzers.

Hyphenated Mass Spectrometry Methods

mass spectrometry: overview

Mass Spectrometry and Molecular Identity

Mass spectrometry helps identify a compound by measuring its molecular mass and molecular formula. It does this by turning the analyte molecule into ions and then comparing ion abundance with mass-to-charge ratio. One common ionization method is electron ionization, or EI. In EI, high-energy electron beams strike analyte molecules in the gas phase. The beam removes an electron and leaves a molecular ion behind. A molecular ion is a radical cation, so it has a positive charge and an unpaired...

mass spectrometry: isotope effect

Isotope Peaks in Mass Spectra

Isotope peaks in mass spectra show how natural isotope mixtures change the signal of a molecule. Most elements occur as a mix of isotopes, which are atoms of the same element with different numbers of neutrons. Because isotopes have different masses, the same fragment can appear at more than one position in a spectrum. The mass of a molecule depends on which isotopes are present in its atoms. The size of each isotope peak also depends on how common those isotopes are in nature. Carbon is a...

mass spectrometry: molecular fragmentation overview

mass-spectrometry-molecular-fragmentation-overview

Mass Spectrometry Fragmentation Patterns

Mass spectrometry fragmentation patterns show how a molecular ion breaks apart after ionization. When a molecule loses an electron inside the mass spectrometer, its structure becomes unstable. The ion then fragments at bonds that often produce the most stable pieces. One common pattern is cleavage of a single bond in the molecular ion. This break forms a radical and a cation. The bond can split in more than one way, but the favored path is the one that gives the more stable carbocation rather...

mass spectrometers

How Mass Spectrometers Sort Ions

A mass spectrometer sorts charged ions by their mass-to-charge ratio and records their relative abundance. It turns vaporized analyte molecules into ions, separates them, and then measures the signal from each type of ion. The process begins in the ionization chamber. The analyte is in the gas phase inside a vacuum, and it is struck by high-energy electrons. The electrons have about 70 eV of energy, which is enough to remove an electron from the analyte and form a molecular ion. After...

mass spectrum

Reading Peaks in a Mass Spectrum

A mass spectrum shows the charged fragments in an analyte as peaks plotted by mass-to-charge ratio, or m/z. The x-axis gives the mass of each charged fragment divided by the number of charges it carries. The y-axis shows the relative abundance of each charged species based on the signal intensity recorded at the detector. The tallest peak is called the base peak. It is assigned an abundance of 100%, and the other peaks are scaled against it. The peak from the molecular ion is called the parent...

mass spectrum: interpretation

Decoding Molecular Ions in Mass Spectra

Mass spectra help scientists identify an unknown compound by finding the molecular ion peak. The molecular ion peak shows the mass of the intact molecule, but it is often weak or missing because high-energy electron beams cause strong fragmentation. When that happens, a soft-energy electron beam can be used to scan the spectrum and improve the molecular ion signal. Other ionization methods can also give a stronger molecular ion peak. Chemical ionization, field ionization, and desorption...

mass analyzers: overview

Mass Analyzers and Ion Separation

Mass analyzers separate ions by their mass-to-charge ratio, or m/z, in a mass spectrometer. After a sample is vaporized in the ionization chamber, it is hit with a high-energy electron beam. This creates a radical cation and also produces neutral molecules, radicals, and cations. Negatively charged accelerator plates then push the cations into the mass analyzer, where they are sent on to the detector. Several mass analyzer designs are commonly used. These include magnetic sector,...

mass analyzers: common types

Quadrupole, TOF, and Ion Trap Analyzers

Quadrupole, time-of-flight, and ion trap mass analyzers each separate ions in a different way. They are common tools in mass spectrometry and help sort ions by their mass-to-charge ratio, or m/z. A quadrupole mass analyzer uses four cylindrical metal rods arranged in a diamond shape. The rods carry a direct current, or DC, voltage and a radio-frequency AC voltage. Ion motion depends on the field strength, so only ions with a certain m/z resonate and reach the detector at that setting. This...

high-resolution mass spectrometry (hrms)

Mass Accuracy in HRMS Analysis

High-resolution mass spectrometry separates ions by very small differences in mass. This matters because atomic masses are not always exact whole numbers, even though they are often rounded for simple calculations. Atomic mass is usually estimated by adding the masses of protons and neutrons. In reality, the proton and neutron do not have exactly the same mass. That creates small differences when atomic masses are compared to the simplest hydrogen atom. Helium, for example, is made of 2...

mass spectrometry: complex analysis

Mass spectrometry can be paired with separation methods to study complex mixtures. This combination is called a hyphenated method. It helps when a pure mass spectrum is too hard to read because a mixture causes too much fragmentation and too many overlapping signals. GC-MS is one common hyphenated method. GC stands for gas chromatography, which separates volatile, thermally stable compounds in narrow capillary columns before they enter the mass spectrometer. This approach is widely used in...

tandem mass spectrometry

MS/MS Scan Modes and Fragment Ions

Tandem mass spectrometry uses two or more mass analyzers in series to improve selectivity and lower chemical noise during analyte detection. A set of analyzers separated by an interaction cell lets the instrument break ions apart and study the fragment ions that form. Fragmentation happens in the interaction cell and can be caused in several ways. Collision-induced dissociation, or CID, uses inert gases such as nitrogen, argon, or helium. Other methods include surface-induced dissociation...

gas chromatography&ndash;mass spectrometry (gc&ndash;ms)

How GC-MS Separates and Identifies Compounds

Gas chromatography-mass spectrometry (GC-MS) separates compounds in a mixture and then identifies them. A gas chromatograph first splits the mixture into its parts. A mass spectrometer then analyzes each part on its own to determine molecular masses and molecular structures. The gas chromatograph uses a long, narrow capillary column. The inner wall of the column has a polysiloxane coating. This coating serves as the stationary phase. It has a high boiling point, low viscosity, and low polarity.

inductively coupled plasma&#8211;mass spectrometry (icp&#8211;ms): overview

inductively-coupled-plasmamass-spectrometry-icpms-overview

ICP-MS Sample Ionization and Detection

ICP-MS uses an inductively coupled plasma torch to turn samples into ions for mass analysis. Solid samples are first dissolved and volatilized before they enter the hot argon plasma. Solution samples are nebulized, which means they are converted into a fine spray, and then passed through the same plasma. Inside the plasma, the analytes break apart. Their atoms become positively charged ions, along with some molecular species. These positive ions are sent to the mass spectrometer, where they...

inductively coupled plasma-mass spectrometry (icp-ms): interferences

inductively-coupled-plasma-mass-spectrometry-icp-ms-interferences

ICP-MS Signal Interference Sources and Fixes

Inductively coupled plasma-mass spectrometry (ICP-MS) is a sensitive method for elemental analysis, but its spectra can be affected by interferences. These interferences can make the mass signal less accurate, even when the instrument is working well. Spectroscopic interferences happen when ions in the plasma have the same mass-to-charge ratio, or m/z, as the analyte ion. This group includes isobaric interferences, polyatomic ion interferences, and refractory oxide ion interferences. Isobaric...

key terms and concepts

Learn how GC-MS, LC-MS, tandem mass spectroscopy, and capillary electrophoresis-mass spectrometry help analyze complex mixtures in forensic, environmental, and biomolecule studies.

Hyphenated Mass Spectrometry Methods | JoVE K12

analytical chemistry

JoVE Core Analytical Chemistry simplifies complex chemical principles by breaking them down into clear, engaging animations, making topics from SI Units to NMR spectroscopy more accessible and straightforward. Additionally, the scientist-in-action videos highlight the application of these concepts in real-world research conducted in laboratories globally.

Hyphenated Mass Spectrometry Methods

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