Name: ms/ms scan modes and fragment ions
Uploaded: 2025-12-12T12:28:58.000Z
Duration: 1 min 21 s
Channel: JoVE

Tandem mass spectrometry, or MS/MS, combines two mass analyzers in sequence, connected by a collision or interaction cell.
First, the samples are ionized to generate a mixture of ions, which enters the first mass analyzer.
This analyzer separates the ions and selects only a particular ion&#8212;the precursor ion&#8212;to move into the collision cell.
The collision cell contains inert gas molecules, which collide with precursor ions, fragmenting them into product ions.
These ions are run through the second mass analyzer, where they are separated and finally detected.
MS/MS generates various spectra.
Product-ion spectra are obtained when the first analyzer selects a precursor ion and the second analyzer scans all the masses.
Precursor-ion spectra are generated by scanning through precursor ions in the first analyzer and selecting a product-ion in the second analyzer.
To obtain neutral loss spectra, both mass analyzers are scanned together, with the second analyzer offset by the mass of a selected neutral fragment.
MS/MS is used for structural elucidation and complex mixture analysis.

espectrometria de massa em tandem

Tandem Mass Spectrometry

A espectrometria de massa em tandem &#233; uma t&#233;cnica que utiliza m&#250;ltiplos analisadores de massa em s&#233;rie para obter maior seletividade e reduzir o ru&#237;do qu&#237;mico durante a detec&#231;&#227;o do analito. Instrumentos com m&#250;ltiplos analisadores separados por uma c&#233;lula de intera&#231;&#227;o permitem a fragmenta&#231;&#227;o secund&#225;ria e o estudo selecionado dos &#237;ons do fragmento.
Fragmenta&#231;&#245;es secund&#225;rias ocorrem na c&#233;lula de intera&#231;&#227;o e podem ser induzidas por v&#225;rios fatores. A fragmenta&#231;&#227;o induzida pela colis&#227;o com gases inertes, como N_2, Ar, He, etc., &#233; chamada de dissocia&#231;&#227;o induzida por colis&#227;o (CID). Outras t&#233;cnicas envolvem a intera&#231;&#227;o com a superf&#237;cie atrav&#233;s da dissocia&#231;&#227;o induzida pela superf&#237;cie (SID); intera&#231;&#227;o com el&#233;trons de baixa energia, chamada de dissocia&#231;&#227;o por captura de el&#233;trons (ECD); ou atrav&#233;s de um feixe de laser intenso, denominado dissocia&#231;&#227;o fotoinduzida (PID).
A espectrometria de massa em tandem pode ser usada para v&#225;rios experimentos, variando o modo de opera&#231;&#227;o dos dois analisadores de massa. Quando o primeiro analisador de massa seleciona um &#237;on precursor espec&#237;fico e o segundo analisador de massa varre todos os &#237;ons do produto fragmentados, isso &#233; chamado de varredura de &#237;ons de produto, e os espectros obtidos por este experimento s&#227;o chamados de espectros de &#237;ons de produto. Alternativamente, quando o primeiro analisador de massa varre todos os &#237;ons precursores e o segundo analisador de massa seleciona um &#237;on produzido espec&#237;fico, isso &#233; chamado de 'modo de &#237;on precursor', e os espectros s&#227;o denominados espectros de &#237;ons precursores. Outra experi&#234;ncia pode ser realizada varrendo ambos os analisadores simultaneamente com um deslocamento de massa igual a um fragmento neutro perdido pelo &#237;on a ser monitorado. Tal modo &#233; chamado de 'modo de varredura de perda neutra', e os espectros correspondentes s&#227;o chamados de espectros de perda neutra.
A instrumenta&#231;&#227;o da espectrometria de massa em tandem pode ser variada. Os espectr&#244;metros tandem no espa&#231;o usam dois analisadores de massa independentes em duas regi&#245;es diferentes no espa&#231;o, por exemplo, um espectr&#244;metro de massa de quadrupolo triplo e um espectr&#244;metro TOF-TOF. Por outro lado, um espectr&#244;metro tandem-in-time, como um instrumento quadrupolo de armadilha de &#237;ons (ion-trap), usa a mesma regi&#227;o espacial para fragmentar os &#237;ons e dissociar e analisar um &#237;on selecionado de interesse, mas em momentos diferentes, expelindo os &#237;ons indesejados. Espectr&#244;metros tandem-in-time podem ser usados &#8203;&#8203;para realizar experimentos MS^n.

Espectrometria de Massa em Tandem

Tandem mass spectrometry, or MS/MS, combines two mass analyzers in sequence, connected by a collision or interaction cell.
First, the samples are ionized ...

Education

JoVE Core

Analytical Chemistry

Química Analítica

Unit 1

Unidade 1

Principles of Mass Spectrometry

Princípios da Espectrometria de Massas

KEY TERMS AND CONCEPTS

TERMOS E CONCEITOS-CHAVE

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 (SID), electron-capture dissociation (ECD), and photo-induced dissociation (PID), which uses an intense laser beam.

Tandem mass spectrometry can also run in different scan modes. In a product-ion scan, the first mass analyzer selects one precursor ion, and the second analyzer scans the fragment product ions. The result is a product-ion spectrum. In precursor-ion mode, the first analyzer scans precursor ions, and the second selects one product ion. This gives a precursor-ion spectrum. A neutral-loss scan is different again. Both analyzers scan together with a mass offset that matches the neutral fragment lost by the ion being monitored.

The instrument design can also vary. Tandem-in-space spectrometers use two separate mass analyzers in different regions, such as a triple quadrupole mass spectrometer or a TOF-TOF spectrometer. Tandem-in-time spectrometers, such as a quadrupole ion trap, use the same space at different times to fragment and analyze a chosen ion by removing unwanted ions. These instruments can also perform MSn experiments.

MS/MS Scan Modes and Fragment Ions

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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...

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key terms and concepts

Learn how tandem mass spectrometry uses CID, SID, ECD, PID, and scan modes like product-ion, precursor-ion, and neutral-loss scans to analyze fragment ions.

MS/MS Scan Modes and Fragment Ions | JoVE K12

analytical chemistry

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MS/MS Scan Modes and Fragment Ions

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