Name: quadrupole, tof, and ion trap analyzers
Uploaded: 2024-04-04T10:51:34.000Z
Duration: 1 min 19 s
Channel: JoVE

Dört kutuplu kütle analizörü, üzerine bir DC voltajı ve bir radyo frekansı AC voltajı uygulanan dört paralel çubuktan oluşur.
Burada, alan kuvveti yalnızca belirli m/z değerlerine sahip iyonların alanla rezonansa girmesine ve dedektöre çarpmasına neden olur. Bu analizörler düşük bir çözünürlük sunar.
Diğer bir yaygın analizör, iyon uçuş süresinin kaynaktan doğrusal alansız tüp aracılığıyla dedektöre ölçüldüğü uçuş süresi analizörüdür.
Tüm iyonlar yaklaşık olarak aynı kinetik enerjiye sahiptir, bu nedenle daha hafif iyonlar daha yüksek hızlara sahiptir ve bu da daha kısa uçuş sürelerine neden olur.
Çözünürlüğü iyileştirmek için reflektörler veya iyon reflektörleri kullanılır. Aynı kütleye sahip iyonlar arasındaki kinetik enerji farklarını düzelterek daha enerjik iyonları yavaşlatırlar.
Diğer bir alternatif, bir halka elektrot ve bir çift uç kapak elektrotundan oluşan üç boyutlu dört kutuplu iyon tuzağıdır. Bir radyo frekansı voltajı, halkada salınan iyonları yakalar.
Radyo frekansı voltajını artırarak, giderek daha ağır iyonlar stabilize olur ve seçici olarak dedektöre fırlatılır.

kütle analizörü: yaygın türler

Mass Analyzers: Common Types

Dört kutuplu kütle analizörü, bir DC voltajı ve bir radyo frekansı AC voltajı taşıyan bir elmas içinde düzenlenmiş dört silindirik metal çubuktan oluşur. İyonların dört kutuplu boyunca hareketi alan gücüne bağlıdır ve yalnızca belirli bir m/z'ye sahip iyonların başarılı bir şekilde rezonansa girmesine ve belirli bir alan gücünde dedektöre çarpmasına neden olur. Bu analizörlerin iletim hızı yüksek olmasına rağmen, düşük çözünürlük nedeniyle numunenin tam element bileşimi belirlenememektedir; ancak uygun maliyetlidirler. Dört kutuplu bir analizörün tipik çözünürlüğü 1 Da'dır (veya 1 u).

Uçuş süresi (TOF) analizöründe, bir iyonun kaynaktan doğrusal alansız sürüklenme tüpünden dedektöre kadar uçuş süresi mikrosaniye cinsinden ölçülür ve bu süre bir m/z değerine dönüştürülür. İyonlar sürüklenme tüpüne yaklaşık olarak aynı miktarda kinetik enerjiyle girerler. Buna göre farklı m/z değerlerine sahip iyonlar farklı hızlarla hareket ederek dedektöre farklı zamanlarda ulaşır. Daha hafif iyonlar daha yüksek hızda hareket eder, bu da daha kısa uçuş süresine ve nispeten zayıf çözünürlüğe neden olur. Çözünürlük, iyonlara verilen kinetik enerji miktarındaki farklılıklar nedeniyle de bozulabilir, bu da aynı m/z'ye sahip iyonların farklı hızlara sahip olmasına neden olur. Bu nedenle dedektöre olan mesafeyi artırmak ve iyonları yavaşlatmak için bir reflektron (veya iyon aynası) kullanılır. Daha enerjik iyonlar daha büyük bir yavaşlama yaşar, böylece reflektron kinetik enerji yayılımını düzeltir ve genel olarak daha iyi bir çözünürlük sağlar. Ayrıca TOF analizörleri yüksek hassasiyet sunar.

Üç boyutlu dört kutuplu iyon tuzağı analizörleri bir halka elektrot ve iki uç kapak elektrodundan oluşur. Bir radyo frekansı voltajı halkada salınan iyonları yakalar. Radyo frekansı voltajının arttırılması, daha ağır iyonları stabilize eder ve bunları, uç kapaklardaki açıklıklar yoluyla seçici olarak dedektöre fırlatır. Diğer kütle analizörleri iyonların yalnızca küçük bir kısmının dedektöre ulaşmasına izin verirken, üç boyutlu dört kutuplu iyon tuzağı iyonların yarısının dedektöre ulaşmasını sağlayarak bu analizörleri daha hassas hale getirir. Ancak iyon tuzağında depolanan çok sayıda iyon nedeniyle uzay yükü etkileri çözünürlüğün azalmasına neden olur.

Kütle Analizörü: Yaygın Türler

Dört kutuplu kütle analizörü, üzerine bir DC voltajı ve bir radyo frekansı AC voltajı uygulanan dört paralel çubuktan oluşur.
İşte, tarla ...

Education

JoVE Core

Analytical Chemistry

Analitik Kimya

Unit 1

Ünite 1

Principles of Mass Spectrometry

Kütle Spektrometrisi İlkeleri

KEY TERMS AND CONCEPTS

TEMEL TERİMLER VE KAVRAMLAR

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 analyzer has a high transmission rate and is cost-effective, but its low resolution means it does not determine the exact elemental composition of a sample. Its typical resolution is about 1 Da, or 1 u.

A time-of-flight, or TOF, analyzer measures how long ions take to travel from the source through a field-free drift tube to the detector. The flight time is measured in microseconds and converted to an m/z value. Ions enter the tube with about the same kinetic energy, so lighter ions move faster and arrive sooner. That shorter flight time can limit resolution. Resolution can also drop if ions with the same m/z start with different kinetic energies and travel at different speeds.

To improve TOF performance, a reflectron, or ion mirror, can be used. It increases the distance to the detector and slows the ions down. More energetic ions experience a greater slowdown, so the reflectron corrects kinetic energy spread and improves resolution overall. TOF analyzers also offer high sensitivity.

Three-dimensional quadrupole ion-trap analyzers use a ring electrode and two endcap electrodes. A radio-frequency voltage traps the ions so they oscillate in the ring. When the radio-frequency voltage increases, heavier ions become stabilized and are selectively ejected through apertures in the endcaps to the detector. Compared with other mass analyzers that allow only a small fraction of ions to reach the detector, the three-dimensional quadrupole ion trap can send about half of the ions to the detector, which makes it more sensitive. If too many ions are stored, space-charge effects reduce resolution.

Quadrupole, TOF, and Ion Trap Analyzers

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mass analyzers: common types

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...

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key terms and concepts

Learn how quadrupole, TOF, and ion trap mass analyzers separate ions by m/z, and compare their resolution, sensitivity, and detection methods.

Quadrupole, TOF, and Ion Trap Analyzers | JoVE K12

JoVE Core Analitik Kimya, karmaşık kimyasal prensiplerini anlaşılır, ilgi çekici animasyonlara dönüştürerek basitleştirir ve SI Birimlerinden NMR spektroskopisine kadar konuları daha erişilebilir ve anlaşılır hale getirir. Buna ek olarak, bilim insanlarının yer aldığı videolar, bu kavramların dünya çapındaki laboratuvarlarda yürütülen gerçek dünya araştırmalarındaki uygulamalarını gösterir.

analytical chemistry

Quadrupole, TOF, and Ion Trap Analyzers

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