masena spektrometrija 2010
TRANSCRIPT
![Page 1: Masena spektrometrija 2010](https://reader031.vdocuments.net/reader031/viewer/2022012403/5571f95d49795991698f6863/html5/thumbnails/1.jpg)
Masena spektrometrija (MS)
![Page 2: Masena spektrometrija 2010](https://reader031.vdocuments.net/reader031/viewer/2022012403/5571f95d49795991698f6863/html5/thumbnails/2.jpg)
Identifikacija i odre đivanje Mr organskih jedinjenja
• Tačnost:• Za velike biomolekule 0.01%Za molekul od npr. 40 000 Da, greška je
4 Da• Za male molekule, ta čnost 5 ppm• Dovoljno da se sa sigurnoš ću napiše
molekulska formula jedinjenja
![Page 3: Masena spektrometrija 2010](https://reader031.vdocuments.net/reader031/viewer/2022012403/5571f95d49795991698f6863/html5/thumbnails/3.jpg)
Princip MS
• Od molekula napraviti molekulske (molekularne) jone
• Molekulski joni se raspadaju na druge jone-fragmente
• Svi joni skre ću u magnetnom ili elektri čnom polju u zavisnosti od
m/z (mass-to-charge ratio)
• Zapis svih jona čini maseni spektar
![Page 4: Masena spektrometrija 2010](https://reader031.vdocuments.net/reader031/viewer/2022012403/5571f95d49795991698f6863/html5/thumbnails/4.jpg)
Osnovni delovi masenog spektrometra
• Jonski izvor - gde se stvaraju joni od analiziranih molekula
• Maseni analizator (maseni filter)- gde se analizirani joni razdvajaju u zavisnosti od mase (m/z)
• Detektor i sistem za obradu podataka(kompjuter sa bazom podataka)
![Page 5: Masena spektrometrija 2010](https://reader031.vdocuments.net/reader031/viewer/2022012403/5571f95d49795991698f6863/html5/thumbnails/5.jpg)
Blok shema MS
Nacrtati:Nacrtati:
![Page 6: Masena spektrometrija 2010](https://reader031.vdocuments.net/reader031/viewer/2022012403/5571f95d49795991698f6863/html5/thumbnails/6.jpg)
Jonski izvori(Ionisation Modes)
1. Elektronsko bombardovanje (Electron impact- EI)
2. Hemijska jonizacija (Chemical ionisation-CI)3. Fast Atom Bombardment ( FAB)4. Plasma Desorption Ionisation (PDI)5. Matrix-Assisted Laser Desorption Ionisation
(MALDI )6. Electrospray Ionisation (ESI)7. Ion Spray Ionisation (ISI)
![Page 7: Masena spektrometrija 2010](https://reader031.vdocuments.net/reader031/viewer/2022012403/5571f95d49795991698f6863/html5/thumbnails/7.jpg)
Elektronsko bombardovanje
• Komora : usijana katoda od W ili Ru emituje elektrone ka anodi
• E= 70 eV, za jonizaciju dovoljno 13 eV• Elektroni se sudaraju sa molekulima
uzorka : M + e- →→→→M+ + 2e-
• Molekularni jon : M+ je nestabilan i raspada se na fragmente:
• M+→→→→F1+F2+F3+...
![Page 8: Masena spektrometrija 2010](https://reader031.vdocuments.net/reader031/viewer/2022012403/5571f95d49795991698f6863/html5/thumbnails/8.jpg)
Molekularni i fragmentni joni
![Page 9: Masena spektrometrija 2010](https://reader031.vdocuments.net/reader031/viewer/2022012403/5571f95d49795991698f6863/html5/thumbnails/9.jpg)
Hemijska jonizacija (“nežna ili meka”jonizacija)
• Uzorak jonizuje reagens gas: metan, amonijak, izobutan
• 2 CH4 + 2e-→→→→CH4+ + CH3
+ + H•••• +4e-
• CH4+ + CH4 →→→→CH5
+ +CH3••••
• CH3+ + CH4 →→→→C2H5
+ +H2
![Page 10: Masena spektrometrija 2010](https://reader031.vdocuments.net/reader031/viewer/2022012403/5571f95d49795991698f6863/html5/thumbnails/10.jpg)
M + CH5+→→→→MH+ + CH4
M + C2H5+→→→→MH+ + C2H4
MH+-kvazimolekulski jon
M veće za 1 od molekulskog jona
![Page 11: Masena spektrometrija 2010](https://reader031.vdocuments.net/reader031/viewer/2022012403/5571f95d49795991698f6863/html5/thumbnails/11.jpg)
Maseni analizatori (filtri)
1. Magnetni analizator (magnetni sektor)
2. Kvadripolni maseni analizator3. Time-of- flight (TOF) analysers4. Ion ciklotron resonance Fourier
transform MS (FTMS)5. Ion trap analyser
![Page 12: Masena spektrometrija 2010](https://reader031.vdocuments.net/reader031/viewer/2022012403/5571f95d49795991698f6863/html5/thumbnails/12.jpg)
Magnetni sektor
![Page 13: Masena spektrometrija 2010](https://reader031.vdocuments.net/reader031/viewer/2022012403/5571f95d49795991698f6863/html5/thumbnails/13.jpg)
R konstantno- menja se H, a ne V
2
mzV
2υ=
R
mHz
2υ=υ V2
RH
z
m 22
=
![Page 14: Masena spektrometrija 2010](https://reader031.vdocuments.net/reader031/viewer/2022012403/5571f95d49795991698f6863/html5/thumbnails/14.jpg)
MS sa magnetnim sektorom
![Page 15: Masena spektrometrija 2010](https://reader031.vdocuments.net/reader031/viewer/2022012403/5571f95d49795991698f6863/html5/thumbnails/15.jpg)
Magnetni analizatori su najbolji, ali i najskuplji...
• Rezolucija- mera razdvojenosti dva pika
• Dobra rezolucija preko 10 000 (200,00 od 200,02 Da)
• Loša rezolucija ispod 1 000
M
Mzolucija
∆=Re
M-masa jona∆∆∆∆M-razlika u masi
između M i susednog jona
![Page 16: Masena spektrometrija 2010](https://reader031.vdocuments.net/reader031/viewer/2022012403/5571f95d49795991698f6863/html5/thumbnails/16.jpg)
Kvadrupolni maseni analizator
![Page 17: Masena spektrometrija 2010](https://reader031.vdocuments.net/reader031/viewer/2022012403/5571f95d49795991698f6863/html5/thumbnails/17.jpg)
• Pogodni za rutinska ispitivanja:• Mali primenjeni potencijali:5-30 V• Nisu glomazni• Jeftini• Iako je rezolucija mala (ispod 800),
pogodni za brza skeniranja
![Page 18: Masena spektrometrija 2010](https://reader031.vdocuments.net/reader031/viewer/2022012403/5571f95d49795991698f6863/html5/thumbnails/18.jpg)
Detektori (truba)
• Elektronski multiplikator
![Page 19: Masena spektrometrija 2010](https://reader031.vdocuments.net/reader031/viewer/2022012403/5571f95d49795991698f6863/html5/thumbnails/19.jpg)
Maseni spektar je lična karta svakog jedinjenja
• “Fingerprint ”- otisak prsta
• Molekul se uvek raspada na fragmente na isti način(pod istim uslovima)
![Page 20: Masena spektrometrija 2010](https://reader031.vdocuments.net/reader031/viewer/2022012403/5571f95d49795991698f6863/html5/thumbnails/20.jpg)
Maseni spektar-niz pikova
• Apscisa: m/z (z je naj češće 1, znači molekulska masa)
• Ordinata: Relative abundance, Relative intensity
• Intenzitet pika je direktno proporcionalan vremenu života jona
• Stabilan jon traje duže-intenzivniji pik
![Page 21: Masena spektrometrija 2010](https://reader031.vdocuments.net/reader031/viewer/2022012403/5571f95d49795991698f6863/html5/thumbnails/21.jpg)
Najintenzivniji pik -osnovni ili bazni pik
• Najčešće nije molekularni jon• Visokoenergetski molekuli su
nestabilni i kratkoživu ći• Ne traju dovoljno dugo da stignu do
detektora
Molekulski pik-najvažniji za analizu!
![Page 22: Masena spektrometrija 2010](https://reader031.vdocuments.net/reader031/viewer/2022012403/5571f95d49795991698f6863/html5/thumbnails/22.jpg)
Hajde da tumačimo masene spektre...H2O + 1e
- →→→→ [[ H2O ]]++ + 2 e+ 2 e--
1 = H1 = H++ 16 = O16 = O++ 17 = [OH]17 = [OH]+ + 18 = [H18 = [H22O]O]++
![Page 23: Masena spektrometrija 2010](https://reader031.vdocuments.net/reader031/viewer/2022012403/5571f95d49795991698f6863/html5/thumbnails/23.jpg)
Maseni spektar metanola CH3OH
![Page 24: Masena spektrometrija 2010](https://reader031.vdocuments.net/reader031/viewer/2022012403/5571f95d49795991698f6863/html5/thumbnails/24.jpg)
![Page 25: Masena spektrometrija 2010](https://reader031.vdocuments.net/reader031/viewer/2022012403/5571f95d49795991698f6863/html5/thumbnails/25.jpg)
![Page 26: Masena spektrometrija 2010](https://reader031.vdocuments.net/reader031/viewer/2022012403/5571f95d49795991698f6863/html5/thumbnails/26.jpg)
Neki karakteristični fragmenti
![Page 27: Masena spektrometrija 2010](https://reader031.vdocuments.net/reader031/viewer/2022012403/5571f95d49795991698f6863/html5/thumbnails/27.jpg)
Kako se raspada kokain?
![Page 28: Masena spektrometrija 2010](https://reader031.vdocuments.net/reader031/viewer/2022012403/5571f95d49795991698f6863/html5/thumbnails/28.jpg)
Maseni spektar kokaina dobijen elektronskim bombardovanjem
![Page 29: Masena spektrometrija 2010](https://reader031.vdocuments.net/reader031/viewer/2022012403/5571f95d49795991698f6863/html5/thumbnails/29.jpg)
Maseni spektar kokaina dobijen hemijskom jonizacijom
![Page 30: Masena spektrometrija 2010](https://reader031.vdocuments.net/reader031/viewer/2022012403/5571f95d49795991698f6863/html5/thumbnails/30.jpg)
Maseni kao detektorKombinacije:
GC-MS, HPLC-MS, CE-MS MS-MS
• Moćni gasno-maseni
![Page 31: Masena spektrometrija 2010](https://reader031.vdocuments.net/reader031/viewer/2022012403/5571f95d49795991698f6863/html5/thumbnails/31.jpg)
Koichi Tanaka
• Nobel Prize in Chemistry 2002"for the development of soft desorptionionisation methods for mass spectrometricanalyses of biological macromolecules"
![Page 32: Masena spektrometrija 2010](https://reader031.vdocuments.net/reader031/viewer/2022012403/5571f95d49795991698f6863/html5/thumbnails/32.jpg)
MALDI