《有機(jī)波譜分析雙語課件 (1).pdf》由會(huì)員分享，可在線閱讀，更多相關(guān)《有機(jī)波譜分析雙語課件 (1).pdf（16頁珍藏版）》請(qǐng)?jiān)趨R文網(wǎng)上搜索。

1、質(zhì)譜介紹 有機(jī)波譜分析 Organic Spectroscopic Analysis Introduction to Mass Spectrometry Introduction to Mass Spectrometry（MS,質(zhì)譜）MS can be considered as a precise balance（精密天平）It weights ions in the gas phase（氣相離子）and determines the masses of individual atoms and molecules.1.What is the Mass Spectrometry（質(zhì)譜）?3

2、So What is Mass Spectrometry?John B.Fenn,the originator of electrospray ionization for biomolecules and the 2002 Nobel Laureate in Chemistry,probably gave the most apt answer to this question:Mass spectrometry is the art of measuring atoms and molecules to determine their molecular weight.Such mass

3、or weight information is sometimes sufficient,frequently necessary,and always useful in determining the identity of a species.MS in history Source:Wikipedia The Manhattan project during the Second World War Atomic bombs（原子彈）The most critical material in nuclear bomb is U235（an isotope U238）鈾同位素.Used

4、 a mass spectrometer（質(zhì)譜儀）to separate U235 from U238.MS in history The Manhattan Project designed a mass spectrometer to separate U235+from U238+.6 1886:E.Goldstein discovered anode rays(positive gas ions)in gas discharge.1897:J.J.Thomson discovered the electron and determined its m/z ratio.Nobel Pri

5、ze in 1906.1898:W.Wien analyzed the anode rays by magnetic deflection,and established that they carry a positive charge.Nobel Prize in 1911.1909:R.A.Millikan&H.Fletcher determined the elementary unit of charge.History of Mass Spectrometry-Pre-MS 7 1897,discovery of electron J.J.Thomson,1856-1940,Bri

6、tish Scientist Francis William Aston 1922 Nobel Prize in Chemistry “for his discovery,by means of his mass spectrograph,of isotopes,in a large number of non-radioactive elements,and for his enunciation of the whole number rule.”10 Joseph John Thomson 1906 Nobel Prize in Physics Francis William Aston

7、 1922 Nobel Prize in Chemistry Wolfgang Paul 1989 Nobel Prize in Physics John B.Fenn 2002 Nobel Prize in Chemistry Koichi Tanaka 2002 Nobel Prize in Chemistry Nobel Prize Winners for Mass Spectrometry Ion trap isotope 12 Basics of Mass Spectrometry A mass spectrometer determines the mass of a molecu

8、le by measuring the mass-to-charge ratio(m/z)of its ion.Ions are generated by inducing either the loss or gain of a charge from a neutral species.Once formed,ions are electrostatically directed into a mass analyzer where they are separated according to m/z and finally detected.The result of molecula

9、r ionization,ion separation,and ion detection is a spectrum that can provide molecular mass and even structural information.13 Basics of Mass Spectrometry Over the past decade,mass spectrometry has undergone tremendous technological improvements allowing for its application to proteins,peptides,carb

10、ohydrates,DNA,drugs,and many other biologically relevant molecules.Due to ionization sources such as electrospray ionization and matrix-assisted laser desorption/ionization(MALDI),mass spectrometry has become an irreplaceable tool in the biological sciences.Fragmentation in MS 1.靈敏度高，樣品用量少。目前有機(jī)質(zhì)譜儀的絕

11、對(duì)靈敏度可達(dá)50pg（pg為1012g），無機(jī)質(zhì)譜儀絕對(duì)靈敏度可達(dá)1014g。It is the method of choice for the analysis of trace materials as pesticide residues and drugs and their metabolites,especially in forensic and medical research;it is important in bringing cheating athletes to heel!Characteristics of Mass Spectrometry 2.快速、直觀、適用性廣、應(yīng)用范圍寬；3.可以有效地與多種色譜技術(shù)聯(lián)用，如 GC/MS,LC/MS,CE/MS等；自身的串聯(lián) MS-MS 4.在鑒定有機(jī)物的四大重要手段（NMR、MS、IR、UV）中，質(zhì)譜是唯一可以確定分子式的方法。In the numerous applications of mass spectrometry,frequently the single most important requirement is to obtain a molecular weight!Characteristics of Mass Spectrometry