Slide 1

1 The Mass SpectrumPresentation of data

Spektrum massa disajikan dalam hal kelimpahan ion vs m / e ratio (massa). Ion yang paling banyak terbentuk pada ionisasi menimbulkan puncak tertinggi pada spektrum massa - ini adalah puncak dasar.

base peak, m/e 43

2

M+, m/e 114Presentation of data

3. All other peak intensities are relative to the base peak as a percentage.4. If a molecule loses only one electron in the ionization process, a molecular ion is observed that gives its molecular weight this is designated as M+ on the spectrum.

3

fragment ionsPresentation of data

5. Dalam kebanyakan kasus, ketika molekul kehilangan elektron valensi, ikatan yang rusak, atau ion yang terbentuk cepat fragmen untuk menurunkan ion energi 6. Massa ion bermuatan dicatat sebagai fragmen ion dengan spektrometer - fragmen netral tidak tercatat!

4 B. Determination of Molecular Mass

Ketika puncak M + diamati memberikan massa molekul dengan asumsi bahwa setiap atom dalam bentuk isotop yang paling melimpah2. Ingat karbon yang merupakan campuran dari 98,9% 12C (massa 12), 1,1% 13C (massa 13) dan S, O, p bond, R > Cl > Br > IThe sequence of i-cleavage tendency:halogen > O, S >> N, C

15Compounds without heteroatoms ( s-cleavage)

Examples:a-cleavage

i-cleavage

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Examples:

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Loss of small molecules, such as H2O, CO, C2H4

18G. Patterns of different organic compounds fragmentationSaturated hydrocarbons1. Alkanes

Figure 1 Mass spectrum of dodecane.Dodecane

192. Branched Alkanes

Figure 2 Mass spectrum of 5-methylpentadecane.

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Figure 3 Mass spectrum of 4-methylundecane.4-methylundecaneFigure 4 Mass spectrum of 2,2,4,6,6-pentamethylheptane.

213. Cycloalkanes

Figure 5 Mass spectrum of cyclohexane.

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Figure 6 Mass spectrum of 1-methyl-3-pentylcyclohexane.1-methyl-3-pentylcyclohexane

23Aromatic hydrocarbons

Figure 7 Mass spectrum of 1-phenylhexane

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Process of fragmentations:25

Alcohols, Phenol and Ether1. AlcoholFigure 8 Mass spectrum of 1-dodecanol

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Process of fragmentations:

272. Phenol

283. Ether

Figure 9 Mass spectrum of hexyl ether.

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Ketone and Aldehyde Figure 10 Mass spectrum of 2-dodecanone.

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Figure 11 Mass spectrum of octanal .

31Carboxylic acid

32Ester

Figure 12 Mass spectrum of hexyl benzoate.

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Other compounds Figure 13 Mass spectrum of 1-chlorododecane.

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Figure 14 Mass spectrum of 1-bromododecane.

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Figure 15 Mass spectrum of N-isopropyl-N-methylbutan-1-amine

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Figure 16 Mass spectrum of N-ethylcyclopentamine.

37Figure 17 Mass spectrum of methyl octanoate.

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Exercise 1:HRMS menunjukkan massa tepat senyawa A adalah 136.0886 dan rumus ini senyawa C9H12O, silahkan konfirmasi struktur senyawa A.AnswerDEB: = (2*9+2-12)/2 = 4m/z: 118 M-18 M-H2O -OH39, 51, 77 107 M-29 M-C2H5-C2H5

39Exercise 2:Please confirm the structure of compound A.

I158 = 13%I157 = 3.7%I156 = 41%40Answer1. I156/I158 = 3/1Containing one Cl atom2. Nc = 3.7/411.1%8 Containing eight C atoms3. m/z: 39, 51, 77

; 94

107

4. 156-35-77-16-14 = 14CH2

41Exercise 3:

Berdasarkan spektrum massa EI senyawa A, silakan menulis proses fragmentasi42

Answer