Instrumental AnalysisCc phng php phn tch Ha l (Instrumental Analysis)M mn hc: 6020023 tn ch (2 l thuyt v 1 th nghim) Mn tin quyt: Ha Phn tchGing vin: Trn Th Kiu Anh Phng TN Ha Phn tch, 207 B2 B mn K thut Ha l E-mail: ttkanh@hcmut.edu.vn

M u

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M u

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Cc phng php phn tch Ha lMc tiuPhng php phn tch dng c (nh tnh v nh lng) Xy dng phng php phn tch thch hp cho tng i tng phn tch

Ti liu tham khoPhn tch nh lng, Nguyn Th Thu Vn, HQG TP. HCM Th nghim Phn tch nh lng, Nguyn Th Thu Vn, Trn Th Minh Hiu, Nguyn Duy Khim, L Xun Mai, Nguyn Bch Tuyt, HQG TP. HCM Bi tp v S tay Phn tch nh lng, Nguyn Th Thu Vn, HQG TP. HCM Analytical chemistry, Gary D. Christian, 6th edition, John Wiley & Sons, 2004.

Yu cu i vi sinh vinc trc bi ging, sch tham kho v lm bi tp sau mi chng

Ni dung nh gi

T luan va trac nghiem

Kim tra gia hc k (45): 30% Kim tra cui k (90): 70%M u3

M u

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Ni dung2

Ni dungNhm pp tch4 Sc k n

Nhm pp ph nghimPh t ngoi kh kin (UV/VIS) Ph hng ngoi (IR) Khi ph (MS) Ph cng hng t ht nhn (NMR)M u

Ph nguyn t1

Nhm pp in3

PP in khi lng PP pt da vo o th PP VoltAmpere

gin

5 6 7

Sc k kh (GC) Sc k lng (HPLC)

Chng 1: i cng v cc phng php phn tch quang Chng 2: Ph t ngoi kh kin (UV-VIS) Chng 3: Ph hng ngoi (IR) Chng 4: Ph nguyn t Chng 5: Khi ph (MS) Chng 6: Ph cng hng t (NMR) Chng 7: i cng v cc phng php phn tch in ha Chng 8: Phng php in khi lng Chng 9: Phng php phn tch da vo vic o th6

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M u

Ni dung (tt)Chng 10: Phng php Volt-Ampere Chng 11: i cng v phng php sc k Chng 12: Sc k n gin Chng 13: Sc k kh Chung 14: Sc k lng

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i cng cc phng php phn tch quang i cng cc phng php phn tch quangNguyn tc Bc x in t Tng tc gia bc x v vt cht nh lut Lamber-Beer

i cng quang

1

i cng quang

2

Nguyn tc

Bc x in t (Electromagnetic radiation)Bn chtnh tnh nh lng ?

Bc x

i tng nghin cu(Hp thu hay Pht x)

Tnh cht sng Tnh cht ht

Phng truyen

Cc i lng c trngwavelength (cm, m, nm, A) frequency (s 1) the velocity of light c c = . = 3 x 10 10 cm/s wavenumber (cm 1) = 1/ = /c3

The energy of a unit of radition (photon)

E = h = hc/ = h.c. E (eV, kcal/mol) h: hng s Planck = 6,626.10 34 J.s = 6,626.10 27 erg.s = 6,59 eV.s4

i cng quang

i cng quang

Cc vng bc x in t (electromagnetic spectrum)UV-VIS IR NMR

Cc vng mu ca bc xWavelength Absorbed (nm) 400-430

Absorbed color Violet Blue Green-blue Green Green-yellow Yellow Orange Red

Transmitted color (Complement) Yellow-green Yellow-orange Red Red-Violet Violet Blue Blue-green Green6

(Gamma rays)

X rays

Ultraviolet

Visible

Infrared

Radio waves

430-490 490-510 510-530 530-560 560-590 590-6105

Violet 380 nm

Blue

Green

Yellow

Orange

Red 760 nm

E = h = hc/ = hc

Bc sng ngn, nng lng cao NMR: Nuclear Magnetic Resonance

i cng quang

i cng quang

610-730

Ni nng ca vt chtNang lng

v 3 v 2 v1 v 0 v3 v2 v1 v0

Trang thai electron (The excited state) kch thch

E1

Ni nng ca vt cht

hTrang thai electron c ban

J 0

(The ground state)

E0

JJ o1

J2

Cac trang thai nang lng cua phan t hai nguyen t

Et : Nng lng in t (electron energy) Ed: Nng lng dao ng (vibration energy) Eq: Nng lng quay (rotation energy)i cng quang

E = Et + Ed + Eq Et = E1 E0

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i cng quang

8

Thit bDetectoro Ket qua

Thit b

Bc xa

Vat chat

Tao tia n sac

Ghi tn hieu

i cng quang

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i cng quang

10

Thit b

Thit b

i cng quang

11

i cng quang

12

Thit b

Thit b

i cng quang

13

i cng quang

14

Thit b

Ph UV-VIS

i cng quang

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i cng quang

16

PH IR

nh lut Lamber-BeerIR

I

o

I

A

I

T

IO = IR + IA + IT = IA + IT (b mt chu o nhn)

truyn sut T (Transmittance) T = IT/Io hay T% = 100 x IT/Io

hp thu A (Absorbance) A = log I0/IT = log 1/T = log 100/ T% = 2 log T%

i cng quang

17

i cng quang

18

nh lut Lamber-BeerIR

Tng tc gia bc x v vt chtIA IT

A=bC

Io

H s hp thu mol, (L x mol -1 x cm -1) b: b dy cuvet o C: nng cu t, mol/L H s hp thu ring, (L x g C: nng cu t, g/L-1

Vt cht v cc bc x in t trao i nng lng c tnh cht gin on (E = n h, n = 0, 1, 2) S hp thu lm thay i cng (mt cc ht photon) ca bc x in t m khng lm thay i nng lng (E = h = hc/) ca bc x in t

x cm -1)I I0 I

Ty thuc bn cht cu t, di sng o, toi cng quang19

?i cng quang

?

20

UV-VIS Ph t ngoi-kh kin (UV-VIS spectrometry) Ph kch thch electronC s l thuyt S hp thu bc x UV-VIS ca hp cht v c v phc cht S hp thu bc x UV-VIS ca hp cht hu c K thut thc nghim v ng dng

UV-VIS

1

UV-VIS

2

Cc vng bc x in t (electromagnetic spectrum)UV-VIS IR NMR

Cc vng mu ca bc xWavelength Absorbed (nm) 400-430

Absorbed color Violet Blue Green-blue Green Green-yellow Yellow Orange Red

Transmitted color (Complement) Yellow-green Yellow-orange Red Red-Violet Violet Blue Blue-green Green4

(Gamma rays)

X rays

Ultraviolet

Visible

Infrared

Radio waves

430-490 490-510 510-530 530-560 560-590 590-6103

Violet 380 nm

Blue

Green

Yellow

Orange

Red 760 nm

E = h = hc/ = hc

Bc sng ngn, nng lng cao NMR: Nuclear Magnetic Resonance

UV-VIS

UV-VIS

610-730

Ni nng ca vt chtNang lng

Thit bDetector E1Ket qua o

v 3 v 2 v1 v 0 v3 v2 v1 v0

Trang thai electron (The excited state) kch thch

hTrang thai electron c ban

J 0

(The ground state)

E0

Bc xa

Vat chat

J2 JJ o1

Tao tia n sac

Ghi tn hieu

Cac trang thai nang lng cua phan t hai nguyen t

Et : Nng lng in t (electron energy) Ed: Nng lng dao ng (vibration energy) Eq: Nng lng quay (rotation energy)UV-VIS

E = Et + Ed + Eq Et = E1 E0

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UV-VIS

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Ph UV-VIS

nh lut Lamber-BeerIR IA IT

Io

IO = IR + IA + IT = IA + IT (b mt chu o nhn)

truyn sut T (Transmittance) T = IT/Io hay T% = 100 x IT/Io

hp thu A (Absorbance) A = log I0/IT = log 1/T = log 100/ T% = 2 log T%

UV-VIS

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UV-VIS

8

nh lut Lamber-BeerIR

nh lut Lamber-BeerIA IT

A=bC

Io

H s hp thu mol, (L x mol -1 x cm -1) b: b dy cuvet o C: nng cu t, mol/L H s hp thu ring, (L x g -1 x cm -1) C: nng cu t, g/L

Ty thuc bn cht cu t, di sng o, toUV-VIS9

UV-VIS

10

Gii hn nh lut Lamber-Beernh sng qua mu khng hon ton n sc nh hng ca dd kho st (pha long, bn ca dd o, nng dd...)

Nhng yu t nh hng cng hp thuVn hnh my (to bc x n sc, chn bc x, K thut o Bn cht ddNng dd nh hng do pha long, hay do pH nh hng ca thi gian nh hng ca cc dng phcgi nhit c nh, chn cuvet o, tng b dy dd, loi nh hng cu t ph)

UV-VIS

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UV-VIS

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ng dngnh lngDd 1 cu t Dd 2 cu t

nh lng dd cha 1 cu t(1) A = bc. Bit A, , b. Tnh C. (2) Ac = bCc, Am = bCm ; Am/ Ac = Cm/Cc Cm = Cc x Am/Ac (3) Am = bCm, Am = b(Cm + Cc); Am- Am = bCc ; Am/ Am - Am = Cm/C Cm = Cc x Am/ Am - Am (4)A(M1) A(M0)

PP chun quang Kim tra tinh khit Nhn bit cu trc Xc nh hng s phn ly acid-baz Xc nh thnh phn phc cht

C0AA5 A4 A3 A2 A1 C1

C1 A1

C2 A2

C3 A3

C4 A4

C5 A5

M0 A(M0)

M1 A(M1)

A0

Cm

UV-VIS

13

UV-VIS

C2 C3 C4

C5

C, mol/L14

UV-VIS

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UV-VIS

16

Cn bng nhiuM + OH + L + H+ ML + L ML2

Dung dch hai cu tCn bng chnh[ ML] 103 [ M ]'

M (OH )1 ,...HL

Cn bng nhiu c mu[ ML2 ] 10 3 [ ML]

Cn bng to ta[ M (OH ) x ] 10 3 [M ]UV-VIS17

UV-VIS

18

Dung dch hai cu tmax ca tng cu t cch xa nhau max ca tng cu t gn nhau (p dngI II I II A1 = A1 + A1 = 1 bC I + 1 bC II I II I II A2 = A2 + A2 = 2 bC I + 2 bC II

Dung dch 2 cu t - V d

tnh cht cng hp thu)

CI = C =II

II II A2 1 A1 2 I II I II 2 1 1 2

II A2 1 A1 2 II I II I II 2 1 1 2

UV-VIS

19

UV-VIS

20

Dung dch 2 cu t - V d

Xc nh hng s phn ly ca 1 acid yuHA H+ + A Pha 1 dung dch c nng HA bit trc iu chnh pH dd acid o A ca dd ti max iu chnh pH dd baz o A ca dd ti max o pH dd ti pH trung gian no ti cc bc sng max tng ng Tnh nng [A-], [HA]. Bit pH, tnh c K HIn22

[ H + ][ A ] K HA = [ HA] [ HA] [ H + ] = K HA [A ] [ A ] pH = pK HA + lg [ HA]UV-VIS21

UV-VIS

UV-VIS

23

UV-VIS

24

Xc nh thnh phn phc cht

Phng php bin s lin tc (continuous variations)

UV-VIS

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UV-VIS

26

Phng php t l mol (mole-ratio method)

UV-VIS

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UV-VIS

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UV-VIS

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UV-VIS

30

Ph UV-VIS trong phn tch cu trc phn t

Mt s thut ngNhm mang mu (chromophores) nhm nguyn t c cha electron lnh trch nhim hp thu bc x Mt s nhm mang mu quan trng:Conjugated double bondsO

Aromatic systems

NUV-VIS31

UV-VIS

32

Mt s thut ngNhm tr mu (auxochrome) nhm c t nht mt cp electron n, to lin hp vi lin kt ca nhm mang mu (-SH, -NH2, OH) Hiu ng trng sc (bathochromic effect) hay chuyn dch (red shift) s chuyn gi tr max v pha c bc sng di hn Hiu ng cn sc (hypsochromic effect) hay chuyn dch xanh (blue shift) s chuyn gi tr max v pha c bc sng ngn hn

Mt s thut ngHiu ng m mu (heperchromic effect) hiu ng dn n s tng cng hp thu (tng gi tr ) Hiu ng nht mu (hypochromic effect) hiu ng dn n s gim cng hp thu (gim gi tr )

UV-VIS

33

UV-VIS

34

Hp thu ca cc photon* n* Forbidden Transitions, thp) n * * Medium to strong molar absorptivity.

Molecular Orbitals

EnergyAtomic orbital

Unoccupied levels

n

Atomic orbital

Occupied levels

Molecular orbitalsUV-VIS UV-VIS

35

36

An Electronic Transition

orbitals

* orbitalenergy gap E = habsorb quantum of light of frequency

* orbital

C

C

C

C

C

C

orbital ground (bonded) stateUV-VIS

orbital excited state2p 2p

bonding orbital

* antibonding orbital

similar in energy to the unbonded state37

UV-VIS

38

orbitals

* orbitals are lower in energy than ** *2p 2s 2p C 2p 2s

C

C

CC

*2p

C C C

UV-VIS

39

UV-VIS

40

Non-Bonding Electrons in >C=O* *2p 2s n 2p 2s

S hp thu ca phn t hu cE

* Orbital phn t phn lin kt Orbital nguyn t Orbital phn t lin kt

C

O

E

* n - * n-* * n

S phn b nng lng - * > n - * > - * > n - *V du - * (150 nm) n - * (150 200 nm) - * (200 300 nm) n - * (> 300 nm)42

- * -*

UV-VIS

41

UV-VIS

Most Important TransitionsIncreasing energy

Absorption of Simple Unconjugated ChromophoresChromophore

* * * n * n *

In alkanes In carbonyl compounds In alkenes, carbonyl compounds, alkynes, azo compounds and so on In oxygen, nitrogen, sulfur and halogen compounds In carbonyl compounds

-bonded electronsC-C and C-H

Notation of transition *

max(nm) ~150 quan st c trong ph UV

-O-N< -S>C=O >C=O

lone pair electrons

n n n n n

* * * * *

~185 ~195 ~195 ~300 ~190

-bonded electrons >C=C< (isolated) * >C=O *UV-VIS43

~190 ~19044

UV-VIS

Conjugated Systems Absorb at Longer Wavelength

Conjugated Systems Absorb at Longer Wavelength

4* * A isolated double bond B 2 1 two conjugated double bondsHOMO - highest occupied molecular orbital

3*

LUMO - lowest unoccupied molecular orbital

UV-VIS

45

UV-VIS

46

Conjugated Systems Absorb at Longer Wavelength

Chn dung mi (Solvent)Dung mi khng hp thu trong vng bc sng phn tch Dung mi khng to phc vi cht phn tch nh hng ca dung mi ln cu trc phn t.

UV-VIS

47

UV-VIS

48

Dung miSolvent Lower wavelength limit (nm) 205 210 210solvents of choice - no significant interference

nh hng ca dung minh hng ln bc sng hp thu cc i (max) v hp thu mol (the molar absorptivity (max)) do:pH Polarity Electrolyte concentration

UV-VIS

Water Ethanol Hexane Cyclohexane Methanol Diethyl ether Acetonitrile Tetrahydrofuran Dichloromethane Chloroform Carbon tetrachloride Benzene

210 210 210 235 245 280

210 220

26549

UV-VIS

50

nh hng ca dung mi

Kt lunAlkanes, alcohols v ethers khng quan st c trong ph UV ( * v n*) Ketones weak band (n* transitions) , quan st c trong ph UV Dienes v enons : strong band (* absorptions), quan st c trong ph UV

UV-VIS

51

UV-VIS

52