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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: [email protected]
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
4
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
5
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
7
i cng quang
8
Thit bDetectoro Ket qua
Thit b
Bc xa
Vat chat
Tao tia n sac
Ghi tn hieu
i cng quang
9
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
15
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
5
UV-VIS
6
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
7
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
11
UV-VIS
12
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
15
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
25
UV-VIS
26
Phng php t l mol (mole-ratio method)
UV-VIS
27
UV-VIS
28
UV-VIS
29
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