Phổ uv vis

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  • 1. L Nht Tm UIH- IBF Email: tamnhatle@yahoo.com

2. PHNG PHP PH UV-VIS Cc ni dung chnh + Vng ph UV-Vis v ngun gc ca s hp th + Ph UV-Vis + S chuyn dch in t ca cc hp cht hu c + Nhm chc + Cc yu t nh hng n bc sng hp th + H thng thit b quang ph UV-Vis + Cc loi my quang ph + ng dng ph UV-Vis trong phn tch thc phm 3. Vng ph UV-Vis l vng nm cn UV cho n cn IR. c xc nh t khong 180-1100nm. y l vng ph c nghin cu nhiu v c p dng nhiu v mt nh lng. Qu trnh nh lng c tin hnh bng cch o mt vi bc sng hp thu ca hp cht, sau p dng nh lut Lambert-Beer tnh ton. Nhiu th h thit b ra i da trn phng php ny, v ngy cng ti u ha qu trnh. Php ph UV-Vis cn c p dng cng vi cc phng php khc nh Phng Php Sc k trong qu trnh nghin cu. PHNG PHP PH UV-VIS 4. PH UV-VIS V NGUN GC CA S HP TH Vng ph ny thng c chia lm 3 vng ch yu: cn UV (185400 nm), kh kin (400700 nm) v cn hng ngoi (7001100 nm). Ngun gc ca s hp th trong vng ny ch yu l s tng tc ca cc photon ca bc x vi cc ion hay phn t ca mu. S hp th ch xy ra khi c s tng ng gia nng lng photon v nng lng cc in t ngoi cng (ca ion hay phn t) hp th. Kt qu ca s hp th l c s bin i nng lng in t ca phn t. Chnh v vp ph UV-Vis c gi l ph in t 5. PH UV-VIS V NGUN GC CA S HP TH 6. PH UV-VIS S hp th nng lng in t trong vng sng nh sng t ngoi gn (190-400nm) v kh kin (400- 780nm) ca cc cht gy ra s chuyn dch ca cc in t t trng thi c bn sang trng thi kch thch. Biu bin din s tng quan gia cng hp thu theo bc sng ca mt cht c gi l ph UV-Vis ca cht y trong iu kin xc nh 7. Cc quang ph k UV-Vis o truyn quang T hay hp th A ca bc x khi truyn qua mu lng truyn quang T c tnh: Hay : hp th A c xc nh : PH UV-VIS 8. Ty vo trng thi ca mu o m ph thu c c nhng ng nt khc nhau: PH UV-VIS 9. S CHUYN DCH IN T CA CC HP CHT HU C Phn ln cc hp cht hu c c nghin cu trong vng ph UV-Vis. Qu trnh chuyn tip bao gm cc in t , or hay in t n nm trn cc orbital ca cc nguy t nh nh H, C, N, O 10. CHUYN MC * S chuyn v ca e trong lin kt ca cc hp cht hu c t orbital lin kt ln phn lin kt *. S chuyn v ny i hi mt nng lng kh ln, v vy qu trnh chuyn v nm trong vng t ngoi xa ( UV). S CHUYN DCH IN T CA CC HP CHT HU C 11. CHUYN MC n * S chuyn v ca cc in t t obital n ln cc orbital * trong cc nguyn t nh O, N, S . Xy ra vng ph t ngoi gn c cng khng ln. S dch chuyn ny dao ng 180nm cho alcol, dn xut halogen ca n l 190nm. i vi cc amin l 220nm V d : Ete c max= 190nm ( =2000) Metanol c max= 183nm ( =50) Etylamin c max= 210 nm ( =800) S CHUYN DCH IN T CA CC HP CHT HU C 12. CHUYN MC n * y l qu trnh thng xy ra trong phn t c mt nguyn t cha in t khng lin kt nh nhng phn t cha nhm chc cacbonyl (C=O) v bc sng hp thu t 270nm- 295nm. C cng hp thu thp Bn cht ca cc dung mi c nh hng n bc sng hp thu v n tc ng n lin kt trong phn t. S CHUYN DCH IN T CA CC HP CHT HU C 13. CHUYN MC * Cc hp cht ng phn vi etylen cha lin kt i trong phn t c kh nng hp thu mnh trong khong bc sng 170nm V tr hp thu ph thuc vo s hin din ca nhm th v d etylen c max= 165nm ( =16000) Nhng hp cht khng mu thng c ph hp thu trong vng cn t ngoi. Khi chng hp thu bc x th chng s chuyn t orbital cho in t s chuyn ln orbital nhn in t c mc nng lng cao hn. S CHUYN DCH IN T CA CC HP CHT HU C 14. TM TC CC BC CHUYN S CHUYN DCH IN T CA CC HP CHT HU C 15. CHUYN MC d d S chuyn mc xy ra cc orbital d, nht l cc kim loi vng chuyn tip Cc phi t c cp in t t do tham gia lai ha vi nhng orbital ny chuyn in t vo cc orbital ny gy ra s chuyn mc. Mu to ra ca cc phc lm cho phc c kh nng hp thu nhng bc sng vng kh kin S CHUYN DCH IN T CA CC HP CHT HU C 16. CC NHM CHC Nhm chc l nhng nhm nh c to thnh t nhiu nguyn t, quyt nh tnh cht ca hp cht hu c. Ti v tr cc nhm chc trong phn t cc dch chuyn in t xy ra, nn ph ca phn t hu c lin quan ti cc nhm chc trong phn t. Ngi ta tm c cc bc sng hp thu cc i cho tng nhm chc.T c th d on s tn ti ca cc nhm chc thng qua hp thu ca n. 17. NHNG YU T NH HNG TI S CHUYN MC nh hng ca dung mi nh hng ca s lin hp nh hng ca pH 18. NH HNG CA DUNG MI Bc sng hp thu v cng hp thu ca cc hp cht chu nh hng ca dung mi. S tc ng ca nhng dung mi khc nhau ln cc phn t lm thay i mc nng lng gia cc trng thi kch thch v c bn. S tc ng ca dung mi ln phn t lm sinh ra :chuyn dch xanh v chuyn dch NHNG YU T NH HNG TI S CHUYN MC 19. CHUYN DCH XANH L hin tng hp thu bc x ca cc hp cht hu c c bc sng ngn hn trong nhng dung mi c tnh phn cc cao Hin tng tm thy qu trnh chuyn dch n * ca nhm cacbonyl. Nguyn nhn l do s lm bn trng thi n ca dung mi. NHNG YU T NH HNG TI S CHUYN MC 20. NHNG YU T NH HNG TI S CHUYN MC 21. CHUYN DCH L hin tng cc hp cht hu c c xu hng hp thu nhng bc x c bc sng di hn trong nhng dung mi c phn cc cao hn Hin tng c tm thy cc phn t hu c m trong cu trc phn t ca n c s lin hp. NHNG YU T NH HNG TI S CHUYN MC 22. CHUYN DCH Nguyn nhn ca hin tng ny l: + Do khi mch C cng di th hiu ng lin hp cng tng, dn ti lch nng lng gia hai trng thi gim. + Trong phn t hu c c hiu ng lin hp cng di th bc sng hp thu cng ln NHNG YU T NH HNG TI S CHUYN MC 23. CHUYN DCH NHNG YU T NH HNG TI S CHUYN MC 24. TM TC CHUYN DCH XANH V CHUYN DCH NHNG YU T NH HNG TI S CHUYN MC 25. NH HNG CA pH nh hng bn ca phc nh hng n s to phc nh hng dng tn ti NHNG YU T NH HNG TI S CHUYN MC 26. nh hng ca s lin hp S lin hp p- hay - u lm cho trng thi kch thch ca in t * bn hn c nng lng thp hn u ny dn ti bc sng hp thu di hn NHNG YU T NH HNG TI S CHUYN MC 27. THIT B QUANG PH HP THU UV-VIS 28. Ngun sng c nhim v cung cp bc x tng thch vi qu trnh o. Bc x c cung cp bi ngun sng thng l chm bc x a sc, n bao trm mt khong rng ca ph. NGUN SNG 29. + n Tungsten Halogen , l mt ngun sng ph bin dng trong my quang ph. n ny cha mt si dy mnh tungsteng c t trong thy tinh. Khong bc x m n cung cp l t 330 n 900 nm, c dng trong vng visible. +Thi gian s dng n ny khong 1200h. + Vi U= 6v v cng rt ln dy tungten b nung a bu khi tr ( neon, Argon)ln trng thi kch thch v pht bc x TUNGSTEN LAMP 30. n hydrogen or deuterium cung cp bc x trong vng Ultraviolet tng ng vi di bc x t 200 n 450 nm. Trong hai n th n Deuterium n nh hn v c thi gian s dng khong 500h. y l n cho ph lin tc Hydrogen / Deuterium Lamps 31. Hydrogen / Deuterium Lamps 32. Thu nhn chm bc x a sc pht ra t n, v cho bc x n sc i ra.. C hai loi thit b ph bin gm lng knh c cch t THIT B TO BC X N SC 33. Lng knh (Prism) + Nhng bc x c bc sng khc nhau s b b gy nhng gc khc nhau khi i ra khi lng . + Lng knh c th c lm t thy tinh hay thch anh. + Ty thuc vo vt liu lm lng lnh m n c th tch nhng bc x trong vng no (Lng kinh thy tinh ph hp vi cc bc x trong vng visible nhng lng knh thch anh th bao ph c hai vng Ultraviolet v Visible) . THIT B TO BC X N SC 34. + Cch t c cu to vi v s nhng khe rt nh trn mt din tch b mt khong 200 khe trn mt rng 1cm + Ty thuc vo gc ti ca chm nh sng v b mt cch t m hng truyn ca chm bc x khi phn x trn b mt cch t theo nhng hng khc nhau.. CCH T (GRATINGS) THIT B TO BC X N SC 35. CCH T (GRATINGS) Phn loi cch t: + Cch t truyn sut: c lm bng thy tinh + Cch t phn x : Lm bng nhm THIT B TO BC X N SC 36. Quan st ph qua cch t THIT B TO BC X N SC 37. + Khoang hp thu l vng ti nm v tr cui cng ca ng truyn. + Tia bc x n sc sau i c tch ra s i n . Thng c thit k l mt ng nh gi l Cuvettes. + Cuvettes c lm bng nha, thy tinh hay thch anh cha mu o. B PHN CHA MU(CUVETTES) 38. + C tc dng cm nhn bc x in t sau khi b hp th v chuyn lng bc x ny thnh dng in. + Cng dng in thu c l t l thun vi cng bc x p vo b mt catot. + T bo quang in hay ng nhn quang in l nhng thit b hu dng trong vic o xc nh THIT B NHN BIT(DETECTORS) 39. ng nhn quang in c chc nng t hp cc tn hiu chuyn i qua vi giai on khuych i trong thn ca ng. Bn cht ca nguyn liu lm cathode l xc nh nhy ca ph. NG NHN QUANG IN THIT B NHN BIT(DETECTORS) 40. THIT B NHN BIT(DETECTORS) T bo quang in 41. CC LOI MY QUANG PH + My quang ph chm tia n l c pht minh ra u tin, v ton b nh sng i qua mu. + Loi ny l r hn v n c thit k kh n gin C hai loi : My mt chm tia v hai chm tia My mt chm tia 42. u im ca my mt chm tia : Gi thnh thp, thng lng bc x i qua cao v nh vy nhy cao. Nhc im: l c khong lch thi gian khi tin hnh o gia cc chun cng nh mu xc nh, v vy c th c vn vi tri. iu ny xy ra vi nhng thit b c, nhng thit b hin i vi nhng tnh nng cao v n nh khc phc nhc im ny. V vy my quang ph mt chm tia vn c nhng ng dng cao trong cc phng th My mt chm tia CC LOI MY QUANG PH 43. MY QUANG PH DIODE ARRAY CC LOI MY QUANG PH 44. + Thit b o hai chm tia nhm mc ch khc phc tri xy ra trong qu trnh o. Nguyn nhn gy ra tri l cng nh sng b mt i trn ng truyn, do thay i ng i, do phn x, do s chuyn ha thnh dng in khi tng tc vi detector. S mt i ny khng ng nht khi o mu blank v mu o ring bit. + Trong thit b hai chm tia c hai v tr o, tng ng vi mu v mu i chng. Chm tia sng ti c phn tch thnh hai chm c cng bng nhau, mt chm i qua mu o v mt chm i qua mu i chng.. Nh vy I0 v I c o cng mt lc. Double beam CC LOI MY QUANG PH 45. Double beam CC LOI MY QUANG PH 46. u im ca thit b hai chm tia Cho chnh xc cao v mu o v mu i chng c o cng mt lc. Nhc im l gi thnh cao, nhy thp do cu trc quang hc phc tp hn, tin cy thp hn. Double beam CC LOI MY QUANG PH 47. NG DNG PH UV-VIS TRONG THC PHM Phn tch protein Phn tch Carbonhydrat Phn tch hm lng kim loi trong thc phm Phn tch mt s ch tiu nc 48. nh lut Lambert- Beer 49. nh lut Lambert- Beer 50. nh lut Lambert- Beer Mt s sch k hiu K l 51. HIU CHNH 52. SAI LCH TRONG L LAMBERT - BEER nh lut ch ng vi nhng dung dch c nng l thp Do ngun sng khng tht l n sc nn c ln nhng bc x c bc sng ln cn nhim vo. Dn ti A= lg I/I0 khng ng