UV-VIS Spectroscopy.ppt

8/16/2019 UV-VIS Spectroscopy.ppt

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ULTRAVIOLET AND VISIBLE

SPECTROSCOPYChap 6&7-T1Chap 1-T2

Chap 13&14-R1


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•when a molec le !" " #$ec%e %o '( )o* (!"+*a !a%!on %*an"!%!on" o, alence elec%*on" occ *" !%he molec le.

•!.e e/c!%a%!on o, an elec%*on ,*om a ,!llemolec la* o*#!%al %o %he ne/% h!0he* ene*0 o*#!%

•"!nce '( ene*0 !" an%! e %he a#"o*p%!on"pec%* m a*!"!n0 ,*om a "!n0le elec%*on!c %*an"!%!o

"ho l con"!"% o, "!n0le !"c*e%e l!ne.• # % e %o " pe*!mpo"!%!on o, *o%a%!onal an

!#*a%!onal " #le el a !"c*e%e l!ne ne e* o#%a!n"


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A#"o*#ance A o, a "ample !" e,!ne

a"5 A = -log 10 T = log P 0 / P= ε c l whe*e

P o = intensity of incident !di!tion ene gy

P = intensity of t !ns"itted !di!tion ene gy

c = "ol! concent !tion of sol#te

l = inte n!l lengt$ of t$e cell

=

L!"%e t-Bee l!( 5 o* monoch*oma%!c*a !a%!on a#"o*#ance !" !*ec%l p*opo*%!onal %o %he&!t$lengt$ an %heconcent !tion o, %hea#"o*#!n0 "pec!e".


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)ol! !%so &ti'ity/)ol! e*tinctioncoefficient 5

• !, %he concen%*a%!on o, "pec!e" !" e/p*e""e !n"ol! concent !tion an pa%hlen0%h !" !ncenti"ete * %he con"%an% !" c a"ol! e*tinctioncoefficient

• 8%" n!% 9 l!%e* mole-1cm -1 an !% !" con"%an% ,o* a

0! en a#"o*#!n0 molec leo* :o !ne Se* m Al# m!n):SA+

; 2 96.67


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+e'i!tion f o" BL l!( 5 ,all !n%o 3 ca%e0o*!e"5

1. Real e !a%!on5A% h!0h concen%*a%!on

- %he a e*a0e !"%ance #e%ween %he "pec!e" molec le"dec e!ses a,,ec%!n0 %hec$! ge dist i%#tion o,ne!0h#o*!n0 molec le

- %he ef !cti'e inde* o, "ol %!on )?1= -3@+ a*!e"con"! e*a#l .

2. 8n"%* men%al e !a%!on5 a*!"e ,*om ,!n!%e #an pa"" o,!l%e*" o* monoch*oma%o*". @ean" %* lmonoch*oma%!c *a !a%!on) "!n0le wa elen0%h+ !""el om p*ac%!cal


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3. Chem!cal e !a%!on5 a*!"e" when a "pec!e"!""oc!a%e" a""oc!a%e" o* *eac% w!%h a "ol en% %

,o*m a p*o c% ha !n0 !,,e*en% a#"o*p%!on.

e/. !ch*oma%e !on a#"o*#" !n %he !"!#le *e0!on a%4 = nm.

2C*O42- B 2 B ⇔ 2 C*O 4- ⇔ C* 2O72- B 2O

'pon !l %!n0 %he e !l!#*! m "h!,%" %o %he le,%.The

e !l!#*! m can #e con%*olle # con e*%!n0 all %hch*om! m %o C*O42- # ma !n0 %he "ol %!on o,=.= @ !n O


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1. Ra !a%!on "o *ce"5 *o0en o* De %e*! m Famp"

,o* '( *e0!on" T n0"%en !lamen% lamp" ,o* !"an nea*-8R

2. Ga elen0%h "elec%o*5,!l%e*" an monoch*oma%o*"

3. Cell"5 ,o* '( a*% ,o* !"!#le pla"%!c e%c

4. Pho%o e%ec%o*5 pho%om l%!pl!e* % #e"

. Rea o % e !ce

Inst #"ent!tion


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Ty&e of Inst #"ent

!, Single %e!" inst #"ent 5 "!mple"% an lea"%

e/pen"! e one con"!"%" o, a #a%%e* -ope*a%e% n0"%en # l# a" %he "o *ce a "e% o, 0la"" ,!l%e*" ,o*wa elen0%h "elec%!on %e"% % #e" ,o* "ample hol e*"a pho%o ol%!c cell a" %he e%ec%o* an a "mallm!c*oamme%e* a %he *ea o % e !ce


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#+ do#%le %e!" inst #"ent

• 8n o #le-#eam-!n-"pace !n"%* men% %wo #eam"

a*e ,o*me !n "pace # a (-"hape m!**o* c a a #eam "pl!%%e*

• one #eam pa""e" %h*o 0h %he *e,e*ence cell an

o%he* %h*o 0h %he "ample cell "!m l%aneo "l %*e"pec%! e e%ec%o*


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#+ o #le #eam !n"%* men%5

• 8n o #le-#eam-!n-%!me !n"%* men% %wo #eam" a*e

"epa*a%e !n %!me # a ot!ting secto "i o %ha% !*ec% en%!*e #eam ,!*"% %h*o 0h %he *e,e*ecell an %hen "ample cell


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A&&lic!tion 1. #!lit!ti'e !n!lysis

• ha e "ome wha% l!m!%e appl!ca%!on ,o* al!%a%! eanal "!" #eca "e %he n m#e* o, a#"o*p%!on ma/!maan m!n!ma a*e *ela%! el ,ew

• ne e*%hele"" !% !" "e, l ,o* e%ec%!n0 %he p*e"enceo, ce*%a!n , nc%!onal 0*o p" %ha% ac% a" ch*omopho*e • a wea a#"o*p%!on #an !n %he *e0!on o, 2


12/19


13/19

1. Selec%!on o, wa elen0%h5 Ima/ ,*om "pec%* m2. (a*!a#le" %ha% !n,l ence" a#"o*#ance5 "ol en% p

%empe*a% *e !n%e*,e*!n0 " #"%ance".3. Cell han l!n05 len" pape* "oa e !n "pec%*o0*a e

me%hanol ca*e, l *epo"!%!on a c e%%e

4. P*epa*a%!on o, cal!#*a%!on c * e5 ,*om a "e*!e" o,"%an a* "ol %!on" %ha% #*ac e% %he conc. *ane/pec%e ,o* %he n nown "ample

P*oce *al De%a!l"5!n ol e e"%a#l!"hmen% o, wo* !n0con !%!on" an %he p*epa*a%!on o, a cal!#*a%!on c * e


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• %o%al a#"o*#ance o, a

"ol %!on !" e al %o %he " mo, a#"o*#ance" o, %he!n ! ! al componen% p*e"en%A

tot!l = A

) A

23

= ε ) c) l ε 2 c2 l 3

An!lysis of )i*t# es of !%so %ing s#%st!nces

•: mea" *!n0 %he a#"o*#ance a% 2 wa elen0%h )I 1 an I 2+ A1 = ε 1) c1) l ε 12 c12 l 4!t 5 1,

A = ε ) c ) l ε 2 c 2 l 4!t 5 ,


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• 4 mola* a#"o*p%! !%!e"ε1) ε ) ε12 ε 2 can #e o#%a!ne,*om !n ! ! al "%an a* "ol %!on" o, @ an N

• l !" %he cell %h!c ne"" con"%an%• A#"o*#ance o, m!/% *e a% 2 wa elen0%h" )I 1 an I 2+ a*e e/pe*!men%all e%e*m!ne

Th " ,*om %he a#o e %wo e a%!on" conc. o,!n ! ! al "pec!e" c@ an c N can #e calc la%e


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• pho%ome%*!c %!%*a%!on c * e !" a plo% o, a#"o*#anc

". ol me o, %!%*an% an can #e emplo e %omea" *e %hee6#i'!lence &oint o, a %!%*a%!on

• chan0e !n a#"o*#ance o, a "ol %!on !" "e %o ,ollow

%he chan0e !n concen%*a%!on o, a a#"o*#!n0 "pec!e"*!n0 a %!%*a%!on• a#"o*#ance !" !*ec%l p*opo*%!onal %o %he conc. o,

%he a#"o*#!n0 "pec!e"• !n ! eal con !%!on %he plo% con"!"% o, %wo "%*a!0h%

l!ne" %ha% !n%e*"ec% a% %heend &oint

Some o, %he % p!cal %!%*a%!on c * e" a*e5

P$oto"et ic Tit !tion


17/19

a+Ghe*e %!%*an% alone a#"o*#" e/5 %!%*a%o, a*"en!c)888+ w!%h #*oma%e-#*om! ewhe*e a#"o*#ance !" mea" *e a% %he

wa elen0%h whe*e %he #*om!ne a#"o*#" #+Ghe*e %he p*o c% o, %he *eac%!ona#"o*#" e/5 %!%*a%!on o, Coppe*)88+ w!%h

EDTAc+ Ghe*e "pec!e" !" con e*%e !n%o non-a#"o*#!n0 p*o c% e/5 %!%*a%!on o, p-

%ol ! !ne !n # %anol w!%h pe*chlo*!c ac!+ Ghe*e a colo*e "pec!e" !" con e*%e %o

a colo*le"" p*o c% # a colo*e %!%*an% #*om!na%!on o, a *e e"% ,,

!

%

c

d


18/19

Ad'!nt!ges o'e di ect &$oto"et ic dete "in!tion

• p*e"ence o, o%he* a#"o*#!n0 !mp *!%!e" a% %heanal %!cal wa elen0%h oe" no% ca "e !n%e*,e*ence

• acc *ac !" mo*e #eca "e a%a ,*om "e e*al

mea" *emen%" a*e "e %o calc la%e %he en po!n%

• *ela%! el !l %e "ol %!on can #e "e

• nona#"o*#!n0 "pec!e" can al"o #e an%!%a%e


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A&&lic!tion•De%e*m!na%!on o, %he !""oc!a%!on con"%an%" o, weaac! " o* #a"e"•De%e*m!na%!on o, %he compo"!%!on o, comple/ !on" De%e*m!na%!on o, chlo*!ne !n wa%e*

•De%e*m!na%!on o, %he %o%al calc! m an ma0ne"! mha* ne"" o, wa%e* "ample" # pho%ome%*!c %!%*a%!on

•De%e*m!na%!on o, "!l!con calc! m ma0ne"! m !*onan al m!n m !n cemen%" # pho%ome%*!c %!%*a%!on%he "ol #!l! e p*o c%

•Anal "!" o, $am" ,* !% an e0e%a#le $ !ce" an%he!* concen%*a%e"

UV-VIS Spectroscopy.ppt

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