- Thong ke va xir ly so lieu thuc nghiem bang eac phan mem Exell va Matlab.
2.3.2.1. Phuong phap chiet-trac quang nghien ciiu phiic Mo(VI) va W(VI) voi TOAB trong moi truong nuoc axeton
va W(VI) voi TOAB trong moi truong nuoc - axeton
Phd cua phuc Mo(VI) vd H(VI) v&i TOAB
Trong mdi tnrdng nude, ngoai thanh phan cua kim loai \a thuoc thu thi ndng dp axit (pH) cua dung dich la >eu to anh huong co ban den kha nang tao noi phuc cua Mo(Vl) va W(V1) vdi tac nhan TOAB.
Khi dua dung moi huu ca tan \ao dung dich. no sc lam iha> doi tinh ch^t va hanh vi cua dung md. cung nhu anh huouii den kha nang tao phuc cua kim loai vdi thu6c thụ \'i va\ a da\ cac >cu to can nghien cuu la dang
De khao sat pho hap thu quang eua phirc sau khi da dugc ehilt vao toluen, mau nghien cim dugc chuin bj nhu sau: Cho vao pheu ehilt dung tich 50 ml 15,5 ml dem cloaxetat 0,1 M co pH = 3; 1,0 ml dung djch Mo(VI) hoac W(VI) ndng do 5 , 0 . 1 0 ' ' ' M va 7,5 ml axeton, lac dIụ Tilp tue cho them 1,0 ml dung djch TOAB 2,5.10'^ M, lie dIu rli them 5,0 ml toluen, i k manh trong
khoang mot phut. Dc yen 10 phut cho phan Idp hoan toan. tach lly pha hiru
CO, lgc qua gily lgc khd va dem quet phi tir budc song 300 - 700 nm vdi dung djch so sanh la toluen.
Anh hirang cua nong do axeton vd pH đn su tgo phirc
Nghien ciru anh hudng eiia nong dp axeton ciing nhu anh hirong cua pH den kha nang tao noi phirc eua Mo(VI) va W(VI) \di IỌ'\B dugc tien hanh vdi cac mau chuan bj nhu eac mau su dung de khao sat pho hap thụ Dieu khac d day la nong dp kim loai bang nting do cua thuoc thu \a bang
1. lÓ*^ M, axeton tang dan tir 0% den 90° o theo the tich \a pH tha> doi tir 1 - 6 nhu muc 2.3.1.2 va 2.3.1.3. Cac qua trinh chiet va do dp hap thu quang duge tien hanh nhu da trinh bay o phan tren vdi cac dung djch so sanh la mau trang duge chuan bj nhu dung djch phirc nhung khong eo kim loaị
2.3.2.2. Phuong phap chiet-tr5c quang nghien ciiu lien hop ion giua
IVlo(VI) va W(VI) voi CV va BG trong moi truong nude - axeton
Tir nhung nghien ciru \di tac nhan tao noi phirc TỌAB trong moi trudng nude va nucVc - dung moi hiru cọ chiing toi da nhan tha\ su khac biet Idn nhat giua Mo(VI) va W(\'I) dugc tao ra khi moi trirong la nuoc - axeton 30% theo the tich (V/V) va pH 3. Ngu>en nhan cua su khac bict na\ la do trong dilu kien nhu vay Mo(\'l) tin tai chu >cu o dang cation MoOf \a W( VI) tin tai chu ylu o dang anion 11 A\'„():i "'• \ i thẹ nyhicn ciru chict - trac quang Mo(VI) va W(V1) trong eac dieu kicn neu tren \iri cac ba/o mau hiru
ca chinh la nghien cim kha nang tao lien hgp ion giiia cac dang tin tai ciia hai nguyen to nay vdi cac cation bazo mau hiru cọ
Cac yeu t l can khao sat de khang djnh dang tin tai cung nhu kha nang tao lien hgp ion la nong do axeton va pH cua dung djch.
Dung dich de khao sat pho hap thu quang cua lien hgp ion giua kim loai va cac bazo mau huu co dupe chudn bi vdi ndng dp kim loai la 2,0.1 O ' M , nong dp bazo mau huu co la 1,0.10"M, pH bdng 3 va moi trudng la nude - axeton 30% (V/V). Dich chiet cua mau len toluen dupe su dung de quet ph6 hdp thu quang vdi dung dich so sanh la toluen.
Mau nghien cuu anh huong cua nong dp axeton den kha nang tao lien hop ion ciia Mo(Vl) va W(V!) vdi BG hay CV dupe chuan bi \ai nong dp
kim loai la UỌIÓM, nong dp bazo mau huu co la ỊỌIÓM \a p\\ hang 3
duoc dieu chinh va giu on dinh banu dem cloaxetat. Nona do ^'o theo the tich
eiia axeton dugc khao sat tir 0.0 den 90.0°ọ Qua trinh thi nghiem dugc thuc
hien nhu sau: Cho vao pheu chiet dung tich 50 ml 15.5 ml dem cloaxetat 0.1 M cd pH bang 3; 1,0 ml dung dieh kim loai 2.5.10"' M. lac deu trong \6ng 10 giaỵ Tilp theo them 7.5 ml axeton. lac deu va tiep tuc cho them 1.0 ml dung djch thule thu nIng dp 2.5.10'^ M. Sau khi dung dich dupe tron deụ cho them
5,0 ml toluen va \hc manh trong vong mot phiit. De \en 10 phut cho phan Icrp hoan toan; tach lly phIn dich ehilt. Ipc qua gia\ Ipc kho \a dem do do hap thu quang. Dii vdi thule thu BG do o budc song 630 nm \a doi \oi C\' thi
do a budc song 599 nm. so sanh \oi mau trang o cung dieu kicn.
De n^hien ciru anh huong cua pi I dung djch. mau cimg duoc chuan hi
gilnu nhu tren. nhirng gia tri pi I cua da\ dung djch (\uoc on diiih hang cac he
va NaOH 0,1 M sao cho cd cac gia trj la 1,0; 2,0; 3,0; 4,0; 5,0 va 6,0. Cac qua trinh chiet va do dp hap thu quang duge thuc hien nhu tren.
r t
2.3.2.3. Danh gia phu-ong phap va xay dung du-tmg chuin xac djnh MoOz^^ b^ng TOAB va H3W602,^ b^ng baza mau huu ca MoOz^^ b^ng TOAB va H3W602,^ b^ng baza mau huu ca
Du&ng chuan xdc dinh
Trude khi khao sat vung nong dp kim loai tudn theo dinh luat Beer, cac yeu to anh hudng den dp hap thu quang, dp ben mau cua phuc va do nhay cua phan ung mau nhu thdi gian ben mau, s6 Idn chidt. thanh phan phuc tao thanh va lupng thuoc thu du ciing dupe khao sat. Cac mau nghien cuu co n6ng do kim loai 1,0.10"^ M, dugc thuc hien nhu mo ta trong muc 2.3.2.1. va 2.3.2.2. vdi mdi trudng nude - axeton 30% (V/V) va pH 3 dupe dieu chmh bang dem cloaxetat. Lugng thuoc thu du dugc chuan bi nhu trong bang 2.3
Bdng 2.3. Ndng do thudc thu dw trong dung dich nghien ciru
CioAB.lÓ- M C,K,.10-- M Ccv-lÓ-'M 1,0 0,5 0,5 1,5 ỊO 1.0 2,0 1.5 1.5 2.5 2.0 2.0 3.0 3.0 3.0 4.0 4.0 4.0 5.0 - - 6.0 -
Dii vdi vice xay dung dudng chuan. chiing toi khao sat moi urong quan giua do hip thu quang cua phirc \di nong dp kim loai trong dung dich de bilt duge khoang tuyin tinh cua kim loai tuan theo dinh luat Beer. \ i e c chuan bj mau va do quang dich chiet dugc tien hanh nhir tren. nhung nong do thuoc thu BG la 3,0.10'' M; TỌ'XB la 2.0.10'' M \a C\' co nIng do la 1.5.10"^ M
Bdng 2.4. Anh hu&ng ciia ndng do kim logi den do hdp thu quang C M O O 2 ' ' . 1 0 - ' M T ^ CH3W602I . 1 0 ' M 0,1 0,1 0,2 0,2 0,4 0,3 0,6 0,4 0,8 0,5 1,0 0,6 1,2 0,7 1,4 0,8 1.6 0,9
Sau do tir phuong trinh dudng ehuin thu dugc kilm tra sai s i he thing cua phuong phap va tim gidi ban phat hien (LOD) cung nhu gidi ban djnh lugng (LOQ).