Đặc điểm thủy lực và xâm nhập mặn cửa sông đáy

Dai hpc Quoc gia Ha noi Trircmg Dai hoc Khoa hoc Tir nhien ^ f ^if ^if ^1^ ^J{f ^ f ^if ^if ^if NGHIEN ClTU CHE TAO DIEN ClTC THAN MEM • • • BIEN TINH OXIT THUY NGAN VA ITNG DUNG TRONG PHAN TICH VON-AMPE HOA TAN Ma so: QT 09-28 Chii tri de tai: Th.S Le Thj Huang Giang Ha noi - 2009 Dai hoc Quoc gia Ha noi Trucmg Dai hoc Khoa hoc Tir nhien * hf« a i # « t ^ %lr ^IM m±m %S* %iM fj* *J» ^J^ ^ * *J» ^fm *|^ wfi Ten de tai: NGHIEN CUU CHE TAO DIEN ClTC THAN MEM BI EN TINH OXIT THUY NGAN VA UNG DUNG TRONG PHAN TICH VON-AMPE HOA TAN Ma so: QT 09-28 Chij tri de tai: Th.S Le Thi Huoug Giang Can bp tham gia: CN Nguyen Tho Khiem QAl HOC WUUC GiM HA N p i '^\JN0 ^AM THCNG i"iM THU ViEN Ha noi - 2009 Bao cao torn tat Ten de tai: "Nghien curu che tao dien circ than mem bien tinh oxit thuy ngan va urng dung phan tich von-ampe hoa tan" Chu tri de tai: Th.S Le Thi Huorng Giang Cac can bo tham gia: CN Nguyen Tho Khiem Muc tieu va noi dung nghien ciiii, - Nghien cixu che tao dien circ than men bien tinh oxit thiiy ngan - Khao sat cac dac trting dien hoa ciia dien cue - Xay dung quy trinh phan tich Cd(II) bIng phuong phap von-ampe hoa tan hap phia sij' dimg dien circ than mem bien tinh oxit thuy ngan va ling dung phan tich mSu thirc te Cac ket qua dat duac 5.1 Da che tao dien circ than m6n bien tinh oxit thiiy ngan va khao sat cac dac trung dien hoa ciia dien cue 5.2 Da xay dii'ng quy trinh xac dinh Cd(II) bang phuang phap von-ampe hoa tan hap phu su dung dien cue than mem bien tinh oxit thiiy ngan 5.3 Ung dung phan tich ham luang Cd(II) mot so mSu thue te Danh miic cac bai bao 1, Tran Chuang Huyen, Le Thi Huang Giang, Nguyen Minh Quy, Nghien cuu ma rong pham vi ung dung ciia dien cue paste caebon bien tinh, Tap chi Hoa hoc, T47 (5A), p 268-272, 2009, Tran Chuo'ng Huyen, Le Thi Huang Giang, Nguyen Minh Quy, Xac dinh Cadmi bang phuang phap von-ampe hoa tan hap phu catot tren dien cue paste caebon bien tinh bang HgO, Tap chi Hoa hoc, T47 (5A), p 280-284 , 2009 Tinh hinh kinh phi cua de tai Kinh phi duac cap: 25.000.000d (Hai mucfi ldm trieu dong) Thue khoan chuyen mon: lO.OOO.OOOd (Mudi trieu dong) Chi phi vat tu: 13.000.000d (Mudi ba trieu dong) Thanh toan dich vu cong cong: 2.000.OOOd (Hai trieu dong) Khoa quan ly Chu tri de tai ^yjUfid^'^ Th.S Le Thi Huong Giang Co quan chu tn de tai GS.TSKH.^CW«^!^^^^^'^^^^ L Title PASTE CACBON MODIFIED BY HgO ELECTRODES AND THEIR APPLICATION IN STRIPPING VOLTAMMETRY Code: QT 09.28 Managing Institution: Ms Le Thi Huong Giang Implementing Institution: Nguyen Tho Khiem Collaborating Institutions: Coordinator: Key implementers: Duration: (from April 2009 to April 2010) Budget 25.000.000 VND 10 Main results: In general, mercury electrodes such as the hanging mercury drop electrode (HMDE) or thin-film mercury electrode (TFME) have been used for anodic stripping analysis because of their distinctive analytical characteristics However, the use of the hanging mercury drop electrode has been hesitated due to the difficulties in handling liquid mercury and disposing of used mercury In this work, we studied on the preparation and characterization of paste caebon modified by HgO electrodes, foreusing in particular on their stable and reliable stripping electroanalytical performance The useful negative potential windows of the HgO electrodes in the pH range 1.0 - 5.0 (+0.2 to 1.4V) The electrode surface can be renewed easily either by a simple polishing process for the bulk-modified electrode or by simple exchange for the disposable type sensing probe Finally, the method was applied to the determination of lead in some samples with satisfactory results This modified electrode was to determination of Cadmium by adsorptive calhodic stripping voltammetrie in the presence of xylenol orange Highly sensitix'c procedures are presented for the determination of eadimium by adsorptive cathodic stripping voltammetry with ligand competition using xylenol orange (XO) The most suitable operating conditions and parameters such as buffer, pH, deposition potential, deposition time, ligand concentration, scan rate and others were selected and the determination of cadmium from aqueous solutions using the standard additions method was possible The optimum conditions was investigated Optimal analytical conditions were found to be an xylenol orange concentration of 6.10"^ M, a pH of and accumulation potential at - 1.2 V vs Ag/AgCl reference electrode, the potential is scanned in a negative direction from - 0.4 V to 0,9V With the optimized condition, the 3a limits of detection for Cd (II) are 2.I0"'^M The method is successfully applied to determination of cadmium(II) in water sample Tranj Ma dau n Noi dung H.l Gioi thieu ve Cd II 1.1 Tac dung sinh hoa ciia Cd II 1.2 Cac nguon dua cadmi vao moi truong tu nhien va ca the ngudi II 1.3 Cac ung dung cua Cd II 1.4 Tom tat cac cong trinh nghien cuu xac dinh Cd bang phuong phap dien hoa hoa tan II.2.Lua chon doi tugng nghien cuu 11.3 Noi dung nghien cuu II.3.1 Nguyen tac chung cua phuong phap von-ampe hoa tan IV.3.2 Nguyen ly phep 11,3.3 Gioi thieu \e phuong phap von-ampe hoa tan hap phu I1.3.4.Cji6i thieu ve dien cue than men bien tinh bang HgO II.3.5 Xiic dinh Cadmi Iheo phuong phap von-ampe hap thu voi thuoc thu Xylenol da cam tren dien cue paste caebon bien tinh bang HgO 11.3.5.1 llu diem ciia Xylenol da cam (C3iH280i3N2SNa4) so voi chat tao plu'rc khac 11.3.5.2 Co che hap phu cua Cd voi thuoc thu qua trinh tien hanh phan tich 11.4 THUC NGHIEM 11.4.1 HOA CHAT-DIJNG Cy 11.4.2 CHE TAO DIEN CLJ'C 10 n.4.2.1 Khoang the hoat dong va khoang pH toi uu cua dien cue i 10 II.4.2.2.Kiem tra dp ben cua dien cue dung dich lam viec: 11 II.4.3.Cac dieu kien \ac dinh Cd (11) 12 11.4.3.1- Khao sat pH va cac nen thich hop 12 11.4.3.2 Khao sat nong thuoc thu xylenol da cam 13 11.4.3.3 Khao sat the dien phan 14 11.4.3.4 Khao sat thai gian dien phan 15 II.4.3.5.Khao sat the hap phu 17 II.4.3.6.Khao sal thai gian hap phu 18 II.4.3.7.Khao sat toe phan cue 18 11.4.3.8 Khao sat bien dp xung 19 11.4.3.9 Khao sat tAn s5 21 11.4.4 Khao sat anh huang cua cac ion khac 21 11.4.5 Duong chuan, dp lap lai va giai han phat hien: 22 II.4.5.1 Dp lap lai va gioi han phat hien 22 II.4.5.2.Xay dung duang chuan 23 11.4.6 Mot so ket qua xac dinh Cd(II) mau 23 IV KET LUAN: 26 Tai lieu tham khao 28 L Mo dau Phuang phap Von ampe hoa tan la mot nhijng phuang phap phan tich lupmg vet cac kim loai nang voi giai han phan tich thap va dp chinh xac cao Cac phuang phap thucmg su diing dien cue lam viec la dien cue gipt Hg tree (HMDE) hoac dien cue mang Hg tren cue ran dia quay (MFE) [1], dien cue glassy carbon [3], [4], [5] hoac dien cue mang bismut [2] Trong cong trinh nay, chiing toi nghien cuu che tao dien cue paste caebon bien tinh bai HgO Bang each trpn them HgO voi paste caebon theo mot ty le nhat dinh, dien cue co the phan tich cac kim loai den nong dp ppb Ngoai cac uu diem cua dien cue la co the su dung de phan tich ham lugng cac kim loai vai gioi han phat hien thap, dp lap va dp chpn Igc cao ben va it dpc hai cho moi truang, pham vi ung dung cua dien cue cac dung dich co pH khac cijng da dugc nghien cuu Bang each hoat hoa be mat dien cue dung dich HCl 10" M mot thai gian nhat dinh truac phan tich, ket qua cho thay co the su dung dien cue paste caebon bien tinh bai HgO de phan tich cac chat cac dung dich dem khoang pH tu den 10 Cd la nguyen to kim loai nang co kha nang tich lijy va co dpc tinh cao doi vai moi truang Cadmi la nguyen to thupc nhom kim loai chuyen tiep tu nhien no ton lai nhieu dang, mac du ham lugng tu nhien it nhung Iai co dpc tinh gap 1000 lan Pb Ham lugng cho phep cua Cd nuac la 3ppb, cua Pb lOppb Cadmi xam nhap vao ca the nguai thong qua duang an uong cac dpng vat thuy sinh bi nhiem Cadmi hoac hit phai khong co chua bui Cadmi Den mot giai han nao se co nguy ca gay tu vong Vi vay viec xac dinli ham Cadmi dugc tich luy lugng cadmi co cac doi tugng moi truang rat quan trpng Co nhieu phucmg phap xac dinh Cd cac mau nhu phuang phap hap thu nguyen tu phuang phap so mau, phuang phap dien hoa hoa tan [6], [7],[8] Phuang phap von ampe hoa tan hap phu la mot nhung phuang phap CO dp nhay cao dung xac djnh Cd [7],[8] Trong cong trinh nay, chung toi su dung dien cue paste caebon bien tinh bai HgO xac djnh lugng vet Cd(II) bang phuang phap von-ampe hoa tan hap phu vai tlnioc thu xylenol da cam (XO) co the dat dugc lap tot voi dp lech chuan tuang doi 1.01% va va giai han phat hien 2.10'''M II Noi dung ILL Giffi thieu veCd II.LL Tac dung sinh hoa ciia Cd Cadmi la nguyen to rat dpc giai han toi da cho phep ciia cadmi: Trong nuac : 0,003 mg/1 (hay 3ppb), Trong khong : 0,001 mg/m\ Trong thuc ph4m : 0.001- 0,5 fig/g •Trong tu nhien cadmi thuang dugc tim thay cac khoang vat co chira kem nhiem dpc cadmi gay nen chung benh gion xuang O nong dp cao, cadmi gay dau than, thieu mau va pha huy xuong •Ph4n lan cadmi tham nhap vao co the nguai dugc giu Iai a than va dugc dao thai, mot ph^n it (khoang 1%) dugc giu lai than, cadmi Hen ket vai protein tao metallotionein co a than Phan lai dugc giir lai ca the va dan dan dugc tich luy cung vai tuoi lac Khi lugng cadmi dugc tich tru lan, no co the the cho ion zn"^ cac enzim quan trgng va gay roi loan tieu hoa va cac chiirig benh roi loan chuc nang than, thieu mau tang huyet ap, pha huy song, gay ung thu ILL2 Cac nguon dua cadmi vao moi trutfng tu* nhien va co* the nguoi Cadmi xam nhap vao klii quyen nuac qua nguon tu nhien va nhan tao bui niii lua bui dai duang liia rung va cac da bi phong hoa la nguon goc tu nhien chinh, dac biet la niii lua gay nhiem cadmi Trong nguon nhan tao thi cong nghiep luyen kmi, Ipc dau gay nhiem cadmi nhieu nhat Cadmi xam nhap vao ca the nguai, chii yeu qua thuc an tu thuc vat dugc tren dat giau cadmi hoac tuai bang nuoc co chua nhieu cadmi II.1.3 Cac ung dung cua Cd • Ma dien (chiem 7%): cadmi dugc ma len be mat chat dien phan hoac may moc de tao be mat sang bong va chong an mon Cac san pham chinh bao gom: + Ndng thudc thu tao phucC thu6cui^= 6.10''M + Tdc dp quet th§= 250 mV/s + Bien xung 50 mV + T4n s650 Hz +Tbdi gian dien phan tjp = 90 s + Thd h^p phu Ehp= -0,4V + Thdi gian sue t = 300s Da khao sat anh huang cua mot so ion kim loai: + Fe" , Cu ^,Zn "" hau nhu khdng anh hudng +Pb cd anh hudng den chieu cao pic Cd^^ nhung van cd the xac dinh dugc Cd bang phuang phap them cbu4n cd mat cua Pb^"" Da xac dinh ham lugng Cd^^ mdt sd mau nudc bang phuang phap them chuan: + Mau nuac Hd Tay ( khu vuc chua Tran Qudc) :l,2ppb + Mau nude hd Bay mau: : 4,02± 1,34 ppb + Mau nudc hd Tay (khu vuc phu Tay Ho) 2,74±0.55ppb + Mau nudc sdng Nhue: 2,53 ±0,26 ppb + Mau nudc may khu Dinh Cdng: 2,73±0,23 ppb Kien nghi Tiep tuc hudng phat trien cua de tai, nghien cuu phuang phap von-ampe hda tan b4p phu su dung dien cue than mem bien tinh oxit thiiy ngan xac dinh ddng thdi cac kim loai, cac vitamin, cac chat khang sinh 27 Tai lieu tham k h a o chinh [1] Tran Thi Thu Nguyet, Tr4n Thu Quynh, Tu Vong Nghi, Nghien cihi xdc dinh mot sd kim loai ndng nuac bdng phuang phdp Von-ampe hda tan dung hinh dien hda dong chdy Tap chi phan tich hda ly va sinh hpc, Tap 4, sd 3, 1999 [2] Nguyen Van Hgp, Trin Cdng Dung, Nguyen Hai Phong, Tu Vpng Nghi Hoang Tho Tin, Phdt trien dien cicc mdng bismut di xdc dinh Cu^' Pb" Ccf'vd Zn" bdng phuang phdp von-ampe hda tan anot Tap chi phan tich hda ly va sinh hpc, Tap 9, sd 3, 2004 [3] J.F van Staden, M.C Matoetoe Simultaneous determination of copper, lead, cadmium and zinc using differential pulse anodic stripping voltammetry^ in a flow system Analytica Chimica Acta 411 (2000) 201-207 [4] Chengguo Hu, Kangbing Wu, Xuan Dai, Shengshui Hu Simultaneous lead(II) and cadmium(II) at a diacetyldioxime modified dctennination carbon paste electrode of by differential pulse stripping voltammetry Talanta 60 (2003) 17- 24 [5] Kangbing Wu, Shengshui Hu, Junjie Fei, Wen Bai Mercuiyfree determination simultaneous of cadmium and lead at a glassy carbon electrode modified with nndti-wall carbon nanotuhes Analytica Chimica Acta 489 (2003) 215-221 [6] Nguyen Van Hpp, Tran Cdng Dung, Nguyen Hai Phong, Tu Vpng Nghi, Hoang Thp Tin, Phdt trien dien cue mdng bismut de xdc dinh Cu" Pb", Cd"vd Zn" hdng phuang phdp von-ampe hoa tan anot Tap chf phan tich hda ly va sinh hpc Tap 9, sd 3, 2004 [7] Pompilia Suciu, Marisol Vega, Liviu Roman Determination of cadmium by dijfcrential pulse adsorptive stripping voltannnetr ]ouma\ of Pharmaceutical and Biomedical Analysis 23 (2000)99-106 [8] Jose A Jmado-GonzedQZ Experimejitai designs in the development for tJie sensitive determination of cadmium in seawater by adsorptive of a new method cathodic stripping voltamnietiy KnaXyXica Chimica Acta 487 (2003) 229-241 28 PHU LUC B^I HOC QUOC GIA S A NOI B A I H O C BCHOA H O C TU' NHIE-N ICHOA H O A H O C 5^', ^ [P ii^e V lec Ann NGHIEN CUtJ XJ.C BINK Cd BANG PSU^ONG PHAP VON-AMPE HOA TAN CATOT SCT B^UNG BIEN ClTC THAN MEM BIEN TINH OXIT THUY NGAN KHOA LUAN TOT NGHIEP HE BAI HOC CHINH QUY Nsanh Hoa ohan ti Gido vien kw&n2 din: ThS« Le Thi Hircmg Giang Ha noi - 2009 Tap chi phan tich Hda, Ly vd Sinh hoc • Tap 14, So 412009 D I E N CLfC PASTE C A C B O N BI^N T I N H BANG HgO VA LPNG DUNG T R O N G PHAN TICH V O N - A M P E HOA TAN A N O T Phan 2: Xac dinh dong thai mot s6 kim loai nang tren dien cue paste caebon bien tinh b^ng HgO Den toa soan 14-5-2009 Tran Chiro'ng Huyen, Le Thj Hirang Giang Khoa Hoa Dgi hoc KHTN Dgi hoc Qudc gia Hd Ndi Nguyen Minh Quy Khoa Cong nghe Ky ihugt Phdn tich Tru&ng Cao dang Hoa chut Phi'i Vic SUMMARY PASTE CACBON MODIFIED BY HgO ELECTRODES AND THEIR APPLICATION IN STRIPPING VOLTAMMETRY Part Silmutaneous determination of some heavy metals using paste caebon modified by HgO electrodes This pape report the simuhaneous determination of some heavy metals using paste Luchc modified by HgO electrodes for anodic stripping voltammetry The optimum conditions wc investigated The linear domain range ofCufll), Pb(II) Cdfll), Znfll) are W^ den W M, 5.10"' dt 5.10'^ M, 5.I0''^MdSn 5.10'^ M, 4.10'^den 4.}0'\M respectively With the optimized condition, (he limits of detection for Cu(II) - 8.I0''M, Pb(II) - 4.4 W'M: M,9 ppb) ; Zn (IT) - S.W M ( = O.t ppb): Cd(II) - 2.8 lO'^M f^ OJJ ppb) at the deposition times of 90s : the relative standard deviation ( 10 ppb is 0,34 %for Cu(II), Pb(II) - 5.8%: Cd(II) - 2,1%: Zn(II) - 1.73% at 20 ppb finally pas caebon modified by HgO electrodes were successfully applied to the determination of Sivne hea\ metals in natural waters, domestic natural water with satisfactory results I M D A U n THUC NGHIEM ,,, , , - ^ ~ ^i ^ iu' • 2.LThietbiva hoa chat Trong [1], chung toi da de cap tai kha nang su , , , \ u-^ *.' u \.~ -u r\ He thiet bi phan tfch cue phd AUTOLA dung dien cue paste caebon bien nnh bang HgO • x \ ^- • -• i. WA r J ^ U /7 A III (Ha Lan) di kem vai he VA Stand di de phan tich bang phuang phap von ampe hoa tan (^i.^^^^^jhuy Si) He gdm dien cue: Du anot Trong bai bao nay, chung tdi trinh bay nhung ^^^ y^^ yj^^: Dien cue HgO/C (ti le 1:2) Dit k^t qua ap dung de phan tich ddng thdi lupng vet cac cue so sanh: Ag/AgCI/KCI bao hoa; Dien ci ion mot so ngudn nirdc phu trp glassy caebon 14 Dung dich Cu(II), Pb(II), Cd(II), Zn(II) dugc pha tir dung dich chuan cua Merck Nirdc sach de pha che cac thudc thu va trang rua dung cu la nudc cat lan Cac dung dich lam viec dupe pha hang tu cac dung dich chuan gdc ' 2.2.Cac dieu Iden Di^n cue lam viec dupe mai nhin va hoat hoa bk mat trirdc sir dung Di§u kien do: Edp = -1,3 V; thdi gian dien phan 90 s; toe dp phan cue 250mV/s; theo che dp sdng vuong tdn sd 50Hz; bien dp 50mV, nong dp nen Cl" 0,1 M, pH = 2,5 : if* ica^ I , KK^ ^A Khao sat ndng dp dung dich nen Cl tu 0.01 den 0,2 M cho thdy vdi ndng dp tir 0.05 den 0.1 M, dudng nen thap va phang, chiing tdi chpn ndng dp nen 0,1 M cho phep xac dinh Trong mot sd tai lieu xac dinh cac kim loai theo phucmg phap von-ampe hda tan [3], [4], pH d6 xac dinh Cu(II), Pb(II) Cd(II) co th^ thay ddi tir den 5, pH xac dinh Zn"' co the lu den Idn han [5], [6] Chiing tdi lien hanh khao sal khoang pH tir Iden va thay rang; Vdi pH tir den 2, pic ciia Pb(II), Cu(II) va Cd(II) tirang ddi Idn , nhung pic ciia Zn(ll) thi thdp chan pic Cu(ll) khdng phang Vai pH tu den 4, cac pic ciia ca kim loai cd chieu cao kha deu nhung hoi thap, cac pic tach khdng duac tdt Gia tri pH thich hpp nhdl la 2.5 vd dupL -liing cac khao sat tiep sau A Mu lP;ccu:tZn-', Cd^' ?b=*, Cu-* 5ppb I PIC cuaZo** CJPb**, Cu^* 10 ppb 3.1.3 Khao sat anh hu-oTig cua pH, nong nen va anh hu'ong qua lai giira cac ion: \ ^ V 'J 1 :&-i t a o 10-0 *a-j jj-o : o o CO Hin/i J Sir xudt hien pic cua Cu(II), Pb(IT) Cd (II) Zn(II) Tien hanh thuc nghiem theo dieu kien nhu muc 2.2 Ket qua la pic ciia Pb(II) xuat hien d the -0,43 V, pre ciia Cd(n) xudt hien d the -0,64 V, Cu(n) d - 0.09 V cdn pic ciia Zn(n) xudt hien d - 0,97 V (so vdi dien cue Ag/AgCl) 3.L2 Khao sat the dien phan lam giau(Edp) Khao sat vdi cac the dien phdn tir -1,1V den -1,5V, cho thay Edp thich hap nhdt la -1,3 V.6 cac th§ dien phan duang han, pic ciia Zn(II) khong xudt hien hoac rdt thap the dien phdn am hon -1,3 V, cd qua trinh khir hidro lam cho phep lap lai kem, pic hda tan cua cac kim loai tren bj che hoac nhieu Gid tri Edp duac chpn cho cac khao sat tiep sau io - '.'co -o.«o -o'«o - c o -o—o o.£o Hinh 2, Duong hda tan ph\i thudc pH (LpH>3: 2.pHtu2-3: 3.pH [6] J.F van Staden M.C Maioetoe Simultaneous determinaiion oJ copper, lead cadmium and ztnc using differential voltammetry puLe anodic stripping in a V KET LUAN svstem Analytica Chimica Acta 411 - Sir dung phuang phap von ampe hda tan xdc 20^,(2000) flow dinh ddng thdi Cu(II), Pb(II), Cd(II) , Zn(II) tren ["1 Chengguo Hu Kangbing Wu Xuan Dai dien cue paste caebon bi^n tinh dat duoc gidi Shengshui Hu Simultaneous determination of han phat hien thdp, dp nhay va dp chpn Ipc cao, leaddl) qua trinh phan tich nhanh va tien lgi, gidm thieu diacetyldioxime and cadmium(II) dpc hai cho mdi trudng Vi vdy, cd the de dang electrode ap dung dh xac dinh cac kim loai tren cac voltammetry TalantSL 60, 17- 24, (2003) modified by differential carbon pulse Cong trinh dugc hoan tir nguon kinh phi h6 trg 6k tai QT 09-28 Ei^; at at a paste stripping 17 Tap chi Hoa hoc, T 47 (5A), Tr 280 - 284, 2009 XAC DINH Cd B A N G PHUaNG PHAP VON AMPE HOA TAN H A P PHU CATOT TREN DIEN CUC PASTE CACBON BIEN T I N H BANG HgO D,^n Tda soan 20-8-2009 TRAN CHU'ONG HUYEN' LE THI HUONG GIANG' NGUYEN MINH QUY" 'Khoa Hda hoc, Trudng Dgi lioc KHTN Dgi hoc Qudc gia Hd Ndi - Khoa Cdng nghe Ky thug! Phdn tich Trudng Cao ddng Hda chdt Phu Tho ABSTRACT There manv methods for determination oi cadmium Each has advantage and disadvantage hi (his paper we investigation and use adsorptive cathodic stripping voltammetrie method using Paste carbon Modified Electrode for delermination of cadmium to instead of hanging mercury drop electrode (HMDE) in the presence of xvlcnol orange Highly sensitive procedures are presented for the deierminalion of cadmuum bv adsorptive cathodic stripping voltammetry Miih ligand competition using xvlcnol orange (XO) The most suitable operating conditions and parameters such as buffer pH deposition potential, deposition time ligand concentration, sc rate and others were selected and the determination of cadmium from aqueous solutions using the standard additions method was possible The opmuum conditionswasinvestig^^^^^^ analytical conditions were found to be an xvlcnol orange concentraiion of 10 M a pH of and accumulation potential at -1.2 I vs Ag'AgCl reference electrode, the potential is scanned m a negative direction fi-om-0 V to-0.9 V With the optimized condition, the a limits of detection forCd (II) are JO'' M The method is siiccessfullv applied to determination of cadmiumdl) m water sample - MO DAU Cd Id nguyen td kim loai nang co kha nang tich liiv va cd ddc tinh cao doi voi mdi trudng Co nhi^u phuang phap xac dinh Cd cac mau nhu phuang phap phd hap thu nguyen tu phuo'ng phap so mau phuang phap dien hda hoa tan [2 51 ,Phuong phap von ampe hda tan hap phu la mpl nhung phuang phap co dp nha> cao dimg \ac dinh Cd [4 5] \ lec su dung phuong phap \on ampe hda lan hap phu vni flipn r\rr o\ni M deu ^^^^^^^ j^^j ^,^1^ i^^jet phan tich (cua Merck hoac ^^^^.^.^^^ duong) \a nuoc cat hai lan ^^^^^^ ^.^^^ ^^^ ^^.^ ^j^^^^ ^1^^ xxlcnol da ^^^^^ ,M^frckJ ^ ,^ Dung d|ch Cddl) chuan goc 1000 ppm cua Merck y;^^.^^ ^^^^ tiph j^hi^t 99,99% ^ ^^^^^^ ^^^^^ ^^.^ ^^^ mai bdng, hoat hda be mat bang each phan eye tuan hoan chu trinh tir +1 V den -1 V; dung dich nen dem phdt phat 10"^ M; pH = 6; ndng dp thudc thir xylenol da cam 6.10"^ M; dien phan lam gidu -1,2 V; thdi gian dien phan 90 s, sau dd chuyen ve -0,4 V giir s, phan cue catot theo che dp sdng vudng vdi tdc dp quet the 250 mV/s pic xudt hien d khoang the -0.6V (so vdi cucAg/AgCi) liet bi phan tfch cue phd AUTOLAB ^a Lan) di kem vdi he VA Stand 663 i,Thuy ST) He gdm dien cue: cue lam viec: Dien circ HgO bien tinh th6i lirgng HgO:C la 1:2, be mat dien mai bong hang ngdy trudc tien nghiem ;irc so sanh Ag/AgCI/KC! bao hod lire phu trg glassy caebon Ill ~ KET QUA VA T H A O LUAN iingcu thiiy tinh nhu cdc, buret, pipet, phan deu dugc lam sach ky va ig dung dich HNO3 10% trudc Khao sat anh hirong ciia pH va cac nen thich hop Tien hanh thf nghiem vdi cdc dung dich cd pH thay ddi dieu kien nhu tren ket qua trinh bay bang I u kien \ac dinh Cd (H) circ paste caebon bien tinh [1] dugc Bang J Anh hudng cua pL den chieu cao pic Cd(II) 4.5 5.5 0.33 0.59 0.66 0.96 Polvnomiat Fit ol Oata1_B 1.02 1.04 1.02 0.58 0.21 ban chieu rdng hep, vi vdy chimg tdi chpn pH = gia tri dugc chpn cho nhiing kliao sat tiep sau Khi su dung dung dich dem van nang pic thu dupe cdn ddi va cd chan phang cdn diing dem phot phat chan pic hai lech, nhung pic cao hon dem dugc chgn cho cac khao sat tiep sau Tiep tuc khao sat ndng dp nen thay ddi tir 2.5.10"' M den 5.10'' M chiing tdi chpn ndng dp nen 10" M va giCr gia tri cho cdc khao sat tiep sau thi bieu dien su phu thuoc ip Cd(in vao pH gia tri pH tir 4.5 den pic hap phu in doi d pH = pic dat gia tri cao Khao sat the dien phan Tien hanh khao sat anh huong cua the dien phan lam giau tdi gia tri Ip Dieu kien khao sat nlur muc 2.2 Ket qua trinh ba\- bang Bang Anh hudng ciia the dien phan 512 •0.6 -0.7 0.563 0.65 -0.8 -0.9 0.783 cho thdy the dien phdn -0.5 V, I pic qua trinh hdp phu phirc Cd- 0.84 1.1 I 0.90' -1.4 0.94- 0.9 0.792 XO len be mat dien cue.Khi the dien phan tang \k chieu am chieu cao pic cang tang tu> nhien phu se khukh tdn vao dung dich lam giam khdn! '^-'^" ^''''" ^"' ''^" -^'' ^- '^'^'^'^ ^^^ P'" ng tang, pic khdng can ddi cd nhi^u tap chdt chi^u cao pic De han che cac anh huong tren cung bi^khir vi K-ay chiim: tdi chon the dien chiinu tdi chpn thdi gian hdp phu la s cho cdc Plan - ! - V pic cao va cdn ddi ThC- dien phdn khao sdt tiep theo -laydLrgc chon cho cac khao sat uep sau.' Khao sat anh hirons ciia tdc phan circ Khao sat anh hirOnii cua thcVi "ian dien bien \uno, tan sd phan " Dc CO cac dieu kien ghi Jo thich iiop cho Dieu kien nhu muc 2.2 Khao sat anh cac mihien cuu tiep theo chung tdi da k:-,a.^ sat hLTonu cua tho gian dicn phan tai I, Ket qua anil huong cac dieu kien ghi den ctucu cao cno thay: Tang thai j^ian diC-n phan cuon-j dd \a hinh dang pic !iap phu cua phuc Cd (11) va tlong se tang V,c lua ciion thai ^.lan dien phan iim duoc dieu kien roi u'u (duong nen -ihang thuoc vao ndng Cd(ll) iron- duni: chan pic can va Ip du lo'n) nhu sau Phan cue d|ch.Tu> ihugc vao nonu dd CdMii tronu mdu" theo k> thuat song \u6ng AE = -50 mV L.,,.,,= CO the chpn thai gian di,n phan ihich nap Khi m\' tan so 50 Hz toe phan cu'c 250 mV.s nong ilo Cdfll} khoanu n.lO'^ M thi thoi Tronu ^fua irinh kiiao sat cac dieu kien kivic gian dien phdn 2-3 phut Tr.Mvg nghion cuu nax duoi ci^ Jmh nhu tren chung tdl chon thai gian dicn phdn ^Os Thoi " Khao sat anii lurmm cua nonsj thudc gian na> duoc su dung trom: nhfin- kha^^ at ihu- xylenol da cam tiep sau Chon non'2 thudc thu thich !io'p rat quan neu nong tluioc tlur oua thdp su tao Tien hanh khao sat voi cac the hap phu V phuc \o\ CJ (II) khong hoan toan neu ndng -O.IV; -0.:V: -0.3 V; -O.aw -().: \;': -0.55 \ \ thuoc thu qua Ion r^c \av ^u' liap phu canh chiing toi nhan ihav: cac the du\y\^•.l hon -i).4 tranii giua thuoc thu \a phirc Cd-.\() lam giam V cac pic hap phu co cluin hi lech, khong can Jijn lich be mat diC'ii cue dan den giam Jo nha> doi o' cac the am hon -0.4 \' pic ilui duoc can \vi Jo lap cua phep Jo doi iion nhung chieu cao pic giam Voi ihc h:ip I'lcn hanh khao sat \oi cac IIOIIL: JO thuoc phu -0,4 V pic cao va can dn \\ \a\ cluim: loi thu tang dan lu' 10 M Jen Z.W)' \ cac Jicu chpn the hap phu -0.4 \' cho cac khao sat tiep kien vlo khac khung Joi ket qua clni thay nong sau ihnoc llur 0.1 0'" M la thich iiop nlial Khiio sat anh huoni: cua the hap phu Khao sat anh huonii cua Ihoi liiaii hd[) pini S Khao sal anh hunnii cua cac ion khac Thdi gian iiap phu la mdt thong so rat uuan trpng dnh huong toi nliav cua phuang pliap Chiing tdi tien hanh khao sat the hap phu tha> ddi tir den 15 s cac dieu kien nlur tren Ket qua cho thay: Thdi gian hap phu cang ngan chieu cao pic cang lo'n Tu\ nhien neu tlioi gian hap phu qua ngan qua trinh tao phuc \'a hap phu len be mat dien cue chua ddng deu \a on dinh nen chan pic lech han, pic doang rong \ e u thdi gian hdp phu qua dai lugng Cd(ll) \ua hap Tien !i;inh kiiao sat anh huong cua cac kiin loai nang co the khu gan \o'! Cd (11) va thuong CO mat cac mdu phan ticii CJ (II) Ghi Juong hap phu cac Jung Jich CJlll) co nong dp 10" M co them lan luot vao moi Jung dich cac ion Znill) Cu(ll) Pbdh Fedlh vai nong Jo tang Jan dieu kien Jo nhu muc 2.2 Kel qua cho thav a bang bieu Jien chieu cao pic CJ(ll) kiiong co \a co cac ion anh huomi vai tv le Me,CJ la 100 Bang 3: Anh huo-ng cua cac ion Jen pic hap phu cua CJi 11) lon(lO'-M) Ip(^A) "^ffo 28 ! Khdngco 1.05 Zndl) Cu(ll) 1.05 Pbdll 0.8^ Fcdil 1,04 ;ion Fe(II), Fe(III), Zn(II) Cu(II) hdu ong anh huong den qud trinh xac dinh S|r CO mat ciia Pb(II) a mpt inong dp nhdt dinh se lam gidm^chieu [hip phu cua Cd(II) Pbdl) cung c6 rgtao phuc vdi Xylenol da cam Ham >i)(ll) thuc t^ thudng khd Idn so \di I nhien vdi ket qua khao sat anh tren ihi hodn loan cd ih^ xac dinh Cd(II) nalPb(II) mdu iplaiva gidi han phat hien • B 0>SC3 OOOTU SD; Do lech chudn: R: He so luang quan lanh gia mdt phuang phap phdn tich cdn n lap lai ciia phuang phap Mot phap phdn tich tdl can cd dp lap lai cao ien dpng nho Dc khao sat dp lap lai )i tien hanh thi nuhiem sau: V.„ = 2S = 10-' M C, 10"^^ M E, 1.2 V s toe dp phan cue 250 mV/s Ej = -0.4 s.Ciiui.Kiiiir^ 6.10'' M Ket qua cho lha\ (II) lap lai lot vdi lech chuan tuong ddi "LT ket qua thu duoc chiing tdi tim dugc )halhien cua phuong phap la 2.10"' M Jiing duong chuan /ao cac yeu td dd khao sat o' cac phan tren tien hanh xay dimg dudng chuan \ac dinh ing cac klioang ndng tir -10"'^ M den 'ai cac dieu kien tdi uu da khao sat o tren luona chudn nhu hinh Phuang trinh duang chuan: y - (0.053±0.0]6) - (0.106^0.0026).X R= 0.^9^ Hinh Duong chudn bieu dien ndng Cd'' lir "^ 10"'d^n 1.10"" M 11 Mot so ket qua xac dinh Cd(Il) mau Ap dung cac dieu kien da lim dugc a tren de phan tich Cd(ll) mpt sd mdu nuac Ddi vdi mdi nguon nudc Ia> den mau axit hoa Ipc mdu qua gidv Ipc cd kich thuoc 0.45 |.i them axit (3 ml HNO; dac cho lit mdu) lam ba> hai den cdn mudi dm, them 0.15 ml xylenol da cam 10"' M; 2.5 ml dem 0.1 M pha loang bang nudc cat lan tai 25 ml dem phan tich.duy ihutSc \ao nguon nudc cd the co lam giau hoac lang tho'i gian dien phan) thu dugc mot so ket qua Bang 4: Ket qua phan tich h.im lugng Cd t rong mot so ngudn nudc Mdu j ] - Cd"(pg/1) j KPHD KPHD " 0.16 0,05 0.55 ' 0.52 • 0.3^ 0.23 au 1: Mau nuoc ma\ khu vuc Cau Gia>-HN: Mau 2: Mau nuoc ma> Dinh Thon-HN au V Mau nuoc ma\ Nhan M>- HN: Mau 4: Mau nuoc ma> khu Dinh Cong- Ha Noi au 5; Mau nuoc \\6 Guam- HN Mau 6: Mau nuoc song Nhue- Ha Dong au 7: Mau nuoc gicng Thach Son-Phu Tho : Mau 8: Mau nuac Ho \'an- HN 'HD: Khong phat hien duoc a cho lha\ a cac mau nuoc ham lugng thdp hon gidi han cho phep [3] I V - K E T LUAN qud nchien ciiu tren cho tlid\ cd the su dung dien cue paste caebon bien linh bang HgO de phan tich ham lugng Cd(ll) cac mau theo phuong phap von ampe hoa lan hap phu Phep nghien cuu cung cho tha> su dung phuong phdp na> co dp nha> chpn loc vd :83 chinh xac cao quv trmh phan ticn luong ddi dan gian, rdt thich hop de phdn tich Cdfll) va cac ion kim loai nang cdc mau nudc _ ^AlLlEi: THAM KHAO i- Trdn Chuon Hu.en Dien hoc T 9(3) (2004) JCVN 5502-2003 - N^rdc cap sinh hoatveu cau chdt lugng ' paste caebon bien tinh ban^ HuO Na un- dung phan tich von ampe hoa tan anoi-phdn (Bai da gui Tap chi Phdn tich Hoa L\ va ^'"^ '^^^^'Nguyen Van Hop, Trdn Con^ Dung Nguyen Hai Phong Tu \ o n g Nghi Hoang Thp Tin Tap clii phan tich hoa ly \ii sinh Pompilia Suciu Marisol Vega Liviu ^ ^ ^ ^ ^ j^^^^^^^j ^f Pharmaceutical and Biomedical Analysis 23 - 106 ,2000) Jose A JuraJo-Gonzalez .Anai>i:ca Chimica Acta 48" 229 - 241 (200.-) ^ Chen'^"uo Hu Kanebimz Wu Xuan Da; • Shengsliui Hu.Talanta 60 P - 2-12003^ Kan-bin-Wu Shengshui Hu Junjie Fe: " Wen^Bai.'AnaUtica Chimica Acta ^8^ : : : _ -^1 ( 0 L Tdc gia lien he: Tran Chu-on