Bai 1:

Xac nh mau - mui - v cng - axit - kim

A. Xac nh mui 1. Nguyn tc: Dung phng phap cam quan xac nh c tnh va cng mui (mui t, mui clo, mui du...) 2. Dung cu, vt liu cn chun b: - Bnh tam giac nut nham dung tch 250ml - Cc thuy tinh dung tch 250ml - Mt knh ng h 3. Cach tin hanh: a. Xac nh mui 200C: Ly 100ml mu nc cn th 200C, cho vao bnh tam giac dung tch 250ml, y kn nut va lc (khoang 5 phut). Ngay sau o m nut ra va xac nh c tnh, mc cua mui b. Xac nh mui 600C: Ly 100ml mu nc cn th cho vao bnh tam giac dung tch 250ml, dung mt knh ng h y kn bnh tam giac va un nong cach thuy cho n 50-600C. Lc u bnh, dch knh ng h sang mt bn va nhanh chong xac nh c tnh va mc mui c. anh gia mc mui Mc mui cua nc 200C va 600C c anh gia va cho im theo quy nh theo bang sau:

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Mc mui

anh gia c im cua mui mc mui (im)

Khng mui Mui nhe

co Bng cam giac khng cam nhn c mui rt Ngi bnh thng khng nhn thy nhng phat hin c trong phong th nghim Ngi bnh thng nu chu y se phat hin c D nhn bit va gy cam giac kho chu Gy cam giac kho chu va luc

0 1

Mui nhe Co mui Co mui ro Mui

2 3 4 5

ung b lm giong rt Manh n ni khng th ung

ro c B. Xac nh v 1. Nguyn tc: Dung phng phap cam quan xac nh c tnh va cng cua v va v la Phn ra lam bn loai chnh: mn, chua, ngot va ng. Tt ca cac loai v khac nhn bit c u goi la v la. 2. Cach tin hanh: Cho mt t nc cn th vao ming, cho tng t mt, khng ung va gi trong ming t 3-5 giy nhn bit v 3. anh gia mc v Mc v va v la cua nc 20 0C c anh gia va cho im theo quy nh theo bang sau:

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Mc cua v va v la c tnh cua v va v la

anh gia mc cua v va v la (im)

Khng g V nhe V nhe Co v

co Bng cam giac khng cam nhn c v va v la rt Ngi bnh thng khng nhn thy nhng phat hin c trong phong th nghim Ngi bnh thng nu chu y se phat hin c D nhn bit va gy cam giac kho chu Gy cam giac kho chu va luc ung

0 1

2 3 4 5

Co mui ro

b lm giong Co v rt Manh n ni khng th ung ro c

C. Xac nh mau sc 1. Nguyn tc: Mau sc cua nc trong t nhin la do cac loai thc vt (mun), cac qua trnh sinh hoc, hoa hoc trong ngun nc tao ra. Dung phng phap so mau so sanh mau sc cua mu nc cn th vi mau nhn tao theo mau nc thin nhin. 2. Dung cu, hoa cht cn chun b: * Dung cu:

- May so mau co bc song =413nmng ong co dung tch 100ml ng hut cac loai Phu thuy tinhTrang 4

-

Giy loc. Dung dch tiu chun chnh (dung dch s 1)

* Hoa cht: Cn chnh xac 0,0875g kali dicromat (K2Cr2O7), 2g coban sunfat (CoSO4) va 1ml axit sunfuaric (d=1,84g/cm3) hoa tan vao trong mt t nc ct. nh mc thanh 1000ml. Dung dch nay tng ng vi mau 5000. Dung dch axit sunfuaric loang (dung dch s 2) Dung nc ct pha loang 1ml axit sunfuaric m c (d=1,84g/cm3) n 1000ml. 3. Cach tin hanh * Lp ng chun: Theo bang sau: S TT ng Thuc th Dung dch s 1 (ml) Dung dch s 2 (ml) mau 0 20 0 00 2 19 8 50 4 19 6 19 8 19 10 19 12 18 14 18 16 18 20 18 24 17 28 17 1 2 3 4 5 6 7 8 9 10 11 12

6 4 2 0 8 6 4 0 6 2 0 0 0 0 0 0 0 0 0 10 15 20 25 30 35 40 50 60 700

thang mau n nh (t 5-10 phut) ri tin hanh o hp thu hay thu quang trn may so mau bc song =413nm. Ghi mt quang hoc thu quang theo th t cua tng ng. Ve th biu din mi quan h gia hp thu hoc thu quang (truc tung) vi mau cua tng ng (truc hoanh).Trang 5

* Tin hanh th: Ly 100ml mu nc cn th (a loc) ri tin hanh o hp thu hay thu quang trn may so mau bc song = 413nm. Da vao th xac nh mau cua mu nc th. Nu mu th co mau >700 th phai pha loang bng nc ct. Thng thng cac ngun nc t nhin co mau khac nhau t 150 n 250 va nc ao h t 400 n 600. D. Xac nh cng tng s 1. Nguyn tc Da trn vic tao hp cht phc bn vng cua EDTA (Trilon B) vi cac ion Ca2+ va Mg2+ co trong mu nc trong mi trng pH=10 Cac cht can tr: ng, kem, mangan va cac mui cacbonnat, hydrocacbonat 2. Dung cu, hoa cht cn chun b * Dung cu: - Bnh tam giac khng nut dung tch 250ml - ng chun 25ml, ng hut cac loai * Hoa cht: - Dung dch EDTA 0,05N: Cn chnh xac 9,306g EDTA hoa tan vao trong mt t nc ct, nh mc thanh 1000ml. Nu dung dch b uc phai em loc trc khi dung. - Dung dch m: Hoa tan 10g amoni clorua (NH4Cl) vao trong mt t nc ct, thm 50ml dung dch amoni hydroxit 25% va thm nc ct n 500ml. Bao quan trong chai thuy tinh y kn. - Cht ch th:

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Cn 0,25g ET- OO trn vi 50g NaCl a c sy kh, nghin nho. Bao quan trong chai thuy tinh va y kn. 3. Cach tin hanh Ly chnh xac 100ml mu nc th cho vao bnh tam giac dung tch 250ml, thm vao 5ml dung dch m NH4Cl + NH4OH lc u, cho lng nho cht ch th ET-OO vao (ch bng hat gao). em chun bng dung dch EDTA 0,05N, khi mu th chuyn t mau o nho sang mau xanh bic th kt thuc chun . Ghi th tch dung dch EDTA tiu tn cho qua trnh chun . 4. Tnh toan kt qua cng tng s (X) cua mu th c tnh theo cng thc sau:X = v.N .1000 V

(mlg/l)

Trong o: - v: th tch dung dch EDTA tiu tn cho qua trnh chun (ml) - N: nng cua dung dch EDTA em chun (N) - V: th tch mu nc th (ml) E. Xac nh axit axit c nh ngha la ham lng cua tt ca cac cht co trong nc tham gia phan ng vi cac kim manh nh NaOH hoc KOH. axit cua nc c xac nh bng lng kim dung trung hoa nc. i vi cac loai nc t nhin thng gp, trong a s cac trng hp, axit phu thuc vao ham lng kh CO2 trong nc. Cac cht mun va axit hu c nu co trong ncTrang 7

cuing tao nn mt ph axit cua ngun nc. Trong tt ca cac trng hp o pH cua nc thin nhin thng khng nho hn 4.5 i vi cac loai nc thai, ham lng cua cac axit manh t do thng kha lain, khng nhng vy trong nc thai thng cha cac mui tao bi baz yu va cac axit manh nn axit cua nc cung cao. Trong trng hp nay, pH cua nc thng khng ln hn 4.5 c goi la axit t do. xac nh axit cua nc, ngi ta thng chun axit bng dung dch NaOH hoc KOH. Lng dung dch chun tiu tn at c pH 4.5 tng ng vi lng axit t do co trong nc. Nu pH cua mu nc lain hn 8.3 co th kt lun rng axit cua mu nc bng khng. 1. Dung cu, hoa cht Bnh tam giac ng chun , ng hut cac loai Cac dung dch chun NaOH 0.1M hoc 0.01M Dung dch Metyl dacam 0.05%. Hoa tan 0.05g ch th trong 100ml nc nong.

Cht ch th:

- Dung dch Phenolphtalein 0.5%. Hoa tan 0.5g cht ch thtrong 50ml ru etanol 960 va b sung thm 50ml nc nong. 2. Trnh t tin hanh Nu th s b dung giy ch th tng hp thy trong mu nc co axit t do (pH < 4.5) th ngoai axit toan phn ( axit chung) cn xac nh thm axit t do trong trng hp mu khng co lng ang k cac mui thuy phn. a. axit t do

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Ly 100ml mu cho vao bnh tam giac dung tch 250ml, thm vao o 2 -3 giot metyl dacam va chun bng dd NaOH 0.1N n khi dung dch chuyn t mau o sang mau vang da cam. Nu dung may o pH th chun n pH = 4.5. b. axit toan phn u tin tin hanh chun nh hng nh sau: ly 100ml mu nc cho vao bnh non dung tch 250ml, thm vao t 2 - 3 giot phenolphtalein va chun bng dung dch NaOH 0.01N n khi dung dch chuyn sang mau hng nhat. Nu dung may o pH th vic kt thuc chun khi pH = 8.3. Sau o tin hanh chun chnh xac nh sau: Ly mu nc tai ch cho vao bnh ong hnh tru co dung tch 100ml, dung pipet ly 100ml mu cho vao bnh non co dung tch 250nl, thm vao 5 - 10 giot phenolphtalein ri chun bng dung dch kim 0.01N cho n khi dung dch xut hin mau hng khng b mt mau trong khoang thi gian 30s. T kt qua cua ln chun trn, tha nhanh lng NaOH xung gn im tng ng ri mi cho cht ch th va tip tuc chun chm cho n khi xut hin mau hng. Nu dung may o pH th kt thuc chun khi pH = 8.3. 3. Tnh toan kt qua axit t do (m): m = (a.0,1.1000)/V (mgdl/l) axit toan phn (p) p = (b.0,01.1000)/V (mgdl/l) Trong o: - a: Lng NaOH i mau, ml - b: Lng NaOH 0.01N tiu tn n khi phenolphthalein i mau, mlTrang 9

0.1N tiu tn n khi metyl da cam

- V: Th tch mu nc, ml F. Xac nh kim kim c nh ngha va xac nh tng ng axit. kim cua nc la ham lng cac cht phan ng viaxit manh, tc la phan ng vi cac ion H+. xac nh kim cua nc ngi ta thng s dung phng phap trung hoa, dung dung dch axit manh chun . kim c biu th bng s mili ng lng gam axit tiu tn ng vi 1 lt nc. i vi cac ngun nc thin nhin kim phu thuc vao ham lng cac mui Hydrocacbonat cua kim loai kim va kim th. Trong trng p nay pH cua nc thng khng vt qua gia tr 8.3 va kim chung thc t se trung vi cng cacbonat va tng ng vi ham lng cua hydrocacbonat. Nu trong nc cha ham lng khng qua nho cac mui cacbonat tan c, cung nh cac hydroxit tan c th pH cua ion nc se lain hn 8.3. Trong trng hp nay, kim ng vi lng axit cn dung giam pH cua nc xung gia tr 8.3 c goi la kim t do (p) cua nc. V km toan phn (m) va kim t do (p) ty l vi ham lng cua cac ion HCO3-, CO32-, OHnn da vao cac gia tr p, m xac nh c co th xac nh gian tip cac ion o. xac nh kim cua nc, ngi ta chun bng dung dch axit manh. Lng dung dch chun tiu t at ti pH bng 8.3 tng ng vi kim t do p, lng axit cn thit chun n pH bng 4.5 tng ng vi kim toan phn m. Nu pH cua nc nho hn 4.5 th kim cua nc bng khng.Trang 10

xac nh c im tng ng cua phep chun co th dung cac cht ch th axit - baz hoc dung may o pH. Cn phai chu y xac nh kim, c bit la kim t do ngay sau khi ly mu nc va dung phng phap in th nu mu nc co mau xanh hoc b vn uc. Cung nh xac nh axit, trong trng hp xac nh im tng ng bng cht ch th, th s co mt cua Clo t do trong nc se ngn can s xac nh. Thng loai tr bng cach thm 1 lng Na2S2O3. Lng CO2 qua cao cung se anh hng n s chuyn mau cua cac cht ch th. Trong trng hp nay thng dung mt lng khng kh sach ui lng CO2. 1. Hoa cht - Dung dch chun HCl 0.1N. - Phenophtalein, dung dch ch th 0.5% - Metyl dacam, dung dch 0.05% - Cht ch th hn hp, hoa tan 0.03g metyl o va 0.2g Bromerezot xanh trong 150ml dung dch C2H5OH 96% va thit lp pH cua dung dch th nao o c dung dch co mau xam ti. 2. Trnh t tin hanh kim t do, ly 100ml mu nc cho vao bnh non co dung tch 250ml, thm vao o vai giot ch th phenolphthalein va chun bng dung dch HCl 0.1N cho n khi dung dch mt mau hoan toan. Nu chun bng phng phap in th va cc thuy tinh th kt thuc chun tai pH = 8.3 kim toan phn, ly 100ml mu nc cho vao bnh tam giac 250ml va thm vao vai giot ch th metyl dacam, thi khng kh sach loai bo CO2 trong vai phut va chun bng bng dung dch HCl 0.01N cho n khi dung dch chuyn t mau vang sang o da cam. Va chuyn sang mau xam ti nu

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dung ch th hn hp. Nu chun bng phng phap in th va cc thuy tinh th chun n pH = 4.5 3. Tnh toan kt qua kim t do (p): p = (a.0,1.1000)/V (mgdl/l) kim toan phn (m) m = (b.0,01.1000)/V (mgdl/l) Trong o: - a: Lng HCl 0.1N tiu tn, ml - b: Lng HCl 0.01N tiu tn, ml - V: Th tch mu nc, ml

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Bai 2:

Xac nh SS, Cl-, SO42A. Xac nh ham lng SS Cht rn l lng bao gm cac cht v c, hu c khng tan trong nc. 1. Nguyn tc: Tin hanh loc chnh xac mt th tch mu nc, ri em sy kh giy loc co cn n khi lng khng i. Cn giy loc co cn, se cho bit ham lng cht l lng co trong mu nc. 2. Dung cu, thit b cn chun b: * Dung cu: Giy loc, phu thuy tinh, ua thuy tinh, cc thuy tinh, bnh cach m. * Thit b: Tu sy, cn phn tch ( chnh xac 0,1 mg) 3. Tin hanh: Lp dung cu nh hnh ve 1. 2. 3. 4. 5. 6. Gia Phu thuy tinh Giy loc Cc thuy tinh hng nc a loc Cc thuy tinh ng mu nc ua thuy tinh4 1 2 6 5

Giy loc c sy kh, ngui trong bnh cach m n nhit phong. Cn giy loc trn cn phn tch (co chnh xac 0,1 mg) ta c: P1.Trang 13

Ly 100 ml mu nc th (th tch mu nc th co th thay i tuy theo ngun), loc qua phu thuy tinh co lot giy loc. Loc xong, ch cho rao nc, gp giy loc co cn lai, cho vao chen s. Tin hanh sy trong tu sy nhit : 105-1100C trong thi gian 1 n 2 gi. Ly ra ngui trong bnh cach m n nhit phong. Cn giy loc co cn ta c: P2 4. Tnh toan kt qua: Ham lng cht rn l lng (X) co trong mu nc c tnh theo cng thc sau: (P2 - P1) X= x1000 mg/l

VTrong o: P1: Khi lng giy loc a loc, tnh bng mg P2: Khi lng giy loc co cn sau khi sy kh, tnh bng mg V: Th tch mu nc em loc, tnh bng ml B. Xac nh ham lng clorua 1. Nguyn tc Da trn vic kt tua ion Cl- trong mi trng trung tnh hoc bazo yu bng dung dch bac nitrat vi ch th kali cromat. Sau khi kt tua bac clorua, tai im tng ng se tao bac cromat. Khi o mau vang cua dung dch se chuyn thanh mau da cam nu. chnh xac cua phng phap 1 - 3 mg/l. 2. Dung cu hoa cht cn chun b * Dung cu: - Bnh tam giac khng nut dung tch 250ml - ng chun 25mlTrang 14

sy kh trc khi

- ng hut cac loai * Hoa cht: - Dung dch AgNO3 0,05N Cn chnh xac 8,4934g AgNO3 (tinh khit phn tch) a c sy kh 1050C. Hoa tan trong mt t nc ct va nh mc thanh 1000ml. Bao quan trong chai nu va bong ti - Thuc th K2CrO4 5% Cn 5g K2CrO4 hoa tan trong 95ml nc ct 3. Cach tin hanh Ly chnh xac 100ml mu nc th cho vao bnh tam giac dung tch 250ml. Nu mu nc phan ng axit hoc kim th trung hoa bng dung dch kim hoc axit theo phenolphtalein. Sau khi trung hoa xong, thm vao vai giot axit dung dch mt mau hng (nu co). Nu mu nc th co pH = 7 - 10 th khng cn x ly trc. Thm vao vai giot dung dch kali cromat Chun bng dung dch bac nitrat 0,05N cho n khi dung dch xut hin mau da cam nu th kt thuc chun . Ghi th tch bac nitrat tiu tn cho qua trnh chun . Tin hanh mt th nghim trng vi 100ml nc ct va tin hanh tng t. 4. Tnh toan kt qua Ham lng clorua (X) cua mu th c tnh theo cng thc sau:X =

(V1 V2 ).N .35450V

(mg/l)

Trong o: - V1: th tch dung dch AgNO3 tiu tn cho qua trnh chun i vi mu th (ml) - V2: th tch dung dch AgNO3 tiu tn cho qua trnh chun i vi mu trng (ml)Trang 15

- N: nng cua dung dch AgNO3 em chun (N) - V: th tch mu nc th (ml) C. Xac nh ham lng sunfat (SO42-) - Phng phap trong lng 1. Nguyn tc Trong mi trng axit (HCl), ion Bari phan ng vi gc sunfat co trong mu nc tao thanh kt tua barisunfat. Tin hanh loc, ra ri sy kh kt tua nhit 1050C n khi lng khng i. ngui n nhit phong trong bnh cach m ri cn kt tua. T y ta co th xac nh c ham lng sunfat co trong mu nc th. Cac yu t can tr: Cac hp cht hu c: vi ham lng ang k co th hp phu hoc ng kt tua. 2. Dung cu hoa cht cn chun b * Dung cu:-

Cn phn tch co chnh xac 0,1mg Tu sy Bnh cach m Dung cu thuy tinh cac loai Axit clohidric 6mol/lt Hut 500ml HCl m c (d=1,18g/ml) hoa tan vao trong nc ct n 1000ml. Bao quan trong lo thuy tinh hoc bnh polyetylen.

-

* Hoa cht:

-

Dung dch bari clorua 100g/lt Cn 100g BaCl2.2H2O cho vao cc thuy tinh va hoa tan bng nc ct nong n 1000ml. Bao quan trong chai thuy tinh.Trang 16

-

Dung dch NaOH 5mol/lt Cn 20g NaOH cho vao cc thuy tinh va hoa tan bng nc ct n 100ml. Bao quan trong chai polyetylen.

-

Dung dch bac nitrat 0,1N: Cn 17g AgNO3 hoa tan vao trong mt t nc ct va nh mc thanh 1000ml. Bao quan trong chai mau nu.

-

Dung dch metyl da cam 1g/lt: Cn 0,1g metyl da cam hoa tan trong tng t nc ct n 100ml

-

Dung dch etanola (95% etanol, 5% metanol)

3. Cach tin hanh a. Chun b mu: - Ly mu: ly mu va bao quan trong chai thuy tinh hoc polyetylen va tin hanh phn tch ngay trong ngay hoc bao quan khng qua mt tun nhit t 3-50C. nc y chai loai ht khng kh tranh b oxy hoa mu cha sunfit hoc sunfua. - Chun b mu th: yn cho cht l lng co mu nc th lng xung. Co th loc mu nc th bng giy loc, xp, mn va khng tro. Ly phn nc trong phn tch. b.Cach tin hanh: - Ly chnh xac mt th tch mu nc th cho vao cc thuy tinh dung tch 500ml, thm 2 giot ch th metyl da cam va trung hoa mu th bng HCl hoc NaOH tuy thuc vao pH ban u. - Thm vao 2ml dung dch HCl khuy u ri un si trong thi gian 5 phut. - Sau khi un si ma trong mu th co nhng cht khng tan th tin hanh loc hn hp nong qua giy loc xp, mn va khng tro. Ra giy loc vai ln bng nc ct nong, gpTrang 17

nc ra vao dch loc, chuyn toan b dung dch vao cc thuy tinh 500ml. - un si, dung pipet thm t t va khuy u 10ml dung dch bari clorua nong (khoang 800C) vao trong trong dung dch. un nong dung dch t nht 1 gi, y np, ngui va yn qua em nhit khoang 500C. - Sy kh giy loc nhit 1050C trong mt gi va ngui trong bnh cach m, ri tin hanh cn ta co khi lng giy loc: m1 gam - Tin hanh loc dung dch trn phu thuy tinh co lot giy loc. Ra kt tua trn giy loc vai ln bng nc ct lanh (khng cha clorua) cho n ht clorua (th bng dung dch AgNO3). - Sy giy loc co cha kt tua nhit 1050C n khi lng khng i trong mt gi va ngui n nhit phong trong bnh cach m va em cn. Ta co khi lng la: m2 gam - Tin hanh tng t nh trn vi mt mt nc ct. Ta co: m0 gam. Co th rut ngn qua trnh sy nu ra kt tua bng 5ml etanola 3 ln 4. Tnh toan kt qua Khi lng cua bari sunfat co trong mu nc th c tnh theo cng thc sau:

[SO ] = m2 4

2

( m0 + m1 ).0,4116 V

mg/l

Trong o: - m0: khi lng mu th trng, gam - m1: khi lng giy loc (khng co kt tua), gam - m2: khi lng giy loc va kt tua, gam - V: th tch mu nc th, mlTrang 18

- 0,4116: h s trong lng.

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Bai 4:

Xac nh DO, BOD5A. Xac nh oxy hoa tan - Phng phap Winkler 1. Nguyn tc Thm dung dch kim cha iodua va mui mangan (II) vao mu nc se thu c kt tua trng mangan hidroxit. Kt tua nay lp tc b oxi hoa tan trong nc oxi hoa thanh hp cht magan co mc oxi hoa cao hn, mau nu. Trong mi trng axit, hp cht nay co kha nng oxi hoa iodua tao ra iot. Dung dung dch tiu chun natri thiosunfat chun lng iot sinh ra, t o se tnh c ham lng oxi hoa tan trong mu nc 2. Dung cu, hoa cht a. Dung cu: Chai thuy tinh nut mai dung tch t 100-300 ml Cn phn tch co chnh xac 0,1mg ng hut cac loai Dung dch A:

b. Hoa cht: Hoa tan 425g mangan clorua (MnCl2.4H2O) hoc 480g mangan sunfat (MnSO4.4H2O) bng mt t nc ct trong cc thuy tinh ri nh mc thanh 1000ml. Dung dch B: Hoa tan 150g kali iodua (KI) hoc 136g natri iodua (NaI) trong 200ml nc ct. Hoa tan 500g natri hydroxit (NaOH) hoc 700g kali hidroxit (KOH) trong 500ml nc ct. Trn ln hai dung dch vi nhau ri pha loang thanh 1 lt. Axit clohidric HCl 2:1 Trn hai th tch dung dch axit clohidric HCl m c (d=1,19) vi mt th tch nc ct.Trang 20

-

Dung dch h tinh bt 5%:

Hoa tan 0,5g tinh bt vao trong 100ml nc ct ri un n si. Dung dch c pha ch tng ngay s dung. Mun lu phai thm cht bao quan (ru amilic, clorofom, axit salisilic).-

Dung dch Natri thiosunfat Na2S2O3 0,02N : chun.

Pha bng ng

3. Ly mu - Mu ly xac nh oxi hoa tan phai ai din cho mi trng nc cn nghin cu. Thit b ly mu cn bao am khng b suc bot kh. Khi ly ln khoi mi trng nc phai y nut cht. - Cn phn tch mu ngay sau khi ly mu. Nu khng co iu kin phn tch ngay th phai thc hin c nh oxi. 4. Cach tin hanh Dung xiphong chuyn mu nc vao y chai sao cho tranh suc bot, u xiphong sat ay chai, trong khi chai y dn th t t rut xiphong ln va tip tuc cho chay tran. Dung ng hut thm vao chai 1ml dung dch A. Dung ng hut khac thm vao chai 1ml dung dch B. Khi thm, u ng hut gia chai ri va cho dung dch vao va rut ng hut ln. y kn nut chai sao cho khng co bot kh. Lc ln vong chai nhiu ln ri yn cho kt tua lng xung. Bao quan chai trong ch mat va ti (khoang 10 phut) ri em phn tch tip. Thm vao 5ml dung dch HCl 1:2, yn u ng hut xung gn lp kt tua ri va cho dung dch HCl 1:2 chay ra va rut dn ng hut ln. Phn cht long trong sut pha trn tran ra ngoai khng anh hng n kt qua phn tch. y kn nut chai va lc ln vong chai nhiu ln cho n khi hoa tan ht kt tua.

Trang 21

Chuyn toan b dung dch trong chai vao bnh tam giac co dung tch 500ml, trang chai bng mt t nc ct ri tp trung ca vao bnh non. Chun bng dung dch natri thiosunfat (Na2S2O3) 0,02N ti mau vang nhat. Thm 1ml dung dch h tinh bt vao va tip tuc chun n va mt mau th kt thuc chun (khng quan tm n s lai mau). Co th ly chnh xac 50ml dung dch a axit hoa trong chai chuyn vao bnh non dung tch 250ml chun . Cac bc c tin hanh nh trn. 4. Tnh toan kt qua Trong trng hp chun toan b th tch mu nc em c nh oxi th nng oxi hoa tan c tnh nh sau:X = 8.N .n .1000 V 2

mg/l

Trong o: 8: ng lng gam cua oxi N: nng ng lng gam cua dung dch natri thiosunfat n: th tch dung dch natri thiosunfat tiu tn cho qua trnh chun ml. V: th tch chai c nh oxi 2: th tch mu nc tran ra ngoai khi c nh oxi Trong trng hp ch chun 50ml dung dch trong chai th nng oxi hoa tan c tnh nh sau:X = 8.N .n .1000 50 .(V 2)

mg/l

B. Xac nh BOD5 1.Muc ch - Nguyn tc a. Muc chTrang 22

Mun bit lng oxy tiu thu bi VSV va cac cht hu c ( anh gia bn cua nc) ta tm hiu s gia lng oxy ngay sau khi ly mu nc va lng oxy sau 5 ngay. b. Nguyn tc Trung hoa mu nc th va pha loang bng nhng lng nc khac nhau cua mt loai nc giau oxy va cha cac vi sinh vt hiu kh, co hoc khng cha cht c ch s nitrat hoa. U nhit xac nh trong mt thi gian xac nh 5 ngay, trong bong ti, trong bnh hoan toan kn va nut kn. Xac nh nng oxy hoa tan trc va sau khi u trong mt lt nc. Tin hanh ng thi kim tra vi dung dch chun cua gluco va axit glutamic 2. Dung cu, hoa cht cn chun b: * Dung cu: Tu u iu chnh c nhit , may o oxy hoa tan, may suc kh, cc thuy tinh 1000ml, bnh tam giac co nut 250 ml * Nc pha loang: Trong trng hp mu nc qua bn, lng oxy tiu thu vut qua lng oxy hoa tan trong mu nc do o ta pha loang mu nc th bng nc a bao hoa oxy. Dung dch m photphat: (*) KH2PO4 K2HPO4 Na2HPO4 NH4Cl 8,5 g. 21,75 g 33,4 g 1,7 g

Cac hoa cht trn pha vi nc ct thanh 1000ml (goi la dung dch HPO4-2 co pH=7,2 khng cn phai iu chnh g thm). Magie sunfat heptahidrat 22,5g/l (**)Trang 23

Hoa tan 22,5g MgSO4.7H2O trong nc ct. Pha thanh 1000ml va lc u Canxi clorua 27,5g/l. (***) Hoa tan 27,5g canxi clorua khan (CaCl2) trong nc. Pha thanh 1000ml va lc u St (III) clorua hexahidrat 0,25g/l (****) Hoa tan 0,25g st (III) clorua hexahidrat (FeCl3.6H2O) trong nc. Pha thanh 1000ml va lc u. Hut 1ml mi loai dung dch (*), (**), (***), (****) cho vao 500ml, lc u va pha loang thanh 1000ml. Tao nhit 200C cho dung dch va iu ch c, ri suc kh trong 1 gi sao cho nng oxy hoa tan t nht phai at 8mg/l. Chu y khng lam nhim bn dung dch, c bit la cac cht hu c, cht oxy hoa va kim loai. * Nc cy: Ban thn mu nc khng u cac vi sinh vt cn thit, phai dung nc cy tao c bng cach sau: Nc thai sinh hoat, ly t cac cng thoat nc cua cac vung dn c khng b nhim bn bi cac ngun thai cng nghip. Nc c lng trc khi dung. 3. Cac bc tin hanh: Dung nc a bao hoa oxy pha loang chnh xac mu nc th (ty l pha loang cho bang). mu nc a pha loang vao 3 bnh tam giac dung tch 250ml (khng c phep tn tai bot kh thanh chai). Ly 1 bnh tin hanh o ngay lng oxy hoa tan (t=0), hai bnh con lai em u trong bong ti nhit : 200C 1. Sau 5 ngay tin hanh o lng oxy hoa tan con lai (t=5ngay) Mu trng c tin hanh ng thi vi nc pha loang a cy cac vi sinh vt. pha loang khuyn ngh xac nh BOD5Trang 24

BOD5 d oan (mg/l) 3-6 4 - 12 10 - 30 20 - 60 40 - 120 100 - 300 200 - 600 400 - 1200 1000 - 3000 2000 - 6000 Ghi chu

H s pha loang Gia 1 va 2 2 5 10 20 50 100 200 500 1000

Kt qua c lam tron n 0,5 0,5 0,5 1 2 5 10 20 50 100

Ap dung cho R R, E R, E E S S, C S, C I, C I I

R: Nc sng E: Nc thai c lam sach sinh hoc S: Nc thai c lam trong hoc nc thai cng nghip b nhim nhe C: Nc thai cha x ly I: Nc thai b nhim nng Chu y: Tin hanh xac nh BOD ngay sau khi ly mu nc 4. Tnh toan kt qua Ham lng BOD5 (lng oxy tiu thu bi cac VSV sau 5 ngay) c tnh theo cng thc:

[ BOD 5 ] = ( C1 C2 ) V1 Ve ( C3 C4 ) . V1 V1 Ve

(mg/l)

Trong o: - C1: nng oxy hoa tan cua mu th tai thi im t=0 (mg/l) - C2: nng oxy hoa tan cua mu th tai thi im t=5 ngay (mg/l) - C3: nng oxy hoa tan cua mu trng tai thi im t=0 (mg/l)

Trang 25

- C4: nng oxy hoa tan cua mu trng tai thi im t=5 ngay (mg/l) - Ve: th tch cua mu th em pha loang (ml) - V1: tng th tch cua mu th va nc pha loang (ml)

Trang 26

Bai 5:

Xac nh CODMn, CODCrA. Phng phap kali Pemanganat (CODMn) 1. Nguyn tc: -

Da vao kha nng oxy hoa manh cua KMnO 4 trong mi Da vao lng KMnO4 cho vao mu nc th ban u va lng KMnO4 con lai sau phan ng ta co th xac nh c lng cht hu c co trong mu nc th.

trng axt.

C ch phan ng:-

Trong mi trng axit MnO4- tham gia phan ng oxy hoa cac hp cht hu c: MnO4- + 5e + 8H+ = Mn2+ + 4H2O

-

Lng MnO4- con d sau phan ng c xac nh bng dung dch (COOH)2 2MnO4- + 5(C2O4)2- + 16H+ = 2Mn2+ + 10CO2 + 8H2O

2. Dung cu, hoa cht cn chun b: * Dung cu: Bp in, bnh tam giac 250 ml, nhit k 1000C, buret 25 ml, pipet cac loai. * Hoa cht: KMnO4 (COOH)2 H2SO4 3. Cac bc tin hanh: Cho vao bnh tam giac dung tch 250 ml (a ra sach va sy kh) 50 ml mu nc cn th (nu mu nc th co nng cht hu c ln hn 10 mg/l th phai pha loang); thm vao 5ml H2SO4 1:2; thm ung 10 ml dung dch KMnO4 0,01N (mu nc co mau hng). Sau o un si 10 phut trn bp in, nhc xung ch cho nhit ha xung 80 - 900C ri thm vao 10 mlTrang 27

0,01N 0,01N 1:2

dung dch (COOH)2 0,01N lc u cho mu nc mt mau (khng mau) ri dung dung dch KMnO4 0,01N chun cho n khi mu nc chuyn t khng mau sang mau hng nhat th kt thuc chun . Ghi kt qua lng KMnO4 a tiu tn: V1. Thay mu nc th bng 50 ml nc ct th nghim mt mu trng. Cac bc tin hanh th nghim c thc hin tng t nh trn; lng KMnO4 0,01N tiu tn la:V2 Chu y: Tin hanh chun nhit 80-900C 4. Tnh toan kt qua: Ham lng COD (lng oxy cn thit oxy hoa cht hu c) co trong mu nc c tnh theo cng thc sau:

[ X ] = (V1 V2 ).N .8 .1000V

(mg/l)

Trong o:- V1: Lng dung dch KMnO4 0,01N tiu tn chun mu nc th (ml) - V2: Lng dung dch KMnO4 0,01N tiu tn chun mu nc ct (ml) - N: Nng ng lng cua dung dch KMnO4. - V: Th tch mu nc em th (ml) - 8: ng lng gam cua oxy (g) B. Phng phap Kali dicromat (CODCr) 1. Nguyn tc: Cho cac cht hu c trong mu nc th tac dung vi hn hp axit cromic va axit sunfuaric luc un si vi cht xuc tac la Ag+. un mu nc th vi thuc th trong ng sinh han hi lu va chun lng bicromat d sau phan ng vi dung dch st-amoni sunfat (NH4)2 Fe(SO4)2.6H2O C ch phan ng:-

Trong mi trng axit Cr2O72- tham gia phan ng oxy hoa cac hp cht hu c:Trang 28

Cr2O7-2 + 6e + 14H+ = 2Cr3+ + 7H2O-

Lng Cr2O72- con d sau phan ng se c xac nh bng dung dch st-amoni sunfat Cr2O72- + 6Fe2+ + 14H+ = Cr3+ + 6Fe3+ + 7H2

2. Dung cu, hoa cht cn chun b: * Dung cu: hut cac loai * Hoa cht: Dung dch kali bicromat 0,25N Sy K2Cr2O7 nhit 1050C trong 2 gi. Cn chnh xac 12,259g va hoa tan trong mt t nc ct sau o nh mc thanh 1000ml. Dung dch St-amoni sunfat 0,25N Cn chnh xac 98 g St-amoni sunfat va hoa tan vao trong mt t nc ct. Thm 20ml H2SO4 m c sau o nh mc thanh 1000ml Cht ch th Feroin: Cn 1,485 gam 1,10 phenanthroline monohydrat, 695mg FeSO4.7H2O va hoa tan vao trong mt t nc ct ri nh mc thanh 100ml. Axit sunfuaric m c (d=1,84) Bac sunfat tinh th Thuy ngn (II) tinh th. Bp in, ng sinh han hi lu, bnh cu hai c 250ml, bnh tam giac 500ml, ng chun 25 ml va ng

3. Cach tin hanh: Ly 50 ml mu nc cn th cho vao bnh cu 2 c dung tch 250ml, thm 20ml dung dch kali dicromat 0,25N (khi lng cht hu c qua ln phai giam bt th tch mu nc th); thng qua c bnh cu thm t t tng lng nho 30 ml H 2SO4 m c; thm vao 1g Ag2SO4, cui cung cho vai vin a bot riTrang 29

lp ng sinh han hi lu, un si nhe va gi si trong 2 gi. Lam ngui bnh, thao ng sinh han va dung 25ml nc ct ra thanh ng sinh han, chuyn dung dch vao bnh tam giac dung tch 500ml va trang bnh cu vai ba ln bng nc ct. Sau o thm nc ct va u 250ml, thm 3-4 giot cht ch th mau feroin va dung dung dch st-amoni sunfat 0,25N chun lng kali dicromat d. Vic chun kt thuc khi dung dch chuyn t mau xanh mc sang o nu. Tin hanh mt th nghim trng vi 50ml nc ct va tin hanh tng t. Nu trong mu nc th co ham lng Cl- cao th cho thm vao 1g Hg2+ 4. Tnh toan kt qua: Ham lng COD (lng oxy cn thit oxy hoa cht hu c) co trong mu nc c tnh theo cng thc sau:

[ X ] = ( a b ).N .8 .1000V

(mg/l)

Trong o: - a: Th tch dung dch st-amoni sunfat tiu tn dung chun mu trng (ml) - b: Th tch dung dch st-amoni sunfat tiu tn dung chun mu th (ml) - N: Nng ng lng cua dung dch st-amoni sunfat - V: Th tch mu nc em th (ml) 8: ng lng gam cua oxy (g)

Trang 30

Bai 6:

Xac nh ham lng Poliphotphat PO431. Nguyn tc Phng phap nay da trn vic thuy phn poliphotphat trong mi trng axit chuyn thanh octophotphat hoa tan va xac nh theo phng phap so mau di dang phc photphotmolipdic b kh thanh mau xanh. nhay cua phng phap 0,01 mg/l 2. Dung cu, hoa cht * Dung cu: Bp cach thuy Cc thuy tinh cac loai ng hut cac loai May so mau Dung dch tiu chun chnh:

* Hoa cht: Cn chnh xac 0,7165g KH2PO4 (loai tnh khit hoa hoc) cho vao cc thuy tinh va hoa tan trong mt t nc ct. nh mc thanh 1000ml Ta co: 1ml dung dch co 0,5mg PO43Pha loang dung dch tiu chun chnh trn co: 1ml dung dch co 0,001mg PO43Dung dch amoni molipdat (dung dch axit yu): Cn 10g (NH4)6Mo7O24.4H2O cho vao cc thuy tinh va hoa tan trong 400ml nc ct, thm 7ml H2SO4 m c (98%). Bao quan trong chai polietylen co mau sm. Dung dch bn hn 3 thang. Sau khi chun b 48 gi mi em s dung. Dung dch thic diclorua chnh:Trang 31

Cn 1,95g thic iclorua (SnCl2.2H2O) dang tinh th hoa tan vao trong 18,4 ml HCl m c, khng cha asen ri cho vao 50ml nc ct. Trn u cn thn va bao quan trong chai thuy tinh co trang parafin. Co th s dung sau khi chun b. Dung dch lam vic cua thic diclorua Hut 2,5ml dung dch chnh trn va pha loang bng nc ct n 10ml.-

Dung dch H2SO4 37%: Ly 337ml H2SO4 m c (loai 98%) hoa tan tng t

mt vao trong 600ml nc ct. ngui ri pha thanh 1000ml. 3. Cach tin hanh a. Lp ng chun: Chun b thang mu theo bang sau: Dung dch (ml) Dung dch co 0,001mg PO43-/ml Nc ct Dung dch amoni molipdat (dung dch axit yu) Lc u, yn 5 phut ri thm Dung dch lam vic cua thic diclorua Lng PO43- trong mi cc thuy tinh (mg) Nng PO43- (mg/l) 0,1 0,1 0,00 05 0,01 0,1 0,00 1 0,02 0,1 0,00 2 0,04 0,1 0,00 5 0,1 0,1 0,1 0 0 S th t cc thuy tinh 1 2 3 4 5 0,5 1,0 2,0 5,0 10,0 6 20,0

nh mc thanh 50ml 1 1 1 1 1 1 1

0 0

0,01 0,2

0,02 0,4

thang mau n nh (t 5-10 phut) ri tin hanh o hp thu hay thu quang trn may so mau bc song =

Trang 32

690 - 722 nm. Ghi mt quang hoc thu quang theo th t cua tng cc. Ve th biu din mi quan h gia hp thu hoc thu quang (truc tung) vi ham lng PO 43- cua dung dch chun (truc hoanh). b. Xac nh ham lng PO43- trong mu nc th: Cho 50ml mu nc cn th vao trong cc thuy tinh 250ml (nu ham lng PO4-3 ln th phai pha loang) thm vao 2ml dung dch H2SO4 37% ri un si 30 phut, ngui n nhit phong ri nh mc lai bng nc ct cho u 50ml, tin hanh cac bc tng t nh lp ng chun, n nh em o trn may so mau bc song = 690 - 722 nm. Ghi mt quang hoc thu quang cua mu th. 4. Tnh toan kt qua T kt qua o cua mu th, da vao th cua mu chun. Tnh toan kt qua theo cng thc sau:a [PO ] = V x10004 3

(mg/l)

Trong o: - a: Ham lng PO43- tm c theo th chun, tnh bng (mg) - V: Th tch mu nc th em th, tnh bng (ml).

Trang 33

Bai 7:

Xac nh ham lng Nitrit NO21. Nguyn tc pH t 2,0 n 2,5 ion nitric se tao s kt hp gia axit sunfanilic diazo vi -nathylamin cho mau hng. em so mau cua dung dch mu th vi thang mau cua mu chun se xac nh c ham lng nitric. Cac yu t can tr: Clo hoat ng co th cho mau phu, trong trng hp o phai cho thuc th -nathylamin trc sau o mi cho axit sunfuaric Ion Cu2+ phn huy mui diazo lam anh hng phep xac nh. nhay cua phng phap: 0,001mg/l 2. Dung cu , hoa cht * Dung cu: Cc thuy tch cac loai ng hut cac loai May so mau Thuc th Gris A:

* Hoa cht: Cn 0,5g axit sunfanilic (loai tinh khit) cho vao cc thuy tinh va hoa tan vao trong 150ml axit axetic 10%, khuy u va un nho la cho tan. yn ri em s dung. Thuc th Gris B: Cn 0,1g -nathylamin (loai tinh khit) cho vao cc thuy tinh, thm vao 20ml nc ct, khuy u va un cach thuy 15 phut cho tan ht ri thm axit axetic 10% cho u 150ml. Dung dch nay khng bao quan c lu, khi chuyn mau phai bo i va pha lai dung dch mi.Trang 34

-

Dung dch axit axetic 10%:

Hut 10 ml dung dch CH3COOH m c (99,5%) va pha vi 90 ml nc ct Dung dch nitric tiu chun: Cn chnh xac 0,1468g natri nitrit (NaNO2) cho vao cc thuy tinh va hoa tan bng nc ct. nh mc thanh 100ml. Ta c: 1ml dung dch nay co 1mg HNO2. Pha loang dung dch trn thu c dung dch: 1ml co 0,01mg HNO2 3. Cach tin hanh a. Lp ng chun: Chun b thang mu theo bang sau: Dung dch (ml) Dung dch co 0,01mg HNO/ml Nc ct Dung dch2

0 0

1 0,5

S th t cc thuy tinh 2 3 4 5 6 7 1,0 1,5 2,0 2,5 3,0 3,5

8 4,0

9 4, 5

1 1 0

1 1 0,0 05

nh mc thanh 50ml 1 1 1 1 1 1 0,0 1 1 0,0 15 1 0,0 2 1 0,0 25 1 0,0 3

1 1 0,0 35

1 1 0,0 4

1 1 0, 04 5

Gris A Dung

dch

Gris B Lng HNO2 trong cc mi thuy

tinh (mg) Nng

0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0,

HNO2 (mg/l) 9 thang mau n nh (t 5-10 phut) ri tin hanh o hp thu hay thu quang trn may so mau bc song = 520nm. Ghi mt quang hoc thu quang theo th t cua tng cc.Trang 35

Ve th biu din mi quan h gia hp thu hoc thu quang (truc tung) vi ham lng Fe tng s cua dung dch chun (truc hoanh). b. Xac nh ham lng NO2- trong mu nc th: Cho 50ml mu nc cn th vao trong cc thuy tinh 250ml (nu ham lng NO2- ln th phai pha loang), tin hanh cac bc tng t nh lp ng chun. n nh em o trn may so mau bc song = 520nm. Ghi mt quang hoc thu quang cua mu th. 4. Tnh toan kt qua T kt qua o cua mu th, da vao th cua mu chun. Tnh toan kt qua theo cng thc sau:a [NO ] = V x1000 2

(mg/l)

Trong o: - a: Ham lng HNO2 tm c theo th chun ,tnh bng (mg) - V: Th tch mu nc th em th nghim (ml).

Trang 36

Bai 8:

Xac nh ham lng Amoniac - Dung thuc th Netsle1. Nguyn tc Amoniac trong mi trng kim phan ng vi thuc th Netsle tao thanh phc cht mau vang n nu phu thuc ham lng amoniac co trong mu nc. em so mau cua mu th vi thang mau chun se bit c ham lng amoni co trong mu nc. Co th xac nh amoni trc tip trong mu nc hoc xac nh sau khi a ct mu nc. Khi mu nc b bn, co mau vang... thng c ct trc khi em xac nh Cac yu t can tr: - Ion sunfua can tr phep xac nh do tap cht mau vang. Kim tra: cho vao mu nc mt lng nho axit sunfuaric (c 5ml nc th cho 2ml axit sunfuaric 1:3), nu mu nc b uc la co sunfua. Trng hp nay, cho trong vao 100ml mu nc th 10 giot dung dch kem axetat 25%. Khi kt tua lng xung ly phn nc trong xac nh. 2. Dung cu, hoa cht * Dung cu: Cc thuy tch cac loai. ng hut cac loai. May so mau. Dung dch amoniac tiu chun:

* Hoa cht: Cn chnh xac 0,297g amoni clorua (NH4)Cl tinh khit cho vao cc thuy tinh va hoa tan trong mt t nc ct, sau o nh

Trang 37

mc thanh 1000ml, lc u. Ta c: 1ml dung dch nay co 0,1mg NH4+ Tin hanh pha loang dung dch trn co nng 0,01mg NH4+ trong 1ml. Thuc th Netsle: Hoa tan 6g HgCl2 vao trong 100ml nc ct nong (1) Hoa tan 50g KI vao trong 50ml nc ct (2) Nho t t dung dch (1) vao dung dch (2) n xut hin kt tua o, nhe va bn. Lc manh. Thm vao dung dch trn 200ml dung dch NaOH 6N (khuy u) ri thm nc ct n 500ml. Bao quan trong chai nu va bong ti. Dung dch mui Rynhet: Cn 30g mui kali-natri tactrat cho vao trong cc thuy tinh, hoa tan trong mt t nc ct, thm 5ml thuc th Netsle loai ht amoniac, sau o pha thanh 70ml. Loc va bao quan trong chai thuy tinh mau. 3. Cach tin hanh a. Lp ng chun: Chun b thang mu theo bang sau: Dung dch (ml) 0 Dung dch co 0,01mg NH+4/ml Nc ct Dung dch mui Rynhet Dung dch Netsle (giot) Lng NH4+ trong mi cc (mg) * 103Trang 38

1

S th t cc thuy tinh 2 3 4 5 6 7 0,5 1 2,5 5 10

8 25

9 50

0

0,1 0,25

nh mc thanh 50ml 0,5 2 0,5 2 0,5 2 0,5 2 0,5 2 0,5 2 0,5 2 0,5 2 0,5 2 0,5 2

0

1

2,5

5

10

25

50

10 0

25 0

50 0

Nng NH4

0

0,0 0,0

0,1

0,20

0,5

1,0 2,0 5,0

10,

(mg/l) 2 5 0 0 0 0 0 0 thang mau n nh (t 5-10 phut) ri tin hanh o hp thu hay thu quang trn may so mau bc song = 400 - 500nm. Ghi mt quang hoc thu quang theo th t cua tng cc. Ve th biu din mi quan h gia hp thu hoc thu quang (truc tung) vi ham lng Fe tng s cua dung dch chun (truc hoanh). b. Xac nh ham lng amoniac trong mu nc th: Cho 50ml mu nc cn th vao trong cc thuy tinh 250ml (nu ham lng amoniac ln th phai pha loang), tin hanh cac bc tng t nh lp ng chun. n nh em o trn may so mau bc song = 400 - 500nm. Ghi mt quang hoc thu quang cua mu th. * Khi mu nc b bn th tin hanh chng ct nh sau: Cho 250ml mu th vao bnh chng ct dung tch 500ml, thm 5g magie oxyt (MgO) ri lc u. Thm vao vai manh v thuy tinh ri lp vao ng sinh han. Tin hanh chng ct nhit 60-700C. Hng dch ct chay ra bng cc thuy tinh 250ml co cha 20ml dung dch axit sunfuaric 0,02N va 5 giot ch th natri alizarinsunfonat. Thu ly khoang 220ml dch ct va nh mc thanh 250ml. Dung dung dch NaOH 0,02N chun lng axit sunfuaric con d n khi ch th chuyn t mau vang sang hng th kt thuc. em dch ct nay xac nh amoniac. 4. Tnh toan kt qua T kt qua o cua mu th, da vao th cua mu chun. Tnh toan kt qua theo cng thc sau:a [NH ] = V x1000+ 4

(mg/l)

Trang 39

Trong o: - a: Ham lng NH4+ tm c theo th chun ,tnh bng (mg) - V: Th tch mu nc th em th nghim (ml). Bai 9:

Xac nh ham lng Nitrat NO3Thuc th axit fenoldisunfonic1. Nguyn tc Axit nitric giai phong t mui nitrat tac dung vi axit fenoldisunfonic cho axit nitrophenoldisunfonic. Amoniac tac dung vi nitrophenoldisunfonic cho phc mau vang. em so mau cua phc cht vi thang mau nitrat chun se bit c ham lng nitrat co trong mu nc. nhay cua phng phap: 0,01 mgNO3-/l 2. Thit b, dung cu, hoa cht * May moc, dung cu th nghim:-

May so mau co bc song = 400nm Bp in, bp cach thuy Cc thuy tinh chu nhit 250ml ng hut cac loai Thuc th axit fenoldisunfonic:

-

* Hoa cht: Cn 3g phenol tinh khit, nguyn cht hoa tan vao trong 20ml H2SO4 m c khuy u, ngui, sau 24 gi mi em s dung. Dung dch khng bn do o pha u dung tranh lang ph-

Dung dch NO3- tiu chun:

Cn chnh xac 1,609g KNO3 (tnh khit phn tch) , hoa tan vao trong mt t nc ct sau o nh mc thanh 1000ml. Ta co 1ml dung dch va chun b tng ng vi 1mg NO3- tnh chuynTrang 40

ra HNO3. Ly dung dch trn pha loang 10 ln ta c 1ml dung dch nay tng ng vi 0,1mg HNO3. Dung dch NO3- lam vic: Ly dung dch 1ml co 0,1mg pha loang co 1ml dung dch co 0,005mg HNO3 Amon hydroxit m c. 3. Cach tin hanh a. Lp ng chun: Chun b thang mu theo bang sau: Dung dch (ml) Dung dch HNO3 pha loang: 0,005mg/ml Nc ct Thuc th axit fenol disunfonic Amon hydroxit m c Nc ct Lng HNO3 trong mi cc thuy tinh (mg) * 10-3 Nng HNO3 (mg/l) 0 0, 0, 0, 0,4 0, 0, 1,0 0 5 10 15 20 30 40 50 S th t cc thuy tinh 0 1 2 3 4 5 6 7 8 9 12, 0 1 2 3 4 6 8 10 15 5 nh mc thanh 50ml, sy kh trn bp cach thuy va ngui n nhit phong 1 5 1 5 1 5 1 5 1 5 1 5 1 5 1 5 1 5 1 5

ngui n nhit phong va nh mc thanh 50ml. 62, 5 1,2 75 1,

1 2 3 6 8 5 5 thang mau n nh (t 5-10 phut) ri tin hanh o

hp thu hay thu quang trn may so mau bc song = 400nm. Ghi mt quang hoc thu quang theo th t cua tng cc.

Trang 41

Ve th biu din mi quan h gia hp thu hoc thu quang (truc tung) vi ham lng NO3- cua dung dch chun (truc hoanh). b. Xac nh ham lng NO3- trong mu nc th: Cho 50ml mu nc cn th vao trong cc thuy tinh chu nhit, un cach thuy cho n kh can, ngui. Cho 1ml thuc th axit fenoldisunfonic vao rai u, thm nc ct (khoang 10ml) va 5ml amon hydroxit m c vao dung ua thuy tinh khuy u (nu xut hin mau vang chng to co ion NO3-) Chuyn tt ca dung dch vao bnh nh mc 50ml va trang cc thuy tinh nhiu ln bng nc ct cho nc trang vao bnh nh mc va nh mc thanh 50ml. em o trn may so mau bc song = 400nm. Ghi mt quang hoc thu quang cua mu th. T mt quang hoc thu quang cua mu nc th va o c, da vao th biu din mi quan h gia mt quang hoc thu quang vi nng NO 3- cua mu chun, ta se tnh c ham lng NO3- co trong mu nc th 4. Tnh toan kt qua T kt qua o cua mu th, da vao th cua mu chun. Tnh toan kt qua theo cng thc sau:a [NO ] = V x1000 3

(mg/l)

Trong o: - a: Ham lng NO3- tm c theo th chun, tnh bng (mg) - V: Th tch mu nc em th, tnh bng (ml)

Trang 42

Bai 10:

Xac nh ham lng St tng s(DUNG THUC TH THIOXYANUA) 1. Nguyn tc Da trn tac dung cua st (III) trong mi trng axit manh vi thuc th thioxyanua se tao ra hp cht phc mau o cua st thioxynat. em so mau cua phc cht vi thang mau Fe (III) chun se bit c ham lng Fe tng s co trong mu nc. nhay cua phng phap: 0,05 mg Fe(III) /l 2. Thit b, dung cu, hoa cht * May moc, dung cu th nghim:-

May so mau co bc song = 500nm Cc thuy tinh 250ml ng hut cac loai Thuc th amoni thioxyanua (NH4)SCN hoc kali thioxyanua KSCN

-

* Hoa cht:

Hoa tan 50 g amoni thioxyanua (NH4)SCN hoc kali thioxyanua KSCN vao trong 50 ml nc ct.-

Dung dch HCl 1,12 g/cm3

Thm 100 ml axit clohydric co khi lng ring 1,19 g/cm 3 khng cha st vao 65 ml nc ct. -

Amoni pesunfat tinh th. Dung dch Fe (III) tiu chun:Trang 43

Cn chnh xac 0,8836g st-amoni (tnh khit phn tch), hoa tan vao trong mt t nc ct, thm 2 ml HCl m c sau o nh mc thanh 1000ml. Ta co 1ml dung dch va chun b tng ng vi 0,1mg Fe (III). Chun b dung dch lam vic trong ngay bng cach pha loang dung dch chnh giam i 10 ln. Ta co 1 ml dung dch co 0,01 mg st (III) 3. Cach tin hanh a. Lp ng chun: Chun b thang mu theo bang sau: Dung dch (ml) Dung dch 0 co 0 1 0,5 S th t cc thuy tinh 2 3 4 5 6 7 1,0 2,0 3,0 4,0 5,0 6,0 8 7,0 9 8,0

0,01mg Fe(III)/ml Nc ct Dung dch HCl 1,12g/cm3 Amoni pesunfat

nh mc thanh 50ml 1 Ha t nh o 1 Ha t nho 1 Ha t 1 1 Ha t 1 1 Ha t 1 1 Ha t 1 1 Ha t 1 1 Ha t 1 1 Ha t 1 1 Ha t 1

nho nho nho nho nho nho nho nho

Dung (NH4)SCN KSCN Lng

dch hoc Fe (III) 0 5 10 20 30 40 50 60 70 80 1 1

trong mi cc thuy tinh (mg) * 103 Nng Fe (III)

0 0,1 0,2 0,4 0,6 0,8 1,0 1,2 1,4 1,6 (mg/l) thang mau n nh (t 5-10 phut) ri tin hanh o hp thu hay thu quang trn may so mau bc song =Trang 44

500nm. Ghi mt quang hoc thu quang theo th t cua tng cc. Ve th biu din mi quan h gia hp thu hoc thu quang (truc tung) vi ham lng Fe tng s cua dung dch chun (truc hoanh). b. Xac nh ham lng Fe tng s trong mu nc th: Cho 50ml mu nc cn th vao trong cc thuy tinh 250ml (nu ham lng Fe ln th phai pha loang). Thm 1ml dung dch HCl 1,12 g/cm3, mt hat nho amoni pesunfat tinh th; lc u va thm tip 1ml dung dch amoni thioxyanua (NH4)SCN hoc kali thioxyanua KSCN. Sau khi lc, n nh em o trn may so mau bc song = 500nm. Ghi mt quang hoc thu quang cua mu th. 4. Tnh toan kt qua T kt qua o cua mu th, da vao th cua mu chun. Tnh toan kt qua theo cng thc sau:

[ Fe TS ] = aV

x1000

(mg/l)

Trong o: - a: Ham lng Fe tng s tm c theo th chun, tnh bng (mg) - V: Th tch mu nc em th, tnh bng (ml).

Trang 45

Bai 11:

Xac nh mt s kim loai nng thng gpA. Xac nh ham lng ng (Cu2+)1. Nguyn tc Da trn tac dung cua ion ng hoa tr hai vi natri dietylthiocacbanat cho mau o gach. em so mau vi day chun se bit c ham lng ng co trong mu chun. 2. Dung cu, hoa cht * Dung cu: Bp cach thuy Cc thuy tinh cac loai ng hut cac loai May so mau Nc ct hai ln khng cha ng Dung dch natri dietylthiocacbanat 0,1%:

* Hoa cht:

Cn 1g natri dietylcacbanat (loai tinh khit) cho vao cc thuy tinh va hoa tan trong mt t nc ct. Loc va thm nc ct n 1lt. Bao quan dung dch trong chai thuy tinh mau va bong ti. Dung dch amon hydroxyt 1:4: Dung nc ct pha loang dung dch amon hydroxyt 25% vi ty l 1:4. Dung dch kali-natri tactrat (mui Rynhet) Cn 50g Ka-Na tactrat (K-NaC4H4O6.4H2O) va hoa tan vao trong 50ml nc ct. Dung dch ng tiu chun:Trang 46

Cn chnh xac 0,393g ng sunfat (CuSO4.5H2O) cho vao cc thuy tinh, hoa tan trong mt t nc ct co pha 1ml axit sunfuaric 1:5 va nh mc thanh 1 lt. Ta c 1ml dung dch nay cha 0,1mg Cu2+ Pha loang dung dch trn co ham lng 0,01mg Cu+2/1ml Dung dch amoni pesunfat 5%: Cn 5g amoni pesunfat (NH4) S2O8 cho vao cc thuy tinh va hoa tan vao trong 95ml nc ct. Dung dch h tinh bt 0,25%: Cn 0,25g tinh bt hoa tan vao trong 100ml nc ct lanh sau o un si, ngui la loc s dung. 3. Cach tin hanh a. Lp ng chun: Chun b thang mu theo bang sau: Dung dch (ml) Dung dch co 0,01mg Cu2+ /1ml Nc ct Dung dch Raynhet Dung dch 0 0 S th t cc thuy tinh 1 2 3 4 5 0,1 0,2 0,5 1,0 2,0 6 3,0

nh mc thanh 50ml mui amon 1 5 1 5 1 5 1 5 0,00 1 0,00 2 1 5 1 5 0,00 2 0,04 1 5 1 5 0,00 5 0,10 1 5 1 5 1 5 1 5 1 5 1 5

hydroxyt 4:1 Dung dch h tinh bt 0,25% Dung dch dietylcacbanat Lng Cu2+ natri trong

mi cc thuy tinh (mg) Nng Cu2+ (mg/l)

0

0,01

0,02

0,03

0

0,20

0,40

0,60

Trang 47

thang mau n nh (t 5-10 phut) ri tin hanh o hp thu hay thu quang trn may so mau bc song = 430nm. Ghi mt quang hoc thu quang theo th t cua tng cc. Ve th biu din mi quan h gia hp thu hoc thu quang (truc tung) vi ham lng Cu2+ cua dung dch chun (truc hoanh). b. Xac nh ham lng Cu2+ trong mu nc th: Cho 50ml mu nc cn th vao trong cc thuy tinh 250ml (nu ham lng Cu2+ ln th phai pha loang va cha axit hoa th phai thm t 1-2 giot axit clohydric 1:1) tin hanh cac bc tng t nh lp ng chun, n nh em o trn may so mau bc song = 430nm. Ghi mt quang hoc thu quang cua mu th. 4. Tnh toan kt qua T kt qua o cua mu th, da vao th cua mu chun. Tnh toan kt qua theo cng thc sau:a [Cu ] = V x10002+

(mg/l)

Trong o: - a: Ham lng Cu2+ tm c theo th chun, tnh bng (mg) - V: Th tch mu nc th em th, tnh bng (ml). B. Xac nh ham lng kem 1. Nguyn tc Trong mi trng axit kem se tac dung vi dithizon tao phc mau o, dung cabon tetraclorua chit hp cht nay va em so mau vi day chun. 2. Dung cu, hoa cht * Dung cu:Trang 48

-

Bp cach thuy Phu chit dung tch 100ml ng hut cac loai May so mau Dung dch kem tiu chun:

* Hoa cht: Cn chnh xac 0,1g kim loai kem tinh khit, cho vao cc thuy tinh va hoa tan bng 2ml axit clohydric 1:1, ch cho tan ht va chuyn vao trong bnh nh mc 1lit va thm nc ct n vach. Trong 1ml dung dch nay co cha 0,1mg Zn2+. Pha loang dung dch trn c 1ml co cha 0,0005mg Zn2+. Dung dch natri axetat 2N: Cn 68g natri axetat (CH3COONa.3H2O) cho vao cc thuy tinh va hoa tan trong mt t nc ct va thm nc ct n 250ml. Dung dch dithizon 0,01% va 0,002%: Cn 0,05g dithizon cho vao cc thuy tinh va hoa tan trong mt t cacbon tetraclorua chuyn vao bnh nh mc 500ml va thm cacbon tetraclorua n vach, lc u va thu c dung dch 0,01%. T dung dch nay chun b cac dung dch co nng 0,002% va 0,001%. Dung dch natri thiosunfat 20%: Cn 20g natri thiosunfat (Na2S2O5.5H2O) cho vao cc thuy tinh va hoa tan trong 80ml nc ct. 3. Cach tin hanh a. Lp ng chun: Chun b thang mu theo bang sau: gm 7 phu chit co dung tch 100mlTrang 49

Dung dch Dung (ml) dch 0 co 0

S th t phu chit 1 2 3 4 5 0,5 1,0 2,0 3,0 4,0

6 5,0

0,0005mg Zn2+/1ml Nc ct Dung dch m axetat Dung dch natri

nh mc thanh 50ml 5 1 4 5 1 4 5 1 4 5 1 4 5 1 4 5 1 4 5 1 4

thiosunfat 20% Dung dch dithizon 0,002% Lng Zn2+ trong

mi cc thuy tinh

0

0,25

0,5

1

1,5

2

2,5

(mg) *103 Nng Zn2+ (mg/l) 0 0,005 0,01 0,02 0,03 0,04 0,05 Lc manh phu chit sau o thng ng t 5-10 phut cho phn lp, rot phn cacbon tetraclorua di ay phu chit em o hp thu hay thu quang trn may so mau bc song = 530nm. Ghi mt quang hoc thu quang theo th t cua tng phu chit. Ve th biu din mi quan h gia hp thu hoc thu quang (truc tung) vi ham lng Zn 2+ cua dung dch chun (truc hoanh). b. Xac nh ham lng Zn2+ trong mu nc th: Cho 50ml mu nc cn th vao trong phu chit thuy tinh 100ml (nu ham lng Zn2+ ln th phai pha loang va cha axit hoa th phai thm t 1-2 giot axit clohydric 1:1) tin hanh cac bc tng t nh lp ng chun, n nh em o trn may so mau bc song = 530nm. Ghi mt quang hoc thu quang cua mu th.

Trang 50

4. Tnh toan kt qua T kt qua o cua mu th, da vao th cua mu chun. Tnh toan kt qua theo cng thc sau:

2+ a Z n = V x1 0 0 0(mg/l) Trong o: - a: Ham lng Zn2+ tm c theo th chun, tnh bng (mg) - V: Th tch mu nc th em th, tnh bng (ml). C. Xac nh ham lng Cadimi (Cd2+) 1. Nguyn tc Cho ion cadimi tac dung vi thuc th difenylthiocacbazon, chit phc cht tao thanh bng dung mi thch hp loai cac ion can tr va so mau vi day chun t o xac nh c ham lng cadimi co trong mu nc. 2. Dung cu, hoa cht * Dung cu: Phu chit dung tch 100ml ng hut cac loai. Cc thuy tinh cac loai. May so mau Dung dch cadimi tiu chun:

* Hoa cht: Dung dch gc: Cn chnh xac 0,1g cadimi kim loai tinh khit, hoa tan vao trong 20ml co cha 5ml axit clohydric ch cho tan ht ri chuyn ht vao bnh nh mc 1000ml va thm nc ct n vach. Ta c 1ml dung dch nay co cha 0,1mg CdTrang 51

Dung dch lam vic: Hut 10ml dung dch gc va 10ml HCl m c cho va bnh nh mc 1000ml va thm nc n vach. Ta c 1ml dung dch nay co cha 0,001mg Cd2+. Dung dch kali-natri tactrat 25%: Cn 25g kali-natri tactrat tinh khit (K-Na.C4H4O6.2H2O) cho vao cc va hoa tan vao trong 75ml nc ct. Bao quan trong bnh nha. Dung dch dithizon (1): Cn 0,1g difenylthiocacbazon cho vao cc va hoa tan vao trong 100ml cloruafom, chuyn toan b dung dch vao bnh nh mc 1000ml va thm nc n vach. Dung dch dithizon (2): Dung dch NaOH 20%: Bng cach pha loang dung dch dithizon (1) 10 ln. Cn 20g NaOH tinh khit cho cc thuy tinh va hoa tan vi 80ml nc ct (cha trong bnh nha). Dung dch NaOH va KCN: Dung dch (1): Cn 400g NaOH va 10g KCN cho vao cc thuy tinh va hoa tan vao trong 1000ml nc ct. Dung dch (2) Cn 400g NaOH va 0,5g KCN cho vao cc thuy tinh va hoa tan vao trong 1000ml nc ct. Dung dch (1) va (2) bao quan trong bnh nha, dung dch bn trong 1 - 2 thang Dung dch clohydrat hydroxylamin 20% Cn 20g clohydrat hydroxylamin cho vao cc thuy tinh va hoa tan vao trong 80ml nc ct. Dung dch axit tactricTrang 52

Cn 20g ax tacric tinh khit cho vao cc thuy tinh va hoa tan trong 1000ml nc ct Cloruaform tinh khit. 3. Cach tin hanh a. Lp ng chun: Chun b thang mu theo bang sau: gm 10 phu chit dung tch 100ml Dung dch (ml) Dung dch chun 1ml cha 0,001mg Cd2+. Nc ct Dung dch Na-K tactrat 25% Dung dch NaOH -KCN (1) Dung dch clohydrat hydroxylamin 20% Dung dch 0 0 1 0, 5 S th t phu chit 2 3 4 5 6 7 1,0 2,0 4,0 6,0 8,0 8 9 14, 0

10 12 ,0 ,0

nh mc thanh 50ml 1 5 1 5 1 5 1 5 1 5 1 5 1 5 1 5 1 5 1 5

1

1

1

1

1

1

1

1

1

1

15 15 15 15 15 15 15 15 15 15 dithizon (2) Lc u 2 phut va yn t 5-10 phut cho phn lp, tach ly lp dung mi hu c pha di, ri thm Axit tactric 20g/l 25 25 25 25 25 25 25 25 2+ Lng Cd co trong mi cc (mg) * 103 Nng Cd2+ 0 0,5 0,0 1 0,0 2 4 6 0,1 8 0,1 10 0, 25 12 0,2 25 14 0,2

(mg/l) 1 2 4 8 2 6 2 4 8 Chit ly phn lp hu c pha di ri tin hanh o hp thu hay thu quang trn may so mau bc song = 518nm. Ghi mt quang hoc thu quang theo th t cua tng phu chit.Trang 53

0

0,0 0,0

Ve th biu din mi quan h gia hp thu hoc thu quang (truc tung) vi ham lng Cd2+ cua dung dch chun (truc hoanh). b. Xac nh ham lng Cd2+ trong mu nc th: Cho 50ml mu nc cn th vao trong phu chit thuy tinh dung tch 250ml (nu ham lng Cd2+ ln th phai pha loang), tin hanh cac bc tng t nh lp ng chun, n nh em o trn may so mau bc song = 510nm. Ghi mt quang hoc thu quang cua mu th. i vi mu khng cn phn huy: Ly chnh xac 50ml mu nc th a dc axit hoa cho vao phu chit, cho tip 20ml HNO3 1:4, 50ml dung dch kh citrat-cyanua va10ml dung dithizon lam vic. Lc u va manh 2 phut, yn t 5 - 10 phut cho phn phn lp. Chit ly phn dung mi di em o mau bc song song = 510nm. Ghi mt quang hay thu quang cua mu th. 4. Tnh toan kt qua T kt qua o cua mu th, da vao th cua mu chun. Tnh toan kt qua theo cng thc sau:a [Cd ] = V x10002+

(mg/l)

Trong o: - a: Ham lng Cd2+ tm c theo th chun, tnh bng (mg/l) - V: Th tch mu nc th em th, tnh bng (ml). D. Xac nh ham lng ch (Pb2+) 1. Nguyn tc Trong mi trng kim ion Pb2+ tao phc vi thuc th dithizon (diphenylthiocacbazon) thanh ch dithizonat kho tan trong nc nhng d tan trong nhiu dung mi hu c nh CCl4 hocTrang 54

CHCl3. Trong dung mi hu c ch dithizonat co mau o em so mau bc song = 520nm so va sanh vi mau cua day chun ta xac nh c ham lng ch co trong mu nc. Trong mu nc co cha cac cht hu c ang k se anh hng n kt qua phn tch, cn phai loai bo. 2. Dung cu, hoa cht * Dung cu: Phu chit dung tch 100ml ng hut cac loai May so mau Dung dch dithizon gc:

* Hoa cht: Cn 50mg dithizon va hoa tan vao trong 100ml dung dch CCl4 trong phu chit dung tch 500ml, thm vao 200ml nc ct va t 5 - 10ml dung dch NH4OH m c. y kn nut va lc ky trong 2 phut. Dithizon a chuyn sang pha nc, yn cho phn lp va thao bo lp dung mi hu c, thm vao phu chit 20ml CCl4 lc u, yn cho phn lp va thao bo tip lp dung mi hu c. Cn thn thm vao phu chit 200ml dung dch CCl4 va HCl loang cho n khi pha nc co mi trng axit ro (th bng giy o pH). y kn nut va lc u hn hp chuyn toan b lng dithizon t pha nc sang pha dung mi hu c, yn cho phn lp va chuyn toan b lng dung mi hu c sang mt phu chit khac (bo phn nc ni trn) va ra no 3 ln bng nc ct.. Chuyn toan b dung dch dithizon a c lam sach vao bnh thuy tinh nu va phu ln trn b mt dung dch o mt lp dung dch HCl 0,5% co cha NH 2NH2.H2SO4 0,5%. dung dch trong bong ti va mat. Dung dch bn trong vai thang. Dung dch dithizon lam vic:Trang 55

Ly 1 th tch dung dch dithizon gc trn trn vi 1 th tch dung dch CCl4 sach va cha trong chai thuy tinh mau nu. Dung dch bn trong 1 thang. Dung dch ch chun: Cn chnh xac 100mg Pb kim loai tinh khit cho vao cc thuy tinh va thm vao 4ml dung dch HNO3 1:1, un nong ch tan hoan toan, ngui va chuyn toan b vao bnh nh mc 1lt va thm nc ct n vach. Ta co 1ml dung dch co cha 0,1mg Pb2+. Pha loang dung dch trn co 1ml dung dch cha 0,002mg Pb2+. Hoc: Cn chnh xac 0,1598g Pb(NO3) tinh khit cho vao cc thuy tinh, hoa tan trong 200ml nc ct, cho vao 10ml HNO 3 m c chuyn dung dch vao bnh nh mc 1000ml va thm nc n vach. Ta co 1ml dung dch co cha 0,1mg Pb2+ Pha loang dung dch trn co 1ml dung dch cha 0,002mg Pb2+.-

Dung dch axit nitric (HNO3) 1:4

Hut 1 th tch axit nitric m c pha loang vi 4 th tch nc ct.-

Dung dch amon hidroxyt (NH4OH) 1:9

Hut 1 th tch dung dch NH4OH m c va pha loang vi 9 th tch nc ct. Dung dch kh citrat cyanua: Cn 100g (NH4)2HC6H5O7, 5g Na2SO3, 2,5g NH2OH.HCl va 10g KCN cho vao cc thuy tinh, hoa tan vao trong 250ml nc ct. Trn dung dch trn vi 500ml NH4OH m c. 3. Cach tin hanh a. Lp ng chun:Trang 56

Chun b thang mu theo bang sau: gm 9 phu chit co dung tch 250ml nh sau:

Trang 57

Dung dch Dung (ml) dch 0 co 0

0,002mg Pb2+/1ml Nc ct Dung dch HNO3 m c Dung dch HNO3 1:4 Dung dch citratcyanua Dung dch dithizon

S th t cua phu chit 1 2 3 4 5 6 7 10, 15, 20, 30, 40, 2,5 5,0 0 0 0 0 0 nh mc thanh 50ml 1 20 50 1 20 50 1 20 50 10 1 20 50 10 1 20 50 10 1 20 50 10 1 20 50 10

8 50, 0 1 20 50 10

1 20 50

10 10 10 lam vic Lc u va manh 2 phut, yn Lng Pb2+ co trong 0 5 10 mi cc (mg) * 103 Nng Pb2+ (mg/l) 0 0,1 0,2

t 5-10 phut cho phn lp 20 0,4 30 0,6 40 0,8 60 1,2 80 1,6 100 2,0

Chit ly phn lp hu c pha di ri tin hanh o hp thu hay thu quang trn may so mau bc song = 510nm. Ghi mt quang hoc thu quang theo th t cua tng phu chit. Ve th biu din mi quan h gia hp thu hoc thu quang (truc tung) vi ham lng Pb 2+ cua dung dch chun (truc hoanh). b. Xac nh ham lng Pb2+ trong mu nc th: Cho 50ml mu nc cn th vao trong phu chit thuy tinh dung tch 250ml (nu ham lng Pb2+ ln th phai pha loang), tin hanh cac bc tng t nh lp ng chun, n nh em o trn may so mau bc song = 510nm. Ghi mt quang hoc thu quang cua mu th. i vi mu khng cn phn huy:Trang 58

Ly chnh xac 50ml mu nc th a dc axit hoa cho vao phu chit, cho tip 20ml HNO3 1 : 4, 50ml dung dch kh citrat-cyanua va10ml dung dithizon lam vic. Lc u va manh 2 phut, yn t 5 -10 phut cho phn phn lp. Chit ly phn dung mi di em o mau bc song song = 510nm. Ghi mt quang hay thu quang cua mu th. 4. Tnh toan kt qua T kt qua o cua mu th, da vao th cua mu chun. Tnh toan kt qua theo cng thc sau:a [Pb ] = V x10002+

(mg/l)

Trong o: - a: Ham lng Pb2+ tm c theo th chun, tnh bng (mg) - V: Th tch mu nc th em th, tnh bng (ml). E. Xac nh ham lng Mangan 1. Nguyn tc Da trn vic oxy hoa hp cht cua mangan n hoa tr MnO4- trong mi trng axit. Dung amoni pesunfat (NH4S2O8) hoc mui kali cua no co bac lam xuc tac. Sau phan ng dung dch co mau hng. em so mau vi day chun t o xac nh c ham lng cua mangan co trong mu nc. 2. Dung cu, hoa cht * Dung cu: Bp cach thuy Cc thuy tinh cac loai ng hut cac loai May so mau Dung dch kali pemanganat tiu chun:Trang 59

* Hoa cht:

Hut 9ml dung dch kali pemanganat 0,01N, cho vao bnh nh mc 1000ml, thm nc ct n vach. Ta c 1ml dung dch nay cha 0,01mg Mn2+ Dung dch thuc th c bit: Cn 75g thuy ngn sunfat (HgSO4) cho vao cc thuy tinh, thm vao 400ml axit nitric (HNO3) m c va 200ml nc ct, khuy cho tan ri thm 200ml axit octophotphoric 85% va 0,0035g bac nitrat. Khuy cho tan ri lam ngui dung dch va thm nc ct n 1lit. 3. Cach tin hanh a. Lp ng chun: Chun b thang mu theo bang sau: Dung dch (ml) Dung dch co 0,01mg Mn2+/1ml Nc ct Dung dch thuc th 0 0 S th t cc thuy tinh 1 2 3 4 5 6 7 8 0, 1 2 3 4 5 6 8 5 nh mc thanh 50ml 9 10

5 5 5 5 5 5 5 5 5 5 c bit un si c c mu n th tch khoang 20ml, ngui n nhit phong Mui amoni pesunfat

1 1 1 1 1 1 1 1 1 (gam) un si khoang 5 phut, ngui n nhit phong Nc ct nh mc thanh 50ml 2+ Lng Mn trong mi 0 5 10 20 30 40 50 60 80 cc(mg) * 103 Nng Mn2+ (mg/l) * 0, 0, 0, 1, 1, 0 0,6 0,8 1,2 103 1 2 4 0 6

1

10 0 2,0

thang mau n nh (t 5-10 phut) ri tin hanh o hp thu hay thu quang trn may so mau bc song =

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525 - 530nm. Ghi mt quang hoc thu quang theo th t cua tng cc. Ve th biu din mi quan h gia hp thu hoc thu quang (truc tung) vi ham lng Mn2+ cua dung dch chun (truc hoanh). b. Xac nh ham lng Mn2+ trong mu nc th: Cho 50ml mu nc cn th vao trong cc thuy tinh 250ml (nu ham lng Mn2+ ln th phai pha loang), tin hanh cac bc tng t nh lp ng chun, n nh em o trn may so mau bc song = 525 - 530nm. Ghi mt quang hoc thu quang cua mu th. 4. Tnh toan kt qua T kt qua o cua mu th, da vao th cua mu chun. Tnh toan kt qua theo cng thc sau:a [Mn ] = V x10002+

(mg/l)

Trong o: - a: Ham lng Mn2+ tm c theo th chun, tnh bng (mg) - V: Th tch mu nc th em th, tnh bng (ml).

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Bai 12:

Xac nh cac ch tiu sinh hoc: E.Coli, ColiformA. E. Coli B. Coliform

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