XÁC ĐỊNH ASEN TRONG CHÈ XANH Ở THÁI NGUYÊN BẰNG PHƯƠNG PHÁP PHỔ HẤP THỤ NGUYÊN TỬ9843LV2011_SP_DangQuocTrung

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Thi Nguyn l khu vc c nhiu m khong sn ang khai thc, cckhu cng nghip ng thi cng l vng sn xut ch c sn. t, nc sn xut nng nghip khu vc khai thc khong sn, cng nghip thng b nhim trong c kim loi nng. Ch c th b nhim mt s kim loi nng t t, nc, v khng kh. V vy, cn phi quan tm nghin cu v kim tra khng ch cc cht c hi, c bit l cc kim loi nng nh hng trc tip n sc kho con ngi.

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Sha bi Trung tm Hc liu i hc Thi Nguyn http://www.lrc-tnu.edu.vn I HC THI NGUYN TRNG I HC S PHM

NG QUC TRUNG XC NH ASEN TRONG CH XANH THI NGUYN BNG PHNG PHP PH HP TH NGUYN T LUN VN THC S KHOA HC HA HC Thi Nguyn Nm 2011 Sha bi Trung tm Hc liu i hc Thi Nguyn http://www.lrc-tnu.edu.vn I HC THI NGUYN TRNG I HC S PHM

NG QUC TRUNG XC NH ASEN TRONG CH XANH THI NGUYN BNG PHNG PHP PH HP TH NGUYN T Chuyn ngnh: Ha phn tch M s: 60.44.29 LUN VN THC S KHOA HC HA HC NGI HNG DN KHOA HC PGS. TSNGUYN NG C Thi Nguyn Nm 2011 Sha bi Trung tm Hc liu i hc Thi Nguyn http://www.lrc-tnu.edu.vn Li cam oan Tixincamoanylcngtrnhnghincu caring ti. Cc sliu,kt qunutronglun vn l trung thc. Nhng kt lun ca lun vn cha cng b trong bt k cng trnh no khc. TC GI LUN VN

Sha bi Trung tm Hc liu i hc Thi Nguyn http://www.lrc-tnu.edu.vn LI CM N EmxinchnthnhcmnthygioPGS.TSNguynngc trc tip giao cho em ti, tn tnh hng dn v to mi iu kin cho em honthnhlunvn.EmxinchnthnhcmnthygioPGS.TSNguyn Xun Trung, PGS.TS Nguyn Duy Lng tham gia ng gp gip trong qu trnh hon thnh bn lun vn. Em xin chn thnh cm n cc thy c gio Khoa Ho hc, Khoa Sau i hc HSPTN, cc thy c gio, cc cn b nhn vin phng th nghim Khoa HohcHKHHTN,PhngHaphn tchihc KHTN ihcQucgiaHNi,Banlnho,cccchanh(ch)khoaXt nghim Trung tm y t dphngtnh ThiNguyn gip toiukin cho em hon thnh bn lun vn ny. Thi Nguyn, ngy 10 thng 8 nm 2011 Hc vin Sha bi Trung tm Hc liu i hc Thi Nguyn http://www.lrc-tnu.edu.vn 1 MC LC M U ............................................................................................................................ 1 Chng 1 ............................................................................................................................ 2 TNG QUAN .................................................................................................................... 2 1.1. Gii thiu chung v cy ch ................................................................... 2 1.1.1. c im v thnh phn ................................................................... 2 1.1.2. Cng dng ca cy ch..................................................................... 2 1.2. Gii thiu v nguyn t Asen ................................................................. 3 1.2.1.V tr, cu hnh electron v trng thi t nhin ................................. 3 1.2.2.Tnh cht vt l, tnh cht ho hc ..................................................... 4 1.2.3. Hp cht ca asen v tnh cht ca chng ....................................... 6 1.2.4. Cc phn ng c trng ca hp cht asen ...................................... 8 1.3. S nhin Asen v c tnh ca n ....................................................... 9 1.3.1. Ngun gc s nhim Asen ............................................................ 9 1.3.2. nhim asen trn th gii ............................................................. 10 1.3.3. nhim asen Vit Nam .............................................................. 12 1.3.4. c tnh ca asen ........................................................................... 13 1.4. Phng php in phn ........................................................................ 15 1.5. Cc phng php xc nh Asen .......................................................... 15 1.5.1. Cc phng php khi lng ......................................................... 16 1.5.2. Cc phng php phn tch th tch ............................................... 18 1.5.3.Cc phng php o quang ............................................................. 19 1.5.4. Cc phng php in ho ............................................................. 20 1.5.5. Phng php phn tch quang ph ................................................. 21 1.6. Phng php x l mu phn tch xc nh Asen ................................ 24 1.6.1. Phng php x l t (bng axit c oxi ho mnh) .................... 24 Sha bi Trung tm Hc liu i hc Thi Nguyn http://www.lrc-tnu.edu.vn 2 1.6.2. Phng php x l kh .................................................................. 25 Chng 2 .......................................................................................................................... 26 I TNG V PHNG PHP NGHIN CU....................................... 26 2.1. i tng v mc tiu nghin cu ....................................................... 26 2.1.1. i tng v mc tiu .................................................................... 26 2.1.2. Cc ni dung nghin cu ................................................................ 26 2.2. Gii thiu v phng php ph hp th nguyn t .............................. 27 2.2.1. Nguyn tc ca phng php AAS ................................................ 27 2.2.2. H trang b ca php o AAS ........................................................ 28 2.3. Gii thiu v phng php x l t mu ........................................... 31 2.3.1. Nguyn tc v bn cht .................................................................. 31 2.3.2. C ch phn hu ............................................................................. 32 2.4. Ha cht v dng c ............................................................................. 32 2.4.1: Ha cht.......................................................................................... 32 2.4.2: Dng c .......................................................................................... 33 Chng 3 .......................................................................................................................... 34 KT QU V THO LUN ................................................................................... 34 3.1. Kho st cc iu kin o ph GF-AAS ca Asen ............................... 34 3.1.1. Kho st chn vch o ................................................................... 34 3.1.2. Kho st chn khe o ca my ph hp th nguyn t.................. 35 3.1.3. Kho st cng dng n catot rng ......................................... 35 3.2. Kho st cc iu kin nguyn t ho mu .......................................... 36 3.2.1. Nhit sy kh mu ..................................................................... 37 3.2.2. Kho st nhit tro ho luyn mu .............................................. 37 3.2.3. Kho st nhit nguyn t ho mu ............................................ 38 3.2.4.Cc iu kin khc .......................................................................... 39 3.3.Kho st cc yu t nh hng n php o GF - AAS ........................ 39 Sha bi Trung tm Hc liu i hc Thi Nguyn http://www.lrc-tnu.edu.vn 3 3.3.1.Kho st nh hng ca nng axit v loi axit .......................... 39 3.3.2 Kho st nh hng ca cht ci bin nn (cht ci bin ha hc)40 3.3.3. Kho st thnh phn mu ............................................................... 42 3.3.4. Kho st nh hng ca cc cation v anion ................................. 43 3.5 Phng php ng chun i vi php o GF AAS ........................ 48 3.5.1 Kho st khong tuyn tnh ............................................................. 48 3.7.2. Xy dng ng chun .................................................................. 49 3.4.2. nh gi sai s, gii hn pht hin, gii hn nh lng v lp li ca php o .......................................................................................... 52 3.4.3. Tm tt cc iu kin o ph ca Asen ......................................... 54 3.5. Xc nh Asen trong ch xanh .............................................................. 54 3.5.1 a im thi gian ly mu v k hiu mu ................................... 54 3.5.2. Chun b mu phn tch .................................................................. 56 3.5.3. Kt qu phn tch cc mu ch xanh .............................................. 56 3.5.4: Kim tra qu trnh s l mu ......................................................... 57 KT LUN ..................................................................................................................... 61 TI LIU THAM KH0 ........................................................................................... 62 PH LC ......................................................................................................................... 65 Sha bi Trung tm Hc liu i hc Thi Nguyn http://www.lrc-tnu.edu.vn 4 DANH MC CC K HIU CH VIT TT AAS: Atomic Absorption Spectrometry ( Ph hp th nguyn t) Abs: Absorbance ( hp th) AES: Atomic Emission Spectrometry (Ph pht x nguyn t) ETA-AAS: Electro Thermal Atomization Atomic Absortion spectrometry(Ph hp th nguyn t khng ngn la) F-AAS: Flame- Atomic Absorption Spectrometry(Ph hp th nguyn t ngn la) GC-MS: Gas Chromatography Mas Spectroscopy(Sc k kh ghp khi ph)GF-AAS: Graphite Furnace- Atomic Absorption Spectrometry(Ph hp th nguyn t khng ngn la) HCL:Hollow Cathode Lamp (n catot rng) HG-AAS: Hyrie Generation- Atomic Absorption Spectrometry (Ph hp th nguyn t k thut Hidrua ha) HPLC: High Performance Liquid Chromatography(Sc k lng hiu nng cao) ICP-AES: Inductively Coupled Plasma Mass- Atomic Emission Spectrometry (Ph pht x nguyn t dng nng lng plasma cao tn cm ng) ICP-MS : Inductively Coupled Plasma Mass Spectrometry (Ph khi lng dng nng lng Plasma cao tn cm ng) LOD: Limit of detection (Gii hn xc nh) LOQ: Limit of quantitation (Gii hn nh lng) UNICEF: United Nations Children's Fund ( Qu nhi ng Lin hip quc) WHO: Wolrd Health Organization (T chc Y t th gii) Sha bi Trung tm Hc liu i hc Thi Nguyn http://www.lrc-tnu.edu.vn 5 DANH MC CC BNG Bng 1.1: Cc thng s vt l ca Asen ........................................................... 5 Bng 1.2: Mt s thng s vt l ca cc hp cht ca Asen ........................... 6 Bng 1.3: Tnh hnh nhim asen ti mt s vng quc gia trn th gii ..... 11 Bng1.4: TiuchunVit Nam vhm lngAs trong nc (Tiuchun Vit Nam 2007) ................................................................................ 15 Bng 3.1: Kho st vch o ca Asen ............................................................. 34 Bng 3.2: S ph thuc ca hp th vo cng dng n .................... 36 Bng 3.3: Kt qu kho st nhit tro ho ca Asen ................................... 38 Bng 3.4: Kt qu kho st nhit nguyn t ho mu ............................... 39 Bng 3.5: nh hng ca nng axit v loi axit ....................................... 40 Bng 3.6. Kho st nh hng ca cht ci bin ha hc ............................... 41 Bng 3.7: Kho st nng Mg(NO3)2 .......................................................... 42 Bng 3.8: Kt qu kho st s b thnh phn mu ......................................... 43 Bng 3.9: nh hng ca kim loi kim n ph hp th ca Asen ............. 44 Bng 3.10: nh hng kim loi kim th n ph hp th ca Asen ............ 44 Bng 3.11: nh hng ca kim loi nhm III, IV n ph hp th ca Asen .. 44 Bng 3.12: nh hng ca nhm kim loi nng n ph hp th ca Asen ..... 45 Bng 3.13: nh hng ca nhm kim loi mu n ph hp th ca Asen .. 45 Bng 3.14: nh hng ca tng cation......................................................... 45 Bng 3.15: nh hng ca nhm anion n php o ph hp th ca Asen . 46 Bng3.16:nhhngcatngcationvanionnphpophhpth ca Asen ........................................................................................... 47 Bng 3.17: Kho st khong tuyn tnh ca Asen .......................................... 48 Bng 3.18: Xc nh ng chun ca Asen .................................................. 51 Bng 3.19: Kt qu sai s v lp li ca php o ...................................... 53 Sha bi Trung tm Hc liu i hc Thi Nguyn http://www.lrc-tnu.edu.vn 6 Bng 3.20: Tng kt cc iu kin o ph GF-AAS ca Asen ...................... 54 Bng 3.21: a im, thi gian ly mu v k hiu mu ................................ 55 Bng 3.22: Hm lng kim loi As tnh theo mg/kg ...................................... 56 Bng 3.23: Kt qu phn tch i vi cc mu lp ......................................... 58 Bng 3.24: Mu thm chun ........................................................................... 59 Bng 3.25: Kt qu phn tch mu thm chun .............................................. 59 Bng 3.26: Kt qu xc nh Asen bng hai phng php GF AAS v ICP - MS................................................................................................. 60 Sha bi Trung tm Hc liu i hc Thi Nguyn http://www.lrc-tnu.edu.vn 7 DANH MC CC HNH V TH Hnh 1.1: Vng tun hon ca Asen trong mi trng ..................................... 4 Hnh 1.2: Cc con ng xm nhp ca Asen vo c th ngi .................... 14 Hnh 2.1: n catot rng ................................................................................. 28 Hnh 2.2: n D2 ............................................................................................ 28 Hnh 2.3: S h thng my quang ph hp th nguyn t ........................ 30 Hnh 2.4: Cuvet Graphite ................................................................................ 30 Hnh 2.5: H l Graphite nguyn tho mu ................................................ 31 Hnh 2.6: H thng my quang ph hp th nguyn t AA-6300 .................. 31 Hnh 3.1: th kho st khong tuyn tnh ca Asen .................................. 49 Hnh 3.2: Ph hp th ca Asen ...................................................................... 50 Hnh 3.3: th v phng trnh ng chun ca Asen .............................. 51 Sha bi Trung tm Hc liu i hc Thi Nguyn http://www.lrc-tnu.edu.vn 1 M U Hinnaymitrngnngnghipniringangchunhhng nghim trng bi s gia tng ph thi. Phn ln ngun ph thi cha c x luvomitrngt,nc,lmchomitrngngycngb nhim.Phthicngnghip,phthisinhhot,phthiccmkhaithc khong sn, ho cht nng nghip tn d i vo nc, vo khng kh ri tch ttrongt,lmchotbthoiho,lmgimnngsut,chtlngsn phm, c bit l sn phm nng nghip sn xut trn khu vc t b nhim c th tr thnh c hi cho ngi s dng.ThiNguynlkhuvccnhiumkhongsnangkhaithc,cc khu cng nghip ng thi cng l vng sn xut ch c sn. t, nc sn xutnngnghipkhuvckhaithckhongsn,cngnghipthngb nhim trong c kim loi nng. Ch c th b nhim mt s kim loi nng t t,nc,vkhngkh.Vvy,cnphiquantmnghincuvkimtra khng ch cc cht c hi, c bit l cc kim loi nng nh hng trc tip n sc kho con ngi. [17] XcnhAsentrongchxanhThiNguyn bngphngphp ph hp th nguyn t l mt trong cc nghin cu phc v mc tiu ni trn. Nhim v c th l:1. Tm cc iu kin ti u cho php o Asen 2.KhostccyutnhhngnphpoxcnhAsen.Tm khong tuyn tnh, xy dng ng chun. nh gi sai s v lp li gii hn pht hin, gii hn nh lng ca php o Asen. 3. Vn dng phng php xc nh hm lng Asen trong mt s mu ch khu vc Thi Nguyn, v nu ra mt s kt lun ban u v Asen trong ch xanh mt s khu vc ca tnh Thi Nguyn. Sha bi Trung tm Hc liu i hc Thi Nguyn http://www.lrc-tnu.edu.vn 2 Chng 1 TNG QUAN 1.1. Gii thiu chung v cy ch 1.1.1. c im v thnh phn Cy ch c tn khoa hc l Camellia Sinensis. Cy thng c trng ly l ti sc nc ung hoc ch bin theo nhng quy trnh nht nh thnh tr pha nc ung. Cy ch c mu xanh, cao 1- 6m, l mc so le, hnh tri xoan, di 4 - 10cm, rng 2 - 2,5cm, nhn gc, nhn t c mi nh, phin l lc non c lng mn, khi gi th dy, bng, mp kha rng ca rt u. Hoa to vi 5-6 cnh hoa mu trng, mc ring l nch l, c mi thm, nhiu nh. Qu nang thng c ba van, cha mt ht gn trn, i khi nhn nheo. NgungccychBcnvNamTrungQuc,ctruyn sangMianma,ThiLan,VitNam.Chctrngkhpnincta,tp trung nhiu Ph Th, H Giang, Thinguyn, Qung Nam- Nng cho ti c Lc, Lm ng. Cy a kh hu...