- Dd'i vdi cac HCTScd photpho : LUdng man dUde lam nhU tren Phan dich loc dUdc chiet bang diclometan 3 lan (lan lUdt 100, 70, va
chUng cat quay chan khdng (45^C) dich chiet sau khi cd can dUde hoa
tan bang 2 ml etylaxetat. Dung dich nay ditde dem xac dinh bang SKLM hoac SKK.
2.1.2.1.3. Man r a u qua.
- Ddi vdi cac HCTS-cd clo : (]^an chinh xac 50 g (± 0,1) rau, cat nhd, cho vao may xay sinh to. Them vao may xay sinh to' 100 ml toluen PA va 50 ml propanol-2 PA. Nghien 2 phiit vdi tdc do cao. Loe qua giay loc bang dd vao binh dung. Chuyen toan bo dich loc vao pheu chiet 500 ml. Them vao pheu chiet 250 ml dung dich n a t r i sunfat 2% . Like manh 1 phiit sau dd loai b() pha nUde . Lam lai qua trinh nay bang mot htdng 250 ml natri sunfat 2% nUa. Sau dd loai bd pha nUdc va ldp nhii.
- Ddi vdi cae HCTS- cd photplio : Can chinh xac 50g (± 0,1) rau vao cdc ciia may xay sinh to. Them vao dd 50 g natrisunfat khan va 100 ml etylaxetat PA. Ngliien 3 phiit vdi tdc dp cao . Loc qua giay loe bang dd vao binh ditng. Dimg them mot lUdng 20-30 ml etylaxetat nUa
de trang riia ba tren giay loe. Cd can toan bd (Uch loc hkng may eliUng
cat quay (45^C) dich cliiet sau khi cd can dUdc hoa tan bang 2 ml etylaxetat. Dicli nay dUde dem lam sach tren sac ki cot.
2.1.2.1.4. M i u lUdng thuc
Dd'i vdi m a n gao : Gao dUdc nghien nhd, say khd d 60-70^C trong 8 gid. Can 20g bot gao, them vao 20g natrisunfat khan. Tron deu hdn hdp, Sau dd dem chiet soxlet vdi 100 ml ete dau hoa trong 8 gid (4-5 siphon/gid). Sau dd dich cliiet dUdc dem cd can b i n g may chung eat quay de loai dung mdi chUng cat quay d 40-50*^C deii cdn khoang 1 ml dich nay dUdc lam sach tren s i c ki cot.
Dd'i vdi m a u md ddng vat chiia tren 5% md. C i t t h a n h titng mieng cd 10 x 10 mm. Can chinh xac 25g md cho vao pheu cd dUdng kinh 70 m m va dat pheu tren mot binh t a m giac cao cd va dat t a t ca vao tii say d nhiet do 65^C trong Idioang 4-8 gid, Hoa t a n md trong 100 ml ete dau hoa. Sau do lam bde hdi dung mdi d nhiet do 65-70^C (qua trinh nay xay ra khoang 2-4 gid). Dich chiet dUdc bd'c hdi den kiet dung mdi. Lay 0,2 - 0,3g md hoa tan trong 2ml ete dau hoa va dUdc dem lam sach tren sac ki cot.
2.1.2.1.6. M i u khdng khi
Cd nhieu qui trinh phan tich HCTS trong dat, nUdc, thUc pham. NhUng d nUdc t a hien nay qui trinh p h a n tich HCTS trong khdng khi bang phUdng phap SKLM,GC/ECD it dUdc de cap den. 6 nhiem khdng khi do HCBVTV ciing la van de dang dUdc quan tam. Do dd chiing tdi phai nghien ciiu qui trinh lay man, xii ly m a n de xac dinh h a m lUdng mot so HCTS trong Ididng Idii tai cac vung bi d nhiem.
- Lay m a n va xii ly m a n :
HCH, DDT (d dang bot) dUde hap t h u tren giay loc t h u y tinh (glassfiber) bang dung cu lay m i u khi filter. Td'c do hiit la 2 l/phiit va the tich khdng khi can lay la 50-100 1 (tuy theo h a m lUdng HCH va DDT trong Ididng khi nhieu hay it). Giay loc chiia m i u dUdc dUa vao pheu chiet cung vdi 50 ml ete dau hoa. Lac va ngam khoang 30 phiit . Tach lay dich chiet, Trang giay loc 2 lan, moi lan 25ml ete dau hoa, Gop cac phan ete dau hoa lai va cd can tren he thd'ng chUng cay quay chan Ididng, cdn khoang 2ml. Dich nay dUdc dem l a m sach , sau dd dUdc dem chay SKLM hoac SKK.
Wofatox va monitor trong khdng k h i dUde h a p t h u vao 20 ml etylenglicol b i n g d u n g cu lay m i u k h i Impinger. C h u y e n 20 ml dung dich h a p t h u vao pheu chiet 250 ml. S a u dd d u n g nude eat 2 lan t r a n g d u n g cu n h i e u lan va ddn vao pheu chiet ( k h o a n g 80 ml). Cho vao p h l u chiet 50 ml diclometan, l i c m a n h 1 phiit. Luu lai pha
diclometan. Tiep tiic chiet 2 lan nita mdi lan 50 ml diclometan. Loai bo pha nUde va etilengiicol. Cd can dich chiet tren he thdng chUng cat quay chan khdng cdn khoang 2 ml. Dung dich nay ditdc dem lam sach "idng nhu nguyen t i c chung.
2.1.2.1.7. M i u sUame :
Chiing tdi khdng thay cdng bd qui trinh phan tich sUa me nen da nghien ciiu lap dUng qui trinh phan tich DDT trong sUa me. Lay 250 g sUa me cho vao pheu chiet l i e ky, deu, nhe n h a n g vdi 50 ml ete dau hoa lie mot phiit. Lap lai qua trinh chiet 3 lan, mdi lan 50 ml ete dau hoa (chii y : khi lac t r a n h sinh bot ), Gop 3 phan ete dau hoa lai, lac riia vdi 50 ml nUdc. Sau dd lac phan ete dau hoa da riia vdi 20g Na2S04 khan de loai nUdc. Loe ete dau hoa vao mot binh qua le, trang rita pheu chiet b i n g 10-15 ml ete dau hoa khan. Ddn cac phan ete dau hoa vao binh qua le, cho bay hdi den can tren he thdng ehUng cat chan khdng. Dich chiet sau khi cd can dUde hoa t a n b i n g 2 ml hexan. Dich nay ditdc dUa qua cot nhdm oxit de lam sach.
2.1.2.1.7. Nghien ciiu dieu kien chiet
Them 45 microgam DDT, HCH chuan (pha trong n-hexan) wofatox chuan ( pha trong etylaxetat) vao 25g dat vita dUdc phan tich xong ( m i u dat khdng cd HCTS). Them 45 microgam DDT, HCH, wofatox chuan vao 50 g r a u vita dUdc p h a n tich xong. thUc hien qua trinh chiet tach n h u da md t a d phan tren. Sau mot gid tach rieng dich chiet ra, lam sach va xac dinh ham lUdng DDT, HCH, wofatox trong titng phan doan cua titng ddi tUdng m i u . Ket qua chiet dUdc the hien d bana' 2
Bang 2 : Ket qua chiet HCTS tut cac doi tUdng trong moi trUdng a mau ai xauh ^lii thao yn chua Vuoc Ditt )P-DDT H(^H Vi)fatox
Hoa chat true sau trong mau