Sử dụng chất cải biến hóa học và kỹ thuật tiêm mẫu nhiều lần trong quang phổ hấp thụ nguyên tử lò graphit xác định một số nguyên tố kim loại trong nước biển

Tiiu ban Sinh thdi, Mdi tnr&ng vd qudn ly Bien SU'DVNG CHAT CAI BIEN HOA HOC VA KY THUAT TIEM MAU NHIEU L A N T R O N G QUANG PHO HAP THU NGUYEN TU* L GRAPHiTXAC DINH MOT SO NGUYENTO KIM LOAI TRONG NirOC BIEN Nguygn Binh Thuat' Biii Minh Ly', Vo Mai Nhu Hieu', Nguyen Thj Cim Binh^ (l)Vi?n Nghien cim va U"ng dung cong nghe Nha Trang, 02 Hung Vuong - Nha Trang (2) Hpc vien Hai quan Nha Trang, 30 Trin Phii - Nha Trang Email: ngdinhthuat@nitra.ac.vn Tom tk Dd thiet Igp cdc thong so tdi uu cho qud trinh n^yen tu hda v&i Ap thuat tiem mdu nhiiu Idn kit hgp sir dung chdt cdi biin ddi hoa hgc vd he thdng hi?u chinh nin de xac djnh true tiep hdm lugng cdc kim logi di bay hai nhu Cd vd Hg cdc mdu nu&c biin bdng phuong phap quang phd hdp thif nguyen tu Id graphit (ETAAS) Anh huahg cua nhieu nin cdc mudi v6 ca nu&c biin la rdt quan trgng dd gidm ddng ki six dung hdn hgp chdt cdi biin hoa hgc v&i ty le Pd(N03)2:axit ascorbic = 20:200 (mg/l) cung v&i hai he thdng diiu chinh nen: hieu chinh nen dateri [deuterium arc background correction (DABC)] vd hi$u chinh nin Zeeman [Zeeman effect background correction (ZEBC)] Ben canh ky thugt lam giau mdu bdng ky thuat lam khd mdu nhiiu lan (reconcentralion) ket hgp chuong trinh nhiet ddi vai kim logi cdc di bay hai nhu Cd vd Hg tuone ung vai nhiet dg than hda Id 500°C vd 30(fC; nhiet dg nguyen tu hoa 1500 C vd 1400^C dd xdc dinh hdm lugng cdc kim logi dual dgng vSt (ca fig/l) Abstract USE OF THE CHEMICAL MODIFICATION AND THE MULTI-INJECTION TECHNIQUE IN THE ELECTROTHERMAL ATOMIC ABSORPTION SPECTROMETRIC DETERMINATION OF METALS IH SEA-WATER Having established the optimum parameters for the atoms of multi-injection technique combine use of chemically modified and corred system for determining direct metal content as Cd and Hg in sea water samples by atomic absorption spectroscopy graphite furnace (ETAAS) The effects of noise background to the inorganic salts in seawater is very important to have significantly reduced when using a mixture of chemical modified with ratio Pd(N0^2:ascorbic acid = 20:200 (mg/l ) along with two control systems background: deuterium arc background correction (DABC) and Zeeman effect background correction (ZEBC) Besides techniques to enrich by II3 Hoi mhi Khoa hgc va Cdng nghe biin loan quoc lan thir reconcentralion combines program the heat for 'hetnetals such as Cd andHg corresponds to a charring temperature of SOCfC and 30(fC: atomisation temperature of ISOCPC and 140CPC were determined concentrations of trace metals in the pg/l Keywords: direct trace metal determination: sea-water: chemical modification: background correction: electrothermal atomic absorption spectrometry I M d BAU Thuy ngan, cadimi co m6i truong thong qua Cac hoat dong ciia tu nhien va nguoi (chu ylu tit cac boat dong ciia cac nganh cong nghiep hoa hgc, cac nha may san xuat thijt bi dien, cong nghi?p che tjo son, cong nghiep chit deo Ham luong thuy ngSn, cadimi moi truong biln dang co chilu huong gia tang nhung nam gan day, nong cua chung cao nuoc se anh huong den doi song ciia sinh v^t bien Khi cac sinh vat bi nhiem doc, gidng nhu mot chu trinh sinh hgc den lugt chiing Iai la nguon thtic an cho ngucri va chiing se dugc tich luy vao co the nguoi voi nong cang cao [1] Phucmg phap quang phi hip thu nguyen tii nhiet dien (ET-AAS) voi nhung dac tinh mi vi?t nhu: dg chgn Igc, nhay va chinh xac cao, gioi ban phat hign thap, c6 the xac dinh dugc cac kim loai dang vet Tuy nhien phuong phap van co nhugc diem co ban la chiu anh huong boi cac nhieu khong thugc nguon gfic ph6 gay dan den hieu suat nguyen tii hoa thap Nham dat dugc dO xac thuc va dg nh^y cao, phuong phap ET-AAS cung voi ky* thuat 16 graphit co d§ on djnh (stabilized temperater platform fiimace-STFF) va cac chat cai bien hoa hgc da dugc nghien cuu ap dung nMm loai tru anh huong ciia cac nhieu khong thugc nguon goc Cac chat cai bien hoa hgc dugc them vao mau phan tich va mau chuan se lam thay doi dac tinh nhiet hoa cac kim loai phan tich hoac/va cac chat tao nen de loai tru ho^c giam bot cac nhilu [2] Trong nuoc biln thuy ngan va cadimi t6n tai duoi dang vlt va sieu vlt nin h6n hgp muoi la hon hgp phiic tap gay nhilu manh, vi vay mu6n nang cao hieu qua xac dinh cac kim loai cin phai tiln hanh lam giau mlu bang cac phucmg phap nhu tach, chiet, cgng ket, chung cit, kit tua cac kim loai cin phSn tich Nhung cac phuong phap de nhiem ban dan hoac lam mit nguyen tl cin phan tich din din sai s6 he thing cua phep Ion Vi vay, phucmg phap lam giau nguyen tl phan tich cuvet graphit (in-situ) bang ky thuat tiem mau nhilu lin kit hgp sir dung chit cai biln dli boa hgc va he thing hi?u chinh nen se cho phep xac dinh true tilp ham lugng cac kim loai dl bay hoi nhu Cd va Hg cac mlu nuoc biln bing phucmg phap quang phi hip thu nguySn tu 16 graphit (ETAAS) ma khong cin xir ly mau truoc [4] Tiiu ban Sinh thdi, Mdi tru&ng vd qudn ly Biin 11 II PHirOfNG PHAP Dung cu v^ thi^t bi - Can phan tich 0,000lg (Scaltec - Germany) - Khi argon 99,99% cua Xi nghiep hoi ky nghe Nha Trang - Mang loc co kich thuoc 0,25|im (Whatman - Japan) - May loc nuoc sieu sach nu6c EASY pure II - Lo graphit loai "Omega platform extended lifetime cuvettes" (Germany) - Mdy quang ph6 hSp thu nguyen tCr cing cac bo phSn di kem: Thermo ElementalModel Solaar M6 Dual Zeeman Atomic Absorption Spectrometer, Furnace autosampler FS95, den catot rong HCL data Coded, dugc dieu khien bang may tinh Intel Pentium V 3,06 GHz (h6 trg sieu phan ludng HT); 512MB RAM; 40 GB HDD; 1,44 MB FDD voi phan mem dieu khien Solar Version 27 - Cac che do quang ph6 dugc dan bang 2.1 Bdng Cdc diiu kien quang hdp thu nguyin tu su dung Id graphit logi "Omega platform extended lifetime cuvettes " [3] Thong so Cd Hg ^(nm) 228,8 253,7 Dg rgng khe (nm) D,S 0,5 Thoi gian (s) 3 Kieu Dien tich Dien tich Dong den (%) 50 90 Hoa chat - Dung dich chuin Cd, lg/1 duoi dang Cd(N03)2.4H20 HNO3 0,5M (Fluka) - Dung dich chuin Hg, lg/1 duoi dang Hg(N03)2.H20 HNO3 2M (Fluka) - Dung dich Pd lg/1 duoi dang Pd(N03)2 HNO31M (Fluka) - Dung dich acid ascorbic lg/1 nuoc (Roana-Hungary) - Hon hgp Pd(N03)2:ascorbic acid = 20:200mg/l dugc sir dung de lam chat cai bien hoa hgc cho nguyen tl Hg va Cd - Dung dich nuoc biln ting hop co nlng 34,2%o: can 32g NaCl + 14gMgS04.7H20 ^- 0,I5g NaHC03, tat ca cac hoa chat tren dugc hoa tan OOOmI nuoc sieu sach ,[g Hgi nghj Khoa hoc vd Cong nghe biin todn qudc I Xay dung 6a