tach chiet va phan tich aflatoxin trong

TACH CHIET VA PHAN TICH AFLATOXIN TRONG

THU'C PHAM VA DUOC LIEU BANG SAC KY Al LUC MIlEN D|CH VA SAC KY LONG HIEU NANG CAO

Nguyen Thj Nguyet Thu. Duong Ngoc Diem. Do Thi ( ham.

Nguyen Thanh Tung. Nguyen Le Trang, Trinh Van Quy*

Vien Pasteur thanh pho Ho Chi Minh

* Vien Kiem nghiem Duoc Hd Npi TOM TAT

Chung toi sir dung cot sac ky ai luc mien dich (IAC) tu san xuat de lam sach mau trong phan tich aflatoxin va danh gia hieu qua sir dung cot cho viec xac dinh cac aflatoxin trong dich chiet cac mau ngo. lac. cam thao va giing bang phuang phap HPLC vdi dau dd huynh quang. Hieu suat thu hoi cua aflatoxin tdng so trong khoang ndng dp td 2,6 - 20.8 ppb dao ddng trong khoang 76 - 117%

vdi gidi han phat hien > 0,3 ppb va gidi han dinh lUdng > 1ppb. Nghien cuu nay cho thay cd the ap dung cot IAC de lam sach mlu trong dinh luang aflatoxin cua cac miu thuc pham va dUdc lieu vdi day du dp chinh xac va tin cay.

Tir khoa: aflatoxin, cot sac ky ai Idc mien d|ch, lam sach mau I. DAT VAN DE

Cac loai thdc pham va thao dddc cd the bi mdc do tiep xuc vdi dieu kien thdi tiet xa'u. cdn trung gay hai, thu hoach va van chuyen khdng dung each, khdng dii khd cung nhd dieu kien bao quan khdng du tieu chuan. Cac nam mdc gay nhiem cd the san xuat ra chat chuyen hda phu ddc hai. nhu mycotoxm. Trong sd hang tram chat chuyen hda trung gian ciia vi nam. chat dUdc quan tam nhieu nhat ddi vdi sdc khoe con ngddi va ddng vat la cac aflatoxin (AFL). AFL bao gdm 4 hdp chat cd ca'u true lien he la B, (AFB,), B2

(AFB2), G, (AFGj). va G2 (AFG2). Cd rat nhieu loai thuc pham bj phat hien nhiem AFL nhu ngd. lac. gao. hat dda. hat bi.

hat me. hat hudng dUdng, hat sen. hat tieu do. hat tieu trang. nhue dau khau, hdn hop gia vi. hdn hdp ngu cdc. dt...

AFL cung duoc tim thay tren cac loai

thao mdc [lj. To chiic nghien ciiu ve ung thU qudc te (IARC) da phan loai AFL vao nhdm cac tac nhan gay ung thd cho ngddi [2],

Tai Viet Nam tieu chuan gidi han aflatoxin tren thUc pham la 15 ppb (ng/gam mau) ddi vdi aflatoxin tdng sd va 5 ppb ddi vdi AFB1. chda cd tieu chuan tren dude lieu [13]. Theo tieu chuan cua cdng ddng chung Chau Au, gidi han afla- toxin tren thUc pham va dUdc lieu la 4 ppb ddi vdi aflatoxin tdng sd' va 2 ppb ddi vdi AFB1.

Tat ca cac ky thuat dung dinh lddng aflatoxin. trii ky thuat mien dich men (ELISA), deu can phai cd giai doan lam sach mau. Trong giai doan nay. ngddi ta thUdng diing ky thuat chiet xuat long- long hay chiet xuat pha ran. Bat Idi ciia hai ky thuat tren la dd chpn lpc thap. Gan day. cdt sac ky ai lUc mien dich diia tren khang the (Immuno affinity column Tac gia chinh: Nguyen Thi Nguyet Thu

Dia chi: 167 Pasteur. Quan ,3. Thanh phd lid ('hi Minh Dien thoai: (08) 38230352 - 148

Em;uI: ntnguyetthu05@yahoo.com

70 Tap chi Y hpc dir phdng, 'lap XX. so 5(113)

-IAC) da dUdc phat trien de thay the cho cac phu'dng phap lam sach cd dien. Ngoai cac u'u diem nhd de thao tac. dp thu hdi va dp lap lai cao. cdt IAC cd du diem vdo't trdi la cd do chon loc cao. giup de dang phan ti'ch aflatoxin tren cac nen mau phdc tap nhu mau thUc pha'm hay mau dddc lieu. Qua trinh phat hien aflatoxin dUa tren cac dac tinh phat huynh quang cua no. AFB] va Gj can bien ddi thanh dan xuat B2 a va G2 a cd kha nang phat huynh quang manh hdn. PhUdng phap ddn gian nhat la sii dung trifluoroacetic acid (TFA) de xuc tac phan ling. PhUdng phap HPLC vdi d&u do huynh quang la phUdng phap phat hien aflatoxin chinh xac va hieu qua.

Trong nghien ciiu nay, muc dich ciia chung tdi la danh gia kha nang phan tich aflatoxin bang each lam sach mau vdi cdt IAC tu san xuat va dinh lUdng bang phUdng phap HPLC vdi dau dd huynh quang.

Cac nen mau chung tdi chon Ida de phan tich la mau ngd. lac. cam thao va gdng.

II. PHUONG PHAP NGHIEN CUU 2.1. Vat lieu:

- Mau ngd, lac, cam thao. gtfng

• Hoa chat va dung mdi: AFL chuan don Bi, B2, Gi, G2; AFL chua'n tdng B,, B2, G,. G2 (B1:B2:G1:G2 = 1:1:0.3:0.3):

NaCI, TFA. methanol, acetonitnlc (tieu chua'n dung cho HPLC). Tween 20. Cdt sac ky ai luc mien dich san xuat tai phdng Hda mien dich. Vien Pasteur T.p I Id Chi Mmh.

2.2. PhUdng phap:

2.2.1. Phuang phap chiet mau:

Can 20g mdu + 4g NaCI + 100ml methanol 80%, lac 300 rpm trong 30 phut. Loc qua giay lpc thu'dng. Them vao

20 ml dich loc. -10 ml nude. Loc qua loc thuy tinh. Cho qua cot sac ki ai lUc mien dich 15 ml djch loc tUdng dUdng vdi 1 gam mau. (Ddi vdi mau cam thao do rat hao nUdc nen lupng methanol 80% dung chiet mau phai tang len gap ddi va cho qua cdt 30 ml djch loc sau ciing).

2.2.2. Phuang phap lain sach mdu bdng cot sdc ky di lUc mien dich:

De cdt IAC can bang tai nhiet dp phdng trong 30 phut. RUa cdt vdi 10 ml nUdc. Cho qua cot 1 5 ml dich loc. Riia cot bang 10 ml dich riia pha tii hdn hdp 62 ml nUdc + 8ml methanol + 70ml Tween 20.

Riia cdt tiep tuc vdi 10 ml nUdc. Day khi qua cho den khd cdt. Giai hap aflatoxin tren cdt bang 1ml methanol.

2.2.3. Phuang phap tao ddn xuat aflatoxin:

Dung khi nitd lam khd 1ml dung djch sau giai hap. Hda tan can vdi 2001 n- hexan va 50ml TFA. lac deu trong 60 giay, de yen 5 phut, sau dd thdi khd bang khi nitd. Hda tan lai vdi 1ml acetonitril 10%. Loc qua mang 0.45m vao chai nhd 1.5ml.

2.2.4. Phuang phap sac ky long pha dao phan tich aflatoxin:

May HPLC: Agilent 1100 Cdt:

Felipe XDB-Cl8-Agilent (4,6x150mm), kich thudc hat 5mm

Pha dong: ACN - HzO (25:75) Td'c dp ddng: 1 ml/phut Nhiet dp: 20°C

Dau dd huynh quang: Ex =360 nm;

Em = 440 nm

Ap suat chay: 135 bar The tich tiem: 10 ml

2.2.5. Phuang phap xac dinh gidi han phat hien va giai han djnh luang:

Cho cac lUdng khiic nhau (0.625;

1.25: 2.5; 5; 10 ng) ciia tdng loai aflatoxin lap chi Y hoc dir phdng. Tap XX. sd 5(113) %

BI, B2, Gl, G2 vao mau dich chiet va di qua cot IAC. Moi nong do dUdc phan tich tren 2 cot. Nong do thap nhat dddc phan tich tren 5 cot. Ve do thi bieu dien mile dp tddng quan tuye'n tinh gida lUdng aflatox- in cho qua cot va dien ti'ch peak thu dUdc tren sac ky do. Gidi han phat hien dUdc tinh nhd sau:

LOD (signal) = 3s/m

s: dp lech chuan ciia tin hieu tai lUdng thU nghiem thap nhat

m: he sd gdc cua dudng hdi qui tuyen tinh

Gidi han dinh lUdng dddc tinh:

LOQ = LOD x3

2.2.6. PhUdng phap xac dinh do tuyen tinh:

Cho cac lUdng khac nhau (2,5; 5; 10;

20; 50; 100 ng) ciia tirng loai aflatoxin B1 ;

B2, Gj, G2 vao mau dich chiet ngd va di qua cdt sac ky ai lUc. Mdi lUdng dUdc phan tich tren 2 cdt. Ve do thi bieu dien mdi tUdng quan tuye'n tinh giila lUdng aflatox- in cho qua cdt va dien tich peak thu dUdc tren sac ky dd. Xac dinh cac thdng sd dac trUng cho mdi tUdng quan tuyen tinh.

2.2.7. PhUdng phap xac dinh hieu suat thu hoi:

Hieu suat thu hdi dUdc tfnh theo cdng thiic:

A\

//%= xl00% f 1i vdi Al: lUdng aflatoxin thu dUdc sau khi qua cdt ai lUc

A2: lupng aflatoxin cho vao cot Cho cac ldpng khac nhau (2,6; 5,2;

10.4; 20.8 ng) ciia aflatoxin tdng sd' (B,:B2: G,:G2 = 1:1:0,3:0,3) vao mau dich chiet va di qua cdt sac ky ai lUc. Mdi lUdng dUdc phan tich tren 2 cdt. Xac dinh lupng

thu hdi bing phu'dng phap HPLC. Tinh hieu suat thu hdi theo cdng thdc (1).

HI. KET QUA

Ddi vdi phudng phap lam sach mau bang cdt IAC. qui trinh chiet xuat aflatox- in tit thUc pham va dUdc lieu theo hddng dan ciia cac nha san xuat cdt nhd Vicam (My), Romer labs (ao), cac td chdc tieu chua'n hda nhu AOAC, CBN, dUdc dien Anh, va tren cac bai cdng bd' thUdng la gidng nhau, chii yeu dung hdn hdp methanol-nUdc vdi ty le 80:20 hay 70:30.

Theo cac cdng bd tii FAP AS, sii dung cot sac ky ai liic cho phan tich aflatoxin ngay cang tang va hdn hdp nUdc — methanol la hdn hpp dung mdi chiet dUdc sii dung nhieu nhat khdng phu thudc vao loai mau xet nghiem [4]. Vi the' trong phan danh gia cdt IAC do vien Pasteur san xuat, chung tdi khdng khao sat hieu qua ciia qui trinh chiet xuat ma chiing tdi chi tap trung danh gia kha nang torn bat aflatox- in cung nhu kha nang lam sach mau ciia cdt IAC bang each cho true tiep chuan aflatoxin vao trong dich chiet mau sau ciing, trUdc khi dUa len cdt.

3.1. Do chon loc:

4 mau bdt ngd, lac, cam thao, giing gay nhiem vdi aflatoxin tdng so'tai lUdng 10 ng/ gam. Tren cac mau nay, cac pic aflatoxin sac net thu dUdc tai cac thdi gian ldu (phut) nhu sau AFG1 (2,774), AFB1 (3,830), AFG2 (5,006) va AFB2 (7,526). Cd the thay cac thay ddi nhd cua thdi gian lUu trong cac lan thi nghiem khac nhau lien quan den mdt sU thay ddi nhd trong nhiet dd hay trong thanh phan dung mdi. Tren sac ky dd ciia ca 4 nen mau khdng nhiem aflatoxin hau nhd khdng thay cac pic tap gay nhiem. (Hinh 1 va hinh 2)

72 Tap chi Y hoc dir phdng. Tap XX. sd 5 (113)

r

X I f

Hinh 1. Sac ky do cua mau ngo gay nhiem vai 10 ng aflatoxin tong so

A

I)

Hinh 2. Sac ky do cua cac nen mau khong nhiem aflatoxin:

(A) ngo, (B) lac, (C) gung, (D) cam thao

3.2. Giofi han phat hien va gi(Vi han co the phat hien 4 loai aflatoxin B1,B2, dinh hiring: Gl. G2 tai nong dp rat thap >0,3 ppb va Tren ra I nen mau. sau khi lam sach dinh ^k".ⁱⁿS ™^c mnu co nong dp aflatoxin bang rot IAC va dinh ludng aflatoxin > 1 ppb (bang 1).

bang HPLC vdi dau dd huynh quang. ta

Tap chi Y hoc dir phdng. Tap XX. sd 5 (113) 73

Bang 1. Gidi han phat hien va gidi han djnh luong cua aflatoxin tren nen ngd Sd (0,625) m LOD LOQ B1 2245 48198 0,14 0,42 B2 1212 62403 0.058 0,18 G1 2818 26990 0.31 0,93 G2 1145 46304 0,07 0,21 3.3. Do tuyen tinh: ca 3 loai aflatoxin B1.B2. Gl. va 2.5

Phudng phap tuyen tinh trong lOOng doi vdi aflatoxin G2 vdi he so tUdng khoang ham lUdng td 2.5-100 ng doi vdi duan kha cao R2> 0.976 (bang 2).

Bang 2. Mdi tuong quan tuyen tinh cua phudng phap djnh lUdng aflatoxin tren nen ngd

Aflatoxin Phuong trinh tuong quan tuyen tinh

He sd tudng quan (R²)

Khoang tuyen tinh B, Y = 51020 x - 41673 0,998 2,5- 100 ng B; Y = 60383 x + 26142 0,998 2,5- 100 ng G, Y = 33412 x + 19338 0,990 2,5- 100 ng

G2 Y = 40533 x 0,978 2,5 - 50 ng

3.4. Do thu hdi: quan sat 2,6-20,8 ng/gam, dp thu hdi ciia Ket qua do thu hdi dm vdi cac mdc dp aflatoxin tdng so dao ddng tii 94-105%

aflatoxin khiic nhau tren 4 nen miu: trdn nen man ngd, 94-117% tren nen ngd. lac. cam thao. giing dtidc liet ke tren mau lac. 45-55% tren nen mau cam thao bang 1,2,3,4. Trong khoang ndng dd va 82-100% tren nen mau giing.

Bang 3. Hieu suat thu hoi ddi vdi aflatoxin tdng so tren nen mau ngd Muc do Hieu suat thu hoi trung binh (%) - (CV%) Muc do

B, B2 G, G2 AF tdng

1 105 (1,4) 96 (2, 74) 97 (0.68) 67 (1,12) 94 (7,27) 2 113 (1.8) 89 (1.43) 109 (3,37) 86 (0, 77) 104 (2,29) 3 114 (0.27) 87 (1.05) 111 (10.99) 84 (6.7 7) 105 (4.98) 4 105 (0.42) 96 (1,92) 102 (7.34 ) 81 (7,99) 100 (0.33)

74 'tap chi Y hpc dir phdng. 'lap XX. so 5(113)

Bang 4. Hieu suat thu hoi doi vdi aflatoxin tdng so tren nen mau lac Mire do Hieu suat thu hoi trung binh (%) - (CV%) Mire do

B, B2 G, G2 AF tong

1 119 (1,77) 107 (6,68) 113 (7.25) 97 (7,46) 117 (8.38) 2 122 (0,033) 97 (4.37) 119 (0) 90 (2.37) 113 (0,27) 3 118 (2,18) 96 (4.41) 107 (2.64) 76 (3.72) 105 (0,74) 4 98 (1,14) 88 (2.96) 95 (2.76 J 81 (7.66) 94 (0.1)

Bang 5. Hieu suat thu hoi ddi vdi aflatoxin tdng tren nen mau cam thao Muc do Hieu suat thu hoi trung binh (%) • (CV%)

Muc do

AF tong

B, B2 G, G2 AF tong

1 67 (3,8) 19 (24.42) 58 (0,79; 46 (8,9) 55 (7.62) 2 56 (0,34) 28(24.94) 45 (6.74) 35 (7,37) 45 (0,72) 3 50 (8) 27(12,02) 56 (9,42) 40 (77,08) 48 (9,27) 4 54 (3,82) 38 (70,4) 59 (5.6) 32 (8,5) 51 (5,54)

Bang 6. Hieu suat thu hdi ddi vdi aflatoxin tdng sd tren nen mau gung Hieu suat thu hoi trung binh (%) - (CV%)

Mlie do B, B2 G, G2 AF tdng

1 131 (8.87j 86 (9.3) 59 (72,44) 56 (27.5) 82 (70,86) 2 113 (2,561 77 (6,25) 77 (8,52) 81 (2.49) 100 (9,27) 3 121 (5,82) 82 (9,56) 78 (7.02) 76 (8.69) 95 (3.73) 4 91 (2.7) 80 (2,38) 86 (3,9) 75 (4,28) 85 (2,04) MiCc dp 1 12.6 ng AFL tdng so): 1 ng/gAFBl va GI; 0.3 ng/gam AFK2 vd G2 Mac do 2 {5,2 ng AFL tdng so): 2 ng/gAFBl ra GI; 0.6 ng/gam AFB2 ua G2 Mite dii 3 t(I0.4 ng AFL tdng so): 4 ng/g AFB1 vd Gl; 1.2 ng/gam AFB2 vd G2 Mite dd 4 1120,8 ng AFL tdng so): 8 ng/gAFBl va G 1:2,4 ng/gam AFB2 va G2 Trdn nen mau cam thao hieu suat cai thien dang ke: > 94% ddi vdi aflatoxin thu hdi ciia aflatoxin tddng ddi thap. De BI: > 77% ddi vdi aflatoxin Gl: > 51% ddi khao silt anh hddng ciia mau len cot, vdi aflatoxin B2. Rieng vdi aflatoxin G2 chdng tin tien hanh xet nghiem tu'Ong tti hieu suat thu hdi van kha thap, dao ddng vdi lUdng mau cam thao qua cdt la 0.5 td 30-50%. Hieu suat thu hdi cua aflatox- gam thay vi I gam. Chung tdi nhan thay m tdng so trong khoang quan sat dat 76- hieu suat thu hdi ciia cac aflatoxin dddc 94% (hang 5).

Tap chi Y hpc dir phdng. Tap XX. so 5 (113) 75

Bang 5. Hieu suat thu hoi aflatoxin tong so khi cho ludng mlu la 0,5 gam qua cot IAC Muc do Hieu suat thu hdi trung binh (%) - (CV%)

Muc do

B, B2 G, G2 AF tdng

1 94 (2,24) 51 (0) 77 (6,38) 30 (20.8) 76 (5.78) 2 115 (4,28) 68 (4,75) 91 (7,8) 42 (77.9) 92 (5.97) 3 113 (7,86) 70 (2,02) 94 (9,7) 51 (2.77) 94 (2,38) 4 114 (3.7) 63 (6,7) 95 (8,7) 39 (7.83) 93 (5,79) IV. BAN LUAN

4.1. Do chon loc:

Tat ca cac sac ky dd cua mau khdng nhiem aflatoxin thu dtidc deu khdng thay cac pic tap gay nhieu nam trong khoang thdi gian ldu cua cac aflatoxin. Dieu nay chiing to dich chiet sau khi qua cdt IAC kha sach.

4.2. Gidi han phat hien va gidi han dinh hiring:

Phddng phap nay cd kha nang phat hien aflatoxin > 0.3 ppb va dinh lUdng aflatoxin d lddng >l ppb. Ket qua nay cho thay cd the phiu hien va dinh lddng afla- toxin trong mau d ham lUdng rat thap.

phu hdp vdi yeu rau kiem tra aflatoxin trong thUc pham.

4.3. Do tuyen tinh:

Qui dinh ham lu'dng tdi da doe to AFB, va cac aflatoxin (B1+B2+G]+G2) tdng so trin mau thuc pham tUdng Ung la 5 va 15 ppp. Qui dinh ham ludng tdi da ddc to AFB! va cac aflatoxin (Bi + IG-H^-KG) trong thdc an hdn hdp hoan climb cho gia siic, gia cam dao ddng tii 20 -200 ppb. De Ininh tdi da viec phai do mau hai lan chimg tdi tien hanh khao sat dp tuyen tinh cua phddng phap dinh lu'dng aflatoxin nam trong khoang 2.5 - 100 ppb. Ket qua khao sat cho thay trong khoang ndng dii tit 2.5-100 ng/cot cho 3

loai AFB,. A FIG. A KG, va 2.5-50 ng/cdt cho AFG2 cd su' tddng quan tuyen tinh giQa lUdng aflatoxin cho qua cdt va dien tich pic tudng Ung. sti phu thudc nay kha chat che the hien qua dudng thang hdi qui vdi he sd tUdng quan kha cao (R2 > 0.97).

4.4. Do thu hoi:

Kha nang ben ket giiia khang the tren cdt vdi aflatoxin tdng sd dddc danh gia tai cac lu'dng 2.6: 5,2: 10.4. 20.8 ng (B1:B2:G1:G2 =1:1:0,3:0.3). Cac lddng nay dUdc Ilia chon dUa tren tieu chuan gidi han ve aflatoxin trdn thiic pham. khac khe nhat la cua cdng ddng chung chau Au (2 ng/g ddi vdi aflatoxin BI va 4 ng/g ddi vdi aflatoxin tdng so) va ciia tieu chuan Vict nam (5 ng/gam ddi vdi aflatoxin BI va 15 ng/g ddi vdi aflatoxin tdng so). Hieu suat thu hdi kha tot ddi vdi 3 nen mau ngd, lac va giing (H% > 80%). Rieng ddi vdi mau cam thao kha thap (11% dao dpng xung quanh 40%). Hieu suat thu hdi thap cua cac aflatoxin trdn mdt so nen mau du'dc lieu dii dddc cdng bd' [1][7], nguyen nhan cd the do mdt so thanh phan trong dich chiet mau can trd qua trinh bdn ket ciia khang nguyen vao khang thd iron cdt. Do thu hdi cd the du'dc cai thien bdng each cho lu'dng mini nho bdn. sii' dung dich chief mau pha loang hdn qua cdt [H] hay dung the tich dung moi chiet nhieu hdn |11. Khi sii dung lupng mau qua cdt la 0,5 gam thay vi 1 gam. chung tdi nhan thay hieu suat 76 Tap chi Y hoc dir phdng. Tap XX. sd 5 (113)

thu hoi dUdc cai thien dang ke: 94-115%

doi vdi aflatoxin BI va 76-94% aflatoxin tong sd tai lddng tii 2.6 - 20.8 ng. Theo AOAC. do thu hdi dat yeu cau nam trong khoang 70 -125",, tai ham lddng lOg/kg [5]

va theo Codex [6], do thu hdi dat yeu cau nam trong khoang 70 -110% tai ham lddng 10 -100 g/kg va 60 -120% tai ham lddng 1- 10 g/kg. Do do do dinh lddng aflatoxin ti ong mau cam thao chung ta chi can giam lUdng mau cho qua cdt. Mat khac. chung tdi nhan thay trong phan Idn cac cdng thiic thudc ddng dUdc thanh phan cam thao chi chiem ham lUdng <50% nen khi khao sat cac mlu thudc til dddc lieu, thanh phan cum thao khdng anh hudng den ke't qua dinh lupng aflatoxin.

V. KET LUAN

Trong nghien cdu nay, chung tdi da danh gia kha nang sii dung cdt IAC tu san xuat de dng dung lam sach mau trong dinh lUdng aflatoxin tren nen mau thdc pham va dddc lieu. Qua trinh lam sach nay giam hau het cac pic tap gay nhieu cho phep phat hien va dinh lu'dng aflatoxin lot hdn. I lieu suat thu hdi cua aflatoxin tdng sd trong khoang ndng dp tii 2.6 - 20.8 ppb dao ddng trong khoang 76 - 1 17"n vdi gidi han phat hien >0,3 ppb va gidi han dinh lupng >lppb. Ket qua cho thay cot IAC do Vien Pasteur san xuat hoan toan thi'ch hdp cho muc dich lam sach mau de dinh lddng aflatoxin trong thUc pham va du'dc lieu.

TAI LIEU THAM KHAO:

1. Gomez-Catalan ,J. PE, Kalco G..

Borrego X.: Determination of aflatox-

ins in medicinal herbs by HPLC. An efficient method for routine analysis,.

Phytochem. Anal. 2005:16:196.

2. [ARC monographs on the evaluation of carcinogenic risks to humans.

International Agency for research on cancer, Lyon 1993:56:245.

3. Bd Y te , Quy dinh gidi han td'i da d nhiem smh hoc va boa hoc trong thiic pham. nha xuat ban Ha Ndi 2008 4. Michael J. O' Riordan: Comparison of

analytical methods for aflatoxin deter- mination m commercial chilli spice preparations and subsequent develop- ment of an improved method.. Food Control 2009:20:700-705.

5. hitp://www.aoac.org/dietsupp6/

Dietary-Supplement-web-site/

DSHomePage2.html

6. Codex Alimentarius. Joint FAO/WHO Food Standards Programme. Vol. 3.

Food Agriculture Organization; Rome.

Italy: 1993. p. 59.

7. Siu-Po Ip: Determination of aflatoxins m Chinese medicinal herbs by high- performance liquid chromatography using immunoaffinity column cleanup.

Improvement of recovery. Journal of Chromatography A 2006:1135:241 - 244.

8. AH N. I INI I. Saad li. . Safan K.

Nakajima M. , Yoshizawa T, Evaluation of a method to determine the natural occurrence of aflatoxins in commercial traditional herbal medi- cines from Malaysia and Indonesia,.

Food and Chemical Toxicology 2005:

13:1 763 - 1772.

Tap chi Y hoc dir phdng. 'lap XX. sd 5(113) 77

EXTRACTION AND DETERMINATION OF AFLATOXINS IN FOOD AND MEDICAL HERBALS USING IMMUNOAFFINITY COLUMN (IAC) AND HPLC

Nguyen Thi Nguyet Thu, Duong Ngoc Diem, Do Thi Cham.

Nguyen Thanh Tung. Nguyen Le Trang. Trinh Van Quy*

Pateur Institute in Ho Chi Minh city

* National Institute for Drug quality control We have developpec! an immunoaffini-

ty column for isolating aflatoxins from food and medical plants. We have evalu- ated the method using fAC clean up with HPLC and fluorescence detection for four different samples: corn, peanut, licorice and ginger. Recoveries of added total aflatoxins for these samples at levels

from 2,6 to 20.8 ng/g range from 76 to 117% with the detection limit is >0.3 ng/gam and the quantification limit is

>lng/gam. The overall results indicated that IAC will be suitable as a clean up tool for trace amounts of aflatoxins in food and medical herbal samples.

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