T R U O N G DAI H O C D O N G T H A P Tap ch! Khoa hoc sd 41 (12-2019) NGHIEN C t r u PHirONG PHAP SAC KI KHI GHEP KHOI P H 6 KET HOnp KY THUAT KHONG GIAN HOfI (HS-GC-MS) DE PHAN TICH TRIHALOMETHANES TRONG N i r 6 c MAY TAI TIIANH PHO H 6 CHI MINH
• Vo Thi My Nga", Vo Thuy Vi'"' Tom t i t
Phuong phdp sac ky khdi phd Id mot trong nhieng phuong phdp duoc lua chpn di phdn tich Tnhalomethanes (THMs) trong nude mdy Ngdy nay, viec kit hgp sac ky khi khoi pho vdi ky thudt khong gian hoi (HS-GC-MS) cd nhiiu uu diem. Ddy Id phuong phdp hien dai di phdn lich THMs trong nude md khdng cdn qua bude tach chiit bang dung mdi gay d nhiem moi trudng. Qua qud trinh khdo sdt da cho thdy do nhay cao nhdt tgi cde dieu kien sau- nhiit do u 52°C, thdi gian u 41 phut, ndng dp muoi NaCl 3,5 g/10 ml. Vdi diiu kien tdi uu ndy, dp dung xdc dinh THMs trong mpt sd mau nude mdy tren dia bdn thdnh phd Hd Chi Minh
Tie khoa: Chlorine; trihalomethanes; THMs, HS-GC-MS; ky khuat headspaee.
1. Dat van de
LTU diem eua ky thuat khdng gian hoi kh6ng gay 6 nhiem m6i truong do chit phan tich de bay hoi se hda hoi tiioat khdi nen mau ma khdng can dimg dung m6i de chiet tach. Khi ket hpp ky thuat khpng gian hoi vdi sic ky khi ghep khoi pho (HS- GC-MS) cho dp nh^y eao, Vi vay, ky thuat khdng gian hai dupe six dyng nhieu trong nhirng nghien eiiu gin day [5].
Trihalomethanes (THMs) la cac san pham phu tao thanh tiong qua trinh khu trimg nude bang cac hop chit chua clo. Qua mpt so khao sat dich te hpe ngudi ta da nhan thay c6 sy lien quan giiia eae benh ung thu bang quang, ung thu rudt va dot bien gen vdi nhiing san pham phu nay, Hien nay, mpt so nha may da diing ozone hoac tia cue tim de kbit khuan nude nhung sau dd van phai su dung cac hop chat eiia clo hay brom de duy tri lypng boa chat khu khuin du, chong tai nhiem ban tien dudng ong van ehuyen. Do do, van de xac dinh ham lupng trihalomethanes cd trong nude may la rat can quan tam [2].
De danh gia miic dp nhiem THMs, chiing toi tien hanh khao sat mpt so m^u nude dupe lay tic mpt so cac quan d thanh pho Ho Chi Minh
2. Noi dung nghien cihi 2.1. Thiet bi dung cu va hoa chat - May sic ky khi GC-MS Agilent 7890 ket noi '"' Truong Cao ding Cong Thtrong mien Trung.
*"' Tmcmg Dai hoc Cong nghiep Thiic pham Th^nh pho Ho Chi Minh
bp kh6ng gian hoi headspaee G1888, cot mao quan VRX (Supelco) dai 60 m, dudng kinh 0,32 pim.
- Cac dyng cy nhu lo 23 ml, nap va vanh nhdm chuyen dimg cho ky thu§t khong gian hoi cua Agilent, pipet 10 ml. Micro syring 10 ml,
- Dung dich chuin gdc VOC 1000 ppm cua Supelco (so 16 LB65604) gom 23 chit trong do cd Chloroform, Bromodichloromethane BDCM, Dibromoehloromethane DBCM va bromoform, bao quan lanh d 5''C.
- Npi chuin l-bromo-4-fluorobenzene (IS) 1000 ppm.
- NaCl (Merck), nude sieu saeh da loai bo chat hiiu CO bang may Millipore MiliQ.
2.2. Quy trinh thuc nghiem 2.2.1. Quy trinh Idy vd bdo qudn mau Dyng cu lay mau dupe sit dung la cac chai thuy tinh 100 ml, nip van, ed ldp dem PTEF saeh say khd d lOS^C trong 3 gid, de ngupi, day nap that chat kin, Mau nude liy diy chai va nut lai that chat, khdng tiao doi khi (khdng thay bot khi) Bao quan mau d nhiet dp tit O^C - 4''C khong qua 48 gid. Sir dung Natri ascorbat tii 0,01 den 0,02 gam de loai bd 1 mg clo du,
2.2.2 Chudn bi mau
Liy chinh xac 10 ml dung dich chuin hoac mau eho vao Ip 23 ml dimg cho bd khdng gian hoi (Agilent), them muoi NaCl vao, ddng nap lai.
2.2.3. Phdn lich trin thiit bi GC-MS Trihalomethanes (THMs) la cac hpp chat don
TRUCfNG DAI HOC DONG THAP Tgp Chi Khoa hoc so 41 (12-2019) cacbon chua cac nhdm the halogen vdi cdng thiic
chung CEXy frong do X la cac nguyen to halogen nhu F, CI, Br, I hoac la ket hpp cae nguyen to nay vdi nhau (H. A. Marie, 2014) Cae THMs c6 mat pho bien frong nude uong gom cac dang khae nhau nhu: chloroform (CHCI3), bromodichloromethane hay dichlorobromometiiane (CHBrCl^) (BDCM), dibromochloromethane hay chlorodibromomethane (CHClBr^) (DBCM) va bromoform (CHBr,)
- Chuong trinh nhiet: nhiet dp dau: 40°C, tPc dp gia nhiet la 10°C /phut, nhiet dp euoi 200°C giii 3 phut. Ty le chia ddng: 1:10,
- Nhiet dp inlet: 200°C, khi mang He 99,9999%.
- Diu dd MS: Nhipt dp nguon ion hda 230°C, nhiet do bp tir cue 150°C, thpi gian fre dimg mdi:
9 phut. Minh ipn sim: Chloroform (83, 85 m/z), BDCM (83, 85), DBCM (129,127), Bromofonn (173, 254), IS (95,174).
3. Ket qua va thao luan 3.1. Toi uu dieu ki^n
Vdi muc tieu tim dieu kien hda hoi chat phan tich tot nhat de thu dp nh^y cao, Chimg tdi tien hanh khao sat anh hudng cua ba yeu td nhiet dp, thdi gian nung va nong dp muoi dong thdi bang ma fr|n yeu to toan phin, Sau do, toi uu hda cac dieu kien bing phuong p h ^ leo doc Box-Wilson [1], [4].
3 1.1. Cdc bude thuc hien bdi todn quy hoach Chpn cac yeu to inh huong: Z^: Nhiet dp nung frong bp kh6ng gian hoi, °C; Z^: Thdi gian nung, phut, Z3: nong dp mupi (g/10 nil), Chpn cac ham myc tieu Y: tcng dien tich bon chat THMs.
Chpn mien khdo sat: Theo tai lieu tham Vhkt va dieu kien gidi ban cua headspaee, chiing tdi tien hanh khao sat frong cac dieu kien sau (Bang 1).
Xay dyng ma fran quy hoaeh vdi bien io x^
TYT.23 (Bang 2),
B ^ g 1. Miln khao sdt cic yeu to kah hvorng
C^cmiii:
Miic tren (+1) Miic CO s6 (0) Muc duoi (-1) K h o a n g b i e n tMeti (A)
Cac yeu to anh hudng Nhiet I g
(Z , )>C 100 70 40 30
Thoi gian (Z,),phiit
60 35 10 25
NkgA^
muoi (Z3), (g/lOml)
3,5 1,75 0 1,75
So TN 1 2 3 4 5 6 7 8 9 10 11 12
B i n g 2, Ma t r ^ quy ho^ch thijn: n
X. X,
-1
0 0 0 0
X,
-1
0 0 0 0
X.
-1 -1 -1 -1
0 0 0 0
x„
1 -1 -1 1 1 -1 -1 1 0 0 0 0
x„
-1
-1
-I
0 0 0 0
x„
-1
0 0 0 0
^ i f i n 2^
X,B -1
-1
0 0 0 0
Y 534461 490417 612423 387614 148076!
967816 1731153 1261470 1600671!
1557601 1555343 1586726 Qua cae tinh toan ta dupe phucmg trinh hoi quy mo ta gin diing nhat vdi thuc nghiem noi len anh hudng eua 3 yeu tP den qua trinh cd d^ng:
Y=933265- 156436X,+64900X2-H427037X3 - 89223X,3-K71110X23 +28004X,33
Ket qua k h ^ sat eho thay nhiet dp vanong do muoi c6 anh hudng qua 1^ vdi nhau. Chiing tuong tac nghich. Ham dat gia tri max khi nhiet do gidm va nong dp muoi tang.
3.1 2. Toi uu hda thuc nghiem Toi uu toi hda quy trinh k h ^ sat ham myc tieu bing phupng phap leo doc.
Yeu to Z, ed he s6 b,A, Idn nhat nen bude chuyen dpng cua yeu to Z, dupe tinh nhu sau:
5,= 0,3*AZ,=0,3*30=9,
Cac bude chiQ^en dpng euayeu tP Z^, Z^ dupe tinh theo eong thiic:
s,=s, M l 3; 5, . »,A,
Trong do S^ la buoc nhay cua yeu to thu i; b, la h? so hoi qui ciia cac yeu to tuong quan; A^ la k h o ^ g bien thien cua timg yeu to tuong ung. Cac gia tri tinh toan the hien trong Bang 3. Dien tich bon chat TEIMs la cao nhat voi nhiet do nung 52°C trong thoi gian 41 phiit vanong do muoi la 3,5 g/10 ml.
88
TROCSNG D A I H O C DONG T H A P Tap chi Khoa hpc so 41 (12-2019) B i n g 3, Toi u u h o a cac t h i nghifm tir t a m m a t r ^
Thi nghiem k^ tiep
TN9 TNIO T N U
Z, 61 52 43
Z j
28 41 44
Z, 3,2 3,5 3,5
Dap irng Y 2271016 2440568 2206356 3.2. X^y dyng dirdng chuan
^^..^
*"4lT«?f" •
. - < ^ . ^ , •tMotofcrai
^ . . ^ R ' = 0 » » MBDOA
-.'^^^''Vl^''''''^-*
^ A ^ ''"R^"o"»r"
' * * Ci«;u ^ '" "
Hinh 1. Sirorng chu4n c^c THMs Dudng chuan xae dinh cac chat THMs dupe tien hanh tren day dung dich chuan cd nong dp tir 1 den 100 pg/l vdi npi chuan l-bromo-4- fluorobenzene c6 nong dp 10 ^ig/1 (Hinh 1), Trong do: CS/CIS la ty le nong dp chat chuan/ nong dp npi chuan; AS/AIS la ty le dien tich pic cda chat chuan/dien tich pic cua npi chuan,
3.3. Giffi h^n phat hi^n va dinh Iir^ng Gidi h?in phat hien LOD (Limit of detection) va dinh lupng LOQ (Limit of quantitation) dupe tien hanh bang each do nhieu lan dung dich co nong dp nhd gan b ^ g gidi han phat hien. Cac gidi han phat hien dupe tinh theo cdng thuc sau:
C C Z,0D = 3*—s!s-; LOQ = 10*-^^.
S/N S/N Trong dd S/N: la ty le tin hieu ti-en nen (3< S/
N<10), C la nong dp do (Bdng 4).
B ^ g 4. Gidi han phdt hi£n va gidi han dinh lirQiDg cua phmmg phip
3.4. Danh gia do chinh sac cua phutmg phap Phan tieh s i c ky do cua dung djch chuan THMs dupe md ta nhu Hinh 2
GiStii
c..
(llg/1) S/N LOD (lig/1) LCX3
<ng/i) Chlorofomi
0,2 6,2 0,10
0,32 BDCM
0,5 9,5 0,19
0,64 DBCM
0,5 8,2 0,18
0,61
Bromofomi 0,5 7,8 0,18
0,60
JL
Hiah 2. SSc ky do dung dich cbuan THMs 10 ^g/]
phan tich bSng pbuong ph jp HS-GC-MS Do dung dupe danh gia qua hieu suat thu hoi.
Thi nghiem xac dinh hieu suat tiiu hoi dupe tien hanh tai ba muc nong dd la 5,10 va 50 pg/1. Thuc nghiem tien hanh bSng each them chuan vao cae nen mlu tiiuc te. M6i muc dupe thue hien Igp 1^
ba lan Ket qua khao sat trinh bay tiong BMg 5, Bang 5. Ket qua khko sat dp l$p lai
va h i ^ suat thu hoi
Chat
Chloroform BDCM DBCM Bromofoim
Nong 36 them vao S|lg/I
Hsra
(%)
99,5 108,8 103,7 103,8
USD
%)
11.7 16.6 5.5 4.5
NoDg do them vao 10 fig/l H S I H
(%)
105,5 104,6 110,6 105,2
RSD
(%)
12,6 8,1 10,1 11,9
Nong do them vao SOfigfl HSTH
(%)
109,8 104,1 106,6 109,3
RSD
(%)
5,1 9,0 8,8 9,1 Hieu suat thu hoi cae chat tnhalomethanes cua phuong phap khdng gian hoi tai eae nong dp khap sat trong khoang tir 99 -110% va thupe k b p ^ g eho phep theo quy dinh cua AOAC (Association of Official Analytical Chemists - Hiep hpi cac nha hoa hpe phan tieh). Theo ket qua dat dupe, dp lech ehuan tucmg doi RSD (Relative Standard Deviation) cua cac phep phan tieh eao nhat la 16,6%, thap hon khoang RSD chap nhan dupe theo yeu cau cua AOAC ve danh gia tieu chi do 1 ^ (<21%). Nhu vay, quy trinh phan tich da xay dung de xac dinh cac hop ehat trihalomethane cd dp lap dam bao tin cay.
TRUCfNG DAI HOC DONG THAP Tap chi Khoa hpc so 41 (12-2019) 3.5. Ket qua phan tich mot so mau nvffc
may tren dia ban thanh pho Ho Chi Minh Ket qua phan tich mpt so mau nude tren dia ban thanh phd Ho Chi Minh eho thay Chloroform, BDCM ed ham luong nhd hon so vdi tieu chuan cho phep cua Bo Y te Viet Nam (Bang 6) Theo
hudng dan ciia To chue Y te The gidi va Bp Y te Viet Nam quy dinh gidi han ndng dp cac Trihalometiiane cho phep c6 tiong nude nhu sau;
chloroform 200 pg/l, Bromodichloromethane 60 ng/1, Dibromochloromethane 100 ng/l va bromoform 100 pg/1.
Bang 6. Kit qua phan tich cac THM tai mot s^ dia dilm if thanh ph^ Ho Chi Mioh Ten mau
Tran khanh Dir - Quan 1 Linmg Nhir Ngpc - Quan 5 Trinh Dinh Trpng - Quan Tan Phu Le Dai Hanh - Quan 11 Dudng 3/2 - Q u i n 10
X6 Viet Nghe Tinh - Qujn Binh Thanh Ba Huyen Thanh Quan - Quan 3 D^t M a i - Quan Binh Tan Thanh Lpc - Quan 12 Truong Dinh - Quan 1
Dora vi
^g/l ng/l
^g/l (Tg/l Hg«
ligfl
\ilA Hg/l
^g/l ng/l
Chloroform 21,7 90,0 128,1 95.6 31.6 30,7 20,4 162,4 109,4 27,7
B D C M 5,2 15,9 14,4 12,6 7,4 7,3 4,6 15,1 14,2 6,5
DBCM 0 0 0 0 0 0 0 0 0 0
Bromofomi 0 0 0 0 0 0 0 0 0 0 4. Ket luan
Nhom nghien euu da tim dupe mdt so dieu kien thuc nghiem khi sir dung phuong phap sac ki khi ghep khdi pho ket hop ky thuat khdng gian hoi de tiem mSu. Ap dung phan tich chinh xae ham luong cac hpp chat Tribal omethanes-THMs trong eae mau nude tren dia ban thanh pho Ho
Chi Minh. Dp lech chuan tuong doi khi tinh toan hieu suat thu hoi giiia cae lan do dudi 20% chung td cac ket qua do sai lech khdng ldn va eho dp ehinh xac cao
Ket qua nghien cuu khang dinh ham luang cac ehat THMs trong cae mau nude van d muc cho phep theo QCVN 01:2009/BYT,/.
Tai lieu tham khao
[1]. Nguyen Canh (1993), Quy hoaeh thuc nghiem, Nha xuat ban DHBK TR Ho Chi Minh.
[2], A. C Gonzalez (2011), "Gas Chromatography Analyses for Tribalometiianes' An Experiment Illustiating Important Sources of Disinfection By-Products in Water Treatment", Journal of Chemical Education, (Np.78), pp. 123-131
[3], H, A, Mane (2014), Trihalomethane Definition, Journal of International Eduation, (No.23), pp, 235-241.
[4], C, S. Sa, R A Boaventura, I B. Pereira (2011), "Analysis of tnhalomethanes in water and air from indoor swimming pools using HS-SPME/GC/ECD", Journal of Environ Science Health, (No.46), pp, 355-363.
[5], Ngd Van Tir (2009), "Su dung ky thuat khdng gian hpi ket hpp GC-ECD (HS-GCECD) de xac dinh Trihalomethanes trong nude may tai Thua Thien Hue", Tap chi khoa hpc Dai hpc Hui, (So 50), ti-. 165-174
9 0
T R U Q N G DAI H O C DONG T H A P Tap chl Khoa hpc SO 41 (12-2019) STUDYING THE GAS CHROMATOGRAPHY OF SPECTROMETRY MASS
COMBINED WITH THE HEAD-SPACE TECHNIQUE TO ANALYZE TRIHALOMETHANES IN HO CHI MINH CITY
Summary
The gas chromatography of spectrometry mass is one of the selected methods for analyzing trihalomethanes (THMs) in supplied water Today, the combination of this method with the head-space technique (HS-GC-MS) has been found to have many advantages It is a modem method for analyzing THMS in water without the solvent extraction step, \^4lieh makes environmental pollution. The results showed the greatest sensitivity obtained in the following conditions: incubation temperature 52°C, incubation time 41 mins, NaCl concentration 3,5g/10ml These optimal conditions are used to analyze THMS in some supplied water samples in Ho Chi Minh city.
Keywords: Chlorine, trihalomethanes, THMs, HS-GC-MS, headspaee technique.
Ngdy nhdn bdi: 01/7/2019; Ngdy nhdn lai. 19/8/2019, Ngdy duyet ddng: 05/12/2019.
