10.14. Xc nh dung mi tn d

 

Th nghim m t trong Ph lc ny xc nh dung mi tn d trong cc trng hp:

1- nh tnh dung mi nhm 1 v dung mi nhm 2 tn d trong dc cht, t dc, hay dc phm;

2- Th gii hn dung mi nhm 1 v dung mi nhm 2 khi chng tn ti trong dc cht, t dc, hay dc phm;

3- nh lng dung mi nhm 2 khi lng tn d ln hn 1000 phn triu (0,1 %) hoc nh lng dung mi nhm 3 tn d khi c yu cu.

Cc dung mi tn d nhm 1, nhm 2, nhm 3 c lit k ti cc bng trong Ph lc 10.14.1 Quy nh v dung mi tn d trong thuc Vit Nam.

Chuyn lun ny gii thiu 3 cch pha mu th v cc diu kin k thut tim pha hi cc mu th ha hi ln h thng sc k kh. S dng hai h sc k, h sc k A thng c chn trc, cn h sc k B thng c dng cng c kt qu pht hin. Vic chn cch pha mu th ty thuc vo s ha tan ca mu th. Trong mt s t trng hp cch pha mu ty thuc dung mi tn d cn kim tra.

Cc dung mi tn d sau y khng c pht hin d dng bng cc diu kin tim pha hi ghi trong chuyn lun ny: Formamid, 2-ethoxyethanol, 2-methoxyethanol, ethylen glycol, N-methylpyrrolidon v sulfolan. Phi p dng cc qui trnh khc thch hp kim tra s tn d ca cc dung mi trn.

Khi dng qui trnh ca chuyn lun ny nh lng cc dung mi tn d, phi tin hnh thm nh qui trnh.

 

Tin hnh

Thc nghim bng phng php sc k kh (Ph lc 5.2) vi k thut tim pha hi p tnh.

 

Pha mu th

Cch 1 : Dng kim tra dung mi tn d trong cc cht tan trong nc

Dung dch th (1): Ha tan 0,200 g mu th trong nc, pha long vi nc ti 20 ml.

Cch 2 : Dng kim tra dung mi tn d trong cc cht khng tan trong nc.

Dung dch th (2): Ha tan 0,200 g mu th trong N,N-dimethylformamid (DMF), pha long ti 20 ml vi cng dung mi.

Cch 3 : Dng kim tra N,N-dimethylacetamid v/hoc N,N- dimethylformamid khi bit r hoc nghi ng c mt hoc c hai dung mi ny tn d trong mu th.

Dung dch th (3): Ha tan 0,200 g mu th trong1,3-dimethyl-2- imidazolidinon (DMI) v pha long n 20,0 ml vi cng dung mi.

Khi khng c cch pha mu no nu trn ph hp vi mu th, th cch pha mu th v iu kin pha hi p tnh p dng phi c chng minh l ph hp.

Dung dch dung mi (a): Ha tan 1,0 ml dung dch i chiu dung mi tn d nhm 1 vi nc thnh 100 ml. Pha long 1,0 ml dung dch ny vi nc ti 10,0 ml.

Dung dch dung mi (b): Ha tan mt lng thch hp dung mi tn d nhm 2 trong dimethylsulfoxid. Pha long vi nc ti 100 ml. Tip tc pha long thu dc dung dch c nng bng 1/20 gii hn quy nh ti bng 10.14.2 trong Ph lc 10.14.1 Quy nh i vi tp cht l dung mi tn d.

Dung dch dung mi (c): Ha tan 1,00 g dung mi hoc cc dung mi c trong mu th vi dimethylsulfoxid hoc nc (nu thch hp), v pha long vi nc ti 100 ml. Tip tc pha long thu c dung dch c nng bng 1/20 gii hn quy nh ti Bng 10.14.1.1 hoc Bng 10.14.1.2. trong Ph lc 10.14.1 Qui nh i vi tp cht l dung mi tn d.

Dung dch mu trng: Chun b nh cch pha dung dch dung mi (c) nhng khng thm dung mi cn xc nh ( kim tra s vng mt ca cc pic nhiu).

Dung dch th: Ly 5,0 ml dung dch th v 1,0 ml dung dch mu trng cho vo mt l tim.

Dung dch i chiu (a) (nhm 1): Ly 1,0 ml dung dch dung mi (a) v 5,0 ml cht pha long thch hp vo mt l tim.

Dung dch i chiu (a1) (nhm 1): Ly 1,0 ml dung dch dung mi (a) v 5,0 ml dung dch th vo mt l tim.

Dung dch i chiu (b) (nhm 2): Ly 1,0 ml dung dch dung mi (b) v 5,0 ml cht pha long thch hp vo mt l tim.

Dung dch i chiu (c) 1 ml dung dch dung mi (c) v 5 ml dung dch mu th vo mt l tim.

Dung dch i chiu (d): 1,0 ml dung dch mu trng v 5,0 ml cht pha long thch hp vo mt l tim.

ng kn cc l tim ni trn bng nt cao su c bao lp polytetrafluoroethylen v gi bi mt vng chp ngoi bng nhm. Lc mnh c mt dung dch ng nht.

 

Cc iu kin tim pha hi p tnh c th dng:

 

Thng s hot ng

Cch pha mu

1

2

3

Nhit cn bng (o C)

80

105

80

Thi gian cn bng (pht)

60

45

45

Nhit dng chy (o C)

85

110

115

Kh mang

Nitrogen hoc heli dng cho sc k kh p sut thch hp

Thi gian iu p (giy)

30

30

30

Th tch tim ((ml)

1

1

1

 

iu kin sc k

H thng A

Ct mao qun thu tinh hoc ct c nng rng di 30 m, ng knh trong 0,32 mm hoc 0,53 mm c ph bng lp cc polymer lin kt mng gm polydimethylsiloxan 94% v polycyanopropylphenylsiloxan 6% (dy 1,8 mm hoc 3,0 mm).

Kh mang: Nitrogen dng cho sc k kh hoc heli dng cho sc k kh., t l chia dng: 1:5, tc dng khong 35 cm/giy.

Detector ion ha ngn la (c th dng detector khi ph hoc pht hin dung mi tn d nhm 1 dng hp cht clorid c th dng detector thu (bt) in t).

Duy tr nhit ct 40 oC, trong 20 pht, sau gia tng nhit vi tc 10oC/pht cho n khi t 240 oC, gi 240 oC trong 20 pht. Nhit bung tim 140 oC, nhit detector 250 oC.

H thng B

Ct mao qun thu tinh hoc ct c nng rng di 30 m c ng knh trong 0,32 mm hoc 0,53 mm, c ph macrogol 20.000 dy 0,25 mm.

Kh mang: Nitrogen dng cho sc k kh hoc heli dng cho sc k kh, t l chia dng: 1:5, tc dng khong 35 cm/giy.

Detector ion ha ngn la (c th dng detector khi ph hoc pht hin dung mi tn d nhm 1 dng hp cht clorid c th dng detector thu (bt) in t.

Duy tr nhit ct 50 oC trong 20 pht, sau gia tng nhit vi tc 6 oC/pht cho n khi t 165 oC. Gi 165 oC trong 20 pht. Nhit bung tim 140 oC, nhit detector 250 oC.

Phn tch trn h thng A

Tim 1 ml pha hi ca dung dch i chiu (a ), ghi sc k cc iu kin sao cho c th xc nh c t l tn hiu/nhiu ca 1,1,1-tricloroethan. T l tn hiu/nhiu ca 1,1,1-tricloroethan khng c nh hn 5; xem sc k ti Hnh 10.14-1.

Tim 1 ml pha hi ca dung dch i chiu (a1). Pic ca cc dung mi nhm 1 thng c pht hin.

Tim 1 ml pha hi ca dung dch i chiu (b), ghi sc k cc iu kin sao cho h s phn gii gia acetonitril v methylen clorid c th xc nh c. H thng sc k A s thch hp nu h s phn gii gia acetonitril v methylen clorid khng nh hn 1,0 v sc k c dng nh hnh 10.14-2.

Tim 1 ml pha hi ca dung dch th ln ct phn tch ca h A. Nu sc k thu c khng c pic no tng ng vi mt trong cc pic ca nhng dung mi tn d trong sc k cho bi cc dung dch i chiu (a) v (b) th mu th t yu cu. Nu sc k ca mu th c pic tng ng vi pic ca mt trong nhng dung mi tn d trong sc k cho bi cc dung dch i chiu (a) v (b), th phi tip tc phn tch trn h B.

Phn tch trn h thng B

Tim 1 ml pha hi ca dung dch i chiu (a) ghi sc k cc iu kin sao cho c th xc nh c t l tn hiu/nhiu ca benzen. T l tn hiu/nhiu ca benzen khng c nh hn 5. Xem sc k ti hnh 10.14-3.

Tim 1 ml pha hi ca dung dch i chiu (a1). nh ca cc dung mi nhm 1 thng c pht hin.

Tim 1 ml pha hi ca dung dch i chiu (b), ghi sc k cc iu kin sao cho h s phn gii gia gia acetonitril v tricloroethylen c th xc nh c. H thng sc k B s thch hp nu h s phn gii gia acetonitril v tricloroethylen khng nh hn 1,0 v sc k c dng nh hnh 10.14-4.

Tim 1 ml pha hi ca dung dch th. Nu sc k thu c khng c nh no tng ng vi mt trong cc nh ca dung mi tn d trong sc k cho bi cc dung dch i chiu (a) v (b) th mu th t yu cu. Nu sc k ca mu th c nh tng ng vi mt trong nhng nh ca dung mi tn d trong sc k cho bi cc dung dch i chiu (a) v (b) v ph hp vi kt qu phn tch trn h thng A th tin hnh nh sau:

Tim 1 ml pha hi ca dung dch i chiu (c) ln ct phn tch ca h thng A hoc B. iu chnh nhy ca h thng sao cho chiu cao ca pic dung mi tn d (hay ca cc dung mi tn d) khng di 50% ton thang chiu cao trn my ghi.

Tim 1 ml pha hi ca dung dch i chiu (d) ln ct. Phi khng c nh nhiu no c pht hin. Tim 1,0 ml pha hi ca dung dch th v 1,0 ml pha hi ca dung dch i chiu (c) ln ct. Tim lp li 2 ln na.

Din tch pic trung bnh ca dung mi tn d trong sc k cho bi dung dch th khng c ln hn mt na (1/2) din tch trung bnh ca pic tng ng trong sc k cho bi dung dch i chiu (c). Th nghim ch c gi tr nu lch chun tng i ca cc gi tr khc bit (cc hiu s) gia ba cp din tch pic ca dung dch th v dung dch i chiu (c) nh hn 15 %.

Khi hm lng dung mi tn d thuc nhm 2 hoc nhm 3 mc 0,1% hoc ln hn th c th tin hnh nh lng bng phng php cng thm cht chun vo mu th.

 

 

 


Hnh10.14-1: Sc k cc dung mi nhm 1 phn tch trn h thng A theo qui trnh 1; detector ion ha ngn la.

4: benzen; 10: carbon tetrachlorid; 14: 1,2-dicloroethan; 15: 1,1-dicloroethylen; 52: 1,1,1-tricloroethan.

 

 

 

 


 

 

Hnh10.14-2: Sc k cc dung mi nhm 2 phn tch trn h thng A theo qui trnh 1; detector ion ha ngn la.

3: acetonitril; 11: cloroform; 13: cyclohexan; 16a: cis-1,2-dicloroethylen; 17: dicloromethan; 29: hexan; 30: 2-hexanon; 34: methanol; 49: pyridin; 51: toluen; 53: 1,1,2-tricloroethylen; 54: xylen (ortho, meta, para); 58: clorobenzen; 61: tetralin; 62: methylcyclohexan; 63: nitromethan; 64: 1,2-dimethoxyethan.

 

 

 

 

 

 

 

 


 

Hnh 10.14-3 : Sac ky o cc dung moi nhom 1 phan tch tren he thong B theo qui trnh 1; Detector ion hoa ngon la.

4: benzen; 10: carbon tetraclorid; 14: 1,2-dicloroethan; 15: 1,1-dicloroethylen; 52: 1,1,1-tricloroethan.

 

 

 

 

 

 

 

 

 

 

 

 

 


 

Hnh10.14-4: Sc k cc dung mi nhm 2, phn tch trn h thng B theo qui trnh 1; detector ion ha ngn la.

3: acetonitril; 11: cloroform; 13: cyclohexan; 16a: cis-1,2-dichloroethylen; 17: dicloromethan; 23: 1,4-dioxan; 29: hexan; 30: 2-hexanon; 34: methanol; 49: pyridin; 51: toluen; 53: 1,1,2-tricloroethylen; 54: xylen (ortho, meta, para); 58: clorobenzen; 61: tetralin; 62: methylcyclohexan; 63: nitromethan; 64: 1,2-dimethoxyethan.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Hnh 10.14 -5: S cc bc tin hnh

 

Dung dch th