Adsorption of some vitamins onto highly disperse silica surface
Adsorption of thiamine (vitamin Bi), riboflavin (B2), and pyridoxine (B6) from aqueous solution onto amorphous silica surface was studied. The investigation of adsorption of tocopherol (vitamin E) and its short-chained analogues from hexane and aqueous micellar solution was performed. Some data on m...
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| Datum: | 2001 |
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Chuiko Institute of Surface Chemistry National Academy of Sciences of Ukraine
2001
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| author | Vlasova, N. N. Golovkova, L. P. Svezhentsova, A. A. Chuiko, A. A. |
| author_facet | Vlasova, N. N. Golovkova, L. P. Svezhentsova, A. A. Chuiko, A. A. |
| author_institution_txt_mv | [
{
"author": "N. N. Vlasova",
"institution": "Інститут хімії поверхні НАН України"
},
{
"author": "L. P. Golovkova",
"institution": "Інститут хімії поверхні НАН України"
},
{
"author": "A. A. Svezhentsova",
"institution": "Інститут хімії поверхні НАН України"
},
{
"author": "A. A. Chuiko",
"institution": "Інститут хімії поверхні НАН України"
}
] |
| author_sort | Vlasova, N. N. |
| baseUrl_str | |
| collection | OJS |
| datestamp_date | 2018-11-27T09:42:39Z |
| description | Adsorption of thiamine (vitamin Bi), riboflavin (B2), and pyridoxine (B6) from aqueous solution onto amorphous silica surface was studied. The investigation of adsorption of tocopherol (vitamin E) and its short-chained analogues from hexane and aqueous micellar solution was performed. Some data on mechanism of vitamin adsorption and structure of adsorption layer were obtained by electron spectroscopy and mass-spectrometry. |
| first_indexed | 2025-07-22T19:30:04Z |
| format | Article |
| fulltext |
ADsoRPTIoГ{oFsoNIЕVITAMINSoIчToнIGHLY
DIsPЕRsЕ SILICA SURFAсЕ
N.N. Vlasova, L.P. Golovkova, A'A' Svezhentsova' and A'A' Chuiko
Institutе of Suфсе Сhеmisф, Nаtionаl Аcаdеmу of Sсienсеs
Gеn. Nаumo,,i. l1i,, kуiv- t 6 a, 0 3 ] 6 1, UKRАINЕ, е -mаil : v|аbаrs@i. com,uа
Abstrасt
Adsoгptionofthiaminе(vitaminBr),гiboflaйn(в',andpyridoxinе(86)fromaqueous
so1ution onto amoгphous siliсa suгfacе *u, ,'ujiй. Thе invеstigation of adsorption of
toсophегol (йtamin вj ."j ri'
'ьort-оhainеd
ana1og,.еs from heхanе and aqueous miсеllar
solution was pегfoгm.с*i"'Ъ с"ta on mеchйsm"of vitamin adsoгption and struсturе of
adsoгptionlaуеrwегеobtainеdbуеleсtronspесtrosсoруandmass-spесtrometry.
Praсtiсalappliсationofsiliсеoussoгbеntsinmеdiсinеintheсapaсityof
еntегosoгbentsposеs"""'ь.'ofquеstions,withoneofthеmostгеlеvantandsегious
bеingthеquestion*n..,ningadsoгption'ofvitaminsondispегsеsiliсas.Vitamins
nесеssary foг сells to pегfoЫ lь."i'^ ч'1?l funсtions arе not synthеsized in a human
organism and must b. J;;li; *ith food. Thеrеforе, if a givеn йtamin is еffiсiеntly bound
to siliсa' prеsсription oi Ъiti.u..ontaining .йo,oib.nts- may lеad to defiсienсу of thе
vitamin in an oгganism, and the oгganism by itsеlf is not ablе to make up for thе dеfiсienсy.
Thus, when taking .u.h u soгbent Ьu.,
"
long pеriod
.of
timе, оnе should eхегt сontгol over
thе lеvеl of thе vitarш;l;;i;
";g.nism
and й Ъ"'. of nееd fil' for a dеfiсiеnсy.
on thе ",ь.,
iu"с' *.lk biou,,imilation of fat - solublе йtamins ffi::
..::Y:]
pгoblеmofсгеationn.*'"al.atfoгmofsuсhsubstanсеs.Usingtheadsorbentsasсaгrlеr
for bad.soluble vitamins it,s possiblе to сгеaie tь. n.:
'"iL:|
drugs. Suсh foгms of
grugs, in addition ,o-uа*.p'ion of toхiс substanсеs from oгganism, may bе used as a
rеsегvr fat solublе and poor assimilatе иtuыn'. onе of thе йеthods of inоrеasing of
biologiсal aссessibilitу of fat-solublе uitamins is appliсation of suгГaсtants proйding
solubilization of poor solublе substanс., in *ui.,, and.carriеs with dеvеlopеd suгfaсe for
following adsoгption of foгmеd miсеllеs.
First, bу *.;;Г;;;plе, сonsidег adsoгption of thiaminе (Br). Thiamine is a
сomponеnt of thiaminе dipьЬ.pr,ui.' tt is a сoen.,fmе of a sеriеs of еnzymes that сatalyzе
dесarboxуlatronofсr-kеtoaсidsanddeсompositiono|сr;o1vkеtonеs.Bеsidеs'itеxегtsan
еffесt on protеin, fat, and carbohуd.ratе mеtaйolism [1] A low сontent of йtamin Br in an
organism.uу.uu,.anumbегofdiseasеs,яrstoг.ыtdiseasеsofnегvoussystеm.A
сomplеtе dеfiсiеnсу oi ui,u*n Br in food ieads to a sеvеrе aйtaminosis and to suсh a
sеriоus disеasе as bегi-bегi'
/-s
//-s
H,N\ нzс_ш\
-i
n'**._*,Ё"*.*o"
\-1 6"ц",*,o* ,Д\ '!// \\ | wг2v| 2v' ' N, ) Hзi
{/ \)H.i \ /\/tNtsNj'. !/\HrC
пзU H
T*
HT2*
368
Ё|
^{
,us
lns
4lt
nd
'hе
,.,
us
of
оf
.^lJdl
iе;
of
;a
no,..э
Гoг
ia
'zе
Wе сaггiеd out thе dеtailеd studiеs of thе thiamine
siliсa from aquеous solutions. [2-a]. Thiaminе dibгomidе
aquеous solution undeгgoеs еleсtrolytiс dissoсiation and,
singlе. and doublе.сhargеd сations'
The dеpеndеnсе of thе peгсentage
of thеsе foгms on pH of solutions as wеll as
adsoгption of thiaminе as a funсtion of pH
aгe illustratеd in Fig 1. In aсidiс solutions at
pН 2_з thе adsorption of thiaminе is
insignifiсаnt, but with inсгeasing pH it
rapidly inсrеasеs. Thе absеnсе of adsoгption
of thiamine сations in aсidiс solutions, i.е.
undеr сonditiоns сlosе to the zеro.сharge
point ofthе siliсa suгГaсе, providеs еvidеnсe
fbr thе prеsеnсе of a substantial
сontгibution of iоn.ion intеraсtions to the
adsoгption. This assumption is сoгroboгatеd
by thе data сollесtеd thгough ехpегimеnts
оn dеsoгption of thе edsorbed thiamine into
an еlесtгolytе solution (0'I M NaCl). Thе
availabilitу of sodium ions to make the
dеsorption moге dееp ргoved such
mесhanism of adsoгption .
adsorption on hiфly dispeгse
(offiсial prеpaгation) in an
dеpеnding on pH, ехists as
Fig.l Distгibution diagгam of thiaminе in
solution and adsoгption of thiaminе onto
siliсa A-300 as a funсtion of pH
(Cт: 1 mМ, C5;92 =8 gЛ).
4lt
en
.-\
lд
Thе adsoгption isothегm at pН 1 2 (undег thеse сonditions all thе thiaminе is in thе
foгm of singlе-сhaгgеd сation) is satisfaсtoгi.ly dеsсгibеd by the Langmuiг еquation. Thе
сalсulatеd сonstant of adsorption еquilibrium, K,, is equal to (l.97t0.30)хl0a Umol, thе
maximum adsoгption valuе, 4., amounts to 54t3 рmoyg.
Some data about thе mесhanism of thе thiaminе adsoгption and about thе struсtuге
of adsoгption layегs havе bееn gаtheгеd through сompaгativе studiеs of еlесtroniс speсtra
of thiamine in сrystals, in solutions, and in thе сasе of its adsoгption on Sioz [3] as well as
through mass speсtrosсopiс invеstigations of thе thегmolysis of fтее and adsorbеd tЫamine
14] Thе mass speсtrosсopy has shown that immobilization of thiamine involvеs
paгtiсipation of еnd hydroryl groups of its molесules and is aссompaniеd with formation of
ioniс hуdгogеn bonds bеtwееn сations of thiamine and dissoсiatеd silanol groups of thе
siliсa suгfaсе. The studies of the еlесtroniс speсtгa havе геvеalеd сhingеi in thе
сonfoгmation of a thiaminе molесule upon its adsoгption, namely: as a геsult of thе aсtion
of adsoгption foгсеs thе foldеd сonfoгmation of a thiaminе molесulе in solutions [5]
сhangеs into a planaг сonfiguгation on thе Sio2 suгГaсe, whiсh sеems to be faсi]itatеd Ъy
bonding ofеnd hydroxyl groups ofthiaminе to the suгfaсe.
Riboflavin (RF) is a сomponent of a large numbеr of flavoprotеins i.е. еnzymеs
whiсh сatalyzе numеrous rеaсtions in an organism [6]. Bidzilya еt аl. [1] havе studiеd
adsoгption of гiboflavin on a highly dispeгsе siliсa from aquеous solutions undeг statiс
сonditions Thе сonсеntгation of riboflavin in initial and еquilibrium solutions was
dеtегmined by a spесtrophotometriс tеchnique. It has bееn found that the adsoгption value
oГRF, in сontrast to thiaminе, deсгeases with inсrеasing pн (1 . l0) (Ftg2) This faсt is
еxplainеd in tеrms of the aсid-basе propeгtiеs of RF and silanol gгoups of the soгbеnt
suгfaсe and rеaсtions that may proсееd on this suгfaсe.
з69
',?,,."xo-')зCHzoH
,. ^/(сHoH)зcH2oHt1)V-l
o
(l)
(2)
(3)
(4)
Rеaсtions (1)' (з)' and (4) imp1y foгmation
of hуdгogеn bonds bеtwееn silanol groups
of thе suгfaсе and molеclrles of RF. The
сontгibution of геaоtion (2) to the
adsoгption sееms to Ье insignifiсant bесause
aftег addition of riboflavin to thе siliсa
suspеnsion that was allowеd to stay foг
sеvеral hours anу deсгеase in pH of thе
sоlution was not obsеrvеd. it is also evidеnt
that thе dесгеasе in thе adsoгption valuе
with inсгeasing pLI of thе solution from 4 to
7 (i е in thе rangе whеrе thе сonсеntгation
of dissoсiatеd silanol gгoups on thе surfaсe
inсгеasеs) permits us to assumе that thе
сontributiоn of гeaсtion (4) to thе
adsoгption should also be гelativеlу small.
pl-l
Fig 2. Distгibution diagram of гiboflavin in
solution and pH-dеpеndеnсе of riboflavin
adsoгptiоn onto siliсa A-300 (Cц = 0.7 пtМ,
Csroz = 10 gl).
"'YY*Y*Y. "'YY*Y'Y.
н.e,М'^Y'n н,с,М'a*'
RFH:- RFH
From thе dереndеnсе of thе pегсеnt сontеnt of aсidiс-basiс foгms of RF on pH (Fig.2) it is
sееn that in thе intегval 1 < pH < 3 thе pгеdominant form of riboflavin in thе solution is its
protonatеd positively сhaгgеd foгm RFH2*, whilе at pH > 5 its nеutral form RFH. It
follows that thе гeaсtions whiсh may proсeеd on the adsorbеnt surfaсе in an aсidiс mеdium
сan bе rеprеsеntеd bу еquations (1) and (2), whеrеas in subaсidiс and neutral mеdia by
еquations (3) and (a)'
=SioH + RFНz- <э =SioH...RFHz*
=SioH + RFН2* <э =Sio--RFHz* + FГ
=SiOH + RFH <+ =SiOH"'RFH
=Sio. +RFH е =Sio-...RF-H
Vitamin Bо is a mеmbег of thе family of thгее intегсonveгtiblе сompounds, namelу
pyгidoхinе, pyridoxal, and pyгidoхaminе [8]. Tissuеs of plants сontain mainlу pyгidoxinе.
Vitamin B6 pгеsеnt in tissuеs of animals and in animal produсts is pгеdominantly in thе
fbrm of pyridoxal, pyгidoxamine, and thеiг phosphates Phosphoriс еster of thе aldehydе
form of Bс (pугidoхal' P4) is an еssеntialсomponеnt of a numbег of еnzуmеs thatcatalуze
tгansformations of amino aсids and aminеs. Pyгidoхinе is a standaгd foгm of vitamin Bo
offеrеd foг salе' In aquеous solutiоns pуridoxine maу еxist in sеveгal forms aссoгding to
thе sсhemе of acid-basе еquilibгia :
З70
HOH2C
PNF{-
11\-
HoH2с
PN'
Figuгe З illustгatеs регcеntagе of aсidiс and basiс foгms of pyгidoхinе as a funсtion
эf pH. In aсidiс solutions pугidoхinе is in its pгotonated foгm PN}Г. As pН inсгeasеs,
thеге appeaгs a dеpгotonatеd foгm that еxists as two tautomегs, namеly bipolaг ion PМ
md neutгal molесulе pьР. tn aqueous solutions the еquilibгium is shiftеd towards thе
эipolaг ions, while in alсoholiс solutions towards thе nеutгal molесule [s]. In alkaline
solutions pyгidoхinе is pгеsent in thе foгm of anion PNt.
PNO
:-i :TS
:T.
{'.:.тl
Nt
I
I
ll.:'
]ш
lшt.
We сollесtеd геlevant infoгmation
about thе adsoгption of pyridoхinе from
aqueous solutions on a highly dispеrsе siliсa
t9] Thе adsoгption in statiс сonditions,
with thе сonсеntгation of vaгious aсidiс and
basiс forms of pyridoхinе bеing dеtегminеd
bу a spесtгophotomеtгiс tесhnique was
studiеd. ouг prеliminary studiеs allowed us
to find that tautomег P},f pгaсtiсatly was
not adsorbеd fгom aquеous solutions.
Depеndenсе of thе pyridoхinе adsoгption
valuе in thе сasе of solutions with
pyгidoхinе сonсеntгation of 0.2 and 0 8
mМ is displayеd in Fig. 3. As a гesult of thе
сonsidегation of possible гeaсtions on thе
siliса surfaсе with allowanсе for thе
сoгrеsponding acid.basе еquilibria wе
advanсеd thе following sсhеme of
adsoгption interaсtion at vaгious pH.
Fig. 3 Distгibution diagram of pyгidoxinе in
solution and pH-dеpendеnсе of pyгidoxine
adsoгption onto siliсa A-з00 (Cp : 0.2 and
0.8 mМ, Csioz = 8 g/l).
!пк
h:
h
р
р,
h,,
Р
I
A
з.7l
Thе adsoгption intегaсtion at pH < 3'5 was attгibutеd to linking of pyгidoxine
сations with nondissoсiatеd silanolgгoups thгough foгmation of hydrogеn bonds:
=SioH + PNH- е =SiOH.'.PNH* (5)
Thе inсrеasе in thе adsorption valuе obseгvеd in thе rangе of pH fгom 3.5 to 5.0 was
asсгibеd to thе appеaгanсе of bipolaг ions of pyгidoхinе in thе solution and foгmation of
complеxеs aссording to thе еquation
=SioH + P}f <э =Sio-_PN}Г (6)
In сomplianсe with this еquation the pгoсеss involvеs tгansfеr of a pгoton from silanol
gгoups of siliсa to ory-gеn atom of pyгidoхinе. Thе сomplеx foгmed is stabilizеd oйng to
ion-ion interaсtions among its spесiеs' In spitе of thе fuгthег inсгеasing in the
сonсеntгation of bipolar ions in solutions, in the гangе of pH from 5 to "| the adsoгption
valuе does not inсrеasе, whiсh may bе гelatеd to pгoсeеding of rеaсtions aссording to
еquations (7) and (8):
:sioH + PN= <э =Sio-_P]f + H-
=Sio- + PМ <э =Sio_-PМ
The сomplех foгmеd in сonfoгmity to thеsе еquations sееms to bе сhaгaсtегized by a low
stability beсausе of thе mutual геpulsion of its two nеgativе сhaгgеs. At higheг valuеs of
pН in thе solution thеге appеaг anions of pyridoxinе, whiсh hindeгs its intеraсtion with thе
suгГaсе whosе numbег of nеgativеly сharged sitеs beсomеs moгe large.
Thе adsoгption isotheгms сonstructеd for сations and bipolaг ions of pyridoхinе aге
obtainеd ' Thе maximum adsoгption valuе foг bipolar ions сalсulatеd fтom thе Langmuiг
еquation ( 35 mmoVg) is appгoхimatеlу by an oгdег of magnitude grеatег than foг сations
of pyгidoхinе (1.2 mmoUg).
Thе rеfleсtion spесtra гесoгded for pyridoxinе adsorbеd fтom acidiс and neutral
solutions pгovidе an indiгесt сoпoboration of thе abovе.mеntionеd assumptions about thе
сhaгaсtеr of thе adsoгption pгoсеssеs proсееding in this systеm. In thе spесtra foг both
samplеs thеге is an intеnse band attгibuted to pгotonatеd pyridoxinе, PNH*, and thеre is
pгaсtiсally no band that сould bе assignеd to bipolar ions, PЬ]*. Consеquently, pyгidoхine
in both samplеs is in the protonatеd foгm.
Fat-solublе vitamins, inсluding с-toсophеrol, are known to possess antioхidant
pгopeгtiеs so that vitamins of this tуpе show the сapability foг inhibiting oхidation of lipids.
Thеsе сharaсtегistiсs make it possible to usе thеm in mеdiсine as гadioprotесtors and as
agents for trеatmеnt foг somе tumoгal disеasеs' But, unfoгtunatеly, suсh vitamins are
inсonvenient for appliсation and storage (they aге rеadily oхidizеd undeг the aсtion of UV
radiation). With a viеw to put powdеrlikе fat.solublе vitamins into a more manageable
loose foгm immunе to oxidation, a study Il0] was madе of adsorption of йtamin Е and of
its two shoгt-chainеd analoguеs (II) and (III) whiсh also possеssed antioxidant propeгtiеs.
I : R=CtlзCo; R1=[CН2C[I2с}I(CI]3)Cн2]3н
II : R=CH3CO; R1 =CН2Cll=с(сH3)Cн3
III: R=Н; Rr=Н
CH2R1
Тhе сontеnt of thе vitamin and its analoguеs on thе soгbеnt suгfaсе was dеterminеd
by a speсtгophotomеtгiс techniquе in tегms of thе diffегenсе in thеiг сonсеntratioпs in
З72
{7)
(8)
l-пз
solutions bеforе and aftеr thе adsoгption. Thе .spесtгal сharaсtеristiсs оf thе pгepaгations
arе summarizеd in Тablе.
Тablе
Spесtгal сharaсtеristiсs ofс-toсophегol and its analoguеs and paгamеtегs ofthеir
adsoгption fгom hехanе on a highly dispегsе siliсa
Suгfaсe сovегagep.l
nm'
Г.)'€Kp
Nm
Compound
I 284.4 2230
II 281.7 2690
III 297.6 3500
Iv 284.4 2з50
2',7t 0.996 0,90-1.22
424 0.992 0.90-1.10
з'15
298
) 11
з.l6
50-66
76 - 100
59'7 0.997 0.80 100
86 0.994 0.90-1.22 15 -21
No|аtioп. ,l. absoгption band
of adsoгption; .1Ъ: maхimum
molесulе'
maхimum; e еxtinсtion сoeffiсient; K,: еquilibrium сonstant
adsoгption; p; сoгrеlation сoefiiсiеnt; S: area oссupied by a
Thе isothегms of thе adsoгption of pгеpaгations I _ IiI and phaгmaсeutiсal
pгеparation of йtamin Е (5 % solution of с'-toсophегol aсеtatе in oil) fгom hехanе fall into
a сlass of thе Langmuiг isothегms. The maximum adsoгption values and adsoгption
еquilibrium сonstants aге listеd in Тablе . From thе collесted data it is sееn that with
dесrеasing of thе sidе сhain lеngth thе maхimum adsoгption valuе inсгeasеs' Thе maximum
adsorption valuе of thе offiсinal pгеpaгation is substantially loweг than that of puге
сr-toсophегol' whiсh may bе геlatеd to thе сompeting adsoгption of thе oil (сomponеnt of
thе prеpaгation) on thе adsoгbеnt suгfaсe. The moге high adsorption valuеs obsеrvеd foг
the short.сhained analogues of vitamins Е arе due to thеiг lowег hydгophobiс pгopепies in
сomparison йth toсophегol and, subsequеntly, to thеir lowег affinity for the solvеnt
(hехanе) and to thеiг highег affinity for thе hydгophiliс siliсa suгfaсe. Thе highеst affinity
foг thе siliоa suгfaсе is сharaсtегistiс of pгepaгation III whosе сhгoman ring сontains a
hydгoхyl group and not an aсеtate gгoup. on thе basis of thеsе data wе made an
assumption that thе adsoгption of с-toсophегol and its analoguеs on the siliсa suгfaсе
pгoсeeds mainly thгough hydrogen bonds bеtwееn silanol gгoups of thе surfaсе and
oхygеn atoms ofсhroman гings and aсеtatе or hydroхyl gгoups [10]
Тhе maximum adsoгption valuеs madе it also possiblе to сalсulatе aгеas oссupiеd
by adsoгbatе molесules on thе siliсa suгfaсе (sеe Tablе) Thе сompaгativе study of сr-
toсophегol and its analoguеs involvеd сonstruсtion of modеls of molесulеs foг thе
сompounds in quеstion, as well as еstimation of the arеa of thеiг ргojесtion on a horizontal
planе at vaгious oriеntations of thе molесulеs with геsресt to this plane (сhroman ring lies
flat on thе suгfaсe and hydroхyliс гadicals of сompounds I and II еither liе flat on thе
suгГaсе oг aге oriеntеd outwaгds)' Thе projесtion aгеa еstimatеs madе in this way also aгe
listеd in Тablе. Thе suгfaсе сovеragе еqual to |00 % is attainеd only upon thе adsoгption
оf shoп.сhainеd analoре III. As геgaгds adsoгption of сompound II, thе hundгed.pег-сent
suгfaсе сovегage would bе pоssible only if both сhгoman гings and hydгoxyliс гadiсals lay
flat on thе siliсa suгГaсе. In thе сasе of adsoгption of сr.toсopherol from hexane the
maхimum suгГaсе сovегagе dеpends on thе oгiеntation of its molеоulеs and amouпts to
only 50 %.
^лd'
finally, upon adsoгption of thе offiсinal pгеpaгation orr.ly 1 5 _ 20 Yo of the
suгfaсе сan bе сovегеd with molесulеs of с-toсophегol.
31з
Fuгthег, it has bееn shoц'n that thе adsorрtion-dеsorption сuгvеs гесordеd for
toсophегol aсеtatе сomplеtеlу сoiпсidе, i е' thе adsогрtiсln is геvегsiblе. Тhе spесtгa takеn
foг thе solutions obtainеd aftеr thе dеsorption oГ соmроunds I - iII сomplеtеly pгеsегvr
thе shapе and positions of absoгption bands Uрon stoгing rhе prерaгatiоns in thе opеn air
at гoom tеmpегatuге foг 3 months in thе spесtra for thе dеsoгbеd сompоunds therе appеar
nо additional bands, whiсh givеs еr,idеnсе for thе faсt that thе adsoгbеd pгеpaгations aге
геsistant to oхidation'
Тhе assimilabilitу of с,-toсophегol as 'леil as of othеr fat-solublе vitamins in thе
gastгointestinal tгaсt is insufiiсiеnt' onе of thе methods to makе fat-solublе substanсes
moге геadilу availablе to a living огgaпism сonsists in appliсation of suгfaсe aсtive
substanсes (SAs) that inсrеasе watег solubility of slightly solublе substanсеs. Wе havе
studiеd solubilization of toсophеrois I - III in aqueous solutions of nonioniс SAS Twеen
80 [l1]. Thе ехaminatioп oГthе absorрtion spесtгa for toсophегols in aquеous miсеllaг
solutions of Twееn 80 madе it рossiblе to еstablish that сompounds I and II arе solubilized
through insегtion into miсеllaе of Twееn 80, with thеir loсi being hуdгophobiс nuсlеi of
miсеllaе. Compound III is solubilizеd both through insегtion into miсеllaе and through
foгmation of assoсiatеs of molесulеs of сompound III with molесulеs of Twееn 80. Тhе
loсi of molесulеs of сompound III in thе сasе of both thе insепion and foгmation of
assoсiatеs is thе polyoхуеthуlenе shеath of molесulеs of Twееn 80.
Toсophегols I _ IIi arе еffесtivelу adsoгbed on the suгfaсe of a highlу disperse
siliсa fгom aquеous rniсеllar solutions of Twееn 80 [12,1з] At сonсеntгations ovеr thе
сгitiсal miсеlla сonсеntration (с.m с.) thе adsorption of Twееn 80 itsеlf does not dеpеnd on
thе pгеsеnсе of toсophеrоls in solutiоn The adsoгption isothегms гeсoгdеd foг Twеen 80
and toсophегois aге satisfaсtoпly linеaгizеd ln thе Langmuiг сo.oгdinatеs' Thе maхimum
adsoгption values сalсulatеd foг сompоunds I _ III arе pгaсtiсallу idеntiсal (0.l82 _ 0.l89
mmoVg)' Fгom thе data gathеrеd onе сan еstimatе thе solubility valuеs foг toсophеrols in
an adsorption layег and in еquilibгium solutions (at an initial гatio solubilizatе:SAS of
about 0.34)' In thе сasе of toсopheгol l thе solubility valuе in an еquilibrium solution and
on thе suгfaсе aге approximatеlу idеntiсal and equal to thе limit of solubilization of
сompound I in aquеous miсеllar solutiоn. It impliеs that thе toсophеrol molесules foцnd in
a adsorption laуеr геmain to bе loсalizеd within miсеllaе oГ Twееn 80. As геgards
toсophегols II and IiI, thе valuеs of thеiг solubility in an adsorption layег arе highег than
those iп solution, whiсh providеs еvidеnсе for ехсеss adsorption. Thе absеnсe of any
ехсess adsoгption of toсopheгоl i is ехplained bу thе availability of long hydгoсarboniс
гadiсals in thе molесulеs, whiсh givеs risе to a high affinity oГ сompound I for thе inneг
hуdrophobiс sphегеs of Twееn 80 miсеllaе and a lowег affinitу foг thе hydгophiliс suгfaсe
of siliсa' Wе assumed thаt thе adsoгption ot toсophегol II may bе сaused bу migration of
some рaгt of solubilizеd molесulеs from miсellaе to thе adsorbеnt suгfaсe, whilе
adsoгption of toсophеrol III maу bе thought of as adsoгptiоn both of fтee molесules that
arе not bound in пriсеllaе and of a fraсtion of Гoгmегlу solubilizеd molесules that lеavе the
miсеla shеath and pass to the adsoгbеnt suгГaсе [12,l3]. Thе validitу of thе assumptions is
сoпoboгatеd by the data gatheгеd from thе геflесtion sресtra геоoгded for adsorbed
samplеs.
Rеferеnсеs
l. Меtzlег DЕ. Bioсhеmistry. Thе Сhеmiсal Rеaсtions of Living Cells. N.Y., San
Franсisсo, London: Aсadеmiс Pгеss' l977. - |296 p.
2. Adsorbtion of thiaminе onto highlу dispегsе siliсa/ N.N. Vlasova, N.K. Davidеnko,
N.М' Shеvсhеnko, V,I. Bogomaz' A.A'Сhuiko llIJkr. Сhim. Zh' _ 1991. .v.57, N 12.
. P .121.7 -L28О.
эlч
3. Еleсtгoniо spесtra and сonfoгmation of thiаrnine adsoгbеd onto highly disperse siliсa/
N.N. Иasova' N.K' Davidеnko, V.I. Bogomaz A.A.Chuiko// Ukr. Сhim. Zh.-|992-
V.58, N 8.-P.621.62з,
4. The mass-speсtгosсopiо invеstigation of thегmolysis of thiamine in frеe statе and
adsoгbеd on thе highly dispersе siliса suгfaсе / V.A.Pokгovskii, N.N,Vlasova,
N.K.Davidеnko, T.V.Kulik llUkг. Chim. Zh.-1993-v.59, N 12, - P |z57-|260,
5. Yu.М. ostrovskii Aсtivе Sites and Gгoupings in thе Thiaminе Мolесulе' Мinsk: Nauka
i Tеkhnika. 19.7 5. 424 p.(in Russian)
6. Lehningег A.L Biochеmistry' N.-Y.: Woпh Publishегs |nc. |9.|2. 957 p.
7. Adsorbtion of Ribophlavin and its Coppеr Complеx onto Highly Dispеrsеd Silica
SuгГaсе/V.A. Bidzilya, L.P. Golovkova, N.N,Vlasova' V.I. BogomazJlZh.Fiz. Khim. _
1998' - V.72' N з. - P'51,/-520'
8. Yu.V. Мorozov, N N. Bazhulina, Еlесtroniс Struсtuге, Spеctrosсopу, and Rеaсtivity of
Мolесules. М':Nauka. l988. 288 p. (in Russian).
9. Adsoгbtion of vitamin Bь onto highlу dispегsе siliса/ A.A. Svеzhеntsova,
N'K. Davidenko, N,N. Иasova, V.I. BogomazJl Zh. Fiz. Khim -1993 . У.6,I, N 6 -.
P.1242-t245
l0.Adsorbtion of сr-tokophezol and its analoguеs onto siliсa suгfaсе/ V.A. Bidzilуa,
L.P. Golovkova' N.N. Vlasova, N.K. Davidеnko// tjkr. Khim. Zhuгn' -1994 - V.60,
N 9. - P.616-619.
11'.Solubilization of с-tokophеzol and its analoguеs in aquеous solution of nonioniс
suгГaсtant /V.A' Bidzilya, L.P. Golovkova, N'N. Viasova, V.I. Bogomaz // Kolloidn.
Zhurn. - 1'995. -У'52, N 2. - P.1',7з-175.
l2 Adsoгbtion of с-tokophеzol and its analogues onto a highly dispегse siliсa suгГaсе
from aquеous miсеllaг solution of nonioniс suгГaсtant /V A Bidzilya' L.P. Gоlovkova,
N.N. Vlasova, V.I Bogomaz ll Zhuгn. Fiz. Khim -1'996'. V 70, N 2 - P.290-з01.
l3.Solubilization and adsoгption of shoгt сhain analoguе of vitamin Е in pгеsеnсе of
nonioniс s suгfaсtant /L.P' Golovkova, V.A. Bidzilya, N.N. Vlasova, V.I. Bogomaz //
Zhuгn. Fiz. Khim. _l995. - v.б9. N 6. - P l06l-l064.
з15
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| id | oai:ojs.pkp.sfu.ca:article-74 |
| institution | Surface |
| keywords_txt_mv | keywords |
| language | English |
| last_indexed | 2025-07-22T19:30:04Z |
| publishDate | 2001 |
| publisher | Chuiko Institute of Surface Chemistry National Academy of Sciences of Ukraine |
| record_format | ojs |
| resource_txt_mv | surfacezbircomua/a7/e35c2cfb529a67d85444750d6201dfa7.pdf |
| spelling | oai:ojs.pkp.sfu.ca:article-742018-11-27T09:42:39Z Adsorption of some vitamins onto highly disperse silica surface Adsorption of some vitamins onto highly disperse silica surface Adsorption of some vitamins onto highly disperse silica surface Vlasova, N. N. Golovkova, L. P. Svezhentsova, A. A. Chuiko, A. A. Adsorption of thiamine (vitamin Bi), riboflavin (B2), and pyridoxine (B6) from aqueous solution onto amorphous silica surface was studied. The investigation of adsorption of tocopherol (vitamin E) and its short-chained analogues from hexane and aqueous micellar solution was performed. Some data on mechanism of vitamin adsorption and structure of adsorption layer were obtained by electron spectroscopy and mass-spectrometry. Adsorption of thiamine (vitamin Bi), riboflavin (B2), and pyridoxine (B6) from aqueous solution onto amorphous silica surface was studied. The investigation of adsorption of tocopherol (vitamin E) and its short-chained analogues from hexane and aqueous micellar solution was performed. Some data on mechanism of vitamin adsorption and structure of adsorption layer were obtained by electron spectroscopy and mass-spectrometry. Adsorption of thiamine (vitamin Bi), riboflavin (B2), and pyridoxine (B6) from aqueous solution onto amorphous silica surface was studied. The investigation of adsorption of tocopherol (vitamin E) and its short-chained analogues from hexane and aqueous micellar solution was performed. Some data on mechanism of vitamin adsorption and structure of adsorption layer were obtained by electron spectroscopy and mass-spectrometry. Chuiko Institute of Surface Chemistry National Academy of Sciences of Ukraine 2001-06-10 Article Article application/pdf https://surfacezbir.com.ua/index.php/surface/article/view/74 Surface; No. 4-6 (2001): Chemistry, Physics and Technology of Surface; 368-375 Поверхность; № 4-6 (2001): Химия, физика и технология поверхности; 368-375 Поверхня; № 4-6 (2001): Хімія, фізика та технологія поверхні; 368-375 3154-8091 3154-8083 en https://surfacezbir.com.ua/index.php/surface/article/view/74/73 Авторське право (c) 2001 N.N. Vlasova, L.P. Golovkova, A.A. Svezhentsova, A.A. Chuiko |
| spellingShingle | Vlasova, N. N. Golovkova, L. P. Svezhentsova, A. A. Chuiko, A. A. Adsorption of some vitamins onto highly disperse silica surface |
| title | Adsorption of some vitamins onto highly disperse silica surface |
| title_alt | Adsorption of some vitamins onto highly disperse silica surface Adsorption of some vitamins onto highly disperse silica surface |
| title_full | Adsorption of some vitamins onto highly disperse silica surface |
| title_fullStr | Adsorption of some vitamins onto highly disperse silica surface |
| title_full_unstemmed | Adsorption of some vitamins onto highly disperse silica surface |
| title_short | Adsorption of some vitamins onto highly disperse silica surface |
| title_sort | adsorption of some vitamins onto highly disperse silica surface |
| url | https://surfacezbir.com.ua/index.php/surface/article/view/74 |
| work_keys_str_mv | AT vlasovann adsorptionofsomevitaminsontohighlydispersesilicasurface AT golovkovalp adsorptionofsomevitaminsontohighlydispersesilicasurface AT svezhentsovaaa adsorptionofsomevitaminsontohighlydispersesilicasurface AT chuikoaa adsorptionofsomevitaminsontohighlydispersesilicasurface |