Effect of Surface Phenomena on Selective Separation Properties of Liquid Crystal Stationary Phase
The present work deals with the study on the distribution of contribution of adsorption and dissolution to retention volume of individual components in gas-liquid chromatography as dependent on the amount of liquid crystal stationary phase deposited on solid support and on the chromatographic column...
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| Cite this: | Effect of Surface Phenomena on Selective Separation Properties of Liquid Crystal Stationary Phase / M. Dzagania, L. Eprikashvili, M. Zautashvili, N. Pirtskhalava, I. Rubashvili // Хімія, фізика та технологія поверхні. — 2010. — Т. 1, № 3. — С. 248-250. — Бібліогр.: 8 назв. — англ. |
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| author | Dzagania, M. Eprikashvili, L. Zautashvili, M. Pirtskhalava, N. Rubashvili, I. |
| author_facet | Dzagania, M. Eprikashvili, L. Zautashvili, M. Pirtskhalava, N. Rubashvili, I. |
| citation_txt | Effect of Surface Phenomena on Selective Separation Properties of Liquid Crystal Stationary Phase / M. Dzagania, L. Eprikashvili, M. Zautashvili, N. Pirtskhalava, I. Rubashvili // Хімія, фізика та технологія поверхні. — 2010. — Т. 1, № 3. — С. 248-250. — Бібліогр.: 8 назв. — англ. |
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| description | The present work deals with the study on the distribution of contribution of adsorption and dissolution to retention volume of individual components in gas-liquid chromatography as dependent on the amount of liquid crystal stationary phase deposited on solid support and on the chromatographic column temperature.
Досліджено розподіл внесків адсорбції і розчинення в утримуваний об'єм окремих компонентів у газорідинної хроматографії в залежності від кількості нанесеної на твердий носій рідкокристалічною нерухомої фази і температури нагріву хроматографічної колонки.
Исследовано распределение вкладов адсорбции и растворения в удерживаемый объём отдельных компонентов в газо-жидкостной хроматографии в зависимости от количества нанесенной на твердый носитель жидкокристаллической неподвижной фазы и температуры нагрева хроматографической колонки.
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Хімія, фізика та технологія поверхні. 2010. Т. 1. № 3. С. 248–250
_____________________________________________________________________________________________
248 ХФТП 2010. Т. 1. № 3
UDC 543.544
EFFECT OF SURFACE PHENOMENA ON SELECTIVE
SEPARATION PROPERTIES OF LIQUID CRYSTAL
STATIONARY PHASE
M. Dzagania, L. Eprikashvili, M. Zautashvili, N. Pirtskhalava, I. Rubashvili
Melikishvili Institute of Physical and Organic Chemistry of Georgia
5 Jikia Street, Tbilisi 0186, Georgia, physorgchem@pochta.ru
The present work deals with the study on the distribution of contribution of adsorption and dissolution to
retention volume of individual components in gas-liquid chromatography as dependent on the amount of
liquid crystal stationary phase deposited on solid support and on the chromatographic column temperature.
INTRODUCTION
Liquid crystalline compounds have been
known for nearly 120 years but the beginning of
their use in gas chromatography can be attributed
to 60–70-s of the last century [1, 2]. These com-
pounds are distinguished by their properties. Due
to melting of solid crystals, the liquid is formed in
which molecules are located not only in parallel
to each other but in the layers (smectic phase) and
under further heating another liquid form is cre-
ated in which molecules are arranged in parallel
while layers are not formed (nematic phase). Fur-
ther increase in temperature leads to a definite
point of orientation loss and the liquid becomes
isotropic [3]. Most frequently such mesophases
are observed in aromatic compounds containing
benzene and naphthalene rings. Namely the pre-
sence of these phases makes the especially selec-
tive with respect to linear molecules. Quantitative
factor of the separation ability of these stationary
phases is the maximum structural selectivity
(MS) which is defined as the ratio of the volume
retention of para- and meta-xylene. As a rule, the
maximum structural selectivity appears at the
temperatures close to the lower limit of presence
of the nematic mesophase [4]. Smectic and
nematic mesophases are used primarily for sepa-
ration of isomeric alkyl and halogen substituted
benzene derivatives, phenols, polycyclic aromatic
compounds [1–3]. When transiting from liquid
crystals to the isotropic liquid state, they lose
their selectivity with respect to linear molecules
and the sequence of elution of individual compo-
nents in most cases is defined by their boiling
points. The efficiency of stationary liquid phases
in gas chromatography depends greatly on their
proper application on the surface of solid media,
i.e. in the creation of a uniform liquid layer in the
separation column which would screen negative
impact of active adsorption centers of a nozzle as
completely as possible. At the same time, it should
be noted that in some cases the contribution of ad-
sorption of the tested substance on the surface of
stationary liquid-solid support is most significant
for some systems ranging from several percent to
tens percents of total retention [5]. Contribution of
adsorption process to chromatography is signifi-
cant even at high impregnation of solid carriers by
stationary liquid [6]. All this as a whole lowers
selectively-isolation effect of stationary fluid,
worsening the maintenance and resolution ability
of the chromatographic column.
EXPERIMENTAL
The present study aimed to determine the na-
ture of distribution of contribution of adsorption
and dissolution to retention volumes of definite
components in gas-liquid chromatography de-
pending on the amount of applied liquid crystal
stationary liquid on solid support and the tem-
perature of the chromatographic column. The ob-
ject of the study was a liquid crystal, stationary
liquid hydroquinone-bis-(p-heptyloxybenzoate)
characterized by nematic mesophase within
120–195°C, with the polarity of 37% [4], dis-
solved in isopropylbenzene [7] which was ap-
plied respectively in the amounts 5, 8, 10, 15%
on the Chromaton N-AW solid support of
0.250–0.315 mm graining. Application of station-
ary liquid on the solid support was carried out
according to the technique most widely used in
the practice of gas chromatography [8].
Effect of Surface Phenomena on Selective Separation Properties of Liquid Crystal Stationary Phase
_____________________________________________________________________________________________
ХФТП 2010. Т. 1. № 3 249
As test compounds, we used triads of iso-
mers: ortho-, meta-, para-xylene and ortho-,
meta-, para-cresol. Contributions of adsorption
and dissolution to the retention volumes of some
sorbates in the process of chromatography were
determined at the column temperature of 100°C
(when stationary phase is a solid crystal) and
160°C (when stationary liquid is characterized by
the presence of mesophase).
Experiment was conducted on a Chrom-5
chromatograph. Length of the column – 3 m,
diameter – 3 mm. Detector FID, carrier gas –
helium, flow rate of carrier gas – 30 ml/min. Con-
tributions of dissolution and adsorption at the in-
terface between stationary liquid-solid support to
the retention of the above organic compounds
were determined by the formula [6]
Vg
T= Γ /ρ+ Γ Γ3S3
.100/П
where VgT – specific retention volume (cm3); g –
mass of the liquid phase (g); Г – Henry coeffi-
cient; ρ – density of the stationary liquid (g/cm3);
Γ3 – adsorption coefficient at the interface be-
tween a stationary phase-solid support (cm); S3 –
the value of the surface of solid medium (cm2 /g);
П – degree of saturation (rate of impregnation, %)
of solid carrier by stationary liquid.
The first part of the equation describes the
contribution of dissolution (R), and the second is
the contribution of adsorption (A) to the retention
of the studied organic compounds. Graphics asso-
ciating values VgT and 100/P were used for de-
termination of the Γ/ρ value.
RESULTS AND DISCUSSION
The information on the distribution of contri-
bution of dissolution and adsorption at the elution
of the above mentioned organic compounds from
the chromatographic column are summarized in
Tables 1 and 2.
The data presented in Table 1, where the
chromatography is carried out at the column tem-
perature of 100°C prove that the share of adsorp-
tion interaction in the process of retention of in-
vestigated compounds is high and that at the in-
crease of degree of impregnation of the solid sup-
port of the stationary liquid, this factor increases.
This fact cannot be explained to the end currently,
although it can be assumed that at the column
temperature of 100°C liquid phase is crystallized
in the form of individual solid units concentrating
in the form of separate "islands" in the accessible
pores or on the active centers of the solid support
Table 1. Distribution of contributions of adsorption
(A) and dissolution (D) in % LC deposited
on solid support Chromaton
N-AW.(tcol.=100°C)
Rate of impregnation, %
5 8 10 15
Sor-
bate
D A D A D A D A
o-
xylene
54.5 45.5 42.4 57.6 22.5 77.5 19.6 80.4
m-
xylene 53.5 47.5 41.9 58.1 21.0 79.0 16.4 83.6
p-
xylene 52.3 47.7 39.7 60.3 21.1 78.9 16.8 83.2
o-
cresol
55.1 44.9 30.3 69.7 22.5 77.5 22.1 77.9
m-
cresol 55.4 44.6 31.3 68.7 22.6 77.4 22.4 77.6
p-
cresol 54.9 45.1 29.8 70.2 21.7 78.3 20.9 79.1
Table 2. Distribution of contributions of adsorption (A)
and dissolution (D) in % LC deposited on solid
support Сhromaton N-AW (Tcol. – 160°C)
Rate of impregnation, %
5 8 10 15
Sor-
bate
D A D A D A D A
p-
xylene 30.1 69.9 42.3 57.7 47.3 52.7 47.8 52.2
m-
xylene 32.4 67.6 45.3 54.7 51.3 48.7 52.6 47.4
o-
xylene 34.1 65.9 48.9 51.1 53.8 46.2 54.7 45.3
о-
cresol 40.3 59.7 52.2 47.8 58.4 41.6 60.1 39.9
m-
cresol 43.7 56.3 55.7 44.3 60.7 39.3 62.2 37.8
p-
cresol
44.9 55.1 57.3 42.7 62.1 37.9 63.4 36.6
while the remaining (greater) part of the surface
nozzles is in the "bare" state. With the increase of
a degree of saturation in this temperature interval
majority of dissolved crystals separates from the
solvent, having no time for fixing on the surface
of solid medium and are washed out of the co-
lumn. As a whole, the effect of elevation of the
role of adsorption interactions is exposed equally
for xylenes and for cresols.
Table 2 presents the results characterizing the
distribution of above interaction in the process of
chromatography of the some organic compounds
at the stationary phase at the column temperature
of 160°C, i.e. when the crystals are in the state of
nematic mesophases.
This case shows also, though to a lesser
extent, the effect of adsorption interaction
M. Dzagania, L. Eprikashvili, M. Zautashvili et al.
_____________________________________________________________________________________________
250 ХФТП 2010. Т. 1. № 3
which is expected to decrease with the in-
crease in the degree of impregnation of solid
support by stationary liquid. The contribution
of dissolution to retention of cresols in the
process of chromatography is slightly higher
than that for xylenes. Apparently, under such
temperature conditions, stationary liquid is
capable to create more homogeneous film on
the surface of solid media on a certain part of
the surface of solid support.
CONCLUSIONS
Thus, the above stationary phase in the
heating mode of the column of 160°C cannot
be used for separation of the triad xylene iso-
mers because of the small difference in reten-
tion values of these components, although the
sequence of their elution is characteristic of
liquid crystals in the nematic phase: a meta-
ortho-para. As to the triad of cresol isomers,
this phase allows their separation at high-
resolution rate, with the criteria of uniformity
∆=0.71 [6] with the order of elution that is
characteristic of a liquid crystal in the nematic
mesophase.
REFERENCES
1. Vigdergauz M.S., Vigalok R.V., Dmitrie-
va G.V Chromatography in system gas-liquid
crystal // Uspekhi Khimii – 1981. – V. 50,
N 5, P. 943–972. (in Russian).
2. Andronikashvili T.G., Arustamova A.G., Sul-
tanov N.T., Markarian K.P. Liquid Crystals
in Capillary Chromatography. – Tbilisi:
Metsniereba, 1983. – 98 p. (in Russian).
3. Guide to Gas Chromatography / Ed.
E. Leibnitz, H.H. Shtruppen. – Moscow: Mir,
1988. – V. 2. – 508 р. (in Russian).
4. Kotsev N. Handbook for Gas Chromatography. –
Moscow: Mir, 1976. – 200 р. (in Russian).
5. Berezkin V.G., Pakhomov V.P., Sakodynsky K.I.
Solid Supports in Gas Chromatography. – Mos-
cow: Khimiya, 1975. – 200 р. (in Russian).
6. Vigdergauz M.S. Calculations in Gas Chro-
matography. – Moscow: Khimiya, 1978. –
247 p. (in Russian).
7. Dzagania M.A. Influence of solid carrier in
the chromatographic properties of liquid crys-
tal stationary phase: Ph.D (Chem.) thesis. –
Tbilisi, Georgia, 1998. – 34 p.
8. Sakodynsky K.I., Brajnikov V.V., Volkov S.A.
et al. Analytical Chromatography. – Moscow:
Khimiya, 1993. – 464p. (in Russian).
Received 18.05.2010, accepted 17.08.2010
Вплив поверхневих явищ на селективно-розділові властивості
рідкокристалічної нерухомої фази
М.А. Дзаганія, Л.Г. Епрікашвілі, М.Г. Зауташвілі, Н.В. Пірцхалава, І.М. Рубашвілі
Інститут фізичної та органічної хімії ім. П. Мелікішвілі
вул. Джикія 5, Тбілісі 0186, Грузія, physorgchem@pochta.ru
Досліджено розподіл внесків адсорбції і розчинення в утримуваний об'єм окремих компонентів у газо-
рідинної хроматографії в залежності від кількості нанесеної на твердий носій рідкокристалічною нерухомої
фази і температури нагріву хроматографічної колонки.
Влияние поверхностных явлений на селективно-разделительные свойства
жидкокристаллической неподвижной фазы
М.А. Дзагания, Л.Г. Эприкашвили, М.Г. Зауташвили, Н.В. Пирцхалава, И.М. Рубашвили
Институт физической и органической химии им. П. Меликишвили
ул. Джикия 5, Тбилиси 0186, Грузия, physorgchem@pochta.ru
Исследовано распределение вкладов адсорбции и растворения в удерживаемый объём отдельных компо-
нентов в газо-жидкостной хроматографии в зависимости от количества нанесенной на твердый носитель
жидкокристаллической неподвижной фазы и температуры нагрева хроматографической колонки.
|
| id | nasplib_isofts_kiev_ua-123456789-28986 |
| institution | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| issn | 2079-1704 |
| language | English |
| last_indexed | 2025-11-25T23:50:36Z |
| publishDate | 2010 |
| publisher | Інститут хімії поверхні ім. О.О. Чуйка НАН України |
| record_format | dspace |
| spelling | Dzagania, M. Eprikashvili, L. Zautashvili, M. Pirtskhalava, N. Rubashvili, I. 2011-11-27T16:14:26Z 2011-11-27T16:14:26Z 2010 Effect of Surface Phenomena on Selective Separation Properties of Liquid Crystal Stationary Phase / M. Dzagania, L. Eprikashvili, M. Zautashvili, N. Pirtskhalava, I. Rubashvili // Хімія, фізика та технологія поверхні. — 2010. — Т. 1, № 3. — С. 248-250. — Бібліогр.: 8 назв. — англ. 2079-1704 https://nasplib.isofts.kiev.ua/handle/123456789/28986 543.544 The present work deals with the study on the distribution of contribution of adsorption and dissolution to retention volume of individual components in gas-liquid chromatography as dependent on the amount of liquid crystal stationary phase deposited on solid support and on the chromatographic column temperature. Досліджено розподіл внесків адсорбції і розчинення в утримуваний об'єм окремих компонентів у газорідинної хроматографії в залежності від кількості нанесеної на твердий носій рідкокристалічною нерухомої фази і температури нагріву хроматографічної колонки. Исследовано распределение вкладов адсорбции и растворения в удерживаемый объём отдельных компонентов в газо-жидкостной хроматографии в зависимости от количества нанесенной на твердый носитель жидкокристаллической неподвижной фазы и температуры нагрева хроматографической колонки. en Інститут хімії поверхні ім. О.О. Чуйка НАН України Хімія, фізика та технологія поверхні Теорія хімічної будови, реакційної здатності та хімічного модифікування поверхні твердих тіл Effect of Surface Phenomena on Selective Separation Properties of Liquid Crystal Stationary Phase Вплив поверхневих явищ на селективно-розділові властивості рідкокристалічної нерухомої фази Влияние поверхностных явлений на селективно-разделительные свойства жидкокристаллической неподвижной фазы Article published earlier |
| spellingShingle | Effect of Surface Phenomena on Selective Separation Properties of Liquid Crystal Stationary Phase Dzagania, M. Eprikashvili, L. Zautashvili, M. Pirtskhalava, N. Rubashvili, I. Теорія хімічної будови, реакційної здатності та хімічного модифікування поверхні твердих тіл |
| title | Effect of Surface Phenomena on Selective Separation Properties of Liquid Crystal Stationary Phase |
| title_alt | Вплив поверхневих явищ на селективно-розділові властивості рідкокристалічної нерухомої фази Влияние поверхностных явлений на селективно-разделительные свойства жидкокристаллической неподвижной фазы |
| title_full | Effect of Surface Phenomena on Selective Separation Properties of Liquid Crystal Stationary Phase |
| title_fullStr | Effect of Surface Phenomena on Selective Separation Properties of Liquid Crystal Stationary Phase |
| title_full_unstemmed | Effect of Surface Phenomena on Selective Separation Properties of Liquid Crystal Stationary Phase |
| title_short | Effect of Surface Phenomena on Selective Separation Properties of Liquid Crystal Stationary Phase |
| title_sort | effect of surface phenomena on selective separation properties of liquid crystal stationary phase |
| topic | Теорія хімічної будови, реакційної здатності та хімічного модифікування поверхні твердих тіл |
| topic_facet | Теорія хімічної будови, реакційної здатності та хімічного модифікування поверхні твердих тіл |
| url | https://nasplib.isofts.kiev.ua/handle/123456789/28986 |
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