High temperature stationary phase of polysiloxane containing N,N′-bis(diphenylsilyl) tetramethylcyclodisilazane for gas chromatography

Article abstract of DOI:10.1039/c4ra17152g

An alternate copolymer (P(BPTMC)-alt-ODMS) constructed from N,N′-bis(diphenyl-silyl) tetramethylcyclodisilazane (BPTMC) and oligo-dimethylsiloxane (ODMS) segments was synthesized and coated on the inside of fused-silica capillary columns to evaluate their

Full text of DOI:10.1039/c4ra17152g

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High temperature stationary phase of polysiloxane
containing N,N0-bis(diphenylsilyl)
tetramethylcyclodisilazane for gas
chromatography
Cite this: RSC Adv., 2015, 5, 22399
*
Pengchao Zhao, Yanyan Niu, Miao Yu, Na Niu, Huan Wang, Xinxin He and Bo Wu
An
alternate
copolymer
(P(BPTMC)-alt-ODMS)
constructed
from
N,N0-bis(diphenyl-silyl)
tetramethylcyclodisilazane (BPTMC) and oligo-dimethylsiloxane (ODMS) segments was synthesized and
coated on the inside of fused-silica capillary columns to evaluate their properties as stationary phase in gas
chromatography. The thermal stability, selectivity, column efficiency, and working range of these capillary
columns were characterized. The obtained results indicated that such produced columns exhibited better
separation efficiency than commercial ones with high thermal stability and low column bleeding. The upper
working temperature can reach up to 400 ꢀC, which resulted in high-quality GC analysis of polyethylene
pyrolysis products, petroleum, and aromatic hydrocarbon mixtures. The influence of BPTMC content on the
thermal stability and polarity of the stationary phase was also investigated.
Received 28th December 2014
Accepted 12th February 2015
DOI: 10.1039/c4ra17152g
www.rsc.org/advances
Recent years, some new materials as GC stationary phases
with high thermal and mechanical stability have been reported,
Introduction
especially for carbon nanotubes (CNTs) and metal–organic
frameworks (MOFs). In 2005, Mitra reported the rst applica-
tion of self-assembled CNTs in long capillary tubes used for gas
chromatography columns.16 Later, through catalytic chemical
vapor deposition process, they synthesized the self-assembled,
single-walled carbon nanotubes and used it as high tempera-
ture stationary phases with no column bleed or other instability
at temperatures around 425 ꢀC.17 In 2010, Yan group fabricated
the rst MOF-coated capillary column (MIL-101) as stationary
phase for high-resolution capillary GC separation and achieved
a baseline separation of p-xylene, o-xylene, m-xylene, and
ethylbenzene within 1.6 min.18 Then Yan group focused on the
molecular sieving effect of MOFs (ZIF-7, ZIF-8,19 and UIO-66
(ref. 20)) with different pore window size and pore size. With
High-temperature gas chromatography (HTGC) is suitable for
analyzing high molecular weights with thermal stability and
high efficiency.1 The most important component of such a GC
instrument is the chromatographic column, the heart of which
is a stationary phase that determines the thermal stability and
selectivity of the GC capillary column. A stationary phase with
high thermal stability is required to obtain high column
temperature. Considering these motivations, modied poly-
siloxanes, including poly-m-carborane-siloxane (Dexsil series)
and silphenylene-modied polysiloxane, which are obtained by
replacement of the oxygen atoms of the backbones using ary-
lene (–C6H4–)2–4 and carborane (–CB10H10C–),1,5–8 have been
adopted as high temperature stationary phases (HTSP) for
several decades.9–14 These two types of stationary phases are
commonly used as HTSP in GC.1ꢀ5 Despite withstanding
ꢀ
ꢀ
narrow pore windows (ꢁ3.4 A) and larger pores (ꢁ11.4 A),
zeolitic imidazolate framework-8 (ZIF-8) demonstrates a high
capability in sieving linear alkanes from branched alkanes and
offers high resolution GC separation of linear alkanes from each
other according to boiling points.19
temperatures of up to 400 C to 480 C,1 the Dexsil series pol-
ꢀ
ysiloxanes are only applied to separate non-polar and weakly
polar substances.2,3 In addition, the decaborane used for
fabricating the Dexsil series is highly toxic. Regarding
silphenylene-modied polysiloxane, which has higher polarity
than poly-m-carborane-siloxane because of the introduction of a
phenyl group, the maximum opꢀerating temperature can only be
Cyclodisilazane, a compound with relatively high polarity,
was synthesized by Fink and exhibited good thermal stability,
with a decomposition temperature up to 500 ꢀC.21 Breed
prepared an oligomer of cyclodisilazane and siloxane,22 and the
resulting decomposition temperature was still above 450 ꢀC.
Notably, a series of alternate copolymers synthesized by Xie's
group using hydroxyl cyclodisilazane and a,u-diethylin (or
dimethylamino) dimethyl polysiloxane presented good thermal
endurance and good solubility in organic solvents such as
controlled in the range of 380 C to 400 C.15 Therefore, fabri-
ꢀ
cating a stationary phase with both high thermal stability and
polarity is signicant.
School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250100,
P. R. China. E-mail: wubo@sdu.edu.cn
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toluene.23–26 Meanwhile, P(BPTMC)-alt-ODMS (an alternate
Polyethylene pyrolysis products as chromatographic separa-
copolymer constructed by N,N0-bis(diphenyl-silyl) tetrame- tion sample were prepared as follows: 100 g polyethylene was
thylcyclodisilazane (BPTMC) and oligo-dimethylsiloxane placed into a 500 mL round bottom ask with air condenser
(ODMS) segments) has been found to show good lming under N2 protection. Aer heating to 600 ꢀC to 650 ꢀC, the C–C
ability as a commercial stationary phase, exhibiting almost the bonds in alkyl chains were broken randomly, and the products
same temperature tolerance as m-carborane-siloxane,27,28 were collected. Aer 30 min, approximately 85 g of product was
making it suitable to act as stationary phase in HTGC. However, obtained.
to the best of our knowledge, the use of P(BPTMC)-alt-ODMS as
GC stationary phase has not been reported yet. No similar copolymer were analyzed by H NMR and FT-IR spectroscopic
commercial stationary phase has also been reported. methods. The molecular weight and distribution were deter-
The chemical structure and composition of the synthesized
1
In addition, compared to the above high temperature mined and calculated against the polystyrene standard by gel
stationary phases, such as Dexsil series, silphenylene-modied permeation chromatography (Waters 515 HPLC) at room
polysiloxane, and silylphenylene ether-modied polysiloxane, temperature. Toluene was used as eluent at a ow rate of 0.35
the polysilazane studied in this paper has a novel structure. It is mL minꢂ1. The glass transition temperature of the copolymer
characterized in that: (1). rigid block unit (N,N0-bis(diphenyl- was measured using differential scanning calorimetry (Pyris 7,
silyl) tetramethylcyclodisilazane) has
a rational structure: Perkin-Elmer Instruments, Norwalk, CT). Elemental analysis
volume of constitutional unit of cyclodisilazane is smaller than was performed by a Vario EI III elemental analyzer (Elementar,
that of carborane, but four phenyl groups on it play an impor- Germany).
tant role in increasing polarity of a stationary phase while it can
be inferred that its CP index is higher than Dexsil-300; plus, its
Synthesis of P(BPTMC)-alt-ODMS stationary phase and
characterization
volume and rigidity exceed those of silylphenylene and silyl-
phenylene ether, making for increase in temperature resistance
performance; (2). the degree of polymerization of siloxane
oligomer is three, thus cyclization degradation of copolymer
can be effectively reduced. When the siloxane polymerization
degree is four or above, the temperature resistance performance
of stationary phase will be weakened.
Based on these reasons, an alternate copolymer, P(BPTMC)-
alt-ODMS, has been synthesized and used as HTSP. Elemental
analysis, 1H nuclear magnetic resonance spectroscopy
(1HNMR), infrared spectroscopy (IR), and thermo-gravimetric
analysis (TGA) have been used to characterize the polymer
composition and structure. The coated fused silica capillary
columns with the polymer are evaluated on their selectivity,
polarity, inertness, separation efficiency, and bleeding. More-
over, the applications of such columns on the analysis of poly-
ethylene pyrolysis products, petroleum, and aromatic
hydrocarbon mixtures are described. The obtained results
reect a great potential of the P(BPTMC)-alt-ODMS in practical
applications, such as stationary phases for HTGC.
P(BPTMC)-alt-ODMS were prepared according to the procedures
described in Fig. 1.23,24 N,N0-Bis(chlorodimethylsilyl)-
tetramethylcyclodisilazane (II) was produced from hexame-
thylcyclotrisilazane (I) based on previously reported
methods.21,23 The reaction was conducted at 220 ꢀC using
compound I-to-dimethyldichlorosilane molar ratio of 1 : 1.8.
N,N0-Bis(chlorodiphenylsilyl) tetramethylcyclodisilazane (III)
was therefore synthesized from II,23 with a reaction temperature
of 320 ꢀC and molar ratio of II to diphenyldichlorosilane of
1 : 2.2. Aerward, a mixture of 10.9 g (0.02 mol) N,N0-bis(hy-
droxydiphenylsilyl) tetramethylcyclo-disilazane (IV) was
obtained from the hydrolysis of III, and 7.0 g (0.02 mol) a,u-
bis(diethylamino)-dimethylsiloxane (prepared according to
literature23,24) was stirred at 120 ꢀC under nitrogen for over 10 h.
Experiment
Regents and apparatus
Dimethyldichlorosilane, diphenyldichlorosilane, hexamethyl-
cyclotrisilazane, and diethylamine were all of analytical grade
and purchased from Beijing Chemical Works (Beijing, P. R.
China). 1,3-Dimethyl-1,1,3,3-tetraphenyl-disilazane (>99.5%) was
purchased from Shandong Kunrong Chemical Engineering
Company (Jinan, P. R. China). The test mixture for the polar
capillary column was prepared according to the method
described by Grob et al.29,30 Five Rohrschneider–McReynolds
standards (benzene, 2-pentanone, 1-nitropropane, 1-butanol,
and pyridine) were obtained from Fluka (Buchs, Switzerland).
Petroleum samples were obtained from Shengli Oil Field (Don-
gying, P. R. China). Polycyclic aromatic hydrocarbons were
prepared by mixing various chemically pure reagents together.
Fig. 1 Condensation reaction of cyclosilazane with polysiloxane to
obtain P(BPTMC)-alt-ODMS.
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When no Et2NH can be detected, the target polymers (V) were constants, divided by the sum of the Rohrschneider–McRey-
collected. Such products were dissolved in toluene and precip- nolds constants of OV-275 (4215), and multiplied by 100.8
itated with methanol of ve volume times. This procedure was
The upper working temperature was determined by evalu-
repeated for ve times to remove any small molecular polymer. ating the inertness and separation efficiency of the capillary
ꢀ
Aer evaporation of the solvent under vacuum, an opaque, column with the test mixtures aer conditioning up to 400 C.
white, highly viscous polymer with a yield of approximate 75% The capillary column (length, 30 m; i.d., 0.25 mm; and lm
was obtained. 1H NMR(CDCl3, 300 MHz, 25 ꢀC, d ppm): 0.137 [s, thickness, 0.31 mm) coated with Dexsil-300 (purchased from
18H, (CH3)6], 0.158 [s, 12H, (CH3)4], 7.374 to 7.560 [m, 20H, Ohio Valley Specialty Company, Marietta, Ohio, USA) was
(C6H5)4]; FT-IR (KBr, n/cmꢂ1): 3070.0 [n(Ar-H)], 1580.2, 1124.7 prepared using the same procedures.
[n(Ar-C]C)], 2961.7, 1428.9, 800.5 [n(C–H)], 1093.3 [n(Si–O–Si)],
1021.5, 842.2 [n(Si–N)]; Mn: 1.42 ꢃ 105, Mw/Mn: 1.98. Tg: ꢂ42.8
Results and discussion
Thermal stability of P(BPTMC)-alt-ODMS
ꢀC; elemental analysis (%), calculated (for C34H50Si7N2O4, %): C,
54.64; H, 6.74; N, 3.75. Found: C, 54.25; H, 6.82; N, 3.81.
Thermogravimetric analysis (TGA) was carried out to evaluate
the thermal stability of P(BPTMC)-alt-ODMS. The 10 mg sample
was heated from 40 ꢀC to 700 ꢀC at a rate of 10 ꢀC minꢂ1 under
helium. As shown ꢀin Fig. 2, the polymer started to decompose
with the literature.23 Such high thermal stability resulted from
the bulk unit of polymer constructed by the connection between
the rigid planar four-member ring structure of BPTMC and two
silicon atoms with two phenyls to form an organized copoly-
merized microstructure. The main chain had three dime-
thylpolysiloxane monomers. Steric hindrance would restrict the
formation of cyclic oligomers, and the rearrangement degra-
dation of polymer can only occur at high temperature.
Preparation of capillary column
The fused-silica capillary column (produced in our laboratory,
with a polyimide outside coating stable up to a high tempera-
ture of 420 ꢀC) was treated according to the procedures
described.4,10 The tubes with inner diameter of 0.25 mm were
lled with 10% (w/v) sodium hydroxide in ethanol solution, with
capillary length at 20 m to 30 m. The tubes were kept for 24 h
and consecutively rinsed with water, dilute hydrochloric acid
(1/3, v/v), water, and methanol (15 mL each). The tubes were
then dried under nitrogen at 250 ꢀC for 2 h. Aer washing with
1,3-dimethyl-1,1,3,3-tetraphenyl-disilazane in dichloromethane
(10%, w/v), the tubes were dried under nitrogen at room
temperature for 2 h to remove the residual solvent in the
column. Both ends of the capillary column were sealed and
ꢀ
slightly above 400 C and signicantly aer 480 C, consistent
Selectivity
ꢀ
deactivated at 420 C for 2 h. Aerward, the tubes were rinsed
The chromatogram of Grob reagents for our assembled capillary
column is shown in Fig. 3. The Grob test mixture was well-
separated and the peaks were nearly symmetrical, indicating
that P(BPTMC)-alt-ODMS possesses good coating property.
Compared with Dexsil-300 coated fused-silica capillary column,
P(BPTMC)-alt-ODMS coated ones can yield less tailing and
improved peak shapes.14
The elution order of analytes was consistent with that of OV-
17, except for am, which eluted aer E11, as shown in Fig. 3.30
This result indicates a similar retention capability to analytes
with 5 mL dichloromethane and dried under nitrogen at 250 ꢀC
for 2 h. The column was coated with a 0.5% (w/v) solution of the
P(BPTMC)-alt-ODMS in dichloromethane as stationary phase
with a lm thickness of 0.31 mm using a static coating method.
Finally, the capillary column was conditioned at 50 ꢀC for 0.5 h
under a ow of nitrogen, and the temperature was elevated to
400 C at a rate of 2 C minꢂ1 and maintained for 10 h.
ꢀ
ꢀ
Capillary evaluation
All analyses were performed on a Varian-3400 gas chromato-
graph (Varian company, USA) equipped with a ame ionization
detector (FID) and N2000 chromatographic data handing
system (Zhejiang University, Hangzhou, China). High purity
nitrogen (>99.999%) was used as carrier gas. The test mixtures
were introduced by capillary split injection at an injection split
ratio of 30 : 1. The split injector and detector working temper-
ꢀ
atures were 20 C higher than the nal column temperature.
ꢀ
Column efficiency was evaluated for naphthalene at 120 C
by the number of theoretical plates. The Kovats retention
indices of ve Rohrschneider–McReynolds standards (benzene,
2-pentanone, 1-nitropropane, 1-butanol, and pyridine) were
measured at 120 ꢀC. Stationary phase polarity was expressed by
Rohrschneider–McReynolds index, which was obtained from
the sum of the ve Rohrschneider–McReynolds constants
minus those from squalane.31,32 The average polarity of the
stationary phase was expressed as CP index, which was obtained
Fig. 2 TGA analysis for the P(BPTMC)-alt-ODMS. Temperature from
from the sum of the rst ve Rohrschneider–McReynolds 40 to 700 ꢀC at a heating rate of 10 ꢀC minꢂ1 under helium.
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copolymer5) which has a similar structure to P(BPTMC)-alt-
ODMS, have also been listed in Table 1.
Table 1 shows the middle polarity of P(BPTMC)-alt-ODMS
where the stationary phase is notably higher than that of Dexsil-
300, reecting a serious impact on the polarity by BPTMC units.
The overall polarity based on reference data is plotted against
the diphenyl content of dimethyl-diphenyl-polysiloxanes in Fig. 4,
where a nearly linear relationship can be observed. The graph and
the CP-index of P(BPTMC)-alt-ODMS show that the BPTMC units
displayed an average polarity corresponding to 25% diphenyl and
75% dimethyl-polysiloxane. The polarity of Dexsil-300, however,
only reached to the extent of 11% diphenyl and 89% dimethyl-
polysiloxy. From the structure of P(BPTMC)-alt-ODMS, the
content of BPTMC unit was measured to be about 25% in the
polymer, which means that a BPTMC unit acts like one with only a
single diphenylsiloxy group in chromatographic separation. In
fact, one BPTMC unit has two diphenylsiloxy groups. Therefore,
the diphenylsiloxy groups of the polymer have less effect on
chromatographic separation, which may be caused by the
considerable steric hindrance that prevents the interaction
between planar phenylene groups and analytes.
Fig.
3 Grob test chromatogram of P(BPTMC)-alt-ODMS coated
capillary column after thermal treatment at 400 ꢀC. Capillary length
30 m, film thickness 0.31 mm, i.d. 0.25 mm. Temperature program:
from 30 ꢀC (kept for 5 min), then to 240 ꢀC at 6 ꢀC minꢂ1. 10 cm sꢂ1
nitrogen linear velocity. Peaks: 1 ¼ 3-methylpentane (bp, 64 ꢀC), 2 ¼ n-
hexane (bp, 69 ꢀC), 3 ¼ methyl-cyclopentane (bp, 72 ꢀC), 4 ¼ chlo-
roform (bp, 61 ꢀC), D ¼ 2,3-butanediol, C10 ¼ decane, C11 ¼ undecane,
ol ¼ octanol, al ¼ nonanal, S ¼ 2-ethylhexanoic acid, P ¼ 2,6-dime-
thylphenol, A ¼ 2,6-dimethylaniline, am ¼ dicyclohexylamine, E10–E12
¼ methyl ester of decanoic, undecanoic, and dodecanoic acid.
Column efficiency
The separation efficiency of the P(BPTMC)-alt-ODMS column was
evaluated by the number of theoretical plates. The column had
4620 theoretical plates per m, which is a distinctly higher value
than that of the Dexsil-300 column (3465 plates per m). This result
indicates that the GC stationary phase using P(BPTMC)-alt-ODMS
between P(BPTMC)-alt-ODMS and OV-17. However, this elution
order is considerably different from that of Dexsil-300.14 The
tailing factor (TF) of ol with a relatively high peak is small and
equal to 1.16, which reects the lack of hydrogen bond forma-
tion between the H atom of ol and the N atom of BPTMC
because of the big steric effect of its nearly planar quadrilateral
structure. In other words, the rst class adsorption in the
chromatographic column is exceptionally weak.29 The small
peak height of al, however, denotes the existence of a second
class absorption of chromatographic column. Similar to
component A, S is also an acid that has a wider peak shape and
tailing, which should be attributed to overloading. The Trenn-
zahl (TZ) indexes of E10/E11 and E11/E12 are 23.8 and 21.6, with
an average of 22.7, disclosing that the chromatographic column
coated with P(BPTMC)-alt-ODMS has extremely high separation
efficiency.
Polarity
To investigate the general inuence of the BPTMC unit on the
polarity of the column, both the Rohrschneider–McReynolds
constant and the CP-index of P(BPTMC)-alt-ODMS have
been quantitatively measured, and the results are listed in
Table 1. For comparison, certain data related to Dexsil-300,
(34.5% bis(methylsiyl)-m-carborane, 65.5% dimethylsiloxane
Fig. 4 Plot of CP-index versus diphenyl content of dimethyl diphenyl-
polysiloxanes,10 and the equivalent diphenyl contents of P(BPTMC)-
alt-ODMS and Dexsil-300.
Table 1 Rohrschneider–McReynolds constants and the CP-index of P(BPTMC)-alt-ODMS and Dexsil-300
Benzene
n-Butanol
2-Pentanone
Nitropropane
Pyridine
Rohrschneider–McReynolds constant
CP-index
P(BPTMC)-alt-ODMS
Dexsil-300 (ref. 30)
72
47
97
80
119
103
178
148
165
96
631
474
15.0
11.3
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Table 2 Column bleed of P(BPTMC)-alt-ODMS and Dexsil-300 at
different temperatures
Relative bleeda (mV)
Stationary phases
360 ꢀC
380 ꢀ
C
400 ꢀ
C
P(BPTMC)-alt-ODMS
Dexsil-300
Empty capillary column
0.40
0.38
0.03
0.81
0.71
0.04
1.28
1.05
0.05
a
The relative column bleed (in mV) was the bleed at the nal
temperature minus the bleed at 60 ꢀC.10
has a good lm-forming property on the inner surface of fused
silica, as well as high separation efficiency.
Fig. 6 Chromatogram of petroleum components with P(BPTMC)-alt-
ODMS as stationary phase. Capillary length 30 m, film thickness 0.31
mm, i.d. 0.25 mm. Temperature program: from 50 ꢀC (kept for 5 min),
then to 400 ꢀC (kept for 5 min) at 6 ꢀC minꢂ1, 12 cm sꢂ1 nitrogen linear
velocity.
Working range
To test the column low-temperature chromatographic separation
performance, 3-methylpentane (bp, 64 ꢀC) and methylcyclopentane
(bp, 72 ꢀC), with boiling points near to that of n-hexane (bp, 69 ꢀC),
were added to the Grob test mixture. As expected, good separation
could be realized at 30 ꢀC, indicating that the minimum allowable
operating temperature (MiAOT) of the column should be controlled
below 30 ꢀC. The reason is that the low Tg (ꢂ42.8 ꢀC) of P(BPTMC)-
alt-ODMS results in a low MiAOT when used as stationary phase for
GC. The column bleeding of P(BPTMC)-alt-ODMS and Dexsil-300
under the same conditions (length, 15 m; i.d., 0.25 mm; lm
thickness, 0.31 mm) is respectively determined at 360 C, 380 C,
and 400 ꢀC without any injection, with the results listed in Table 2.
Meanwhile, the bleeding from the empty column was also
measured. The table shows that the high temperature performance
of P(BPTMC)-alt-ODMS column is similar to that of Dexsil-300, and
Application
The gas chromatograms of the separations of polyethylene
pyrolysis product and petroleum components using P(BPTMC)-
alt-ODMS columns are illustrated in Fig. 5 and 6, respectively.
Good chromatographic separation performance with low
bleeding rate can be achieved with practical samples, where the
polyethylene pyrolysis products, alkane and alkene with
ꢀ
ꢀ
ꢀ
its maximum operating temperature is controlled near 400 C in
the present study.
Fig.
7 Chromatogram of aromatic hydrocarbon mixtures with
P(BPTMC)-alt-ODMS as stationary phase. Capillary length 30 m, film
thickness 0.31 mm, i.d. 0.25 mm. Temperature program: from 120 ꢀC
(kept for 5 min), then to 320 ꢀC at 4 ꢀC minꢂ1, 12 cm sꢂ1 gas nitrogen
linear velocity. Peaks: (1) acetophenone; (2) indene; (3) naphthane; (4)
naphthalene; (5) 2-methylnaphthalene; (6) 1-methylnaphthalene; (7)
Fig.
5
Chromatogram of polyethylene pyrolysis product with 8-hydroxyquinoline; (8) biphenyl; (9) 1-nitronaphthalene; (10) 2,20-
P(BPTMC)-alt-ODMS as stationary phase. Capillary length 30 m, film dihydroxybiphenyl; (11) 5-acenaphthenol; (12) 3,5-dinitrophenol; (13)
thickness 0.31 mm, i.d. 0.25 mm. Temperature program: from 60 ꢀC 2,20-methylenebiphenyl; (14) phenanthrene; (15) anthracene; (16)
(kept for 5 min), then to 370 ꢀC (kept for 5 min) at 5 ꢀC minꢂ1, 12 cm sꢂ1 benzil; (17) anthraquinone; (18) triphenylmethane; (19) 1,8-naphthalic
nitrogen linear velocity.
anhydride; (20) chrysene; (21) 1,4-dibenzoylbenzene.
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identical carbon numbers, can be separated. Compared with
Dexsil-300 and despite the slightly weak thermal stability of the
column, the good separation characteristics and column effi-
ciencies of P(BPTMC)-alt-ODMS make the column especially
suitable as stationary phases in HTGC for analyzing non-polar
alkane mixtures with high boiling point.
To test the capability of P(BPTMC)-alt-ODMS column for
separating polycyclic aromatic hydrocarbons, the chromato-
gram of aromatic hydrocarbon mixtures was measured, with the
results shown in Fig. 7. Excellent separation ability of the
column for polar phenols containing a hydroxyl group and
polycyclic aromatic hydrocarbons can be observed, reecting its
advantage in separating polar aromatic mixture as stationary
phase.
2 A. Bemgard, L. Blomberg, M. Lymann, S. Claude and
R. Tabachl, J. High Resolut. Chromatogr., 1987, 10, 302.
3 A. Bemgard, L. G. Blomberg and K. E. Markides, J. High
Resolut. Chromatogr., 1985, 8, 632.
4 E. Hedaya, J. H. Kawakami, P. W. Kopt, G. T. Kwiatkowski,
D. W. Mcneil, D. A. Owen, E. N. Peters and R. W. Tulis, J.
Polym. Sci., Polym. Chem. Ed., 1977, 15, 2229.
5 M. Petsch, Anal. Bioanal. Chem., 2005, 383, 323.
6 M. B. Roller and J. K. Giclham, J. Appl. Polym. Sci., 1973, 17,
2141.
7 G. E. Pollock, Anal. Chem., 1972, 44, 634.
¨
8 X. Bernhard, M. Helm, H. Kahlig and W. Rauter, J.
Chromatogr. A, 2004, 1042, 147.
9 L. G. Blomberg, J. High Resolut. Chromatogr., 1982, 5, 520.
¨
10 X. B. Mayer, H. Kahlig and W. Rauter, J. Chromatogr. A, 2003,
993, 59.
Conclusion
11 R. Aichholz and E. Lorbeer, J. Microcolumn Sep., 1996, 8, 553.
12 Q. Wu, M. Helem, C. A. Cramers and J. A. Rijks, J. High
Resolut. Chromatogr., 1990, 13, 811.
13 T. Welsch and V. Teichman, J. High Resolut. Chromatogr.,
1991, 14, 153.
P(BPTMC)-alt-ODMS is a novel stationary phase for gas chro-
matography and has several benecial properties in chro-
matographic separation.
(I) The increased thermal stability caused by introducing the
BPTMC unit to the backbone resulted in increased glass tran-
sition temperature. The operating temperature is between 30 ꢀC
¨
14 M. Petsch, X. Bernhard and M. V. Sollner, Anal. Bioanal.
Chem., 2005, 383, 322.
ꢀ
and 400 C.
15 E. Kaal and H. G. Janssen, J. Chromatogr. A, 2008, 1184, 43.
16 C. Saridara and S. Mitra, Anal. Chem., 2005, 77, 7094.
17 M. Karwa and S. Mitra, Anal. Chem., 2006, 78, 2064.
18 Z. Y. Gu and X. P. Yan, Angew. Chem., Int. Ed., 2010, 49, 1477.
19 N. Chang, Z. Y. Gu and X. P. Yan, J. Am. Chem. Soc., 2010, 132,
13645.
20 N. Chang and X. P. Yan, J. Chromatogr. A, 2012, 1257, 116.
21 W. Fink, Helv. Chim. Acta, 1968, 51, 1743.
22 L. W. Breed and J. C. Wiley, J. Inorg. Chem., 1972, 11, 1634.
23 Z. M. Xie, Q. S. Li, J. T. Wang and Z. S. Xie, Acta Polym. Sin.,
1979, 4, 215.
(II) BPTMC unit acts such as diphenylsiloxy group in chro-
matographic separation. The stationary phase using P(BPTMC)-
alt-ODMS thus possesses higher middle polarity than Dexsil-
300.
(III) P(BPTMC)-alt-ODMS is easy to coat in the capillary
column, which imparts high column efficiency.
(IV) Such stationary phase is suitable for separating nonpolar
alkanes and polar aromatic compounds.
In summary, the use of P(BPTMC)-alt-ODMS as stationary
phase for HTGC exhibit great potential in practical applications.
24 Y. P. Zhu, L. Guo and Z. J. Zhang, J. Appl. Polym. Sci., 2007,
103, 611.
Acknowledgements
25 W. Q. Peng and Z. M. Xie, J. Ploy. Bull, 2000, 1, 1.
26 J. B. Zhao and Z. M. Xie, J. Appl. Polym. Sci., 2005, 97, 1484.
27 R. P. Alexander and H. Schroeder, Inorg. Chem., 1966, 5, 493.
28 H. Schroeder, S. Papertti, R. P. Alexander, J. F. Sieckhaus and
L. H. Theodore, Inorg. Chem., 1969, 8, 2444.
29 J. K. Grob, G. Grob and K. Grob, J. Chromatogr., 1978, 156, 1.
30 K. Grob and G. Grob, J. Chromatogr., 1981, 207, 291.
31 L. Rohrschneider, J. Chromatogr., 1966, 22, 6.
32 W. O. McReynolds, J. Chromatogr. Sci., 1970, 8, 685.
This study was supported by the National Natural Science
Foundation of China (no. 21275090), the National Science
Foundation for Fostering Talents in Basic Research of the
National Natural Science Foundation of China (no. J1103314),
and Technology Development Plan of Shandong province (no.
2014GGX107010).
References
1 A. S. Pereira and F. R. Aquino Neto, TrAC, Trends Anal. Chem.,
1999, 18, 126.
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