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Research Article
Determination of the volatiles from tobaccoby capillary gas chromatography withatomic emission detection and massspectrometry
A new gas chromatograph-atomic emission detector (GC-AED) coupled with Deans
switching technique for analyzing volatiles from tobaccos were developed. The detector
operating parameters (reagent gas pressure and make-up gas flow rate) were optimized.
The detection limits for the elements carbon (193 nm), hydrogen (486 nm) and oxygen
(171 nm) ranged 0.05–0.2, 0.05–0.3 and 1–11 ng, respectively, depending on the
compound. The sensitivity and linearity for the elements carbon (193 nm), hydrogen
(486 nm) and oxygen (171 nm) decreased in the order O4H4C. Calibration curves were
obtained by plotting peak area versus concentration, and the correlation coefficients
relating to linearity were at least 0.9359. Elemental response factors measured on these
channels, relative to the carbon 193-nm channel, were hydrogen, 0.38–0.48 (mean
%RSD 5 5.64), and oxygen, 0.085–0.128 (mean %RSD 5 14.9). The evaluation was also
done for the new technique and for an established GC-MS technique for the same real
samples. The results of GC-AED and GC-MS showed that there was a relatively good
agreement between the two sets of data.
Keywords: Deans switching / Elemental response factors / GC-AEDDOI 10.1002/jssc.201100732
1 Introduction
The volatile constituents of tobacco leaf are of interest since
their structures will provide information about the cigarette
flavor. Numerous studies on volatile components of the
cigarette and its smoke have been carried out, and hundreds
of components have been reported [1–5]. A sampling
method is required, such as liquid–liquid extraction (LLE)
[6–8], simultaneous distillation–extraction [9, 10], solid-
phase extraction [11], a combination of the former
techniques [12] or solid-phase microextraction [13], which
will provide sufficient quantities of material to obtain
information about the trace components, since many of
the important volatile compounds occur only in very low
concentration.
Gas chromatography with mass spectrometric detection
(GC-MS) has become the main analytical tool for the
determination of the structure and elemental composition
of the components of complex mixtures, for example,
traditional Chinese medicine [14] or herbal drugs [15].
Furthermore, it has been suggested that other technical
improvements, such as the Deans switch microfluidic
device, offer more options and potential for problem-solving
and optimization of GC-based analytical systems [16, 17].
The Deans switching device should make easy set-up for
multidimensional gas chromatographic analysis and heart-
cutting properties possible.
Recently, gas chromatography with atomic emission
detection (GC-AED) is a powerful technique that offers
high-resolution separation of components in a complex
matrix and highly selective spectrometric detection [18–21].
GC-AED provides information about the occurrence of
individual elements in the analyzed compounds. Monitor-
ing at different wavelengths is carried out to measure the
atomic emission of the chosen elements, and data are
recorded as element selective chromatograms. Furthermore,
information about possible empirical formulae can be
obtained by calibrating the instrument with standard
compounds of known composition and comparing it with
the response of the unknown impurity. However, the large
amount of the solvent comes with a risk of rapidly
contaminating the fused-silica discharge tube of the AED
Gang Li1,2
Da Wu2
Ye Wang2
Wenyan Xie2
Xiangmin Zhang1
Baizhan Liu2�
1Department of Chemistry, FudanUniversity, Shanghai,P. R. China
2Technology Center, ShanghaiTobacco Group Co., Ltd,Shanghai, P. R. China
Received August 17, 2011Revised October 24, 2011Accepted October 24, 2011
Abbreviations: ERF, elemental response factor; GC-AED, gaschromatography with atomic emission detection; GC-MS,gas chromatography with mass spectrometry; LLE,liquid–liquid extraction; psi, pounds per square inch
�Additional correspondence: Professor Baizhan Liu
E-mail address: Liubz@sh.tobaco.com.cn
Correspondence: Professor Xiangmin Zhang, Department ofChemistry, Fudan University, Shanghai 200433, P. R. ChinaE-mail: xminzhang@fudan.edu.cnFax: 186-21-65643983
& 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim www.jss-journal.com
J. Sep. Sci. 2012, 35, 334–340334
detector, potentially limiting its usefulness, and requiring
frequent system maintenance.
It is worthwhile to stress that complementary informa-
tion can be gathered from GC-AED coupled with Deans
switch. The potential merit of this system could be also
applied to the multidimensional GC technique. Separation
may be enhanced through ‘heart-cutting’ peaks from one
GC column onto a second GC column with a stationary
phase of different selectivities using a Deans switch
assembly. For added benefit, the solvent is not introduced in
the second column or in the AED detector, avoiding
contaminating the fused-silica discharge tube, column
degradation, target analyte peak detection/integration and
frequent system maintenance issues.
As far as we know, the application of GC-AED coupled
with Deans switching device as a routine tobacco screening
tool has not yet been reported. In view of this, in this
contribution, we describe an approach using GC-AED
coupled with Deans switching for the analysis of volatile
fractions of tobaccos. Detection limits, regression analyses
and elemental response factors (ERFs) are determined for
carbon, hydrogen and oxygen, although the main aim of this
study is to evaluate the ability of quantitative GC-MS and
GC-AED coupled with Deans switch when analyzing
tobacco samples.
2 Materials and methods
2.1 Samples and chemicals
Typical aged flue-cured tobacco leaves from different
provinces in China were prepared for these studies. A 10-g
aliquot of each sample was collected and mixed thoroughly,
put into an oven at 401C for 8 h to remove moisture, and
then ground to 40–60 mesh powder.
Anhydrous dichloromethane used as solvents from
Merck (Darmstadt, Germany) was of analytical grade
quality. It was used without further purification. Phenethyl
acetate (Sigma, St. Louis, MO, USA) was used as an
internal standard. Stock anhydrous dichloromethane stan-
dards of phenylmethanal, benzenemethanol, b-damascen-
one, solanone, (E)-geranylacetone and b-ionone were all
purchased from Sigma and were all in GC purities. Stock
standard solutions of 500 mg/mL of each compound were
prepared by dissolving 5 mg in 10 mL of dichloromethane
and were used to optimize GC conditions. All were refri-
gerated at 41C during storage. Anhydrous sodium sulfite
(J&K Scientific, Shanghai, China) was prepared before use.
The plasma gas and carrier gas used for GC was helium
(99.9999% purity). A VICI Model I-23572-HP2 (USA)
helium purifier was used inline between the helium tank
and the plasma cavity. The reagent gases for the AED
were oxygen, hydrogen and 10% methane-in-nitrogen.
Nitrogen was used for purging the AED system. All the
gases were supplied by Shanghai No. 5 Steel Works
(Shanghai, P. R. China).
2.2 Isolation of the volatile components
A 10.0-g tobacco sample was placed in a 500-mL flask,
combined with 350 mL water, previously salted with 10%
anhydrous sodium sulfite. The solution was water steam
distilled for 20 min. A distillate of 150 mL was collected in a
separation funnel to perform a LLE, which was extracted by
anhydrous dichloromethane (each 15� 3 mL) under
mechanical shaking for 5 min. The organic phases were
separated from the aqueous phase, and the funnel was
washed with 10 mL of dichloromethane. The resulting
extract layers were combined and then were added to
150 mL of internal standard solution (4.5 mg/mL). The
organic phases were collected in a flask and concentrated
to dryness using a rotary vacuum evaporator at 401C. The
dry extract was dissolved in 1 mL of dichloromethane. No
clean-up was necessary. All glasswares were cleaned and
heated for 2 h at 1501C prior to use.
2.3 Chromatography
2.3.1 GC-AED
The AED used in this study was a G-2350 Model (Joint
Analytical Systems GmbH, Germany) equipped with a
photodiode array (PDA) having a nominal wavelength range
of 160–800 nm and a spectral resolution of 0.1 nm at
400 nm. The concave holographic grating had a flat focal
plane along which the PDA could be moved. Plasma power
was supplied by a microwave magnetron tube. The AED had
been described in detail elsewhere [22–24]. The 1.0-mm
id� 47-mm long fused-silica discharge tube was water
cooled and fitted with a fused-silica window, which was
purged with 35 mL/min of reagent grade helium. Groups of
elements were scanned, without background correction, for
carbon, hydrogen and oxygen at 193, 486 and 171 nm,
respectively.
To vent the solvent before entering the plasma and
prevent carbonaceous deposition on the wall of the
discharge tube, the analyses were carried out on the GC-
AED coupled with Deans switching device combination. As
illustrated in Fig. 1, the GC was equipped with a split/
splitless inlet and a capillary flow technology based Deans
switching system. The primary and the second columns
were both 30 m� 0.25 mm id� 0.25 mm HP-5 (Agilent
Technologies) installed in the GC oven. A restrictor, R1
(3 m� 180 mm id deactivated fused silica, Agilent Technol-
ogies), was connected between the second output of the
Deans switch and a monitoring flame ionization detector
(FID). In our experiment, the resolution of all examined
peaks obtained with the system was sufficient, thus using
the columns with a stationary phase of different selectivities
coupled with Deans switch assembly was not necessary.
The Deans switching operation was demonstrated
previously [25, 26]. In this configuration, a solenoid valve,
located outside the oven, was in the off position. The
J. Sep. Sci. 2012, 35, 334–340 Other Techniques 335
& 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim www.jss-journal.com
effluent from the first column was ‘pushed’ with an addi-
tional flow towards the monitor FID detector. When the
solenoid valve was actuated (from the software), the flow
now entered the other arm to the Deans switching. And the
flow from the first column was redirected into the second
column. In both valve positions, pressures through restric-
tor R1 and column 2 were similar.
Sample volumes of 1 mL were injected in splitless mode
at an injection port temperature of 2801C, applying a pres-
sure pulse of 26 pounds per square inch (psi). The initial
column temperature was set at 451C for 1 min and then
increased to 2501C (2.51C/min, 5 min hold). The pressure at
the outlet of the first column and the inlet of the second
column was 18.4 psi, resulting in a flow of 2 mL/min
through the second column (to AED). The final part of the
GC column was used as a transfer line to the detector. The
transfer line and the detector cavity were maintained at
2801C. The scavenger gases were hydrogen, oxygen and 10%
methane-in-nitrogen at 11.5, 21 and 30 psi, respectively. The
spectrometer was purged with nitrogen at 400 mL/min.
Filter and back amount adjustments were set according to
the default specifications.
2.3.2 GC-MS
Samples were analyzed with a Hewlett-Packard Model 7890
GC interfaced to a Model 5975A mass-selective detector. A
30-m� 0.32-mm capillary column coated with 0.25-mm HP-
5 was used for all analyses. The inlet and the detector were
set at 2801C, respectively. The MS ion source was heated to
2301C, and the quadrupole was kept at 1501C. Their
collision energy for MS fragmentation was at 70 eV,
scanning from m/z 40 to 330 in one scan. The mass
spectral identification of the compounds were carried out by
comparing with the NIST98 (National Institute of Standards
and Technology, Gaithersburg, MD, USA) mass spectral
library as well as to the Wiley 7.0 (Wiley, New York, USA)
mass spectral library. Qualitative analysis (mass spectral
data) was verified by comparing the retention indices and
mass spectra of identified compounds with those of
authentic reference substances. Quantitative data were
obtained by the internal standard method using phenethyl
acetate as the internal standard or standards as reference
substances, respectively, without considering calibration
factors (i.e. F 5 1.00 for all compounds). The GC column
and chromatographic conditions and settings were the same
as those used for GC-AED runs.
3 Results and discussion
3.1 Optimization of AED parameters
With GC-AED, the elements were in groups on the
condition that close emission line wavelengths and the
same scavenger gases were used [27]. For this reason, three
sequential chromatographic runs were required to obtain
chromatograms for C, H and O. The chromatogram for
carbon (193 nm) was obtained using oxygen and hydrogen
as scavenger gases. While the emission line for hydrogen lay
in 486 nm, this element required oxygen as the sole
scavenger gas. The chromatogram for oxygen (171 nm)
was obtained using hydrogen and 10% methane-in-nitrogen
as the scavenger gas. Their presence, combined with the
retention time, would usually be to identify a given sample.
The detector operating parameters (reagent gas pressure
and make-up gas flow rate) were optimized to obtain the
highest degree of sensitivity. For those emission lines that
required two scavenger gases simultaneously, independent
optimization of both the oxygen and hydrogen pressures was
carried out. First, the hydrogen pressure was held constant at
5 psi, the default value provided by the software, while oxygen
was varied from 5 to 30 psi to determine the optimum oxygen
pressure. For the C (193 nm) emission line, an increase in
oxygen pressure led to a decrease in peak area up to 15 psi,
which remained almost constant thereafter. A pressure of
20 psi was adopted to avoid accumulation of elemental
carbon in the AED discharge tube. The oxygen reagent gas
pressure was then held constant at its optimum value,
whereas the hydrogen pressure was varied from 5 to 25 psi.
The optimum value of the hydrogen pressure was 11.5 psi.
Using the same procedure, 30 psi of the 10% methane-in-
nitrogen was selected as the optimum value when analyzing
the element of the oxygen (171 nm).
The supplementary helium added to the column flow
prior to detection (make-up gas) affects the sensitivity and
peak shape of the components. To determine the optimum
helium (make-up gas) flow rate, which provided the maxi-
mum sensitivity, the internal standard solution was injected
and the flow rate was varied from 20 to 100 mL/min. A flow
rate of 70 mL/min provided the maximum sensitivity for all
the components at the C (193 nm) emission line. Monitor-
ing the same emission line showed very wide peaks and
Figure 1. Configuration of GC-AED coupled with Deans switch-ing device.
J. Sep. Sci. 2012, 35, 334–340336 G. Li et al.
& 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim www.jss-journal.com
overlapping at flow rates slower than the optimized value.
Under the optimized conditions, standard solutions deter-
mined eluted in the following order: phenylmethanal,
benzenemethanol, phenethyl acetate, b-damascenone, sola-
none, (E)-geranylacetone and b-ionone.
3.2 Optimization of the extraction procedure
Good results were obtained by LLE. Preliminary experi-
ments were carried out using several organic solvents
(hexane, isooctane, diethyl ether, dichloromethane and ethyl
acetate) and mixtures. The extraction procedure using
dichloromethane provided excellent results. In an attempt
to improve the extraction efficiency by increasing the ionic
strength of the samples, sodium sulfite was added to the
samples, which could improve the extraction of these
components with a high degree of water solubility [28].
The extraction percentages were optimal for a 10:1 water/
dichloromethane ratio. Higher sodium sulfite concentra-
tions did not improve extraction percentages [29, 30].
Different shaking times were assayed and 5 min was
sufficient to obtain the highest extraction percentage using
the proposed GC-AED and GC-MS method. After extraction,
the organic phase was evaporated to dryness and the dry
extract was dissolved with 1 mL of dichloromethane.
3.3 Detection limits and regression analysis
In this experiment, working standard solutions were
prepared at different concentrations. The C (193 nm), H
(486 nm) and O (171 nm) emission lines were monitored.
Each concentration was injected into the GC five times to
improve the quality of the information.
Detection limits were calculated using a signal-to-noise
ratio of 3 for all investigated compounds and values are
given in Table 1. The analyte detection limits for the
nonmetals carbon, hydrogen and oxygen were 0.05–0.2,
0.05–0.3, and 1–11 ng, respectively. This indicated that the
order of decreasing sensitivity to molecular structure was
O4H4C. These detection limit ranges also suggested that
errors using molecular-independent quantification (the use
of a single standard to quantify a series of compounds
having similar elemental distribution but different mole-
cular structures) would be larger for oxygen than for carbon
or hydrogen.
The correlation coefficients derived from linear regres-
sions and the standard errors of the estimates are also
included in Table 1. Linear calibration curves were obtained
by plotting peak areas versus concentrations. The results
Table 1. Calibration parameters at different emission lines
Analyte GC-AED
Carbon 193 nm Hydrogen 486 nm Oxygen 171 nm
Slope r2 LOD (ng) Slope r2 LOD (ng) Slope r2 LOD (ng)
Phenylmethanal 111.3 0.9985 0.15 42.1 0.9818 0.3 29.6 0.9507 1.5
Benzenemethanol 79.75 0.9986 0.15 38.6 0.9857 0.2 34.8 0.9423 2
Phenethyl acetate 85.53 0.9996 0.2 46.4 0.9941 0.2 31.5 0.9494 1
b-Damascenone 95.62 0.9993 0.05 58.3 0.9954 0.15 27.8 0.9451 8
Solanone 125.1 0.9997 0.05 67.8 0.9963 0.05 14.4 0.9007 6
(E)-Geranylacetone 82.33 0.9995 0.05 63.5 0.9966 0.075 10.9 0.9303 8
b-Ionone 99.81 0.9997 0.05 71.1 0.9958 0.09 10.6 0.9328 11
Table 2. Elemental response factors (ERF)a)
Analyte H (486 nm) (%RSD) O (171 nm) (%RSD)
Furfural 0.455 (10.6) 0.128 (8.2)
2-Furanmethanol 0.42 (9.7) 0.123 (10.6)
Protoanemonine 0.41 (9.8) 0.119 (7.5)
Phenylmethanal 0.425 (11.6) 0.103 (15.4)
6-Methyl-5-hepten-2-one 0.385 (6.85) /
Benzenemethanol 0.4 (6.23) 0.123 (16.2)
Benzeneacetaldehyde 0.39 (7.21) 0.123 (17.7)
2-Acetylpyrrole 0.405 (8.6) 0.118 (15.5)
Phenylethyl alcohol 0.6 (5.79) 0.121 (6.8)
Indole 0.465 (5.88) /
4-Vinylguaiacol 0.38 (6.15) 0.118 (6.2)
Solanone 0.42 (5.03) 0.121 (24.1)
b-Damascenone 0.395 (6.89) /
(E)-b-Bamascone 0.425 (6.57) /
(E)-Geranylacetone 0.435 (4.38) 0.106 (20.5)
b-Ionone 0.385 (7.2) /
Dihydroactinidiolide 0.455 (2.97) 0.085 (13.7)
Megastigmatrienone 1 0.415 (2.76) /
Megastigmatrienone 2 0.39 (3.32) 0.118 (19.5)
Megastigmatrienone 3 0.405 (2.05) /
Megastigmatrienone 4 0.44 (2.15) 0.12 (18.3)
3-Oxo-a-ionol 0.43 (5.28) /
Neophytadiene 0.44 (1.15) /
Farnesyl acetone 0.42 (2.43) 0.102 (17.8)
Methyl palmitate 0.46 (3.77) 0.117 (20.3)
Palmitic acid 0.48 (2.33) /
Mean ERF (mean %RSD) 0.428 (5.64) 0.115 (14.9)
a) (Elemental area counts/carbon 193 area counts)� (no. of
carbon atoms/no. of element atoms).
J. Sep. Sci. 2012, 35, 334–340 Other Techniques 337
& 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim www.jss-journal.com
obtained showed the following order of sensitivity:
C4H4O, as measured by the coefficient of determination
(r2). The poorer precision for oxygen could result from
chromatographic tailing resulting from the greater polarity
of these compounds relative to the neutral analytes.
3.4 Elemental response factor
An ERF was calculated from the average of ERF for each
concentration level used for regression analysis using the
expression [31]. ERF 5 (elemental area counts/carbon 193-
nm area counts)� (no. of carbon atoms/no. of element
atoms). Table 2 shows the ERF data for the hydrogen 486-
nm and oxygen 171-nm channels. The order of increasing
%RSD (mean value) was H (5.64)oO (14.9), and the order
of increasing ERF was O (0.115)oH (0.428).
In principle, the very high temperatures in the MIP
plasma should result in the complete atomization of analyte
molecules entering from the GC column so that AED
response should be independent of molecular structure. In
fact, compound-independent calibration had not proved
Figure 2. Total ion chromatogram of volatilecomponents obtained from flue-cured tobac-co from Henan in China. For identified peaknumbers, see Table 3.
Figure 3. Typical GC-AEDchromatograms of volatilecomponents obtained fromflue-cured tobacco from Henanin China by element wave-length: (A) C 193 nm and (B) O171 nm. For identified peaknumbers, see Table 3.
J. Sep. Sci. 2012, 35, 334–340338 G. Li et al.
& 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim www.jss-journal.com
reliable [32, 33] for electron-rich aromatic structures with
large dissociation energies because of incomplete decom-
position and/or the formation of small molecular species by
recombination reactions [34]. Similar results were observed
here: the ERF oxygen and hydrogen for different
compounds extracted from tobacco determined under
the same analytical conditions differed slightly (Table 2).
The poorer precision for O might have been based on the
detector performance at the wavelength or self-absorption
between the emission source and the spectrometer.
3.5 Analysis of flue-cured tobacco samples
Complementary measurements for the proposed LLE
method were also performed on a GC-MS system with
exactly the same extracts as used for the GC-AED, with the
aim of confirming the identity of the compounds detected
by GC-AED. The selectivity of the AED was studied by
comparing GC-MS and GC-AED chromatograms of real
samples. The total ion chromatogram and the typical GC-
AED chromatograms of the volatiles from Henan province
are shown in Figs. 2 and 3, respectively. The selectivity of
the AED oxygen channel was evident: hardly any interfering
peaks showed up.
keton
es
aldeh
ydes
alcoh
ols
phen
ols
aliph
atic a
cods
neop
hytad
iene
the ot
her c
ompo
nents
MSDAED
0
20
40
60
80
Figure 4. Comparing the two techniques (GC-MS and GC-AED),for percentages of the volatile components obtained for ketones,neophytadiene, aliphatic acids, alcohols, aldehydes, phenolsand the other components’ fortification level in the flue-curedtobaccos from Henan province in China.
Table 3. The contents of the volatile components of flue-cured tobaccos in Henan, Guizhou, Yunnan and Liaoning province in China
detection with GC-MS and GC-AED
No. Analyte Henan (mg/g) Guizhou (mg/g) Yunnan (mg/g) Liaoning (mg/g) Identified by MS
or standards
MS AED MS AED MS AED MS AED
1 Furfural 15.45 14.85 24.51 22.38 9.631 8.711 23.41 22.26 S
2 2-Furanmethanol 8.408 7.93 6.749 6.027 1.814 1.533 15.29 14.77 S
3 5-Methylfuranone 0.5352 0.348 0.3634 tr 0.112 tr 0.4382 tr MS
4 Protoanemonine 5.182 5.416 5.16 5.923 0.89 0.663 9.388 10.12 MS
5 2-Acetylfuran 0.6238 tr 0.6866 tr 0.3111 tr 1.77 tr MS
6 Phenylmethanal 8.395 7.321 7.762 6.819 1.281 1.107 9.965 9.462 S
7 6-Methyl-5-hepten-2-one 1.402 1.634 1.112 1.342 1.533 1.476 1.1807 0.938 MS
8 Benzenemethanol 11.21 13.03 38.23 39.18 27.57 28.43 35.32 35.93 S
9 Benzeneacetaldehyde 13.81 12.45 1.205 1.088 1.145 1.051 3.083 2.841 MS
10 2-Acetylpyrrole 10.15 8.96 9.364 8.957 5.69 5.137 7.048 7.11 MS
11 Phenylethyl alcohol 14.19 14.03 22.24 22.37 17.2 17.44 21.09 21.84 MS
12 Indole 2.472 tr 3.395 3.021 1.146 tr 1.764 tr MS
13 4-Vinylguaiacol 6.752 5.88 10.13 9.725 3.632 3.193 7.111 6.876 MS
14 Solanone 21.76 22.41 35.62 35.84 41.1 41.72 57.67 59.43 S
15 b-Damascenone 10.23 10.67 13.3 13.53 8.85 9.06 9.457 9.832 S
16 (E)-b-Bamascone 2.087 2.356 2.651 2.411 2.774 2.167 2.242 2.567 MS
17 (E)-Geranylacetone 16.87 14.91 4.939 5.283 5.894 6.112 7.492 7.734 S
18 b-Ionone 2.952 3.045 1.532 1.779 1.754 2.032 0.2094 tr S
19 Dihydroactinidiolide 17.08 17.33 12 13.07 9.757 9.771 10.72 11.13 S
20 Megastigmatrienone 1 8.897 8.626 9.053 8.686 6.226 5.325 5.005 4.792 MS
21 Megastigmatrienone 2 51.14 52.18 38.82 38.63 31.56 33.46 25.41 26.68 MS
22 Megastigmatrienone 3 7.651 7.925 5.694 5.841 5.005 4.873 3.755 3.276 MS
23 Megastigmatrienone 4 52.11 53.23 43.21 44.46 32.27 30.21 28.59 28.06 MS
24 3-Oxo-a-ionol 5.65 5.97 7.613 7.775 tr tr 4.517 4.882 MS
25 Neophytadiene 1080 1101 1463 1501 988.5 1010 871.7 901.7 MS
26 Farnesyl acetone 23.97 24.51 tr tr tr tr 4.488 4.923 MS
27 Methyl palmitate 29.19 29.31 56.35 57.33 20.59 23.11 21.91 23.44 MS
28 Palmitic acid 88.35 84.67 108.5 107.64 47.44 45.78 140.5 138.8 MS
tr, trace amount.
J. Sep. Sci. 2012, 35, 334–340 Other Techniques 339
& 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim www.jss-journal.com
The results of GC-AED and GC-MS analysis of the tobacco
are given in Table 3, which showed that there was a relatively
good agreement between the two sets of data. As it could also
be calculated from Table 3, the proportion of the ketones,
neophytadiene, aliphatic acids, alcohols, aldehydes, phenols
and the other components relative to the total amount of the
volatiles in tobacco was not very different for the tobacco from
different provinces in China [35, 36]. As illustrated in Fig. 4, the
percentages of ketones, neophytadiene, aliphatic acids, alcohols,
aldehydes, phenols and the other components were obtained in
Henan province. The results also showed good agreement
between GC-MS and GC-AED analysis. This indicated that the
AED coupled with Deans switch was a good alternative for
chromatography when analyzing tobacco samples.
4 Concluding remarks
The sensitivity and precision of GC-AED coupled with Deans
switching device for tobacco analysis were reported. Nano-
gram analyte detection limits for carbon, hydrogen and
oxygen were obtained. Precision worsens as measured by
regression coefficient of determination or ERF in the order
C4H4O. Detection limits decreased in the order O4H4C,
which approximated the order of decreasing first ionization
energies. Compared with GC-MS technique, the selectivity of
the GC-AED was evident. The results showed that GC-AED
coupled with Deans switching technique was a useful tool for
analyzing the volatiles from tobaccos.
The authors are grateful to Science and TechnologyCommission of Shanghai (Grant No. 11R21422000) forfinancial support.
The authors have declared no conflict of interest.
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