Supercritical fluid extraction (SFE) is an efficient extraction technique for the separation of various organic compounds from herbs, or more generally, from plant materials. These proporties of SFE make the products more advantageous in the field of foods, pharmaceuticals, and cosmetics. The aim of this study was to investigate the effect of pressure and particle size on the extraction yield and the quality of the extracts

Boris MANDIC

Goran TADIC

Milovan JOTANOVIC

Vladan MICIC

Zika LEPOJEVIC

The Annals of “Dunarea de Jos” University of Galati Fascicle IX Metallurgy and Materials Science

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THE ANNALS OF “DUNAREA DE JOS” UNIVERSITY OF GALATI. 
FASCICLE IX. METALLURGY AND MATERIALS SCIENCE 
N0. 1 – 2008, ISSN 1453 – 083X 
 
 
 
 
INFLUENCE PRESSURE AND SIZE PARTICLE  
TO EXTRACTION BY CO2
 
Vladan MICIC1, Zika LEPOJEVIC2, Milovan JOTANOVIC1, 
Goran TADIC1, Boris MANDIC3 
1 Faculty of  Technology, University of Eastern Sarajevo, Karakaj bb, Zvornik, Bosnia and Herzegovina 
2 Faculty of Technology, University of Novi Sad, Bulevar Cara Lazara 1, Novi Sad, Serbia 
3 Faculty of Chemistry, University of Belgrade 
e-mail adress: Vlado21micic@ptt.yu
 
ABSTRACT 
 
Supercritical fluid extraction (SFE) is an efficient extraction technique for the 
separation of various organic compounds from herbs, or more generally, from plant 
materials. These proporties of SFE make the products more advantageous in the 
field of foods, pharmaceuticals, and cosmetics. The aim of this study was to 
investigate the effect of pressure and particle size on the extraction yield and the 
quality of the extracts.  
 
KEYWORDS: supercritical extraction, carbon-dioxide, sage, solvent, size 
particle, extracts 
 
1. Introduction 
 
With increasing public interest in herbal medicine 
and natural products, the conventional methods such 
as hydro-distillation and solvent extraction were 
found unsatisfactory. To improve efficiency and 
selectivity of the extraction, alternative extraction 
techniques such as supercritical extraction started to 
be developed.  
Supercritical extraction is not widely used yet, but 
as new technologies are coming there are more and 
more viewpoints that could justify it, as high purity, 
residual solvent content and environment protection 
[1, 2, 3]. Some of the advantages and disadvantages 
of extraction by supercritical fluids compared to 
extraction by conventional liquid solvents for 
separations are: 
 
Advantages 
 
• Dissolving power of the SCF (supercritical 
fluid) is controlled by pressure and/or 
temperature  
• SCF is easily recoverable from the extract 
due to its volatility:  
• Non-toxic solvents leave no harmful residue  
• High boiling components are extracted at 
relatively low temperatures  
• Separations not possible by more traditional 
processes can sometimes be effected  
• Thermally labile compounds can be 
extracted with minimal damage as low 
temperatures can be employed during the 
extraction  
 
 
Disadvantages 
 
 
• Elevated pressure required  
• Compression of solvent requires elaborate 
recycling measures to reduce energy costs  
• High capital investment for equipment       
                                                                                              
The choice of the SFE (supercritical fluid 
extraction) solvent is similar to the regular extraction.  
Principle considerations are the followings:  
• Good solving property  
• Inert to the product  
• Easy separation from the product  
• Cheap  
Carbon dioxide is the most commonly used SCF, 
due primarily to its low critical parameters (31.1°C, 
73.8 bar), low cost and non-toxicity.  
Dependence pressure and density by temperature 
are shown  in Fig. 1 and Fig. 2 [2].  
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THE ANNALS OF “DUNAREA DE JOS” UNIVERSITY OF GALATI. 
FASCICLE IX. METALLURGY AND MATERIALS SCIENCE 
N0. 1 – 2008, ISSN 1453 – 083X 
 
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Fig. 1.  Carbon -dioxide pressure - 
temperature phase diagram 
 
 
Fig.  2. Carbon dioxide density- 
pressure phase diagram 
 
The special properties of supercritical fluids bring 
certain advantages to chemical separation processes. 
Several applications have been fully developed and 
commercialized.  
SFE is applied in food and flavoring industry as 
the residual solvent could be easily removed from the 
product no matter whether it is the extract or the 
extracted matrix. The biggest application is the 
decoffeinization of tea and coffee. A process for 
removal of caffeine from coffee using supercritical 
carbon dioxide was patented in the United States in 
1974, and a commercial plant went on stream in the 
FRG in 1978. Other important areas are the extraction 
of essential oils and aroma materials from spices. 
Brewery industry uses SFE for the extraction of hop. 
The method is used in extracting some edible oils and 
producing cholesterine-free egg powder. 
Consequence, supercritical CO2 extraction as an 
environmentally friendly and efficient extraction 
technique was studied and numerous research paper 
concerning extraction of different natural products 
have been published [4-9].  In this papers, the 
influence of particular size and pressure to SFE of 
Salvia officinalis L. was investigated. 
 
2. Experiment 
 
Plant Material 
For this experiments Salvia officinalis L. from 
Berkovici, near Trebinje gathered in 2006 was used.  
 
Chemicals 
Commercial carbon dioxide (99% purity, Tehno–
gas, Novi Sad, Serbia) as the extracting agent was 
used. All other chemicals were of analytical reagent 
grade. 
Chromatographic procedures: 
MS, Finnigan – MAT 8230 BE geometry, 
resolution 1000, EI – CIU source at 200º. EI 70 eV, 
0.5 mA; CI, 1 mtorr of isobutane 150 eV 0.2 mA. 
GC/MS, Varian 3400 GC equipped with 
Split/Splitless injector (1:99) operated at 244°. 
Column J&W Scientific DB-5ms-ITD 30m, 
0.25mm id, 0.25μm film. Carrier gas hydrogen, l 
ml/min measured at 210°. Column temperature was 
linearly programmed from 40° to 285° at 4.3°/min. 
Transfer line at 270°, coupled to Finnigan-MAT 
8230 BE mass spectrometer. Ion source temperature 
170O, EI, 70eV 0.1 mA. Scan range 33-333 / 1 sec. 
GC, HP5890 series II 3400 GC equipped with 
Split/Splitless injector (1:99) operated at 244°. 
Column J&W Scientific DB-5ms-ITD 30m, 
0.25mm id, 0.25μm film. Carrier gas hydrogen, l 
ml/min measured at 210°. Column temperature was 
linearly programmed from 40° to 285° at 4.3°/min. 
 
Supercritical Fluid Extraction 
SFE by CO2 was carried out with a laboratory – 
scale high – pressure extraction plant (NOVA – Swiss, 
Effretikon, Switzerland). The main parts and 
characteristics (manufacturer specification) of the 
plant were as follows: a diaphragm – type compressor 
(up to 1000 bar), extractor with an internal volume of 
200 mL (Pmax = 250bar), and maximum CO2 mass flow 
rate of approximately 5.7 kg/h. 
 The mass of Salvia sample in extractor was 60g at 
the investigated value of pressure and at 40ºC, and the 
CO2 flow rate was 97.72 dm3/h. Separator conditions 
were 15 bar and 25ºC. 
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THE ANNALS OF “DUNAREA DE JOS” UNIVERSITY OF GALATI. 
FASCICLE IX. METALLURGY AND MATERIALS SCIENCE 
N0. 1 – 2008, ISSN 1453 – 083X 
 
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Fig. 3. Laboratory scale  high pressure SFE  plant 
 
3. Results and Discussion 
 
The supercritical fluid extraction (SFE) of Salvia 
officinalis L. by carbon dioxide (CO2) was 
investigated. Firstly, supercritical extraction of Salvia 
officinalis L was performed at different particles size, 
all other extraction conditions  were the same     
(Table 1). 
 
Table 1. Conditions for supercritical extraction by different particles size 
Sample 
Particle 
diameter size 
(mm) 
Extraction 
time  
(h) 
Flow rate of 
carbon dioxide 
(kg/min) 
Temperature 
(ºC) 
Pressure 
(bar) 
F1 0.21 4 3.225·10-3 40 100 
F2 0.43 4 3.225·10-3 40 100 
F3 1.13 4 3.225·10-3 40 100 
 
0 
0,5 
1 
1,5 
2 
2,5 
3 
3,5 
yi
el
d 
of
 e
xt
ra
ct
 (g
/1
00
g 
dr
ug
) 
F1 F2 F3
Sample
 
 Fig. 4. Yield of extract for different particles diameter size 
 
It was found that yield of extracts increases as 
particle diameter size decreases.  
 
The relative contents identified compounds of 
SC-CO2 extracts are given in table 2.  
 
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FASCICLE IX. METALLURGY AND MATERIALS SCIENCE 
N0. 1 – 2008, ISSN 1453 – 083X 
 
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Table 2. Composition of Salvia extract for different  particle size 
Sample 
Number Rt (min) Compound F1 F2 F3
 
Ik
1 10.902 α – thujone (cis) 2.7013 0.5419 0.2741 1102.7 
2 12.188 camphor 10.7024 - - 1138.4 
3 12.998 Isoborneol 9.6996 9.1258 6.2918 1162.8 
4 13.274 Terpineol L-4 1.7389 1.2051 0.6254 1169.7 
5 16.771 Bornyl acetate 4.3975 4.9818 2.0299 1268.1 
6 16.828 Sabinyl acetate 2.7628 0.5966 - 1274.4 
7 20.983 Isocaryophyllene 1.5904 1.7771 1.0393 1389.1 
8 21.554 α - gurjunene 0.5673 0.5612 0.4568 1406.8 
9 22.088 γ - elemene 11.3822 15.6045 9.8248 1424.9 
10 26.156 Selina–3,7(11) diene 13.6412 20.4167 18.9666 1559.9 
11 26.575 1,11-epoxyhumulene 3.9439 6.2998 5.7718 1573.1 
12 27.221 Caryophyllene oxide 2.3676 3.2769 2.9539 1595.4 
13 37.777 phyllocladene 21.6559 28.5225 38.8671 1995.1 
total 87.2 92.9 87.1  
Rt = chromatographic retention time 
 
In supercritical extract obtained for different 
particle size, 13 compounds were identified, with 
major compounds being: isoborneol, γ – elemene, 
Selina–3,7(11) diene and phyllocladene. 
The higest persentage phyllocladene is in sample 
F3 (38.87%), Selina–3,7(11) diene and β - elemene in 
sample F2 (20.42%; 15.60%).  
 
 
Fig. 5. GC chromatogram of Salvia extract (sample F1) 
 
Figurе 6 ilustrates the effects extraction time to 
yield of Salvia extract for different particle size.  
Extraction rate rapidly increased in first 90 
minute, and for farther extraction slowly increased.  
 
 
Effect particle size to yield of extract is small. 
Now, SFE  was performed at different pressure (80, 
100, 150, 200 and 300 bar), all other extraction 
conditions were the same( Tabele 3). 
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THE ANNALS OF “DUNAREA DE JOS” UNIVERSITY OF GALATI. 
FASCICLE IX. METALLURGY AND MATERIALS SCIENCE 
N0. 1 – 2008, ISSN 1453 – 083X 
 
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0 
0,5 
1 
1,5 
2 
2,5 
3 
3,5 
0 0,5 1 1,5 2 2,5 3 3,5 4 4,5 
extraction time (h)
d2
d1
yi
el
d 
of
 e
xt
ra
ct
 (g
/1
00
g 
dr
ug
) 
       d3
 
Fig. 6. Yield of extract vs.  extraction time for different particle size 
 
 
Table 3. Conditions for supercritical extraction by different pressure 
Sample 
Mean particle 
diameter 
(mm) 
Extraction 
time (h) 
CO2 flow rate 
(kg/min) 
Temperature 
(ºC) 
Pressure 
(bar) 
F4 0.3157 4 3.225·10-3 40 80 
F5 0.3157 4 3.225·10-3 40 100 
F6 0.3157 4 3.225·10-3 40 150 
F7 0.3157 4 3.225·10-3 40 200 
F8 0.3157 4 3.225·10-3 40 300 
 
 
0 
0,5 
1 
1,5 
2 
2,5 
3 
3,5 
4 
4,5 
5 
yi
el
d 
of
 e
xt
ra
ct
 (g
/1
00
g 
dr
ug
) 
F4 F5 F6 F7 F8Sample  
 
Fig.  7. Yield of extract for different pressure values 
 
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THE ANNALS OF “DUNAREA DE JOS” UNIVERSITY OF GALATI. 
FASCICLE IX. METALLURGY AND MATERIALS SCIENCE 
N0. 1 – 2008, ISSN 1453 – 083X 
 
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Table 4.  Composition of Salvia extract for different  pressure 
 
Sample 
 Num. Rt (min) Compound F4 F5 F6 F7 F8
1 10.870 α – thujone 0.663 4.445 4.183 3.769 5.153 
2 11.901 ß – thujone - - 0.1952 0.7016 - 
3 12.175 Camphor 1.433 11.929 11.372 14.877 15.239 
4 13.001 Isoborneol 11.287 7.389 6.804 9.523 8.167 
5 13.214 Terpineol L-4 2.081 0.321 0.248 0.332 0.298 
6 16.769 Bornyl acetate 5.905 3.586 2.015 4.621 3.959 
7 16.946 Sabinyl acetate 1.053 0.534 0.406 0.643 0.421 
8 20.979 Isocaryophyllene 2.745 1.179 0.839 1.300 1.168 
9 21.549 α – gurjunene 1.448 0.544 0.439 0.621 0.549 
10 22.085 γ – elemene 24.982 9.309 7.018 9.731 9.001 
11 26.155 Selina-3,7 (11) diene 11.253 12.168 13.827 12.507 12.141 
12 26.574 1,11-epoxyhumulene 8.989 4.557 5.869 4.958 4.921 
13 27.220 caryophyllene oxide 2.755 2.662 2.640 2.390 2.456 
14 37.783 Phyllocladene 10.420 26.056 30.645 21.990 24.603 
Total 85.0 84.7 86.5 88.0 88.1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Fig.  8. GC chromatogram of Salvia extract (sample F5) 
 
Fig. 9 ilustrates the effects extraction time to yield 
of Salvia extract for different pressure. Extraction rate 
rapidly increased in the first 90 minutes, and for 
farther extraction slowly increased. Effect  to yield of 
extract is more different for pressure p = 80bar from 
other pressure. In supercritical extract obtained for 
different pressure, 14 compounds were identified, with 
major compounds being: isoborneol, γ–elemene, 
Selina–3,7(11) diene and phyllocladene.The higest 
persentage phyllocladene (30.6%), and  Selina–
3,7(11) diene (13.8%) is in sample F6 and γ - elemene 
in sample F4 (24.98%).  
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THE ANNALS OF “DUNAREA DE JOS” UNIVERSITY OF GALATI. 
FASCICLE IX. METALLURGY AND MATERIALS SCIENCE 
N0. 1 – 2008, ISSN 1453 – 083X 
 
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0  
0,5  
1  
1,5  
2  
2,5  
3  
3,5  
4  
4,5  
5  
0  1  2 3 4 5  
 time (h) 
yi
el
d 
of
 e
xt
ra
ct
 (g
/1
00
g 
dr
ug
) 
  
80 bar 
100 bar 
150 bar 
200 bar 
300 bar 
Fig.  9. Yield of extract vs.  extraction time for different pressure 
 
4. Conclusions 
 
As expected from the studies on Salvia officinalis, 
the main compounds in extract are camphor, 
isoborneol, γ – elemene, selina – 3,7 (11) – diene and 
phyllocladene.The composition of main compounds 
in supercritical extract is not largely influenced by 
extraction pressure, exception pressure p=80bar. 
Indeed, chemical analysis of sage extract at different 
pressures evidenced composition variations along the 
extraction process but it they are not too large. The 
composition of main compounds in extract at pressure 
p=80 bar is largely different from composition at 
other pressures. 
In the first 90 minutes of extraction, yield of 
extract rapidly increased, and for father extraction 
yield of extract slowly increased. 
The five most abundant compounds (camphor, 
isoborneol, γ – elemene, selina – 3,7 (11) – diene, 
phyllocladene) represent  66.851 % of the extract 
(sample F5). 
 
 
 
 
 
 
 
References 
 
[1]. Stahl, E. , Quirin, K. –W., Gerard, D. Verdichtete, 1987, 
Case zur Extraktion und Raffination; Springer Verlag; Berlin 
[2]. Reverchon, E., Schiraldi, A., Fantozzi, P., 1993, Fluidi 
Supercritici, Applicazioni AgroAlimentari; CNR RAISA; Rome,. 
[3]. Reverchon, E., Senatore, F. J.; Agric. Food Chem. 1994, 42, 
154 
[4]. Zeković, Z.;  Lepojević, Ž.; Vujić Đ., 2000, Supercritical 
Extraction of Thyme (Thymus vulgaris L.) Chromatographia, 51 
(3/4), 175 
[5]. Zeković, Z., Lepojević, Ž, Milošević, S. , Tolić A., 2001, 
Thyme (Thymus vulgaris L.) compounds in SFE. Proceedings 6th 
Conference on Supercritical Fluids and Their Applications, Maiori, 
Italy, September, 9/110, 209 
[6]. Zeković Z, Lepojević, Ž., Tolić, A., 2001, Modelling of the 
Thyme – Supercritical Carbon Dioxide. Extraction System; Ithe 
influence of Carbon Dioxide Flow Rate and grinding degree of 
Thyme. Sep. Sci. Technol. 36 (15), 3459 
[7]. Aleksovski, S., Sovova, H., Poposka, F., 1998, Curapova, B. 
Supercritical fluid extraction of essential oils from peppermint and 
wild thyme and its comparison with hydrodistillation. XIII CHISA 
’98 (13 th International Congress of Chemical and Process 
Engineering), Praha, Aug 23 – 28, Summaries 4, 118 
[8]. Reverchon, E., 1997, Supercritical fluid extraction and 
fractionation of essential oils and related products, Journal of 
Supercritical Fluids, 10, 1 – 37 
[9]. Reverchon, E., Senatore, F., Isolation of rosemary oil: 
Comparision between hydrodistillation and supercritical CO2 
extraction. Flavour and Fragrance Journal, 7, 227-230.   
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Influence pressure and size particle to extraction by CO2

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Influence pressure and size particle to extraction by CO2

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