Supercritical fluid extraction combined with dispersive liquid-liquid microextraction as a sensitive and efficient sample preparation method for determination of organic compounds in solid samples

The supercritical fluid extraction (SFE) followed by the dispersive liquid-liquid microextraction (DLLME) has been developed for extraction and determination of polycyclic aromatic hydrocarbons (PAHs) in marine sediments. PAHs were employed as model compounds to assess the extraction procedure and were determined by gas chromatography-flame ionization detection (GC-FID). SFE of PAHs was performed at 313 K and 253.2 bar, at static and dynamic times 10 and 30 min, respectively. The extracted PAHs were collected in 1 mL of acetonitrile. Subsequently, 16 μL of chlorobenzene (as extraction solvent) was added to collecting solvent (1.0 mL of acetonitrile). Then, the resulted mixture was injected into 5.0 mL of aqueous solution, rapidly. After centrifugation, the PAHs in the sedimented phase were analyzed by GC-FID. Effects of significant parameters on the extraction in SFE and DLLME methods were investigated. Under the optimum conditions, the calibration plots were linear in the range of 0.4-41.6 mg kg⁻¹ and the limits of detection (LODs) were 0.2 mg kg⁻¹ for all of the analytes. Analysis of PAHs in different solid samples showed that the improved technique has great potential for PAHs analysis in marine sediments. SFE-DLLME leads to high preconcentration factor, easy use of DLLME in solid samples and solving the main problem of SFE that is the extra step (vaporization of large volume of toxic organic solvent) after extraction needed prior to final analysis.     

Determination of sudan dyes in food samples using supercritical fluid extraction-capillary liquid chromatography

Determination of sudan dyes (Sudan I, Sudan II, Sudan III and Sudan IV) in food samples has been developed by several and different methods. However, sample treatment continues being the most important problem to determine these compounds in real samples. A rapid, sensitive and selective method for the extraction, separation and quantification of sudan dyes in commercial food samples has been developed. The method is based on the combination of a supercritical fluid extraction (SFE) procedure, followed by the analysis of the extracted plug by capillary liquid chromatography (CLC) with diode array detection (DAD). The entire procedure was optimized for the extraction of the samples, separation and detection of the analytes. For the SFE, the effect of CO₂ flow rate, extraction pressure, extraction temperature, equilibration and extraction time and methanol modifier content were studied. Linear responses in the range from 50 to 1000 ng mL⁻¹ with average relative standard deviation lower than 11.6, and detection limits ranging from 23.2 to 42.0 ng mL⁻¹ were obtained for the different sudan dyes. The recoveries were in the range of 91-109% for dyes powder samples.     

Combination of supercritical fluid extraction with dispersive liquid-liquid microextraction for extraction of organophosphorus pesticides from soil and marine sediment samples

Supercritical fluid extraction (SFE) coupled with dispersive liquid-liquid microextraction (DLLME) and followed by gas chromatography-flame ionization detection (GC-FID) was applied for extraction and determination of ultra-trace amounts of seven organophosphorus pesticides (OPPs) (o,o,o-triethyl phosphorothioate, thionazin, sulfotepp, disulfoton, methyl parathion, parathion, and famphur) in soil and marine sediment samples. Supercritical CO₂ at 150 bar, 60 °C, 10 min static and 30 min dynamic extraction times was used to extract the pesticides. The extracts were collected in 1.0 mL of acetonitrile. Seventeen μL of carbon tetrachloride was dissolved in the collecting solvent and the mixture was then injected rapidly into 5.0 mL of aqueous solution. About (5.0 ± 0.2 μL) of sediment phase was collected after centrifuging and finally 2.0 μL of it was injected into gas chromatography (GC) injection port for analyses. The extraction recoveries for the target analytes were in the range of 44.4% and 95.4% and relative standard deviation (RSD%) for four-replicate measurements was below 7.5%. The limit detections of the method for determining the pesticides were in the range of 0.001-0.009 mg kg⁻¹. The method was successfully applied for analysis of OPPs in real soil and marine sediment samples and satisfactory results were obtained.     

Isolation of antioxidant catechins from green tea and its decaffeination

Ethyl acetate, n-butanol and n-hexane were used as solvents to separate catechins from green tea extract solution and the catechins were decaffeinated using citric acid solution. Ethyl acetate was confirmed to be an appropriate solvent for isolating catechins from tea extract, based on yield of catechins and concentrations of caffeine. The optimum extraction conditions were that 100 g tea was extracted in 3 L water at 80 °C for 40 min and the catechins in the extracted solution were isolated using 1.5 L ethyl acetate for three times. The extracted catechins in the ethyl acetate phase was then decaffeinated by washing the organic phase with 1.5 L of 10 g L⁻¹ citric acid solution for three times. The obtained product contained 694.47 mg g⁻¹ catehchins and 37.89 mg g⁻¹ caffeine, with 78.8% caffeine being removed. The method is considered to be an alternative to replace traditional chloroform decaffeination.     

A simple electroanalytical method for the analysis of the dye solvent orange 7 in fuel ethanol

The purpose of this paper is to develop a simple, rapid and accurate electroanalytical method for the determination of solvent orange 7 (SO-7), commercially used as a dye marker in fuel ethanol samples. SO-7 is oxidized in a mixture of Britton-Robinson buffer with N,N-dimethylformamide (1:1, v/v) at a glassy carbon electrode and presents a well-defined peak around +0.70 V vs. Ag/AgCl, which can be monitored by linear-scan voltammetry (LSV) and square-wave voltammetry (SWV). Using optimized parameters based on the SWV technique, it is possible to get a linear relationship between the peak current and the SO-7 dye concentration from 4.0 × 10⁻⁶ to 18.0 × 10⁻⁶ mol L⁻¹ (r = 0.995). The proposed method was successfully applied to the direct quantification of the SO-7 dye in fuel ethanol samples, which gave good average recovery for commercial samples containing 5.0 mg L⁻¹ and 10.0 mg L⁻¹ of SO-7 dye, respectively.     

A-type zeolite containing Ag/Zn as inorganic antifungal for waterborne coating formulations

The biocide cations Ag⁺ and Zn²⁺ were hosted in the cavities of an ordered aluminosiliceous framework. Starting from sodium A-type zeolite (NaA), LTA containing Ag⁺ (AgA), Zn²⁺ (ZnA) and Ag⁺/Zn (AgZnA) at different cation exchanged levels was obtained and its antifungal properties were evaluated. To determine the minimum inhibitory concentration (MIC) of the exchanged zeolites against Aspergillus niger, [Ag⁺] and [Zn²⁺] values ranging from 50 < [Ag⁺] < 1000 mg L⁻¹ to 650 < [Zn²⁺] < 2000 mg L⁻¹, respectively, were used for NaA, and for AgZnA: 30 < Ag⁺ < 250 mg L⁻¹. The zeolite sample having [Ag⁺] = 100 mg L⁻¹, [Zn²⁺] = 90 mg L⁻¹ produces a growth inhibition comparable to that achieved with 230 mg L⁻¹ of Ag⁺¹ (MIC value obtained for the single cation). The antifungal activity of these products after incorporation in waterborne coating formulations was also determined. Results indicate that Ag⁺ and Zn²⁺ supported on A-type zeolite could be a beneficial tool for the development of waterborne coatings with a longer protection against microbiological attack when compared to traditional organic biocides.     

Extraction of phenolic fraction from guava seeds (Psidium guajava L.) using supercritical carbon dioxide and co-solvents

In this work the supercritical fluid extraction (SFE) with carbon dioxide (CO₂) and with ethyl acetate (EtAc) and ethanol (EtOH) as co-solvents was applied to obtain the phenolic fraction from guava seeds (Psidium guajava L.). The extraction was explored at various operating conditions, using 10, 20 and 30 MPa and 40, 50 and 60 °C. The use of EtAc and EtOH as co-solvents in SFE was also studied. The supercritical process was compared with traditional techniques such as Soxhlet extraction using EtAc and EtOH as solvents. The quality of the different extracts, obtained using SFE and Soxhlet methods and different solvents, was evaluated through the antioxidant activity, obtained by the collection methods of scavenging DPPH and bleaching of β-carotene, and also through the total phenolic content (TPC) of the samples, by the Folin-Ciocalteu method. The antioxidant potential indicates the use of ethanol as co-solvent as the best modifier in SFE, used in concentration of 10% (w/w) at 50 °C and 30 MPa. The quality of the extracts obtained by SFE with EtOH varied with the operating conditions of temperature and pressure, with higher values obtained at 10 and 20 MPa for TPC results and also antioxidant methods. The process yield of the phenolic fraction was also evaluated for all the extraction procedures studied (SFE and Soxhlet), with results varying from 0.380 to 1.738% (w/w).     

Supercritical fluid extraction of wormwood (Artemisia absinthium L.)

The objective of the work was to optimize the extraction of wormwood oil by supercritical fluid extraction (SFE) of growth-controlled plant material. Different extraction conditions, two growth techniques and various crops were tested and the evolution of the extracted oil composition was screened chromatographically. A comparison with conventional techniques such as hydrodistillation (HD) or organic solvent extraction (OSE) was also presented. Particularly, six CO₂ densities ranging from 285.0 kg/m³ to 819.5 kg/m³ were studied in the range of 9.0-18.0 MPa and 40-50 °C. A systematic study was carried out with plant material from 2005, while SFE of 2006, 2008 and aeroponically grown crops was performed for comparative purposes. The effect of ethanol as a modifier of the supercritical fluid extraction was also studied. The major compounds found in the SFE extracts as well as in the HD essential oils were Z-epoxyocimene, chrysanthenol and chrysanthenyl acetate. A model based on mass transfer equations, the Sovová model, was successfully applied to correlate the experimental data.     

Catalytic adsorptive stripping voltammetric determination of Cr(VI) in EDTA extracts from solid samples

A catalytic adsorptive stripping voltammetric procedure which allows for Cr(VI) determination in EDTA extracts is presented. EDTA used for extraction can be exploited as a masking agent for Cr(III). The calibration graph for Cr(VI) for an accumulation time of 60 s was linear in the range from 2 × 10⁻¹⁰ to 3 × 10⁻⁸ mol L⁻¹. The relative standard deviation for a Cr(VI) concentration of 2 × 10⁻⁹ mol L⁻¹ was 5.1% (n = 5). The detection limit estimated from three times the standard deviation of low Cr(VI) concentration and accumulation time of 60 s was about 7 × 10⁻¹¹ mol L⁻¹. The influence of foreign ions commonly present in extracts from solid samples is presented. The proposed voltammetric procedure was applied to determine Cr(VI) in EDTA extractable chromium from soil certified reference materials CRM 483 and CRM 041. The performance of the method was also verified by studying the recovery of Cr(VI) from spiked river water.     

Study on the electrochemical behaviour of the anticancer herbal drug emodin

The electrochemical behaviour of the anticancer herbal drug emodin was investigated by cyclic voltammetry (CV) at glassy carbon electrode. In 0.05 M NH₃-NH₄Cl (50% ethanol, pH 7.2) buffer solution, a pair of quasi-reversible redox peaks at potentials of Ep1 = −0.688 V and Ep2 = −0.628 V and one irreversible anodic peak, which was a typical anodic peak of emodin, at Ep3 = −0.235 V appeared at a scan rate of 100 mV/s. The irreversible anodic peak currents are linearly related to the emodin concentrations in a range from 8.9 × 10⁻⁸ M to 7.8 × 10⁻⁶ M with a pre-concentration time of 80 s under −0.620 V. Using the established method without pretreatment and pre-separation, emodin in herbal drug was determined with satisfactory results. Moreover, the electrode process dynamics parameters were also investigated by electrochemical techniques.     

On the performances of lead dioxide and boron-doped diamond electrodes in the anodic oxidation of simulated wastewater containing the Reactive Orange 16 dye

The performances of the Ti-Pt/β-PbO₂ and boron-doped diamond (BDD) electrodes in the electrooxidation of simulated wastewaters containing 85 mg L⁻¹ of the Reactive Orange 16 dye were investigated using a filter-press reactor. The electrolyses were carried out at the flow rate of 7 L min⁻¹, at different current densities (10-70 mA cm⁻²), and in the absence or presence of chloride ions (10-70 mM NaCl). In the absence of NaCl, total decolourisation of the simulated dye wastewater was attained independently of the electrode used. However, the performance of the BDD electrode was better than that of the Ti-Pt/β-PbO₂ electrode; the total decolourisations were achieved by applying only 1.0 A h L⁻¹ and 2.0 A h L⁻¹, respectively. In the presence of NaCl, with the electrogeneration of active chlorine, the times needed for total colour removal were markedly decreased; the addition of 50 mM Cl⁻ or 35 mM Cl⁻ (for Ti-Pt/β-PbO₂ or BDD, respectively) to the supporting electrolyte led to a 90% decrease of these times (at 50 mA cm⁻²). On the other hand, total mineralization of the dye in the presence of NaCl was attained only when using the BDD electrode (for 1.0 A h L⁻¹); for the Ti-Pt/β-PbO₂ electrode, a maximum mineralization of 85% was attained (for 2.0 A h L⁻¹). For total decolourisation of the simulated dye wastewater, the energy consumption per unit mass of dye oxidized was only 4.4 kWh kg⁻¹ or 1.9 kWh kg⁻¹ using the Ti-Pt/β-PbO₂ or BDD electrode, respectively. Clearly the BDD electrode proved to be the best anode for the electrooxidative degradation of the dye, either in the presence or absence of chloride ions.     

Radical-scavenging activity of extracts from Cordia verbenacea DC obtained by different methods

The possibility of using the leaves of Cordia verbenacea as a new source of natural antioxidant compounds was investigated. In the present work, extracts from C. verbenacea were obtained using different extraction methods: supercritical fluid extraction (SFE), Soxhlet (SE), hydrodistillation and maceration, with the objective to evaluate the methods in terms of yield and antioxidant potential. The high-pressure technique was applied using pure CO₂ and CO₂ with co-solvent at different temperatures and pressures (30, 40 and 50 °C and 100, 200, and 300 bar). Organic solvents with different polarities were used to obtain extracts by low-pressure extraction processes. The extracts were evaluated according to their antioxidant activity using total phenolic content, scavenging abilities on DPPH radical, total antioxidant activities (ABTS^•+), superoxide anion radical-scavenging (O₂^•) and protection against lipid peroxidation in vitro (LPO). Ethyl acetate fraction obtained by maceration and extract isolated by SE using 25% aqueous mixture of ethanol possessed the highest scavenger activity against DPPH radical (IC₅₀ = 9.2 ± 0.4 μg/ml, IC₅₀ = 27.4 ± 0.1 μg/ml, respectively). The SFE with 8% ethanol as a co-solvent produced extracts with distinguished increase in the antioxidant activity. The Soxhlet extract with ethyl acetate exhibited a strong reduction of lipid peroxidation (IC₅₀ = 209 ± 3 μg/ml) value comparable to the standard rutin (IC₅₀ = 203 ± 2 μg/ml). The results indicate that extracts of C. verbenacea have important potential as a source of bioactive compounds with antioxidant activity.     

Flat-plate submerged membrane bioreactor for the treatment of higher-load graywater

Graywater treatment has been the focus when topics of decentralized treatment systems are discussed. In this paper, the treatment of higher-load graywater, a mixture of washing machine and kitchen sink wastewater, was investigated. A 10 L lab-scale submerged membrane bioreactor (subMBR) was operated with a flat-plate membrane for 87 days. Permeate was intermittently withdrawn at constant transmembrane pressure (TMP) induced by water level difference and without pump requirement. The pollutants' removal and membrane behavior were monitored. The COD removal was around 96% and a permeate COD of about 26 mg L^− 1 was obtained. The total linear alkylbenzene sulfonate (LAS) removal achieved was > 99%, indicative of its non-inhibited degradation even at influent concentration of 30.8 mg L^− 1. The subMBR was operated at almost stable and constant flux of 0.22 m³ m^− 2 d^− 1 at a mean HRT of 13.6 h.     

Promethazine determination in plasma samples by using carbon paste electrode modified with molecularly imprinted polymer (MIP): Coupling of extraction, preconcentration and electrochemical determination

A promethazine (PMZ) molecularly imprinted polymer (MIP) and a non-imprinted polymer (NIP) were synthesized by two different formulations of methacrylic acid-ethylene glycol dimethacrylate (MAA-EGDMA) and vinyl benzene-divinyl benzene (VB-DVB). Then, the MIPs were used to modify the carbon paste electrode (CP). The response difference between MIP-CP and NIP-CP electrodes, containing VB-DVB polymer, was higher than that for MIP-CP and NIP-CP modified with polymer of MAA-EGDMA, indicating the lower nonselective surface adsorption property of the VB-DVB based MIP. The MIP, incorporated in the carbon paste electrode, functioned as selectively recognition element and pre-concentrator agent for PMZ determination. The prepared electrode was used for PMZ measurement by the three steps procedure including analyte extraction in the electrode, electrode washing and electrochemical measurement of PMZ. It was shown that the electrode washing, after PMZ extraction, led to enhanced selectivity. Square wave voltammetry (SWV) for PMZ determination by proposed electrode was proved to be better than that of differential pulse voltammetry. Some parameters, effective on the electrode response, were optimized and then a calibration curve was plotted. Two dynamic linear range of 7 × 10⁻⁹ to 4 × 10⁻⁷ and 4 × 10⁻⁷ to 7 × 10⁻⁶ mol L⁻¹ were obtained. The detection limit of the method was calculated equal to 3.2 × 10⁻⁹ mol L⁻¹. This method was used successful for PMZ determination in blood serum sample.     

Voltammetric determination of trace quantities of 6-thioguanine based on the interaction with DNA at a mercury electrode

Herein, a sensitive square wave voltammetric (SWV) method is described for the quantitative determination of an anticancer drug, 6-thioguanine (6-TG). The interaction of 6-TG with double stranded DNA (ds-DNA) in the solution phase resulted in a well amplified SWV response at the surface of hanging mercury dropping electrode (HMDE). Accumulation and stripping steps were made in the sample medium conditioned with acetate buffer (pH 4.8). Optimized conditions for the accumulation step included the deposition potential at −0.10 V, a deposition time of 30 s, a frequency of 50 Hz, a pulse amplitude of 20 mV, and a step potential of 7 mV. In the solution containing 2.0 mg L⁻¹ ds-DNA, determination was performed within a wide concentration range of 2.4 × 10⁻⁹ to 1.8 × 10⁻⁵ mol L⁻¹, and a detection limit of 2.1 nmol L⁻¹ 6-TG. An overall conclusion was that the intercalation of 6-TG into ds-DNA in a solution medium of the acetate buffer is a possible reason for the observed behavior. The method was applied for the determination of 6-TG in 6-thioguanine tablets and spiked blood serum samples. No statistically significant differences were observed between the expected and obtained concentrations. The new method is sufficiently sensitive to detect ultra trace amounts of 6-TG content.     

Development of a voltammetric sensor based on a molecularly imprinted polymer (MIP) for caffeine measurement

A new voltammetric sensor for caffeine measurement is introduced. A caffeine-selective molecularly imprinted polymer (MIP) and a non-imprinted polymer (NIP) were synthesized and then used for carbon paste (CP) electrode preparation. The MIP, embedded in the carbon paste electrode, functioned as a selective recognition element and a pre-concentrator agent for caffeine determination. The prepared electrode was used for caffeine measurement via a three-step procedure including analyte extraction in the electrode, electrode washing and electrochemical measurement of caffeine. The MIP-CP electrode showed very high recognition ability in comparison to NIP-CP. It was shown that electrode washing after caffeine extraction led to enhanced selectivity. Differential pulse voltammetry for caffeine determination was more effective than square wave voltammetry. Some parameters affecting sensor response were optimized, and a calibration curve was then plotted. A linear range of 6 × 10⁻⁸ to 2.5 × 10⁻⁵ mol L⁻¹ was obtained. The detection limit of the sensor was calculated to be equal to 1.5 × 10⁻⁸ mol L⁻¹. This sensor was used successfully for caffeine determination in spiked beverage and tea samples.     

Removal of Remazol Brilliant Blue R dye from aqueous solutions by adsorption onto immobilized Scenedesmus quadricauda: Equilibrium and kinetic modeling studies

The green algae Scenedesmus quadricauda was immobilized in alginate gel beads. The immobilized active (IASq) and heat inactivated S.quadricauda (IHISq) were used for the removal of Remazol Brilliant Blue R (CI 61200, Reactive Blue 19, RBBR) from aqueous solutions in the concentration range 25-200 mg L^− 1. At 150 mg L^− 1 initial dye concentration the IASq and IHISq exhibited the highest dye uptake capacity at 30 °C, at the initial pH value of 2.0. At the same initial dye concentration in the batch system the adsorption capacity was determined for IASq as 44.2; 44.9 and 45.7 mg g^− 1 in 30, 60 and 300 min, respectively. After 300 min the adsorption capacity hardly changed during the adsorption time. The IHISq of adsorption capacity was observed as 47.6; 47.8 and 48.3 mg g^− 1 in 30, 60 and 300 min, respectively. After 300 min the adsorption capacity was not changed for 24 h. The Langmuir, Freundlich, Temkin, Dubinin-Radushkevich and Flory-Huggins isotherm models were used to fit the equilibrium biosorption data. The Langmuir, Freundlich and Dubinin-Radushkevich equations have better coefficients than Temkin and Flory-Huggins equation describing the RBBR dye adsorption onto IASq and IHISq. The monomolecular biosorption capacity of the biomass was found to be 68 and 95.2 mg g^− 1 for IASq and IHISq, respectively. From the Dubinin-Radushkevich model, the mean free energy was calculated as 6.42-7.15 kJ mol^− 1 for IASq and IHISq, indicating that the biosorption of dye was taken place in physical adsorption reactions. The experimental data were also tested in terms of kinetic characteristics and it was determined that the biosorption process of dye was well explained with pseudo-second-order kinetics.     

Electrochemical sensor for sulfite determination based on a nanostructured copper-salen film modified electrode

The electrochemical preparation described herein involved the electrocatalytic oxidation of sulfite on a platinum electrode modified with nanostructured copper salen (salen = N,N′-ethylenebis(salicylideneiminato)) polymer films. The complex was prepared and electropolymerized at a platinum electrode in a 0.1 mol L⁻¹ solution of tetrabutylammonium perchlorate in acetonitrile by cyclic voltammetry between 0 and 1.4 V vs. SCE. After cycling the modified electrode in a 0.50 mol L⁻¹ KCl solution, the estimated surface concentration was found to be equal to 2.2 × 10⁻⁹ mol cm⁻². This is a typical behavior of an electrode surface immobilized with a redox couple that can usually be considered as a reversible single-electron reduction/oxidation of the copper(II)/copper(III) couple. The potential peaks of the modified electrode in the electrolyte solution (aqueous) containing the different anions increase with the decrease of the ionic radius, demonstrating that the counter-ions influence the voltammetric behavior of the sensor. The potential peak was found to be linearly dependent upon the ratio [ionic charge]/[ionic radius]. The oxidation of the sulfite anion was performed at the platinum electrode at +0.9 V vs. SCE. However, a significant decrease in the overpotential (+0.45 V) was obtained while using the sensor, which minimized the effect of oxidizable interferences. A plot of the anodic current vs. the sulfite concentration for chronoamperometry (potential fixed = +0.45 V) at the sensor was linear in the 4.0 × 10⁻⁶ to 6.9 × 10⁻⁵ mol L⁻¹ concentration range and the concentration limit was 1.2 × 10⁻⁶ mol L⁻¹. The reaction order with respect to sulfite was determined by the slope of the logarithm of the current vs. the logarithm of the sulfite concentration.     

Equilibrium and kinetic modelling of the adsorption of Cd ions onto chestnut shell

A study on the removal of Cd²⁺ ions from aqueous solutions by acid formaldehyde pretreated chestnut (Castanea sativa) shell was conducted in batch conditions. The influence of different parameters: adsorption time, temperature (15, 25 and 35 °C) and initial concentration of Cd²⁺ ions (15.3, 50.5 and 87.3 mg L^− 1), on cadmium uptake was analysed. Cadmium free and cadmium loaded chestnut shell were characterized by FTIR spectroscopy, which evidenced the functional groups involved in cadmium uptake. Cadmium adsorption equilibrium could be described by the Freundlich adsorption model at all the temperatures essayed, which predicted shell heterogeneity. The Cd²⁺ adsorption process by chestnut shell followed the pseudo second order kinetic model. Cadmium sorption capacity increased with decreasing temperature at an initial concentration of 15.3 mg L^− 1 and with increasing initial cadmium concentration at a temperature of 25 °C. The second order kinetic constant, which increased with increasing temperature, was used to calculate the energy of adsorption as equal to 19.2 kJ mol^− 1.     

Supercritical fluid extraction of lycopene from tomato juice and characterization of its antioxidation activity

A new method to extract lycopene from tomato juice using supercritical CO₂ as solvent and without the need to dry the raw material is presented. To conduct the extraction, the tomato juice was subjected to cycles of centrifugation followed by rinsing with absolute ethanol to partially remove the water present in the solid part of the juice. The influence of the temperature and pressure on the extraction efficiency and on the extract antioxidant activity was studied using a factorial experimental design. The extraction efficiency varied from 7.7% to 76.7% and only extraction temperature had a statically significant effect on the process. The reversed phase HPLC analysis showed that lycopene is the major compound of the extract. The extract that presented higher antioxidant activity was obtained at 40 °C and 350 bar with 12.7 mmol L⁻¹ Trolox/g of extract using the DPPH radical scavenging method and 61.3 mmol L⁻¹ Trolox/g of extract using the rubrene singlet oxygen quenching method.