Direct Solvent Extraction Method Research Articles

Optimization of solvent extraction and HPLC-DAD method parameters for determination of phenolic compounds in various Brazilian propolis

Propolis is an organotherapeutic product collected by honey bees that contains a large number of phytoconstituents, possessing excellent pharmacological properties. In this study, phenolic composition and antioxidant capacity were evaluated in different types of Brown, Green and mixture of Red, Green I and Brown II (RGB) Brazilian propolis. Ultrasonic-assisted extraction was performed by direct solvent extraction (DSE) and successive solvent extraction (SSE) methods. The ethanolic extract of Green I propolis by SSE was higher in total phenolics (403.88 mg GAE/g extract), flavonoids (311.57 mg QE/g extract), and DPPH· scavenging activity (82.33 µMol TE/g extract) compared to other Brazilian propolis samples. Moreover, different solvent phases were used in the HPLC-DAD analysis and the results were validated by linearity and sensitivity. The optimized method was proven to be precise revealing good separation of standard phenolic compounds. Thermal stability of the compounds was accessed by using different column oven temperatures (40, 50 and 60 °C), and the results showed that lower temperature (40° C) retains the maximum contents of total phenolics in the 80% ethanolic extract of Green I propolis (253.71 mg/g extract) by DSE compared to other propolis samples. This extract (109.35 mg/g extract) also obtained a higher amount of total phenolic compounds in the SSE compared to ethyl acetate and acetone extracts. Among the phenolic compounds, artepillin C (60.10 mg/g extract) was higher in the SSE of Green I propolis 80% ethanolic extract. Thus, this study optimized the extraction and HPLC analytical conditions for the determination of phenolic composition and antioxidant capacity in different samples of Brazilian propolis.

Effects of Ultrasound-Assisted and Direct Solvent Extraction Methods on the Antioxidant and Antibacterial Properties of Saffron (Crocus sativus L.) Corm Extract

In this study, the response surface methodology (RSM) based on a central composite face-centered design (CCD) was used to optimize the extraction of bioactive constituents from Crocus sativus corms. The ultrasound-assisted extraction (UAE) was compared with the conventional direct solvent extraction (DSE) procedure. The optimum conditions of ethanol (80%), 48 °C and 60 min in DSE, and ethanol (80%), 37 °C, 45 min, and 37 kHz in UAE, were determined to receive extracts with maximum antioxidant activity and total phenolic content (TPC). The results showed TPC values of 89.28 and 100.39 (mg gallic acid equivalents in 100 g dry saffron corm) and total flavonoid contents (TFC) of 0.912 and 1.558 (mg quercetin equivalents in100 g dried saffron corm) for the optimized DSE and UAE extracts, respectively. The GC-MS analysis showed n-hexadecanoic acid as one of the main non-polar constituents in the saffron corm extract (39.315% and 19.015% in DSE and UAE extracts, respectively). The disc diffusion tests revealed a degree of activity of saffron corm extracts against Staphylococcus aureus at a minimum concentration of 300 mg/mL.

Rapid Analysis of 2-Alkylcyclobutanones in Irradiated Meats, Cheese and Salmon by Direct Solvent Extraction Followed by GPC

2-Alkylcyclobutanones (2-ACBs) are recognized as a marker of irradiation in lipid-containing food products. Here, a rapid method for the analysis of 2-dodecylcyclobutanone (2-DCB) and 2-tetradecylcyclobutanone (2-TCB) in irradiated food products using direct solvent extraction (DSE) was developed, and the extraction efficiency was compared to that of the Soxhlet extraction method (EN 1785), which is the official method for this analysis. Briefly, 2-ACBs were extracted either by using a Soxhlet apparatus or by DSE with n-hexane. The lipid extract was purified by GPC followed by a silica gel cartridge column. Finally, 2-DCB and 2-TCB were measured using GC-MS/MS. The extraction efficiency of 2-ACBs by the DSE method was similar to that of the Soxhlet extraction method. The trueness of 2-DCB and 2-TCB spiked at 50 ng/g in lipid extracts of beef, pork, chicken, cheese and salmon with the proposed method were 76.6% to 91.6% and 81.3% to 109.0%, respectively. The limits of detection for 2-DCB and 2-TCB in lipid extracts were 15 and 20 ng/g, respectively.

A Rapid Direct Solvent Extraction Method for the Extraction of 2‐Dodecylcyclobutanone from Irradiated Ground Beef Patties Using Acetonitrile

The amount of irradiated beef in the U.S. market is growing, and a reliable, rapid method is needed to detect irradiated beef and quantify the irradiation dose. The official analytical method (BS EN 1785 2003) that has been adopted by the European Union is time consuming. The objective of this study was to develop a rapid method for the analysis of 2-dodecylcyclobutanone (2-DCB) in irradiated beef. A 5 g sample of commercially irradiated ground beef patty (90/10) was extracted with n-hexane using a Soxhlet apparatus or with acetonitrile via direct solvent extraction. The Soxhlet hexane extract was evaporated to dryness, and the sample was dissolved in a mixture of ethyl acetate and acetonitrile (1:1). The defatted extract was purified with a 1 g silica cartridge. Another 5 g aliquot of the same patty was mixed with 50 mL acetonitrile and either blended for 1 min with a hand blender or crushed for 10 min with a glass rod. The extraction procedure was repeated 3 times, and the acetonitrile was collected and evaporated to dryness. Eluants from both methods were concentrated under nitrogen and injected into a gas chromatography-mass spectrometry. The 2-DCB concentration in the commercial samples was 0.031 +/- 0.0026 ppm (n = 5) for the Soxhlet method and 0.031 +/- 0.0025 ppm (n = 10) for direct solvent extraction. Recovery of 2-DCB from spiked beef samples in the direct solvent extraction method was 93.2 +/- 9.0% (n = 7). This study showed that the direct solvent extraction method is simple and as efficient and reproducible as the Soxhlet method.

Inter-laboratory Trial to Validate the Direct Solvent Extraction Method for the Identification of 2-dodecylcyclobutanone in Irradiated Chicken and Whole Liquid Egg

The main objective of this interlaboratory trial was to assess the qualitative performance of new rapid direct solvent extraction (DSE) method as potential detection method to differentiate between irradiated and unirradiated food samples. The trial was designed and carried out between four European laboratories that agreed to use 2-dodecylcyclobutanone (DCB) as radiolytic marker to detect irradiated minced chicken and liquid whole egg. Chicken samples were irradiated at 3 and 7 kGys while egg samples were irradiated at 3 and 6 kGys. Every laboratory had received 12-blind coded `unknown' and 4-known coded samples to be analyzed. All four laboratories were able to correctly identify all 12-blind coded samples as either irradiated (at medium and/or high doses) or unirradiated samples. The tested DSE method is regarded as fast, cheap, suitable and recommended for use in laboratories which are involved in screening large number of food samples for irradiation.

Extraction and identification of cyclobutanones from irradiated cheese employing a rapid direct solvent extraction method

2-Alkylcyclobutanones (cyclobutanones) are accepted as chemical markers for irradiated foods containing lipid. However, current extraction procedures (Soxhlet–florisil chromatography) for the isolation of these markers involve a long and tedious clean-up regime prior to gas chromatography–mass spectrophotometry identification. This paper outlines an alternative isolation and clean-up method for the extraction of cyclobutanones in irradiated Camembert cheese. The newly developed direct solvent extraction method enables the efficient screening of large numbers of food samples and is not as resource intensive as the BS EN 1785:1997 method. Direct solvent extraction appears to be a simple, robust method and has the added advantage of a considerably shorter extraction time for the analysis of foods containing lipid.

A rapid direct solvent extraction method for the extraction of cyclobutanones from irradiated chicken and liquid whole egg

Summary2‐Alkylcyclobutanones (cyclobutanones) are accepted as radiolytic markers in lipid‐containing foods (LCF). To date, cyclobutanones have not been detected in non‐irradiated foods. Their identification is the basis of a standardised detection test for irradiated LCF (BS EN 1785, 2003). This paper reports work to develop and refine a new rapid method for the analysis of cyclobutanones in irradiated LCF (e.g. chicken meat and liquid whole egg). Direct solvent extraction (DSE) enables the efficient screening of large numbers of food samples and is not as resource intensive as the BS EN 1785 (2003) method. The new DSE appears to be a promising, rapid, simple and robust method for the analysis of irradiated lipid‐containing foods.

Identification and quantification of methyl nicotinate in rice ( Oryza sativa L.) by gas chromatography–mass spectrometry

During the course of analysis of popular rice varieties cultivated in India towards identification of their aroma compounds, methyl nicotinate (MN), a medicinal and flavour additive compound, was identified for the first time in rice samples. A simple direct solvent extraction method using 300 mg of the sample is developed to extract MN in rice samples and detected by capillary gas chromatography–mass spectrometry analysis. Quantitative analysis of MN is performed for polished rice, brown rice and rice bran samples from five rice varieties that are widely produced in India by using GC–MS operating under SIM mode ( m/ z 106). The quantity of MN is in the range of 0.63–1.30 μg/g, 1.37–3.99 μg/g and 1.87–12.04 μg/g for polished rice, brown rice and rice bran samples, respectively. Breeding programmes for rice with high concentrations of MN can be greatly facilitated by establishing the concentrations of the MN in new cultivars. This method is more economic with less time consumption and enables fast screening of a large number of samples.

A small-scale sample preparation method with HPLC analysis for determination of tocopherols and tocotrienols in cereals

A small-scale sample preparation method was developed for reliable and economic analysis of tocopherols and tocotrienols in rye and other cereals. The saponification parameters were optimized using two experimental design protocols with statistical analyses. Three critical factors were optimized for hot saponification: time, temperature and amount of potassium hydroxide (KOH). The amount of KOH had the greatest effect. Two direct solvent extraction methods without saponification were tested and found to yield in comparable values than with saponification. Finally, three solvent mixtures for extracting tocopherols and tocotrienols after the optimized saponification step were studied in order to examine the effect of solvent polarity on their recovery. Adding a polar modifier to the solvent, tocopherol and tocotrienol values of rye were significantly increased. The optimized sample preparation method included saponification with 0.5 mL KOH at 100°C for 25 min followed by extraction with n-hexane:ethyl acetate (8:2). The repeatability of the recommended analytical procedure was good and the recoveries of added tocopherols from rye flour samples ranged from 90.3% to 94.3%. The procedure developed was applied to examine the amounts and distribution of tocopherols and tocotrienols in ten rye varieties. The average total tocopherol and tocotrienol content of rye grains was 48.8 μg/g with a 9.3% standard deviation between varieties.

A rapid procedure for analysing rice bran tocopherol, tocotrienol and γ-oryzanol contents

Tocopherols, tocotrienols and γ-oryzanol compounds are phytochemicals with antioxidant activities and potential health benefits. Their contents and isomer ratios in rice bran vary among southern US cultivars, suggesting that breeding for higher contents or a favorable ratio of these phytochemicals is feasible. Methods that can rapidly and reliably extract and quantify their contents in rice bran or whole rice kernel are necessary for breeding programs. A simple, one-step equilibrium extraction procedure coupled with reversed-phase (RP) HPLC is presented here. The one-min equilibrium extraction at a 1:60 (w/v) ratio of rice bran to methanol recovered 92 to 102% of the target phytochemicals relative to those of repeated, non-saponified, direct solvent extraction methods. At this 1:60 ratio of bran to solvent, isopropanol and methanol are superior extraction solvents relative to hexane. A modified, mobile-phase gradient with 10% of aqueous phase for the first 3-min eliminates all the methanol-soluble interfering compounds. This extraction method has the following advantages over the currently available methods: speed, no special extraction instrumentation is needed; and the extraction solvent, methanol, is compatible with subsequent quantification via RP-HPLC.

Stability of Tocopherols and Retinyl Palmitate in Snack Extrudates

ABSTRACT: Fish‐ and peanut‐containing half‐products were obtained by extruding and drying tocopherol‐ and retinyl palmitate‐fortified mixtures of tapioca starch and minced fish or partially defatted peanut flour (PDPF 60:40, wet basis). Half‐products were puffed by deep‐fat frying. Vitamins were determined simultaneously at each step of snack production using a direct solvent extraction method. Extrusion significantly reduced the content of tocopherols and retinyl palmitate in both products. Reduction of retinyl palmitate in fish and peanut extrudates during snack production was 48% and 27%, respectively. Final products contained more tocopherol than intermediates because of the high tocopherol content in the frying oil and its uptake.

Rapid Liquid Chromatographic Assay of Vitamin E and Retinyl Palmitate in Extruded Weaning Foods

ABSTRACTExtruded weaning foods were produced using cowpea + corn + soybean + soybean oil (35:50:10:5, w/w) and cowpea + corn + peanut (42:43:15, w/w) by twin screw extrusion and fortified with vitamin premix. A direct solvent extraction method was used to assay fortified α‐tocopheryl acetate as the ester to differentiate it from the naturally occurring alcohol for accurate assessment of total vitamin E activity. The fortified retinyl palmitate was assayed from the same extraction and assayed as the more stable ester with the same LC conditions after changing the detection wavelengths. Using direct solvent extraction, analytical values of vitamin E homologs in extruded products were higher than those values from saponification.

Extraction Method for Analysis of PAHs in Coal-Tar-Contaminated Soils

A direct solvent-extraction method was evaluated to assess its application for the extraction and analysis of PAHs (polycyclic aromatic hydrocarbons) in coal-tar-contaminated soils. Eight individual solvents and two combined solvents were used in a screening test to determine the suitability of different solvents for the direct solvent-extraction method. Based on the extracted concentrations of the Total PAH, noncarcinogenic PAH (N-PAH), and carcinogenic PAH (C-PAH), three different solvents—acetone, ethanol, and methylene chloride—were selected for further investigation by testing these solvents on four coal-tar-contaminated soils and a certified PAH-contaminated soil. The extraction results for the Total PAH and N-PAH concentrations showed that there were no statistical differences for the three solvents at a confidence interval of 95%. However, ethanol gave lower concentrations of C-PAH than acetone and methylene chloride. Fifteen coal-tar-contaminated soil samples from a land farming treatment unit were used to compare the direct solvent-extraction method using acetone as the extraction solvent with the conventional Soxhlet extraction method (EPA Method 3540) and ultrasonic extraction method (EPA Method 3550). The results showed that the direct solvent-extraction method gave higher mean PAH concentrations than the Soxhlet and ultrasonic extraction method and that the direct extraction method was equivalent to the Soxhlet method at a confidence interval of 99%. Because of its simplicity of use and its equivalent extraction capability with the Soxhlet extraction method, the direct solvent-extraction method may be used as a technique for the extraction and analysis of PAHs in contaminated soil.

Comparison of Sample Preparation Methods for the Analysis of Volatile Organic Compounds in Soil Samples: Solvent Extraction vs Vapor Partitioning

Presently, both direct vapor partitioning and solvent extraction methods of sample preparation are commonly used for the characterization of volatile organic compounds (VOCs) in soil. These two approaches of recovering VOCs from this matrix, and other forms of solid waste, are often used interchangeably without any recognition of how different parameters (enviromental and procedural) influence their performance. Three vapor partitioning headspace and three solvent extraction methods of preparing soil samples for the determination of VOCs were compared, without being confounded by volatilization or biodegradation losses. Soil samples were spiked with five aromatic and four chlorinated compounds using two different laboratory procedures. Recovery efficiencies for the preparation methods tested depended on soil organic carbon content, the octanol−water partition coefficients of specific analytes, and the duration of solvent extraction. Overall, methanol extraction was the most efficient and robust method for recovering spiked VOCs. Recovery of VOCs with tetraethylene glycol dimethyl ether and poly(propylene)glycol, as well as three vapor partitioning headspace methods, were frequently less than that obtained with methanol.

Headspace Gas Chromatography Profiles of Fruit-Flavored Malt Beverages Using Solid-Phase MicroExtraction

A solid-phase microextraction (SPME) headspace sampling technique has been applied to the gas chromatographic (GC) analysis of fruit-flavored malt beverages. The procedure provides an alternative to direct headspace, solvent extraction, and purge and trap methods for the monitoring of volatile components. The sampling technique is readily adapted to most capillary gas chromatographic systems with flame ionization detectors (FID). Over 40 components were identified by mass spectroscopy (MS) and monitored by GC-FID to evaluate 14 products containing raspberry, cherry, apple, and apricot flavors. Control of sample temperature and volume as well as SPME fiber position were important factors in obtaining consistent responses required for quantitation. Further application of this technique to monitor volatiles in unflavored beers and malt beverages is apparent.

Comparison of Extraction Methods for Methamphetamine and its Metabolites in Tissue

Five extraction methods were examined for analysis of methamphetamine and its major metabolites in tissue samples. The extraction methods studied were an acetone extraction method, an ethanol extraction method, an ammonium sulfate method, dialysis, and a direct solvent extraction. Acetone, ethanol, and dialysis methods showed no interference from endogenous components using thin-layer chromatography and gas chromatography, and gave satisfactory recovery of methamphetamine, amphetamine, and p-hydroxymethamphetamine when added to rabbit liver. These methods, however, proved time-consuming. The ammonium sulfate method and direct solvent extraction method were simple and more rapid, but recovery of the polar metabolite was poor.

Changes in Volatile Sulfur Compounds of Whisky During Aging

ABSTRACTVolatile sulfur compounds of malt whiskies were analyzed using a gas chromatograph equipped with a flame photometric detector by direct injection and solvent extraction methods. Sulfur compounds identified by coupled gas chromatography‐mass spectrometry and by matching GC retention times were dimethyl sulfide, dimethyl disulfide, dimethyl trisulfide, 3‐(methylthio)propanal, 3‐(methylthio)propanol, 3‐(methylthio)propyl acetate, ethyl 3‐(methylthio)‐propanoate, dihydro‐2‐methyl‐3(2H)‐thiophenone, 2‐thiophene‐carboxyaldehyde, 5‐methyl‐2‐thiophenecarboxaldehyde, benzothiophene and benzothiazole. Quantitative changes in these volatile sulfur compounds were studied by analyzing 48 aged and unaged malt whiskies by these methods. Dimethyl sulfide, 3‐(methylthio)propyl acetate, dihydro‐2‐methyl‐3(2H)‐thiophenone and ethyl 3‐(methylthio)propanoate decreased rapidly during aging and disappeared within three years. Dimethyl disulfide decreased gradually during aging. Dimethyl disulfide proved to be formed during distillation by the action of copper.

Sunflower processing technique

AbstractA great deal of interest has recently been shown in sunflower seed as an oilseed erop. The introduction of new Russian seed varieties with higher oil content have helped to stimulate this interest, particularly in the flax and cottonseed growing areas. This paper presents background material pertinent to the subject of sunflower processing. Such things as seed structure, oil and meal quality and certain economic considerations are included. Processing techniques currently used are discussed and comparisons made with the processing of other oilseeds. Brief mention is made of storage and handling of the seeds, meal and oil. Extraction is discussed briefly, but since it is successful only if the seed is properly prepared, seed preparation and handling prior to extraction are stressed. Sunflower seeds are nearly 30% hulls and these hulls are high in crude fiber content. For this reason, dehulling and hull separation practices are important aspects of processing sunflowers. Expeller operating variables are also important where prepressing is part of the process. These processes are stressed. Direct solvent extraction and prepress solvent extraction methods are currently being used successfully. Features of both methods and their applicability are discussed along with seed preparation needed for each method.