Isopropanol In Hexane Research Articles

Incomplete lipid extraction as a possible cause for underestimation of lipid oxidation in emulsions

AbstractLipid oxidation deteriorates the sensory and nutritional quality of food emulsions containing polyunsaturated fatty acids. Classically, different extraction solvents are used as a first step to measure lipid oxidation in emulsions. However, it is unclear how the applied extraction method influences the measured lipid oxidation values. In this work, we systematically examined the performance of common solvent mixtures such as chloroform, methanol, and hexane (or isooctane)–isopropanol on lipid extraction from emulsions stabilized with different emulsifiers (Tween 20 (T20), whey proteins, and pea proteins) and oxidation levels, and how this, in turn, affected the measured hydroperoxide concentrations. Chloroform–methanol was the most effective solvent (lipid yield >93 wt.%). When using hexane–isopropanol, extraction yields were consistently high for T20‐ and pea protein‐based emulsions (>60 wt.%), but in whey protein‐based emulsions, values as low as 26 wt.% were measured. In case of incomplete extraction, hydroperoxide concentrations measured by colorimetric methods need to be corrected for this effect. When using 1H NMR to assess lipid oxidation, the actual amount of extracted lipids is intrinsically taken into account. This highlights not only the importance of the extraction method in determining lipid oxidation in emulsions but also that of the actual analysis method.Practical application: This study highlights that the lipid extraction yield can vary depending not only on the emulsion composition (e.g., type of emulsifier) but also on the oxidative state of the emulsion and the extraction solvent used. If this is overlooked, errors can be made in the hydroperoxide determination. Although these effects can be corrected for, this is not standard procedure, which implies that awareness on this matter should be increased. It is also important to point out that depending on the solvent used, the different lipid classes (including various lipid oxidation products) may be extracted at different levels. Chloroform–methanol should be preferred for extraction of all lipid and lipid oxidation‐derived molecules, including aldehydes.

Identification and Content of Astaxanthin and Its Esters from Microalgae Haematococcus pluvialis by HPLC-DAD and LC-QTOF-MS after Extraction with Various Solvents.

Haematococcus pluvialis, a unicellular green microalga that produces a secondary metabolite under stress conditions, bears one of the most potent antioxidants, namely xanthophyll astaxanthin. The aim of our study was to determine the content of astaxanthin and its esterified forms using three different solvents—methyl tert-butyl ether (MTBE), hexane isopropanol (HEX -IPA) and acetone (ACE)—and to identify them by using high performance liquid chromatography coupled with diode array detection and the quadrupole time-of-flight mass spectrometry (HPLC-DAD and LC-QTOF-MS) technique. We identified eleven astaxanthin monoesters, which accounted for 78.8% of the total astaxanthin pool, six astaxanthin diesters (20.5% of total), while free astaxanthin represented the smallest fraction (0.7%). Astaxanthin monoesters (C16:2, C16:1, C16:0), which were the major bioactive compounds in the H. pluvialis samples studied, ranged from 10.2 to 11.8 mg g−1 DW. Astaxanthin diesters (C18:4/C18:3, C18:1/C18:3) were detected in the range between 2.3 and 2.6 mg g−1 DW. All three solvents were found to be effective for extraction, but MTBE and hexane-isopropanol extracted the greatest amount of free bioactive astaxanthin. Furthermore, MTBE extracted more low-chain astaxanthin monoesters (C16), and hexane-isopropanol extracted more long-chain monoesters (C18 and above) and more diesters. We can conclude that MTBE is the solvent of choice for the extraction of monoesters and hexane-isopropanol for diesters.

Extraction of lipids from insect powders using a one-step organic solvent extraction process

The extraction efficiency, fatty acid profiles (FAP) and classes of lipids separated from insect powders by a one-step process were studied. Hexane (H), chloroform (C), methyl-tert-butyl ether (MTBE), and 3:2 hexane-isopropanol (HI) were used as extraction solvents and results were compared to 2:1 chloroform-methanol (CM). A 1:10 sample:solvent was mixed and centrifuged to separate the lipid layer which was then filtered and dried. Extraction was best (P<0.05) using CM as the solvent for adult cricket and locust; however, MTBE had the greatest efficiency (P<0.05) for silkworm pupae. The lipid classes extracted from silkworm were most like the initial powder (p>0.05), regardless of solvent. H and MTBE extracted lipid classes like (P>0.05) the initial cricket and locust, respectively. The FAP for cricket lipid was like the initial (P>0.05) when CM was used; however, the FAPs of locust and silkworm lipid were most like the initial powders (P>0.05) when MTBE and C were used as the solvent, respectively.

Interphase Distribution of Lanthanide Chlorides in Multicomponent Aqueous–Organic Two-Phase Systems Containing DEHPA

The interphase distribution of lanthanide chlorides in ternary aqueous–organic systems containing DEHPA has been studied as a function of the compositions of the aqueous and organic phases. It is found that, in a 1 : 1 : 1 ternary system (aqueous LaCl3 solution + CH3COONa + CH3COOH–DEHPA in hexane–isopropanol), one can achieve the separation of lanthanides, which depends on the ratio between sodium acetate and acetic acid in the aqueous phase and the DEHPA concentration in the organic phase. The separation coefficients of lanthanides with respect to lanthanum in the extraction of rare-earth metal chlorides from acetic acid–acetate solutions are calculated.

Outdoor cultivation of the green microalga Chlorella vulgaris under stress conditions as a feedstock for biofuel.

The present work investigated the potential of the green alga Chlorella vulgaris to produce high-quality biofuel under culture stress conditions. The cultivation was carried out in a 1000 lopen plate tank system, which provides biomass yields comparable to open pond systems, but with less area needed. Algal biomass and lipid content were measured repeatedly. We compared the two solvent systems n-hexane and hexane/isopropanol (HIP) for extraction efficiency of lipids and applied three different extraction methods Soxhlet, soaking, and soaking followed by Soxhlet (soak-Sox). The combination of the HIP solvent and the soak-Sox provided the highest lipid yield (15.8 ± 0.174). Volumetric biomass and lipid productivity were 0.201gl-1day-1 and 31.71mgl-1day-1, respectively, whereas areal biomass and lipid productivity were 25.73gm-2day-1 and 4.066gm-2day-1, respectively. The fatty acid profile by means of gas chromatography resulted in seven fatty acids from C12 to C18. The most abundant fatty acid methyl esters (FAMES) were palmitic (C16:0), oleic (C18:1), and stearic (C18:0) acids. Lipid synthesis enhanced by optimizing the Kuhl growth medium with replacing nitrate by urea (50% N compared to the original recipe) increased salt content (10g/l NaCl), ferrous sulfate (0.5g/l), and sodium acetate addition (1g/l). With regard to density, kinematic viscosity, gravity, pour point, flash point, and cetane number, the Chlorella-biodiesel comply with ASTM and EN standards thus pointing at the high potential of lipids synthesized by Chlorella as a feedstock for biodiesel production.

Optimization of Ultrasound-Assisted Extraction of Oil from Canola Seeds with the Use of Response Surface Methodology

In the current study, response surface optimization of canola oil extraction assisted by 35 kHz, 800 W ultrasound waves and with the use of hexane and 3:2 hexane–isopropanol at the proportion of 3/2 as solvents was conducted. The influence of extraction temperature (35, 45, and 55°C), ultrasound treatment time (30, 60, and 90 min), and solvent-to-canola (sample) ratio (5, 10, and 15 (% v/w)) on the percentage of the extracted oil and oxidative stability of the extracted oil was analyzed through Box-Behnken design. The achieved results revealed that the optimized conditions for canola oil extraction (22.39% efficiency) by hexane was 87 min ultrasound treatment at 55°C and solvent-to-canola proportion of 6.39 (% v/w). On the other hand, the optimized conditions for canola oil extraction (30.66% efficiency) by hexane–isopropanol mixture were 69.5 min ultrasound treatment at 55°C and solvent-to-canola ratio of 9.12 (% v/w). The obtained outcomes revealed that ultrasound waves significantly improved the extraction efficiency compared to Soxhlet extraction. The extraction efficiency was improved when hexane–isopropanol mixture was applied. In optimized condition, oxidative stability of the extracted oil has been achieved at 12.55 and 40.9 h, respectively, once hexane and hexane–isopropanol were used as solvents for extraction. Oxidative stability presented considerable enhancement with an increase in ultrasound treatment. Extracted oil with the use of mixed solvent (hexane–isopropanol) presented higher value for oxidative stability compared to the extracted oil with the use of hexane as a solvent. Comparison between the ultrasound-assisted and Soxhlet extracted oils with the use of gas chromatography presented no significant difference in their fatty acid profiles.

Stability of Omega-3 LC-PUFA-rich Photoautotrophic Microalgal Oils Compared to Commercially Available Omega-3 LC-PUFA Oils

Microalgae are the primary producers of omega-3 LC-PUFA, which are known for their health benefits. Their oil may thus be a potential alternative for fish oil. However, oxidative and hydrolytic stability of omega-3 LC-PUFA oils are important parameters. The purpose of this work was therefore to evaluate these parameters in oils from photoautotrophic microalgae (Isochrysis, Phaeodactylum, Nannochloropsis gaditana, and Nannochloropsis sp.) obtained with hexane/isopropanol (HI) and hexane (H) and compare them with commercial omega-3 LC-PUFA oils. When the results of both the primary and secondary oxidation parameters were put together, it was clear that fish, tuna, and heterotrophic microalgae oil are the least oxidatively stable oils, whereas krill oil and the microalgae oils performed better. The microalgal HI oils were shown to be more oxidatively stable than the microalgal H oils. The hydrolytic stability was shown not to be a problem during the storage of any of the oils.

Comparison of Eleven Extraction Methods for Quantitative Evaluation of Total Lipids and Fatty Acids in the ClamAnadara inaequivalvis(Bruguière)

The clam Anadara inaequivalvis (Bruguière) is a bivalve mollusc now populating several areas of the Mediterranean Sea seafloor where it competes with other molluscs harvested as food. In fact, even though Anadara inaequivalvis has valuable nutritional properties, it has no commercial value in European countries. The aim of this study was to evaluate quantitatively and qualitatively fatty acid content in this bivalve mollusc and to compare 11 extraction methods: conventional procedures such as Folch, Bligh and Dyer, and Soxhlet with different solvents, as well as accelerated solvent extraction (ASE) and methods using low-toxicity solvents as substitutes for chloroform (CHCl3) and methanol (MeOH). The best method was ASE CHCl3-MeOH, affording yields of total lipids, total fatty acids, and polyunsaturated fatty acids (PUFAs) significantly higher than any other method. The estimated range of total lipids was 2.29%–6.99% (on the dry sample), and the range of fatty acids was 0.74%–1.78%. Yields of polyunsaturated fatty acids (PUFAs) ranged from 0.10% to 0.40%. The solvent mixture hexane—isopropanol as substitute for CHCl3-MeOH did not afford good results. PUFAs were 22.5% in the total fatty acids and the ratio between PUFAs n-3 and PUFA n-6 was 2.74:1.

Characterization of the Lipid Fraction in Lamb Meat: Comparison of Different Lipid Extraction Methods

The aim of this study was to evaluate the performance of four different extraction methods commonly used to quantify the intramuscular lipid content in meat: the Association of Analytical Chemists (AOAC) method (reference method) and methods based on the use of a solvent mixture with different polarities, such as chloroform–methanol described by Folch et al. (J Biol Chem 226:497, 1957) and Christie (1989) or hexane–isopropanol described by Hara and Radin (Anal Biochem 90:420, 1978). The following parameters were taken into account: lipid content; relative proportions of neutral and polar lipids; fatty acid composition of total, neutral, and polar lipid fractions; and phospholipid composition. The use of a combination of solvents with different polarities (Hara–Radin, Folch, and modified Folch methods) was more effective in extracting intramuscular lipids than the use of a single solvent (AOAC, reference method). The Hara–Radin method provided a cleaner lipid extract with a significantly higher content of total fatty acids than that obtained with the Folch and modified Folch methods. The lower polarity of the hexane–isopropanol mixture allowed us to obtain an extract richer in neutral lipids (triglycerides and diglycerides) and thus in saturated and monounsaturated fatty acids. The percentage distribution of individual fatty acids in the neutral lipid fraction was generally not affected by the extraction method adopted, while lipid obtained with both the Hara–Radin and Folch methods had a polar fraction with a higher percentage of polyunsaturated fatty acids. The use of the Hara–Radin method provided a polar fraction with less nonlipid material and lower phospholipid degradation.

Isolation and purification of heroin from heroin street samples by preparative high performance liquid chromatography

The present study established a novel method using preparative high performance liquid chromatography to isolate and purify heroin·HCl from heroin street samples to be used as a reference standard. Different kinds of mobile phases and columns were used, ultimately the mobile phase consisting of hexane-isopropanol-methanol (65:28:7, v/v) and the SIL preparative column prepared in laboratory were selected as the final condition. Heroin was further purified by the drowning-out crystallization method using isopropanol-methanol (50:1, v/v) and hexane as drowning-out anti-solvents and salting-out agents, respectively. The purity was assessed by analytical high performance liquid chromatography and the confirmation of the chemical structure was performed by IR and NMR. About 110.7mg of heroin·HCl at a purity of over 99.52% was obtained from 180mg of heroin street samples which contained 156.15mg of heroin·HCl component by preparative high performance liquid chromatography. This method is suitable for preparing heroin standards in forensic science area.

Quantification of Rimonabant (SR 141716A) in Monkey Plasma Using HPLC with UV Detection

Using an isocratic high-performance liquid chromatography (HPLC) system and UV detection, a simple and precise analytical procedure was developed to quantify levels of the CB(1) receptor antagonist rimonabant in the plasma of rhesus monkeys. Rimonabant was extracted from plasma samples into 5% isopropanol in hexane. After separation, the isopropanol-hexane fractions were dried to residue, redissolved in mobile phase, and then injected into the HPLC. The HPLC system included an acetonitrile-phosphate buffer (62:38, v/v) mobile phase (pH 6.7), flow rate of 1.5 mL/min, C(18) column (4.6 mm i.d. x 150 mm length, 5 microm), and UV detection at 280 nm. Retention times for rimonabant and doxepin (internal standard) were 9.9 and 2.4 min, respectively. The regression of the spiked calibrator curve was linear from 60 to 4000 ng/mL (r(2) = 0.996). The lower limit of quantification was 60 ng/mL, and recovery was 83.6%. Rimonabant was stable in stock solutions and monkey plasma across a range of temperatures and concentrations. To demonstrate utility, plasma rimonabant was measured in six rhesus monkeys at 60 and 240 min after intramuscular administration of 1 mg/kg rimonabant. Rimonabant levels ranged from 175 to 1290 ng/mL. The analytical assay described here provides a simple and accurate procedure for multiple within-subject measurements of the CB(1) antagonist rimonabant.

Western diet changes cardiac acyl-CoA composition in obese rats: a potential role for hepatic lipogenesis

The "lipotoxic footprint" of cardiac maladaptation in diet-induced obesity is poorly defined. We investigated how manipulation of dietary lipid and carbohydrate influenced potential lipotoxic species in the failing heart. In Wistar rats, contractile dysfunction develops at 48 weeks on a high-fat/high-carbohydrate "Western" diet, but not on low-fat/high-carbohydrate or high-fat diets. Cardiac content of the lipotoxic candidates--diacylglycerol, ceramide, lipid peroxide, and long-chain acyl-CoA species--was measured at different time points by high-performance liquid chromatography and biochemical assays, as was lipogenic capacity in the heart and liver by qRT-PCR and radiometric assays. Changes in membranes fluidity were also monitored using fluorescence polarization. We report that Western feeding induced a 40% decrease in myocardial palmitoleoyl-CoA content and a similar decrease in the unsaturated-to-saturated fatty acid ratio. These changes were associated with impaired cardiac mitochondrial membrane fluidity. At the same time, hepatic lipogenic capacity was increased in animals fed Western diet (+270% fatty acid elongase activity compared with high-fat diet), while fatty acid desaturase activity decreased over time. Our findings suggest that dysregulation of lipogenesis is a significant component of heart failure in diet-induced obesity.

Two methods for the separation of monounsaturated octadecenoic acid isomers

The identification and quantification of complex mixtures of cis and trans octadecenoic (18:1) fatty acid isomers presents a major challenge for conventional one-dimensional GC/FID analysis of their methyl esters. We have compared the use of two methods to achieve optimized separations of positional and geometrical octadecenoic fatty acid isomers—comprehensive two-dimensional gas chromatography (GC × GC), and silver ion high performance liquid chromatography interfaced to atmospheric pressure photoionization (APPI) mass spectrometry. Nine isomers of octadecenoic acid methyl ester were well separated on a single silver ion column with a mobile phase of 0.018% acetonitrile and 0.18% isopropanol in hexane. Reproducible retention times were obtained with relative standard deviations of around 1% over 5 injections. The extra selectivity and reproducibility afforded by APPI-MS, together with the wide separation of cis and trans isomers by silver ion chromatography, resulted in a promising method for measurement of octadecenoic acid FAME. The GC × GC separation was performed using various column combinations, and optimal separation was obtained by coupling an ionic liquid column (Supelco SLB-IL100 [1,9-di(3-vinyl-imidazolium) nonane bis(trifluoromethyl) sulfonyl imidate]) in the first dimension with a SGE BPX50 (50% phenyl polysilphenylene-siloxane) in the second dimension. These methods have been applied to the analysis of octadecenoic acid in milk and beef fat.

Improved extraction of oil from chickpea under ultrasound in a dynamic system

Abstract In this work, ultrasound-assisted dynamic extraction (UADE) is proposed. The dynamic approach allows go-and-backward circulation of solvent through the sample subjected to the action of ultrasound. The extraction efficiency of hexane, isopropanol, a hexane–isopropanol mixture as well as the comparison between static extraction and flow-through extraction with or without ultrasound were evaluated. The effects of ultrasonic power, extraction temperature, time and extractant flow rate on the yield of oil from chickpea were also investigated. Results showed that solvent type significantly influenced extraction efficiency, the combination of hexane and isopropanol obtained the highest oil yield. Dynamic system and ultrasonication dramatically enhanced the extraction of oil. Moreover, results indicated that 20 min was sufficient for UADE with lower cost to obtain higher extraction yields (10.45% and 2.06% higher) than those by 4 h conventional solvent extraction (CSE) and 30 min ultrasound-assisted extraction (UAE) for oil. Gas chromatography analysis of chickpea oil indicated that the oil was enriched with polyunsaturated fatty acids and few changes in fatty acid composition occurred in ultrasonicated oil.

Enantioselective analysis of praziquantel and trans-4-hydroxypraziquantel in human plasma by chiral LC–MS/MS: Application to pharmacokinetics

A simple enantioselective method for the determination of praziquantel (PZQ) and trans-4-hydroxypraziquantel (4-OHPZQ) in human plasma was developed and validated by high-performance liquid chromatography/mass spectrometry. The plasma samples were prepared by liquid–liquid extraction using a mixture of methyl-tert-butylether/dichloromethane (2:1, v/v) as extraction solvent. The direct resolution of PZQ and 4-OHPZQ enantiomers was performed on a Chiralpak AD column using hexane–isopropanol (75:25, v/v) as the mobile phase. Diazepam was used as internal standard. The method described here is simple and reproducible. The quantitation limit of 1.25 ng/ml for each PZQ enantiomer and of 12.5 ng/ml for each 4-OHPZQ enantiomer permits the use of the method in studies investigating the kinetic disposition of a single dose of 1.5 g racemic PZQ. Enantioselectivity in the kinetic disposition of PZQ and 4-OHPZQ was observed in the clinical study, with the demonstration of a higher proportion of the (+)-(S)-PZQ and (−)-(R)-4-OHPZQ enantiomers in plasma.

Comparative studies on the yield and quality of solvent-extracted oil from salmon skin

Oil was extracted from the skin of Atlantic salmon by solvent extraction with different solvent systems and analyzed for efficiency in terms of oil yield and quality. The yield of salmon skin oil (SSO) was significantly lower ( p < 0.05) with the hexane–isopropanol solvent system versus either of the chloroform-methanol systems, i.e., 32.21% on dry weight basis (dwb) against 35.15% dwb and 43.82% dwb, respectively. Second and third extractions were performed on the residue using the same solvent systems to verify any biases and to test the completeness of the first extraction. These successive extractions resulted in nominal increases in yield. The yield of SSO from Soxhlet-hexane compared favorably with Soxhlet-petroleum ether at all the extraction times investigated. The Soxtec-hexane gave the highest oil yield of ca 62% dwb. Both hexane and petroleum ether were suitable solvents for the extraction of SSO, though the yield obtained with hexane was significant higher ( p < 0.05). The study further indicated that salmon skin was a rich source of oil (23.32–61.53% dwb) and for the various solvent systems, the free fatty acid (FFA) content was quite low (0.60–1.19%).

HPLC separation of some purine and pyrimidine derivatives on Chromolith Performance Si monolithic column

The chromatographic behavior of some purines and pyrimidines on a monolithic Chromolith Performance Si column under normal-phase high-performance liquid chromatography mode has been studied. Column pressure, column efficiency and selectivity of Chromolith Performance Si column were compared to those of conventional spherical 5 μm silica packed columns Econosphere Silica and Zorbax Rx-SIL. The investigation has shown that application of Chromolith Performance Si column for analysis of polar solutes can reduce the separation time without sacrificing column efficiency and selectivity. Improvement of the monolithic silica column efficiency for polar solutes is observed when ternary mobile phases (mixtures of hexane–isopropanol with ethylene glycol, water or acetonitrile) are applied.

Structure–enantioselectivity relationship of hypnotic-sedative 1,4-disubstituted piperazine derivatives on cellulose tris(4-methylbenzoate) chiral stationary phase

Chromatographic behaviour of 19 chiral 1,4-disubstituted piperazine derivatives with hypnotic-sedative activity has been examined on cellulose tris(4-methylbenzoate) with hexane–isopropanol mobile phases. The chiral resolution has been obtained for of 14 (out of 19) compounds. While three of the resolved compounds ( 5, 6 and 10) did not undergo enantiodifferentiation ( α = 1) at relatively high isopropanol content (50–10%) in hexane, however, enantiodifferentiation was possible ( α = 1.06–1.40) at lower isopropanol contents. Enantioselectivity changes induced by isopropanol content variations were discussed in terms of the concept of true and apparent separation factors. The retention factors of the compounds were described with the aid of modified Soczewiński–Snyder equation. Theoretical calculations were carried out for the chiral stationary phase model, which stressed the importance of a solute and the stationary phase aromatic ring interactions.

Assessment of thein-vivo stereochemical integrity of aprepitant based on the analysis of human plasma samples via high-performance liquid chromatography with mass spectrometric detection

Achiral and chiral liquid chromatographic methods utilizing mass spectrometric detection were developed to investigate the possibility of inversion of configuration at any or all of the chiral centers of the neurokinin-1 (NK-1) receptor antagonist, aprepitant (5-[[2(R)-[1(R)-(3,5-bistrifluoromethyl phenyl)ethoxy]-3(S)-(4-fluorophenyl)morpholin-4-yl]methyl]-2,4-dihydro-[1,2,4]triazol-3-one), in-vivo, following administration of the compound to man. A structure such as aprepitant, that contains three chiral centers, may exist in eight stereochemical forms or, more specifically, as four diastereoisomeric pairs of enantiomers. The four diastereoisomers were separated from each other using a ProntoSil C18 AQ HPLC column (4.6 x 100 mm, 3 microm particles) with a mobile phase composed of acetonitrile--water (47:53, v/v%). Detection was via a single quadrupole mass spectrometer that was connected to the HPLC system via an APCI interface. Analysis of post-dose plasma samples under these conditions indicated that only aprepitant and or its enantiomer were present following oral administration of the drug. Aprepitant and its enantiomer were separated using a Chiralcel OD-H HPLC column with a mobile phase composed of hexane-isopropanol (80:20, v/v%); tandem mass spectrometric detection using an APCI interface was employed. Post-dose plasma samples analyzed using the Chiracel column were found to contain only aprepitant. The results of these experiments confirm that the products of inversion of configuration at any or all of the three chiral centers of aprepitant are not detectable in human plasma samples obtained following the administration of the drug.

Identification of glycerophospholipids in rapeseed, olive, almond, and sunflower oils by LC–MS and LC–MS–MS

HPLC employing a thermostatted Lichrospher 100 diol column was used to separate mixtures of glycerophospholipids of rapeseed, olive, almond, and sunflower oils. Elution was performed with a binary gradient of two mixed solvents A: hexane – isopropanol – acetic acid – triethylamine (82:17:1.0:0.08 v/v/v/v) and B: isopropanol – water – acetic acid – triethylamine (85:14:1.0:0.08 v/v/v/v). The LC effluent was directly introduced into the mass spectrometer through an electrospray capillary. Information about the fatty acid composition of each glycerophos pho lipid class was given by tandem mass spectrometry (MS–MS). These techniques permitted a rapid separation and identification of complex mixtures of glycerophospholipids. The relative abundance of each lipid class in each oil was also determined. The resulting glycerophospholipid signature may provide an efficient means of identifying oil origin and possible adulteration.Key words: glycerophospholipids, vegetable oils, tandem mass spectrometry, LC–MS.