Determination of the fatty acid composition of saponified vegetable oils using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

A method using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) for the determination of the fatty acid composition of vegetable oils is described and illustrated with the analysis of palm kernel oil, palm oil, olive oil, canola oil, soybean oil, vernonia oil, and castor oil. Solutions of the saponified oils, mixed with the matrix, meso-tetrakis(pentafluorophenyl)porphyrin, provided reproducible MALDI-TOF spectra in which the ions were dominated by sodiated sodium carboxylates [RCOONa + Na]+. Thus, palm kernel oil was found to contain capric acid, lauric acid, myristic acid, palmitic acid, oleic acid, and stearic acid. Palm oil had a fatty acid profile including palmitic, linoleic, oleic, and stearic. The relative percentages of the fatty acids in olive oil were palmitoleic (1.2 +/- 0.5), palmitic (10.9 +/- 0.8), linoleic (0.6 +/- 0.1), linoleic (16.5 +/- 0.8), and oleic (70.5 +/- 1.2). For soybean oil, the relative percentages were: palmitoleic (0.4 +/- 0.4), palmitic (6.0 +/- 1.3), linolenic (14.5 +/- 1.8), linoleic (50.1 +/- 4.0), oleic (26.1 +/- 1.2), and stearic (2.2 +/- 0.7). This method was also applied to the analysis of two commercial soap formulations. The first soap gave a fatty acid profile that included: lauric (19.4% +/- 0.8), myristic (9.6% +/- 0.5), palmitoleic (1.9% +/- 0.3), palmitic (16.3% +/- 0.9), linoleic (5.6% +/- 0.4), oleic (37.1% +/- 0.8), and stearic (10.1% +/- 0.7) and that of the second soap was: lauric (9.3% +/- 0.3), myristic (3.8% +/- 0.5), palmitoleic (3.1% +/- 0.8), palmitic (19.4% +/- 0.8), linoleic (4.9% +/- 0.7), oleic (49.5% +/- 1.1), and stearic (10.0% +/- 0.9). The MALDI-TOFMS method described in this communication is simpler and less time-consuming than the established transesterification method that is coupled with analysis by gas chromatography/mass spectrometry (GC/MS). The new method could be used routinely to determine the qualitative fatty acid composition of vegetable oils, and, when fully validated by comparison with standard analytical methodologies, should provide a relatively fast quantitative measurement of fatty acid mixtures and/or soap formulations that contain saturated and unsaturated hydrocarbon moieties.     

Simultaneous analysis of glycolipids and phospholids molecular species in avocado (Persea americana Mill) fruit

The molecular species of phospholipids (PLs) and glycolipids (GLs) were simultaneously characterized in the pulp and almond of the avocado fruit (Persea americana Mill) of four varieties by means of high performance liquid chromatography-electrospray ionisation ion-trap tandem mass spectrometry. In the pulp, the predominant species of monoglycosyldiglycerides (MGD) were m/z 796.6 (oleic/linolenic and linoleic/linoleic acids) and m/z 800.4 (stearic/linoleic and oleic/oleic acids). One of the main diglycosyldiglycerides (DGD) both in the pulp and almond was m/z 958.5 (oleic/linolenic); however, the pulp was also rich of m/z 962.4 (oleic/oleic), whereas in the almond, m/z 934.5 (palmitic/linoleic and palmitoleic/oleic) and m/z 960.5 (oleic/linoleic and stearic/linolenic) were more abundant. In the almond, the main PL classes (phosphatidic acid (PA), phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylinositol (PI)) contained always palmitic/linoleic acids. Alpha-linolenic acid was contained as MGD (linolenic/linolenic) and DGD (linolenic/linolenic), more present in the pulp than in the almond. The major molecular species of glycocerebrosides (GCer) in the pulp and almond carried hydroxy-palmitic acid (C(16h:0))/4,8-sphyngadienine (d(18:2)).     

杏仁油的物化性能及其脂肪酸组成的分析

用３种不同溶剂萃取杏仁得到杏仁油,并对其物化常数进行测定。杏仁油用饱和氢氧化钾 甲醇皂化,再用甲醇 硫酸（体积比为４∶１）甲酯化后,将乙醚萃取液作气相色谱分析。太原杏仁油中脂肪酸的主要成分为油酸（Ｃ１８∶１,质量分数约６８％）和亚油酸（Ｃ１８∶２,质量分数约２５％）,少量棕榈酸（Ｃ１６∶０）、棕榈烯酸（Ｃ１６∶１）和硬脂酸（Ｃ１８∶０）,微量花生酸（Ｃ２０∶０）。     

Fatty acid composition and chemotaxonomic evaluation of species of Stachys

The fatty acid composition of the seed oil of 23 Stachys taxa was analysed by GC/MS. The main compounds were found to be linoleic (27.1-64.3%), oleic (20.25-48.1%), palmitic (4.3-9.1%), stearic (trace to 5.2%) and 6-octadecynoic (2.2-34.1%) acids. The latter compound could be used as a chemotaxonomic marker of the genus Stachys. A cluster analysis was performed for comparison and characterisation of the seed oil from Stachys species.     

海棠果种子油脂肪酸成分研究

用乙醚萃取海棠果种子油,油脂皂化后的脂肪酸采用三氟化硼-甲醇溶液进行甲酯化.采用气相色谱-质谱-计算机联用技术分离、鉴定出7种主要脂肪酸,进一步采用气相色谱法定量测定脂肪酸,分别为肉豆蔻酸0.02%,软脂酸8.64%,硬脂酸8.96%,油酸37.7%,亚油酸20.1%,亚麻酸0.38%,二十碳酸0.85%.结果表明,海棠果种子油不饱和脂肪酸质量分数高达58%,值得作为不饱和脂肪酸食用油来源开发.     

High performance liquid chromatography determination of fatty acids in drying oils following lipase action

This paper describes a quantitative analytical procedure to determine the fatty acid composition in drying oils like linseed, walnut and poppy seed. The procedure required the enzymatic hydrolysis of the oil triacylglycerol families by the action of Candida rugosa lipase. The fatty acids (FFAs) produced (linolenic, myristic, linoleic, palmitic, oleic and stearic) were extracted with n-heptane and derivatized with α-bromoacetophenone. Their separation and quantitative determination were performed by high-performance liquid chromatography employing a C18 column and an isocratic elution method coupled to ultraviolet detection. The analytical enzymatic procedure is sensitive for < 0.5 μg/mL of FFAs in a reduced sample of 0.1 mg of drying oil.     

Fatty acid composition of seeds of some species of Nepeta L

The fatty acid compositions of Nepeta viscida, N. cilicica, N. crinita, N. nuda ssp. glandulifera and N. aristata were analyzed by GC/MS. The main free fatty acids were found as linolenic acid (49.8-58.5%), linoleic acid (10.9-23.5%), oleic acid (11.5-19.2%), palmitic acid (5.2-6.8%) and stearic acid (2.0-3.7%) and, total fatty acid compositions of species were analyzed and results were found as 36.2-49.8%, 17.1-25.8%, 15.4-25.8%, 6.4-7.8%, and 2.7-4.1%, respectively.     

Fatty acid composition of two Athamanta turbith subspecies

The fruit oils of Athamanta turbith ssp. hungarica and Athamanta turbith ssp. haynaldii were obtained by Soxhlet extraction using petroleum ether. The fatty acid composition of oils was determined by GC in the methyl ester form. Considering the composition and content of fatty acids, the examined oils were very similar. Petroselinic acid was the principal one (45.6 and 46.2%, respectively), followed by a significant amount of linoleic acid (26.9 and 29.1%, respectively). In both oils, myristic, pentadecanoic, palmitic, palmitoleic, stearic, petroselinic, oleic, linoleic, α-linolenic, arachidic, and behenic acid were identified. Lignoceric acid was detected only in A. turbith ssp. hungarica oil. Published in Khimiya Prirodnykh Soedinenii, No. 4, pp. 319–320, July–August, 2006.     

Gas-chromatographic fatty-acid fingerprints and partial least squares modeling as a basis for the simultaneous determination of edible oil mixtures

Partial least squares modeling and gas-chromatographic fatty-acid fingerprints are reported as a method for the simultaneous determination of cottonseed, olive, soybean and sunflower edible oil mixtures. In this work, two sets of three- and four-component combinations of oils were prepared, hydrolyzed and the obtained free fatty acids analyzed by gas chromatography (GC) without any further derivatization. The normalized percentages of the myristic (14:0), palmitic (16:0), palmitoleic (16:1), stearic (18:0), oleic (18:1), linoleic (18:2) and linolenic (18:3) acids were chromatographically measured in samples and used for constructing calibration matrix. The cross-validation method was used to select the number of factors and the proposed methods were validated by using two sets of synthetic oil mixture samples. The relative standard error for each oil in mixture samples was less than 10%. This approach allows determining possible adulteration in each of the four edible oils.     

在线热辅助甲基化-气相色谱法分析棉籽仁中的脂肪酸组成

建立了分析棉籽仁中脂肪酸组成的在线热辅助甲基化-气相色谱法。将0.3 mg棉籽仁样品与2 μ L三甲基氢氧化硫（0.2 mol/L）加入裂解器,在350℃下进行甲基化反应,通过气相色谱仪进行分离分析,共检测到8种脂肪酸甲酯成分,分别为亚油酸（C18：2）、油酸（C18：1）、棕榈酸（C16：0）、硬脂酸（C18：0）、肉豆蔻酸（C14：0）、棕榈油酸（C16：1）、花生酸（C20：0）和二十二酸（C22：0）,不饱和脂肪酸的相对含量为66.30%~72.54%,其中亚油酸的相对含量为43.20%~53.61%,相对峰面积的相对标准偏差（RSD）小于10%（n=5）。通过分析5组棉籽仁样品与3种食用油中的脂肪酸组成,结果表明不同产地的棉籽仁中的脂肪酸组成差异不明显,且棉籽仁中的脂肪酸组成与玉米油最为接近,相似度为0.960~0.992。该方法简单、快速、准确,适合分析棉籽仁中的脂肪酸组成。     

GC／MS法分析鳗鱼骨油的脂肪酸

用乙醚／已烷混合溶剂抽提鳗鱼骨油，用ＫＯＨ－ＣＨ_３ＯＨ酯交换法甲酯化，以毛细管色谱／质谱方法测定脂肪酸的组成。共检出２７种脂肪酸，其中以棕榈油酸、棕榈酸、油酸、硬脂酸、花生烯酸为主。     

Characterization of copolymer hydroxybutyrate/hydroxyvalerate from saponified vernonia,soybean, and "spent" frying oils

Poly(beta-hydroxyalkanoate)s (PHAs) were biosynthesized by Ralstonia eutropha (formerly known as Alcaligenes eutrophus) by using saponified soybean, vernonia, and "spent" frying oils. These PHAs were isolated and characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS), gas chromatography/mass spectrometry (GC/MS), proton nuclear magnetic resonance spectrometry (1H NMR), and 2-dimensional homonuclear (1H-1H) correlation spectroscopy (COSY). The analytical results revealed that the PHAs produced from saponified vernonia and soybean oils were copolymers of hydroxybutyrate (HB) and hydroxyvalerate (HV), that is, P(HB/HV)s, whereas the saponified "spent" frying oil produced only poly(beta- hydroxybutyrate) (PHB) homopolymer. MALDI-MS, GC/MS, and NMR independently confirmed the composition of the PHAs. Saponified soybean oil and vernonia oil PHAs contained approximately 4 and 1% HV units, respectively. For comparison, commercial PHB and P(HB/HV), produced by R. eutropha by using glucose and a cosubstrate of glucose and propionic acid, respectively, as carbon sources, were similarly characterized.     

6-Oxy-(acetyl ethylenediamine) fluorescein, a novel fluorescent derivatization reagent for carboxylic acids and its application in HPLC

A novel fluorescent derivatization reagent for carboxylic acids, 6-oxy-(acetyl ethylenediamine) fluorescein (AEF), was well designed, synthesized, and applied to HPLC. The derivatization reaction with 12 fatty acids, including n-valeric acid (C5), n-hexanoic acid (C6), n-heptanoic acid (C7), n-octanoic acid (C8), n-nonanoic acid (C9), n-decanoic acid (C10), lauric acid (C12), myristic acid (C14), palmitic acid (C16), stearic acid (C18), oleic acid (C18:1), and linoleic acid (C18:2), was completed at 55 degrees C within 40 min. The derivatives of fatty acids were separated on a C18 RP column and detected by fluorescence detection. The LODs attained were 0.4-1.2 nM (S/N of 3). It has been demonstrated that AEF is a prominent derivatization reagent for carboxylic acids which is suitable for HPLC.     

Compositions of the seed oil of the Borago officinalis from Iran

In order to investigate the composition of borage (Borago officinalis L.) seed oil, this research was performed under the field conditions at Shahriyar and Garmsar zones, Iran during the 2012 planting year. The oil yield of borage was 31.46% and 33.7% at Shahriyar and Garmsar zone, respectively, and nine and eight fatty acids were identified in the seed oil of borage at Shahriyar and Garmsar, respectively – palmitic, linoleic, stearic and γ-linolenic acids were dominant in the seed oil of borage from both zones. Unsaturated fatty acid content was more than the saturated fatty acids in both zones. The ratio of linoleic acid and α-linolenic acid in the borage cultivated at Shahriyar and Garmsar zones was 2.13 and 2.29. The fatty acid profile of Garmsar borage, oleic and oleic/linoleic acid ratio, increased. Locations with different ecological conditions resulted in changes in both seed oil content and fatty acid profile of borage.     

Fatty acid content of three <Emphasis Type="Italic">Cistus</Emphasis> species growing in Turkey

The seed oils of Cistus laurifolius, C. salviifolius, and C. creticus were investigated for their fatty acids by employing capillary GC and capillary GC-MS. The results of this study indicated that palmitic, linoleic, linolenic, oleic, stearic, and behenic acids were found in all of these three seed oils of Turkish origin. In addition, an important polyunsaturated fatty acid, linoleic acid, was the major fatty acid in all of these oil samples.Published in Khimiya Prirodnikh Soedinenii in No. 6, pp. 433–434, November–December.This revised version was published online in April 2005 with a corrected cover date.     

白果中脂肪酸的GC-MS分析

将萃取所得白果油进行皂化、甲酯化后 ,进行GC-MS定性及相对含量分析 ,取得了满意的结果。实验检出30种脂肪酸 ,其中亚油酸和油酸占71.8%,不饱和脂肪酸占87.86%。     

Hollow fiber liquid-phase microextraction coupled with gas chromatography-flame ionization detection for the profiling of fatty acids in vegetable oils

The development of a two phase hollow fiber liquid-phase microextraction technique, followed by gas-chromatography-flame ionization detection (GC-FID) for the profiling of the fatty acids (FAs) (lauric, myristic, palmitic, stearic, palmitoleic, oleic, linoleic, linolenic and arachidic) in vegetable oils is described. Heptadecanoic acid methyl ester was used as the internal standard. The FAs were transesterified to their corresponding methyl esters prior to the extraction. Extraction parameters such as type of extracting solvent, temperature, extraction time, stirring speed and salt addition were studied and optimized. Recommended conditions were extraction solvent, n-tridecane; extraction time, 35 min; extraction temperature, ambient; without addition of salt. Enrichment factors varying from 37 to 115 were achieved. Calibration curves for the nine FAs were well correlated (r(2)>0.994) within the range of 10-5000 μg L(-1). The limit of detection (signal:noise, 3) was 4.73-13.21 ng L(-1). The method was successfully applied to the profiling of the FAs in palm oils (crude, olein, kernel, and carotino cooking oil) and other vegetable oils (soybean, olive, coconut, rice bran and pumpkin). The encouraging enrichments achieved offer an interesting option for the profiling of the minor and major FAs in palm and other vegetable oils.     

甲鱼油脂肪酸组成的研究

用热提取方法抽取出甲鱼油，用ＫＯＨ－ＣＨ３ＯＨ酯交换法甲酯化处理，以色谱／质谱方法测定脂肪酸的组成。共鉴定出２１种脂肪酸，其中以棕榈酸、棕榈油酸、硬脂酸、油酸、亚油酸、二十碳五烯酸（ＥＰＡ）、二十二碳五烯酸（ＤＨＡ）为主     

Evaluation of chemical constitute,fatty acids and antioxidant activity of the fruit and seed of sea buckthorn (Hippophae rhamnoides L.) grown wild in Iran

In this investigation, the chemical compositions of berries from sea buckthorn were studied. The amount of ascorbic acid and β-carotene determined by HPLC was 170 mg/100 g FW and 0.20 mg/g FW, respectively. Total phenols, anthocyanins, acidity and total soluble solids (TSS) contents were 247 mg GAE/100 g FW, 3 mg/L (cyanidin-3-glucoside), 5.32% and 13.8%, respectively. Fruit antioxidant activity determined by the ferric reducing ability of plasma (FRAP) method was 24.85 mM Fe/100 g FW. Results confirmed the presence of six dominant fatty acids (determined by GC) in fruit including linoleic (34.2%), palmitoleic (21.37%), palmitic (17.2%), oleic (12.8%), linolenic (5.37%) and stearic acid (1.67%). Five dominant fatty acids of the seeds were linoleic (42.36%), linolenic (21.27%), oleic (21.34%), palmitic (6.54%) and stearic acid (2.54%). The nitrogen content was 3.96%. The P, K, Ca, Mg, Fe, Zn, Mn, Cu, Cd and Cl contents of fruit were 491, 1674, 1290, 990, 291, 29.77, 108.37, 17.87, 0.021 and 2.18 mg/kg DW, respectively.     

6-oxy-(acetyl piperazine) fluorescein as a new fluorescent labeling reagent for free fatty acids in serum using high-performance liquid chromatography

A new fluorescein-based fluorescent derivatizating reagent, 6-oxy-(acetyl piperazine) fluorescein (APF), has been designed, synthesized and developed for carboxylic acid labeling. It was used as a pre-column derivatizing reagent for the determination of seven free fatty acids (lauric acid, myristic acid, arachidonic acid, linoleic acid, palmitic acid, oleic acid, and stearic acid) with high-performance liquid chromatography (HPLC). The derivatization reaction of APF with seven fatty acids was completed at 60 degrees C for 1 h using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) as the condensing reagent. On a C18 column, the derivatives of APF with seven free fatty acids could be separated completely in 22 min using a mobile phase of methanol-water (88:12, v/v) containing 7 mmol L(-1) pH 6.5 Na2HPO4-H3Cit3 buffer with fluorescence detection at lambdaex/lambdaem=467/512 nm. The detection limits could reach 0.1-6.4 nmol L(-1) (signal-to-noise=3). This reagent was applied to the determination of the free fatty acids in human serum samples with satisfying recovery efficiencies varying from 93 to 105%.