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1.
A simple and reliable high-performance liquid chromatography method for the analysis of diesel oil in contaminated edible
oils is described. Analysis performed using a diol column with a mobile phase of heptane and isopropanol (94∶6, vol/vol).
Although baseline separation between diesel and other background fluorescent components was not achieved, quantitation was
still possible using baseline integration. The method is linear over the range of 5–1000 μg/g with a correlation coefficient
(r
2) of 0.9984. Average recoveries from spiked edible oils were 94.4–101.3%, with a limit of quantitation (LOQ) of 5 μg/g for
sunflower oil, palm olein, and groundnut oil. Corn oil has a higher content of ester components, thus, LOQ was slightly worse
(40 μg/g). The applicability of the method was confirmed by gas chromatography-mass spectroscopic detection to show the presence
of diesel hydrocarbons in the suspected contaminated crude palm oil. This procedure provides a simple and sensitive method
for determining diesel oil concentration in contaminated edible oils without prior sample cleanup or extraction. 相似文献
2.
Concentrations of synthetic antioxidants butylated hydroxyanisole, butylated hydroxytoluene, and tert-butyl hydroquinone were quantified using a high-performance liquid chromatograph with spectrofluorometric detector. The antioxidants
were separated and eluted on a reversed-phase column by gradient of a mixture of H2O/acetonitrile/acetic acid (66.5: 28.5∶5, by vol) and a mixture of acetonitrile/acetic acid (95∶5, vol/vol). The eluants were
monitored at emission and excitation wavelengths of 310 and 280 nm, respectively. Calibration curves obtained using peak areas
against concentration showed ligh coefficients of multiple determination (R
2>0.99) for all antioxidants. Known concentrations of added antioxidant standards were recoverable within 98–99% from oils
and over 93% from mouse blood. This method requires minimum sample extraction and purification before analysis and provides
a relatively high percentage recovery. The method has been applied successfully for the measurement of antioxidant concentrations
in oils, dried foods, and biological fluids. 相似文献
3.
An HPLC method for the determination of partially hydrogenated terphenyls-based thermal heating fluid, Therminol 66™, in various vegetable oils is described. Direct analysis of palm olein showed that the 3- and 4-cyclohexylbiphenyl peaks
of the Therminol 66™ used in quantitative analysis co-eluted with other fluorescent peaks present naturally in the oil. However, those interfering
peaks were readily removed after saponification of palm olein. The concentrations of the 3- and 4-cyclohexylbiphenyls of Therminol
66™ were monitored by fluorescence detection at 257 (excitation) and 320 nm (emission). The calibration graph obtained by using
the peak areas of the 3- and 4-cyclohexylbiphenyls against the concentrations of Therminol 66™ was linear, with a correlation coefficient of 0.994. The limit of quantitation, using spiked palm olein, was as low as 0.2
μg/g. The coefficients of variation obtained from the intra- and interday studies obtained by using three spiked concentrations
(0.2, 0.5, and 1.0 μg/g) were 1.76–6.43 and 3.77–10.4%, respectively. The mean recovery value obtained from sunflower, soybean,
and canola oils was more than 88.7%. 相似文献
4.
G. William Chase Jr. Casimir C. Akoh Ronald R. Eitenmiller 《Journal of the American Oil Chemists' Society》1994,71(8):877-880
A comparison of the responses of an evaporative light-scattering detector (ELSD) and a fluorescence detector for tocopherols
in vegetable oils by high-performance liquid chromatography is presented. The tocopherols were separated from acylglycerols
by gel-permeation chromatography (GPC). The tocopherol fraction was collected off a set of four GPC columns with a mobile
phase of methylene chloride before separation on a normal-phase silica column with a mobile phase of hexane/isopropanol, 99.7∶0.3
(vol/vol). An internal standard of 5,7 dimethyltocol, which was detected by both the ELSD and fluorescence detector, was used
to obtain quantitative data. The fluorescence detector was ten times more sensitive than the ELSD. γ-Tocopherol was the major
tocopherol detected in the vegetable oils studied and ranged from 24.1–93.3 mg/100 g. The amounts of tocopherols found in
the vegetable oils agreed favorably with the literature values. 相似文献
5.
Stoichiometric determination of hydroperoxides in fats and oils by fourier transform infrared spectroscopy 总被引:1,自引:0,他引:1
K. Ma F. R. van de Voort J. Sedman A. A. Ismail 《Journal of the American Oil Chemists' Society》1997,74(8):897-906
A primary Fourier transform infrared (FTIR) spectroscopic method for the determination of peroxide value (PV) in edible oils
was developed based on the stoichiometric reaction of triphenylphosphine (TPP) with hydroperoxides to produce triphenylphosphine
oxide (TPPO). Accurate quantitation of the TPPO formed in this reaction by measurement of its intense absorption band at 542
cm−1 provides a simple means of determining PV. A calibration was developed with TPPO as the standard; its concentration, expressed
in terms of PV, covered a range of 0–15 PV. The resulting calibration was linear over the analytical range and had a standard
deviation of ±0.05 PV. A standardized analytical protocol was developed, consisting of adding ∼0.2 g of a 33% (w/w) stock
solution of TPP in hexanol to ∼30 g of melted fat or oil, shaking the sample, and scanning it in a 100-μm KCI IR transmission
cell maintained at 80°C. The FTIR spectrometer was programmed in Visual Basic to automate scanning and quantitation, with
the reaction/FTIR analysis taking about 2 min per sample. The method was validated by comparing the analytical results of
the AOCS PV method to those of the automated FTIR procedure by using both oxidized oils and oils spiked with tert-butyl hydroperoxide. The two methods correlated well. The reproducibility of the FTIR method was superior (±0.18) to that
of the standard chemical method (±0.89 PV). The FTIR method is a significant improvement over the standard AOCS method in
terms of analytical time and effort and avoids solvent and reagent disposal problems. Based on its simple stoichiometry, rapid
and complete reaction, and the singular band that characterizes the end product, the TPP/TPPO reaction coupled with a programmable
FTIR spectrometer provides a rapid and efficient means of determining PV that is especially suited for routine quality control
applications in the fats and oils industry. 相似文献
6.
Sajid Husain M. Kifayatullah G. S. R. Sastry N. Prasada Raju 《Journal of the American Oil Chemists' Society》1993,70(12):1251-1254
Application of13C nuclear magnetic resonance (NMR) spectroscopy for detection of castor oil (CO) in various edible oils, such as coconut oil,
palm oil, groundnut oil and mustard oil, is described. Characteristic signals observed at δ 132.4, δ 125.6, δ 71.3, δ 36.8
and δ 35.4 ppm, due to C10, C9, C12, C13 and C11 carbons of ricinoleic acid (RA) in CO, were selected for distinguishing it
from edible oils. Quantitative13C NMR spectra of oils were recorded in CDCl3 with a gated decoupling technique. The minimum detection limits for qualitative and quantitative analyses were 2.0 and 3.0%,
respectively. The proposed method is simple, nondestructive and requires no sample pretreatment. Its application to heat-abused
oils has also been demonstrated successfully without any of the interferences observed in most other methods. 相似文献
7.
Simultaneous determination of ascorbyl palmitate and nine phenolic antioxidants in vegetable oils and edible fats by HPLC 总被引:1,自引:0,他引:1
This study describes an HPLC method for the simultaneous determination of ascorbyl palmitate (AP) and synthetic phenolic antioxidants
(SPA) in vegetable oils and edible fats in a single run. To achieve this, citric acid was used in combination with isoascorbic
acid for stabilization of AP in standard and sample solutions and for deactivation of oxidizing agents in the HPLC system.
SPA and AP were directly extracted from samples with methanol containing 1 mg/mL each of citric acid and isoascorbic acid.
HPLC analytical and guard columns were pretreated with 90% methanol/acetonitrile 1∶1 (vol/vol), containing 4 mg/mL each of
citric acid and isoascorbic acid, and 10% water at pH 3, for 30 min. Under these conditions, AP was stable for about 7 h at
room temperature. The relative SD of repeatability for AP (0.5–3.6%) was comparable to that for SPA (0.3–2.8%). Average recovery
from spiked samples was 100% for AP, 98–103% for SPA, and 85% for BHT (up to 90% using double extraction with methanol). 相似文献
8.
A combination of alumina column chromatography and HPLC procedures was developed for the determination of synthetic hydrocarbon-based
thermal heating fluid (trade-marked as Therminol 55TM) in basic oleochemicals. In each run, 3 g of sample solution was loaded onto the alumina (50 g) column and was eluted with
200 mL of hexane. The eluate was then concentrated to 1 mL with the aid of a nitrogen stream prior to HPLC analysis. The HPLC
chromatogram of Therminol 55 was characterized by a humped shape that could not be resolved into individual peaks. The lowest
limit of quantification obtained from various spiked samples was 30 μg/g. The recovery results obtained from the method were
good, ranging from 70 to 80%, whereas the overall CV were all below 10%. The method is simple and thus is ideal for quality
assurance purposes. 相似文献
9.
Analysis of free and esterified sterols in vegetable oils 总被引:2,自引:6,他引:2
T. Verleyen M. Forcades R. Verhe K. Dewettinck A. Huyghebaert W. De Greyt 《Journal of the American Oil Chemists' Society》2002,79(2):117-122
In vegetable oils, phytosterols occur as free sterols or as steryl esters. Few analytical methods report the quantification
of esterified and free sterols in vegetable oils. In this study, esterified and free sterols were separated by silica gel
column chromatography upon elution with n-hexane/ethyl acetate (90∶10 vol/vol) followed by n-hexane/diethyl ether/ethanol (25∶25∶50 by vol). Both fractions were saponified separately and the phytosterol content was
quantified by GC. The analytical method for the analysis of esterified and free sterols had a relative standard deviation
of 1.16% and an accuracy of 93.6–94.1%, which was comparable to the reference method for the total sterol analysis. A large
variation in the content and distribution of the sterol fraction between different vegetable oils can be observed. Corn and
rapeseed oils were very rich in phytosterols, which mainly occurred as steryl esters (56–60%), whereas the majority of the
other vegetable oils (soybean, sunflower, palm oil, etc.) contained a much lower esterified sterol content (25–40%). No difference
in the relative proportion of the individual sterols among crude and refined vegetable oils was observed. 相似文献
10.
Determination of squalene in olive oil using fractional crystallization for sample preparation 总被引:1,自引:0,他引:1
A simple, rapid method for the determination of squalene in virgin olive oil was developed using RP-HPLC with detection at
208 nm. Fractional crystallization from methanol/acetone (7∶3, vol/vol) was applied to obtain squalene in the liquid fraction
of the oil prior to HPLC. Elution of squalene was then carried out isocratically with acetone/acetonitrile (40∶60 vol/vol)
within 11 min. The detection limit was 23 mg/kg, and the limit of quantification 79 mg/kg. The precision of the crystallization
procedure (CV%=3.76, n=7) and the mean recovery (92.5 and 81.5% for the 7,000 and 700 mg/kg levels of addition, respectively) were satisfactory.
The method is easily applicable to fulfill future needs for nutrition labeling. 相似文献
11.
K. H. Lee H. S. Yook J. W. Lee W. J. Park K. S. Kim M. W. Byun 《Journal of the American Oil Chemists' Society》1999,76(8):921-925
The effects of 0, 250, 500, and 1000 ppm (wt/vol) ascorbyl palmitate (AP) on the gamma irradiation-induced oxidation of soybean
oil, cottonseed oil, corn oil, tallow, lard, or linoleic acid either in a solvent mixture (benzene/methanol, 4:1 vol/vol)
or in methanol, was studied immediately after gamma irradiation with a dose of 1–5 kGy. Steady-state kinetic approximation
was used to determine a quenching mechanism and quenching rate constant of AP on the gamma irradiation-induced oxidation of
purified soybean oil in a solvent mixture (benzene/methanol, 4:1 vol/vol). Irradiation greatly increased oxidation of all
oils, as was expected. AP was extremely effective at minimizing oxidation in all oils, and its effectiveness was concentration
dependent. AP showed significantly greater antioxidative activity than α-tocopherol for the reduction of oxidation in all
oils (P<0.05). The steady-state kinetic studies indicated that AP quenched oxygen only to minimize the oxidation of oils. The calculated
total quenching rate of AP was 7.51×107 M−1s−1. The present results clearly show the effective oxygen quenching ability of AP for the reduction of gamma irradiation-induced
oxidation of oils. 相似文献
12.
Glycolipids from edible plant sources were accurately quantified by silica-based, normal-phase high-performance liquid chromatography
using an evaporative light-scattering detector. Five major glycolipid classes (acylated steryl glucoside, steryl glucoside,
ceramide monohexoside, monogalactosyldiacylglycerol, and digalactosyldiacylglycerol) were separated and determined with a
binary gradient system consisting of chloroform and methanol/water (95∶5, vol/vol) without any interference from other lipid
classes and pigments. The described method was applied to 48 edible plants available in Japan including cereals, legumes,
vegetables, and fruits. Examined plant species contained glycolipids in wide concentration ranges, such as 5–645 mg/100 g
tissue. 相似文献
13.
Abdol-Samad Abedi Fatemeh Hemmati Amir Hossein Abedini Abdorreza Mohammadi Masoumeh Moslemi 《Journal of the American Oil Chemists' Society》2021,98(10):969-978
A simple, fast, and reliable liquid–liquid micro-extraction (LLME) method assisted by thermal ultrasound approach was developed for simultaneous determination of synthetic phenolic antioxidants (SPAs) in edible oils by high-performance liquid chromatography equipped with ultraviolet detector (HPLC-UV). The synthetic antioxidants were propyl gallate (PG), butylated hydroxyanisole (BHA), tert-butylhydroquinone (TBHQ), and butylated hydroxyltoluene (BHT). The best extraction conditions were observed were methanol/acetonitrile (1:1, v/v) as the solvent, ultrasound at 4 min, and a temperature of 40°C. The linearity of the calibration curves for the optimum conditions were R2 > 0.989 for all of the SPAs in a range from 1–200 μg ml−1. Relative standard deviation (RSD %) for five analysis was in range of 2.83% to 4.21%. Limit of detection (LOD) and limit of quantification (LOQ) were obtained in range of 0.012–0.06 and 0.04–0.2 μg g−1, respectively. With regard to recovery, a range of 91%–116% was calculated for the spiked edible oils. 相似文献
14.
M. Tasioula-Margari G. Márquez-Ruíz M. C. Dobarganes 《Journal of the American Oil Chemists' Society》1996,73(11):1579-1584
Precipitates enriched in oligomeric triacylglycerides were separated from thermally oxidized olive residue oil, conventional
and high-oleic sunflower oils, and soybean oil by solvent fractionation in methanol/acetone at 4–5°C for 16 h. Different fractionation
conditions were evaluated in an effort to isolate the oligomeric triacylglycerides (OTG). OTG, formed in frying oils upon
heating at low concentations, were not detectable with conventional methods to determine polymeric compounds. The best conditions
found from the different assays were the following: (i) weight of oil sample-to-solvent volume ratio of 1∶20; and (ii) solvent
system methanol/acetone 10∶90 (vol/vol) for monounsaturated oils and 15∶85 (vol/vol) for polyunsaturated oils. Precipitates,
enriched in oligomers, were formed when heated oils and used frying oils contained more than 27% polar compounds, a value
which is widely accepted as the upper limit for use of frying oils. 相似文献
15.
Yaakob B. Che Man A. Rohman T. S. T. Mansor 《Journal of the American Oil Chemists' Society》2011,88(2):187-192
Fourier transform infrared (FTIR) spectra at mid infrared regions (4,000–650 cm−1) of lard and 16 edible fats and oils were compared and differentiated. The chemometrics of principal component analysis and
cluster analysis (CA) was used for such differentiation using FTIR spectra intensities of evaluated fats and oils. With PCA,
an “eigenvalue” of about 90% was achieved using four principal components (PCs) of variables (FTIR spectra absorbances at
the selected frequency regions). PC1 accounted for 44.1% of the variation, while PC2 described 30.2% of the variation. The
main frequency regions that influence the separation of lard from other evaluated fats and oils based on PC1 are 2,852.8 followed
by 2,922 and 1,464.7 cm−1. Furthermore, CA can classify lard into its group based on Euclidean distance. 相似文献
16.
A Comparative Study of the Properties of Selected Melon Seed Oils as Potential Candidates for Development into Commercial Edible Vegetable Oils 总被引:1,自引:0,他引:1
M. B. Mabaleha Y. C. Mitei S. O. Yeboah 《Journal of the American Oil Chemists' Society》2007,84(1):31-36
A comprehensive compositional and characterization study was carried out on five seed oils from varieties of the melons Citrullus lanatus and C. colocynth in order to evaluate their suitability for large-scale exploitation as edible vegetable oils. The oils were extracted by
Soxhlet with a 3:1 mixture of n-hexane/2-propanol with yields that ranged from 24.8 to 30.0% (wt/wt). The refractive indices and relative densities of the
oils fell within the narrow ranges of 1.465–1.469 and 0.874–0.954 g/cm3, respectively. Saponification values ranged between 182.1 and 193.8 mg KOH/g, whilst iodine values (IV) ranged from 95.8
to 124.0 (Wijs). The ranges of the values for free fatty acid (AV), 1.2–4.0 mg KOH/g, peroxide (PV), 1.1–10.9 meq/kg and p-anisidine (p-AV), 0.2–9.0, indicated that secondary oxidation products were barely present. GC analysis gave total unsaturation contents
of 67.93–82.36%, with linoleic acid (18:2) being the dominant fatty acid (55.21–66.85%). The GC results agreed closely with
those from proton NMR analysis of the fatty acid classes. The physicochemical and compositional properties determined in this
study show that the qualities of the test Cucurbitacea seed oils are highly comparable to those of soybean, sunflower and
groundnut seed oils. Therefore, the test melon seed oils could be developed into commercial products to serve as alternate
vegetable oils in Southern and West Africa, the regions where these melons grow. 相似文献
17.
A new analytical method was developed for determining sesamol in sesame seed oil by FTIR spectroscopy. Sesamol was also spiked
at 0 to 1000 mg/kg in freshly refined, bleached, and deodorized palm olein (RBDPOo) and groundnut (peanut) oil. FTIR spectra
were recorded using a transmission (NaCl) cell accessory at room temperature, and the partial least squares regression statistical
method was used to derive calibration models for each oil. The standard errors of calibration were 6.07, 5.88, and 4.24 mg/100
g for sesame, RBDPOo, and groundnut oils, with coefficients of determination (R
2) of 0.9947, 0.9940, and 0.9662, respectively. The calibration models were validated by the “leave-one-out” cross-validation
method, and the R
2 of validation, the standard errors of prediction, and SD of the differences for repeatability and accuracy were computed.
Our results support the premise that FTIR spectroscopy is an efficient and accurate method for determining minor components
such as sesamol in edible oils. 相似文献
18.
A flow injection analysis (FIA) system coupled with a fluorescence detection system using diphenyl-1-pyrenylphosphine (DPPP)
was developed as a highly sensitive and reproducible quantitative method of total lipid hydroperoxide analysis. Fluorescence
analysis of DPPP oxide generated by the reaction of lipid hydroperoxides with DPPP enabled a quantitative determination of
the total amount of lipid hydroperoxides. Use of 1-myristoyl-2-(12-((7-nitro-2-1,3-benzoxadiazol-4-yl)amino) dodecanoyl)-sn-glycero-3-phosphocholine as the internal standard improved the sensitivity and reproducibility of the analysis. Several commercially
available edible oils, including soybean oil, rapeseed oil, olive oil, corn oil, canola oil, safflower oil, mixed vegetable
oils, cod liver oil, and sardine oil were analyzed by the FIA system for the quantitative determination of total lipid hydroperoxides.
The minimal amounts of sample oils required were 50 μg of soybean oil (PV=2.71 meq/kg) and 3 mg of sardine oil (PV=0.38 meq/kg)
for a single injection. Thus, sensitivity was sufficient for the detection of a small amount and/or low concentration of hydroperoxides
in common edible oils. The recovery of sample oils for the FIA system ranged between 87.2±2.6% and 102±5.1% when PV ranged
between 0.38 and 58.8 meq/kg. The CV in the analyses of soybean oil (PV=3.25 meq/kg), cod liver oil (PV=6.71 meq/kg), rapeseed
oil (PV=12.3 meq/kg), and sardine oil (PV=63.8 meq/kg) were 4.31, 5.66, 8.27, and 11.2%, respectively, demonstrating sufficient
reproducibility of the FIA system for the determination of lipid hydroperoxides. The squared correlation (r
2) between the FIA system and the official AOCS iodometric titration method in a linear regression analysis was estimated at
0.9976 within the range of 0.35−77.8 meq/kg of PV (n=42). Thus, the FIA system provided satisfactory detection limits, recovery, and reproducibility. The FIA system was further
applied to evaluate changes in the total amounts of lipid hydroperoxides in fish muscle stored on ice. 相似文献
19.
Antioxidant capacity of extra-virgin olive oils 总被引:1,自引:1,他引:0
Paolino Ninfali Gianfranca Aluigi Mara Bacchiocca Mauro Magnani 《Journal of the American Oil Chemists' Society》2001,78(3):243-247
In this study, the oxygen radical absorbance capacity (ORAC) of vegetable oils was investigated using a spectrofluorometric
method, which measures the protection of the phenolic substances of the oil on the β-phycoerythrin fluorescence decay in comparison
with Trolox. More than 97% of the phenolic substances was extracted from the oil using methanol, and the methanolic extract
was then used for the ORAC and the total phenolics assay. We found a significant correlation between ORAC values of different
olive oils and the total amount of phenolics. For extra-virgin olive oils, maximal ORAC values reached 6.20±0.31 μmol Trolox
equivalent/g, while refined and seed oils showed values in the 1–1.5 μmol Trolox equivalent/g range. Our method is useful
to assess the quality of olive oils and to predict, in combination with the rancidity tests, their stability against oxidation. 相似文献
20.
A new method is presented for determining thecis/trans isomer content of edible vegetable oils. The intensities of Raman lines near 1656 and 1670 cm−1 are associated with thecis andtrans configuration, respectively. A precision of ca. 1% can be obtained in thecis/trans isomer analysis of binary mixtures of methyl esters and triglycerides of monoenes and dienes and of hydrogenated vegetable
oils. The spectroscopic data also provide the iodine value of vegetable oils or isolated fractions with precision for a single
determination of ca. 1%.
Presented at the AOCS meeting, Houston, May 1971.
W. Market. Nutr. Res. Div., ARS, USDA. 相似文献