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1.
Neutral lipid classes were separated with normal-phase high-performance liquid chromatography, and mono- and diglycerides
were determined with an evaporative light-scattering detector (ELSD). The 1,3-diacylglycerols were resolved from the 1,2-diacylglycerol
positional isomers, although some 1,3-diacylglycerols of low molecular weight interfered with the 1,2-diacylglycerols of high
molecular weight. For monoglycerides, the separations between 1-(and 3-)acyl and 2-acylglycerols were optimized only between
those pairs with identical fatty acyl groups. Samples were dissolved in a solvent mixture and analyzed without derivatization.
The results (monoglyceride) obtained from this method agreed well with those derived from gas chromatographic and supercritical
fluid chromatographic methods. The universal nature of the ELSD makes this method applicable to oils and emulsifiers containing
both saturated and unsaturated fatty acyl moieties. 相似文献
2.
A new analytical procedure for the determination of alcohol ethoxylates (AE) in environmental samples such as influents, effluents
and sludge from waste water treatment plants (WWTPs) was developed. Although some work had been previously published on the
detection of AE in water samples, this is the first paper that deals with AE in sludge. Alcohol ethoxylates were removed from
water samples by sorption on polymeric discs followed by extraction with methanol. The methanol extracts were cleaned up with
two alumina solid-phase extractions (SPE) at different conditions of solvent polarity, one before and the other after derivatization
with naphthoyl chloride. A final polishing step was carried out on a Florisil SPE column. Liquid chromatography/mass spectrometry
with electrospray ionization was used to quantify AE as naphthoyl derivatives. The detection limits for AE ethoxymers range
from 0.07 to 0.005 μg/L in water samples. The method was applied to an Italian WWTP in order to follow the fate of AE during
treatment, AE concentrations of 839 μg/L, 0.46 μg/L and 10.6 mg/kg were respectively found in the inlet, outlet and sludge
samples. AE removals of each ethoxymer in the plant were in the range 99.6–100% and no difference was observed between high
or low-mole ethoxymers and between AE with odd or even carbon chain lengths. An overall 99.7% removal was also determined
on the mass balance of AE in the inlet, the outlet, and sludge of the plant. 相似文献
3.
A high performance liquid chromatography (HPLC) method using adsorption columns combined with linear gradient elution has
been developed for the determination of ethylene oxide (EO) distribution in nonionic surfactants. The quantitative ethoxylate
adduct distribution in single-carbon-number and mixed-carbon-number primary alcohol-based samples can be obtained. The HPLC
method is also applicable for determining the molar EO distributions in diverse ethylene oxide adduct compounds such as alkylphenol
ethoxylates, branched alcohol ethoxylates and secondary alcohol ethoxylates. Nonionic surfactant samples containing adducts
up to 25 mol have been successfully separated and the individual adducts quantitated. 相似文献
4.
High-performance liquid chromatography (HPLC) for analysis of phospholipids has traditionally employed ultraviolet detection
of the eluted compounds. The evaporative laser light-scattering detector (ELSD) offers new opportunities for quantitative
analysis of lipids. Phospholipids were isolated from crude and degummed oils prepared from soybeans subjected to storage at
high moisture content. Analytical and preparative separations of phospholipids by normal-phase HPLC were accomplished. Major
class fractions were analyzed by transmethylation and capillary collumn chromatography for fatty acid composition, and by
reverse-phase C-18 HPLC (RP-HPLC) for molecular species composition. The RP-HPLC-ELSD system was limited to the analysis of
phosphatidylcholine and phosphatidylethanolamine. 相似文献
5.
Alcohol ethoxylates (AE) are commonly used nonionic surfactants with widespread adoption in consumer and industrial applications. The toxicology profile of this general class of molecules has been extensively reported previously. This report serves to make accessible previously unpublished toxicological data from 59 toxicology studies on AE produced from branched and semilinear alcohols produced by ExxonMobil, with alcohol backbones ranging from C9 to C15. Information on acute oral toxicity, acute dermal toxicity, genetic toxicity, skin irritation, eye irritation, skin sensitization, and oral repeat-dose toxicity are presented here. These data significantly enrich the database on the toxicity of branched AE and support that the degree of branching presents no unique toxicological hazards in relation to that of semilinear AE in this report, as well as in comparison with similar data published on a range of linear, semilinear, and branched AE. 相似文献
6.
An improved method for the analysis of phospholipids by normal-phase HPLC is described. Addition of methanol and acetonitrile
to a gradient based on 2-propanol/hexane/water promoted a rapid separation of major classes of bovine surfactant phospholipids
(PL) by using a conventional silica column. The use of an ELSD permitted an accurate analysis of a mixture of PL. Calibration
curves were linear within the range of 5–40 μg with detection limits below 1 μg for PE and PC, and CV ranged from 0.6 to 9.6%.
PL present in surfactant homogenates were separated by a solid-phase extraction (SPE) procedure before HPLC analysis. This
methodology gave a recovery of 95% and combined SPE-HPLC and quantification of biological PL within a 30-min run. The use
of ELSD detection of the eluted compounds was precise, linear, and sensitive. 相似文献
7.
In enhanced oil recovery applications, surfactants are injected into reservoirs along with polymers and salts. The effluents eluted from lab experiments and field tests are analyzed by HPLC methods using an evaporative light scattering detector (ELSD) detector. When the surfactant concentrations are less than 100 ppm, HPLC methods are inaccurate. A novel two-phase titration method is developed where surfactant concentrations can be quantified using a calibration curve constructed with UV/vis absorption. This method can analyze surfactant concentrations 5–80 ppm where dilution eliminates any high-salinity interferences with the absorption measurements. The method is based on formation of a dye-surfactant complex and the light absorption of the complex has a linear correlation with the surfactant concentration. Anionic surfactant concentrations lower than 100 ppm can be accurately quantified using this method with methylene blue. The method was also developed for low concentrations (<50 ppm) of cationic surfactants using methyl orange and indigo carmine. The indigo carmine method can be used without the use of an organic phase. All methods are applicable at salinities up to 3 wt%. Both the methylene blue method and the methyl orange method can be used to detect zwitterionic surfactants. These methods can be used in the presence of polymers without any prior treatments. 相似文献
8.
The biodegradation of alcohol ethoxylates (AE) and alkylphenol ethoxylates (APE) is reviewed. Biodegradation test methods,
ranging from laboratory tests to full-scale waste treatment plant studies are described for these surfactants. A comparison
is made between primary and ultimate biodegradability criteria and the limitations of the various analytical methods used
in these determinations are discussed. The most recently published data suggest sewage bacteria degrade AE by a mechanism
which is different from that by which APE degrades. The use of radiolabeled surfactants to elicit more detailed information
about the biodegradation mechanisms of AE is described. The role of biodegradation on the impact of surfactants released to
the environment is assessed, and future environmental concerns for nonionics are considered. 相似文献
9.
We have developed a new method for determining ethanolamine plasmalogen contents in marine invertebrates. This quantification method involves derivatization of ethanolamine glycerophospholipid (EtnGpl) subclasses, alkenylacyl (plasmalogen), diacyl, and alkylacyl subclasses, by enzyme treatment and acetylation, followed by separation and detection by high‐performance liquid chromatography (HPLC) with evaporative light‐scattering detection (ELSD). This method enabled complete separation of the subclasses, and the limit of detection for plasmalogen was 200 ng (260 pmol). The peak area of plasmalogen by ELSD was unaffected by the degree of unsaturated fatty acids in EtnGpl, in contrast to ultraviolet (UV) detection. Thus, this method enables accurate determination of plasmalogen contents in various species containing marine products possessing abundant polyunsaturated fatty acids (PUFA). The method developed here was applied to marine invertebrates available in Japan. The examined marine invertebrates showed a wide range of plasmalogen contents ranging from 19 to 504 μmol/100 g wet wt. The plasmalogen levels in samples except those of class Cephalopoda and Crustacea were more than 60 mol% of EtnGpl. 相似文献
10.
Blends of alcohol ethoxysulfates (AES) and alcohol ethoxylates (AE) at high active matter content (90%) have been prepared.
These blends contain no solvents other than water and have sufficiently low viscosities enabling the pumping of them from
storage vessels to mix tanks. In addition, they may be diluted into aqueous solutions with less gel formation tendencies than
shown by AE or AES alone. Specific AE/AES blend ratios, alkyl and polyoxyethylene chain lengths are important selection parameters
for achieving desired rheological properties.
This paper was presented at the 79th American Oil Chemists’ Society Annual Meeting, May 1988, Phoenix, Arizona. 相似文献
11.
Polyols with terminal primary alcohol functionalities were obtained from canola oil via an ozonolysis and hydrogenation process.
A high performance liquid chromatography (HPLC) method with evaporative light scattering detection (ELSD) was developed for
separating and quantifying the polyol products. Linear calibration curves were obtained for the mono-ol, diol and triol components
with correlations ( r
2) above 0.98. According to the standard curve, the content of mono-ol, diol and triol can be obtained from their HPLC-ELSD
chromatograms. 相似文献
12.
This work was undertaken to develop a relatively simple, rapid, reproducible and accurate method for measuring the ethylene
oxide distribution, overall ethylene oxide ratio, and percent free alcohol in ethoxylated alcohols. Using single isomer ethoxylate
standards comprised of from one to eight ethylene oxide units per alcohol, a response factor correlation for the flame ionization
detector on a supercritical fluid Chromatograph was established. Response factors for ethoxylates with higher than eight ethylene
oxide units were estimated by extrapolation of this correlation. Supercritical fluid Chromatographic separation of ethoxylates
was accomplished using a density-programmed carbon dioxide mobile phase and a poly (dimethylsiloxane) coated open tubular
column. The validity and accuracy of this method was demonstrated by comparing its results for unreacted alcohol levels, ethylene
oxide-to-alcohol average ratios, and weights of samples injected relative to internal standards with values measured independently
by standard methods. In addition, supercritical fluid Chromatographic determinations of ethylene oxide molar distributions
are in agreement with theoretical Weibull-Nycander distributions.
Presented in part at the AOCS Annual Meeting in PHoenix, AZ, in May 1988. 相似文献
13.
In the study of chiral biologically active compounds such as pheromones, the analysis of the stereoisomer composition is essential to gain more insight into their stereochemical diversity, which affects the pheromone communication channels and therefore the diversification of species. This mini-review summarizes the development of fluorescence derivatization reagents for high-performance liquid chromatographic (HPLC) determination of the absolute configuration and stereoisomer composition of natural products with a chiral branched alkyl chain. The diastereomeric separation of anteiso fatty acids bearing a branched methyl group up to the C-26 position was achieved by reversed-phase HPLC under very low column temperature conditions using (1S,2S)-2-(2,3-anthracenedicarboximido)cyclohexanol as a derivatization reagent, enabling fluorescent detection of these compounds at femtomole levels. This method was also applicable to chiral alcohols and amines with chiral branched methyl groups using similar reagents containing a carboxyl group. These reagents were successfully applied to determine the absolute configurations and stereoisomer composition of the chiral alkyl chain of natural compounds including some insect pheromones, miyakosyne A, and plakoside A. The combination of these reagents and two-dimensional HPLC constitutes a very powerful tool for the analysis of the stereoisomers of natural crude samples. Furthermore, the analysis of some natural bioactive substances using this method demonstrated that natural substances are not always optically pure, consisting instead of stereoisomer mixtures exhibiting stronger activity than optically pure enantiomers. These results cast doubts on the concept of biological homochirality and demonstrate that natural pheromones do not always show the highest activity among all stereoisomers. 相似文献
14.
The metabolism of 13 S-hydroperoxy-9 Z,11 E,15 Z-octadecatrienoic acid was investigated in a crude enzyme extract from mung bean seedlings ( Phaseolus radiatus L.). Hydroperoxide-metabolizing activity was mainly due to a hydroperoxide lyase and, to a lesser extent, to an allene oxide
synthase and a peroxygenase. Oxylipins originating from hydrolysis and cyclization of the allene oxide synthase product 12,13-epoxy-9 Z,11,15 Z-octadecatrienoic acid and from peroxygenase catalysis were identified by high-performance liquid chromatography (HPLC) particle
beam-mass spectrometry (PB-MS) and quantified by normal-phase HPLC with an evaporative light-scattering detector (ELSD). An
advantage of this methodology was the possibility to avoid extensive derivatization procedures commonly used for the gas chromatographic
analysis of oxylipins. Owing to a comparable sample inlet system, the ELSD served an important analytical pilot function for
the PB-MS: Qualitatively identical chromatographic patterns were obtained with both detection systems. The HPLC system enabled
the separation of methyl 12-oxo-phytodienoate, methyl 11-hydroxy-12-oxo-9 Z,15 Z-octadecadienoate, methyl 12-oxo-13-hydroxy-9 Z,15 Z-octadecadienoate, methyl 9-hydroxy-12-oxo-10 E,15 Z-octadecadienoate, methyl 13-hydroxy-9 Z,11 E,15 Z-octadecatrienoate, methyl 15,16-epoxy-13-hydroxy-9 Z,11 E,15 Z-octadecatrienoate, and methyl 13-hydroperoxy-9 Z,11 E,15 Z-octadecatrienoate on a Lichrospher DIOL column within 33 min. Compared with a diode array detector, the ELSD proved to be
more sensitive, in the case of methyl 12-oxo-13-hydroxy-9 Z, 15 Z-octadecadienoate by a factor of about 15. In addition, volatile metabolites were analyzed by capillary gas chromatography.
The yield of the hydroperoxide lyase product 2 E-hexenal was 49%, whereas the sum of oxylipins reached about 15%. 相似文献
15.
Because of the positive health effects of phytosterols, phytosterol-enriched foods and foods containing elevated levels of
natural phytosterols are being developed. Phytosterol contents in cereals are moderate, whereas their levels in the outer
layers of the kernels are higher. The phytosterols in cereals are currently underutilized; thus, there is a need to create
or identify processing fractions that are enriched in phytosterols. In this study, pearling of hulless barley and rye was
investigated as a potential process to make fractions with higher levels of phytosterols. The grains were pearled with a laboratory-scale
pearler to produce pearling fines and pearled grains. Lipids were extracted by accelerated solvent extraction, and nonpolar
lipids were analyzed by normal-phase HPLC with ELSD and UV detection. Total sterol analyses were performed by GC. After a
90-s pearling, the amounts of pearling fines from hulless barley and rye were 14.6 and 20.1%, respectively, of the original
kernel weights. During pearling, higher levels of phytosterols and other lipids were fractionated into the fines. The contents
of free sterols and sterols esterified with FA in the fines were at least double those in the whole grains. Pearling fines
of hulless barley and rye contained >2mg/g phytosterol compounds, which makes them a good source of phytosterols and thus
valuable raw materials for health-promoting foods. 相似文献
16.
概述了壬基酚、辛基酚、壬基酚聚氧乙烯醚和辛基酚聚氧乙烯醚的性质、应用情况和安全性评价;简单介绍了国内外与洗涤用品中烷基酚和烷基酚聚氧乙烯醚相关的法规和标准;综述了一些标准和论文中关于洗涤剂和化妆品中壬基酚、辛基酚、壬基酚聚氧乙烯醚和辛基酚聚氧乙烯醚的检测方法,并对一些检测方法所采用的技术和注意事项进行了重点说明。 相似文献
17.
Application of the evaporative light-scattering principle to quantitative high-performance liquid chromatography (HPLC) analyses
of plant membrane lipids has received little study. Light-scattering detection response curves were generated for nine classes
of plant membrane phospholipid and glycolipids. Quantitative results obtained by HPLC/light-scattering detection and conventional
lipid analytical methods (thin-layer chromatography and lipid-P assay) were in close agreement, confirming the reliability
of HPLC/evaporative light-scattering detection (ELSD) analyses. Only three of the nine plant lipid classes gave linear detector
response functions above 10 μg injected lipid mass. This finding contradicts earlier precepts involving light-scattering detection
of lipids. At a given mass, appreciable variation in ELSD signal intensity and detection limit was found to exist among the
various plant membrane lipid classes. The variation in detector response among plant lipid classes is an important consideration
in achieving accurate quantitative results in plant lipid analyses. 相似文献
18.
The characterization of alcohol ethoxylates (AE) to determine ethylene oxide (EO) adduct distribution has been studied in
our laboratory for many years by using high-performance liquid chromatography-mass spectrometry (LC-MS). This paper describes
the LC-MS approach being used to analyze both nonderivatized and derivatized AE. We conclude that the best way to determine
EO adduct distribution is by first converting the AE to alcohol ethoxy sulfates (AES) and then by using LC-MS with electrospray
ionization in the negative ion mode. A convenient laboratory technique for converting small-scale samples of AE to AES has
been discovered and is reported herein. Several examples of EO adduct distribution determined by this method are presented
for both linear and isomeric AE samples. 相似文献
19.
Previous work established a high correlation between the potential environmental toxicity of oxyethylenated nonionic surfactants
and the average degree of ethoxylation. For this reason, it was considered of interest to determine whether a narrow- or broad-range
homolog distribution of polydisperse commercial alcohol ethoxylates would influence toxicity. Ethoxylated fatty alcohols,
both linear and branched, were synthesized with sodium hydroxide or an unconventional calcium-based catalyst. Toxicity tests
were run on Daphnia magna and luminescent marine bacteria. Toxicity of ethoxylated alcohols as a function of type of ethoxylate homolog distribution
(narrow or broad) and average degree of polyaddition is analogous for both test species. However, narrow-range ethoxylates
show lower toxicity values than conventional ethoxylates. Differences in toxicity values between broad- and narrow-range ethoxylates
depend on the degree of ethoxylation. 相似文献
20.
Using a 1,3-regioselective lipase as a catalyst, soybean oil and olive oil were interesterified with the short-chain triacylglycerol
tributyrin (1,2,3-tributyrylglycerol) to produce mixtures of structured triacylglycerols (SL-TAG). The SL-TAG were purified
by column chromatography and analyzed by both normal-phase (silica column; NP SIL) and reversed-phase [octadecyl silane (ODS) column] high-performance liquid chromatography (HPLC). Individual SL-TAG molecular
species were detected by evaporative light-scattering detection, and characterized by mass spectrometry. NP SIL HPLC successfully separated the newly synthesized SL-TAG into two groups of TAG: one composed of one butyryl group and two
long-chain fatty acyl groups (from soybean or olive oil); the second was composed of two butyryl groups and one long-chain
fatty acyl group. The SL-TAG species were further analyzed by reversed-phase HPLC which gave a more detailed separation of
the TAG species present in the two SL-TAG. 相似文献
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