Quantification of the Molecular Species of TAG and DAG in Lesquerella (Physaria fendleri) Oil by HPLC and MS

Ten diacylglycerols (DAG) and 74 triacylglycerols (TAG) in the seed oil of Physaria fendleri were recently identified by high‐performance liquid chromatography (HPLC) and mass spectrometry (MS). These acylglycerols (AG) were quantified by HPLC with evaporative light scattering detector and electrospray ionization mass spectrometry of the lithium adducts of the AG in the HPLC fractions of lesquerella oil. The MS¹ ion signal intensities of molecular ions [M + Li]⁺ in HPLC fractions of an HPLC peak were used to estimate the ratios of AG in the HPLC peak. The ratios of TAG with the same mass in HPLC fractions were estimated by the ratios of the sums of MS² ion signal intensities from the neutral loss of the three fatty acids [M + Li ? FA]⁺. The ratio of DAG with the same mass were estimated by the ratio of the sums of two MS² ion signal intensities [M + Li ? FA]⁺ and [FA + Li]⁺ from the two different FA of a DAG. We have estimated the contents of ten molecular species of DAG and 74 molecular species of TAG in P. fendleri oil using this new method. The content of ten DAG combined was about 1 % and 74 TAG was about 98 %. The contents of DAG in decreasing order were: LsLs (0.25 %), LsLn (0.25 %), LsO (0.24 %), and LsL (0.11 %); and the contents of TAG in decreasing order were: LsLsO (31.3 %), LsLsLn (24.9 %), LsLsL (15.8 %), LsL‐OH20:2 (4.3 %), LsO‐OH20:2 (2.8 %), and LsLn‐OH20:2 (2.5 %).     

Ratios of Regioisomers of the Molecular Species of Triacylglycerols in Lesquerella (Physaria fendleri) Oil Estimated by Mass Spectrometry

The ratios of regioisomers of 72 molecular species of triacylglycerols (TAG) in lesquerella oil were estimated using the electrospray ionization mass spectrometry of the lithium adducts of TAG in the HPLC fractions of lesquerella oil. The ratios of ion signal intensities (or relative abundances) of the fragment ions from the neutral losses of fatty acids (FA) as α‐lactones at the sn‐2 position (MS³) of the molecular species of TAG were used as the ratios of the regioisomers. The order of the preference of FA incorporation at the sn‐2 position of the molecular species of TAG in lesquerella was as: normal FA > OH18 (monohydroxy FA with 18 carbon atoms) > diOH18 > OH20 > diOH20, while in castor was as: normal FA > OH18 > OH20 > diOH18 > triOH18. Elongation (from C₁₈ to C₂₀) was more effective than hydroxylation in lesquerella to incorporate hydroxy FA at the sn‐1/3 positions. The block of elongation in lesquerella may be used to increase the content of hydroxy FA, e.g., ricinoleate, at the sn‐2 position of TAG and to produce triricinolein (or castor oil) for industrial uses. The content of normal FA at the sn‐2 position was about 95 %, mainly oleate (38 %), linolenate (31 %) and linoleate (23 %). This high normal FA content (95 %) at the sn‐2 position was a big space for the replacement of ricinoleate to increase the hydroxy FA content in lesquerella oil. The content of hydroxy FA at the sn‐1/3 positions was 91 % mainly lesquerolic acid (85 %) and the content of normal FA was 6.7 % at the sn‐1/3 position in lesquerella oil.     

Acylglycerols Containing Trihydroxy Fatty Acids in Castor Oil and the Regiospecific Quantification of Triacylglycerols

Ricinoleate, a monohydroxy fatty acid in castor oil, has many industrial uses. Dihydroxy and trihydroxy fatty acids can also be used in industry. We report here the identification of diacylglycerols (DAG) and triacylglycerols (TAG) containing trihydroxy fatty acids in castor oil. The C₁₈ HPLC fractions of castor oil were used for mass spectrometry of the lithium adducts of acylglycerols to identify trihydroxy fatty acids and the acylglycerols containing trihydroxy fatty acids. Two DAG identified were triOH18:1–diOH18:1 and triOH18:0–OH18:1. Four TAG identified were triOH18:1–OH18:1–OH18:1, triOH18:0–OH18:1–OH18:1, triOH18:1–OH18:1–diOH18:1 and triOH18:0–OH18:1–diOH18:1. The structures of these two newly identified trihydroxy fatty acids were proposed as 11,12,13-trihydroxy-9-octadecenoic acid and 11,12,13-trihydroxyoctadecanoic acid. The locations of these trihydroxy fatty acids on the glycerol backbone were almost 100% at the sn-1,3 positions or at trace levels at the sn-2 position. The content of these acylglycerols containing trihydroxy fatty acids was at the level of about 1% or less in castor oil.     

Comparative analysis of triacylglycerols from Olea europaea L. fruits using HPLC and MALDI‐TOFMS

MALDI‐TOFMS and HPLC are two analytical methods that were used to characterize triacylglycerols (TAG) of the Meski, Sayali, and Picholine Tunisian olive varieties. The HPLC chromatograms of the oils showed the presence of 15 TAG species, among which triolein (OOO) was the most abundant (21–48%). In the Sayali cultivar, OOO was the predominant TAG species followed by POO and LOO. However, the minor TAG molecules were represented by LnLO and LnLP. MALDI mass spectra produced sodiated ([M + Na]⁺) and potassiated ([M + K]⁺) TAG molecules; only the major TAG were potassiated [OOO + K] ([OOO + K]⁺, [POO + K]⁺, and [LOO + K]⁺). In contrast to the HPLC chromatograms, the MALDI mass spectra showed 13 peaks of TAG. The major peak was detected at m/z 907, which corresponds to OOO with an Na⁺ adduct. The results from both HPLC and MALDI techniques predict the fatty acid composition and their percentages for each olive variety. Practical applications: TAG are the main components in vegetable oils. These biomolecules determine the physical, chemical, and nutritional properties of the oils. The nutritional benefits of TAG are related to DAG (moderate plasma lipid level) and esterified FA, which are intermediate biosynthetic molecules of TAG. TAG analysis is necessary to discriminate between oils of different origin, since some oils have similar FA profiles. Olive products, oils, and table olives, are the main diet sources of TAG in the Mediterranean countries. In this work, chromatographic and spectrometric methods were used for TAG analysis and characterization of Tunisian olive varieties.     

Identification of TAG and DAG and their FA Constituents in Lesquerella (Physaria fendleri) Oil by HPLC and MS

Castor oil has many industrial uses because of its high content (90 %) of the hydroxy fatty acid, ricinoleic acid (OH¹²18:1⁹). Lesquerella oil containing lesquerolic acid (Ls, OH¹⁴20:1¹¹) is potentially useful in industry. Ten molecular species of diacylglycerols and 74 molecular species of triacylglycerols in lesquerella (Physaria fendleri) oil were identified by electrospray ionization mass spectrometry as lithium adducts of acylglycerols in the HPLC fractions of lesquerella oil. Among them were: LsLsO, LsLsLn, LsLsL, LsLn–OH20:2, LsO–OH20:2 and LsL–OH20:2. The structures of the four new hydroxy fatty acid constituents of acylglycerols were proposed by the MS of the lithium adducts of fatty acids as (comparing to those in castor oil): OH¹²18:2^9,14 (OH¹²18:2^9,13 in castor oil), OH¹²18:3^9,14,16 (OH18:3 not detected in castor oil), diOH^12,1318:2^9,14 (diOH^11,1218:2^9,13 in castor oil) and diOH^13,1420:1¹¹ (diOH20:1 not detected in castor oil, diOH^11,1218:1⁹ in castor oil). Trihydroxy fatty acids were not detected in lesquerella oil. The differences in the structures of these C18 hydroxy fatty acids between lesquerella and castor oils indicated that the polyhydroxy fatty acids were biosynthesized and were not the result of autoxidation products.     

The bottom-up solution to the triacylglycerol lipidome using atmospheric pressure chemical ionization mass spectrometry

Presented here is an approach to representing the data from atmospheric pressure chemical ionization (APCI) mass spectrometry (MS) of triacylglycerols (TAG) using a set of one, two, or three Critical Ratios. These Critical Rations may be used directly to provide structural information concerning the regioisomeric composition of the triacylglycerols (TAG), and about the degree of unsaturation in the TAG. An AAA-type, or Typel, TAG has only one Critical Ratio, the ratio of the protonated molecule, [M+H]⁺, to the DAG fragment ion, [AA]⁺. The Critical Ratio for a Type I TAG is [MH]⁺/Σ[DAG]⁺, and the mass spectrum of a Type I TAG can be reproduced from only this one ratio. An ABA/AAB/BAA, or Type II, TAG has two Critical Ratios, the [MH]⁺/Σ[DAG]⁺ ratio and the [AA]⁺/[AB]⁺ ratio. The [AA]⁺/[AB]⁺ ratio for a single TAG or TAG mixture can be compared with the [AA]⁺/[AB]⁺ ratios of pure regioisomeric standards, and the percentage of each regioisomer can be estimated. The abundance of the protonated molecule and the abundances of the two [DAG]⁺ fragment ions can be calculated from the two Critical Ratios for a Type II TAG. To calculate the abundances, the Critical Ratios are processed through the Bottom-Up Solution to the TAG lipidome. First, Critical Limits are calculated from the Critical Ratios, and then the Critical Ratios are classified into Cases by comparison with the Critical Limits. Once the Case classification is known, the equation for the abundance of each ion in the mass spectrum is given by the Bottom-Up Solution. A Type III TAG has three different FA and three Critical Ratios. The [MH]⁺/Σ/[DAG]⁺ ratio is the first Critical Ratio, the [AC]⁺/([AB]⁺+[BC]⁺) ratio is the second Critical Ratio, and the [BC]⁺/[AB]⁺ ratio is the third Critical Ratio. The second critical ratio for a Type III TAG can be compared with regioisomeric standards to provide an estimate of the percentage composition of the regioisomers. The three Critical Ratios for a Type III TAG can be processed through the Bottom-Up Solution to calculate the four ion abundances that make up the APCI-MS mass spectrum. The Critical Ratios constitute a reduced data set that provides more information in fewer values than the raw abundances.     

Hydroperoxides formed by ferrous ion-catalyzed oxidation of methyl linolenate

An emulsion of methyl linolenate was allowed to oxidize with a catalyst of ferrous sulfate and ascorbic acid. Three oxidation products were isolated, and their hydrogenated derivatives were characterized as the isomeric mixture of methyl monohydroxyoctadecanoate (monoOH), methyl 9,16-dihydroxyoctadecanoate (diOH), and the isomeric mixture of methyl trihydroxyoctadecanoate (triOH). The monoOH isomers and diOH apparently were derived from methyl monohydroperoxyoctadecatrienoate (monoHPO) and methyl dihydroperoxyoctadecatrienoate (diHPO), respectively. Two triOH isomers (the 9,10,12- and 13,15,16-isomers) were thought to be derived from the products containing cyclic peroxide-hydroperoxide structure. 9,16-diHPO was produced by the incubation of monoHPO with ferrous sulfate and ascorbic acid. Moreover, the experiment using¹⁸O₂ demonstrated that mono-HPO yielded 9,16-diHPO by reacting with oxygen molecule. 9,10,13- and/or 9,12,13- and 12,13,16- and/or 12,15,16-triOH isomers were also detected in the hydrogenated derivatives of oxidation products from monoHPO.     

Ratios of Regioisomers of Triacylglycerols Containing Dihydroxy Fatty Acids in Castor Oil by Mass Spectrometry

The triacylglycerols (TAG) containing dihydroxy fatty acids have been recently identified by mass spectrometry in castor oil. These new dihydroxy fatty acids were proposed as 11,12-dihydroxy-9-octadecenoic acid (diOH18:1), 11,12-dihydroxy-9,13-octadecadienoic acid (diOH18:2) and 11,12-dihydroxyoctadecanoic acid (diOH18:0). The ratios of regioisomers of the TAG were estimated by fragment ions from the loss of fatty acids at the sn-2 position as α,β-unsaturated fatty acids by electro spray ionization-mass spectrometry of the lithium adducts (MS³). The content of regioisomeric diOH18:1-OH18:1-diOH18:1 (ABA, with two different fatty acids) was about 92% in the total of stereoisomeric diOH18:1-OH18:1-diOH18:1, OH18:1-diOH18:1-diOH18:1 and diOH18:1-diOH18:1-OH18:1 combined. The approximate contents of other regioisomers were as follows: diOH18:1-OH18:1-OH18:1 (92%), diOH18:1-diOH18:0-diOH18:1 (91%), diOH18:2-OH18:1-OH18:1 (80%) and diOH18:0-OH18:1-OH18:1 (96%). The ratios of regioisomers of TAG (ABC) containing three different fatty acids were estimated as about 7:1:2 (OH18:1:diOH18:1:diOH18:2) and about 7:2:1 (OH18:1:diOH18:0:diOH18:1). Ricinoleate (OH18:1) was predominately at the sn-2 position of TAG (both AAB and ABC) containing dihydroxy fatty acids and ricinoleate. Dihydroxy fatty acids were mainly at the sn-1,3 positions of TAG containing dihydroxy fatty acids and ricinoleate in castor oil. The ratios of the three regioisomers of TAG (ABC) containing three different fatty acids by mass spectrometry are first reported here.     

Effect of cationization reagents on the matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrum of Chinese gallotannins

In this study, Chinese gallotannins were characterized by MALDI‐TOF MS, and effects of cationization reagents on the quality of spectra were investigated. The trideca‐ and tetradeca‐galloyl glucoses were observed in Chinese gallotannins, which could not be detected in earlier studies. When Cs⁺ was used as the cationization reagent, Chinese gallotannins gave a relatively simple MALDI‐TOF spectrum, three series of quasimolecular ions [M + Cs]⁺, [M + 2Cs–H]⁺, and [M + 3Cs–2H]⁺ and a series of metastable ion peaks with minimum abundance were detected. Selection of Na⁺ as the cationization reagent, additional three series of ion peaks including two patterns from the fragmentation and complex 2M adducts [2M + Na]⁺ can be distinguished. In the case of no deionization or addition of cationization reagent to the analyte/matrix, naturally abundant Na⁺ and K⁺ as the cationization reagent, [M + Na]⁺ and [M + K]⁺ molecular ions both appeared in the complicated spectrum. Therefore, we conclude that cationization reagents affect the MALDI‐TOF MS spectrum of Chinese gallotannins significantly. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Identification of steroids by chemical ionization mass spectrometry

Chemical ionization (CI) mass spectra of various natural and synthetic steroids have been studied using methane, isobutane, ammonia, trideuterioammonia and hydroxy anion as reagent gases. The CI spectra of steroids give simple and well characterized ions, which provide information about molecular weight as well as functionalities in the molecules. Trideuterioammonia exchanges rapidly with active hydrogens (e.g., OH, SH, COOH, NH₂) in steroid molecules in the CI reaction and thus provides a convenient means of active hydrogen determination by mass spectrometry. Application of various CI processes to the analysis of steroids and conjugates have been made. Low levels of hydroxycholesterols in biological samples and in cholesterol autoxidation products were identified by the 4 ion patterns, [M+NH₄]⁺, [M−OH+NH₃]⁺, [M−OH]⁺ and [M−H₂ O−OH]⁺, in ammonia CI. The position of hydroxy functions in the cholesterol side chain can be identified from the methane CI of hydroxycholesterol trimethylsilyl (TMS) derivatives. Sterol carboxylic esters can be identified as the ammonium adduct ion of the intact molecule, [M+NH₄]⁺, in ammonia CI. Isobutane and hydroxy anion CI spectra of the steroid esters give abundant ion fragments of both steroids and carboxylic acid moieties. Identification of free bile acids and steroid glycosides without derivatization is also feasible with the CI process when ammonia is used as reagent gas.     

Reversed‐Phase Liquid Chromatography–Quadrupole‐Time‐of‐Flight Mass Spectrometry for High‐Throughput Molecular Profiling of Sea Cucumber Cerebrosides

Usually, the chemical structures of cerebrosides in sea creatures are more complicated than those from terrestrial plants and animals. Very little is known about the method for high‐throughput molecular profiling of cerebrosides in sea cucumbers. In this study, cerebrosides from four species of edible sea cucumbers, specifically, Apostichopus japonicas, Thelenota ananas, Acaudina molpadioides and Bohadschia marmorata, were rapidly identified using reversed‐phase liquid chromatography–quadrupole‐time‐of‐flight mass spectrometry (RPLC‐QToF‐MS). [M + H]⁺ in positive electrospray ionization (ESI) mode were used to obtain the product ion spectra. The cerebroside molecules were selected according to the neutral loss fragments of 180 Da and then identified according to pairs of specific products of long‐chain bases (LCB) and their precursor ions. A typical predominant LCB was 2‐amino‐1,3‐dihydroxy‐4‐heptadecene (d17:1), which was acylated to form saturated and monounsaturated non‐hydroxy and monohydroxy fatty acids with 17–25 carbon atoms. Simultaneously, the occurrence of 2‐hydroxy‐tricosenoic acid (C23:1h) was characteristic of sea cucumber cerebrosides, whereas this molecule was rarely discovered in plants, mammals, or fungi. The profiles of LCB and fatty acids (FA) distribution might be related to the genera of sea cucumber. These data will be useful for identification of cerebrosides using RPLC‐QToF‐MS.     

Capillary supercritical fluid chromatography-atmospheric pressure chemical ionization mass spectrometry of triacylglycerols in berry oils

A capillary supercritical fluid chromatograph (SFC), combined with a triple-quadrupole mass spectrometer (MS) via a liquid chromatography-atmospheric pressure chemical ionization (LC-APCI) interface, was utilized in the analysis of berry oil triacylglycerols. No modification of the commercially available interface was required. Vapor of different solvents, such as methanol, isopropanol, water, or ammonium hydroxide in methanol, was introduced in the sheath gas flow in the APCI source to achieve adequate ionization of triacylglycerols. The separation of triacylglycerols according to acyl carbon number and degree of unsaturation was accomplished on a 20 m × 50 μm i.d. SB-Cyanopropyl-25 column. The resolution of triacylglycerols in the reconstructed ion chromatogram and the sensitivity of the SFC-(APCI)MS system was comparable to or slightly better than that obtained with a flame ionization detector. No baseline drifting was observed during the SFC density programming. Triacylglycerols formed diagnostic [M + H]⁺ and [M - RCOO]⁺ ions with all tested reactant ion solvents except with ammonium hydroxide in methanol, which formed abundant [M + 18]⁺ ions instead of [M + H]⁺ ions. The abundance of the [M + H]⁺ ion increased with increasing degree of unsaturation of a triacylglycerol, whereas the abundance of the [M - RCOO]⁺ ion depended on the regiospecific distribution of the fatty acid moiety between the sn-1/3 positions and the sn-2 position and on the number of double bonds.     

The Updated Bottom Up Solution Applied to Atmospheric Pressure Photoionization and Electrospray Ionization Mass Spectrometry

The Updated Bottom Up Solution (UBUS) was recently applied to atmospheric pressure chemical ionization (APCI) mass spectrometry (MS) of triacylglycerols (TAG). This report demonstrates that the UBUS applies equally well to atmospheric pressure photoionization (APPI) MS and to electrospray ionization (ESI) MS. Critical Ratio 1 (CR1), the [MH]⁺/Σ[DAG]⁺ or [MNH₄]⁺/Σ[DAG]⁺ ratio, does not exhibit the same strongly sigmoidal shape as it does by APCI‐MS. CR1 varies more widely for APPI‐MS than by APCI‐MS, having a maximum value of 11.8, indicating a much greater effect of unsaturation on ion ratios in APPI‐MS than APCI‐MS. Critical Ratio 2, the [AA]⁺/[AB]⁺ ratio for Type II TAG or [AC]⁺/([AB]⁺+[BC]⁺) ratio for Type III TAG, allows quantification of regioisomers of TAG, and shows good agreement for APPI‐MS to regioisomer quantification determined by APCI‐MS. Critical Ratio 3, the [BC]⁺/[AB]⁺ ratio for Type III TAG, reveals new trends relating the degree of unsaturation by APPI‐MS, and shows that structural assignments made by ESI‐MS are in good agreement to APCI‐MS data. In addition to providing valuable structural information, the Critical Ratios also constitute a reduced data set that allows APPI‐MS or ESI‐MS mass spectra to be reconstructed when processed through the UBUS. Quantification by APPI‐MS of vitamin D in the gelcaps gave values of 42.90 ± 0.83 μg, or 1716 ± 33 international units, in good agreement with APCI‐MS.     

Identification of diacylglycerols and triacylglycerols in a structured lipid sample by atmospheric pressure chemical ionization liquid chromatography/mass spectrometry

Atmospheric pressure chemical ionization liquid chromatography/mass spectrometry was used in the identification of diacylglycerol and triacylglycerol (TAG) molecular species in a sample of a structured lipid. In the study of acylglycerol standards, the most distinctive differences between the diacylglycerol and TAG molecules were found to be the molecular ion and the relative intensity of monoacylglycerol fragment ions. All saturated TAG ranging from tricaproin to tristearin, and unsaturated TAG including triolein, trilinolein, and trilinolenin, had ammonium adduct molecular ions [M+NH₄]⁺. Protonated molecular ions were also produced for TAG containing unsaturated fatty acids and the intensity increased with increasing unsaturation. Diacylglycerol fragment ions were also formed for TAG. The ammonium adduct molecular ion was the base peak for TAG containing polyunsaturated fatty acids, whereas the diacylglycerol fragment ion was the base peak for TAG containing saturated and monounsaturated medium- and long-chain fatty acids; the relative intensities of the ammonium adduct molecular ions were between 14 and 58%. The most abundant ion for diacylglycerols, however, was the molecular ion [M−17]⁺, and the relative intensity of the monoacylglycerol fragment ion was also higher than that for TAG. These distinctive differences between the diacylglycerol and TAG spectra were utilized for rapid identification of the acylglycerols in the sample of a structured lipid.     

Identification of Acylglycerols Containing Dihydroxy Fatty Acids in Castor Oil by Mass Spectrometry

Ricinoleate, a monohydroxy fatty acid, in castor oil has many industrial uses. Dihydroxy fatty acids can also be used in industry. The C₁₈ HPLC fractions of castor oil were analyzed by electrospray ionization mass spectrometry of lithium adducts to identify the acylglycerols containing dihydroxy fatty acids and the dihydroxy fatty acids. Four diacylglycerols identified were diOH18:1-diOH18:1, diOH18:2-OH18:1, diOH18:1-OH18:1 and diOH18:0-OH18:1. Eight triacylglycerols identified were diOH18:1-diOH18:1-diOH18:1, diOH18:1-diOH18:1-diOH18:0, diOH18:2-diOH18:1-OH18:1, diOH18:1-diOH18:1-OH18:1, diOH18:1-diOH18:0-OH18:1, diOH18:2-OH18:1-OH18:1, diOH18:1-OH18:1-OH18:1 and diOH18:0-OH18:1-OH18:1. The locations of fatty acids on the glycerol backbone were not determined. The structures of these three newly identified dihydroxy fatty acids were proposed as 11,12-dihydroxy-9-octadecenoic acid, 11,12-dihydroxy-9,13-octadecadienoic acid and 11,12-dihydroxyoctadecanoic acid. These individual acylglycerols were at the levels of about 0.5% or less in castor oil and can be isolated from castor oil or overproduced in a transgenic oil seed plant for future industrial uses.     

Water-retaining ability of diacylglycerol

The water-in-oil emulsification characteristics and the adsorption properties of DAG at the oil/water interface were investigated for DAG having different FA compositions. The water-retaining ability of DAG is dependent on the FA composition but is not dependent on the interfacial tension at the oil/water interface in a simple way. The water-retaining ability is very different between uni-chain DAG (two FA have the same chain length) and complex-chain DAG (one FA is oleic acid and the other has a shorter alkyl chain). Uni-chain DAG, having long FA chains (R=C₁₂ or C_18∶1) have the ability to emulsify water at the volume fraction of 80% (ϕ80%), but uni-chain DAG with short or medium chain-length FA (R=C₃, C₄, C₆, C₈) show little ability to retain water. For complex-chain DAG, all the DAG studied here (R₁=C_18∶1, R₂=C₂−C₁₂) have the ability to emulsify water at ϕ80%. The stability of the emulsions, however, varies with the chain length of the R₂ FA (R₂ stability order: C₂, C₃>C_18∶1, C₁₀>C₈>C₄, C₆). The relationship between the water-retaining ability and the molecular structure of DAG is discussed from the viewpoint of intra- and intermolecular interactions between the FA chains.     

Analysis of the seed oil of Heisteria silvanii (Olacaceae)—A rich source of a novel C18 acetylenic fatty acid

Besides some usual fatty acids (FA), two conjugated ene-yne acetylenic FA [trans-10-heptadecen-8-ynoic acid (pyrulic acid) (7.4%), and trans-11-octadecen-9-ynoic acid (ximenynic acid) (3.5%)], a novel ene-yne-ene acetylenic FA [cis-7, trans-11-octadecadiene-9-ynoic acid (heisteric acid) (22.6%)], and 9,10-epoxystearic acid (0.6%) could be identified in the seed oil of Heisteria silvanii (Olacaceae). Two further conjugated acetylenic FA [9,11-octadecadiynoic acid (0.1%) and 13-octadecene-9,11-diynoic acid (0.4%)] were identified tentatively by their mass spectra. The FA mixture has been analyzed by gas chromatography/mass spectrometry (GC/MS) of their methyl ester and 4,4-dimethyloxazoline derivatives. The structure of heisteric acid was elucidated after isolation via preparative silver ion thin-layer chromatography and by various spectroscopic methods [ultraviolet; infrared; ¹H, ¹³C nuclear magnetic resonance (NMR); ¹H−¹H and ¹H−¹³C correlation spectroscopy]. To determine the position of the conjugated ene-yne-ene system, the NMR spectra were also measured after addition of the lanthanide shift reagent Resolve-Al EuFOD^TM. Furthermore, the triyglyceride mixture was analyzed by high-temperature GC and high-temperature GC coupled with negative chemical ionization MS. A glass capillary column coated with a methoxy-terminated 50%-diphenyl-50%-dimethylpolysiloxane was used for the separation of the triacylglycerol (TAG) species. No evidence of decomposition of the TAG species containing conjugated ene-yne-ene FA was observed. Twenty-six species of the separated TAG were identified by means of their abundant quasi molecular ion [M−H]⁻ and their corresponding carboxylate anions [RCOO]⁻ of the fatty acids, respectively. The major molecular species of the TAG were found to be 16:0/18:1/18:1, 16:0/18:1/18:3 (heisteric acid), 17:2 (pyrulic acid)/18:1/18:1, 18:1/18:1/18:3 (heisteric acid). The TAG containing acetylenic FA showed an unexpected increase of the retention time in comparison to the TAG containing usual FA, thus making the prediction of the elution order of lipid samples containing acetylenic FA difficult.     

Poly[poly(oxypropylene) phosphate] macroionophores for transport and separation of cations in a hybrid: Cation‐exchange polymer and liquid membrane system

Poly[poly(oxypropylene) phosphate]s (PPOPP, M_n = 5800, 8100, 10,400), with different POP units (400, 1200, 2000), were synthesized and applied as cation‐selective macroionophores in a multimembrane hybrid system (MHS). The solution of PPOPP in dichloroethane formed the flowing liquid membrane (FLM) circulating between two polymer cation‐exchange membranes, and subsequently, between two polymer‐made pervaporation (PV) membranes. It was found that the PPOPP macroionophores activate the preferential transport of Zn²⁺ cations from aqueous solutions containing competing Cu²⁺, Ca²⁺, Mg²⁺, K⁺, and Na⁺ cations. The following separation orders were observed for PPOPPs with POP‐400 and POP‐1200: Zn²⁺ > Cu²⁺ ? Ca²⁺, Mg²⁺, K⁺, Na⁺, and for PPOPP with POP‐2000: Zn²⁺ > Cu²⁺,Ca²⁺ ? Mg²⁺, K⁺, Na⁺. Always, the particular cations are separated as: Zn²⁺ > Cu²⁺, Ca²⁺ > Mg²⁺, and K⁺ > Na⁺. The properties of PPOPPs were compared to respective transport and separation characteristics corresponding to those of respective poly(propylene glycol)s and poly(oxypropylene) bisphosphates. The results of investigation indicate that the bifunctional character of PPOPPs is caused by the presence of ionizable groups and probably pseudocyclic POP structures. By comparing the separation of cations in the simple MHS[FLM] system and the system supported by pervaporation unit [MHS[FLM‐PV] it was found that continuous dehydration of an organic FLM improves the system overall performance. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1436–1445, 2004     

Li1.6Mn1.6O4/PVDF多孔膜的制备及提锂性能

自制锂离子筛前驱体Li_1.6Mn_1.6O₄，并将Li_1.6Mn_1.6O₄粒子与高分子树脂PVDF杂化制膜，研究了膜经稀盐酸抽锂后对锂的吸附性能以及多次吸附与脱附性能等。结果表明，膜M-10-55[Li]采用0.5 mol·L^-1 HCl溶液抽锂约2 h锂的脱出基本达到平衡，Li⁺的洗脱率在95%左右，锰的溶损率为3.5%左右。抽锂后得M-10-55[H]对富锂溶液中锂的吸附约12 h达平衡，对锂的吸附容量较高为41 mg·g^-1，在第5次吸附时对锂的提取量为35 mg·g^-1左右。相比于Na⁺、K⁺、Mg²⁺、Ca²⁺，该膜对Li⁺表现出较好的选择性，对于从海水、盐湖卤水等液态锂资源中提取锂有很大的开发潜力。     

Ethylene carbonate—propylene carbonate mixed electrolytes for lithium batteries

Electrolytic characteristics of propylene carbonate (PC)ethylene carbonate (EC) mixed electrolytes were studied, compared with those in PC electrolytes. Conductivity and Li charge—discharge efficiency values increased with EC contents increasing. For example, 1 M LiClO₄ECPC (EC mixing molar ratio; [EC]/[PC] = 4) showed the conductivity of 8.5 ohm^?1 cm^?1, which value was 40% higher than that in PC. Also, 1 M LiClO₄ECPC([EC]/[PC] = 5) showed the Li charge—discharge efficiency of 90.5% at 0.5 mA cm^?2, 0.6 C cm^?2, which value was ca. 25% higher than that in PC. ECPC mixed electrolytes were considered to be practically available for ambient lithium batteries in regard to the high Li⁺ ion conductivity and also high Li charge—discharge efficiency.