TAG Profiles of <Emphasis Type="Italic">Jatropha curcas</Emphasis> L. Seed Oil by Easy Ambient Sonic-Spray Ionization Mass Spectrometry

Easy ambient sonic-spray ionization mass spectrometry (EASI–MS) was used to follow the maturation of Jatropha curcas L. seeds via the monitoring of the triacylglycerides (TAG) profile of the oil. Results show that TAG composition is significantly modified during seed development but remains nearly unchanged during storage. The EASI–MS oil analysis performed herein is simple, requires just a tiny droplet of the oil and is performed without any pre-separation or chemical manipulation. The oil from Jatropha gossypifolia L. was also evaluated, and a very different TAG profile was obtained.     

聚环氧丙烷的电喷雾质谱分析

采用电喷雾质谱（ESI—MS）分析得到了聚环氧丙烷（PPO）的一级质谱和二级质谱。通过正负2种离子化模式计算一级质谱中各分子离子峰m／z的差值为58,证实了单体为环氧丙烷（PO）。并在二级质谱中通过对一些化合物碎片峰的解析,得到了PPO的裂解方式。同时利用碎片分析,推断出此PPO起始剂为丙三醇。     

Simple,Rapid Lipidomic Analysis of Triacylglycerols in Bovine Milk by Infusion-Electrospray Mass Spectrometry

Bovine milk is a complex mixture of lipids, proteins, carbohydrates, and other factors of which lipids comprise 3–5% of the total mass. Rapid analysis and characterization of the triacylglycerols (TAG) that comprise about 95% of the total lipid is daunting given the numerous TAG species. In the attached methods paper, we demonstrate an improved method for identifying and quantifying TAG species by infusion-based “shotgun” lipidomics. Because of the broad range of TAG species in milk, a single internal standard was insufficient for the analysis and required sectioning the spectrum into three portions based upon mass range to provide accurate quantitation of TAG species. Isobaric phospholipid interferences were removed using a simple dispersive solid-phase extraction step. Using this method, > 100 TAG species were quantitated by acyl carbon number and desaturation level in a sample of commercially purchased bovine milk.     

Fats and Oils report

Conclusion At current price levels there is a potential demand for an increase of nearly 50 million bushels in domestic crushings and 30 million bushels in exports. Using 57 million bushels for feed, seed and residual this implies a total demand of about 924 million bushels or not much less than the currently indicated production.     

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.     

The Simulacrum System as a Construct for Mass Spectrometry of Triacylglycerols and Others

A construct called a simulacrum is defined that provides all possible solutions to a sum of two mass spectral abundances, based on values (abundances) or ratios of those values. The defined construct is applied to atmospheric pressure chemical ionization mass spectrometry (MS) of triacylglycerols (TAG). A simulacrum has precisely defined components, specifically a simulacrum sum, four Possibilities to Observe, two Cases, and eight solutions. A simulacrum with no restrictions is the First General Form of a Simulacrum. When one value is specified to be 1 (as in MS), the construct is called a Unit Simulacrum, also called the First Specified Form of a Simulacrum. When one value is 1 and no value can be greater than 1 (the two specifications dictated by mass spectrometry), the construct is called the Second Specified Form of a Simulacrum, or the Mass Spectrometry Simulacrum. Simulacra are used with three Critical Ratios calculated from raw abundances in mass spectra of TAG to provide structural information about the degree of unsaturation in TAG, the identity and quantity of regioisomers, and other structural characteristics. Three‐level‐deep nested simulacrum solutions yield the recently reported Updated Bottom Up Solution, from which the protonated molecule, [MH]⁺, and all diacylglycerol‐like fragments, [DAG]⁺, of TAG can be reproduced from the Critical Ratios. Thus, the simulacrum solutions constitute a reduced data set in which more information is provided in fewer values than raw abundances, such that the Critical Ratios constitute a compact library of mass spectra.     

Purity Criteria in Edible Oils and Fats

A review is presented of edible vegetable oil purity criteria developed at the Leatherhead Food Research Association. Most of the work involved accurate determination, by modern GLC techniques, of the fatty acid compositions of oils extracted in the laboratory from oilseeds of known origin and history. All of the main production areas throughout the world were represented in the collection of over 600 samples of commercial oilseeds. No botanial curiosities or hand picked specimens were included as the work related to commercially available edible oils. The fatty acid compositions of the major vegetable oils are reviewed, and the influence this had on the revision of Codex Alimentarius Fats and Oils Specifications is discussed. The development of purity criteria based on the composition of fatty acids at the triglyceride 2-position, triglyceride compositions by high temperature GLC, sterol compositions and tocopherol concentrations are also reviewed. In the case of maize oil a significant new development is the authentication of the oil by stable carbon isotope ratio measurement. The possibilities of this exciting new technique are reviewed in the light of 40 results on maize oils of various origins, together with over 60 results on a selection of other oils and fats.     

Studies on Preparation of Plastic Fats from Non-Traditional Oils and Fats by Interesterification Process

Interesterification reactions of Ricebran oil, mixed with Cottonseed oil, Palm, oil, Mowrah fat and Sal fat in different proportions were studied under various conditions of temperature and time with a view to preparing plastic: fats for edible and industrial uses. It has been possible to obtain a large variety of plastic fat products of various melting ranges which can be used in many segments of the food industry.     

Measurements of Diacylglycerols in Skeletal Muscle by Atmospheric Pressure Chemical Ionization Mass Spectrometry

Diacylglycerol (DAG) is an intermediate lipid involved in the synthesis of phospholipids and triglycerides. As signaling regulators, DAG activate novel protein kinase C leading to decreased response to insulin in skeletal muscle. Alteration of DAG contents correlates with development of metabolic dysregulation in obese and diabetic conditions. Recent advances in lipidomics using mass spectrometry allow expanded measurements of various lipid species. This study describes a rapid measurement of DAG species using the triple quadrupole mass spectrometry using atmospheric pressure chemical ionization in a positive ion mode. DAG in the cells and muscle tissues were separated depending on differences in chain lengths and degree of unsaturation. The limit of detection and quantification for DAG was 0.2 to 17 pmol for this method. When C2C12 cells were treated with palmitate or oleate, we found a 12-fold and 2-fold DAG increase respectively compared to the no-treatment control. In the muscles of obese db/db mice, DAG levels were elevated by 6-fold compared to those of wild-type skeletal muscles. The present analytical method provides a rapid and sensitive quantification of DAG molecular species from various biological samples and can be used to correlate the degree of metabolic dysregulation with lipotoxic metabolites.     

Quantitative Determination of Erucic Acid in Edible Oils and Fats Containing Marine Oils and/or Hydrogenated Fats

A method has been developed for the quantitative measurement of erucic acid in complex samples of oils or fats containing marine oils and/or hydrogenated fats. A two step procedure is proposed: in a first step the constituent fatty acids of the transesterified oil or fat are resolved on a silver-nitrate-impregnated silicagel thin-layer in function of the degree of unsaturation and the double bond localization. Positional isomers migrating slowlier on the thin-layer than erucic acid (e. g. cetoleic acid often present in large amounts in marine oils) are distinctly separated in this way. In a second step components moving ahead of the cetoleic acid (e. g. erucic acid, the added internal standard and geometrical isomers of erucic acid) are scraped off from the thin-layer plate and the erucic acid is determined by gas chromatography on a packed column with a liquid crystal, operated in the nematic phase temperature region, as the stationary phase. In complex samples recoveries of 90 to 102% are reported with overall relative standard deviations of 2.5 to 3%.     

氨苄西林质谱解析及其离子化方式研究

通过对于氨苄西林正离子模式质谱谱图的解析,探讨了氨苄西林的离子化方式和裂解规律。研究表明：氨苄西林存在3种质子化方式,不同的质子化方式所形成分子离子具有不同的裂解方式;质子化的质子具有明显的活性,是质谱进一步裂解的主要原因;离子化方式对于质谱峰的丰度会产生重要影响。本研究为氨苄西林质谱分析和构效关系研究提供了重要的实验基础与理论依据。     

Analysis of Triacylglycerols and Free Fatty Acids in Algae Using Ultra-Performance Liquid Chromatography Mass Spectrometry

To assess the suitability of microalgal strains for biodiesel production the lipid content and composition, especially individual triacylglycerols (TAG) and free fatty acids (FFA) must be determined. In this study, the compositions and concentrations of TAG and FFA were analysed in four halophytic algal species, Dunaliella salina, D. tertiolecta, D. bardawil, and D. granulata. These species were selected as part of a larger screen to identify species suitable for biofuel feedstocks. An accelerated solvent extraction instrument was used for lipids and fatty acid extraction using a dichloromethane–hexane solvent system. Ultra-performance liquid chromatography coupled with mass spectrometry (MS) detection was optimized and applied to the quantitative analysis of TAG and FFA in the different algal extracts. Individual TAG were characterized structurally using direct electrospray ionization (ESI) MS and MS/MS techniques. Cationic adducts (NH₄ ⁺) of TAG were detected and quantified in the positive ESI MS and MS/MS modes, while the negative ESI mode was used for FFA analysis. Over 20 TAG were identified and quantified in the four Dunaliella strains. Analysis of FFA compositions demonstrated that the most abundant FFA in these four algal species were palmitic, linolenic, linoleic, and oleic acids.     

气相色谱-负化学源质谱法测定化妆品中的硝基麝香类化合物

建立了一种用于测定不同化妆品中5种硝基麝香含量的气相色谱-负化学源质谱联用（NCI-GC/MS）方法。通过丙酮/正己烷混合液超声提取化妆品中的硝基麝香,提取液经气相色谱-负化学源质谱联用仪检测,氘代二甲苯麝香内标法定量。方法对化妆品中5种硝基麝香的加标回收率在88.81%～104.92%之间,相对标准偏差（RSD）不大于5.75%,在10.0～500.0μg/L范围内呈现良好的线性关系,灵敏度高,各物质的最低检测限可达到2.0～10.0μg/kg。方法操作简单,选择性好,能有效消除复杂基体干扰,可作为常见化妆品中硝基麝香类化合物含量检测的确证方法。     

Chemical Characterization of Sorbitan Tri-Stearate Commercial Samples and Their Determination in Confectionery Fats by HPLC High-Resolution Mass Spectrometry

Nominal sorbitan tristearate (E492) commercial samples are widely used generally as emulsifiers and particularly as anti-bloom agents in confectionery products. In spite of this generalized use, their qualitative and quantitative evaluation is poorly documented in literature and the relative works go back to the last decades of last century. In the present work, a deep study by HPLC-High Resolution Mass Spectrometry of qualitative composition of five E492 commercial samples was made up showing a very complex pattern of stearic and palmitic acid esters with the sorbitol anhydrides, sorbitan, and isosorbide. A clear distinction of sorbitan mono-, di-, tri-, and tetra-esters, of sorbitol penta- and hexa-esters and isosorbide mono- and di-esters was achieved. Contemporarily, difference in the qualitative pattern between E492 commercial samples coming from different suppliers was established. As a consequence, quantitative evaluation can be reliably obtained by using as calibration standard the same E492 present in real samples. The accuracy and recovery of the method were determined allowing in this way a reliable application to commercial confectionery products. The detailed knowledge of STS composition may be of great help to orient the synthesis conditions in order to modulate its properties as a function of various experimental necessities.     

Identification of Tetraacylglycerols in Lesquerella Oil by Electrospray Ionization Mass Spectrometry of the Lithium Adducts

Tetraacylglycerol (an acylglycerol estolide) contains an acyl chain attached to the hydroxyl group of another acyl chain attached to the glycerol backbone. Lesquerolic acid (Ls, OH¹⁴20:1¹¹) is the main fatty acid in lesquerella oil and may be used industrially for the manufacture of biodegradable industrial products. Electrospray ionization mass spectrometry of the lithium adducts of acylglycerols in the high-performance liquid chromatography fractions from the seed oil of lesquerella (Physaria fendleri) was used to identify thirteen tetraacylglycerols. They were LsLsLsLn, LsLsLsL, LsLs-OH20:2-O, LsLsLsO, LsLsLnLn, LsLsLLn, LsLsOLn, LsLsLL, LsLsOL, LsLsOP, LsLsOO, LsLsLS and LsLsOS. The OH20:2 was auricolic acid (OH¹⁴20:2^11,17). For the four tetraacylglycerols containing one normal fatty acid (non-hydroxy fatty acid), LsLsLsLn, LsLsLsL, LsLs-OH20:2-O and LsLsLsO, the normal fatty acids were all directly attached to the glycerol backbone, not to the hydroxyl group of fatty acids. We propose that the biosynthetic precursors (triacylglycerol acyltransferase) of these four tetraacylglycerols were LsLsLn, LsLsL, LsLsO (Ls-OH20:2-O) and LsLsO individually. LsLsO and Ls-OH20:2-O were equally active as the biosynthetic precursors for LsLs-OH20:2-O. For LsLsLS, linoleate were all attached to the glycerol backbone and LsLsL was proposed to be the biosynthetic precursor. For LsLsOS, stearate were all attached to the glycerol backbone and LsLsS was proposed to be the biosynthetic precursor. For the other seven tetraacylglycerols containing two normal fatty acids, LsLsAB, the biosynthetic precursors could be both LsLsA and LsLsB.     

Triacylglycerol Analysis of Fats and Oils by Evaporative Light Scattering Detection

A high performance liquid chromatography method with evaporative light scattering detection was developed for the analysis of oils and fats, which enabled excellent separation of major and minor triacylglycerol (TAG) species in 33 min, including regeneration of the column. The influence of the mobile phase and temperature on separation and analysis time were evaluated with a cocoa butter standard. The influence of the drift tube temperature and flow of the nebulising gas on the evaporative light scattering detector output signal was investigated by means of a response surface experimental design. Especially the flow of the nebulising gas had a profound effect on the detector signal. An optimal separation was obtained when using a 150 × 3.0 mm C18 column with 3 μm particle diameter at 20 °C and an acetonitrile/dichloromethane gradient at 0.72 mL/min. The maximum response was attained when the ELSD detector was set at the minimum temperature (45 °C) and a gas flow of 1.2 L/min. Finally, the linearity of the detector was investigated. It was found that at very low concentrations, the signal tends to flatten towards zero, giving an underestimation for minor TAG species, especially for oils or fats with a mixed fatty acid composition.