Separation of wax esters from olive oils by high-performance liquid chromatography

To detect adulteration of olive oil with solvent-extracted oils, the determination of the wax ester content has become more important during recent years. Hence, a greater number of wax ester analyses need to be performed by quality control laboratories. The most common method in use requires a liquid chromatographic (LC) separation of the less polar fraction, which contains the wax esters, from the glyceride matter on a hand-filled silica gel column. The aim of this project was to verify the possibility of replacing LC with high-performance liquid chromatography by taking advantage of the greater reliability and repeatability of this technique, as well as of the possibility of making the separation automatic. The paper describes how to perform the analysis and the statistical test that was carried out; furthermore, a comparison has been made with the usual method and results are in good agreement.     

利用气相色谱-质谱联用技术测定微藻油脂的组成

采用超临界CO2萃取技术从微藻粉中提取油脂,微藻油脂经预处理后,采用气相色谱-质谱联用技术分析微藻油脂的组成成分.测定结果显示微藻油脂中主要有20种组分,主要是C12到C24的化合物,其中酯类化合物较多,以邻苯二甲酸二异辛酯居多,质量分数占70％以上,其次分别为反式角鲨烯、软脂酸等.     

蒸馏废飞机除冰液所得馏分的气相色谱-质谱分析

采用气相色谱-质谱联用技术对蒸馏废飞机除冰液所得馏分进行分析,分离出了3个峰,鉴定出馏分中被蒸出的除冰液有效成分为乙二醇、2-辛酮和2-辛醇,利用峰面积归一化法确定各组分的相对含量为乙二醇占85.78%,2-辛酮占1.54%,2-辛醇占12.68%。     

气相色谱-质谱法测定化妆品中16种邻苯二甲酸酯

建立了气相色谱-质谱法同时测定化妆品中16种邻苯二甲酸酯的分析方法。在邻苯二甲酸酯质量浓度为0.1 mg/L~100 mg/L范围内,该方法测得的峰面积值与邻苯二甲酸酯的质量浓度的线性关系良好。线性相关系数均大于0.99,检出限为0.5 mg/kg,回收率为83.3%~121.8%,相对标准偏差为0.5%~6.4%。     

气相色谱-质谱联用法测定丁二烯中对叔丁基邻苯二酚含量

采用气相色谱一质谱联用(GC-MS)法测定丁二烯中阻聚剂对叔丁基邻苯二酚(TBC)含量,并与分光光度法和液相色谱法进行了比较.结果表明,用甲苯作为TBc的溶剂,其在被测组分的出峰区域不会形成干扰;采用选择离子模式检测可提高灵敏度.TBC质量分数为1×10-6～50×10-6时,外标法测定TBC含量的线性回归系数为0.999 5,加标回收率为98.60%～102.73%,相对偏差为2.42%～3.87%;GC-MS法与分光光度法、液相色谱法测得丁二烯中TBC含量相近,但GC-MS法更简便和快捷.     

气相色谱-质谱联用法直接测定痕量十二烷基吗啉的方法研究

针对目前钾肥生产中反浮选药剂测定难度大,建立了一种气相色谱-质谱联用法直接测定痕量十二烷基吗啉的方法。样品溶解后经正己烷3次萃取待测,仪器条件：色谱柱TG-5MS,长度为30 m,内径为1.9 μm,膜厚度为0.25 μm;质谱参数：EI源,离子源温度为240 ℃,毛细管温度为250 ℃,进样量为1 μL,流速为1 mL/min,气相色谱分流比为40:1,色谱柱柱温选择程序升温。该方法标准工作曲线线性较好,精密度、回收率均满足分析的要求,相对标准偏差≤2%,方法的检测限为0.15 μg/mL,定量限为0.5 μg/mL。     

GC-MS测定环己烷氧化液中有机酸和酯的含量

采用气相色谱-质谱联用法(GC-MS)测定环己烷氧化液中的有机酸和有机酯的含量。在GC-MS分析条件下环己烷氧化液直接进样,通过毛细管柱DB-1701,60 m×0.15 mm×0.25μm分离,由电子轰击源选择离子监测模式下进行检测。结果表明:有机酸和有机酯的标准曲线相关系数大于0.98,相对标准偏差均小于7.0%,回收率为94.9%～98.6%。     

气相色谱-质谱联用法测定儿童产品中残留的甲酰胺

采用甲醇作萃取溶剂,超声萃取样品中残留的甲酰胺,选用DB-VRX色谱柱进行目标物分离,质谱定量检测。建立了气相色谱-质谱（GC-MS）联用法快速测定儿童产品中残留的甲酰胺分析方法。考察了萃取方法、萃取溶剂、极性色谱柱对甲酰胺分离检测的影响。结果表明,在1~30 mg/kg内,线性关系良好（R2〉0.999 5）,重现性良好。在1~10 mg/kg甲酰胺添加水平内,平均回收率为86.7%~93.2%,相对标准偏差为4.4%~6.4%。甲酰胺的方法检出限为1 mg/kg。该方法快速简捷,易于操作,适用于进出口儿童产品的甲酰胺残留量的日常检测工作。     

气相色谱-质谱与嗅觉测量法联用分析橙油中致香物质

采用气相色谱-质谱与嗅觉测量法(gas chromatography-mass spectrometry/olfactometry,GC-MS/O)联用的分析方法,对橙油的致香物质进行了分析与鉴别。GC-MS检测到35种挥发性物质,其中相对质量分数较高的化合物为柠檬烯(80.79%)、芳樟醇(3.85%)、癸醛(2.90%)、β-月桂烯(1.94%)、α-蒎烯(0.82%)、辛醛(0.71%)等。而GC-O分析到的具有香气的化合物为α-蒎烯、辛醛、柠檬烯、芳樟醇、α-松油醇、癸醛、肉豆蔻醛、(E,E)-2,4-癸二烯醛及一种具有花香、甜橘香的未知物质。采用强度法与稀释法相结合鉴别了橙油中的关键致香物质,结果表明,α-松油醇和未知物质具有最大的香气强度和稀释因子(FD因子),即二者对橙油整体香气贡献最大。采用GC-MS/O联用技术可以有效筛选出精油中的香味活性物质,而强度法与稀释法结合又可快速、准确、全面地分析样品中关键致香物质。     

Separation of stigmasta-3,5-diene, squalene lsomers, and wax esters from olive oils by single high-performance liquid chromatography run

To ascertain the authenticity of olive oils, the European Community Regulation requires the stigmasta-3,5-diene and wax ester contents to be determined. The official methods are time-consuming and not suitable for many daily analyses, as quality-control laboratories need. A method is presented here that allows single high-performance liquid chromatography separation of stigmasta-3,5-diene and wax esters, as well as of the squalene isomers, which give further information on the oil’s authenticity. For stigmasta-3,5-diene, the comparison with results obtained with the official method is good. Also for wax esters, the agreement was good, even if they were compared with results obtained from a quicker method as reliable as the official one. The possibility of separating the squalene isomers also at the same time makes the proposed method more advantageous. On the whole, the method, which is suggested for routine and quick screening but not for the exact evaluation of the analyte contents, seems to be a convenient choice for ascertaining on a daily basis the samples’ legal compliance (i.e., whether the analyte content is or is not below the legal value).     

固相萃取-气相色谱-质谱法同时测定化妆品中多环芳烃和邻苯二甲酸酯类物质

建立了固相萃取(SPE)-GC-MS法同时测定化妆品中的16种多环芳烃(PAHs)和17种邻苯二甲酸酯类(PAEs)的分析方法。样品经乙腈超声萃取后,经PSA/Slica玻璃柱净化,以Agilent Select PAH色谱柱分离,气相色谱-质谱法选择离子(SIM)监测测定。16种PAHs和17种PAEs在0.5~200μg/L范围内线性良好,相关系数均大于0.99;PAHs方法检出限为0.6~1.0μg/kg,方法定量限为1.9~3.3μg/kg,阴性样品3个添加水平的平均回收率为86.4%~112.2%;PAEs方法检出限为0.4~2.3μg/kg,方法定量限为1.5~7.6μg/kg,阴性样品3个添加水平的平均回收率为82.2%~114.1%;相对标准偏差均小于10%(n=6)。     

溶剂型胶粘剂中多环芳烃的气相色谱-质谱法检测

建立了溶剂型胶粘剂中16种PAHs(多环芳烃)含量的GC-MS(气相色谱-质谱)检测方法。分别优化了样品的萃取溶剂、净化方式和浓缩过程。研究结果表明:样品经过前处理后,可采用SIM(选择离子扫描)模式和内标法对PAHs进行定量分析;该检测方法的线性相关系数均大于0.999,检出限为0.001~0.020 mg/kg,用加标回收率法确定了该检测方法的精密度为1.54%~8.91%(n=7),16种物质的回收率为83.13%~104.32%;该检测方法具有准确、高效之特点,适用于胶粘剂中PAHs含量的定量检测。     

Analysis of the volatile fraction from sunflower oil extracted under pressure

This study concerns the analysis of volatile components that may contribute to the formation of the flavor of the oil extracted from sunflower seeds. The compounds were trapped on a charcoal cartridge, then desorbed and analyzed by gas chromatography/mass spectrometry. The principal compounds were terpenes (about 225 mg/L) consisting of α-pinene (80%), limonene (5%), sabinene (3.3%), β-pinene (1.8%), 1,2,6,6-tetramethyl-1,3-cyclohexadiene (1.5%), and camphene (1.2%). There were also a small amount of hexanal (1.3%) and traces (<1%) of unidentified compounds, which probably correspond to other terpenic hydrocarbons and to terpenic alcohols and/or aldehydes.     

Fast quantitative analysis of soybean oil in olive oil by high-temperature capillary gas chromatography

Analysis of glycerides has always been of great interest, especially to the food industry. Several methods have been developed, and attempts to improve analytical conditions are prevalent. Among these methods, high-temperature capillary gas chromatography has received particular consideration because it rapidly provides a glyceride profile. In this paper, we discuss a method to identify and quantitate mixtures of olive and soybean oils with the intention of verifying the latter as an adulterant of olive oils. The contamination of olive oil with soybean oil was detected by the presence of the triglyceride trilinolein, which does not exist in pure olive oil, although it is abundant in soybean oil. A calibration curve was constructed with several levels of contamination, and the lowest amount of detectable soybean oil was determined to be 4%.     

Analysis of epoxidized soybean oil by gas chromatography

A fast and cost-effective procedure to quantitate epoxidized soybean oil by means of an external standard method is reported. This procedure is applicable to commercial epoxidized oils, polymer additive packages and polymers—polyvinyl chloride (PVC)—containing epoxidized oils. The epoxidized soybean oil is converted into fatty acid methyl esters with tetramethylammonium hydroxide, and analyzed by capillary gas chromatography with flame-ionization detection. In PVC samples, the epoxidized soybean oil was extracted with toluene and followed by derivatization prior to analysis. The methyl esters of monoepoxyoctadecanoic, diepoxyoctadecanoic and triepoxyoctadecanoic acid were separated with a short capillary column.     

Identification and estimation of tocotrienols in the annatto lipid fraction by gas chromatography-mass spectrometry

The lipid fraction of annatto (Bixa orellana L.) seeds was extracted with a Soxhlet apparatus with n-hexane and isolated by thin-layer chromatography. The fatty-soluble antioxidant fraction contained only tocotrienols, mainly δ-tocotrienol, but no tocopherols. The presence of tocotrienols was confirmed by gas chromatography-mass spectrometry. The quantities of δ-tocotrienol were 140–147 mg/100 g dry seeds and 5.2–5.5% wt/wt of lipid extract, determined by gas chromatography and high-performance liquid chromatography, respectively. Currently no vegetable species seems to contain comparable concentrations of δ-tocotrienol.     

气相色谱法分析重质油中的饱和烃加环烷烃馏分

重质油用经典柱分离得到的饱和烃加环烷烃组分，可用SE-30石英毛细管柱，在300℃的汽化室温度下，以3℃／min的升温速率分离并进行定性和定量分析。方法简便快速，具有较高的精密度和准确度，适合于生产控制分析。     

Evaluation of nonpolar methyl esters by column and gas chromatography for the assessment of used frying olive oils

The measurement of unaltered methyl esters separated from polar methyl esters by column chromatog-raphy was used to evaluate the alteration of an olive oil that had been used 15 times to fry potatoes. Unaltered methyl ester (the nonpolar fraction) decreased significantly (94.9 ± 0.8%vs 98.2 + 0.5%; p < 0.05), while the polar fraction increased significantly (4.0 ± 0.7%vs 2.1 ± 0.7%; p < 0.05) after 15 fryings. The unrecoverable fraction also increased. In order to avoid column contamination the gas Chromatographic analysis was only done on the nonpolar fractions. Linoleic and oleic acids showed a tendency to decrease while saturated fatty acid tended to increase. The unsaturated/saturated fatty acids ratio decreased from an initial value of 7.05 to 6.40 in the last frying. Quantitative gas Chromatographic analysis using both the percentage fatty acid composition and the relative amount of unaltered methyl esters showed a significant oleic acid decrease after 15 fryings (75.8 ± 0.6vs 78.9 ± 0.2 mg/100 mg oil; p < 0.05). To whom correspondence should be addressed     

应用色-质联用技术分析1,2-二氯乙烷中的微量杂质

应用毛细管气相色谱法及色-质联用技术对1,2-二氯乙烷(1,2-EDC)中的微量杂质进行了定性鉴定,为优化聚氯乙烯生产工艺提供了依据。     

Determination of vernolic acid content in the oil ofEuphorbia lagascae by gas and supercritical fluid chromatography

Determination of the content of vernolic acid (12,13-epoxy-9c-octadecenoic) in the oil ofEuphorbia lagascae has been performed by gas chromatography of the fatty acid methyl ester derivatives of the triacylglycerols in the oil and by supercritical fluid chromatography (SFC) of the raw oil and the fatty acid derivatives of the oil. The content of vernolic acid was found to be 55 wt%. The three methods were compared, and SFC analysis of the fatty acid derivatives was found to be the most accurate method.