Quantitation of volatile compounds in heated trilinolein by static headspace-capillary gas chromatography/infrared spectroscopy-mass spectrometry

Static headspace and capillary gas chromatography/infrared spectroscopy-mass spectrometry were used to collect, separate, detect and quantitate the oxidative and thermal decomposition products in heated trilinolein. Trilinolein without added antioxidants was heated in a deep-fat fryer at 190°C for 12 h each day for a total of 24 h until the amount of polymeric material in the oil exceeded 20%. The concentration of the volatile compounds in trilinolein, as well as thep-anisidine values and polymer content, increased with an increase in heating time. After 24 h of heating, the concentrations of the major volatile compounds (>10 ppm) had increased as follows: pentane (33.4–398.7 ppm), pentanal (11.7–73.5 ppm), 1-pentanol (5.2–46.7 ppm), hexanal (67.6–346.1 ppm), (E)-2-hexenal (12.9–87.6 ppm), (E)-2-heptenal (309.6–894.1 ppm), 1-octen-3-ol (35.2–150.2 ppm), formic acid (0–18.7 ppm), hexanoic acid (0–83.8 ppm), heptanal (2.5–29.5 ppm), 2-pentylfuran (29.2–146.9 ppm), (E)-2-octenal (26.4–347.2 ppm), (E)-2-octenal (26.4–347.2 ppm), (E)-2-nonenal (31.6–163.2 ppm), (E,Z)-2,4-decadienal (15.0–320 ppm) and (E,E)-2,4-decadienal (43.1–1137.5 ppm).     

Volatile compounds in heated oleic acid-esterified propoxylated glycerol

Static headspace and capillary gas chromatography, in combination with infrared and mass spectrometry, were used to collect, separate, identify, and quantitate the oxidative and thermal decomposition products in two heated model compound triacylglycerols, oleic acid-esterified propoxylated glycerol (EPG-08 oleate) and triolein. The EPG-08 oleate and triolein were each heated in a deep-fat fryer at 192±8°C for 12 h each day until the oil contained ≥20% polymeric material. Most of the volatile compounds identified in heated triolein and EPG-08 oleate were associated with the oxidative and thermal decomposition of oleates, such as short-chain alkanes, aldehydes, and alcohols. The major volatile compounds (concentration >20 ppm) in heated EPG-08 oleate and triolein were heptane, octane, heptanal, octanal, trans-2-decenal, nonanal, and trans-2-undecenal. However, a few minor volatile compounds, not previously found in heated fats and oils, were identified in the heated EPG-08 oleate samples. These compounds included 1,2-propanediol, 1-hydroxy-2-propanone (hydroxyacetone), 1-acetoxy-2-propanone (acetoxyacetone), 2-ethyl-4-methyl-1,3-dioxolane, 2,2,4-trimethyl-1,3-dioxolane, 2-heptyl-4-methyl-1,3-dioxolane, and 4-methyl-2-octyl-1,3-dioxolane. Alkyl-substituted dioxolanes have been found in heated methyl linoleate.     

自动顶空气相色谱法快速测定饮用水中多种挥发性卤代烃

为建立快速测定饮用水中多种挥发性卤代烃的测定方法,采用DB-624毛细管色谱柱,自动顶空进样测定水中8种挥发性卤代烃,并对平衡时间、平衡温度进行研究和优化。用建立的方法对人工合成水样进行试验,每隔10min即可完成一个样品的测定。试验结果表明,水中8种挥发性卤代烃的平均加标回收率为90.5%～108.2%,相对标准偏差为1.82%～5.39%,最低检出限为0.10～0.50μg/L,对宁波市的二次供水样品的分析中有4种卤代烃检出。本研究所建立的方法简便、快速,在测定生活饮用水中多种挥发性卤代烃时具有较好的精密度与准确度。     

毛细管气相色谱法同时测定水中的7种挥发性卤代烃

本文采用毛细管气相色谱法进行同时测定饮用水中7种挥发性卤代烃的研究。实验表明,该方法前处理简单,测定方便,具有较好的灵敏度、准确度和精密度,结果令人满意。样品的加标回收率在90％～110％,相对标准偏差小于5％。     

顶空气相色谱法测定药品包装中挥发性有机物

利用顶空技术,结合毛细管气相色谱法同时测定了药品包装袋中的8种挥发性有机物,方法具有分离效果好、操作简单、精密度高、检出限低等优点,可以作为药品包装袋中挥发性有机物的检测方法。     

多方位视角提高化妆品生产企业质量与监管水平

一方面通过分析我国化妆品行业现状提出化妆品行业存在政出多头、准人门槛低、生产企业多并且检测方法缺失等问题。另一方面针对化妆品行业的问题,从全过程监管、多方力量联动提高检测能力、建立安全风险监测体系、安全评估体系以及企业自律等多方面多角度出发,通过各方面有机的联合,充分整合生产企业所在地的资源,提高化妆品行业的整体水平。     

顶空气-质联用法测定离子液体富集的空气中的苯系物

基于室温离子液体无蒸气压、离子强度高且稳定、优良溶解性等特点,实验中采用室温离子液体［bmim］［PF₆］作为吸收液,气相色谱-质谱联用分析测定离子液体富集的苯系物,建立了顶空进样-气相色谱-质谱方法测定苯、甲苯、间二甲苯、邻二甲苯、苯乙烯的最佳分析条件。结果表明离子液体有可能作为空气中苯系物的富集材料。     

Odor significance of undesirable degradation compounds in heated triolein and trilinolein

To better understand production of undesirable or negative odors such as fruity, plastic, and waxy that are characteristic of higher oleic acid-containing oils, model heated oil systems of triolein and trilinolein were studied. Identification of the odor significance of volatile compounds produced by fractionated and nonfractionated triolein and trilinolein was done by purge and trap-gas chromatography-ion trap mass spectrometry-olfactometry. The predominant odors of the triolein heated 1, 3, and 6 h at 190°C were fruity and plastic, with other negative odors of acrid and grassy. Some of the volatile compounds that produced negative odors in heated triolein, in order of increasing concentration, were hexanal (grassy), octanal (fruity), (E)-2-decenal (plastic), nonanal (fruity), and (E)-2-undecenal (plastic). Some of the negative odor compounds in trilinolein heated for 1, 3 and 6 h, in order of increasing concentration, included (E)-2-nonenal (plastic), pentanal (grassy), and hexanal (grassy). However, the amount of volatile compounds produced and the intensity levels of the odors were lower in trilinolein than in triolein. Formation of many of the volatiles was explained after identification of the volatile precursors, including epoxy, keto, and dimer oxidation products that were produced during heating. Presented at the American Oil Chemists’ Society 90th Annual Meeting & Expo, Orlando, FL, May 9–12, 1999.     

不同温度下天然橡胶中挥发性有机化合物的释放

通过静态顶空与气相色谱-质谱联用的方法,探讨了不同温度（80 ℃和130 ℃）和不同硫化温度（130,140,150 ℃）对两种天然橡胶（SVR 3 L和SPR 10#）中挥发性有机化合物（VOCs）的影响。结果表明,130 ℃下,两种天然橡胶中的主要VOCs均能挥发并被检出,SVR 3 L中的VOCs主要是乙醇和乙酸;SPR 10#中除乙醇和乙酸外,主要为醛类物质。硫化温度对两种天然橡胶中VOCs总量的影响不大,说明硫化过程中的高温高压条件可使天然橡胶中的VOCs挥发,硫化胶中的VOCs主要来源于硫化促进剂的热分解产物。     

用顶空气相色谱法测试瓶级聚酯切片中的乙醛含量

论述了瓶级聚酯切片生产过程中,采用顶空气相色谱法测试切片中乙醛含量的称样量、样品处理、颗粒度、顶空热平衡时间、热平衡温度、标定及其他顶空测量参数的优化。     

GC-MS测定饮用水中挥发性有机物

建立了吹扫捕集与气相色谱/质谱(GC-MS)联用测定饮用水中13种挥发性有机物的测定方法.该方法的加标回收率在90%～110%,相对标准偏差小于5.0%,灵敏度高,准确度好,已成功地用于饮用水中挥发性有机污染物的测定,且结果令人满意.     

Static headspace gas chromatographic analyses to determine oxidation of fish muscle lipids during thermal processing

Oxidation in fish during thermal processing was studied by determining volatile production with a static headspace gas chromatographic system. Different processing temperatures and periods were evaluated to simulate conditions of fish industrial treatments. The major volatiles formed included acetaldehyde, propanal, heptane, 2-ethylfuran, pentanal, and hexanal. Changes in volatile composition were studied for different processing times and temperatures. The method for volatile analyses to determine oxidation in fish muscle was tested by correlation with peroxide value, conjugated diene, and thiobarbituric acid indices. Significant single and multivariate regressions were found between the time of thermal treatment and volatiles produced, showing that the amount of 2-ethylfuran was the best predictor of oxidative stability in fish.     

顶空-气相色谱法同时测定塑料食品包装袋中11种有机溶剂残留量

采用顶空-气相色谱法对食品塑料包装材料中可能残留的溶剂丙酮、乙醇、乙酸乙酯、丁酮、异丙醇、正丁醇、甲苯、二甲苯等进行了分析。方法采用HP-FFAP色谱柱分离,氢火焰离子化检测器FID检测,11种溶剂能够完全分离,线性较好,样品加标回收率苯系物介于74%～78%,其他溶剂介于86%～95%,最低检出限可达0.002mg/m2。测定了10种不同材质的塑料包装材料中的溶剂残留量和苯系物残留量,方法简便、快速、重现性好,完全能满足塑料包装材料中溶剂残留量的分析。     

Effect of blanching on volatile compounds and structural aspects of Cordyceps militaris dried by microwave-assisted pulse-spouted bed freeze-drying (MPSFD)

Effect of low temperature blanching at 50°C (for 15, 30, and 60?min) and high temperature blanching at 100°C (30, 60, and 120?s) on volatile compounds and structural properties of Cordyceps militaris dried by microwave-assisted pulse-spouted bed freeze-drying were investigated. A total of 83 volatile compounds were identified. Blanching at 100°C remarkably decreased the ketones and alcohols while contributed to the formation of alkanes. The absence at 993?cm^?1 and the appearance near 1548?cm^?1 in samples blanched at 100°C were observed, indicating blanching at high temperature would cause the loss of polysaccharides and the degradation of proteins. Principal component analysis and cluster analysis suggested that volatile compounds in untreated samples and those blanched at 50°C for 15?min were similar. In general, blanching at 50°C for 15?min is recommended regarding the retention of flavor components and structural properties of dried C. militaris.     

顶空固相微萃取-气相色谱法测定水中四氢呋喃的研究

以顶空固相微萃取为样品的前处理手段,结合气相色谱,以氢焰离子化检测器测定水样中的四氢呋喃.通过对萃取头类型、萃取时间和温度、解吸温度和时间等影响萃取效率的因素的研究,获得了优化的试验条件.在优化条件下,方法的线性较好,样品的加标回收率为97.5%-106.7%,相对标准偏差为3.2%-4.9%,检出限可以达到0.10μ...     

食用植物油中溶剂残留量的顶空气相色谱标准加入法测定研究

对食用植物油中的溶剂残留测定方法进行了改进。用样品作基体配制标准溶液,采用顶空进样气相色谱测定,标准加入法定量。方法线性范围在ofμg／g-200μg/g,检测低限1．0μg/g,在1-μg／g-200μg／g浓度范围内,标准添加回收率为87．8％-107．4％．相对标准偏差6．06％-11．8％。本方法采用标准加入法进行定量,样品和标准的基体一致,避免了基体的影响,该法简便、快速,适合食用植物油中的溶剂残留的分析。     

原位盐脱水顶空气相色谱测煤焦化废水的苯酚含量

采用原位盐脱水-顶空气相色谱技术对煤焦化废水中的苯酚含量进行了测定。废水经脱水盐吸收后其所含苯酚自然由水相进入气相,用顶空-气相色谱仪进行检测。结果表明:无水氯化钙脱水效果较好;5.2 g无水氯化钙在90℃平衡12 h可完全吸收500μL样品中的水分;顶空分析的平衡温度为150℃、时间为30 min时可达到苯酚的全气化;该方法平行检测的相对标准偏差为4.0%,最低检测极限为3.25μg,回收率在91.1%~104%。方法操作简单、准确性高、无试剂干扰,适于检测煤焦化废水中的苯酚含量。     

Separation and identification of phenolic acids and related compounds by gas chromatography and fourier transform infrared spectroscopy

Phenolic acids and related compounds were separated by gas chromatography using three separate columns. One of these columns was coupled to a Fourier transform infrared spectrometer. The trimethylsilyl derivatives could be separated and identified by comparing the relative retention times of the three different columns. However, where there was overlap, the accompanying infrared data clearly distinguished between the questionable derivatives, thus enabling characterization of all derivatives.The use of trade, firm, or corporation names in this article is for the information and convenience of the reader. Such use does not constitute an official endorsement or approval by the U.S. Department of Agriculture or the Forest Service of any product or service to the exclusion of others that may be suitable.     

顶空液相微萃取-气相色谱法测定指甲油中的苯类物质

本实验采用顶空液相微萃取法,正辛醇作为萃取溶剂,样品在30℃水浴条件下搅拌顶空萃取25 min。待测物结合气相色谱分析方法,采用程序升温和分流进样,用氢火焰离子化检测器建立了测定指甲油中苯类物质的新方法。各种目标物的线性相关系数在0.983 3～0.993 4之间,加标回收率在95.88%～97.70%之间。该方法稳定可靠,分析结果良好。     

气相色谱-质谱/质谱法测定美白化妆品中5种酚类物质

建立了同时测定化妆品中苯酚、氢醌、间苯二酚、4-丁基间苯二酚和苯乙基间苯二酚5种酚类物质的气相色谱-质谱/质谱(GC-MS/MS)检测方法。样品在0.03 mol/L磷酸二氢钾溶液中超声提取,经HLB固相萃取小柱净化后,过0.22μm有机滤膜,采用GC-MS/MS分析。选择SH-Rtx-1701(30 m×0.25 mm×0.25μm)色谱柱分离,采用EI离子源电离、MRM采集模式,外标法定量。结果表明,5种酚类物质在10 min内完成色谱分离,检出限和定量限分别为1.5～3.0μg/L和5.0～10.0μg/L,5种酚类物质在5～200μg/L范围线性良好,相关系数均大于0.9994,以阴性样品为基质,在不同添加水平下,5种酚类物质的平均回收率为73.5%～111.8%,相对标准偏差(RSD,n=6)在1.0%～11.1%之间。本方法分析时间短,灵敏度好,准确性高、操作方便、净化效果好,可同时测定化妆品中5种酚类物质。