纯水-顶空毛细柱气相色谱法分析废气中的甲醇

纯水吸收气体中的甲醇,采用顶空毛细柱气相色谱法进行分析。重点对顶空毛细柱气相色谱法测定甲醇的分析条件进行试验探讨。实验结果表明,采用纯水-顶空毛细柱气相色谱法测定甲醇方法简便,标准曲线具有良好的线性回归,方法的灵敏度、精密度、准确度较高,符合现代仪器的发展趋势。     

Volatile Emissions of Ammonium Nitrate under Flowing Conditions

Ammonium nitrate (AN) is an ionic solid commonly used as a fertilizer and in commercial blasting applications. Frequently, AN is mixed with a fuel and used in improvised explosives devices (IEDs). To characterize the low‐volatility components emanating from AN, a sample of AN was sealed inside a stainless steel chamber while a laminar flow of air swept the headspace vapor components into a water impinger or cold‐trap for pre‐concentration and subsequent analysis by ion chromatography (IC). Both collection methods were found to be 100 % efficient for collecting nitric acid vapor, whereas the collection efficiency for ammonia was dependent upon the collection method and, for the water impinging method, additionally upon the vapor concentration, humidity and flow rate. Cold‐trapping efficiency for ammonia was 4 %±2 % across all parameters studied. Water impinging was more efficient (20–70 %), but the efficiency varied according to each of the aforementioned variables. The characteristics of an AN vapor generated from a solid sample were found to vary as the sample approached equilibrium inside the chamber. Initially, large quantities of ammonia were observed, but as a steady state was achieved within the laminar flow and a dynamic equilibrium established, the ratio of ammonia to nitric acid in the effluent vapor dropped, although never becoming equimolar. The ratio was strongly dependent upon humidity.     

顶空气相色谱法测定伊索拉啶中的乙醇残留量

本文用顶空气相色谱法测定了伊索拉啶中的乙醇含量，用ＧＤＸ－１０２色谱柱分离，ＦＩＤ检测。在０．１－２．０ｍｇ／ｍｌ范围内线性良好，样品和标准品的相对标准偏关分别为３．６％和４．５％。     

顶空气相色谱-质谱联用法测定蜡烛中香茅油的含量

本文采用顶空进样气相色谱-质谱联用法测定蜡烛中香茅油的含量。选用硅油为母液,优化了色谱条件、顶空加热温度、平衡时间等实验条件,并进行了线性、精密度和回收率实验。方法简单、快速,定性定量准确可靠。     

顶空气相色谱法测定聚乙烯中环已烷含量

建立了用顶空气相色谱法测定聚乙烯中挥发性烃类的分析方法。讨论了平衡时间、平衡温度、气—固体积比等因素对测定结果的影响。方法的相对标准偏差(BSD%)为1.0%~4.0%。方法快速、准确、重复性高。     

顶空-气质联用法分析炭黑原料油储罐油汽成分

分析了炭黑生产企业原料油储罐上空的油汽成分以及相对含量。两个不同型号炭黑原料油放入顶空瓶后密封,温度110℃平衡30 min,挥发出的油蒸汽进入气相色谱-质谱仪进行分析检测。使用Trace Finder质谱软件结合NIST11谱库检索,确定油汽含有几十种有机化合物,如苯、联苯、萘、苊、芴、菲等轻质芳烃。同时利用峰面积归一化法计算出各组分的相对含量,结果显示:两种炭黑原料油成分含量无明显差别,主要成分均为甲苯(1#13.67%,2#9.43%)、二甲苯(1#9.11%,2#6.39%)、二氢茚(1#19.10%,2#13.62%)、萘(1#22.31%,2#32.47%)。了解储油罐油汽成分及相对百分含量,不仅能够明确其环境危害,而且可以为炭黑企业依据GB50160-2008《石油化工设计防火规范》制定自身安全操作规范提供参数。     

顶空气相色谱法测定醇醚产品中微量环氧乙烷

建立了测定醇醚产品中微量环氧乙烷的顶空气相色谱法.样品经80℃、30min静态顶空后,采用气相色谱-氢火焰离子化检测器进行检测,外标法定量.该方法加标回收率在88.3％~104.7％,相对标准偏差在0.66％~3.94％.应用此法杂质干扰少,对醇醚产品中微量环氧乙烷在0.4~25mg／kg线性关系良好(7>0.998)...     

Determination of Critical Micelle Concentration of Surfactants by Headspace Gas Chromatography

This paper presents a new method for the determination of the critical micelle concentration (CMC) of surfactants in water at elevated temperatures using headspace gas chromatography (HS‐GC). A volatile compound (e.g., toluene) was spiked into the studied solution. At a given temperature, the concentration of volatile species in the vapor phase (measured by HS‐GC) is proportional to the surfactant concentration in the liquid phase in a closed vial. This tendency will change after the solution is saturated with surfactant. By plotting the GC signal of the vapor species vs the concentration of the surfactant concentration in the solution, a breakpoint, i.e., corresponding to the CMC of the surfactant. The present method has good precision (RSD < 10%) and good accuracy. It is also very simple and can be used as an automated method for determining the critical micelle concentration of surfactants at the temperature of interest.     

气相色谱顶空法测定天然水中苯系物

文章采用顶空-自动、毛细管柱进样对天然水中苯系物(包括苯及其同系物甲苯、乙苯、间二甲苯、对二甲苯和邻二甲苯)进行了测定,通过气相色谱法分析水中苯系物,结果表明用顶空法气相色谱分析测定天然水中苯系物方法是可行的,实用性强,精密度准确度高,检出限在O.001～0.002 mg/mL,均能达到国家标准方法的测定要求.     

车间空气中挥发性醇类有机物的顶空气相色谱测定方法研究

应用顶空气相色谱法测定车间空气中乙醇、异丁醇、异戊醇等微量极性有机物,分析方法的线性范围乙醇在0 01～0 16mg/ml浓度范围内,异丁醇、异戊醇在0 001～0 016mg/ml浓度范围内,标准曲线的相关系数r=0 9999。最低检出限分别为,乙醇2 3×10-8mg/ml,异丁醇2 5×10-8mg/ml,异戊醇3 6×10-8mg/ml。方法精密度变异系数分别为,乙醇1 95%,异丁醇7 66%,异戊醇6 90%。加标平均回收率分别为,乙醇94 11%,异丁醇88 37%,异戊醇91 54%。该法干扰少,灵敏度高,分离效能好,准确度高,适合于车间空气中挥发性醇类物质的检测。     

顶空气相色谱法测定辣椒红色素中二氯甲烷的残留量

采用HP-1熔融硅毛细管色谱柱和Ni63电子捕获检测器(ECD),建立了顶空进样气相色谱法测定辣椒红色素中二氯甲烷残留量的分析方法,对气相色谱的测定条件进行了优化.本方法的线性范围为0.020～1.0μg/mL,最低检测限为0.01μg/mL,样品的添加回收率为105.00%～114.75%,相对标准偏差(RSD)为0.9%～3.8%.应用于实际样品的分析,结果满意.     

轮胎气味的研究

对轮胎气味的判定进行试验研究。首先采用人工气味评价方法对轮胎中气味进行闻测,然后采用顶空气相色谱/质谱法对可疑的气味物质进行测定,筛选出气味物质。该分析结果可以为通过调整轮胎配方或工艺改进轮胎气味效果提供依据。     

顶空气相色谱法测定烟用胶粘剂中的有机挥发物

采用顶空气相色谱法对烟用胶粘剂中的有机挥发物（甲醇、丙酮、乙酸甲酯、叔丁醇、乙酸乙烯酯、乙酸乙酯）进行分析,讨论了气相色谱柱的升温方式、顶空平衡温度、平衡时间、胶粘剂加入量对分析结果的影响,从而获得优化的检测工艺参数。该检测方法对上述六种有机挥发物的线性范围分别为甲醇0～400礸,丙酮0～40礸,乙酸甲酯0～92礸,叔丁醇0～32,乙酸乙烯酯,0～75礸,乙酸乙酯0～45礸;测定结果的相对标准偏差为0.6%～2.7%;样品的回收率为90.8%～104.2%;可用于烟用胶粘剂中有机挥发物的分析,方法简便、快速、重现性好。     

Effects of Deuterium Oxide on the Oxidative Stability and Change of Headspace Volatiles of Corn Oil

Effects of deuterium oxide and deuterium oxide-free water on the oxidative stability and formation of headspace volatiles were determined for corn oils to evaluate the role of moisture as an active influential factors during lipid oxidation. Mixtures of corn oil and water with different ratios of deuterium oxide were prepared, and the mixtures were stored at 60 °C for 2 days. Headspace oxygen contents, conjugated dienoic acid (CDA) values, and p-anisidine values (p-AV) were analyzed as a measure of oxidative stability, and headspace volatiles were analyzed by solid phase microextraction and a gas chromatography mass selective detector to determine the involvement of deuterium in volatiles. Deuterium oxide accelerated the rate of lipid oxidation in corn oil compared to oils with deuterium-free water based on the results of headspace oxygen content, CDA, p-AV, and total volatile content. Fragmented mass to charge ratios (m/z) of 73.1/72.1 for d ₁-pentane/pentane and 57.0/56.0 for d ₁-2-propenal/2-propenal from samples containing deuterium oxide were significantly higher than those from deuterium oxide-free water, implying that moisture participated to form volatiles in corn oil oxidation under air-tight condition. Deuterium oxide appeared to accelerate the rate of lipid oxidation in corn oils and participated to form volatiles from oils during oxidation.     

Effect of dissolved inorganic salts on the isothermal vapor–liquid equilibrium of the propionic acid–water mixture

Propionic acid–water is one of the minimum boiling point azeotropic binary mixtures. Alteration of the vapor–liquid equilibrium (VLE) by addition of inorganic salts is of interest, since it allows bypassing the azeotropic point due to salt-in and salt-out effects. The effect of NaCl, NH₄Cl, CaCl₂, and AlCl₃ at salt concentrations of 1 m and the effect of NaCl molality (0.5–3 m) on the VLE of the binary propionic acid–water mixture has been experimentally investigated at 60 °C using the headspace gas chromatography (HSGC) technique. The alteration in the VLE of the system was salt type and salt concentration dependent. Salting out of the propionic acid was observed when salts were added and was most obvious in the case of AlCl₃ salt. The salt effect parameter, determined from the Furter's equation was a function of the liquid concentration.     

动态顶空进样–气质联用法分析PA10T树脂的可挥发性组分

采用动态顶空进样-气质联用法对半芳香族尼龙树脂PA10T进行了分析。结果表明:在加工温度条件下,PA10T树脂中主要挥发组分有15种,主要为醛类、烃类、腈类、芳环类物质和少量含氮环状物质。该方法快速,准确,可以作为PA10T树脂品质控制用检测方法。     

Hydroperoxide as a Prooxidant in the Oxidative Stability of Soybean Oil

Fifteen milliliters of soybean oil having peroxide value (PV) of 0, 2, 4, 6, 8, or 10 meq/kg oil in a 35 mL serum bottle was sealed air-tight with a Teflon rubber septum and aluminum cap and was stored in a forced-air oven at 50 °C. The oxidative stability of soybean oil was evaluated daily for six days by measuring the headspace oxygen content and volatile compounds in the headspace of a sample bottle by gas chromatography. As the initial PV of the oil increased from 0 to 2, 4, 6, 8 and 10, the headspace oxygen decreased and the volatile compounds increased at p < 0.05. Hydroperoxide accelerated the oxidation of soybean oil. The correlation coefficient (R ²) between the headspace oxygen and the volatile compounds was 0.95. The increase of tertiary butyl hydroquinone (TBHQ) from 0 to 50 ppm for the oil of PV 4 or 8 had a significant effect on the oxidative stability at p < 0.05. The increase from 50 to 100 ppm for the oil of PV 4 or 8 did not significantly increase the stability at p > 0.05. The oxidative stability of PV 8 meq/kg and 50 ppm TBHQ was better than the control with PV 0 and 0 ppm TBHQ at p < 0.05. TBHQ was an effective antioxidant to improve the oxidative stability of soybean oil.     

顶空气相色谱法测定污水中挥发醛

采用顶空气相色谱法测定化工厂排放污水中低沸点易挥发的甲醛、乙醛、丙醛含量。方法快速,灵敏度高,准确性好,适应生产控制要求。     

Profiles of volatile compounds in milk containing fish oil analyzed by HS‐SPME‐GC/MS

Long‐chain polyunsaturated fatty acids (LC‐PUFA) have various positive biological effects. Fish oil represents a major source of LC‐PUFA; therefore it is extensively used to enrich food products as, for example, infant formulae, dairy products and fruit juices. However, in the presence of oxygen and metals, LC‐PUFA readily degrade, producing off‐flavors and decreasing the nutritional value of the product. The deterioration of sensory properties (taste and odor) can be easily perceived by the consumer, due to the formation of volatile compounds that are formed by decomposition of lipid hydroperoxides, also known as primary oxidation products. In this study, we used the headspace solid‐phase microextraction‐gas chromatography/mass spectrometry technique (HS‐SPME‐GC/MS) to characterize and quantify volatile compounds in a food matrix supplemented with fish oil. We demonstrated that the HS‐SPME‐GC/MS method is a valuable tool to monitor lipid oxidation at early stages. We identified t‐2‐hexenal and c‐4‐heptenal as possible oxidation markers during the storage of milk enriched with 5% of cod oil.     

标准加入法测聚醚多元醇中环氧丙烷单体的含量

考察了静态顶空进样外标法和标准加入法测定聚醚中环氧丙烷残留量的可行性,确定了以待测聚醚为基质,定量添加环氧丙烷的标准加入法进行定量的分析方法。色谱使用岛津GC-2014,配备rtx-1毛细管色谱柱(30 m×0.25 mm×0.25?m)和氢火焰离子化检测器(FID)。微量单体测定结果的相对标准偏差10%,检测限低至3×10-6,该方法具有适应性强,准确简便等优点。