Optimized Method to Analyze Rose Plant Volatile Organic Compounds by HS-SPME-GC-FID/MSD

A method involving Headspace solid-phase microextraction (HS-SPME) fiber combined with gas chromatography (GC) coupled with flame ionization detection (FID) and gas chromatography with mass spectrometry (GC-MS) was developed and optimized to investigate volatile organic compounds (VOCs) from different tissues (flowers, leaves, stems, rhizosphere and whole plants) of Floribunda and Hybrid Tea roses (intact and cut). Three-phase fiber 50/30 μm divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) was used. Two types of chambers (Tedlar bag and glass jar) were evaluated for collection of VOCs and glass jar was selected. Absorbed compounds on the fiber were completely desorbed in the GC injector port at three desorption times (5, 10 and 15 min), and 5 min at 250?C was used. The maximum extraction efficiency for flowers tissues (equilibrium absorption) was achieved 2 h after fiber exposure in the headspace for intact and cut Floribunda and Hybrid Tea flowers. Under the optimized HS-SPME and GC-FID/MS conditions, 1h extraction time was chosen for intact and cut Floribunda and Hybrid Tea leaves and stems. The results demonstrated that 5 cm depth was selected for root and soil part (rhizosphere) for both rose cultivars, and 6 h and 12 h extraction time of VOCs from rhizosphere was achieved for Floribunda and Hybrid Tea, respectively. One hour was chosen for VOCs released from whole rose plants for both cultivars. In this study, the VOC profiles of two rose cultivars were characterized by the optimized HS-SPME-GC method. The different tissues of rose plants gave wide range of the VOCs;also the chromatograms of different cultivars were quite different and the specific VOC pattern of rose types depends on the species. Results from this study demonstrate the feasibility of this method for identifying VOCs from two rose cultivars and the potential use of this method for physiological studies on rose plants or on other floriculture plants.

顶空固相微萃取-气相色谱法测定海水中丁基锡

建立了一种利用顶空固相微萃取-气相色谱法（HS-SPME-GC）检测海水中3种丁基锡化合物（一丁基锡、二丁基锡、三丁基锡）的方法.在优化实验条件时,选取缓冲溶液的pH值、缓冲溶液体积、平衡时间、萃取时间、萃取温度等5个因素进行L16（45）正交试验设计.结果表明,一丁基锡、二丁基锡、三丁基锡的线性范围分别为0.05~1 000.00,0.02~1 000.00,0.02~1 000.00μg.L-1;检出限分别为50,8,8ng.L-1;加标2μg.L-1时,回收率分别为106%,89%,91%.将该方法用于涉及中国4大海域的深圳、上海、连云港、青岛、大连、烟台等6个沿海城市近海海水样品的测定,除了青岛海滨水样外,其他5个城市海水样中均检测出了不同质量浓度的有机锡.

优化GC检测欧李酒香气成分的萃取条件

香气物质的组成表征果酒的特色,利用响应面法优化顶空固相微萃取(HS-SPME)欧李果酒中香气物质的条件,使气相色谱法检测香气物质的结果更精确。本文采用HS-SPME结合GC-FID检测欧李发酵酒中的香气物质,在单因素实验的基础上,以加盐量、萃取温度、萃取时间为影响因素,出峰面积为响应值,运用Box-Benhnken中心组合实验设计原理进行响应面分析,优化了HS-SPME的萃取条件。结果表明,HS-SPME萃取欧李发酵酒中香气成分的适宜条件为:加盐量0.226g/mL、萃取温度29℃、萃取时间36min。该条件下萃取,结合GC-FID测得欧李发酵酒中32种香气成分,对其中10种进行了定性和定量分析,含量较高的有:异戊醇110.734mg/L、己酸乙酯11.568mg/L、异丁醇8.7725mg/L、苯乙醇47.178mg/L、乙酸异戊酯15.655mg/L、丙醇1.7032mg/L。

顶空固相微萃取-气要色谱-氢火焰离子化法检测啤酒中的酒花香气成分

来自酒花的微量香气成分会影响啤酒的感官评价和质量。为评价酒花香气对啤酒的影响，本文采用顶空固相微萃取（Hs—SPME）对啤酒前处理后，使用常见且低成本维护的气相色谱一氢火焰离子化法fGC—FID）进行定性定量。以2一壬醇为内标，测定出里那醇、乙酸香茅酯、仪一萜品醇、B一香茅醇、香叶醇5种酒花香气成分。此法的精密度为4．69％～13．41％，回收率为74．95％～106．09％，检出限为0．005～O．028μg·L-1。通过此法进行啤酒检测，结果显示：啤酒中这5种酒花香气含量均〈10μg·L-1，大部分在0．10～5．00μg·L-1之间。研究表明：该法测定准确可靠；与已有方法如顶空固相微萃取一气质联用法（HS—SPME—GC—Ms）相比，该法的仪器常见，维护成本更低，更适合啤酒厂推广使用。

柚子皮生物炭质用于河水中苯系物的固相微萃取

苯、甲苯、乙苯和二甲苯(邻二甲苯、间二甲苯、对二甲苯)组成的苯系物(BTEX)是炼油厂和石化厂等工业园区普遍制造和排放的碳氢化合物,具有一定的毒性和致癌作用,对生态环境和人类健康造成极大威胁。研究以低成本、绿色且富含木质素和含氧官能团的柚子皮作为植物原料,在有限氧条件下采用程序升温热解法制备了柚子皮生物炭质吸附剂,通过N吸附-脱附等温线和孔径分布图对不同热解温度下制备的柚子皮生物炭质吸附剂的孔隙结构进行了考察。结果表明:在1 000℃热解温度下制得的柚子皮生物炭质具有更高的比表面积(749.9 m^(2)/g)、更大的孔体积(0.42 cm^(3)/g)、更集中的孔径分布(2~3 nm)。将吸附剂通过溶胶-凝胶法(sol-gel)涂覆在铁丝上制成固相微萃取纤维,与气相色谱-火焰离子化检测器(GC-FID)相结合,对影响萃取和分离BTEX的条件进行优化,建立了用于BTEX检测的高灵敏度分析方法。方法具有检出限低(0.004~0.032μg/L)、线性范围宽(1~100μg/L)、线性关系好、萃取效率高(约为商品化涂层聚二甲基硅氧烷(7μm)的2.9~18.3倍)等优势。此外,应用该方法已成功在河水样本中检测出了乙基苯(4.80μg/L),邻二甲苯(3.00μg/L)和对二甲苯、间二甲苯(2.46μg/L)。最后将该方法应用于河水样本的加标试验中,得到了满意的回收率(75.7%~117.6%)。实验结果表明所建立的分析方法可实现对环境水样(河水)中BTEX的低成本、高灵敏度检测。

Optimization of Headspace Solid-Phase Microextraction Conditions for the Identification of Volatiles Compounds from the Whole Fruit of Lemon, Lime, Mandarin and Orange

An optimum method has been developed for extracting volatile organic compounds (VOCs) which contribute to the aroma of different species of citrus fruit (orange, lemon, lime, and mandarin). Headspace solid phase microextraction (HS-SPME) combined with gas chromatography (GC) coupled with flame ionization detection (FID) is used as a very simple, efficient and non-destructive extraction method. A three phase 50/30 μm PDV/DVB/CAR fibre was used for the extraction process. The optimal sealing time for volatiles reaching equilibrium from whole fruit in the headspace of the chamber was 20, 16, 8 and 16 hours for lemon, lime, mandarin, and orange respectively. Optimum fibre exposure times for whole fruit were 2, 4, 2 and 2 hours for lemon, lime, mandarin, and orange respectively. Three chamber volumes (500, 1000 and 2000 ml) were evaluated for the collection of VOCs with the 500 ml chamber being selected. The 500ml chamber produced the highest quality peak areas and quantity of extracted volatiles. As a result of fruit respiration, the percentage of oxygen (O2) of all citrus fruit species in 500 ml chamber decreased from 21.8% to 18.8% in the 20 hours sealing time, while carbon dioxide (CO2) contents increased to 2.9% also in the 20 hours sealing time. The results of this study showed the feasibility of this technique for identifying VOCs from four of the citrus fruit species and its potential as a routine method for physiological studies on citrus fruit or on other fruit species.

Safety of Lebanese Bottled Waters: VOCs Analysis and Migration Studies

Despite the worldwide increase in the consumption of PET-bottled mineral waters compared to tap waters encouraged by its microbiological and chemical safety for public health, contaminants could migrate from the plastic packaging into the water and induce adverse effects on human health. Volatile organic compounds (VOCs), including benzene, toluene, ethylbenzene, ortho, meta, and para-xylenes (BTEX), styrene, chlorobenzene and benzaldehyde are among the potential contaminants of bottled waters. This study aimed to assess Lebanese PET-bottled waters, in respect of VOCs contents, with comparison to polycarbonate-bottled and tap waters. Both HS-SPME-GC/FID and SPE-GC/FID were optimized and validated for VOCs determination in the waters, and their performances were compared. The HS-SPME-GC/FID was valid (Afnor NF T 90-210 (May 2009)) for all the studied molecules with limits of quantifications (LOQ) far lower the maximum contaminants levels (MCLs) set by both US-EPA and WHO. SPE-GC/FID was valid only for ethylbenzene, m/p-xylenes, o-xylene, and styrene, with poorer LOQs. HS-SPME-GC/FID was used therefore for VOCs monitoring in studied water samples showing the safety of the Lebanese bottled-water. The effects of bottles storage conditions (time, and exposure to sunlight) on VOCs migration were also studied.