Determination of Ochratoxin A in Wheat and Maize by Solid Bar Microextraction with Liquid Chromatography and Fluorescence Detection

Solid bar microextraction (SBME), followed by liquid chromatography with fluorescence detection (HPLC-FLD), for the quantification of ochratoxin A in wheat and maize was developed. Ground wheat and maize grains were extracted with acetonitrile-water-acetic acid (79:20:1, v/v/v), followed by defatting with cyclohexane, and subjected to SBME-LC-FLD analysis. SBME devices were constructed by packing 2 mg sorbent (C18) into porous polypropylene micro-tubes (2.5 cm length, 600 μm i.d., and 0.2 μm pore size). SBME devices were conditioned with methanol and placed into 5 mL stirred sample solutions for 70 min. After extraction, OTA was desorbed into 200 μL of methanol for 15 min, the solution was removed in vacuum, the residue was dissolved in 50 μL of methanol-water (1:1, v/v) and ochratoxin A content was determined by HPLC-FLD. Under optimized extraction conditions, the limit of detection of 0.9 μg·kg⁻¹ and 2.5 μg·kg⁻¹ and the precision of 3.4% and 5.0% over a concentration range of 1 to 100 μg·kg⁻¹ in wheat and maize flour, respectively, were obtained.     

Chemical composition of the essential oil and n-hexane extract of Stachys tmolea subsp. Tmolea Boiss., an endemic species of Turkey,and their mosquitocidal activity against dengue vector Aesdes aegypti

Stachys tmolea subsp. tmolea Boiss. is endemic to Turkey and is a species of the genus Stachys L. which is one of the largest genera of the family Lamiaceae with about 300 species. The aims of this study were to examine the chemical composition of the essential oil and n-hexane extract of S. tmolea subsp. tmolea as natural sources of insecticidal activity against the dengue vector, Aedes aegypti. Analysis of the essential oil by GC-FID and gas chromatography-mass spectrometry (GC-MS) systems identified hexahydrofarnesyl acetone (15%), viridiflorol (10%), hexadecanoic acid (7%) and 9-geranyl-p-cymene (6%) as major components. The volatile components of the n-hexane extract were extracted using headspace solid-phase microextraction (HS-SPME) and were analyzed using GC-MS. The principal constituents were 3,4-dimethyl decane (16%), 3-methyl-3-pentanol (15%), 2-methyl-2-pentanol (12%), 1,4-bis (1,1-dimethylethyl) benzene (12%), heptanal (10%), acetic acid (6%) and decane (4%). Bioassay of the n-hexane extract, at 5 µg/mosquito, produced 90% mortality against adult Ae. aegypti while the S. tmolea essential oil demonstrated 13% mortality. No larvicidal activity was observed both in essential oil and n-hexane extract. Further studies are needed to assess the adulticidal activity of the responsible compounds in the crude extract.     

海桐花蕾挥发油的GC-MS分析

目的:提取海桐花蕾中的挥发性成分。方法:采用固相微萃取法和水蒸气蒸馏法,并用GC-MS测定其化学成分,分别鉴定了67种和41种成分,并用归一化法测定其相对百分含量。结果:与水蒸气蒸馏法相比,固相微萃取法得到的十一烷、壬烷、α-荜澄茄油烯等的含量增加;同时提取出了水蒸气蒸馏法不能蒸馏出来的一些成分,如:α-胡椒烯、α-金合欢烯、β-月桂烯、马鞭草烯等。结论:采用固相微萃取法和水蒸汽蒸馏法,提取挥发油的时间明显缩短     

河南产结香花蕾和花的挥发性成分研究

目的:研究河南产结香花蕾和花的挥发性成分。方法:采用顶空固相微萃取和气质联用技术(HS-SPME-GC-MS),首次分析了河南产结香花蕾和花的挥发性成分。结果:从花蕾中鉴定了48种组分,从花中鉴定了45种组分。其中有19种组分二者是相同的。结论:醇类化合物大部分存在于花蕾中,而花中含有大量的酯类化合物,说明醇类化合物在结香花开放的过程中可能逐步被植物体内的酶催化形成酯类化合物。     

SPME-GC-MS分析鱼眼草花、茎叶挥发油成分

目的:对贵州产鱼眼草植物花、茎叶挥发油成分进行研究。方法:采用固相微萃取技术提取挥发油成分,用气相色谱-质谱联用技术对挥发油进行分析测定。结果:从鱼眼草花挥发油中共鉴定出34个化学成分,其中含量较高的组分分别为:大香叶烯-D(35.71%)、β-蒎烯(15.35%)、β-顺式罗勒烯(10.95%)、2,4-二异丙基-1-甲基-乙烯基环己烷(6.64%)、γ-榄香烯(3.90%)等。从鱼眼草茎叶挥发油中共鉴定出27个化学成分,其中含量较高的组分分别为邻苯二甲酸二异丁酯(28.25%)、α-红没药醇(9.18%)、β-蒎烯(8.44%)和邻苯二甲酸正丁异辛酯(6.90%)等。结论:β-蒎烯在鱼眼草不同部位挥发油中含量都较高。     

野茼蒿的挥发性成分研究

目的：研究野茼蒿的挥发性成分。方法：用固相微萃取（solid-phase microextrations,SPME）和气相色谱-质谱（gas chromatography-mass spectrometry,GC-MS）联用仪对野茼蒿的挥发性成分进行测定。结果：从中共鉴定出37种化学成分。含量最多的3种成分是月桂烯（61.609%）、牛儿烯D（6.481%）、α-葎草烯（6.293%）。结论：茼蒿主要挥发性成分为烯烃。     

HS-SPME/GC-MS法分析黑莓(萨尼)果实中挥发性成分

目的分析黑莓(萨尼)果实中的挥发性成分。方法用顶空固相微萃取和气质联用技术(HS-SPME/GC-MS),结合保留指数法并用峰面积归一化法测定相对百分含量。结果共鉴定出23种挥发性成分,相对含量占挥发性成分总峰面积的77.78%。结论主要挥发性成分为2-庚醇(27.28%)、α,α,4-三甲基苯甲醇(11.27%)、1-(1-丁炔)环戊醇(8.69%)、4-甲基-1-(1-甲基乙基)-3-环己烯-1-醇(4.94%)等。     

In vitro evaluation of the permeation through reconstructed human epidermis of essentials oils from cosmetic formulations

The permeation of essential oils through SkinEthic^® reconstructed human epidermis, (RHE), was studied in vitro to establish a convenient tool to monitor the kinetics of release of active principles from cosmetic formulations. Twelve days old human epidermis held on polycarbonate disks was revitalized by addition of growth medium and incubated at 37 °C in 5% CO₂ atmosphere for five days prior to investigation. A system of six custom designed glass Franz-type diffusion cells were used for the permeation studies at 34 °C. The diffusion kinetic for 8 selected terpenes (camphor, carvone, 1,8-cineole, linalool, menthol, α-thujone, menthone, t-anethole), chosen as analytical markers of a mixture of plant essential oils contained in a cosmetic formulation, was probed by HS/SPME–GC–MS analysis and elaborated according to Fick's first law to obtain skin permeability coefficients (P_S = 1.51, 1.47, 1.36, 0.80, 0.62, 0.40 and 0.14 × 10⁻³ cm/h, respectively). The method proved to be sensitive, simple and reproducible, and RHE represents a convenient model for safety/quality assessment of cosmetic formulations.     

HS-SPME-GC/MS法分析连花清瘟胶囊制剂原料中的挥发性成分

[目的]分析连花清瘟胶囊制剂原料中的挥发性成分。[方法]采用顶空固相微萃取法(HS-SPME)萃取连花清瘟胶囊制剂原料中的挥发性成分,通过气相色谱-质谱法(GC/MS)对其中所含挥发性成分进行分析,经NIST05质谱数据库自动检索对未知化学成分进行准确定性,并采用峰面积归一化法计算各个化学成分的相对含量。[结果]从连花清瘟胶囊制剂原料的挥发性成分中共鉴定出53种化合物,占总挥发性成分的98.30%,其中l-menthol含量最高,其相对含量为94.84%,其他含量较高的挥发性成分为patchouli alcohol(1.101%)、α-bulnesene(0.398%)、α-gurjunene(0.256%)、α-guainene(0.210%)、α-patchoulene(0.171%)和β-patchoulene(0.111%)。[结论]HS-SPME-GC/MS法可以简单、快速、准确的分析连花清瘟胶囊制剂原料中的挥发性化学成分。     

Identification of Volatile and Semi-Volatile Compounds in Polymeric Coatings Used in Metal Cans by GC-MS and SPME

Polymeric coatings are used as a protective layer to preserve food or beverage quality and protect it from corrosion and avoid a metallic taste. These types of materials can contain some chemicals that are susceptible to migrate to food and constitute a risk for consumers’ health. This study is focused on the identification of volatile and semi-volatile low molecular weight compounds present in polymeric coatings used for metal food and beverage cans. A method based on solid–liquid extraction followed by gas chromatography–mass spectrometry (GC-MS) was optimized for the semi-volatile compounds. Different solvents were tried with the aim of extracting compounds with different polarities. Furthermore, a method based on solid-phase microextraction (SPME) in headspace (HS) mode and gas chromatography coupled with mass spectrometry (HSSPME-GC-MS) was developed for the identification of potential volatile migrants in polymeric coatings. Some parameters such as extraction time, equilibrium temperature, or the type of fiber were optimized. Different compounds, including aldehydes such as octanal or nonanal, alcohols such as α-terpineol or 2-butoxyethanol, ethers, alkenes, or phthalic compounds, among others, were identified and confirmed with analytical standards both via SPME analysis as well after solvent extraction.