微波蒸馏-顶空固相微萃取-气质联用检测鱼体中土霉味化合物

采用微波蒸馏-顶空固相微萃取-气质联用检测鱼体中常见的两种土霉味化合物,即2-甲基异茨醇(2-MIB)和土腥素(Geosmin)。研究并优化了微波蒸馏萃取过程的关键参数(微波蒸馏时间、载气流量),结果表明微波蒸馏6min、载气流70mL/min为土霉味化合物微波蒸馏萃取的最佳条件。在此优化的条件下,土霉味化合物能够充分地从鱼体中蒸馏出来,再采用顶空固相微萃取的方法使馏分中的土霉味化合物吸附于纤维涂层上,将其在250℃高温下解吸,并用GC-MS分析。基于此测定方法,鱼肉中2-甲基异茨醇和土腥素的检测限均达到

冷却包装猪肉辐照异味气体成分研究

【目的】研究冷却真空包装辐照猪肉异味气体主要成分和寻找异味源,为探明异味产生机理及去除方法奠定理论基础。【方法】用真空系统液氮冷却装置收集冷却真空包装猪肉辐照异味气体,用气相色谱质谱联用仪测定收集气体成分,确定异味气体成分并推测异味源。【结果】冷却真空包装猪肉辐照异味气体主要成分是二甲硫、二甲二硫、甲硫醇、乙酸甲硫醇酯;辐照异味气体来源于肉中半胱氨酸、蛋氨酸和维生素B1。异味气体量随辐照剂量增加而增加(0～3kGy),随辐照后冷藏时间延长而下降,与包装类型密切相关(P<0.05)。【结论】冷却真空包装猪肉

重庆市主城区长江和嘉陵江水中有机污染物对斑马鱼胚胎仔鱼的毒性研究

目的以重庆市主城区大溪沟(嘉陵江)和寸滩(长江)两个点为代表,研究2004~2005年度重庆市水源水中有机污染物的组成和对斑马鱼胚胎仔鱼的毒性。方法固相萃取法萃取水中有机污染物,GC/MS检测有机污染物的种类;将萃取的有机污染物溶于DMSO中,并用斑马鱼胚胎仔鱼实验研究水中有机污染物对斑马鱼胚胎孵化率和仔鱼畸形率的影响。结果四个水样中均可检出有机污染物,污染物的种类以酞酸酯类和多环芳烃类为主;污染物可导致斑马鱼胚胎孵化率降低及仔鱼畸形率增加,其毒性呈现出时间和剂量依赖性;同一采样点中,枯水期水样毒性大于丰

武汉大莲花湖异味化合物日变化及其相关因子分析

大莲花湖位于武汉市汉阳区莲花湖公园内,是以休闲娱乐为主的景观水体,面积约为64000m2。近年来,该湖不断出现蓝藻水华,每到夏季湖区臭不可闻,损害了莲花湖旅游度假景区的景观生态价值和经济收入。本文对大莲花湖藻类及其异味化合物与环境因子的日变化进行了研究。结果表明,夏季大莲花湖藻类以微囊藻占优势。据GC-MS鉴定,该湖水中存在着2-MIB、-βCyclocitral和-βIonone等3种异味化合物。水中溶解性2-MIB、-βCyclocitral和-βIonone日最高浓度分别可达69.1ng/L3、2.

南方某地产妇和婴儿体内多氯联苯蓄积水平的调查

目的了解我国南方某多氯联苯(PCBs)高暴露地区的产妇及其婴儿体内PCBs的蓄积水平。方法采集在当地某医院中符合条件的50对母婴对的母乳和脐带血,用GC-MS法进行PCBs含量的测定。结果母乳中13种PCBs总浓度的最大值为237 ng/g类脂,几何均数为138 ng/g类脂。脐带血中13种PCBs总浓度的最大值为102 ng/g类脂,几何均数为56.9 ng/g类脂。结论该地区妇女和婴儿体内普遍检测出较高水平的PCBs

南方某地妇女儿童血液中多氯联苯蓄积水平调查

目的了解我国南方某多氯联苯(PCBs)高暴露地区的妇女、儿童体内PCBs的蓄积水平。方法采集当地某小学中符合条件的50对母子的血液,用GC-MS法进行PCBs含量的测定。结果儿童血液中所测的13种PCBs的浓度最大值为505 ng/g类脂,几何均数为192 ng/g类脂;母亲血液中所测的13种PCBs的总浓度的最大值为461 ng/g类脂,几何均数为176 ng/g类脂;儿童和母亲血液中PCBs含量的相关系数为0.74。结论该地区妇女和儿童血液中检测出较高水平的PCBs,儿童和母亲血液中PCBs含量呈现较

污水中8种雌激素化合物的定量测定

采用固相萃取-气相色谱-质谱法(GC-MS)测定污水中辛酚(OP)、壬酚(NP)、双酚A(BPA)、己烯雌酚(DES)、雌酮(E1)、17β-雌二醇(E2)、17α-乙炔雌二醇(EE2)和雌三醇(E3)8种具有雌激素活性的化合物。被测组分的加标回收率为(65.4±4.0)%～(110.0±4.5)%,检出限为1.0～7.5ng/L(相对标准偏差为5.2%～15.6%)。经检测,武汉某城市污水处理厂进水中的目标化合物(除EE2外)浓度为6.5～8954.9ng/L;除EE2和E3外,出水中的浓度为3.2～2

顶空固相微萃取-气相色谱-质谱测定水中异味化合物

采用顶空固相微萃取-气相色谱/质谱联用测定了水中常见的3种异味化合物,即2-甲基异茨醇、土腥素和β-柠檬醛。研究并讨论了纤维头的类型、盐的种类和浓度、温度、萃取时间、搅拌和解吸时间等因素对异味化合物萃取量的影响。结果表明:在水样中加入30%(W/V)的NaCl溶液,采用65μmPDMS/DVB纤维头,在搅拌的条件下,于60℃顶空萃取40min为异味化合物固相微萃取的最佳条件。在优化的条件下,使异味化合物吸附于纤维涂层后,将其在250℃高温下解吸,再用GC-MS分析。土腥素、β-柠檬醛、2-甲基异茨醇的检出

复合垂直流构建湿地系统净化水体中的痕量有机物

在稳定运行三年的复合垂直流构建湿地中试系统中进行了水体中痕量有机物的净化研究。进水为东湖茶港附近的湖水。水流方式为下行流 -上行流 ,进水方式采用间歇式 ,间隔为 8h ,水力负荷为 80 0mm3/(mm2 ·d)。采用C18反相SPE柱富集萃取中试系统的进出水及自来水 ,然后对其进行GC/MS分析 ,结果表明 ,东湖水主要为石油烃污染 ,酞酸酯类污染严重 ,自来水中亦存在痕量有机物的污染。复合垂直流构建湿地中试系统的出水比进水中痕量有机物的种类及数量均有所减少 ,说明这种系统有助于水体中痕量有机物的去

Finnigan MAT95高分辨率气相色谱质谱联用仪离子源恒温控制系统故障的分析与排除

介绍了德国Ｆｉｎｎｉｇａｎ公司生产的ＭＡＴ９５型气相和液相色谱（ＧＣ／ＭＳ）联用仪离子源加热系统故障的分析、检查和排除的方法。类似仪器故障的分析与排除具有较好的参考价值。

八角枫挥发油化学成分研究

八角枫是八角枫科八角枫属药用植物 ,分布较广。用气相色谱 /质谱 /计算机联用技术 ( GC/MS/DS)分析了水蒸气蒸馏得到的八角枫挥发油 ,鉴定出 5 9种化学成分 ,其主要成分为 :1 ,8-桉叶素 ( 43.32 5 % )、β-侧柏烯 ( 1 0 .71 3% )、丁香酚甲醚 ( 7.0 88% )、α-松油醇( 7.0 1 7% )、α-蒎烯 ( 5 .830 % )等 5种化合物。被鉴定的 5 9种成分 ,共占挥发油总量的97.0 4 %。

ANTHROPOGENIC ORGANIC CONTAMINANTS IN WATER AND SURFACE SEDIMENTS OF LARGE SHALLOW EUTROPHIC CHAOHU LAKE, CHINA

To characterize the contamination of anthropogenic organic contaminants in the aquatic environment of Chaohu Lake, China, 7 samples for both water and surface sediment were collected in the lake. Organic contaminants were extracted by solid phase extraction (SPE) and Soxhlet extraction from the water and surface sediment samples, respectively, and then analyzed by GC-MS. One hundred and twenty kinds of organic chemicals were detected in these samples including phenol, benzene series, benzaldehydes, ethanol, polycyclic aromatic hydrocarbons (PAHs), sulfur compounds, alcoholic halides, amines, ketones, esters, alkenes and alkanes. Among them, 13 kinds of chemicals were identified as priority pollutants listed by the U.S. Environmental Protection Agency (EPA), such as phthalate esters (PAEs) and PAHs. Besides, the concentrations of 19 of PAEs and PAHs including, priority pollutants identified were also determined. Bis(2-ethylhexyl)phthalate, the predominant component of the analyzed pollutants, was in the range from 72.34 ng g(-1) DW to 613.71 ng g(-1) DW, 14.80 ng L-1 to 47.05 ng L-1 in sediment and water, respectively. The results indicated that the northwest part of the lake was heavily polluted by domestic and industrial wastewater.

The synthesis of astaxanthin esters, independent of the formation of cysts, highly correlates with the synthesis of fatty acids in Haematococcus pluvialis

The compositions and contents of astaxanthin esters and fatty acids in four types of Haematococcus pluvialis cells were studied by HPLC and GC-MS. Results showed that the synthesis and accumulation of astaxanthin was independent of the formation of cysts, but was highly correlated with the synthesis and accumulation of fatty acids, though it is an well known phenomenon that the accumulation of astaxanthin is usually accompanied by the formation of cyst. The red cysts contain more than 30% of fatty acids, with 81% of the unsaturated fatty acids. Taken together, besides a resource of astaxanthin, H. pluvialis would be a good resource of valuable fatty acids.

Headspace solid-phase microextraction with novel sol-gel permethylated-beta-cyclodextrin/hydroxyl-termination silicone oil fiber for determination of polybrominated diphenyl ethers by gas chromatography-mass spectrometry in soil

A simple, sensitive, and accurate method for determination of polybrominated diphenyl ethers (PBDEs) in soil has been developed based on headspace solid-phase microextraction (HS-SPME) followed by gas chromatography-mass spectrometry (GC-MS). Permethylated-beta-cyclodextrin/hydroxyl-termination silicone oil (PM-beta-CD/OH-TSO) fiber was first prepared by sol-gel technology and employed in SPME procedure. By exploiting the superiorities of sot-gel coating technique and the advantages of the high hydrophobic doughnut-shaped cavity of PM-beta-CD, the novel fiber showed desirable operational stability and extraction ability. After optimization on extraction conditions like water addition, extraction temperature, extraction time, salts effect, and solvents addition, the method was validated in soil samples, achieving good linearity (r>0.999), precision (R.S.D. < 10%), accuracy (recovery>78%), and detection limits (S/N =3) raging from 13.0 to 78.3 pg/g. (c) 2007 Published by Elsevier B.V.

Allelopathic interactions between Potamogelon maackianus and Microcystis aeruginosa

The allelopathic interactions between Potamogeton maackianus and toxic cyanobacteria (Microcystis aeruginosa) were studied. P maackianus inhibited the growth of M. aeruginosa, both in a coexistence culture system and in exudates experimental culture system. M. aeruginosa also showed effects on the secondary metabolic biosynthesis and secreting behavior of P maackianus. The main lipophilic components of the hexane extracts and the exudates from the macrophyte were analyzed through GC-MS determination. The lipophilic components of the hexane extracts and the exudates from P. maackianus were influenced by M. aeruginosa or their released chemicals. Comparing the lipophilic constituents of the hexane extracts with those in the exudates, the results showed that weak polar compounds contained in the macrophytes can be secreted into the surrounding water. Many compounds, such as N-phenyl-2-naphthalenamine and isopropyl myristate, were detected both in the hexane extracts and the exudates. The changes of lipophilic components in the hexane extracts would be a response to the stress of toxic cyanobacteria or their released toxins. Those changes of exudates, especially the increased content of N-phenyl-2-naphthalenamine, might also be an induced defensive behavior mediated by the released toxins from M aeruginosa. The study results about reciprocal allelopathic responses between macrophytes and cyanobacteria can help in the management of eutrophic waters, and is also important information concerning strategies for recovering eutrophic waters.