高效液相色谱法分离制备鱼油中的EPA和DHA

采用反相高效液相色谱技术,以μ－ＢｏｎｄａｐａｋＣ１８作固定相,ＣＨ３ＯＨ／ＴＨＦ／Ｈ２Ｏ作流动相,对鱼同中的二十碳五烯酸（ＥＰＡ）和二十二碳六烯酸（ＤＨＡ）进行了分离纯化,制备溶液经减压蒸馏,乙酸乙酯萃取后所得ＥＰＡ和ＤＨＡ质量分数可分别达到９８％和８６％以上。     

甲鱼油脂肪酸组成的研究

用热提取方法抽取出甲鱼油，用ＫＯＨ－ＣＨ３ＯＨ酯交换法甲酯化处理，以色谱／质谱方法测定脂肪酸的组成。共鉴定出２１种脂肪酸，其中以棕榈酸、棕榈油酸、硬脂酸、油酸、亚油酸、二十碳五烯酸（ＥＰＡ）、二十二碳五烯酸（ＤＨＡ）为主     

HPLC/ECD测定人血小板中5-羟色胺浓度

用ＨＰＬＣ／ＥＣＤ法测定血小板５－ＨＴ,运用 ＷａｔｅｒｓμＢｏｎｄａｐａｋ Ｃ柱,３,４二羟基苄胺（ＤＨ－ＢＡ）作内标,以 ０.０７ ｍｏｌ／Ｌ乙酸钠缓冲液＋乙腈为流动相（２０＋１）,每１Ｌ缓冲液含 ０．０５ ｍｏｌ／Ｌ柠檬酸、２．５ ｍｍｏｌ／Ｌ庚烷磺酸钠、０．１ｍｍｏｌ／Ｌ Ｎａ_２ＥＤＴＡ,流速０．８ ｍＬ／ｍｉｎ。ＤＨＢＡ和 ５－ＨＴ的保留时间分别为５．４和１１．５ ｍｉｎ,线性范围为０．０２５～１ｍｇ／Ｌ（ｒ＝ ０．９９９７）。５－ＨＴ日内 ＲＳＤ低于１．８７％,日间ＲＳＤ低于８．５４％,方法回收率为１００．４％±２．３％。提示本方法快速简便,灵敏准确,适用于临床基础研究。     

气相色谱—原子发射光谱法测定水中微量路易氏剂的水解产物

本文用气相色谱－微波诱导等离子体原子发射光谱检测器（ＧＣ－ＭＩＰ－ＡＥＤ）对水中微量路易氏剂的水解产物的测定方法进行了研究，在酸性条件下，路易氏剂的水解产物与２，３－二巯基丙醇（ＢＡＬ）迅速反应形成挥发性的衍生物，在４８０．１９２，１８１．３７９和１８９．０４２ｎｍ波长下分别检测了衍生物的氯，硫，砷元素的发射信号，最小检测量为０．１μｇ／Ｌ。回收率为８７．２％～９７．４％。     

快速气相色谱法测定蔬菜中甲胺磷和水胺硫磷残留量

蔬菜中甲胺磷和水胺磷残余经氯仿萃取后，用气相色谱－火焰光度检测器（ＧＣ－ＦＰＤ）直接测定，色谱柱为ＤＢ－１７大口径石英毛细管柱，采用气相色谱－离子阱质谱系统检测样品中的甲胺磷和水胺硫磷，在三个不同含量水平的收率试验中，本法的回收率为９３．６％－１０４．１％，最低检测限可达０．０６μｇ／ｇ     

固相微萃取-气相色谱联用技术分析饮用水中的氯仿

利用顶空固相微萃取与气相色谱联用技术（ＨＳ－ＳＰＭＥ－ＧＣ）对饮用水中的氯仿进行了分析,并探讨了ＳＰＭＥ萃取头、吸附和热解吸时间对测定结果的影响;聚丙烯酸酯（ＰＡ）萃取头对水中的氯仿有较佳的富集效果,方法具有较好的重现性（ＲＳＤ为５．２３％,ｎ＝８）,线性范围为５～１００μｇ／Ｌ,检出限为３．４５μｇ／Ｌ。     

毛细管气相色谱／原子吸收联用及大蒜油中痕量硒化学形态分析的研究

本文提出并建立了毛细管气相色谱／原子吸收联用（ＣＧＣ／ＡＡＳ）装置，并在此装置上建立了（ＣＨ３）２Ｓｅ、（ＣＨ３）２Ｓｅ２的分析方法。本方法的最小检测量分别为０．３ｎｇ和０．０４ｎｇ。回收率分别为９７％～１０５％和９３％～１１０％，已用于大蒜油的实际样品分析，取得了满意的结果。     

脱氧核糖核酸变性和损伤的吸附伏安法研究

本文用汞电极（ＨＭＤＥ）二次导数阴极吸附伏安（ＳＤ－ＡｄＣＳＶ）和碳电极（ＧＣＥ、ＣＰＥ）导数循环伏安（ＦＤ－ＣＶ）法研究了核酸受热、紫外线、超声波和丝裂霉素Ｃ（ＭＭＣ）作用下的变性作用。在０．１ｍｏｌ／Ｌ（Ｋ２ＨＰＯ４＋ＫＨ２ＰＯ４）－０．１ｍｏｌ．Ｌ ＮａＣｌ（ｐＨ７．０）底液中，吸附的单股（ｓｓ－）和双螺旋（ｄｓ－）ＤＮＡ分别在ＨＭＤＥ上得到特征还原峰Ｐ３和Ｐ２，和在碳电极上得到氧化峰Ａ。物     

二巯基丙醇衍生气相色谱—微波诱导等离子体—原子发射光谱测定…

用气相色谱－微波等离子体－原子发射光谱检测器（ＧＣ－ＭＩＰ－ＡＥＳ）测定水中微量无机砷，在酸性条件下，Ａｓ（Ⅲ与２，３－二巯基丙醇（ＢＡＬ）的反应生成挥发性的环状二硫胂衍生物，被甲苯萃取，在１８１．３７９ｎｍ和１８９．０４１ｎｍ处ＧＣ－ＭＩＰ－ＡＥＳ分别检测衍生物中硫砷的发射信号，检出限为１５ｐｇ（以砷计）加标回收率９６．３５－１０６．０３％，变异系数〈４．５％。     

高密度聚乙烯／低密度聚乙烯／乙烯－醋酸乙烯共聚物共混体系的结晶行为

通过ＤＳＣ和ＷＡＸＤ研究了高密度聚乙烯／低密度聚乙烯／乙烯－醋酸乙烯共聚物（ＨＤＰＥ／ＬＤＰＥ／ＥＶＡ）三元共混体系的热行为和结晶性能。发现当ＨＤＰＥ含量小于４０％时，ＥＶＡ对ＬＤＰＥ起稀释剂作用，促进ＨＤＰＥ、ＬＤＰＥ的晶相分离，使ＨＤＰＥ、ＬＤＰＥ单独结晶．当ＨＤＰＥ含量高于４０％时，ＬＤＰＥ片晶进入ＨＤＰＥ晶相。形成与ＬＤＰＥ在片晶水平上的共晶。     

毛细管气相色谱法测定深海鱼油中的EPA和DHA含量

用氢氧化钾－甲醇酯化法将深海鱼油中的脂肪酸快速、有效地转化成脂肪酸甲酯,然后进行毛细管气相色谱法测定,以二十二碳饱和脂肪酸甲酯为内标物,建立了5,8,11,14,17－二十碳五烯酸（EPA）和4,7,10,13,16,19－二十二碳六烯酸（DHA）的定量分析方法,并用于实际样品分析。该方法对EPA和DHA定量分析的相对标准偏差分别为4．6％和5．0％,回收率分别为99．7％和99．4％。     

Isolation and structural analysis of the cyclic fatty acid monomers formed from eicosapentaenoic and docosahexaenoic acids during fish oil deodorization

Long-chain polyunsaturated fatty acids (LC-PUFAs) present in fish oils are thermolabile molecules. Among the degradation reactions encountered, thermal cyclization occurs during refining or other heat treatments. Numerous studies have been carried out in the past to quantify and determine the structures of cyclic fatty acid monomers (CFAMs) formed from oleic, linoleic and linolenic acids in heated vegetable oils. Recently, much attention have been given to LC-PUFAs due to their potential health benefits. However, data on quantification of CFAMs formed from these fatty acids, such as eicosapentaenoic acid (EPA, cis-5, cis-8, cis-11, cis-14, cis-17 20:5) and docosahexaenoic acid (DHA, cis-4, cis-7, cis-10, cis-13, cis-16, cis-19 22:6), the two main LC-PUFAs in fish oils, are scarce. In the present study, structural analyses of CFAMs formed from EPA and DHA during the deodorization of fish oil are presented. Fish oil sample was deodorized at 250 degrees C for 3 h under a pressure of 1.5 mbar in a laboratory deodorizer. The CFAMs formed during heat treatment of fish oil were isolated by a combination of saponification, esterification, urea fractionations and column chromatography. Structural analyses of C20- and C22-CFAMs were achieved by gas-chromatography electronic-ionization mass-spectrometry (GC-EI-MS) of their 4,4-dimethyloxazoline (DMOX) derivatives. We identified seven out of 13 possible structures of hydrogenated CFAMs formed from EPA, and nine out of 16 possible structures of CFAM formed from DHA. Major CFAMs from both EPA and DHA were cyclohexyl isomers. All possible cyclohexyl isomers were found but only nine out of 18 of the cyclopentyl isomers were present in concentration sufficient for identification. Chemical mechanisms involved in the formation of polyunsaturated LC-PUFAs have been investigated. The results have shown that general principle involved in the cyclization of LC-PUFAs is same as that for the thermal cyclization of oleic, linoleic and alpha-linolenic acids.     

Quantification of eicosapentaenoic and docosahexaenoic acid geometrical isomers formed during fish oil deodorization by gas-liquid chromatography

Long-chain polyunsaturated fatty acids (LC-PUFAs) of the n-3 series and especially eicosapentaenoic and docosahexaenoic acids (EPA and DHA, respectively) have important biological properties. The main dietary sources of LC-PUFAs are fish and fish oil. Geometrical isomerization is one of the main reactions happening during the thermal treatment of polyunsaturated fatty acids. Refined fish oils are used to supplement food products in LC-PUFAs and the quality of these nutritional ingredients have to be controlled. In the present study, a suitable method for the quantification of EPA and DHA geometrical isomers in fish oils by gas-liquid chromatography (GC) is presented. A highly polar capillary column (CP-Sil 88, 100 m) operating under optimal conditions was used. Method selectivity was studied by GC-mass spectrometry. The performance characteristics of the quantification method were studied using samples of fish oil deodorized at 220 degrees C for 3 h. The linearity of the method was assessed by analyzing composite samples obtained by mixing fish oil deodorized at 220 degrees C with semi-refined fish oil (control). Precision was evaluated by analyzing the same samples in triplicate. Results showed that the validated method is suitable to quantify low amounts of geometrical (trans) isomers of EPA and DHA in refined fish oils. The limits of quantification of the EPA and DHA geometrical isomers are 0.16 and 0.56 g/100 g of fish oil, for EPA and DHA, respectively. Commercially available LC-PUFA oil samples were evaluated by using the validated method. The results show that the oils analyzed contain low amounts (<1% of total fatty acids) of geometrical isomers of EPA and DHA.     

In Vitro and In Vivo Digestibility of Soybean,Fish, and Microalgal Oils,and Their Influences on Fatty Acid Distribution in Tissue Lipid of Mice

The digestion rates of microalgal (docosahexaenoic acid, DHA, 56.8%; palmitic acid, 22.4%), fish (DHA, 10.8%; eicosapentaenoic acid, EPA, 16.2%), and soybean oils (oleic, 21.7%; linoleic acid, 54.6%) were compared by coupling the in vitro multi-step and in vivo apparent digestion models using mice. The in vitro digestion rate estimated based on the released free fatty acids content was remarkably higher in soybean and fish oils than in microalgal oil in 30 min; however, microalgal and fish oils had similar digestion rates at longer digestion. The in vivo digestibility of microalgal oil (91.49%) was lower than those of soybean (96.50%) and fish oils (96.99%). Among the constituent fatty acids of the diet oils, docosapentaenoic acid (DPA) exhibited the highest digestibility, followed by EPA, DHA, palmitoleic, oleic, palmitic, and stearic acid, demonstrating increased digestibility with reduced chain length and increased unsaturation degree of fatty acid. The diet oils affected the deposition of fatty acids in mouse tissues, and DHA concentrations were high in epididymal fat, liver, and brain of mice fed microalgal oil. In the present study, microalgal oil showed lower in vitro and in vivo digestibility, despite adequate DHA incorporation into major mouse organs, such as the brain and liver.     

Optimization of Fatty Acid Determination in Selected Fish and Microalgal Oils

The use of ten fatty acid methyl ester reference standards coupled with a detailed quantification method was shown to significantly optimize the fatty acid determination of selected fish and microalgal oils when compared to methods that use only one reference standard (C19:0 or C23:0) as a relative response factor. When using the mixture of ten reference standards after transesterifying oils with NaOH/BF₃, determination of total fatty acids, eicosapentaenoic acid and docosahexaenoic acid improved by an average of 7.3, 11.5 and 8.4%, respectively. Furthermore, improvements of 13.9, 18.9 and 6.8% of total fatty acids, EPA and DHA, respectively, were obtained when using the mixture of reference standards for fatty acid determination after directly extracting and transesterifying oil contained in microalgal cells with a mixture of methanol, HCl and chloroform. Fatty acid methyl ester standards dissolved in isooctane showed <5% variability throughout 130 days of stability testing when stored at ?20 °C. The optimized method can be used for improving the quantification of fatty acids in both oils (fish and microalgal oils) and dry microalgal cells.     

气相色谱全分析海水和淡水养殖南美白对虾组织中脂肪酸组成与含量

采用超声提取-毛细管气相色谱法分析测定了海水养殖和淡水养殖的南美白对虾的肌肉和肝胰腺(中肠腺)中脂肪酸的组成与含量,以用于对虾繁殖与营养的研究。采用Folch 液超声提取对虾组织中的脂质,脂质经氢氧化钾-三氟化硼法甲酯化后上机分析。采用BPX70(60 m×0.25 mm i.d.)石英毛细管柱分离,火焰离子化检测器检测。以线性程序升温等当碳长度(ECLT)值结合标准品对照的方法对17种脂肪酸定性,用面积归一化法定量。结果表明,两种对虾的脂肪酸组成均以不饱和脂肪酸为主,而且不饱和多烯酸的含量明显高于不饱和单烯酸。两种对虾的肌肉脂肪酸中高度不饱和脂肪酸,如二十碳五烯酸(EPA)与二十二碳六烯酸(DHA)的总含量均较高,达20%以上;肝胰腺中EPA和DHA的总含量较低,为11%～17%。淡水虾中n-6族不饱和脂肪酸含量比海水虾高,海水虾中n-3族与n-6族脂肪酸含量之比值比淡水虾高。     

碱催化法衍生化气相色谱/质谱法分析青海湖裸鲤鱼油中的脂肪酸

用碱催化法将青海湖裸鲤鱼油甲酯化,以气相色谱/质谱法分析鱼油中的脂肪酸。青海湖裸鲤可食用部分中鱼油含量为25.13%。从鱼油中共鉴定出47种脂肪酸,包括直链、单支链、多支链饱和脂肪酸,单不饱和、多不饱和脂肪酸,环丙烷基、呋喃基脂肪酸等。不饱和脂肪酸含量为73.6%,其中多不饱和脂肪酸含量为25.4%,以C18∶2(4.9%),C18∶3(3.1%),C20∶4(1.3%),C20∶5(二十碳五烯酸（EPA）, 9.4%)和C22∶6(二十二碳六烯酸（DHA）, 6.7%)为主。单不饱和脂肪酸含量为48.2%,主要由C16∶1(20.3%),C18∶1(25.9%)构成。饱和脂肪酸含量为25.7%,主要有C14∶0(3.4%),C16∶0 (19.4%)和C18∶0(1.1%)。青海湖裸鲤鱼油中还存在不常见的环丙烷基和呋喃基脂肪酸及多种奇数碳链和支链脂肪酸。因此,青海湖裸鲤是功能性脂肪酸的重要膳食来源。     

河豚鱼脂肪酸的气相色谱—质谱分析

采用ＧＣ／ＭＳ技术对２种河豚鱼（黄鳍、红鳍）脂肪提取物中的脂肪酸进行定性定量分析，共鉴别出２４种脂肪酸。多不饱和脂肪酸尤其是二十二碳六烯酸（ＤＨＡ）的含量很高，在黄猪中相对含量达３２．３２％，在红鳍中达２４．１１％。检出了在其它海产品中较少发现的１５－二十四烯酸（神经酸），是人体生长发育不可缺少的一种脂肪酸。对鱼肉脂肪提取方法及不同极性毛细管柱分离情况进行了讨论。     

Plasma free fatty acid profiling in a fish oil human intervention study using ultra-performance liquid chromatography/electrospray ionization tandem mass spectrometry

A rapid method was developed for the simultaneous profiling of 29 free fatty acids in plasma using ultra-performance liquid chromatography/electrospray ionization tandem mass spectrometry (UPLC/ESI-MS/MS). Barium acetate was used as the cationization agent in the positive ion mode for sensitive multiple reaction monitoring (MRM) experiments. The cis- and trans-C18:1 and -C18:2 isomers were baseline-separated using two tandem reversed-phase C18 UPLC columns, while identification of two pairs of positional isomers of C18:3 and C20:3 required isomer-specific product ions, as the analytes were not chromatographically resolved. The assay linearity was greater than three orders of magnitude and correlation coefficients were >0.99; the limits of detections were typically less than 0.2 microM. The method was successfully applied to plasma free fatty acid profiling of samples from volunteers who participated in a randomized crossover study involving the administration of either placebo or fish oil capsules. The results clearly indicate the ability to measure the time profiles of the n-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in plasma for the volunteers given fish oil capsules while the concentrations of the other free fatty acids and the total free fatty acid concentration in plasma remained virtually constant.