反相高效液相色谱法测定牙膏中的甘草次酸

采用反相高效液相色谱法测定了牙膏中的甘草次酸。在ＹＷＧ Ｃ１８（４０ｍｍｉ．ｄ．×２５０ｍｍ,１０μｍ）色谱柱上,以Ｖ（甲醇）∶Ｖ（００１ｍｏｌ／ＬＫＨ２ＰＯ４）＝８５∶１５（ｐＨ３０）的溶液为流动相,流速为１０ｍＬ／ｍｉｎ,紫外检测波长为２５４ｎｍ,室温下检测。甘草次酸用甲醇提取。甘草次酸的平均回收率为９９６１％～１０１６７％,样品测试相对标准偏差为１８５％～３１６％。方法操作简便、快速和准确。     

眼镜蛇蛇油中甘油三酸酯的成分研究

用ＡｇＮＯ３－硅胶薄层板，氯仿＋丙酮（２０＋１）为展开剂，将蛇油中甘油三酸酯分离为５个组分，并用同样的色谱固定相和石油醚－氯仿－丙酮溶剂系统进行制备性分离。用质谱法对甘油三酸酯进行分子一级水平的化学研究，确定了眼镜蛇蛇油中５个主要的甘油三酸酯成分的结构形式为：１６∶０－１８∶０－１８∶０，１６∶０－１８∶０－１８∶１，１６∶０－１８∶２－１８∶１，１８∶２－１８∶２－１８∶０，１８∶２－１８∶２－１８∶１。     

反相高效液相色谱法测定杀虫剂中吡虫啉的含量

报道了反相色谱法测定杀虫剂中吡虫啉的含量，该法采用ＹＷＧ－Ｃ１８（２５０ｍｍ×４．０ｍｍ，１０μｍ），柱，以甲醇－水（含０．１％二乙胺，ｐＨ５．０），（３５：６５，Ｖ／Ｖ，１．０ｍＬ／ｍｉｎ）为流动相，紫外检测波长为２７０ｎｍ，０．１６ＡＵＦＳ，样品可直接用甲醇超声提取。样品中吡虫啉平均回收率≥９７．４３％，相对标准偏差≤２．１％。     

对土壤及玉米植株中均三氮苯类除草剂的残留分析

土壤或玉米植株样品用Ｖ（甲醇）∶Ｖ（乙腈）＝１∶１提取,提取液用石油醚净化后,浓缩液过Ｃ１８小柱净化,最后用Ｎｏｖａ－ＰａｋＣ１８柱进行ＨＰＬＣ分析。回收率：氰草津为８２．４％～９９．８％,莠去津为８５．６％～１０２．３％,西草净为８９．１％～１０８．４％。     

牙菌斑有机酸的气相色谱-质谱分析

采用ＧＣ／ＭＳ联用技术分析了正常人牙菌斑内有机酸成分。发现了１４种有机酸,其中有８种直链饱和脂肪酸、４种直链非饱和脂肪酸、２种芳香酸。含量最多的是Ｃ１６∶０,Ｃ１８∶０,Ｃ１８∶１３种脂肪酸。其中苯乙酸、苯丙酸及十五碳酸等３种成分是第１次在牙菌斑中检测出。     

HPLC法测定中成药制剂中10-羟基-2-癸烯酸的含量

采用ＳｐｈｅｒｉｓｏｒｂＣ１８柱,以甲醇∶水∶磷酸（４５∶６５∶０．５）为流动相,以ＵＶ２１０ｎｍ为检测波长,测定中成药制剂中１０－羟基－２－癸烯酸（１０－ＨＤＡ）的含量,１０－ＨＤＡ浓度在０．００６～０．０３０ｇ／Ｌ范围内线性关系良好（ｒ＝０．９９９９,ｎ＝５）,检测限为０．２ｍｇ／Ｌ（Ｓ／Ｎ＝３∶１）。方法具有定量准确、快速及主峰和杂质分离度高等特点。     

测定玻璃体和房水中维拉帕米含量的高效液相色谱法

研究了用ＨＰＬＣ 测定兔眼玻璃体和房水中维拉帕米含量的方法。用丙咪嗪为内标， 采用Ｓｐｈｅｒｉｃａｌ Ｃ１８色谱柱分离， 以甲醇－ ０ ．０４ ｍｏｌ／Ｌ 醋酸铵－ 乙腈－ 二乙胺（ 体积比１ ∶１ ∶０ ．５ ∶０ ．０２） 为流动相， 检测波长为２７８ｎｍ 。样品用正己烷－ 异丁醇提取后进样， 分析速度快。 样品及内标的保留时间分别为４ ．６３ ｍｉｎ 及９ ．２３ ｍｉｎ ； 线性范围为２ ．５ ～１００ ｍｇ／Ｌ， 相关系数ｒ 为０ ．９９９ ７ 。方法的回收率为１００ ．３ ％ （ ｎ ＝ ５） ，ＲＳＤ 为３ ．６３％ ， 日内ＲＳＤ 为０ ．５ ％ ～３ ．６１ ％ ， 日间ＲＳＤ 为３ ．７５ ％ ～４ ．８０ ％ ， 最低检测质量浓度为０．２５ ｍｇ／ Ｌ。 应用该法测定了创伤家兔玻璃体和房水中维拉帕米浓度的变化。     

高效液相色谱法检测弹性蛋白中锁链素

用高效液相色谱技术对弹性蛋白水解液中锁链素进行了测定。单一锁链素,锁链素、酪氨酸、苯丙氨酸混合液及弹性蛋白水解液经Ｃ１８柱分离,甲醇－水（２８,Ｖ／Ｖ）洗脱,紫外检测器２８０ｎｍ检测。锁链素与酪氨酸峰面积比（ＣＡ）和峰高比（ＣＨ）分别为１．４％和３．４％,标准曲线浓度范围０．１６～０．６４ｍｇ／Ｌ时相关系数为０．９９５６。结果表明：上述色谱条件可定量测定弹性蛋白中锁链素含量,无需将锁链素与水解液中其它氨基酸加以分离,而仅需同其它２７５ｎｍ有吸收的组分区分。     

用HPLC法测定五氯硝基苯和多菌灵的复配制剂

采用ＨＰＨｙｐｅｒｓｉｌＣ１８色谱柱,甲醇和水梯度洗脱,用二极管矩阵检测（２５４ｎｍ）的ＨＰＬＣ法,１２ｍｉｎ内同时测定了五氯硝基苯－多菌灵可湿性粉剂中２种有效成分的含量。该法简便、快速、准确,标准偏差分别为０．１２％和０．１５％,相对标准偏差分别为０．４６％和１．４４％。     

反相高效液相色谱法同时测定桑叶提取物中芸香甙和槲皮素的含量

用Ｐ１００型高效液相色谱系统、ＤＬ－８００色谱工作站、ＹＷＧ－Ｃ１８色谱柱,以甲醇－水－磷酸体系（６０∶４０∶０．４,Ｖ／Ｖ／Ｖ）为流动相分离并同时测定了桑叶提取物中芸香甙与槲皮素的含量。芸香甙、槲皮素含量与峰面积呈良好的线性关系。芸香甙的变异系数为１．９８％,回收率为１０４．０％;槲皮素的变异系数为９．８％,回收率为１０３．２％。     

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。     

在线热辅助甲基化-气相色谱法分析棉籽仁中的脂肪酸组成

建立了分析棉籽仁中脂肪酸组成的在线热辅助甲基化-气相色谱法。将0.3 mg棉籽仁样品与2 μ L三甲基氢氧化硫（0.2 mol/L）加入裂解器,在350℃下进行甲基化反应,通过气相色谱仪进行分离分析,共检测到8种脂肪酸甲酯成分,分别为亚油酸（C18：2）、油酸（C18：1）、棕榈酸（C16：0）、硬脂酸（C18：0）、肉豆蔻酸（C14：0）、棕榈油酸（C16：1）、花生酸（C20：0）和二十二酸（C22：0）,不饱和脂肪酸的相对含量为66.30%~72.54%,其中亚油酸的相对含量为43.20%~53.61%,相对峰面积的相对标准偏差（RSD）小于10%（n=5）。通过分析5组棉籽仁样品与3种食用油中的脂肪酸组成,结果表明不同产地的棉籽仁中的脂肪酸组成差异不明显,且棉籽仁中的脂肪酸组成与玉米油最为接近,相似度为0.960~0.992。该方法简单、快速、准确,适合分析棉籽仁中的脂肪酸组成。     

Ionic Liquid-Based Extraction of Fatty Acids from Blue-Green Algal Cells Enhanced by Direct Transesterification and Determination Using GC × GC-TOFMS

Blue-green algae commonly referred to as cyanobacteria are known to grow in freshwater bodies when they are provided with suitable growth conditions such as nutrients, temperature and light. Algae biomass is known to contain a large amount of lipids, such as saturated and unsaturated fatty acids. In this study, fatty acids from algal cells were extracted using a newly developed extraction protocol using ionic liquid enhanced by direct transesterification at an elevated temperature. The identification and quantification of fatty acids was performed using gas chromatography coupled to a time-of-flight mass spectrometer (GC × GC-TOFMS). The extracted fatty acids were dominated by those with carbon chain of C16 and C18; [i.e. 7-hexadecenoic acid (C16:1) and hexadecanoic acid (C16:0) for C16, whereas C18 includes γ-linolenic acid (γ-C18:3); linoleic acid (C18:2); linolenic acid (C18:3); 6,9,12,15-octadecatetraenoic acid (C18:4); oleic acid (C18:1) and octadecanoic acid (C18:0)]. The obtained fatty acid composition was then compared with that obtained by organic solvent extraction using a mixture of chloroform and methanol. Statistical evaluation was performed using one-way ANOVA and found that there was no statistically significant difference (P = 0.908) between the two extraction methods, a finding which indicates the usefulness of ionic liquid as a solvent to replace volatile organic solvent to minimize environmental pollution.     

Method development for the analysis of trans-fatty acids in hydrogenated oils by capillary electrophoresis

A novel capillary electrophoresis methodology using UV indirect detection (224 nm) for the analysis of trans-fatty acids in hydrogenated oils was proposed. The electrolyte consisted of a pH 7 phosphate buffer at 15 mmol x L(-1) concentration containing 4 mmol.L(-1) sodium dodecylbenzenesulfonate, 10 mmol x L(-1) polyoxyethylene 23 lauryl ether (Brij 35), 2% 1-octanol and 45% acetonitrile. Under the optimized conditions, ten fatty acids, C12:0, C13:0 (internal standard), C14:0, C16:0, C18:0, C18:1c, C18:1t, C18:2cc, C18:2tt and C18:3ccc were baseline-separated in less than 12 min. The proposed methodology was applied to monitor the formation of trans-fatty acids during hydrogenation of Brazilnut oil. A crude oil sample (42.1% linoleic acid, 37.3% oleic acid, 13.4% palmitic acid, and 7.0% stearic acid) was mixed with 0.25% of a nickel-based catalyst and submitted to two independent hydrogenation conditions: 175 degrees C, 3 atm, 545 rpm for 60 min (GH(1) sample), and 150 degrees C, 1 atm, 545 rpm for 30 min (GH(2) sample). For the most severe hydrogenation condition (higher temperature and pressure, under longer reactional period), a more complete conversion of linoleic and oleic acids into stearic acid occurred with concomitant formation of the trans-species, elaidic acid (C18:1t). For the milder hydrogenation procedure that generated sample GH(2), larger amounts of linoleic and oleic acids remained, in addition to the transformations already observed in the GH(1) sample.     

Characteristics of fatty acids and essential oil from sweet fennel (Foeniculum vulgare Mill. var. dulce) and bitter fennel fruits (F. vulgare Mill. var. vulgare) growing in Turkey

Oil content in sweet and bitter fennels was obtained 12.22% and 14.41%, respectively. The C(18:1 c6), C(18:2), C(18:1 c9) and C(16:0) acids corresponding to approximately 97% of total oil was recorded as principal fatty acids. The ratios of essential oil from sweet and bitter fennels were found similar (average 3.00%). trans-Anethole, estragole and fenchone were found to be the main constituents in both fennels. The compound with the highest value in the two oil samples was trans-anethole as 95.25% (sweet) and 75.13% (bitter). While estragole was found in bitter fennel oil in a remarkable amount (15.51%), sweet fennel oil contained small amounts of estragole (2.87%). Fenchone was found <1% in sweet and approximately 5% in bitter fennel. p-Anisaldehyde in bitter fennel essential oil, and alpha-pinene and gamma-terpinene in sweet fennel essential oil were not recorded, and these compounds were found very low or <1%.     

Extraction and separation of volatile and fixed oils from berries of Laurus nobilis L. by Supercritical CO2

Isolation of volatile and fixed oils from dried berries of Laurus nobilis L. from Tunisia have been obtained by supercritical fractioned extraction with carbon dioxide. Extraction experiments were carried out at a temperature of 40 degrees C and pressures of 90 and 250 bar. The extraction step performed at 90 bar produced a volatile fraction mainly composed of (E)-beta-ocimene (20.9%), 1,8-cineole (8.8%), alpha-pinene (8.0%), beta-longipinene (7.1%), linalool acetate (4.5%), cadinene (4.7%), beta-pinene (4.2%), alpha-terpinyl acetate (3.8%) and alpha-bulnesene (3.5%). The oil yield in this step of the process was 0.9 % by weight charged. The last extraction step at 250 bar produced an odorless liquid fraction, in which a very small percentage of fragrance compounds was found, whereas triacylglycerols were dominant. The yield of this step was 15.0 % by weight. The most represented fatty acids of the whole berry fixed oil were 12:0 (27.6%), 18:1 n-9 (27.1%), 18:2 n-6 (21.4%), and 16:0 (17,1%), with the 18:1 n-9 and 18:2 n-6 unsaturated fatty acids in particular averaging 329 microg/mg of oil.     

Determination of cuticular and internal fatty acids of Chorthippus brunneus males and females using HPLC‐LLSD and GC–MS

Insects are of growing significance in veterinary medicine and human healthcare; therefore, an understanding of their biology is very important. The cuticular and internal fatty acid compositions of Chorthippus brunneus males and females have been studied for the first time. The lipids of males and females were separated into classes of compounds using high‐performance liquid chromatography with a laser light scattering detector. The free fatty acid (FFA) fractions obtained by HPLC were silylated and then analyzed by GC–MS. The cuticular lipids of males contained 15 saturated, four unsaturated with even‐numbered and two unsaturated with odd‐numbered carbon chains, FFAs ranging from C8 to C25. The major free fatty acids in males were C16 (20.8%), C18:2 (8.5%), C18:1 (32.9%) and C18 (24.4%). The cuticular lipids of females contained 17 saturated, four monounsaturated and two diunsaturated free fatty acids ranging from C8 to C30. The major cuticular fatty acids in females were C16 (25.1%), C18:2 (6.2%), C18:1 (23.7%) and C18:0 (33.2%). The internal FFAs of males consisted of 20 compounds ranging from C8 to C26. Four of these compounds were detected as major compounds: C16 (14.1%), C18:2 (21.6%), C18:1 (38.0%) and C18 (22.5%). Among 18 internal free fatty acids of females, C16 (22.3%), C18:2 (10.9%), C18:1 (40.2%) and C18 (20.5%) were the most abundant compounds. The following cuticular fatty acids present in the lipids of females were absent in the lipids of males: C26, C27 and C30. On the other hand, only C24 was absent from the cuticular lipids of females. Only C10 and C24 internal fatty acids present in the lipids of males were absent in the lipids of females. Copyright © 2016 John Wiley & Sons, Ltd.     

<em>In Vitro</em> Anti-diabetic Activities and Chemical Analysis of Polypeptide-k and Oil Isolated from Seeds of <em>Momordica charantia</em> (Bitter Gourd)

The amino acid and fatty acid composition of polypeptide k and oil isolated from the seeds of Momordica charantia was analysed. The analysis revealed polypeptide k contained 9 out of 11 essential amino acids, among a total of 18 types of amino acids. Glutamic acid, aspartic acid, arginine and glycine were the most abundant (17.08%, 9.71%, 9.50% and 8.90% of total amino acids, respectively). Fatty acid analysis showed unusually high amounts of C18-0 (stearic acid, 62.31% of total fatty acid). C18-1 (oleic acid) and C18-2 (linoleic acid) were the other major fatty acid detected (12.53% and 10.40%, respectively). The oil was devoid of the short fatty acids (C4-0 to C8-0). Polypeptide k and oil were also subjected to in vitro α-glucosidase and α-amylase inhibition assays. Both polypeptide k and seed oil showed potent inhibition of α-glucosidase enzyme (79.18% and 53.55% inhibition, respectively). α-Amylase was inhibited by 35.58% and 38.02%, respectively. Collectively, the in vitro assay strongly suggests that both polypeptide k and seed oil from Momordica charantia are potent potential hypoglycemic agents.     

Analysis of thermal,oxidative and cold flow properties of methyl and ethyl esters prepared from soybean and mustard oils

Oilseed crop with high oil content and promising ecological adaptability are potential sources for competitive biodiesel production. This study investigates the scope of utilizing biodiesel development through the methyl and ethyl ester from soybean and mustard oil as an alternative fuel. Methyl and ethyl esters of oils having different fatty acids compositions such as soybean (SOME and SOEE) and mustard oil (MUME and MUEE) were prepared by transesterification with methanol and ethanol in the presence of an alkali-KOH catalyst. The gas chromatographic (GC) analysis of oil samples revealed that primary fatty acid composition in soybean oil was linoleic acid (C_18:2, 51.93%), followed by oleic acid (C_18:1, 22.82%), palmitic acid (C_16:0, 11.56%), linolenic acid (C_18:3, 5.95%) and stearic acid (C_18:0, 4.32%). Whereas, the main components in mustard oil were erucic acid (C_22:1, 32.81%), oleic acid (C_18:1, 24.98%), eicosenoic acid (C_20:1, 10.44%), linolenic acid (C_18:3, 8.61%) and palmitic acid (C_16:0, 2.80%). The physicochemical properties (acid value, iodine value, calorific value, flash point, pour point etc.) of methyl and ethyl ester samples were estimated and found to be within the acceptable range of ASTM D6751 standards specifications. The prepared esters and oil samples were examined for cold flow properties by differential scanning calorimetry (DSC). Results revealed better cold flow properties for MUME (−2.55 °C) and MUEE (−3.10 °C) than SOME (3.21 °C) and SOEE (1.83 °C) due to more unsaturated fatty acid content in MU. Thermal and oxidative stability of samples was determined by thermogravimetric analysis (TG) and differential thermal analysis (DTA). The thermal and oxidative stability ranking of the samples was in the order of oil > methyl esters > ethyl esters.