气相色谱-质谱联用分析比较浙江海风藤茎及叶挥发油成分

分析比较了浙江海风藤茎及叶两个部位挥发油的化学成分.采用水蒸气蒸馏法提取,运用气相色谱-质谱联用法结合计算机检索对其化学成分进行分析和鉴定,用气相色谱面积归一法测定各组分的相对百分含量.从浙江海风藤茎及叶挥发油中分别鉴定出了30和37种化合物,其中有20种是它们共同的成分,含量最高的是喇叭茶萜醇(茎含39.62%,叶含36.80%).已鉴定挥发油成分占总挥发油含量分别为92.18%及93.15%.     

厦漳地区原水DOM的3-DEEM-FRI表征与分析研究

采用三维荧光光谱结合荧光区域积分分析法（3DEEM-FRI）研究了厦漳地区江东泵站、北溪水闸、汀溪水库、莲花水库、坂头水库以及石兜水库原水中溶解性有机物（DOM）的荧光特性、污染特征及其他水质指标与各荧光区域积分体积之间的相关性。结果表明,三种荧光组分-荧光类蛋白质组分（组分Ⅰ,C1）、荧光类蛋白质组分（组分Ⅱ,C2）以及类富里酸组分（组分Ⅲ,C3）在所调查水样中均有显著检出,而溶解性微生物代谢产物组分（组分Ⅳ,C4）在莲花、坂头以及石兜水样中有检出,类腐殖酸组分（组分Ⅴ,C5）在所调查水样中检出不明显;不同水体中同一组分的相对含量差别不大,其中荧光类蛋白质组分占比（P_{1, n}+P_{2, n}）均在60%以上,组分Ⅲ（P_{3, n}）与组分Ⅳ占比（P_{4, n}）均在10%～20%之间,组分Ⅴ占比（P_{5, n}）小于6%;荧光特征参数（1.28β∶α<0.97）显示水体中DOM具有典型的陆源与自生源混合输入的污染特征,组分Ⅰ、组分Ⅱ与组分Ⅳ之间具有同源性特征;TOC与总标准荧光积分体积（Ф_T,n）之间具显著的相关性（R2=0.979 34）,NH+₄-N与组分Ⅳ的标准荧光积分体积（Ф_4,n）之间相关性较好（R2=0.827 98）,而类腐殖质的相对含量（P_{3, n}+P_{5, n}）与SUVA之间的R2为0.703 25。研究表明,3DEEM-FRI分析法可用于识别江湖水库型原水DOM的组成及污染来源,同时还可以实现对TOC含量、NH+₄-N含量以及水体腐殖化程度的有效追踪和指示。     

新疆温郁金块根挥发油化学成分研究

采用水蒸气蒸馏法提取了新疆产温郁金块根的挥发油,经气相-质谱联用仪分析其成分,得到52种组分,采用峰面积归一化法计算各组分的相对含量,结果确定了其中45种化合物的结构。确定了新疆温郁金块根挥发油中主要含新莪术二酮(13.29%)、莪术二酮(10.05%)、β-榄香烯(2.54%)等抗肿瘤活性成分,为进一步全面研究开发温郁金提供科学依据。     

基于可见-近红外光谱的咖啡品牌鉴别研究

利用可见-近红外光谱技术对市场上三种不同品牌咖啡品种进行鉴别。分别采用主成分分析法与BP神经网络结合和小波变换与BP神经网络结合两种组合模型进行分析预测。利用主成分分析法与小波变换的数据压缩功能和BP神经网络的学习预测能力实现对不同品牌咖啡的鉴别。实验采用３个品种共60个样本建立模型,30个样本进行品种鉴别,结果表明,两种鉴别模型的咖啡品种鉴别率均为100%。同时也表明,小波变换用于数据压缩无论是在压缩时间上还是在压缩能力上都优于主成分分析法。说明通过小波变换和BP神经网络相结合建立模型进行不同品牌咖啡鉴别具有分析速度快,鉴别能力强的特点,为快速鉴别纯品咖啡提供了新的方法,同时也为确定不同品牌咖啡选用咖啡豆品种奠定了基础。     

乳化降粘剂的红外光谱和核磁共振谱的分析研究

采取一系列分离方法对一种高效乳化降粘剂进行分离与纯化.用红外光谱对各组分的官能团结构进行了鉴定,用核磁共振氢谱及电喷雾离子质谱对相应组分进行了分析.推断其组分有表面活性剂烷基酚聚氧乙烯醚和N-月桂酰肌氨酸钠,在降粘剂固体含量部分中分别占26.6%和19.3%.高分子组分为聚丙烯酸丁酯,含量为9.0%.通过气相色谱-质谱分析技术对小分子助剂进行了分析,有2-乙基己醇,十二醇,十四醇.通过定性定量分析,该样品有高达27.2%的氢氧化钠及很少量的氯化钠,其余为水.     

川芎挥发油化学成分GC/MS分析

使用水蒸气蒸馏法提取川芎中的挥发油,利用气相色谱-质谱联用技术对川芎化学成分进行分离鉴定,采用色谱峰面积归一化法确定各成分的相对含量。分析结果表明,共分离出53种组分,鉴定了其中的34个组分,占挥发油组分总量的64.42%。     

气相色谱法测定二咖啡酰奎尼酸原料药中的有机溶剂残留量

以1,2-二氯乙烷作为内标,气相色谱法定量检测二咖啡酰奎尼酸原料药中7种有机溶剂残留量。色谱柱：DB-624,30m×0.32mm×1.8μm,载气为H2,检测器为FID,采用程序升温的方法。7种残留溶剂的线性关系良好（r〉0.9914）,回收率为92.5%—98.5%,最小检出限量均为0.01%。本方法简便、灵敏、准确,可用于二咖啡酰奎尼酸原料药残留溶剂的质量控制。     

气红联用法研究标准桃金娘油的化学成分

采用毛细管气相色谱-傅里叶变换红外光谱联用技术法(气红联用,GC-FTIR),结合计算机检索对标准桃金娘油化学成分进行分析和鉴定,用气相色谱面积归一化法测定各组分的相对百分含量;经毛细管色谱从标准桃金娘油中分离出12个峰,并且采用FTIR法确认了所含的化合物。标准桃金娘油主要成分为三种单萜,分别为1,8-桉叶素、D-柠檬烯和α-蒎烯,含量分别为46.35%,36.83%和14.70%,三者占总量的97.88%,分析结果与GC-MS分析相一致。由于GC-FTIR分析能确定出经气相色谱分离后的有机物的异构体,故与GC-MS分析相比较,此法具有更广泛的应用价值。该研究可为综合利用开发桃金娘科植物提供科学依据。     

黄腐植酸的化学组成

对云南寻甸褐煤氧化降解产物黄腐植酸分子量小于500的组分进行了GC-MS、红外分析及官能团含量的定性定量分析.结果显示,黄腐植酸中小分子组分含有大量的羧基,酚羟基含量较少.GC-MS研究表明,二元羧酸构成了含量上优势化合物,乙二酸、丙二酸、丁二酸为含量较高的化合物;羟基羧酸类以α-羟基丙酸含量最高;醇类、芳香类羧酸、酸性萜类、氨基酸类化合物含量少;内酯类、稠环芳烃环状化合物含量很低或不存在.     

土荆芥果实挥发油成分及抗氧化能力

对土荆芥果实挥发油成分及抗氧化能力进行研究。采用质谱技术与Kovats指数相结合对土荆芥果实挥发油化学成分进行分离鉴定;利用清除1,1-二苯基苦基苯肼(DPPH)自由基的方法,评价土荆芥果实挥发油的抗氧化能力。土荆芥果实挥发油中分离鉴定了11种组分,其相对含量占挥发油总质量的98.94%,含量较高组分是α-异松油烯(60.44%),驱蛔素(15.57%),对-聚伞花素(12.76%)和α-松油烯(4.51%)。清除DPPH自由基IC50为6.9053mg.mL-1。土荆芥果实挥发油主要成分是萜烯类化合物;并具有一定的抗氧化能力。     

Subcritical water extraction of chlorogenic acid from green coffee beans

A method for extracting chlorogenic acid (CA) avoiding the use of expensive organic solvents was developed based on studies of the processing of green coffee beans with subcritical water. The content of chlorogenic acid in the obtained extracts was determined by high-performance liquid chromatography (HPLC). The method was shown to be more effective than the known ethanol extraction procedure.     

Using elemental profiles and stable isotopes to trace the origin of green coffee beans on the global market

A broad elemental profile incorporating 54 elements (Li, Be, B, Na, Mg, Al, P, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Rb, Sr, Y, Mo, Pd, Ag, Cd, Sn, Sb, Te, Cs, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Er, Tm, Yb, Re, Ir, Pt, Au, Hg, Tl, Pb, Bi and U) in combination with δ(2) H, δ(13) C, δ(15) N and δ(18) O was used to characterise the composition of 62 green arabica (Coffea arabica) and robusta (Coffea canephora) coffee beans grown in South and Central America, Africa and Asia, the four most internationally renowned areas of production. The δ(2) H, Mg, Fe, Co and Ni content made it possible to correctly assign 95% of green coffee beans to the appropriate variety. Canonical discriminant analysis, performed using δ(13) C, δ(15) N, δ(18) O, Li, Mg, P, K, Mn, Co, Cu, Se, Y, Mo, Cd, La and Ce correctly traced the origin of 98% of coffee beans. Copyright ? 2012 John Wiley & Sons, Ltd.     

基于激光诱导击穿光谱技术的咖啡豆中咖啡因含量快速检测方法

应用激光诱导击穿光谱(LIBS)技术研究了快速检测咖啡豆中咖啡因含量的可行性。将咖啡豆磨粉压成片状作为采集LIBS光谱数据的样本,应用原子吸收分光光度计测量每个样本中咖啡因的含量。应用基线校正,小波变换和归一化等数据预处理方法;针对基于全部变量的偏最小二乘(PLS)模型会出现过拟合,分别应用回归系数和主成分分析(PCA)选择特征变量,并建立了基于特征变量的PLS和BP神经网络模型。结果表明：基于回归系数所选特征变量的PLS模型中,建模集相关系数R_c=0.96,预测集R_p=0.91;基于PCA提取特征变量的PLS模型中,R_c=0.94,R_p=0.90;基于PCA所选特征变量的BP神经网络模型中,R_c=0.96,R_p=0.96。两种方法所提取特征变量均对应C,H,O,N,Na,Mn,Mg,Ca和Fe,且基于上述两种方法所选特征变量的PLS模型均对预测集样本有较好的预测结果,说明上述元素与咖啡因含量存在联系,应用回归系数和PCA选择的特征变量是有效的,但是咖啡豆内C,H,O,N,Na,Mn,Mg,Ca,Fe与咖啡因含量的确切关系需要进一步研究。基于PCA所选特征变量的BP神经网络模型有更优的预测结果,说明所选特征变量适用于不同的建模方法。研究表明LIBS技术结合化学计量学方法可以实现咖啡豆中咖啡因含量的快速检测。     

Brewing coffee? – Ultra-sonication has clear beneficial effects on the extraction of key volatile aroma components and triglycerides

Ultrasound has been investigated as a new technique for brewing coffee. A two-level factorial experimental design was conducted to identify the effects of ultra-sonication on the extraction of coffee components during ultrasonically-assisted coffee brewing. Different brews were produced by aqueous extraction from roasted ground coffee beans with sonication, and without it as a control, by varying coffee concentration (5% and 10% w/w), temperature (25 and 50 °C) and sonication time (1 and 5 min). These brews were tested for antioxidant capacity (using the ABTS assay), caffeine and triglycerides (using quantitative NMR spectroscopy) and specific aroma/flavour volatiles (using headspace SPME-GC-MS). Additional observations of colour, foaming, body and flavour were also reported. Ultrasound was found to significantly increase the extraction of caffeine, triglycerides and several of the key volatile compounds from coffee, although it did appear to decrease the concentration of antioxidants over the controls, especially with longer time and higher temperature. Furthermore, all the sonicated samples exhibited a lighter caramel colour and lower foam formation which were attributed to their higher triglyceride content. The increased concentration of triglycerides and volatiles were by far the most outstanding responses.     

Effect of sugars on liquid-vapour partition of volatile compounds in ready-to-drink coffee beverages

The effect of sugars (sucrose, lactose, glucose, fructose, 10%w/v) on the liquid-vapour partition of selected volatile compounds of coffee beverages has been investigated in espresso coffee and ready-to-drink (RTD) canned coffee prepared and obtained by using the same Arabica roasted coffee beans blend. Aroma composition of coffee beverages has been preliminary investigated by headspace-gas chromatography (HS-GC) and solid phase microextraction-HS-GC-mass spectrometry to characterize the volatile pattern of the systems and to evaluate the effects of sugars on the aroma release/retention. Then, the liquid-vapour partition coefficient (k) of 4 selected key aroma compounds (diacetyl, 2,3-pentanedione, ethylpyrazine, hexanal) was determined in water, sugars solutions as well as RTD coffee brews added with the same sugars (10%w/v). Sugars added in coffee beverages affected the release of the volatiles and thus its aroma profile with differences due to the type of added sugar and coffee brew type. The k values of the selected volatile compounds resulted different depending on the model system composition (water, coffee brew) and sugar type added. In particular, melanoidins as well as other non-volatile components (lipids, acids, carbohydrates) in the RTD coffee brews could be implied in the change of k of the volatile compounds in respect to that observed in water. The effects of the sugar type on the release/retention of the four key coffee aroma compounds were partly explained in terms of 'salting out' especially for the more polar volatile compounds and in the sucrose-added model systems. The change of chemical and physico-chemical properties of the water and brews induced by the sugars as well as the occurrence of interactions between volatile compounds and non-volatile components may be implied in the reduction of the vapour partition of the aroma compounds. Copyright ? 2012 John Wiley & Sons, Ltd.     

三种鸢尾属植物的脂溶性成分比较分析

用GC-MS对矮紫苞鸢尾、细叶鸢尾和蓝花喜盐鸢尾这3种鸢尾植物的脂溶性成分进行了比较分析。从矮紫苞鸢尾中鉴定出11种脂溶性成分,占总峰面积的85.55%,相对含量较高的化合物为14-甲基十五烷酸甲酯(36.55%),(Z,Z)-9,12-十八烷二烯酸甲酯(10.05%);细叶鸢尾的脂溶性成分共鉴定出13种成分,占总峰面积的71.32%,相对含量较高的化合物为2-甲基-琥珀酸二丁酯(13.83%)、(Z,Z)-8,11-十八烷二烯酸甲酯(11.90%);蓝花喜盐鸢尾的脂溶性成分共鉴定出15种成分,主要以甲酸酯类为主,占总峰面积的90.54%,相对含量较高的化合物为十四烷酸甲酯(30.70%)、14-甲基-十五烷酸甲酯(26.83%)、十八烷酸甲酯(23.57%)。结果表明,从矮紫苞鸢尾中鉴定出的11种化合物为首次从该植物中发现。3种鸢尾属植物的脂溶性成分主要以有机酸酯类化合物为主,在其种类和相对含量上有一定的相似性,为该属植物化学分类提供一定的依据。     

20种代表性主产区蚕豆样品矿物元素含量及其与烹煮品质的相关性分析

探索矿物元素对蚕豆的烹煮加工适用性影响,本研究选取全国各主产区的20种主要栽培蚕豆,采用ICP-MS方法对子叶和种皮中11种矿物元素进行测定,并对蚕豆的灰分和矿物元素含量与烹煮品质指标进行相关性分析,结果显示蚕豆子叶和种皮中矿质元素含量都存在显著差异,矿物元素含量与蚕豆烹煮品质具有一定的相关性,子叶中矿物元素对于烹煮指标的影响由大至小依次为铝、镁、锌、锰、矿物质总量、灰分含量、磷、铜、钾、硒;种皮中的矿物质含量对烹煮指标的影响依次为镁、铜、钙、铝、钾、矿物质总量。     

Determination of potassium in several plants and study of potassium transfer to different beverages, including tequila, by measurement of 40K

Measurement of ⁴⁰K was used for determination of potassium concentrations in leaves of agave and maguey cactus leaves, and coffee beans of various origins. The procedure was also used to study potassium transfer to tequila (alcoholic drink made of agave cactus), and the cactus and coffee infusions using ⁴⁰K as a natural radioactive tracer. Counting of ⁴⁰K in Marinelli containers with the aid of a low background NaI(Ti) scintillation detection system for 12–24 hours was employed. The method appeared to be simple and suitable for determination of potassium concentrations in large samples, which eliminates homogeneity problems.