超高效液相色谱快速测定卷烟主流烟气中7种挥发酚

为快速准确地测定卷烟烟气中的对-苯二酚、邻-苯二酚、间-苯二酚、苯酚、对-甲酚、邻-甲酚和间-甲酚,建立了同时测定卷烟主流烟气中7种挥发酚的超高效液相色谱( UPLC)方法.采用1％醋酸水溶液对捕集烟气粒相物的剑桥滤片超声萃取20 min,萃取液过滤后通过Acquity UPLC BEH C18色谱柱分离,以水相中含7.0×10-3 mol/Lβ-环糊精(β-CD)的流动相进行梯度洗脱,采用荧光检测器进行分析.该方法的相对标准偏差( RSD)为1.15％～5.79％,回收率为90％～102％,检测限为0.04 ～ 0.35 μg/支,分析时间9 min.该法适合批量卷烟主流烟气中7种挥发酚的快速分析.     

两种抽吸模式下卷烟主流烟气中主要酚类的释放量比较

为了解不同抽吸方式对卷烟主流烟气中主要酚类化合物释放量的影响,建立了一种利用超高效液相色谱(UPLC)快速分析卷烟主流烟气中邻-苯二酚、对-苯二酚、间-苯二酚、苯酚、邻-甲酚、间+对-甲酚的方法,并采用该方法测定了ISO模式和加拿大卫生部(Health Canada)深度抽吸模式下38个卷烟样品烟气中这7种主要酚类的释放量。结果表明:①方法检测限为16～43 ng/支,回收率94%～102%,RSD4%;②与ISO抽吸模式相比,在HC深度抽吸模式条件下卷烟主流烟气中主要酚类化合物释放量显著提高。     

β-环糊精在卷烟主流烟气中简单酚类分析中的应用

为准确测定卷烟烟气中对-甲酚和间-甲酚异构体,进行了流动相中添加β-环糊精(β-CD)前后用反相高效液相色谱法分离检测卷烟烟气中7种有害酚的比较试验。结果表明:①流动相中添加5.29×10-3mol/Lβ-CD水溶液,可同时将对-甲酚、间-甲酚、邻-苯二酚、间-苯二酚、对-苯二酚、苯酚和邻-甲酚分离;②7种酚的回收率为92.9%～102.4%,RSD1.78%～4.33%。该法可用于卷烟烟气中这7种有害酚的测定。     

硅烷化-GC/MS联用测定卷烟主流烟气中7种酚类化合物

为准确测定卷烟主流烟气中7种酚类化合物(苯酚,邻、间、对-甲酚,邻、间、对-苯二酚)的释放量,建立了一种N-甲基-N-(三甲基硅烷)三氟乙酰胺(MSTFA)硅烷化-气相色谱-质谱(GC/MS)法。在标准抽吸条件下,用剑桥滤片捕集2支卷烟的烟气粒相物,加入内标(苯酚-d5)标准溶液和三氯甲烷超声萃取10 min,取1 m L萃取液于色谱瓶中并加入30μL MSTFA,压盖密封后在60℃下衍生化20 min,然后进行GC/MS分析。结果表明:(1)该方法的相对标准偏差(n=8)为2.6%~5.6%,加标回收率93.1%~102.9%,检出限0.005~0.026μg/支。(2)与标准方法相比,该方法可实现间-甲酚和对-甲酚的良好分离,能够准确测定卷烟主流烟气中7种酚类化合物的释放量。(3)采用该方法与现有标准方法对25个卷烟样品检测的结果一致性较好,无显著差异。该方法检测结果稳定性、重复性好,准确性和精确度高,适用于卷烟主流烟气中7种酚类化合物的检测。     

高效液相色谱法测定卷烟主流烟气中的苯并[a]芘

为了测定卷烟主流烟气中苯并[a]芘,考察了萃取条件、弗罗里硅土净化条件和色谱分离条件,建立了测定卷烟主流烟气中苯并[a]芘的高效液相色谱-荧光检测法,并采用该方法和国标法测定了肯塔基参考卷烟3R4F和国内参比烤烟以及国内50个牌号卷烟样品烟气中的苯并[a]芘。结果表明:①用环己烷超声萃取40 min效果较好;②用Agilent ZORBAX Eclipse PAH作色谱柱,乙腈和水为流动相,梯度洗脱,流速2.0 mL/min,30 min内苯并[a]芘色谱峰可以和杂质峰有效分开;③该法的平均回收率在98.13%～101.36%之间,RSD在1.29%～4.32%之间;④该方法的测定结果与国标法较为一致,二者不存在显著性差异。该方法适合卷烟主流烟气中苯并[a]芘的检测。     

高效液相色谱法测定卷烟滤嘴中截留的主要酚类化合物

为准确测定卷烟滤嘴截留主流烟气中的主要酚类化合物,通过考察滤嘴切割方式、萃取液、萃取方式、萃取时间等前处理条件,建立了一种快速、准确测定卷烟滤嘴中对苯二酚、间苯二酚、邻苯二酚、苯酚、对甲酚、间甲酚和邻甲酚7种酚类化合物截留量的高效液相色谱(HPLC)方法,并采用该方法在6家实验室对7种不同滤嘴卷烟样品进行了比对实验。结果表明:1将卷烟抽吸后的滤嘴从烟支端向近嘴端纵向划开后,用50 m L萃取液(1%乙酸+79%甲醇+20%水,体积分数)在室温下超声萃取30 min时,可将卷烟滤嘴中截留的7种主要酚类化合物萃取完全。27种酚类化合物在0.04~4.00μg/m L浓度范围内线性关系良好(R2均大于0.999),回收率为93.35%~104.50%,相对标准偏差(RSD)小于7.3%。36家实验室对7种卷烟样品滤嘴截留的7种酚类化合物检测结果的RSD均小于15%,其中5种酚类化合物在10%以下。该方法适用于卷烟滤嘴截留主流烟气中7种酚类化合物的测定。     

卷烟主流烟气中烟草特有亚硝胺的液质联用分析

采用0.1mol/L醋酸铵水溶液萃取、固相萃取纯化和高效液相色谱-三级四极杆质谱法测定了12种卷烟样品主流烟气中4种烟草特有亚硝胺(TSNAs)。结果表明:①NNN、NAT、NNK和NAB的检测限分别为0.07、0.05、0.05和0.04ng/mL,回收率在94.0%～103.5%之间,相对标准偏差分别为3.02%、4.19%、6.10%和6.62%;②2种进口混合型卷烟主流烟气中的总TSNAs均远远高于10种国产烤烟型卷烟。该法适合批量卷烟主流烟气中TSNAs的定量分析。     

二维液相色谱法测定卷烟主流烟气中的间-苯二酚及其他酚类化合物

建立了测定卷烟主流烟气中7种主要酚类化合物的二维液相色谱方法,考察了中心切割和二维分离间-苯二酚的色谱条件,以及二维液相色谱系统的稳定性,并采用该方法测定了12种卷烟样品主流烟气中的这7种酚类化合物.结果表明:①中心切割和二维液相色谱能够有效分离间-苯二酚与干扰物质;②中心切割和二维液相色谱不影响卷烟主流烟气中其它6种酚类化合物的准确定量;③12种卷烟样品主流烟气中间-苯二酚的释放量为0.72～2.15μg/支.     

国内外主要品牌卷烟主流烟气中烟草特有N-亚硝胺的对比分析

本文采用气相色谱-热能分析仪(GC-TEA)对卷烟主流烟气中主要4种烟草特有N-亚硝胺(TSNAs)进行了分析;优化了前处理过程及仪器分析条件;建立了使用经抗坏血酸处理的玻璃纤维滤片收集卷烟主流烟气,用二氯甲烷萃取卷烟主流烟气中的TSNAs,萃取液经碱性氧化铝层析柱纯化,TSNAs通过GC-TEA定量检测的分析方法;并对国内外较有代表性的98种卷烟样品中的TSNAs进行了系统的分析测定。结果表明,混合型卷烟主流烟气中TSNAs的含量显著高于烤烟型卷烟;国外混合型卷烟中NNK的含量高于国内混合型卷烟。这些研究结果为制定我国卷烟烟气中TSNAs含量限量标准、建立技术壁垒提供了可靠的技术基础。      

烟气中烟草特有亚硝胺LC-MS/MS分析方法的改进

为更加快速准确地测定不同类型卷烟烟气中TSNAs含量,进行了液相色谱串联质谱(LC-MS/MS)法测定条件改进试验。结果表明:①10 mmol/L乙酸铵水溶液可以替代100 mmol/L乙酸铵水溶液作萃取剂;②萃取液经0.45μm水相滤膜过滤后可直接进行LC-MS/MS仪分析;③同时用NNN-d4,NNK-d4,NAT-d4,NAB-d4作内标定量结果更为准确;④TSNAs的检出限为0.06~0.14 ng/mL,回收率91%~100.6%,RSD 0.76%~5.42%。该方法适用于混合型、烤烟型卷烟样品主流烟气中TSNAs的定量分析。     

Natural pigments: carotenoids, anthocyanins, and betalains--characteristics, biosynthesis, processing, and stability

Pigments are present in all living matter and provide attractive colors and play basic roles in the development of organisms. Human beings, like most animals, come in contact with their surroundings through color, and things can or cannot be acceptable based on their color characteristics. This review presents the basic information about pigments focusing attention on the natural ones; it emphasizes the principal plant pigments: carotenoids, anthocyanins, and betalains. Special considerations are given to their salient characteristics; to their biosynthesis, taking into account the biochemical and molecular biology information generated in their elucidation; and to the processing and stability properties of these compounds as food colorants.     

Hormones, metabolites, and reproduction in Holsteins, Jerseys, and their crosses

Holsteins (HH), Jerseys (JJ), and their crosses in first (n=157) and second (n=107) lactation were used to determine if reproduction, progesterone (P4), insulin-like growth factor 1 (IGF-1), insulin, nonesterified fatty acids (NEFA), and milk production differed between genetic groups. Thirty-four cows were Holstein-Jersey (HJ) crosses, 46 were Jersey-Holstein (JH) crosses, 48 were purebred Holsteins (HH), and 29 were purebred Jerseys (JJ) in first lactation, whereas the second-lactation animals included 23 HJ, 35 JH, 35 HH, and 14 JJ. Blood samples were collected weekly for the first 10 wk postpartum. Analyses were conducted using the MIXED, chi-square, and GLIMMIX procedures (SAS Institute Inc., Cary, NC). Seasons of calving were cold (November to May) and hot (June to October) and were combined with year to form 8 year-seasons. Days open and number of services were affected by genetic group. The HH were open 169±8 d, which was greater than HJ (143±9 d), JJ (132±10 d), and JH (127±8 d). The HH had 2.4±0.1 services per pregnancy, which was greater than JH (1.9±0.1), but not different from HJ (2.1±0.2) or JJ (2.1±0.2). Concentrations of NEFA were greater in lactation 2 (0.52±0.02 mEq/L) than in lactation 1 (0.45±0.02 mEq/L) and decreased over the 10-wk period. Concentrations of NEFA were greater in the cold season except in yr 3. Insulin in lactation 1 (0.81±0.03 ng/mL) was greater than in lactation 2 (0.72±0.03 ng/mL); insulin decreased to wk 2 then gradually increased. The HJ had the greatest insulin concentrations (0.87±0.04 ng/mL) and the JJ had the lowest (0.66±0.04 ng/mL), and IGF-1 gradually increased over the 10-wk period. Milk production (actual yield in the first 305 d, not adjusted for fat and protein) was affected by genetic group, lactation number, year-season, and wk 1 insulin. The HH produced 10,348±207 kg of milk, which was greater than the HJ (9,129±230 kg), the JH (9,384±190 kg), and the JJ (7,080±240 kg). Milk production in lactation 2 (9,676±163 kg) was greater than that in lactation 1 (8,294±160 kg). The JJ (10.3±4.7%) had the highest frequency of mastitis. The chance of getting mastitis for HH (1.1±0.9%) differed from that for HJ (9.4±4.1%), JH (8.1±3.4%), and JJ (10.3±4.7%). Genetic group affected hormones and metabolites, which may partially explain differences in reproductive measures and milk yield.     

Water-, oil-, and soil-repellent treatment of textiles,artificial leather,and leather

Several products are on the market to realize water-, oil-, and soil-repellent properties on textiles or textile-related materials. To make an adequate and fast rating of repellent properties of finished textiles, different drop tests according to AATCC and ISO standards are commonly used. For evaluation of the repellent properties of solid substrates against different liquids often contact angle measurements are performed. The aim of the work presented here is to determine and evaluate the repellent effects gained by the application of three different finishing agents on three different substrates, such as polyester fabric, artificial leather, and leather. The main questions are at that point: It is possible to gain similar repellent effects with the same finishing product applied on different substrates? Do the different testing methods lead to comparable results? Is there a relation to the repellency against everyday consumer products as red wine, ice tea, or coffee? This article should help the reader to evaluate different testing methods and the influence on common substrates.     

卷烟中锂、铬、镍、铜、砷、硒、钼、镉、铊和铅含量分析

采用微波消解-电感耦合等离子体质谱法测定了41个牌号烤烟型卷烟和雪茄烟样品烟丝中的锂、铬、镍、铜、砷、硒、钼、镉、铊和铅含量,并按照类型和价位对卷烟中这10种有害元素含量进行了统计分析。结果发现:①卷烟中锂和铜的含量较高,铊的含量很低,铬、镍、镉、铅、砷、硒和钼7种元素的平均含量为0.55～4.42μg/g;②雪茄烟中铬、镍、砷、钼、镉、铊和铅的含量一般高于烤烟型卷烟,而硒元素的含量则相反,但差别较小;烤烟型卷烟中锂和铜的含量与雪茄烟没有显著差异;③高档卷烟中的锂、镍、镉、铊和铬含量较低,而砷、铅的含量较高;不同价位卷烟的铜、硒和钼含量差异不显著。     

Tyrosinase, Laccase, and Peroxidase in Mushrooms (Agaricus, Crimini, Oyster, and Shiitake)

Enzyme assays and electrophoresis were used to monitor the activity of tyrosinase, laccase, and peroxidase in Agaricus bisporus (common cultivated button mushrooms and Crimini mushrooms), Oyster, and Shiitake mushrooms. The three enzymes could be differentiated using specific substrates and inhibitors. Tyrosinase seemed to be the major phenol oxidase in the Agaricus strains, while Oyster and Shiitake mushrooms had much lower levels. Peroxidase activity was low or undetectable in all types examined. Control of enzymatic browning in different mushroom types may depend upon the distribution of different oxidases within any given type.     

Polyphenols, Anthocyanins, Ascorbic Acid, and Radical Scavenging Activity of Rubus, Ribes, and Aronia

ABSTRACT: Total polyphenols, total anthocyanins, and reduced ascorbic acid were evaluated in berries belonging to the genera Rubus, Ribes, and Aronia by means of spectrophotometric and high-performance liquid chromatography (HPLC) techniques. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity of the fruit extracts was tested. Total polyphenols ranged from 140.6 to 888.5 mg/100 g fresh weight (FW), total anthocyanins ranged from 22.0 to 460.5 mg/100 g FW, and reduced ascorbic acid ranged from 12.4 to 153.8 mg/ 100 g FW. The average EC50 values for Aronia melanocarpa, Ribes nigrum, Ribes rubrum, Rubus fruticosus, and Rubus idaeus were 1.8, 2.8, 5.3, 6.4, and 8.2 mg FW, respectively. The results indicate that the fruits tested are good sources of natural antioxidants.     

Simultaneous and Direct Determination of As, Bi, Pb, Sb, and Se and Co, Cr, Cu, Fe, and Mn in Milk by Electrothermal Atomic Absorption Spectrometry

Tungsten permanent modifier with coinjection of Pd(NO₃)₂ and W–Ru permanent modifiers are proposed for the direct and simultaneous determination of As, Bi, Pb, Sb, and Se (group 1) and Co, Cr, Cu, Fe, and Mn (group 2), respectively, in milk by graphite furnace atomic absorption spectrometry. The performance of modifiers was evaluated by means of thermal behavior of analytes, sensitivity, atomic signal profile, repeatability, graphite tube lifetime, and background intensity. An air-assisted pyrolysis step was necessary to quantitative elimination of the organic matter. After methods optimization, 14 commercial milk samples were analyzed. The found concentrations of As, Bi, Pb, Sb, Se, Co, and Cr were lower than their limit of detection (2.13, 2.21, 1.49, 1.63, 2.05, 1.0, and 1.2 μg L⁻¹, respectively). Concentrations of Cu, Fe, and Mn were in the 1.58–5.74 μg L⁻¹, 9.79–49.3 μg L⁻¹, and 2.25–4.08 μg L⁻¹ intervals, respectively. The limits of detection for Cu, Fe, and Mn were 1.7, 5.3, and 2.0 μg L⁻¹, respectively. The accuracy of methods was checked after analysis of two milk standard materials. Results for Cr, Cu, Fe, Mn, Pb, and Mn were in agreement with certified values of SRMs at the 95% confidence level. Accuracy was also evaluated by addition–recovery tests and recoveries in the 86–127% range were obtained for all elements. The use of pretreat platform of graphite tubes with W or W–Ru allowed enlarging the lifetime of atomizer in 750 heating cycles.     

Capsicum--production, technology, chemistry, and quality. Part V. Impact on physiology, pharmacology, nutrition, and metabolism; structure, pungency, pain, and desensitization sequences

The spice Capsicum is the fruit of the cultivated species of the genus Capsicum (family, Solanaceae), C. annuum principally, and C. frutescens L. to a lesser extent. A third variety of C. annuum var. annuum fruits, the large-sized, fleshy bell capsicum is used as a fresh vegetable and valued for its aroma, color, and crisp texture, but with no pungency. This variety is not considered in this series of reviews covering primary processing, production, international trade, chemistry, and biochemistry of functional components--the red keto carotenoids, the aromatic volatiles and the pungent capsaicinoids in Parts I to III. The valid qualitative aspects correlating the specific components of capsicum and their sensory responses are critically covered in Part IV. In this the concluding part of the series of reviews, the significant preference of the spice for initially evoking an aversive response, its potent physiological and pharmacological effects, and the aspects of structure-activity relationships of the pungent stimuli of the capsaicinoids are reviewed. The beneficial effects particularly associated with long usage by some ethnic groups and its safe consumption levels, with a critical review of the studies on the gastrointestinal tract, the cardiovascular system, the sensory system, thermoregulation, nutritional impacts, and an overview of the five series is also detailed.