电感耦合等离子体质谱法快速测定烟用接装纸中砷、铅、镉、铬、镍、汞的研究

建立了电感耦合等离子体质潜法测定烟用接装纸中砷、铅、镉、铬、镍、汞含量的方法,并采用该方法测定了25个接装纸样品中的砷、铅、镉、铬、镍、汞含量.结果表明:①砷、铅、镉、铬、镍、汞的平均回收率在97.9%～101.6%之间;日内重复性变异系数<2%,日间重复性变异系数<5%;检出限分别为0.001 mg/kg,0.002 mg/kg,0.008 mg/kg,0.004 mg/kg,0.007 mg/kg,0.016 mg/kg.②所测25个接装纸样品中,7个样品超过砷的限量标准1 mg/kg,2个样品超过铅的限量标准5 mg/kg,镉、铬、镍、汞的含量全部低于其限量标准.     

干巴菌中部分重金属元素及无机砷、 甲基汞含量分析

目的检测干巴菌中5种重金属总砷、总汞、铅、镉、铬及无机砷和甲基汞的含量,探讨干巴菌对重金属的生物富集作用。方法采用电感耦合等离子体质谱法检测总砷、总汞、铅、镉含量,采用液相原子荧光光度计联用检测无机砷、甲基汞的含量。结果 31份干巴菌样品中总砷、总汞、铅、镉的检出率均为100%,无机砷的检出率为50%,甲基汞在全部样品中均未检出。昆明的干巴菌样品中砷含量较高,达0.46 mg/kg;曲靖的干巴菌中铅含量有0.9997 mg/kg;镉含量较高,为0.46 mg/kg。结论总体来看不同地区的干巴菌中总砷、总汞、镉、铬、无机砷和甲基汞的含量处于较低水平,但铅含量偏高。干巴菌对重金属没有特异性吸收富集能力。     

我国部分经济海产食品中砷、铅、镉、汞含量的测定与分析

对我国部分经济海产食品中的砷、铅、镉、汞的含量进行了测定.结果表明,海产动物(干品)中总砷含量为1.29～27.76mg/kg,无机砷含量为零,铅含量为0.22～9.90mg/kg,镉含量为0～11.83mg/kg,汞的含量为0～3.04ng/kg;海藻(干品)中总砷含量较高,46.68～101.88mg/Kg,除羊栖菜外,其它海藻的无机砷含量为零.铅含量为6.13～18.31mg/kg,镉含量为1.97～12.05mg/kg,汞含量为0～5.17ng/kg.虽然个别样品重金属含量高于国家标准,但总体是安全的.     

微波消解-电感耦合等离子体质谱法同时测定粮食中6种元素含量

目的建立微波消解-电感耦合等离子体质谱法(inductively coupled plasma mass spectrometry,ICP-MS)同时测定粮食中铅、砷、铬、镉、汞、铝6种元素的含量,了解粮食中重金属污染状况。方法针对汞元素易挥发和易在仪器管路残留的问题,优化赶酸温度、金溶液浓度、内标元素等主要影响因素。采用硝酸-过氧化氢作为消解体系,加入金溶液,微波消解后70℃赶酸,采用ICP-MS法检测粮食加工品中6种元素的含量。结果 200个样品中6种元素含量的测定结果为:铅0.083~0.10 mg/kg;砷0.017~0.10 mg/kg;铬0.059~0.19 mg/kg;镉0.0025~0.038 mg/kg;汞0.0054~0.015 mg/kg;铝4.9~29 mg/kg。除铝元素目前缺失限量标准外,铅、砷、铬、镉、汞含量的合格率为100%。方法检出限为0.0004~0.5 ng/mL,加标回收率为88.0%~106.0%,相对标准偏差为0.6%~2.5%,相关系数r为0.9992~0.9999。结论该方法简便快捷、汞残留少、准确度和精密度高,满足粮食及相关产品中铅、砷、铬、镉、汞、铝等多元素的同时测定,能够有效监测粮食中重金属污染状况。     

食用动物皮中重金属本底值研究

目的 研究食用动物皮中重金属本底值, 更加有效地实施对动物皮及其制品中的重金属含量监测。方法 从河南省14个省辖市的市场上采购286份食用动物皮样品进行重金属含量的检测, 5种重金属分别为铅含量(以Pb计)、镉含量(以Cd计)、总砷含量(以As计)、铬含量(以Cr计)、汞含量(以Hg计)。以GB 2762—2017《食品安全国家标准 食品中污染物限量》中肉类中重金属含量的限量值作为参考。结果 铬的超标率为8.5%, 检出范围为未检出(not detected, ND)~1.71 mg/kg, 铅的超标率为7.7%, 检出范围为ND~1.33 mg/kg, 镉的超标率为3.1%, 检出范围为ND~0.172 mg/kg。结论 本研究可以为进一步制定食用动物皮中重金属的限量标准和市场的科学监管提供依据。     

微波消解ICP-MS测定海产品中的砷铅镉汞

砷、铅、镉、汞在食品中为有害元素,食用被这些有害元素污染的海产品严重威胁人们的健康甚至是生命。国家卫生标准和其他涉及到海产品的行业标准中砷、铅、镉和汞都是规定必须监控的元素。国家卫生标准规定海产品中铅≤0.2mg/Kg,砷≤0.1mg/Kg,镉≤0.1mg/Kg,汞≤0.5mg/Kg。采用微波消解前处理样品,电感耦合等离子质谱同时测定海产品中的砷、铅、镉、汞,测定方法的检出限为0.003-0.046 ng/mL,精密度在0.98%到4.26%之间,回收率在89%到116%之间,对实际样品的测定中,按照国家的限量标准,砷有3个样品超标,镉有2个样品超标,铅、汞的含量没有超标。     

昆明市售坚果中5种有害元素的监测

目的了解昆明市售坚果中铅、砷、汞、铬、镉5种有害元素的污染情况。方法昆明市14个区县采集共140份坚果,采用浓硝酸为消解液,石墨消解仪对样品进行前处理消解,电感耦合等离子体质谱同时测定坚果中的5种有害元素的含量,内标法定量。结果样品中汞、镉、砷、铅及铬的检出率依次为35%、45%、65%、100%和100%。从坚果类别分析,检出率为葵花籽(81.2%)花生(80%)松子(77.5%)南瓜子(67.5%)西瓜子(61.3%)开心果(60%)=葡萄干(60%)杏仁(58.7%)核桃(48.3%),从有害元素含量分析,检测含量为铬(0.961 mg/kg)砷(0.057 mg/kg)铅(0.053 mg/kg)镉(0.047 mg/kg)汞(0.009 mg/kg)。2份样品中铅元素含量超过标准限值,超标率为1.4%。结论样品有害元素的含量较低,但检出率较高,相关部门应加强对坚果在贮存、加工、包装过程中的监督管理,保障消费者的食品安全和健康。     

国内外红茶重金属及稀土元素的安全性评价

以国内外红茶为材料,采用电感耦合等离子体质谱仪(ICP-MS)测定样品中铜(Cu)、铅(Pb)、砷(As)、汞(Hg)、铬(Cr)、镉(Cd)以及16种稀土元素含量(以氧化物总量ΣRe Os计)。在此基础上根据《绿色食品茶、有机茶、食品中污染物限量》等国家和行业标准中对重金属含量进行安全性评价。结果表明,所有样品中Pb含量均低于5μg/g,满足国标中对茶叶Pb的限量要求。根据《有机茶》标准,1个样品Pb含量不符合要求,3个样品Cu含量不满足该标准的限量要求。从《绿色食品茶叶》标准来看,3个样品不满足该标准对重金属的限量要求。从NY 659—2003《茶叶中铬、镉、汞、砷及氟化物限量》标准的要求来看,2份样品Cr含量超出该标准。稀土元素的分析结果表明,10个样品稀土氧化物总量超标(2 mg/kg)。总体来看,该批茶叶样品重金属的合格率为72.97%。     

便携式能量色散X射线荧光光谱法快速检测玩具中5种元素

本文研究并建立了便携式能量色散X射线荧光光谱仪直接快速测定玩具样品中铅、镉、铬、汞、砷含量的分析方法。方法精密度实验表明,各元素相对标准偏差(RSD,n=11)在1.59%~6.21%之间,铅、汞、砷的检测限均小于2 mg/kg,镉、铬的检测限小于3 mg/kg。方法用于塑料类和皮革类玩具样品分析,测定结果与湿法分析结果一致,能够满足实际样品铅、镉、铬、汞、砷元素同时快速分析的要求。     

不同牧场鲜牛乳中重金属含量的研究

目的 考察4个牧场的生鲜牛乳的重金属污染情况和评估鲜牛乳原料的安全性。方法 采用国家标准检测方法对4个牧区的生牛乳中重金属铬、铅、汞以及金属砷进行检测,其中使用石墨炉原子吸收光谱法测定铅和铬的含量,使用氢化物发生原子荧光光谱法测定总砷含量,使用原子荧光光谱分析法测定总汞的含量。结果 铬含量最高值为DR牧场的0.052 mg/kg,铅含量最高值为YY牧场的6.60 μg/kg,总汞含量最高值为YY牧场的0.83μg/kg,总砷含量范围为 5.10 μg/kg～7.20 μg/kg。结论 实验测得的四种元素含量均远低于安全标准限量值,4个牧场的鲜牛乳未受到重金属污染。     

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.     

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.     

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.     

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.     

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.