自动石墨消解-电感耦合等离子体质谱法同时测定发酵面制品中的铅、砷、镍、铝、铬

目的建立自动石墨消解-电感耦合等离子体质谱法同时检测发酵面制品中的铅、砷、镍、铝、铬元素。方法采用微波消解技术进行样品消化,电感耦合等离子体质谱仪对消化后的样品进行检测,内标法进行定量分析。结果 5种元素质量浓度在0.2~30μg/L范围内呈现良好的线性,相关系数(r2)均不低于0.995;检出限为铅6.1μg/kg、砷0.32μg/kg、镍5.4μg/kg、铝12.3μg/kg、铬2.4μg/kg;各元素加标回收率在85%~110%之间;重复性相对标准偏差在5.0%以内(n=6)。结论该方法前处理简单、检出限低、重复性好、检测结果准确,可用于发酵面制品中的铅、砷、镍、铝、铬的检测。     

自动石墨消解-ICP-MS法测定预制肉制品中的9种重金属残留

为建立自动石墨消解-ICP-MS法检测预制肉制品中的铅、铬、砷、铁、锰、铜、钴、铝、镍金属残留方法,利用自动石墨消解仪对样品进行消化前处理,处理后的样品溶液用ICP-MS检测,内标法定量分析。结果表明:铅、铬、砷、铁、锰、铜、钴、铝、镍元素质量浓度在0.20～50μg/L范围内有良好的线性关系,相关系数(R2)在0.990以上;检测限:铅0.01 mg·kg~(-1)、铬0.017 mg·kg~(-1)、砷0.033 mg·kg~(-1)、铁0.014 mg·kg~(-1)、锰0.02 mg·kg~(-1)、铜0.01 mg·kg~(-1)、钴0.027 mg·kg~(-1)、铝0.037 mg·kg~(-1)、镍0.014 mg·kg~(-1);加标回收率(低点0.06 mg·kg~(-1),中点1.0mg·kg~(-1)和高点6.0 mg·kg~(-1))在81.4%～105.8%之间;重复性(n=6)相对标准偏差低于10%。该方法具有前处理简单、污染小、检测灵敏度高等优点。     

ICP-MS法同时测定预包装食品中的5种常见元素

建立ICP-MS法同时测定预包装食品中的铅、砷、钙、铜、铝、镍。采用微波消解消化样品,ICP-MS检测样品,利用内标法定量分析。结果表明,各物质质量浓度在0.5~25μg/L范围内线性关系良好,线性相关系数均大于0.995;检测限为:铅0.04μg·L~(-1)、砷0.01μg·L~(-1)、钙0.04μg·L~(-1)、铜0.10μg·L~(-1)、铝0.01μg·L~(-1)、镍0.02μg·L~(-1);样品加标回收率均在90%~110%之间;精密度RSD(n=6)在5.0%以内,重复性RSD(n=6)在5.0%以内。试验证明该方法操作简单、灵敏度高、检测结果准确可靠。     

自动石墨消解-ICP-MS法检测水产罐头中的铅、铬等7种金属

试验建立了全自动石墨消解仪消解水产罐头样品,电感耦合等离子体质谱法同时检测铅、铬、铝、砷、锡、镍、铜金属残留的分析方法。水产罐头样品经全自动石墨消解仪消解,消解酸选择HNO3-H2O2(3︰2,V/V),消解完毕后上机分析,内标法定量检测。结果显示,铅、铬、铝、砷、锡、镍、铜7种金属在质量浓度0.1~20μg/L范围内具有良好的线性关系,相关系数(R2)均高于0.995;检测限为:铅0.004 mg·kg^-1,铬0.006 mg·kg^-1,铝0.012mg·kg^-1,砷0.009 mg·kg^-1,锡0.0014 mg·kg^-1,镍0.008 mg·kg^-1和铜0.005 mg·kg^-1;加标范围在0.1~10μg/L质量浓度内,回收率在87.4%~106.2%之间;重复性和精密度RSD(n=6)均在5.0%以内。该方法具有简便、污染小、准确、前处理简单等优点。     

微波消解ICP-MS法检测肉制品中的铅、铬、镉、铝、锰、锡

建立肉制品中的铅、铬、镉、铝、锰、锡6种元素的电感耦合等离子体质谱分析方法。采用微波消解对样品进行前处理,消化后的样品经电感耦合等离子体质谱(inductively coupled plasma mass spectrometry,ICP-MS)检测,利用内标法进行定量分析。结果表明,6种元素线性范围为0.2μg/L~100μg/L,线性相关系数(R2)均大于0.995;检测限:铅0.02μg/L、铬0.03μg/L、镉0.02μg/L、铝0.01μg/L、锰0.04μg/L、锡0.10μg/L;方法加标回收率均在84.9%~104.2%之间;以重复性考察方法重现性,RSD(n=6)在2.71%~4.38%以内;以精密度考察方法稳定性,RSD(n=6)在2.72%~4.28%以内。此方法简单、快速、准确度高、灵敏度高,可以用于肉制品中6种元素的常规分析检测。     

超级微波消解-ICP-MS法测定食用油中铅、砷、铜

建立了超级微波消解-电感耦合等离子体质谱仪(ICP-MS)测定食用油中铅、砷、铜的方法。以5 m L硝酸、1 m L双氧水和0. 2 m L硫酸作为消解用酸体系,在消解程序升温温度依次为110、170、230℃下,采用超级微波消解法对食用油进行前处理,采用ICP-MS法测定食用油中的铅、砷、铜。结果表明:标准曲线在0～50 ng/m L铅、砷、铜质量浓度范围内线性关系良好,相关系数在0. 999 6～1. 000 0之间,相对标准偏差(RSD)为3. 2%～8. 3%,检出限为铅0. 5 ng/m L、砷0. 1ng/m L、铜0. 1 ng/m L,加标回收率均在82. 1%～101. 5%之间。该方法准确、快速、方便,适用于食用油中铅、砷、铜的测定。     

ICP-MS法测定蓝莓中的15种无机元素

建立电感耦合等离子体质谱仪(ICP-MS)同时测定蓝莓浆果中15种无机元素的方法.样品经微波消解处理后,用Sc、Ge、In、Bi作为内标,在碰撞模式下,用ICP-MS检测蓝莓中的无机元素.其中,钠、镁、钾、钙、铁元素的线性范围为0～5000 μg/L;铬、锰、钴、铜、锌、砷、硒、钼、镉和铅元素的线性范围为0～50μg/...     

微波消解-ICP-MS测定酸角浸膏中的铅、砷、镉、铬

目的 采用电感耦合等离子体发射光谱-质谱仪(ICP-MS)测定酸角浸膏中铅、砷、镉、铬的含量。方法 使用微波消解仪消解酸角浸膏试样, 外标法定量。结果 铅、砷、镉、铬在0~50.00 μg /L的浓度范围内线性关系良好, 相关系数为≥0.9995, 方法检出限为: 铅2.0 μg /kg、砷19.0 μg /kg、镉1.0 μg /kg、铬9.0 μ g /kg, 加标回收率的范围为81.5%~119.1%。结论 该方法试样处理简便, 测定速度快, 结果准确, 适用于酸角浸膏的检测。     

ICP-MS法同时测定云南野生牛肝菌中5种金属元素

建立微波消解-电感耦合等离子体质谱(Inductively coupled plasma-mass spectrometry,ICP-MS)法测定云南省6种常见野生牛肝菌中5种金属元素(总砷、铅、总汞、镉、铬)。采用HNO3和H2O2作为消解酸体系,样品采用微波消解进行前处理,通过ICP-MS法同时测定牛肝菌中5种金属元素的含量。结果表明,总汞在0~48μg/L范围内呈现良好的线性关系,铅、总砷、镉、铬在0~200μg/L范围内呈现良好的线性关系(r0.999),方法的检出限在0.001~0.01 mg/kg,平均回收率为95.22%~100.08%,精密度的RSD小于5%,重复性的RSD均小于2%。建立的方法具有简便、快速、准确度好等优点,可推荐用于食用菌中金属元素的定量测定,并为其质量监控提供参考。     

ICP-MS检测康艾注射液中多种金属元素残留方法研究

目的建立电感耦合等离子体质谱(ICP-MS)检测康艾注射液中的铅、砷、铬、镉、铝、铜、锡的分析方法。方法采用微波消解技术对康艾注射液进行前处理,处理后的样品溶液采用ICP-MS检测,内标法定量。结果 7种待测元素在浓度0.1～50μg/L范围内具有良好的线性,相关系数R~2均在0.995以上;7种待测元素检出限在0.04～0.52μg/kg之间;各元素加标回收率在87.5%～105.3%之间;重复性及精密度RSD(n=6)在5.0%以内。结论该方法具有前处理简单、污染小、检出限低、检测结果准确等优点,适用于康艾注射液中金属残留的分析检测。     

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.     

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.     

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。     

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.     

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.     

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.