福建省地产茶叶中14种元素的分析与研究

目的了解福建省不同地区不同茶叶中铅、砷、铜、铁、锰、锌、镉、铝、硒、镍、铬、钴、锡、铋等14种元素的含量分布,为茶叶资源的开发利用提供科学依据。方法从福建省主要产茶地区的产地和市场随机抽取9个茶叶品种共112份样品,用微波消解-电感耦合等离子体质谱法(ICP-MS)测定样品中14种元素含量。结果 9种茶叶中14种元素的含量水平分别为:锰135～1 797 mg/kg,铝69～1 126 mg/kg,铁37～371 mg/kg,锌3.93～90.05 mg/kg,铜2.25～43.66 mg/kg,镍0.95～7.40 mg/kg,铅0.29～5.45 mg/kg,铬0.10～2.39 mg/kg,钴0.018～0.67 mg/kg,硒0.020～0.68 mg/kg,镉0.014～0.24 mg/kg,砷0.023～0.30 mg/kg,锡0.010～0.49 mg/kg,铋0.006～0.073 mg/kg,铅合格率为99.1%,铬、镉、砷合格率为100%。结论福建省地产茶叶中都富含锰、铝、铁、锌、铜。铬、镉、砷、铅等有害元素污染水平较轻,且不同地区不同茶叶中元素含量存在差异。     

块菌中多种重金属及不同形态砷、汞含量分析

目的测定块菌中4种重金属(砷、铅、汞、镉)及无机砷、有机汞含量并进行分析评价。方法采用电感耦合等离子体质谱法(inductively coupled plasma mass spectrometry, ICP-MS)检测块菌种总砷、总汞、铅、镉含量,采用液相-原子荧光光谱联用法(liquid chromatography-atomic fluorescence spectrometry, LC-AFS)检测块菌中无机砷、有机汞含量。结果块菌中无机砷和有机汞含量极低,但铅、镉含量较高。铅的含量为0.8282 mg/kg,镉的含量为0.4040 mg/kg。结论块菌作为一种完全生长在地下的大型真菌,具有较高的重金属吸附富集能力,应加强对此类野生菌的重金属污染物监测。     

云南省水生蔬菜中5种典型重金属含量特征及健康风险评估

目的 分析云南16个不同地区157份水生蔬菜中分布广、毒性强的重金属元素(镉、铅、铬、汞、砷)含量特征, 并对其进行健康风险评估。方法 样品经微波消解处理后, 采用电感耦合等离子体质谱法(inductively coupled plasma mass spectrometry, ICP-MS)检测水生蔬菜中镉、铅、铬、汞、砷5种重金属元素的含量。采用重金属目标风险系数(target hazard coefficient, THQ)法对水生蔬菜中典型重金属可能产生的健康风险进行定量评估。结果 云南各地区水生蔬菜中5种重金属均有不同程度检出, 镉、铅、铬、汞、砷平均值分别为(0.006±0.019)、(0.029±0.043)、(0.036±0.075)、(0.002±0.002)、(0.108±0.164) mg/kg, 本研究采集157份样品中共6份超标样品, 整体合格率为96.2%。结论 云南省不同种类水生蔬菜中重金属含量总体水平较低, 大部分种类水生蔬菜重金属健康安全风险较低。但是, 芦蒿和慈姑两类蔬菜有着较高的健康风险。不同人群方面, 儿童受到的健康风险相比成年人更高。     

安徽芡实营养特性分析

以安徽产芡实为原料,分别对其中主要营养组分、氨基酸组成和矿物元素进行了分析.分析结果显示,芡实是一种淀粉基原料,其中淀粉含量为72.27%,粗蛋白质含量与大米接近,为9.72%,脂肪含量较低.芡实蛋白中必需氨基酸总量达39.9,远高于标准必需氨基酸模式27.0.矿物元素的分析结果显示,芡实中含有丰富的镁、钠、钙、钾、铁、锌、锰等矿物元素,其中镁含量高达367.10mg/kg,硒含量为0.032mg/kg,四种重金属含量均未超出食品卫生标准的限量规定.此外,芡实中还含有丰富的酚类物质(0.79mg/g).     

冻干松茸粉中总砷及无机砷的含量测定

目的测定冻干松茸粉中总砷及无机砷的含量。方法采用电感耦合等离子体质谱法(inductively coupled plasma mass spectrometry,ICP-MS)、原子荧光光谱法(atomic fluorescence spectrometry,AFS)、液相色谱-电感耦合等离子体质谱法(liquid chromatography with inductively coupled plasma mass spectrometry,LC-ICP/MS)3种方法分别测定松茸中总砷及无机砷含量。结果ICP-MS、AFS测定冻干松茸粉中总砷含量分别为71.7、0.556 mg/kg,LC-ICP/MS测定冻干松茸粉中无机砷含量为0.0114 mg/kg。结论冻干松茸粉中砷主要以有机态存在,且不同检测方法以及前处理方式都会对实验结果产生影响。     

水生蔬菜提取物的抗氧化活性分析及其对菜籽油的抗氧化作用

研究七种常见水生蔬菜不同部位提取物的抗氧化活性以及对油脂抗氧化的效果。采用ABTS自由基清除法、DPPH自由基清除法检测菱角、芡实、莲藕、水芋头、茭白、荸荠和慈姑不同部位的醇提物、水提物的抗氧化活性,烘箱法测定对菜籽油过氧化值的影响。在30种提取物中DPPH自由基清除能力较强的三种提取物IC50值分别为:芡实壳醇提物(0.03 mg/mL)芡实壳水提物(0.04mg/m L)=菱角壳醇提物(0.04mg/m L);ABTS自由基清除能力较强的三种提取物Trolox含量分别为芡实壳醇提物(1.42g/g)芡实壳水提物(1.41 g/g)菱角壳醇提物(1.15 g/g);添加0.1%浓度的五种提取物第7 d的POV值分别为23.86 meq/kg、24.06 meq/kg、23.53meq/kg、24.43 meq/kg、22.40 meq/kg,五种提取物的油脂抗氧化效果均不如0.1%浓度的BHA。30种水生蔬菜提取物中,芡实壳和菱角壳的醇提物、水提物DPPH自由基清除能力最强,芡实壳醇提物、水提物ABTS自由基清除能力最强;芡实壳水提物、芡实壳醇提物、菱角壳水提物、菱角壳醇提物以及藕节醇提物对菜籽油有一定抗氧化的效果,但效果弱于相同剂量的BHA。     

2016~2018年苏州市水生蔬菜重金属污染状况分析及健康风险评价

目的 研究苏州市地方特产水生蔬菜中重金属污染情况, 评价苏州居民经水生蔬菜膳食途径摄入的重金属对人体存在的健康风险。方法 2016~2018年在苏州市10个区县连续采集8种共198份水生蔬菜样品, 采用国家标准方法检测样品中铅、镉、总汞和总砷含量, 按GB 2762-2017《食品安全国家标准 食品中污染物限量》判定重金属超标情况; 利用单因子污染指数和内梅罗综合污染指数评价不同种类水生蔬菜中铅、镉、总汞和总砷的污染程度; 采用暴露情景假设的方法和简单分布模型(确定性评估)的方法评价水生蔬菜中重金属的健康风险。结果 水生蔬菜中铅和总砷的超标率分别为5.29%(10/189)和0.60%(1/166), 镉和总汞无超标样品, 铅、镉、总汞和总砷检测平均值分别为0.0518、0.0066、0.0007和0.0526 mg/kg。3个年份样品的重金属污染水平不完全相同, 水生蔬菜总汞水平存在种类间差异; 重金属污染水平之间存在相关性。水生蔬菜中4种重金属单项污染指数均小于或等于0.7, 处于优良水平; 综合污染指数均小于0.7, 处于安全水平。苏州地区水生蔬菜中的铅污染对成人及95%的儿童均不会产生健康危害, 但对高食物消费暴露的儿童(5%)可能产生潜在的健康影响; 镉、总汞、总砷污染对成人和儿童均不会产生健康危害。结论 苏州市水生蔬菜中重金属污染水平较低; 水生蔬菜铅污染可能对小部分儿童存在潜在健康危害。     

电感耦合等离子体质谱法直接测定料酒中的7种微量元素

目的:建立料酒中铜、锰、锌、硒、铁、镉、铅(Cu,Mn,Zn,Se,Fe,Cd,Pb)7种微量元素的电感耦合等离子体(ICP)-质谱(MS)直接测定法。方法:样品经1%硝酸溶液稀释10倍后,采用ICP-MS法直接分析稀释液中的铜、锰、锌、硒、铁、镉、铅等微量元素。结果:测定的17种不同料酒中,铜、锰、锌、硒、铁、镉、铅含量的均值分别为457.0,141.7,239.7,1.60,433.5,1.10,3.41μg/kg。各元素回收率为91.2%~106.7%,相对标准偏差均小于3.8%,检出限范围为0.003~0.657μg/L。结论:该方法具有准确、快速、简便等优点,完全满足料酒中铜、锰、锌、硒、铁、镉、铅等微量元素的检测要求。     

湘西产猕猴桃重金属含量分析及矿物质营养价值评价

目的了解湘西产猕猴桃中重金属污染状况及评价猕猴桃中矿物质的营养价值。方法从湖南湘西地区采集5种猕猴桃,经消解处理,用电感耦合等离子体质谱仪、原子荧光光度计、可见分光光度计测定其中重金属和矿物质的含量,并根据食品中污染物限量和中国居民膳食营养素参考摄入量分别对重金属和矿物质进行评价。结果湘西产猕猴桃中常量元素都以钾含量最高,达到2.52~3.96 mg/g,而钠含量极低,仅为1.08~4.67 mg/kg。在5种猕猴桃中湘西野生的铁、锌含量最高,湘西东红的锰、铜含量最高,凤凰红心的铬、硒含量最高。5种猕猴桃中铅含量为0.0037~0.019 mg/kg,镉含量为0.00070~0.0024 mg/kg,铅、镉、砷和汞的含量均处于较低水平。结论湘西产猕猴桃中铅、镉含量均低于国家标准规定的限量。在正常推荐食用量的情况下,5种猕猴桃中的矿物质无过量摄入风险。猕猴桃能为人体提供丰富的钾、铜、铬,将它们与磷、钙、铁、锌、硒含量较为丰富的食物搭配食用能使各种矿物质总体上摄入更加充足平衡。     

原子光谱法测定金花葵花瓣及种子中微量元素

金花葵微量元素的测定多采用原子光谱法,但因实验条件、样本预处理方法不一致,各测定方法间的重现性和可比性较差。采用原子吸收分光光度计测定微量元素铜、镁、铁、锰、铅、锌,采用原子荧光分光光度计测定微量元素硒。实验详细研究了微波消解与电热板消解法两种消解方法对含量测定的影响,对金花葵花瓣和种子中的微量元素含量进行了比较。结果表明微波消解法更有利于微量元素含量的测定,精密度与重现性更高。金花葵种子与花瓣相比,种子中的微量元素锌、镁、锰等含量均比花瓣中高,金花葵花瓣及种子中都含有微量元素硒,种子中的微量元素含量达0.063 5 mg/kg,花瓣中的含量为0.027 2 mg/kg。微量元素铅含量没有超标,金葵花种子的药用价值更高。     

Survey of iron,zinc, calcium,copper, lead,and cadmium in rice samples grown in Iran

In the present study ninety nine polished white rice samples were collected in three areas, all over Lorestan Province located in the west of Iran, and analysed for six elements by Flame Atomic Absorption Spectrometry (FAAS). For individual elements, Zinc (Zn) showed the highest concentration among the analysed essential elements with a mean of 28.6 mg kg^?1 and next to copper (Cu) of 22.8 mg kg^?1. Analysis of the essential and toxic elements for possible inter-area variation by ANOVA showed that there are significant differences between the areas. There was no significant difference between areas for Zn concentrations. Most of the samples nearly contained world wide average concentration of iron (Fe) and Zn in rice grains that were reported by various researches. But, the content of calcium (Ca) in the rice samples produced in Lorestan Province were much lower than other countries, meanwhile Cu concentrations were much higher than other studies. Cadmium (Cd) and Lead (Pb) concentrations in the sampled rice were lower in comparison with their upper limits (0.1 and 0.2 mg kg^?1 for Cd and Pb, respectively) approved by Iranian Ministry of Health. Therefore, it can be concluded that there is no health problems result from Lorestan rice consumption, for these two elements.     

Lead, chromium, tin, iron and cadmium in foods in welded cans

The levels of lead, chromium, tin, iron and cadmium in fruit and vegetables in welded tinplate cans were determined by atomic absorption spectrophotometry. The levels found were compared with those in foods in soldered tinplate cans and fresh foods. The results show that the lead levels in foods in welded cans were much lower than those in similar foods in soldered cans. Foods in unlacquered welded cans contain much more lead, chromium and tin than foods in lacquered welded cans. The cadmium and iron levels in canned fruit and vegetables in welded cans were similar to those found in the corresponding fresh foods.     

隆回富硒区野生水芹中Ca、Mg、Fe、Se、Zn、Cu含量研究

利用原子吸收光谱法研究隆回富硒区野生水芹中Ca、Mg、Fe、Se、Zn、Cu六种元素的含量。结果表明:隆回富硒区野生新鲜水芹菜中Zn、Cu、Fe、Mg、Ca、Se分别达到1.4277×10-4、0.7853×10-4、90.4767×10-4、321.8782×10-4、1313.3938×10-4、1.46×10-4μg/g,水分含量为13.4%的干水芹菜中含量分别为69.01、9.42、1066.38、3540.66、14312.92、0.154μg/g。除Zn的含量低于芹菜外,其它各元素的含量均高于所列的常见蔬菜,其中Fe含量是普通蔬菜的45～7.5倍、Ca含量是普通蔬菜的13-1.6倍、Se含量是普通蔬菜的9.7～2.4倍。     

Engaging in paced mating, but neither exploratory, anti-anxiety, nor social behavior, increases 5alpha-reduced progestin concentrations in midbrain, hippocampus, striatum, and cortex

Sequential actions of 17beta-estradiol (E(2)) and progesterone (P(4)) in the hypothalamus and the P(4) metabolite, 5alpha-pregnan-3alpha-ol-20-one (3alpha,5alpha-THP), in the midbrain ventral tegmental area (VTA) respectively mediate the initiation and intensity of lordosis of female rats and may also modulate anxiety and social behaviors, through actions in these, and/or other brain regions. Biosynthesis of E(2), P(4), and 3alpha,5alpha-THP can also occur in brain, independent of peripheral gland secretion, in response to environmental/behavioral stimuli. The extent to which engaging in tasks related to reproductive behaviors and/or mating increased E(2) or progestin concentrations in brain was investigated. In Experiment 1, proestrous rats were randomly assigned to be tested in individual tasks, including the open field, elevated plus maze, partner preference, social interaction, or no test control, in conjunction with paced mating or no mating. Engaging in paced mating, but not other behaviors, significantly increased dihydroprogesterone (DHP) and 3alpha,5alpha-THP levels in midbrain, hippocampus, striatum, and cortex. In Experiment 2, proestrous rats were tested in the combinations of the above tasks (open field and elevated plus maze, partner preference, and social interaction) with or without paced mating. As in Experiment 1, only engaging in paced mating increased DHP and 3alpha,5alpha-THP concentrations in midbrain, hippocampus, striatum, and cortex. Thus, paced mating enhances concentrations of 5alpha-reduced progestins in brain areas associated with reproduction (midbrain), as well as exploration/anxiety (hippocampus and striatum) and social behavior (cortex).     

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.     

eFFFE纤维技术的创新：性能、应用和机会

叙述了W．L．Gore＆Associates公司ePTFE纤维的新发展：高温下的高拉伸强度、改善的耐磨性、一致的纤维直径、特定用途的密度、符合要求的表面结构、可在广泛范围内调节的弹性模量,以及能与大量填料结合的能力。应用一项待审的专利技术可能是首次制成了新型稳定化的低收缩100％PTFE织物。     

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。