《饰品 有害元素限量的规定》等四项国标通过审议

不久前,在莆田召开的2008年度全国首饰标准化技术委员会年会上,审议并通过了饰品四项国家标准:《饰品有害元素》、《饰品六价铬的测定二苯碳酰二肼分光光度法》、《饰品有害元素的测定光谱法》及《金合金首饰金含量的测定重量法》。《饰品 有害元素限量的规定》等四项国标通过审议@志     

考察不同组成及制备工艺对合金饰品镍释放量的影响

镍被广泛应用于日常使用的合金饰品中,镍的释放会引起皮炎等症状.针对不同组成及制备工艺的合金饰品进行了镍释放量的考察,表明相同基材的合金饰品,随着镍含量的增加,镍释放量增加;相同镍含量的基材,应用冲压工艺制备样品的镍释放量值低于失蜡浇铸工艺制备样品的镍释放量值.贵金属的加入能有效抑制镍释放量.     

瑞典化学品管理局抽查发现儿童珠宝及玩具产品存在铅镉含量超标

瑞典化学品管理局对该国两间商场的玩具以及儿童首饰进行抽检,发现存在铅、镉、镍元素含量超标的情况。在29款被抽查的儿童首饰中,7款产品被检出镉、镍含量超标;3款产品镍元素释放量超标;4款产品镉含量超标。此外,12款在售产品虽在目前仍符合铅含量的要求,但是根据将在2013年10月9日正式生效的欧盟法规要求,也将存在铅超标的风险。     

气相色谱-质谱联用法研究泡沫塑料中易挥发组分在环境温度下的释放行为

用气相色谱-质谱(GC-MS)联用技术研究了泡沫塑料中易挥发组分在不同环境温度下的释放行为.试验发现:泡沫塑料在一定温度下可释放出近20种化合物,其中绝大多数是带苯环的有毒有害化合物.温度对泡沫塑料中易挥发组分的逸出有着显著性影响,特别是在60℃以上.释放量随放置时间的增加而缓慢增加,在一定温度下存在着一个平衡.泡沫塑料中易挥发组分的释放量随着塑料用量的增加而增加,而温度是影响释放量的最主要因素.     

滤棒中线纤维化学特性对卷烟主流烟气有害成分释放量的影响

为了研究中线滤棒中线纤维化学特性对卷烟主流烟气中有害成分释放量的影响,采用Boehm滴定法及FT-IR光谱对纤维的基团及数量进行了分析,并结合烟气常规以及主流烟气有害成分释放量的检测探讨了纤维的化学特性与主流烟气有害成分释放量之间的相关性。结果显示：（1）卷烟主流烟气中NH。释放量随着纤维酸性基团数量的增加而降低;HCN释放量随着纤维碱性基团数量的增加而降低;（2）影响苯酚释放量的主要因素是纤维的内酯基,其次是纤维的酸碱性;（3）卷烟主流烟气中巴豆醛的释放量随纤维的氨基基团数量的增加而降低。     

火焰原子吸收光谱法测定金属纽扣中的镍释放量

应用火焰原子吸收光谱法测定了金属纽扣中镍的释放量。样品用旋转磨损试验机进行磨损实验,然后用人工汗液进行浸泡。前处理以后,取处理溶液进行火焰原子吸收光谱法分析,标准曲线用镍元素的标准溶液制作。在此基础上用标准加入法作了回收实验,测得镍元素的回收率在95.0%~106.5%之间。     

仿真饰品中镍释放量测定能力验证的组织与实施

为了了解我国仿真饰品中镍释放量检测能力的整体水平,中国国家认证认可监督管理委员会(CNCA)组织了"CNCA–12–B07仿真饰品中镍释放量的测定"能力验证项目,该项目共有来自12个省市、特别行政区的38家实验室参加。镍释放量主要采用GB/T 19719–2005与EN 1811:2011进行检测,对检测结果采用稳健(Robust)统计方法分析。结果显示,第1次测试结果合格率为89.5%。     

原子吸收光谱法测定首饰镍释放量的不确定度评定

通过对原子吸收光谱法（AAS）测定首饰中镍释放量不确定度的评定,建立了该分析过程的相应数学模型,对数学模型中各个参数进行不确定度来源分析。研究结果表明:配制标准液以及标准工作曲线拟合线性方程是不确定度的主要来源。通过计算,首饰中镍释放量的合成标准不确定度为3.02×10-3,当包含因子k=2,置信水平为95%时,扩展不确定度为 6.04×10-3 μg/(cm2·week）。     

电感耦合等离子体发射光谱(ICP-AES)法测定铂金材料中杂质元素

建立了微波消解-电感耦合等离子体原子发射光谱(ICP-AES)法同时测定铂饰品国家标准物质中金、铜、铱、钴、钯、铑、钌7种杂质元素含量的方法.方法中7种元素的检出限为:钯与钌＜0.0001％,其它元素＜0.00062％.经与国家标准物质认定值比对,结果满意.稀释系数95.5％～104.7％.方法测定结果与标准样品认定值一致,可满足铂金材料中杂质元素检测.     

聚甲基丙烯酸甲酯/聚甲基丙烯酸-2-羟乙酯复合微球的合成及药物吸放性能

采用在甲基丙烯酸甲酯（MMA）悬浮聚合过程中滴加甲基丙烯酸-2-羟乙酯（HEMA）乳液聚合组分的悬浮-乳液耦合聚合方法,制备了大粒径聚甲基丙烯酸甲酯／聚甲基丙烯酸-2-羟乙酯（PMMA／PHEMA）复合微球。PMMA／PHEMA复合微球表面以HEMA乳液聚合物为主,且具有微孔结构。PMMA／PHEMA复合微球在水和苄醇中的平衡溶胀率大于PMMA微球。PMMA／PHEMA复合微球48h异丁苯丙酸负载百分比为35．6％,PMMA为27．6％。在磷酸盐缓冲液中释放时间达到360h,释放量占负载总量的82％;而PMMA微球的释放时间为216h,释放量仅占负载总量的60％。     

用ICP-AES法测定首饰金的成分

本文报道采用ICP-AES法直接同时测定首饰金中合金无素及主要杂质元素含量,通过计算求得金含量。确定了仪器的最佳工作条件,进行了干扰试验。方法适用于18k～99.99%成色的首饰金。测定的RSD为<0.01%(对于高纯度金祥n=10)～0.2%(对于10k金样n=10)之间,分析结果表明,方法准确、快速、简便且样品消耗量少。     

Agreement between diary records of time spent outdoors and personal ultraviolet radiation dose measurements

Little is known about the validity of self-recorded sun exposure and time spent outdoors for epidemiological research. The aims of the current study were to assess how well participants' self-recorded time outdoors compared to objective measurements of personal UVR doses. We enrolled 124 volunteers aged 40 and above who were identified from targeted subgroups of US radiologic technologists. Each volunteer was instructed to wear a polysulfone (PS) dosimeter to measure UVR on their left shoulder and to complete a daily activity diary, listing all activities undertaken in each 30 min interval between 9:00 A.M. and 5:00 P.M. during a 7 day period. In a linear regression model, self-recorded daily time spent outdoors was associated with an increase of 8.2% (95% CI: 7.3-9.2%) in the personal UVR exposure with every hour spent outdoors. The amount of self-recorded total daily time spent outdoors was better correlated with the personal daily UVR dose for activities conducted near noon time compared to activities conducted in the morning or late afternoon, and for activities often performed in the sun (e.g. gardening or recreation activities) compared to other outdoor activities (e.g. driving) in which the participant is usually shaded from the sun. Our results demonstrated a significant correlation between diary records of time spent outdoors with objective personal UVR dose measurements.     

氢化物发生-原子荧光光谱法测定仿真饰品中可萃取砷锑汞硒

模拟人体皮肤环境,采用酸性汗液处理样品,通过氢化物发生-原子荧光光谱法测定仿真饰品中可萃取砷、锑、汞和硒.优化了实验条件,研究了共存离子的干扰.砷、锑、汞和硒的检出限分别为0.044,0.011,0.003,0.041 μg/L.采用该法对仿真饰品进行测定,测定结果的相对标准偏差为2.9%-9.1% (n=3),回收率...     

Enhanced flow injection leaching of rocks by focused microwave heating with in-line monitoring of released elements by inductively coupled plasma mass spectrometry

A focused microwave digestion system was used to heat a mini-column of sample of crushed rock (hematite) during its successive leaching by repeated 250-μL injections of water, HNO₃ 1%, 10% and 30% (v/v). The mini-column was connected to the nebulizer of an inductively coupled plasma mass spectrometry instrument, which allowed a continuous monitoring of the progressive release of elements by a given leaching reagent. Quantitation of the accessible fraction of Mg, V, Cr, Mn, Co, Ni, Cu, Zn, Mo, Sb and Pb was done by calibration using 250-μL injections of standard solutions prepared in the leaching reagent matrices. Total digestion of the sample residue was also done to verify mass balance. With the exception of Mg, V and Co, where the same total amount was released with or without microwave heating, an increased release resulted from focused microwave heating, by up to an order of magnitude. Furthermore, mass balance was verified for more elements using microwave heating, presumably because of a lower relative proportion of spectroscopic interference as a result of an increased release of analytes. Using microwave energy in general resulted in the dissolution of additional phases, as evidenced by significantly different ²⁰⁸Pb/²⁰⁶Pb ratios as well as the increased release of elements with milder reagents. In fact, in the case of Pb, leaching with 30% HNO₃ was no longer necessary as all the Pb was released in the first three leaching reagents. Microwave heating could therefore be used advantageously in on-line leaching for exploration geochemistry and environmental monitoring.     

Assessment of environmental contamination risk by Pt, Rh and Pd from automobile catalyst

The main active components of present-day car catalysts are the noble metals Pt, Pd and Rh, belonging to the platinum group elements (PGEs). It is recognized that these elements are being spread into the environment to an as-yet incompletely known extent, mainly due to surface abrasion of the catalyst during car operation. These new pollutants have motivated extensive research on PGE determination. Our work is planned to ascertain the health and ecosystem risks of these PGEs emitted through a series of interrelated objectives that address the pathway of these elements from the catalyst to the different environmental compartments. Combined studies of catalyst surface abrasion and exhaust fumes analysis, the monitoring of Pt, Pd and Rh in airborne particles and road dust sediments and bioaccumulation studies in aquatic organisms, plants and urine enable a realistic assessment of the risk that this release represents for man and environment. In this work some previous results are presented.     

Research on high temperature friction properties of PTFE/Fluorosilicone rubber/silicone rubber

Silicone rubber (MVQ) has excellent heat resistance, but poor high temperature friction stability, which limits its application in the field of high temperature sealing. Polytetrafluoroethylene (PTFE) is self-lubricating, but its compatibility with rubber is relatively weak. In order to improve the high-temperature friction property of silicone rubber, fluorosilicone rubber (FVMQ) was used as a compatibilizer, and PTFE was added to MVQ by mechanical blending. The friction and wear properties of PTFE/FVMQ/MVQ composites at different temperatures were studied. The results show that compared with MVQ, the mechanical properties of PTFE/FVMQ/MVQ composites was basically unchanged, the coefficient of friction was hardly affected by temperature, and the amount of wear decreased with increasing temperature. PTFE/FVMQ/MVQ composites showed excellent high-temperature abrasion resistance. The high-temperature wear mode was mainly changed from abrasive wear to adhesive wear. The molten layer formed by high-temperature friction can prevent air from directly contacting the surface rubber, which inhibited rubber surface oxidation reaction process.     

Experimental method for wear assessment of sealing elastomers

Elastomeric dynamic seals are components to prevent or to limit lubricant leakage in machinery. Nevertheless, they wear away under certain working conditions. Mostly, wear exists by starvation of lubricant film (two-body abrasion) and interaction with hard debris (three-body abrasion). This work aims to propose a suitable test methodology toward determining two-body and three-body abrasive wear rates of elastomers by using a TE66 Micro-Scale Abrasion Tester. In the tests, sections of silicone rubber were used. The experiments were divided in two parts. Firstly, dry runs were carried out replicating the two–body abrasion mechanism. Secondly, trials were run using two different media (contaminated oil and slurry) to reproduce three-body abrasive wear. Large viscoelastic deformations were generated in the samples and then they were considered for the wear estimation. In conclusion, the method shows advantages which make it suitable as an alternative test to obtain the wear behavior of sealing elastomers.     

Trace element analysis of motor oil by CPAA method on external proton beam

Normal motor-oil was investigated by CPAA method using 12 and 18 MeV proton beams, which were extracted to the air. The samples were taken from the oil carter of a motor after different running times. The change of the amount of certain trace elements was detected with increasing time of use. By using this method the friction wear of the engine material can also be measured.     

磺化石墨烯/天然橡胶复合材料的性能研究

以磺化石墨烯为填料,将其填充到天然胶乳中,混合均匀后共沉淀,采用传统橡胶加工方法制备了天然橡胶复合材料。对磺化石墨烯的结构和形貌进行了表征,测定了硫化胶的力学性能、耐磨性能、透气性能和导热性能。研究结果表明:磺化石墨烯表面含有丰富的活性官能团,为少层片状结构,硫化胶的力学性能、耐磨性得到了提高,而透气性和导热性有所下降。当石墨烯添加量为2.0%(wt)时,复合材料的拉伸强度最大为27.06MPa;磨耗体积仅为0.08cm~3;导热系数最小为0.42W/(m·K);透气量最低,为1.98×10~(-4)cm~3/(m~2·d·Pa)。