X射线衍射法测定滑石粉中石棉成分

使用X射线衍射法,通过石棉的2θ特征峰进行判断,分析滑石粉中可能存在的石棉成分。结果表明,样品中不含温石棉、铁石棉和青石棉,并对温石棉和绿泥石进行了有效区分。方法快速,灵敏,可有效用于滑石粉中石棉的测定。     

X-射线衍射内标法定量滑石粉中的温石棉

对比α-氧化铝、氧化镁、硅粉三者的结晶属性,选择晶相良好且与温石棉特征峰无重叠的单质硅为内标物,建立温石棉衍射吸收标准曲线,该曲线在温石棉含量0%～9.3%具有较好的回归性。使用曲线分析已知温石棉含量的分析样品,测得温石棉含量为1.70%,与理论值(温石棉添加量:1.68%)的相对误差RE为0.99%。分析该方法检出限与定量限分别为0.10%和0.30%。与以金属基底建立曲线的石棉定量方法相比,内标法有较好灵敏度和准确度,是一种准确可靠的石棉定量方法。     

四苯硼钠-季铵盐容量法快速测定造纸法再造烟叶中的钾含量

采用四苯硼钠-季铵盐容量法对造纸法再造烟叶中的钾含量进行了检测.通过精密度试验和加标回收试验对方法的重复性和回收率进行了考察,结果表明:该检测方法具有较好的重复性,相对标准偏差为1.7%(n=6),回收率达到99.14%.该法和流动分析仪(AA3)的检测结果对比表明两种方法的检测结果具有较好的一致性.该研究对造纸法再造...     

用红外光谱法定量测定滑石粉中的石棉含量

本文提出了用红外光谱法定量测定滑石粉中的石棉含量,并通过模拟样品试验认为,该法操作简单快速,结果直观可靠,适用于测定滑石粉中的石棉含量。     

使用SEM/EDS快速鉴别建筑材料和保温材料制品中的石棉

建立了一种使用扫描电镜和能谱联用鉴别建筑材料、保温材料等制品中石棉的方法。先用扫描电镜对比了六种石棉标准品的形貌特征,再对照标准品的能谱结果,证明可以通过钙、镁、硅三种元素的含量鉴别石棉种类。用该方法对待测样品中纤维物质进行分析,结果显示纤维中含有钙、镁、硅三种主要元素,其摩尔比与阳起石和透闪石的化学组成吻合,由此判断样品中含有这两种石棉。     

有机酸分析的柱后缓冲电导法与紫外法、直接电导法的比较

柱后缓冲电导法采用柱后调节pH值,电导检测器检测的方法检测有机酸,它避免了经常使用的紫外法选择性差,直接电导法灵敏度低的缺点,是可以实现有机酸准确定量的一种新型分析方法.本文比较了这三种方法的分析结果.     

液相色谱法和淀粉-碘化镉法检测聚合物含量的对比

考察了液相色谱法检测聚合物含量以及聚合物分子量对测试准确性的影响,并对比了液相色谱法和经典的淀粉-碘化镉法检测结果的差异.利用液相色谱法可对干扰多、偏差大的油井产出液中聚合物含量进行准确测定.对于其它不同介质中聚合物含量的检测有一定的应用价值.     

固体进样-石墨炉原子吸收法测定农产品中重金属元素含量

采用直接固体进样-石墨炉原子吸收光谱法(SS-GFAAS)测定农产品中镉、铅、铜和铬重金属元素含量.通过标准物质、质控样品和电感耦合等离子体质谱法比对试验验证,各元素方法检出限均低于25 pg.方法操作简单、对环境友好、重复性好、结果准确、检出限低,满足农产品检测要求.     

微波消解-ICP-OES法同时测定化妆品中Pb、As、Hg

采用微波消解ICP-OES法同时测定化妆品中Pb、As、Hg的含量,并对ICP-OES法测定化妆品消解液时分析线的选择,入射功率、泵速的影响,以及进行检测限、准确度、精密度的研究.用微波消解ICP-OES法测试化妆品中重金属检测结果快速准确.     

非水毛细管电泳法区分蓝色圆珠笔油墨的研究

建立了一种基于非水毛细管电泳法区分蓝色圆珠笔油墨的方法.确定了笔迹中碱性染料(结晶紫、甲基紫、碱性品蓝、罗丹明6G、碱性艳蓝B和碱性艳蓝BO)的分离条件:缓冲溶液为1.00 mmol/L醋酸-100 mmol/L醋酸铵的甲醇-水(体积比90 ∶ 10)体系,分离电压和温度分别为25 kV和25 ℃,检测波长为214 nm.通过该方法分析了96支蓝色圆珠笔中的油墨,并依据油墨中所含的染料种类对圆珠笔进行分类,同一类笔又通过聚类分析计量学方法再次进行区分.该法重复性好,结果准确可靠,为圆珠笔字迹鉴定提供了一种科学的方法.     

纳氏试剂测定水中氨氮影响因素的探讨

对国家生活饮用水标准检验方法"GB/T5750—2006"中涉及到的水中氨氮的检测条件进行了探讨,讨论了样品的采集与保存,影响显色、空白值的各项因素,并提出相应的解决办法。对国家标准物质以及实际样品的验证表明,方法的相对误差为0.03%~1.5%,相对标准偏差RSD为0.55%~5.3%,准确度也能满足分析要求,对国家标准方法进行了补充与细化,在实际工作中有参考价值。     

The effect of fiber coating on the tensile properties of ionomer-based composites

Asbestos fibers, of the chrysotile variety, were coated with a thin polyamide film by an in situ polycondensation technique. Ionomer-based composites were prepared containing the so-modified asbestos fibers in a random in-plane orientation; results of testing the tensile properties of these asbestos/polyamide/ionomer composites are presented. Parameters investigated comprise the asbestos content in the composite and the polyamide content deposited on asbestos. A significant improvement in the tensile performance was established, especially at the intermediate polyamide content of 3.4 phr. The behavior is discussed in terms of possible interactions between the phases present in the composite material.     

Thermal behaviour of teflon/phenolic liners in self-lubricating bearings

The gun system of the M1 series tank rides on a pair of self-aligning spherical bearings that allows the elevation and depression of the cannon. Because these bearings are encapsulated within the rotor housing, periodic lubrication or maintenance is impossible. To overcome this problem self-lubricating bearings were incorporated into the system. There are two basic liner designs, molded and fabric. Molded liners are produced by applying a formulation of teflon and typically asbestos into a phenolic resin, which is applied to the bearing surface, then cured. Fabric liners utilize a woven fabric bonded to the bearing surface, then teflon which is mixed into phenolic resin is applied to the bearing surface and cured. Initial studies of the existing bearing liner were completed to determine the liner composition and establish a baseline or standard to compare thermal and mechanical properties with potential vendors. DSC revealed an average teflon content of 39.53%, which varied significantly throughout the liner. TG analysis showed an asbestos concentration of 12.22%. The remainder of the liner was phenolic resin. Physical testing of the bearing from ?20 to 120?C under normal loading conditions demonstrated excellent thermal stability with little wear. Bearings from each vendor were tested and compared to the standard properties of the baseline bearing. Some properties were difficult to compare or insignificant due to the design differences between molded and fabric liners. The testing program resulted in the qualification of two bearings, which met or exceeded the established standards. Both of these bearings were designed with fabric liners.     

高温热水解-离子色谱法测定铬矿中氟含量

建立了一种快速、准确的离子色谱法测定铬矿中氟含量的方法,将铬矿与石英砂混合,控制氧气和水蒸气的流量,于1 100℃高温下热水解30min,水解液经吸收后,选用Dionex AS11-HC阴离子分析柱,以KOH(20mmol/L)作淋洗液,自动再生抑制型电导检测器检测,离子色谱法测定铬矿中氟的含量。方法的检出限为0.022μg/mL,定量限为0.073μg/mL,方法的检测范围为0.0015%~0.20%,加标回收率在92%~101%。应用于实际样品的测定结果表明,铬矿中氟含量的测定值与标准方法的测定值一致。方法简单快速、检出限低、精密度高、准确度好。能满足铬矿中氟含量的快速准确检测要求。     

Sound transmission testing of polymer compounds

Acoustic properties of polymer compounds are an important consideration for many applications. Currently, there are standard test methods for the determination of these properties. There is, however, no standard for the equipment used in these tests, only a specification for the test conditions. The objective of this work was to evaluate the operation and performance of a bench top laboratory sound testing system for its potential as a simple cost effective method for the initial evaluation of materials that require specific acoustic properties. The work was limited to an investigation of the property of sound transmission loss (STL). A study of the effect of the mounting conditions for the samples on the STL was carried out. Following this, a series of polymer and polymer composite samples was tested. The results presented demonstrate the potential for the testing system as an effective standard test method for the acoustic properties of polymer composites and other materials.     

Competitive adsorption of sodium dodecyl sulfate and polyethylene oxide at the air/water interface

Geoinspired synthetic chrysotile, which represents an ideal asbestos reference standard, has been utilized to investigate homomolecular exchange of bovine serum albumin (BSA), the major plasma protein, between the adsorbed and dissolved state at the interface between asbestos fibers and biological medium. FTIR spectroscopy has been used to quantify BSA structural modifications due to surface adhesion on chrysotile fibers as a function of the surface coating extent. Circular dichroism spectroscopy has been used to investigate the adsorption/desorption equilibrium through analysis of the BSA structural perturbations after protein desorption from chrysotile surface. Data results show clearly that in the solid state BSA modifications are driven by surface interaction with the substrate, following a bimodal adsorption evidenced by two different binding constants. On the other hand, BSA desorbed in solution is able to rearrange, in the lack of substrate, although keeping irreversible modifications with respect to the native species. The lack of regaining its native structure certainly affects albumin interaction with biological environment. The present investigation on the stoichiometric synthetic geoinspired chrysotile nanocrystals is the first approach toward a deeper attempt to use standard synthetic chrysotile reference samples in mimicking the behavior of asbestos fibers and allows to better understand their interaction with a biological environment.     

王水消解-冷原子吸收光谱法测定土壤中汞

为了寻求一种更加适宜测定土壤中汞含量的测试方法,将检出限低、精密度高的冷原子吸收光谱法与便捷、高效的王水水浴消解土壤处理方式相结合,建立了王水消解-冷原子吸收光谱法测定土壤中汞。通过测定方法的线性相关性、方法检出限、准确度、精密度、加标回收率,并与原子荧光光谱法进行对比实验来评价该方法的有效性。王水消解-冷原子吸收光谱法在汞质量浓度0.0~1.0μg/L范围内线性良好,相关系数可以达到0.9999,方法检出限为0.00075 mg/kg,土壤标准样品测试的相对标准偏差为4.0%~10.7%,实际样品加标回收率分别为93%~104%。采用原子荧光光谱法进行对比测试,原子荧光光谱法的方法检出限为0.0025 mg/kg,相对标准偏差为4.8%~13.5%,加标回收率为104%~107%。结果表明,对于王水水浴消解土壤的方法不仅适用于原子荧光光谱法测定汞含量,同样可以应用于冷原子吸收光谱法中。所建立的王水消解-冷原子吸收光谱法具有更低的检出限,更优的准确度和精密度,有利于提高土壤样品测试的工作效率,值得推广。     

王水消解-冷原子吸收光谱法测定土壤中汞

为了寻求一种更加适宜测定土壤中汞含量的测试方法,将检出限低、精密度高的冷原子吸收光谱法与便捷、高效的王水水浴消解土壤处理方式相结合,建立了王水消解-冷原子吸收光谱法测定土壤中汞。通过测定方法的线性相关性、方法检出限、准确度、精密度、加标回收率,并与原子荧光光谱法进行对比实验来评价该方法的有效性。王水消解-冷原子吸收光谱法在汞质量浓度0.0～1.0μg/L范围内线性良好,相关系数可以达到0.999 9,方法检出限为0.000 75mg/kg,土壤标准样品测试的相对标准偏差为4.0%～10.7%,实际样品加标回收率分别为93%～104%。采用原子荧光光谱法进行对比测试,原子荧光光谱法的方法检出限为0.002 5 mg/kg,相对标准偏差为4.8%～13.5%,加标回收率为104%～107%。结果表明,对于王水水浴消解土壤的方法不仅适用于原子荧光光谱法测定汞含量,同样可以应用于冷原子吸收光谱法中。所建立的王水消解-冷原子吸收光谱法具有更低的检出限,更优的准确度和精密度,有利于提高土壤样品测试的工作效率,值得推广。     

微波消解-电感耦合等离子体质谱(ICP-MS)法测定土壤七种金属元素

实验室比对盲样测定是检验实验室能力验证、实验室资质认定、机构考核的主要手段。为研究并解决测试实验室比对土壤盲样中铍、钒、镍、铜、锌、镉、铅的含量,采用微波消解电感耦合等离子体质谱(ICP-MS)法对土壤盲样进行研究,探讨了不同消解酸体系,检出限和定量限、测试模式和干扰消除、精密度和加标回收率、质控样品进行研究。结果表明：用6 mL HNO3,2 mL HCl和1 mL HF为混合酸体系,各待测元素标准曲线相关系数大于0.9995,检出限在0.001~2.985 mg.L-1^,定量限在0.003~9.94 mg.L-1^,采用氦气碰撞模式测试钒、镍、铜、锌、镉和铅,可以有效的降低多原子离子的干扰;采用no gas模式测试铍,可以有效的提高铍的测试灵敏度。方法精密度为0.2%~6.2%(n=6),加标回收率为92.3%~110.6%,采用土壤标准样品(GSS-4)进行全过程质控研究分析,各元素结果均在标准值参考范围内。用ICP-OES法测试土壤盲样中七种待测金属元素含量与用铑为内标的ICP-MS进行比对,测量分析结果基本一致。     

Interaction of bovine serum albumin with chrysotile: spectroscopic and morphological studies

The biodurability of chrysotile fibers, which is related to their cytotoxicity and mutagenic responses, is strongly affected by the surface chemical adsorption of biological molecules. Natural chrysotile is a heterogeneous material in both structure and composition. The availability of synthetic stoichiometric chrysotile of constant structure and uniform morphology has allowed us to investigate its interaction with bovine serum albumin (BSA). By using transmission electron microscopy (TEM) and atomic force microscopy (AFM), we have obtained the first morphological evidence of albumin adsorption onto chrysotile nanocrystals. FTIR spectroscopy was used to quantify modifications of BSA secondary structure that were induced by the surface interaction. The protein transition to beta-turns allows a stronger interaction between the protein hydrophilic side-chains and the charged asbestos surface, which is consistent with hydrogen bonds involving the superficial OH groups. Synthetic stoichiometric chrysotile nanocrystals were shown to be an ideal reference standard with which to study the interaction of asbestos fibers with biological systems, in order to elucidate the chemical mechanisms of asbestos toxicity.