赛默飞ICE3500原子吸收分光光度计测定食品中铅元素的条件优化

建立了微波消解-石墨炉原子吸收光谱法测定酱油、茶叶、食用菌干香菇中的铅元素含量的方法。研究对比(2%磷酸二氢铵溶液)、(1%硝酸钯溶液)、(2%磷酸二氢铵+1%硝酸+1%抗坏血酸)3种基体改进剂对酱油、茶叶、食用菌干香菇中铅原子吸光度值的影响;以增加铅元素的稳定性和灵敏度为依据,优化了程序升温中灰化温度及原子化温度。最佳测定方法:采用(2%磷酸二氢铵+1%硝酸+1%抗坏血酸)作为基体改进剂,灰化温度700℃,原子化温度1200℃,用塞曼校正背景对酱油、茶叶、食用菌干香菇进行测定。     

钯-硝酸铵在石墨炉原子吸收法测定海水中铅的应用研究

建立了应用钯-硝酸铵作为基体改进剂,石墨炉原子吸收法直接进样测定海水中铅的方法;并对钯-硝酸铵是如何消除海水中高浓度盐分的基体干扰、降低背景吸收、提高灰化温度和原子化温度的作用机理和基体改进效应进行了分析探讨。在吸收波长283.3nm处,铅在0~60 ng/m L范围内符合比耳定律,相关系数γ=0.9999;RSD3%;加标回收率98.6%。方法用于测定海水中的铅,简便、快捷、准确。     

用石墨炉原子吸收光谱法测定次磷酸钠中微量铅

试样直接用水溶解,以磷酸氢二铵作测铅基体改进剂,考察了基体改进剂用量,原子化温度以及基体元素对测定的影响,在最佳测定条件下,用石墨炉原子吸收光谱法测定了次磷酸钠中微量铅,测试结果为:线性范围为0～60×10-3μg/mL,检出限为1.6×10-3μg/mL,回收率为94.0%～102.6%,RSD<5%。方法简便,灵敏度高,重现性较好。     

石墨炉原子吸收光谱法测定金银花中铅镉的研究

采用石墨炉原子吸收法(GFAAS)检测中药材金银花中微量重金属铅、镉的含量.考察了基体改进剂、灰化/原子化温度和常见共存离子等因素对测定的影响,建立以NH4H2PO4为基体改进剂石墨炉原子吸收光谱法测定金银花中微量铅、镉的方法.条件优化后的方法简便快速,重现性好,灵敏度、准确度高,铅的检出限为0.268 μg/L,镉的检出限为0.013 μg/L,回收率85%～110%.     

分光光度法测定云芝发酵浸膏中总三萜含量

采用分光光度法对云芝发酵浸膏中总三萜化合物含量进行测定。结果表明:5%香草醛-冰醋酸用量为0.3mL,高氯酸用量为0.8 mL,反应温度为70℃,反应时间为20 min,加冰醋酸5 mL,摇匀,在570 nm处测定其吸光值,效果最佳。标准曲线方程为Y=0.0092x-0.0447,R2=0.9991,吸光值与齐墩果酸含量在13μg~91μg范围内呈良好的线性关系;三萜类化合物的质量分数为0.564%,RSD=0.7%。齐墩果酸加样回收率98.60%~101.88%,平均加样回收率为99.93%,RSD为1.12%;在反应结束0~40 min内,吸光值相对稳定。该方法具有简便、快速、灵敏、重复性好。     

微波消解-石墨炉原子吸收光谱法测定蔬菜中痕量钼

建立了微波消解-石墨炉原子吸收光谱法测定蔬菜样品中的痕量钼。通过密闭高压、微波消解样品来制备样品溶液,研究了不同基体改进剂及其用量对吸光度的影响;采用氘灯背景扣除,313.3 nm作为钼的测定波长,3μL 1 g·L~(-1)磷酸二氢铵为基体改进剂,灰化温度为1000℃;原子化温度为2800℃。在该实验条件下,方法的线性范围为0~200μg·L~(-1),相关系数r=0.9997,检出限为3.6μg·L~(-1),测定样品的相对偏差为0.50~2.1%,回收率为92.8%~102.4%。该法灵敏快速,准确度高,适用于蔬菜等植物样品中痕量钼的测定。     

顶空-气相色谱法测定水中一氯苯

实验采用顶空-气相色谱法对水样的一氯苯进行分析,优化顶空的前处理条件及气相色谱条件,方法最低检测浓度可达0．005mg／L,标准曲线的线性相关系数r^2=0．9999,线性范围为0．1～2mg／L,样品平均加标回收率在101．4％～103．4％之间,相对标准偏差在1．6％～6．94％之间。该方法操作操作简单,重现性好、检出限低,适合水中一氯苯的检测。     

原子吸收光谱法测定钴溶液中的镍量

为了快速准确地测定钴溶液中镍的含量,本文通过实验,采用火焰原子吸收光谱法进行测定。在选定的最佳实验条件下,镍在0．50～2．OOug／mL范围内线性良好,其校正曲线的回归方程之相关系数均大于0．999。同时本文还系统研究了不同含量的钴基体对镍测定结果的干扰情况,当基体中钴含量大于20g／L时,对镍的测定干扰不可忽略,需要通过基体匹配方法来加以校正。该方法测定镍的检出限达0．022ug／mL,相对标准偏差为3．60-7．18％,镍的加标回收率在96．7～108．1％之间。该方法具有操作简单、重现性好、准确、快速等特点,完全满足车间对钴溶液中镍的质量控制分析需求。     

电感耦合等离子体质谱法测定高纯钴粉中杂质元素

本文建立了电感耦合等离子测定高纯钴粉中多种杂质元素含量的分析方法。考察了测量过程等离子体中形成的多原子复合离子对待测元素产生的质谱干扰、基体元素对相邻待测元素的质谱叠加干扰及基体对待测元素产生的基体效应,引入内标元素Sc、In对因基体导致的抑制效应进行有效的补偿。加标回收率达到85～105％,方法的检出限为0．01～0．5μgg^-1,相对标准偏差0．3～5．5％。本方法可以满足99．999％以上纯度金属钴粉的检测。     

用萃取光度法测定镀镍液中的微量铜

在pH值为4的条件下,以二乙基氨荒酸铅[Pb(DDTC)2]的氯仿溶液为萃取剂,用一次萃取法与镀镍液中的微量Cu2 进行交换,将Cu(DDTC)2萃取进入有机相,用分光光度法在波长436 nm处测定了镀液中的铜含量.结果表明,Cu(DDTC)2的表观摩尔吸光系数为1.16×104 L/(mol·cm),在0～3.2 μg/mL范围内吸光度与Cu2 浓度呈良好的线性关系,相关系数r=0.999 8,检出限为0.026 μg/mL,应用该方法对镀镍液样品进行测定,测定的相对标准偏差为1.6%,加标回收率为96.7%～101.9%.大量镍离子的存在对铜的测定无干扰.该方法具有较高的灵敏度、准确度与精确度,适宜于镀镍液中微量铜的现场分析.     

Dihydrogenimidazole modified silica-sulfonated poly(ether ether ketone) hybrid materials as electrolyte membranes for direct ethanol fuel cells

The present study reports on dihydrogenimidazole modified inorganic-organic mixed matrix membranes for possible application as a proton exchange membrane in direct ethanol fuel cells. The polymeric phase consisted mainly of sulfonated poly(ether ether ketone) (sPEEK) with a sulfonation degree of 55%. The inorganic phase was built up from hydrophilic fumed silica particles interconnected with partially hydrolyzed and condensed tetraethoxysilane with a total inorganic loading of 27.3%. This inorganic phase was further modified with N-(3-triethoxysilylpropyl)-4,5-dihydroimidazole (DHIM), which consists of an hydrolyzable inorganic part and a functional organic group. The influence of the modifier on the mixed matrix system was studied by means of various modifier concentrations in various aqueous-ethanolic systems (water, 2 M and 4 M ethanol). Modifier concentration and ethanol concentration of the ethanol-water mixture exhibited significant but opposite effects on the liquid uptake of the mixed matrix membranes. The proton conductivity as well as the proton diffusion coefficient as a function of modifier content showed a linear decrease. The proton conductivity as a function of temperature showed Arrhenius behavior and the activation energy of the mixed matrix membranes was 43.9 ± 2.6 kJ mol⁻¹. High selectivity of proton diffusion coefficient to ethanol permeability coefficient was obtained with high modifier concentrations. At low modifier concentrations, this selectivity was dominated by ethanol permeation and at high modifier concentrations by proton diffusion. The main electrolyte properties can be optimized by setting the DHIM content in mixed matrix membrane. With this approach, tailor-made membranes can be prepared for possible application in direct ethanol fuel cells.     

表面改性剂对碳酸钙基复合白色颜料性能影响研究

本文通过活化一复合两步法制备碳酸钙基复合白色颜料粉体。研究了不同表面改性剂对颜料性能的影响,并且测试了复合粉体的遮盖力、吸油值、白度等性能及微观形貌。结果表明选取三乙醇胺为改性剂时,复合粉体的综合性能最佳,其中遮盖力为19．5g／m2,吸油值24．2g／100g,白度95．8％。     

超细碳酸钙填充型粉末NR的研究

以NR胶乳为原料，超细碳酸钙为填料，高分子树脂为包覆剂兼超细碳酸钙表面改性剂，用凝聚共沉法制备填充型粉末NR。研究了产物粒径及其硫化胶力学性能的影响因素。结果表明，当包覆剂的用量为20质量份时，超细碳酸钙表面改性剂用量为4－5质量份，超细碳酸钙填充量为100－175质量份，可获得粒径≤0.9mm的超细碳酸钙填充型粉末NR达94．5％以上；超细碳酸钙填充量为25－200质量份的范围内，其硫化胶具有优良的力学性能，并显著优于块状NR／超细碳酸钙通过机械混烧所得到的硫化胶，扫描电镜分析显示超细碳酸钙以原生粒子均匀分数于NR基体中，二者形成的界面结合牢固。     

Tailoring impact toughness of poly(L-lactide)/poly(ε-caprolactone) (PLLA/PCL) blends by controlling crystallization of PLLA matrix

Melt blending poly(L-lactide) (PLLA) with various biodegradable polymers has been thought to be the most economic and effective route to toughen PLLA without compromising its biodegradability. Unfortunately, only very limited improvement in notched impact toughness can be achieved, although most of these blends show significant enhancement in tensile toughness. In this work, biodegradable poly(ε-caprolactone) (PCL) was used as an impact modifier to toughen PLLA and a nucleating agent was utilized to tailor the crystallization of PLLA matrix. Depending on the nucleating agent concentrations in the matrix and mold temperatures in injection molding, PLLA/PCL blends with a wide range of matrix crystallinity (10-50%) were prepared by practical injection molding. The results show that there is a linear relationship between PLLA matrix crystallinity and impact toughness. With the increase in PLLA crystalline content, toughening becomes much easier to achieve. PLLA crystals are believed to provide a path for the propagation of shear yielding needed for effective impact energy absorption, and then, excellent toughening effect can be obtained when these crystals percolate through the whole matrix. This investigation provides not only a new route to prepare sustainable PLLA products with good impact toughness but also a fresh insight into the importance of matrix crystallization in the toughening of semicrystalline polymers with a flexible polymer.     

基于pH响应的氨传感器的研究

本文研究利用二甲基二甲氧基硅烷(DiMe-DMOS)和正硅酸甲酯(TMOS)掺杂,获得具有好柔韧和透明性的基质材料,并利用该材料对pH指示剂溴酚蓝(BPhB)、溴百里酚蓝(BCB)进行包埋。所获得的敏感膜对水体中的氨浓度的响应范围为0～20μg/mL,响应时间为5min。     

The influence of different alkaline earth oxides on the structural and optical properties of undoped,Ce-doped,Sm-doped,and Sm/Ce co-doped lithium alumino-phosphate glasses

Undoped, singly Sm doped, Ce doped, and Sm/Ce co-doped lithium alumino-phosphate glasses with different alkaline earth modifiers were prepared by melt quenching. The structure of the prepared glasses was investigated by FT-IR and Raman, as well as by optical spectroscopy. The effect of the optical basicity of the host glass matrix on the added active dopants was studied, as was the effect doping had on the phosphate structural units. The optical edge shifts toward higher wavelengths with an increase in the optical basicity due to the increased polarizability of the glass matrix, but also with increasing CeO₂ concentration as a result of Ce³⁺/Ce⁴⁺ inter valence charge transfer (IV-CT) absorption. The optical band gap for direct and indirect allowed transitions was calculated for the undoped glasses. The glass sample containing Mg²⁺ modifier ions is found to have the highest value (4.16 eV) for the optical band gap while Ba²⁺ has the lowest value (3.61 eV). The change in the optical band gap arises from the structural changes and the overall polarizability (optical basicity). Refractive index, molar refractivity R_m and molar polarizability α_m values increase with increasing optical basicity of the glasses. The characteristic absorption peaks of Sm³⁺ were also investigated. For Sm/Ce co-doped glasses, especially at high concentration of CeO₂, the absorption of Ce³⁺ hinders the high energy absorption of Sm³⁺ and this effect becomes more obvious with increasing optical basicity.     

分光光度法测定铜合金中微量钼

抗坏血酸—硫氰酸盐分光光度法较为广泛的应用于钼的测定,是灵敏度和相对稳定性较好的测定钼的一种方法。本文以铜盐作催化剂,用硫脲消除基体铜的干扰,用抗坏血酸作还原剂,使5价钼与硫氰酸盐形成橙色络合物,借此作为钼的光度法测定。此络合物的最大吸收波长为460 nm,钼的浓度0～4.0 mg/L 范围内有良好的线性关系。方法用于铜合金中钼的测定,相对标准偏差小于2%     

原子吸收光谱法测定有机锗(Ge-132)中的锗及其杂质

用火焰原子吸收法测定了有机锗(Ge-132)中的锗,线性浓度范围为0～1.25毫克/毫升,相对标准偏差<2%,平均回收率为99.5%。用塞曼石墨炉原子吸收法测定杂质 Pb 和 As,测Pb 时用(NH_4)_2HPO_4+Mg 作改进剂,测 As 时用 Pd 作改进剂,特征质量分别为8.2pg 和8pg,相对标准偏差分别为2.1%和2.2%,还讨论了有关机理问题。     

用AIR-C2H2原子吸收光谱法测定镉镍电池正极浸渍液中钴含量

本文主要简述与运用AIR-C2H2原子吸收光谱法进行镉镍电池正极浸渍液中钴含量的测定，介绍了钴最佳测定条件及呈良好线性范围的浓度。同时对样品消化处理条件，在测定中样品的干扰因素进行了综合考虑，该方法具有很好的灵敏度，很好的重复性，干扰小，同时具有方法步骤简单，操作容易掌握等特点，对样品钴含量的测定，其相对标准偏差均小于1.0%（n=6），标准加入回收率均在97.0%～102.0%(n=5）范围内，结果表明，运用AIR-C2H2原子吸收光谱法测定镉镍电池正极浸渍液中钴含量的分析，达到了实验室分析质量控制的要求，完全适用于镉镍电池正极浸渍液中钴含量的控制分析和样品系统分析。     

核／壳结构聚合物改性硬质聚氯乙烯的力学性能

采用种子乳液聚合制备了丙烯酸酯核/壳结构聚合物,总转化率超过95%,乳胶粒理论粒径与实测值基本一致,说明聚合体系没有明显的二次成核过程.将其用于硬质聚氯乙烯改性,当加入量为3 phr时,就能产生显著的增韧效果,常温缺口冲击强度达到16.51 kJ/cm2,而拉伸强度基本保持不变.扫描电镜分析冲击断口表明,核/壳聚合物已经很好分散到聚氯乙烯基体中,呈网状结构,为明显的韧性断裂过程.该研究有望应用于工业生产.