氢化物发生-原子荧光光谱法同时测定纺织品中的砷和锑

湿法消化样品,断续流动-无色散氢化物发生-原子荧光光谱法同时测定纺织品中的砷,研究了酸度、KBH4浓度、仪器主要条件参数对实验结果的影响,以及硫脲 抗坏血酸混合液对干扰元素的消除作用。在经过优化的实验条件下,本方法砷和锑的精密度分别为1.69%和2.75%,检出限分别为0.5605μg·L-1和0.4670μg·L-1,方法的加标回收率在94.71%—96.85%之间,该方法能简单快速、准确的测定纺织品中砷和锑的残留量。     

L-半胱氨酸为预还原剂-氢化物发生-原子荧光光谱法测定饮用水中的锑

在L-半胱氨酸存在下,用氢化物发生-原子荧光光谱法测定饮用水中的锑.由于L-半胱氨酸的存在,改善了氢化物发生条件,增敏光谱测定信号,降低了溶液的酸度,过渡金属离子的干扰显著地得到了抑制.其回收率为91.2%-100.2%,检出限为0.35μg·L-1.     

原子荧光光谱法测定饮用水中的砷

研究了两种载流溶液浓度和还原剂溶液浓度条件下,原子荧光光谱法测定饮用水中砷的过程中仪器荧光强度值和光谱峰的变化,对仪器测量条件进行了优化.研究了不同检测条件下,待测水样中砷元素检出量的变化.结果表明,载流溶液浓度影响仪器荧光强度值的大小,还原剂溶液浓度影响光谱峰的出峰位置.盐酸和硫脲-抗坏血酸的加入影响待测水样中砷含量的测定结果.     

氢化物-原子荧光法测定锑精矿中痕量砷、汞的研究

研究了氢化物发生-原子荧光光谱测定锑精矿中痕量砷汞的分析方法,并对溶样方法及共存元素的干扰进行了研究。发现用王水溶解样品完全,砷汞溶出量最大;加入硫脲-抗坏血酸后,锑精矿中干扰元素的干扰基本消除;通过加入酒石酸抑制基体锑的水解,从而不需通过化学分离,直接测定锑精矿中的痕量砷汞,并用于实际样品的测定。方法的检出限分别为：砷0.220 ng·mL-1, 汞 0.002 ng·mL-1, 相对标准偏差(RSD% n=11)分别为1.47%和0.52%,回收率分别为94.0%～103.0%和98.7%～102.8%。方法具有快速、准确、灵敏度高等优点。     

微波灰化-氢化物发生原子荧光光谱法测定植物油中微量铅

采用微波灰化技术处理样品 ,运用断续流动 氢化物发生原子荧光光谱法测定植物油中的铅 ,探讨了微波灰化条件对铅测定的影响 ;研究了载流和样品酸度、还原剂浓度、基体改进剂以及载流流速对氢化物发生的影响。铅的线性范围为 1 0 0～ 2 0 0 μg·L-1,最低检出限为 0 31μg·L-1,相对标准偏差为 1 84 % ,回收率为 89 2 %～ 97 3%。     

氢化物发生-原子荧光光谱法同时测定纺织品中痕量砷和汞

本文以模拟汗液 (酸性、碱性 )和唾液萃取样品 ,断续流动 -无色散氢化物发生原子荧光光谱法同时测定纺织品中的微量砷、汞。研究了不同萃取介质、酸度、还原剂浓度、共存元素以及载流流速对氢化物发生的影响。方法快速、基体干扰少、灵敏度高、检出限低。本方法的线性范围为 As:1.0 0— 2 0 0 μg· L-1,Hg:0 .5 0— 2 0 μg· L-1,检出限为分别为 0 .0 3μg· L-1和 0 .0 1μg· L-1,回收率为 89.4 %— 10 0 .5 % ,精密度为 1.32 %— 5 .4 5 %。     

氢化物发生-双道原子荧光光谱法同时测定中药中不同形态的砷和锑

建立了一种氢化物发生-双道原子荧光光谱法同时测定中药中As(Ⅲ),As(Ⅴ),Sb(Ⅲ)和Sb(Ⅴ)的方法。对实验条件进行了优化,在最佳工作条件下,砷和锑的检出限分别为0.090 3和0.057 8 μg·L-1,RSD分别为2.01%和1.39%。将本法成功应用于中药样品的形态分析,As(Ⅲ)和As(Ⅴ)的回收率分别为90.8%～98.2%和89.2%～102.0%,Sb(Ⅲ)和Sb(Ⅴ)的回收率分别为89.7%～102.0% 和90.3%～110.0%。     

水浴消解-原子荧光光谱法测定土壤和沉积物中砷、汞、硒、锑和铋

建立了王水水浴消解-原子荧光光谱法测定土壤和沉积物中砷、汞、硒、锑和铋。将试样置于50 mL具塞玻璃比色管中,加入10 mL王水(1+1),于沸水浴中消解2 h,取出冷却后,超纯水定容,摇匀后取上清液待测。相比于微波消解的昂贵设备和低安全(高温高压)性,水浴消解法具有设备简单、易操作、重复性高等优点;同时由于实际样品中汞、硒和铋的含量都比较低,水浴消解后的试样能直接上机测定,可以大大地简化操作过程。重点研究了硼氢化钾浓度对检测灵敏度的影响,结果表明,相同仪器条件下,对于砷、硒、锑和铋元素,高的硼氢化钾浓度能在一定程度上提高其荧光强度;而对于汞而言,低的硼氢化钾浓度反而能增加其荧光强度,当采用0.1%硼氢化钾作为还原剂时,汞可以获得较好的检测灵敏度。通过比较不同预还原剂对测定结果的影响,验证了该方法测定样品中硒的可靠性,数据表明,该方法消解所用的盐酸量足够将Se(Ⅵ)还原成Se(Ⅳ),不仅不需要额外添加盐酸或硫脲,向样品中添加硫脲反而会使测定结果偏低很多。仪器最佳条件下,采用王水水浴消解-原子荧光光谱法测定土壤或沉积物中砷、汞、硒、锑和铋的方法检出限分别为0.008, 0.002, 0.002, 0.005和0.003 mg·kg~(-1)(取样量为0.500 0 g,定容体积为50 mL),测定下限分别为0.032, 0.008, 0.008, 0.020和0.012 mg·kg~(-1)。该方法用于测定土壤/沉积物标准样品中砷、汞、硒、锑和铋的相对误差范围分别为-3.3%～4.5%,-3.9%～15%,-20%～-7.8%,-13%～3.4%和2.2%～7.0%;该方法用于测定实际样品,相对标准偏差范围为1.3%～11%。采用水浴消解原子荧光光谱法测定土壤和沉积物中砷、汞、硒、锑和铋,具有操作简便、无需转移容器、普及性强、检出限低、精密度和准确度好等优点,分析结果满足环境监测要求。     

氢化物发生-原子荧光光谱法测定铜精矿中的砷、锑和铋

建立了氢化物发生-原子荧光光谱法同时测定铜精矿中砷、锑、铋的方法,采用了主量元素匹配法来消除基体干扰,优化了反应体系的酸度、还原剂浓度等条件进行了优化。砷、锑、铋的浓度在1—200μg·L~(-1)范围内与荧光强度呈线性关系。方法回收率为92%—101%,相对标准偏差为2.7%—5.5%。     

氢化物发生-原子荧光光谱法同时测定磷酸盐中砷和锑

采用盐酸溶解三聚磷酸钠、磷酸氢钙试样,氢化物发生-原子荧光光谱法同时测定砷和锑,对仪器条件、盐酸、预还原剂、还原剂用量、共存离子干扰进行了试验。方法的检出限砷为6.3ng·g-1,锑为6.8ng·g-1,砷的测定精密度为1.14%—5.42%,回收率为99.4%—103.5%,锑的测定精密度为1.25%—1.77%,回收率为98.0%—101.9%。     

基于L-半胱氨酸组装银纳米棒的SERS的传感器检测汞离子

以L-半胱氨酸(L-Cys)组装银纳米棒的SERS传感器检测汞离子。讨论了能捕获汞离子的标记分子的种类,选择L-Cys为标记分子,L-Cys通过S—Ag键链接在银纳米棒表面。紫外-可见吸收光谱对银纳米棒及组装上L-Cys和Hg2+分别进行表征,通过10种金属离子验证了该分子探针的对汞离子的特异性吸附,构建了“Ag-L-Cys-Hg”层状结构。标记分子-金属纳米粒子偶联物的稳定性由配体分子、温度、pH值等决定,讨论了L-Cys标记分子的浓度、pH值、温度的最佳条件,对一系列汞离子浓度进行测定,线性范围在0.01～1 μmol·L-1之间,相关系数为0.990,检出限为1 nmol·L-1。对实际水样进行了测定,加标回收率在85%～103%之间。建立了一种高效、快捷、灵敏度高、稳定性好痕量测定Hg2+的方法。     

Sol-gel preparation and enhanced photocatalytic performance of Cu-doped ZnO nanoparticles

Cu-doped ZnO nanoparticles were prepared by a sol-gel method for the first time. XRD, XPS, UV-vis and FS techniques were used to characterize the Cu-doped ZnO samples. The photocatalytic activity was tested for methyl orange degradation under UV irradiation. The results show that the crystal sizes of ZnO and 0.5% Cu/ZnO nanoparticles with wurtzite phase are 32.0 and 28.5 nm, indicating that Cu-doping hinder the growth of crystal grains. The doped Cu element existed as Cu²⁺. The optimal Cu doping concentration in ZnO is 0.5%. The optimal calcination condition is at 350 °C for 3 h. The MO degradation rate of 0.5% Cu/ZnO reaches 88.0% when initial concentration of MO is 20 mg/L, exceeding that of undoped ZnO. The enhanced charge carrier separation and increased surface hydroxyl groups due to Cu-doping contributed to the enhanced photocatalytic activity of 0.5% Cu/ZnO.     

活性炭富集电感耦合等离子体原子发射光谱测定铋系超导粉中痕量铁

建立了电感耦合等离子体原子发射光谱(ICP-AES)测定超导粉中痕量铁的新方法。优化了仪器工作参数,对痕量铁测定时的基体干扰及消除干扰的方法进行了系统研究,结果表明:大量存在的基体元素产生一定基体效应,并使重现性变差,且由于铁含量甚微,仪器灵敏度不能满足测定的要求,需采用分离富集方法以提高测定结果的准确度和精密度。以三乙醇胺掩蔽基体元素铋和铜,在适宜的酸度条件下,铁与邻二氮菲生成配合物,以活性炭定量吸附,用1∶1硝酸解吸,并对分离富集条件进行了优化。对模拟标准样品进行测定,分析结果与理论值一致,相对标准偏差为2.4%,方法检出限为0.033μg.g-1。该方法已用于超导前驱粉样品中痕量铁的分析,结果令人满意,并进行了回收实验,回收率为95.6%～98.0%。     

Optimization of regenerator based on semiconductor optical amplifier for degraded differential phase shift keying signal

Real time phase regeneration is necessary for degraded phase modulation format optical communication systems.A regenerator based on the discrimitive gain effect of a semiconductor optical amplifier was proposed in recent years.In this paper,for this type of regenerator,its optimal working condition is found by solving the dynamic equations which describe the variance of the optical field and carrier density in the semiconductor optical amplifier by the finite difference method.The results show that the optimal improvement of signal Q factor can reach more than 2.2 dB.     

半胱氨酸作为耦联剂制备的纳米银膜上的SERS研究

在直流10V电压下电解聚乙烯醇和硝酸银的混合液3h制备纳米银胶,将经过半胱氨酸修饰后的载玻片浸入银胶24h制得纳米银膜。用紫外可见分光光度计对银胶进行了观测,由于其吸收峰半高宽较窄可知银胶中纳米银颗粒粒径分布较为均匀。同时,使用扫描电镜对银膜进行了表征。通过对半胱氨酸分子SERS信号的分析得出了纳米银粒子在玻璃表面上可能的组装方式。以结晶紫(Crystal Violet)和孔雀石绿(Malachite Green)作为探测分子,采用便携式拉曼光谱仪测得两种分子不同浓度下的SERS谱。发现该方法所制得的纳米银膜有很好的表面增强效果。最后分析了半胱氨酸分子SERS信号对探针分子光谱的影响。     

Rapid preparation and characterization of chitosan nanoparticles for oligonucleotide

Chitosan is regarded as one of the potential candidates as a gene carrier. However, the poor solubility of chitosan is the major limiting factor in its utilization as a gene carrier. The purpose of this study was to simplify the method of preparing the nanoparticles of chitosan linked with antisense oligonucleotide (asON). The main step was preparing the derivatives of chitosan phosphate (CSP) in order to easily dissolve in aqueous solution. The nanoparticles were formed using a simple mixed method for CSP and asON, and the nanoparticle’s forming condition was optimized so that the nanoparticle’s characterization could be examined. Results showed that it was simple to make the nanoparticles under the optimal condition of 2:1 M proportion of CSP and asON. The size of the nanoparticles was 102.6 ± 12.0 nm, its zeta potential was 1.45 ± 1.75, and the encapsulated ratio of the chitosan crosslinked the asON was 87.6 ± 3.5%. The infrared spectra and electron microscope displayed that chitosan may combine with the asON to form equirotal nanoparticles. In conclusion, it was simple and feasible to form chitosan nanoparticles for asON using the CSP, and the CSP can efficiently encapsulate asON.     

The Effect of L-Cysteine on Surface-Enhanced Raman Scattering of Malachite Green in Silver Colloids

ABSTRACT

Colloidal silver nanoparticles were prepared by a simple chemical reduction method. The effect of L-cysteine on the surface-enhanced Raman scattering activity of colloidal silver nanoparticles was investigated by using malachite green as a probe molecule. It was found that the surface-enhanced Raman scattering activity of colloidal silver nanoparticles was improved tremendously with the help of L-cysteine. The possible reasons for this enhancement effect were given. Specifically, in silver colloidal solution, no surface-enhanced Raman scattering spectrum of malachite green was observed at a relatively low concentration (≤2.5 × 10^?5 mol/L). However, well-resolved and high-quality surface-enhanced Raman scattering spectra of malachite green were successfully obtained after the addition of L-cysteine to silver colloids, and the minimum detection limit for malachite green was down to 10^?8 mol/L.     

Controlled growth of flower-like SnS2 hierarchical structures with superior performance for lithium-ion battery applications

Ionics - Controlled growth of flower-like SnS2 hierarchical structures was obtained by a facile hydrothermal method with the mixture solution of SnCl4 and L-cysteine (L-cys). The results of...     

Revisiting perceptual compensation for effects of reverberation in speech identification

Listeners were given the task to identify the stop-consonant [t] in the test-word "stir" when the word was embedded in a carrier sentence. Reverberation was added to the test-word, but not to the carrier, and the ability to identify the [t] decreased because the amplitude modulations associated with the [t] were smeared. When a similar amount of reverberation was also added to the carrier sentence, the listeners' ability to identify the stop-consonant was restored. This phenomenon has in previous research been considered as evidence for an extrinsic compensation mechanism for reverberation in the human auditory system [Watkins (2005). J. Acoust. Soc. Am. 118, 249-262]. In the present study, the reverberant test-word was embedded in additional non-reverberant carriers, such as white noise, speech-shaped noise and amplitude modulated noise. In addition, a reference condition was included where the test-word was presented in isolation, i.e., without any carrier stimulus. In all of these conditions, the ability to identify the stop-consonant [t] was enhanced relative to the condition using the non-reverberant speech carrier. The results suggest that the non-reverberant speech carrier produces an interference effect that impedes the identification of the stop-consonant. These findings raise doubts about the existence of the compensation mechanism.