火焰原子吸收光谱法测定铼产品中的痕量钠

建立了火焰原子吸收光谱法测定高铼酸、高铼酸铵、铼粉中痕量钠的方法,对样品的预处理和测定钠的条件进行了研究。结果表明:水溶解法、硝酸溶解法或硝酸-硫酸溶解法溶解样品完全,测得钠的结果吻合;于选定条件下,钠的测定浓度在0.020 0~0.500 0μg/mL范围内线性良好;测定高铼酸、高铼酸铵和铼粉样品中0.27~0.47mg/L、0.000047%~0.00048%和0.000040%~0.00049%的钠含量,检出限、相对标准偏差(RSD,n=7)、加标回收率分别为高铼酸3×10-4μg/mL、6%~10%、98%~102%,高铼酸铵3×10-4μg/mL、8%~9%、96%~102%和铼粉3×10-4μg/mL、5%~9%、96%~103%。方法结果准确、分析快速、操作简便,应用于实际的样品分析,结果满意。     

电感耦合等离子体发射光谱法测定富铼渣中的铼

建立了电感耦合等离子体发射光谱法测定富铼渣中铼含量的方法。对样品的酸密闭消解、碱熔解和测定铼的条件进行了研究。结果表明：于10%盐酸介质、227.525 nm分析线,铼测定浓度在0.20～50.00 μg/ mL线性良好;两种样品分解方法测得铼结果吻合,用于富铼渣样品中1.85%～3.66%铼含量的测定,检出限、相对标准偏差(RSD,n=22)和回收率分别为酸密闭消解法6.46×10-10 μg/mL、0.689%～1.065%和99.95%～100.06%,碱熔解法6.49×10-10 μg/mL、0.691%～1.059%和99.96%～100.31%。     

电感耦合等离子体发射光谱法(ICP-AES)测定富铼渣中的铼

建立了电感耦合等离子体发射光谱法测定富铼渣中铼含量的方法。对样品的酸密闭消解、碱熔解和测定铼的条件进行了研究。结果表明：于盐酸(10%)介质、227.525 nm分析线处,铼测定浓度在0.20～50.00 μg/mL线性良好;两种样品分解方法测得铼结果吻合,用于富铼渣样品中1.85%～3.66%铼含量的测定,检出限、相对标准偏差(RSD,n=22)和加标回收率分别为酸密闭消解法6.46×10-10 μg/mL、0.69%～1.1%和99.95%～100.06%,碱熔解法6.49×10-10 μg/mL、0.69%～1.1%和99.96%～100.31%。     

高含量铼的紫外分光光度法测定研究

采用紫外分光光度法测定了高含量铼样品中的铼.研究了过氧化氢溶解和氢氧化钠碱熔对钨铼、钼铼合金样品的不同前处理过程,确定了铼的最佳测定条件为:在50 mL容量瓶中加入40 mL氢氧化钠(50％),4 mL盐酸羟胺(1％),反应30 min后在波长300 nm处测定.测定了钨铼、钼铼合金以及高铼酸铵中的铼,相对标准偏差(n...     

铼(Ⅶ)催化Na_2TeO_4与SnCl_2氧化还原反应及其应用研究

研究了在硫酸介质中,铼催化碲酸和氯化亚锡的氧化还原反应速率,建立了催化动力学光度法测定痕量铼的方法,优化了高铼酸钾-柠檬酸-碲酸钠-聚乙烯醇-二氯化锡反应的实验条件;测定了催化反应的表观活化能Ea'=15.87 kJ/mul和表观速率常数K'=1.28×10-3s-1,铼含量在0.004～1.2μg/mL范围内服从比尔定律.回归方程Y=0.129 cμg/10mL+0.016 3;相关系数r=0.997;应用于钼灰、钼精砂等矿样中铼的测定,测定结果的RSD≤±5%(n=5),加标回收率为98.0%～100.1%(n=5),符合实用性要求.     

氧化镁烧结-电感耦合等离子质谱法测定冰铜中的铼

本文建立了一种利用电感耦合等离子体质谱法（ICP-MS）测定冰铜中铼的方法。样品经氧化镁烧结,热水浸取法处理,溶液经732强酸型阳离子交换树脂处理交换去除干扰离子,实现了ICP-MS直接测定冰铜中的铼。实验结果表明,在最佳试验条件下,方法的检出限可低至0.010mg/t,加标回收率为92.00%~104.00%,测定结果的相对标准偏差（RSD,n=7）小于5%,测定结果令人满意。由此可见,该方法精密度高,准确度高,可用于冰铜中铼的测定。     

氧化镁烧结-电感耦合等离子体质谱(ICP-MS)法测定冰铜中的铼

建立了一种利用电感耦合等离子体质谱(IC P-M S)法测定冰铜中铼的方法.样品经氧化镁烧结,热水浸取处理,溶液经732强酸型阳离子交换树脂处理交换去除干扰离子,实现了IC P-M S法直接测定冰铜中铼的方法.实验结果表明,在最佳实验条件下,方法的检出限可低至0.010μg/kg,加标回收率为92.0％ ～104％,测...     

电感耦合等离子体原子发射光谱法(ICP-AES)测定富铼渣中的铼

建立了电感耦合等离子体原子发射光谱法测定富铼渣中铼含量的方法。对样品的酸密闭消解、碱熔解和测定铼的条件进行了研究。结果表明:于盐酸(10%)介质、227.525nm分析线处,铼测定浓度在0.20~50.00μg/mL线性良好;两种样品分解方法测得铼结果吻合,用于富铼渣样品中1.85%~3.66%铼含量的测定,检出限、相对标准偏差(RSD,n=22)和加标回收率分别为酸密闭消解法6.46×10-10μg/mL,0.69%~1.1%和99.95%~100.1%,碱熔解法6.49×10-10μg/mL,0.69%~1.1%和99.96%~100.3%。     

电感耦合等离子体质谱测定钼矿石中的铼

以三酸消解钼矿石中的铼, 不经分离富集, 用电感耦合等离子体质谱法直接测定钼矿石样品中的铼。方法检出限可达0.012μg/g , 通过对国家岩石一级标准样品的测试, 测定结果一致;对GBW07285标准样品11 次测定的相对标准偏差(RSD) 为1.13%。     

四酸密闭消解-电感耦合等离子体质谱(ICP-MS)法测定铀矿中的铼和钪

建立一种准确测定铀矿中铼和钪含量的方法,为铀矿中伴生元素的分析与研究提供数据支持、对探勘铼钪矿实现战略资源合理利用化有着重大意义。采用氢氟酸-硝酸-盐酸-高氯酸四酸溶解样品,利用密闭聚四氟乙烯坩埚-电热板加热方式来测定铼钪,建立了电感耦合等离子体质谱(ICP-MS)法测定铀矿中铼和钪的方法,探讨了分解方法、称样量、酸用量、溶样温度及时间、基体干扰、内标选择的影响。实验结果表明：酸溶分解结果准确性高于碱溶分解,3 mL HF、4 mL HNO3、2 mL HCl和1 mL HClO4为最佳消解体系,0.05 g~0.10 g、10 mL~12 mL为最佳称样量和酸用量,闭盖160 ℃、开盖190 ℃ 18 h为最佳溶样条件,选择碰撞气流速为3.0 mL/min,稀释气流速为0.8 L/min降低基体干扰,In作为内标能够达到测试要求。该方法操作简单同时将铼钪测试,其中铼和钪的检出限分别为0.006 mg/kg和0.366 mg/kg;铼准确度在92.9%~98.4%,相对标准偏差在2.4%~5.7%,钪准确度在93.5%~98.2%,相对标准偏差在1.6%~6.2%;铼加标回收率为87.2%~93.8%,钪加标回收率为90.7%~92.3%,检出限低,精密度良好,灵敏度低满足铀矿中铼和钪的分析要求。     

利用离子膜电解法改进过硫酸铵生产研究

国内工厂生产过硫酸铵大多采用工艺简单且产品纯度高的电解法,但是电解法在生产过程中存在能耗过高的问题。这一问题限制了过硫酸铵在许多领域的进一步发展。针对这一现象,对硫酸铵电解生成过硫酸铵的设备及工艺进行设计和研究,以期达到降低能耗的目的。实验基于零极距和离子交换膜电解槽的设计,研究了加酸量、抑制剂用量、出入口温度和电解液浓度等因素对电解效率的影响。结果表明,在电解液中加酸并且在阳极液中添加抑制剂对提高电流效率和降低槽电压具有很大的影响,在最优条件下电流效率可达到98%,生产过程能耗显著降低。另外,电解槽还具有连续性生产、占地面积小的优势,进一步解决了厂家所面临的生产成本过高的问题。     

Electrodecomposition in subcritical water using o-xylene as a model for benzene, toluene, ethylbenzene, and xylene pollutants

The possibility of the combination of electrolysis and subcritical water as a novel electrolyte was investigated. A stainless steel reactor was used as an undivided electrochemical cell containing platinum as the anode and a stainless steel reactor as the cathode. At first, the effect of temperature on the electrolysis current as the main parameter was studied in a cell containing only pure water and a supporting electrolyte. It was realized that the electrolysis current (and, consequently, the electrolysis efficiency) increased linearly with temperature because of the change in viscosity and other physicochemical properties of subcritical water. As a result, at 553 K the electrolysis efficiency was over 14-fold higher than that under ambient conditions. The possibility of the applicability of the above combined techniques for the decomposition of o-xylene was also followed as a model for benzene, toluene, ethylbenzene, and xylene (BTEX) compounds. The effect of experimental conditions such as the electrolysis duration, the electrolysis voltage, and the temperature of subcritical water was investigated. Several decomposed products were identified. o-Xylene was directly electro-oxidized to 2-methylbenzyl alcohol and consecutively to the other oxidation products. Also, hydroxide ions were oxidized to oxygen molecules, where hydrogen was generated on the cathodic surface. The final oxidation product of the electro-oxidation reaction was identified as carbon dioxide. The results indicate that more than 95% of o-xylene can be decomposed under optimum conditions.     

基于离子液体的单滴液相微萃取-高效液相色谱法测定水中杀螨隆农药残留

建立了基于1-辛基-3-甲基咪唑六氟磷酸盐离子液体的单滴液相微萃取-高效液相色谱测定水中的杀螨隆农药残留的新方法.考察了萃取剂种类、萃取剂体积、液滴大小、萃取时间、搅拌速度、温度、盐度等对萃取效率的影响.在最佳条件下,该方法的线性范围为0.05～5 mg/L,r2=0.9994,RSD为2.1%(n=6),检出限为0....     

高铁酸盐电化学合成的研究

采用电化学阳极氧化法制备高铁酸盐,研究制备条件对电解产率的影响.结果表明,灰口铸铁是较为理想的阳极材料.在以14mol·dm-3NaOH作电解液、20℃和电流密度4.54mA·cm-2条件下电解1h,得最高电流效率为68.5%,优于使用KOH作电解液.     

Optimization of solid‐phase microextraction using Taguchi design to quantify trace level polycyclic aromatic hydrocarbons in water

This article introduces a simple, rapid, and reliable solid‐phase microextraction (SPME) method coupled with GC‐MS for the quantitative determination of 16 polycyclic aromatic hydrocarbons in water. In this study, the Taguchi experimental design was used to optimize extraction conditions of polycyclic aromatic hydrocarbons using SPME method to obtain highly enriched analytes. Consequently, quantitative determination of polycyclic aromatic hydrocarbons in water was achieved by GC‐MS technique. The selected parameters affecting enrichment of polycyclic aromatic hydrocarbons were sample extraction time, stirring speed, temperature, ionic strength, and pH. The study revealed that optimal operating conditions were found to be 90‐min extraction time, 1400 rpm stirring speed, and 60°C sample temperature. The effect of ionic strength and pH were shown to be insignificant. Optimized conditions were also reevaluated by placing the 16 polycyclic aromatic hydrocarbons into several subgroups based on their molecular weight. The extraction efficiency of polycyclic aromatic hydrocarbons with low molecular weight was shown to be a function of only the extracting temperature. Satisfactory results were obtained for linearity (0.983–0.999), detection limits (2.67–18.02 ng/L), accuracy (71.2–99.3%), and precision (4.3–13.5%). The optimum conditions reported by other design approaches were evaluated and generalized optimum conditions were suggested.     

On-line electrolytic dissolution of solid metal samples and determination of copper in aluminium alloys by flame atomic absorption spectrometry

A flow-injection system was developed in which alloy metal samples are electrolytically dissolved and the dissolved samples are analysed by flame atomic absorption spectrometry (FAAS). The effects of electrolyte composition and electrolysis parameters on the dissolution of the sample were studied. The method was used for the determination of copper in aluminium alloys. Electrolyte solutions consisting of 0.2–1.0 M nitric acid are better than other electrolytes tested with regard to both alloy sample dissolution and determination of copper by FAAS. The peak height increases linearly with the electrolysis time or current within a certain range. The detection limit depends on the sensitivity of the detector used, and can be improved by increasing the electrolysis time or current. Generally, aluminium alloys containing 0.5–10% copper can give suitable signals for FAAS determination. The reproducibility of electrolysis and determination is about 4% for the same sampling points and 5% for different sampling points on the alloy sample.     

Determination of lead in sea water by electrothermal atomic absorption spectrometry after electrolytic accumulation on a glassy carbon furnace

Lead in sea water is determined by combining in situ preconcentration of the analyte on a proper glassy carbon furnace from flowing solutions, with electrothermal atomic absorption spectrometry. The apparatus is a modified version of a prototype previously tested for lead determination in different salt solutions and for mercury determination in sea water. The effects of experimental parameters such as pH, flow rate, electrolysis current, electrolysis time, etc., are described and the optimum conditions for determination of lead are given. The relative standard deviation at 1.5 ng Pb ml^-1 is ±1%, and the detection limit (twice the standard deviation of the blank) is 0.03 ng ml^-1.     

EDTA滴定法测定含锌物料中氧化锌

采用氯化铵-氨水体系溶解试样,干过滤后,向移取的滤液中加入氯化钡和硫酸共沉淀铅离子,过滤分离硫酸铅沉淀,向滤液中加人抗坏血酸、氟化钾、硫代硫酸钠等掩蔽剂掩蔽少量干扰元素。在pH=5~6的乙酸-乙酸钠缓冲溶液中,以二甲酚橙为指示剂,用EDTA标准滴定溶液滴定测得结果为氧化锌、水溶性锌和镉合量,扣除由原子吸收光谱法测得的水溶性锌量和镉量,即为氧化锌量。对总氨浓度、氯化铵-氨水浓度比、溶液加入量、搅拌时间、共存离子干扰、精密度等进行了实验,建立了EDTA滴定法测定含锌物料中氧化锌物相的分析方法。实验证明,氧化锌含量在24%~83%时,方法精密度(RSD)为0.25%~0.54%,加标回收率在99%~104%,完全满足含锌物料中氧化锌的测定要求。