石脑油中砷含量的测定

采用分光光度法测定石脑油中的砷含量,讨论了有关条件的变化对测定结果的影响,试验证明砷在低浓度范围内有良好的线性关系,能快速、准确测定石油油中的微量砷。     

番茄红素中砷含量测定

以氢化物生成法为砷原子化手段,采用原子吸收分光光度法测定番茄红素中砷含量.本实验选定条件下,砷的检测限为8×10-10,精密度RSD为3.2%,准确度以回收率计为94.5%.结果表明该方法专属性好,灵敏度高,线性范围宽,测定结果准确可靠,适用于番茄红素中砷含量的测定.     

硫铁矿中砷和磷含量的联合测定

本文利用砷和磷可以同时与铋盐、钼酸铵形成各自的杂多酸络合物的特点,用铋钼蓝分光光度法联合测定硫铁矿石中的砷和磷。反应最佳吸收波长为700nm,最佳显色时间为15min,实验表明该方法线性关系良好,精密度与加标回收率均满足质量要求。     

活性炭中痕量砷元素的测定

建立了氢化物发生器和原子吸收分光光度法测定活性炭中痕量砷元素的方法;介绍了该实验方法的测定原理,分析讨论了实验条件对测定结果的影响;并观察比较了炭化料、活性炭和降灰料的砷含量与强度的变化。     

茶叶中砷、铅盐含量的测定

在有些不合格的茶叶中砷和铅的含量较高,茶叶中砷和铅主要来自于土壤和农药的施用.按我国国家标准规定[1-2]:茶叶中砷的含量不得高于0.5mg/kg;铅的含量不得高于1mg/kg.砷的化合物具有强烈的毒性,人若服用0.005g-0.05g就可引起急性中毒,服用0.1 g-0.2g即可致死[3];铅是有害金属之一,当人们长...     

影响砷钼蓝分光光度法测定煤中砷含量因素的探析

砷是煤中有毒有害的微量元素之一,主要通过煤炭的燃烧释放到环境中。在对参考文献分析和不断试验总结的基础上,对实验中影响砷钼蓝分光光度法测定煤中砷含量的因素进行了探析,并提出了一些注意事项和改进方法。     

分光光度法测定磷矿湿法磷酸中砷含量

本文提出了将磷矿和湿法磷酸试样分解后 ,在硫酸介质中 ,以二氯化锡和金属锌还原高价砷为砷化氢气体 ,用二乙基二硫代甲酸银一氯仿溶液吸收 ,砷化氢将银还原而析出稳定的红色胶状元素银 ,以此进行砷的分光光度法测定。     

新银盐光度法测定铁矿石中砷的含量

研究了将新银盐法测定砷的发生部分改用锌粒发生,再用新银盐吸收液吸收,分光光度法测定。该法消除了有机试剂,用锌粒代替硼氢化钾发生,价格便宜,灵敏度大大提高,ε达到2．6×10^4。     

黄磷中砷含量测定方法的改进

对ＧＢ７８１６－８７中光度法测定黄磷中砷含量的方法进行了改进。考察了黄磷样品制取方法,处理条件,如温度、酸度等对分析结果的影响。改进的方法具有样品易处理、分析速度快、节约试剂等优点。     

分光光度法测定水溶液中微量的Sb(Ⅲ)

Sb^3 与Cr^4 在水溶液中可瞬间充分反应，利用Cr^4 与二苯基碳酰二肼的灵敏显色，间接测定水溶液中的Sb(Ⅲ），最低可测到0．01ppm的Sb(Ⅲ），     

有机物中微量砷测定方法的改进

在对有机物中微量砷测定方法综合分析的基础上，选用了砷斑法￣［１］与Ａｇ－ＤＤＴＣ法￣［２］相结合的方法检测有机物中的微量砷。重点对Ａｇ－ＤＤＴＣ法的操作内容作了两处改进。实验表明，新方法检测有机物中的微量砷快速、准确。     

荧光桃红光度分析法测定药物制剂中盐酸氯丙嗪

在酸性介质中,盐酸氯丙嗪与荧光桃红反应,使荧光桃红溶液颜色发生明显改变,据此建立了一种研究测定盐酸氯丙嗪的新方法.最大吸收波长为540 nm,表观摩尔吸光系数为1.49×10(4)L/(mol·cm),盐酸氯丙嗪的浓度在0.5～3.0 μg/mL范围内呈良好的线性关系,检测限为0.34 μg/mL,相对标准偏差为1.2...     

分光光度法对2,4,6—三氯苯肼的测定研究

在酸性条件下,2,4,6-三氯苯肼与碘酸钾反应生成碘,用分光光度法测定碘,从而间接测定2,4,6-三氯苯肼。     

Quality of groundwater in eastern Croatia. The problem of arsenic pollution

Groundwater in the area of eastern Croatia contains high concentrations of iron, manganese, ammonia, organic substances and arsenic. The appearance of inorganic arsenic in groundwater is mainly caused by arsenic from natural geological sources. Since the groundwater is the main source of drinking water for the population in this area, almost 200,000 people are daily drinking water with arsenic concentration ranging from 10 to 610 μg/L. The Croatian legislation recently revised the maximum concentration limit (MCL) for arsenic in drinking water to 10 μg/L. The population in the two towns (Osijek and Vinkovci) of this region is supplied with groundwater processed by coagulation-filtration method, but in the other towns and villages water treatment implies only rapid sand filtration. Both methods for water treatment have resulted with higher arsenic concentration than MCL, so the main goal of this study was determination of population exposure to arsenic via drinking water and possible improvement of drinking water quality. Population exposure to arsenic via drinking water is determined with hair analysis, since the hair arsenic concentration is one of three most commonly employed biomarkers used to identify or quantify overall arsenic exposure. During this study the preliminary analyses of hair arsenic concentrations in several towns and villages in eastern Croatia were provided. The positive correlation between heightened arsenic concentration in drinking water and hair arsenic concentration was determined. In order to improve drinking water quality e.g. arsenic removal from contaminated drinking water, different modified adsorbents were used and compared (zeolite–clinoptilolite, manganese greensand and cationic exchange resin). Adsorbents were chemically modified and saturated with Fe(III) ions, while the arsenic solutions were prepared by processed groundwater.     

Cyclic voltammetry study of arsenic in acidic solutions

An electrochemical investigation of arsenic species in acidic solutions, using cyclic voltammetry at a platinum rotating disk electrode, has been carried out. A well defined peak at about 1 V_SCE, with a large overpotential (>0.5 V) is attributed to the oxidation of As(III) to As(V). The reaction is under the mixed control of ionic transport and charge transfer. The corresponding reduction of As(V) is not observed in the potential range of the study (−0.6 to +1.2 V_SCE). As(V) is not electrochemically active in this range and it has no effect on hydrogen evolution. With As(III) in solution, hydrogen evolution on Pt is shifted towards more negative potentials and it takes place simultaneously with arsine production. A small cathodic peak at −0.2 V_SCE and a corresponding anodic peak at +0.3 V_SCE are attributed to the deposition of a thin layer of As by reduction of As(III) and its dissolution.     

An overview of arsenic removal by pressure-drivenmembrane processes

Management of hazardous wastes, such as arsenic, is one of major public concern. Arsenic is a naturally occurring metalloid, which is widely distributed in nature. Recently, arsenic in drinking water attracted attention because some of the drinking water resources contain considerable concentrations of arsenic which cause acute; and chronic symptoms in many countries, especially in Bangladesh, China, Mongolia, and Taiwan. In 2001, the USEPA promulgated a rule lowering the arsenic MCL from 5 μgL⁻¹ to 10 μgL⁻¹. This paper offers an overview of geochemistry, distribution, sources, regulations, acute and chronic symptoms, and applications of membrane technologies in the water treatment research that have already been realized or that are suggested on the basis of bench or lab scale research. These membrane technologies include RO, NF, UF, and MF. Most of theses applications have proven to be reliable in removing arsenic from water. The possible influence of some source water parameters, membrane material, membrane types, membrane processes on arsenic removal efficiency by membrane technologies are also explored. This review paper also offers data relating to regulations of arsenic standard, acute and chronic symptoms that are caused by the exposure of arsenic to explain why water treatments need to use the membrane technology to meet the MCL standard.     

Porous silicon functionalization for possible arsenic adsorption

Thiol-functionalized porous silicon (PS) monolayer was evaluated for its possible application in As (III) adsorption. Dimercaptosuccinic acid (DMSA) attached to mesoporous silicon via amide bond linkages was used as a chelate for As (III). Two different aminosilanes namely 3-(aminopropyl) triethoxysilane (APTES) and 3-aminopropyl (diethoxy)-methylsilane (APDEMS) were tested as linkers to evaluate the relative response for DMSA attachment. The aminosilane-modified PS samples were attached to DMSA by wet impregnation followed by the adsorption of As (III). Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) have been used to identify the functional groups and to estimate the As (III) content, respectively. FTIR spectroscopy confirmed the covalent bonding of DMSA with amide and R-COOH groups on the nanostructured porous surface. XPS confirms the preferred arsenic adsorption on the surface of PS/DMSA samples as compared to the aminosilane-modified and bare PS substrates.     

测定饲料中砷的研究

测饲料中砷一般采用Ag-DDTC光度法,本文主要对该法的操作进行一些探讨.