二溴羧基偶氮胂双峰双波长光度法测定绿茶和大米中的稀土总量

在酸性介质中,二溴羧基偶氮胂与稀土元素形成稳定的蓝紫色络合物,试剂和络合物的最大吸收波长分别为534nm和636nm,本文采用双峰双波长吸收光光度法,测得稀土元素含量在0~20μg/25mL范围内符合比耳定律,结果表明比单波长光度法的灵敏度有显著提高,摩尔吸光系数可达1.54×105~1.71×105。该法受酸度及共存离子影响小,能直接用于茶叶和大米中痕量稀土总量的测定,经加标回收试验,回收率在89%~105%,结果满意。该方法具有灵敏、准确、快速、简便的特点。     

二溴羧基偶氮胂分光光度法测定球墨铸铁中稀土总量

在０．３６ｍｏｌ／Ｌ硫酸介质中，铈稀土与二溴羧基偶氮胂形成兰紫色配合物，其最大吸收位于６３２ｎｍ处，表观摩尔吸光系数为１．４０－１．２８×１０＾５。（Ｌａ、Ｃｅ、Ｐｒ、Ｎｄ、Ｓｍ）在草酸存在下，可不经分离直接测定球墨铸铁中０．０１０－０．０５０％稀土总量。     

二溴羧基偶氮胂分光光度法测定废水中铅

研究了二溴羧基偶氮胂(DBKAA)与Pb2+的显色反应,建立了微波消解-分光光度法测定废水中Pb2+的方法。实验结果表明,以硝酸、过氧化氢为消解剂,消解功率为480 W、消解时间为3 min时水样消解效果最佳;在pH 10,室温25℃条件下,溶液中Pb2+与二溴羧基偶氮胂生成蓝紫色络合物,其最大吸收峰在590 nm波长处,表观摩尔吸光系数为3.9×103L.mol-1.cm-1。25 mL溶液中,吸光度值与Pb2+在0.11~15μg范围内呈线性关系,方法检出限为24.8μg/L。本法用于含铅废水中Pb2+的分析,加标回收率为99%~102%,相对标准偏差为1.3%~1.9%,测定结果与原子吸收光谱法测定结果无显著差异。     

新显色剂二溴羧基偶氮胂分光光度法测定钨合金中的钍

本文介绍了用新显色剂二溴羧基偶氮胂分光光度法测定钨合金中的钍.在0.5mol/L硫酸介质中,钍与新试剂形成蓝紫色配合物,在630nm处具有最大吸收,摩尔吸光系数为1.15×10~5L·mol~(-1)·cm~(-1),配合物的组成为Th:R=1:2.钍量在0～50μg/25ml范围内符合比尔定律.许多常见离子在xmg乃至xxmg时不干扰测定.对钨合金中钍的测定获得了满意结果.     

二溴羧基偶氮胂分光光度法测定锆

二溴羧基偶氮胂分光光度法测定锆夏心泉,赵书林,谭洁,李秋,王维忠（沈阳化工学院高分子化工系,沈阳,１１００２１）锆的分光光度法测定以偶氮胂Ⅲ、偶氮氯膦及其衍生物为显色试剂的方法很多［１～３］。本文研究了二溴羧基偶氮胂为显色试剂分光光度测定锆的方法及最...     

二溴羧基偶氮胂光度法测定钕铁硼合金中的钕

提出了二溴羧基偶氮胂作为显色剂的光度法测定钕铁硼中钕的方法。对各种分析条件进行了试验。用铁溶液打底以抵消铁对钕的干扰。本方法简便、快速、准确，适用于日常分析。     

二溴邻硝基偶氮胂分光光度法测定微量钯

研究了3-[(2-胂酸苯基)偶氮]-6-[(4,6-二溴-2-硝基苯)偶氮]-4,5-二羟基-2,7-苯二磺酸(二溴邻硝基偶氮胂)与钯(Ⅱ)的显色反应,建立了一种测定微量钯的新方法。结果表明:在盐酸介质中和CTMAB存在下,钯与二溴邻硝基偶氮胂生成1∶2的紫红色络合物,λmax=566nm,ε566=1.79×105L.mol-1.cm-1。10mL显色液中,钯量在0～18μg范围内符合比尔定律。本法用于钯碳催化剂和含钯分子筛中钯的测定,结果与原子吸收光谱法相吻合,相对标准偏差为1.42%和0.42%,回     

铈-二溴羧基偶氮胂褪色光度法的研究及应用

在H2SO4介质中,Ce(Ⅳ)对二溴羧基偶氮胂具有很强的氧化褪色作用,且褪色程度与Ce(Ⅳ)量线性相关,据此建立了一种测定痕量Ce(Ⅳ)的新方法。结果表明,在0.05mol/LH2SO4溶液中,褪色溶液的最大吸收波长为530nm,表观摩尔吸光系数为7.2×106L.mol-1.cm-1。25mL溶液中,有色溶液的吸光度差值与Ce(Ⅳ)量在0.25～10μg范围内呈线性关系,方法检出限为4.5μg/L。该法不需预处理,可直接用于球墨铸铁及合金中痕量铈的测定,测定值与认定值相符合,RSD为1.0%～3.6%。     

双波长双指示物催化动力学光度法测定痕量银的研究

研究了在pH 3.5的HAc—NaAc缓冲溶液介质中,以乳化剂OP为增溶剂,邻菲罗啉和α,α’,-联吡啶活化银离子催化过硫酸钾氧化亚甲基蓝和甲基紫褪色的指示反应,通过测量660 nm和590 nm下催化体系和非催化体系吸光度的变化,建立了双波长双指示物催化动力学光度法测定痕量银的新方法。在最佳实验条件下,测定银的线性范围为0.002～0.080μg/mL,检出限为6.5×10~(-10)g/mL。用于定影废液中痕量银的测定,相对标准偏差为1.5%,加标回收率为98.3%。     

双波长K系数分光光度法同时测定原油中铝、铁

显色体系为Al3+(Fe3+)-邻硝基苯基荧光酮-CTMAB-OP,以硫脲掩蔽干扰离子Cu2+,氟化钠掩蔽Al3+,在610 nm波长下测定铁,再用K系数法在556 nm波长下测定铝,建立了双波长K系数-分光光度法同时测定原油中铝、铁的分析方法。对测定条件、共存元素干扰情况进行了考察。人工合成样品回收率:铁为98.3%~99.1%,铝为95.3%~98.2%;样品加标回收率:铁为95.4%~104.5%,铝为95.5%~100.5%。     

石蜡相分光光度法测定稀土的研究

系统研究了稀土 -8 羟基喹啉显色体系在石蜡相中的显色反应。在NH4Cl-NH3·H2 O(pH 9)介质中 ,稀土 -8 羟基喹啉显色络合物可定量被石蜡萃取 ,且固相色阶明显 ,RE2 O3 在 0～ 80 μg/ 5 0mL范围内符合比尔定律 ,从而建立了测量稀土的新的固相分光光度法。大多数干扰离子可通过控制溶液酸度进行萃取分离。方法应用于江西稀土矿中稀土总量的测定 ,结果满意。     

4-硝基-4′-氟苯基重氮氨基偶氮苯双波长分光光度法测定镍

报道了新含氟显色剂4-硝基-4′-氟苯基重氮氨基偶氮苯与镍(Ⅱ)的显色反应。试验表明,在pH 8.6 Na2B4O7-HCl缓冲溶液、Tween-85存在下,试剂与镍(Ⅱ)形成4∶1的稳定紫红色络合物。最大吸收正峰为504 nm,负峰为424 nm;且在25 mL显色液中镍(Ⅱ)的量在0~4μg范围内符合比尔定律。在两最大正负吸收波长处分别进行单波长分光光度法测定,表观摩尔吸光系数分别为1.13×105,1.06×105L.mol-1.cm-1。再以424 nm为参比波长、504 nm为测量波长进行吸光度叠加的双波长光度法测定,表观摩尔吸光系数为2.17×105L.mol-1.cm-1。加入混合掩蔽剂NaF-硫脲,可消除常见共存离子的干扰。本法可用于测定多元素混合标准溶液和不锈钢中的镍(Ⅱ),回收率为96%~98%,混合标准溶液的测定值与认定值相一致。     

Study on separation of rare earth elements in complex system

The effect of the feed acidity,acetic acid concentration and rare earth concentration on the distribution ratio,separation coefficient and extraction capacity of light rare earth elements were studied in the P204(DEHPA)-HCl system and P507(HEH/EHP)-HCl system both containing acetic acid,respectively. The results showed that the distribution ratio and separation coefficient decreased with increasing of acidity,and increased with increasing of acetic acid concentration and rare earths concentration,and the extraction capacity increased with increasing of acetic acid concentration. When pH value of feed was 2.0,[RE]/[acetic acid] was 1:1 and rare earth concentration 0.35 mol/L,in P204(DEHPA) -HCl system with acetic acid,the maximum separation coefficient(β) reached to βCe /La=4.09,βPr/Ce=1.96 and βNd/Pr=1.53,and the separation ability of this extraction system was better than P507(DEHPA)-HCl system.     

双波长分光光度法测定铜的研究

研究了 2-( 5-硝基-2- 吡啶偶氮 )-5 -二甲氨基苯胺 ( 5 NO2 PADMA)与铜的显色反应 ,建立了双波长分光光度法测定铜的新方法。结果表明 ,在pH 4.5HAc -NaAc缓冲溶液和乙醇存在下 ,Cu与 5 NO2 PADMA生成 1∶2的紫红色络合物 ,最大吸收正峰为 5 5 0nm ,负峰为 45 0nm ,正负峰吸光度绝对值之和与Cu浓度线性相关 ,Cu含量在 0～ 1.0mg/L内符合比尔定律 ,ε550 ,4 50 =6.74× 10 4 ,ε550 =3 .2 4     

Study on non-saponification extraction process for rare earth separation

The purpose of this study was to overcome the disadvantages of ammonia-nitrogen wastewater pollution and high cost of sodium saponification in rare earth separation process. The study focused on the non-saponification extraction technology with magnesia. The influences of the content and particle size of magnesia, reaction time, reaction temperature, and O/A on cerium extraction rate were also discussed. The results showed that the hydrogen ions of extractant were exchanged by rare earth ions when organic extractant and rare earth solution were mixed with magnesia powder, and then the exchanged hydrogen dissolved magnesia to make the acidity of the system stable. The magnesium ions were not participated in the extraction reaction. Non-saponification extraction process of rare earth had been realized. The cerium extraction rate could reach up to 99% in single stage within the optimal reaction conditions.     

Effects of the accumulation of the rare earth elements on soil macrofauna community

The accumulation of rare earth elements(REEs)in soil has occurred due to the pollution caused by the exploitation of rare earth resources and the wide rare earth fertilizers in agriculture.The accumulation of REEs has a toxic effect on the soil macrofauna community.12study samples were collected near a mine tailings dam with a large amount of REEs by distance gradient sample method.The total concentration of REEs was analyzed and the results were compared with that of the sample from a control site.The effects of the amount of REEs in the soil on the soil macrofauna community were also analyzed.The results showed that the accumulation of REEs in soil was significant in the study area and its concentration was strongly correlated with the distance from the pollution source.One-way ANOVA analysis indicated the significant differences in soil macrofauna communities among the different sites.The ordination obtained through the redundancy analysis demonstrated that the concentration of REEs and the total nitrogen,total potassium and pH,had affected the soil macrofauna community.A small amount of REEs in the soil can promote the diversity of soil macrofauna,but a large amount of REEs can reduce its diversity.The insect groups of Carabidae and Dermaptera were comparatively sensitive to the concentration of REEs in soil,and could be used as an indicator of soil pollution of REEs.However,the Formicidae and Stibaropus formosanus exhibited a high tolerance to REEs in soil.We believe that it is very important for the soil environment protection to strictly control the application of the rare earth fertilizers in agriculture in China.