火焰原子光谱法测定中成药丸中钙镁锌

用悬浮液技术处理中成药丸样品，将样品烘干、粉碎、过筛、悬浮于琼脂溶液中制成悬浮液。以Sr^2 溶液作为钙、镁的释放剂，以吸收法测定镁、锌，以发射法测定钙。对样品悬浮液的稳定时间、干扰、试液与空白溶液粘度的一致性及线性范围进行了考察。测定结果的相对标准偏差小于1．7％，加标回收率为96．6％～102．6％。     

非完全消化—悬浮液进样—火焰原子光谱法测定蘑菇中钾、镁、锌

将非完全消化法与悬浮液进样技术相合处理蘑菇样品，即先用浓HNO3低温消解样品至溶液呈透明，再用琼脂溶液悬浮极少量不溶物，制成样品溶液。分别以Sr^2 溶液和NaCl溶液作为测定镁、钾的释放剂和消电离剂。以原子吸收光谱法测定镁、锌，以原子发射光谱法测定钾。对样品处理方法、干扰、线性范围及检出限进行了考察。建立了快速测定蘑菇中钾、镁、锌的火焰原子光谱法。相对标准偏差小于2.8%，加标回收率为97.9%-101.6%。     

悬浮液进样-火焰原子吸收光谱法测定虾仁中的钙、镁

建立了快速测定虾仁中钙、镁含量的悬浮液进样－火焰原子吸收光谱法。将虾仁样品烘干、粉碎、过98μm筛后，制成琼脂悬浮液。以La^3 溶液作为释放剂，用工作曲线法测定虾仁样品中钙、镁的含量。钙、镁的线性范围分别为0-200μg/(25mL)、0－30μg/(25mL)，检出限分别为0.056mg/L、0.0046mg/L。测定结果的相对标准偏差不大于2.4%，测定结果与在灰化法一致，测定钙、镁的平均相对误差分别为-1.3%、-4.2%。     

非完全消化-悬浮液进样-火焰原子光谱法测定蘑菇中的钾、镁、锌

将非完全消化法与悬浮液进样技术相组合处理蘑菇样品 ,即先用浓HNO3低温消解样品至溶液呈透明 ,再用琼脂溶液悬浮极少量不溶物 ,制成样品溶液。分别以Sr2 +溶液和NaCl溶液作为测定镁、钾的释放剂和消电离剂。以原子吸收光谱法测定镁、锌 ,以原子发射光谱法测定钾。对样品处理方法、干扰、线性范围及检出限进行了考察。建立了快速测定蘑菇中钾、镁、锌的火焰原子光谱法。相对标准偏差小于 2 8% ,加标回收率为 97 9%～ 1 0 1 6%。     

悬浮液技术-火焰原子吸收光谱法测定明胶中钙镁

用悬浮液技术处理明胶样品。将样品烘干、粉碎、过筛,制备成琼脂悬浮液。取适量样品悬浮液加入释放剂Sr2+配制成试剂,喷入空气-乙炔火焰进行测定,建立了悬浮液技术-火焰原子吸收光谱法快速测定明胶中钙、镁的分析方法。以空白溶液为参比,用工作曲线法测定。对琼脂溶液用量、化学干扰、试液与空白溶液粘度一致性、背景吸收干扰及检出限进行了考察。测定结果与灰化法一致,相对误差小于±0．9％,相对标准偏差小于5．2％。方法简便、准确。     

悬浮液进样火焰原子吸收光谱法测定豆米类粮食中镁

将样品磨细配制成悬浮液,并对悬浮剂的选择及化学干扰的消除进行了考查。为消除化学干扰，取适量悬浮液，加入La3+溶液制成试液。将试液喷入空气-乙炔火焰，以空白溶液为参比，用工作曲线法进行测定。测定结果与灰化法一致，相对误差小于±1.3％。方法简便、快速、准确。     

悬浮进样原子吸收法测定茶叶中的微量元素

用悬浮液技术处理茶叶样品,即将样品烘干、粉碎、过筛,并悬浮在1.5g/L琼脂溶液中制成均匀的悬浮液,建立了火焰原子吸收快速测定茶叶中微量元素的方法。该法快捷、简便、具有良好的精密度和准确度,应用于实际样品的测定结果满意。     

悬浮液进样-火焰原子吸收光谱法测定烟叶中铜铁

用悬浮液技术处理烟叶样品,即先将样品烘干、粉碎、过筛,然后悬浮在 1.5 g·L-1琼脂溶液中制成均匀的悬浮液,以盐酸作为铜、铁的解释剂及用工作曲线法测定。建立了快速测定烟叶中铁、铜的FAAS法。测定结果的相对标准偏差<4.8%,加标回收率为 98.1%~102.1%。方法简便、快速、准确。     

悬浮液进样-火焰原子吸收光谱法测定中草药中的微量铜

将悬浮液进样技术应用于火焰原子吸收光谱法,建立了快速测定中草药中微量铜的新方法。将样品磨细,制成悬浮液,喷入空气－乙炔火焰,以空白溶液为参比,用氘灯进行背景和扣除,以标准加入法测定。测定结果与灰化法一致,两种方法的相对误差小于±３．６％,ＲＳＤ小于２．５％,检出限为０．０５７ｍｇ／Ｌ。     

悬浮液进样-火焰原子光谱法测定烟叶中的钾锰

用悬浮液技术处理烟叶样品 ,即将样品烘干、粉碎、过筛 ,并悬浮在 1 .5g L琼脂溶液中制成均匀的悬浮液。以钙作为锰的释放剂和以钡作为钾的消电离剂。用工作曲线法测定 ,以火焰原子发射法 (FAES)测定钾 ,以火焰原子吸收法 (FAAS)测定锰。建立了快速测定烟叶中钾、锰的FAS法。对化学干扰、介质的影响及检出限进行了考察。测定结果的相对标准偏差 <2 .4% ,测定结果与灰化法一致 ,相对误差 <± 2 .5 %。     

Determination of trace amounts of rare earth elements by neutron activation analysis after preconcentration using hydrated magnesium oxide

A preconcentration method of 13 rare earth elements (REES) was studied for neutron activation ananlysis (NAA). Hydrated magnesium oxide was used as the preconcentration agent to absorb the REES ions from aqueous solution onto the solid magnesium oxide, which was separated and analyzed. It was observed that the Langmuir equation for isothermal adsorption was well obeyed by the REES under the condition studied. The efficiency of the preconcentration process using hydrated magnesium oxide was critically examined for each of REE and for mixture of REES by preparing a known volume of solution containing known amount of trace REES. NAA was used to analyze REES recovered by the preconcentration process. It was found that the REES recoveries were satisfactory and the preconcentration process is reliable. There are several resort resort areas in Taiwan where local people are enjoying its hot spring water. It is generally believed that the hot spring water spa would bring about some sorts of therapeutic functions. The preconcentration method developed above, was applied to analyze the trace amounts of REES in hot spring wate in Taiwan.     

镁铝复合氧化物载体的制备与性质研究

以硝酸镁和硝酸铝为原料，用氨水溶液作为pH调节剂，采用共沉淀法制备了镁铝复合氧化物载体，研究了制备过程中镁铝比、pH调节剂种类、水解过程pH值的大小、反应温度、焙烧温度及回流晶化温度对复合氧化物载体理化性质的影响。并以RFCC汽油加氢脱硫为探针反应，考察了以镁铝复合氧化物为载体的催化剂选择性加氢脱硫性能。实验结果表明，在镁铝分子比为10、反应温度为80℃、pH值为9.5条件下制备的镁铝复合氧化物载体具有适宜的比表面积和均匀的孔分布，且晶型较完整，结晶度高。以该复合氧化物为载体制备的催化剂具有良好的RFCC汽油选择性加氢脱硫反应性能。     

Fluorimetric sequential injection determination of magnesium using 8-hydroxiquinoline-5-sulfonic acid in a micellar medium

A fluorimetric sequential injection method for the determination of magnesium is proposed. The system is based on the complex formation between Mg(II) and 8-hydroxyquinoline-5-sulfonic acid (HQS). The reaction was carried out in the presence of ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) as a masking agent. Cetyltrimethylammonium chloride (HTAC) was employed as a fluorescence enhancer. The influence of several variables, such as reagent concentration, volumes and pH has been investigated. The reagent was prepared in a 0.1 M Tris-HCl buffer solution (pH 9). A detection limit of 12 mug l(-1) magnesium was obtained. The proposed method was applied to the determination of magnesium in natural waters.     

氢氧化镁纳米片的合成及其润滑性能的研究

以硫酸镁和氢氧化钠为原料,油酸为表面修饰剂,采用原位合成的方法制备出了疏水性的Mg(OH2)纳米片.研究了反应温度、反应物浓度等因素对氢氧化镁纳米片平均粒径的影响.用X-射线粉末衍射(XRD)、红外(IR)和热重(DTA-TGA)及扫描电子显微镜(SEM),对制备出的Mg(OH)2纳米片的结构和形貌进行了表征,证实制备出的Mg(OH)2纳米片具有良好分散性,纳米片尺度为200～300nm,厚度10nm.摩擦实验证明Mg(OH2)纳米片可以作为润滑油中的添加剂来应用.     

Semiautomatic indirect titration of alkaline-earth ions with catalytic endpoint indication

A semiautomatic spectrophotometric method of endpoint indication for indirect catalytic titrations of microamounts of alkaline-earth ions is described. The manganese(II)-catalyzed autoxidation of 1,4-dihydroxyphthalimide dithiosemicarbazone is used as indicator reaction. Calcium and magnesium (10–150 μg), strontium (20–250 μg), and barium (20–450 μg) can be determined by adding a known excess of EDTA to the sample solution and back-titrating the unconsumed inhibitor agent with standard manganese(II) solution. This catalytic method was applied to determine the total concentration in calcium and magnesium (total hardness) in natural waters and milk. The method is fast, accurate (1–3%), precise (0.2–0.8%, relative standard deviation), and specially useful for the determination of microamounts where metallochromic indicator are ineffective (for concentrations ranges below 10^?4M).     

铍试剂Ⅱ—CPB三元络合物分光光度法测定镁

建立了一种以铍试剂Ⅱ为显色剂，在氨性介质中加入表面活性剂，并加入动物胶作为稳定剂，与镁形成三元络合物，用分光光度法测定镁的方法。对测定波长、显色时间及各种组分的用量进行了考察，选择了最佳的实验条件，并进行了回收率实验。     

Purification of magnesium chloride solution used for carnallite synthesis

The neutralization of magnesium chloride solutions and their treatment to remove iron compounds was studied. The possibility of neutralization of free hydrochloric acid with brucite was determined. The effect exerted by the method of stirring of the solution in the course of neutralization was analyzed, and variations of neutralization rate with the solution temperature and with the amount and size of particles of the neutralizing agent were studied.     

Simple test kit based on colorimetry for quantification of magnesium content in natural rubber latex by miniaturized complexometric titration without using masking agent

A simple, low-cost and portable field test kit based on colorimetry with detection by naked eye was developed for determination of magnesium content in natural rubber latex (NRL). The miniaturized complexometric titration between Mg²⁺ and EDTA without any masking agent was a key reaction in this development, which was designed according to the concept of green chemistry by reduction of waste generation and chemical and time consumption. The system enabled quantification of magnesium content in NRL at low concentration with the detection limit being <50 mg L⁻¹, small sample volume uptake (0.18 g, sampling by a small spoon) and use of <1.5 mL reagent volume which was >70 times less than that applied in the conventional method. Moreover, with the presence of potential interference ions, greater selectivity towards magnesium was observed. Furthermore, the reagents used in our developed test kit were stable for >6 months at room temperature. The results obtained on real samples were in agreement with those obtained from the conventional complexometric titration (ISO 17403: 2014(E)) method. The proposed technique provides a low-cost, rapid, simple, selective and on-site analysis of magnesium content in NRL.     

Contributions to the basic problems of complexometry-XX Determination of calcium and magnesium

A new method for the determination of magnesium in the presence of calcium is described. Calcium is masked with EGTA whilst magnesium is titrated with DCTA with Methylthymol Blue as the indicator. Calcium can be determined in the same solution by back-titration of the excess EGTA with calcium chloride solution. The usual masking agents for iron, aluminium and other heavy metals can be used.     

Hydration of medium reactive industrial magnesium oxide with magnesium acetate

Medium reactive magnesium oxide reacts incompletely with available water to form magnesium hydroxide. To enhance the hydration of medium reactive magnesium oxide, the effect of magnesium acetate as hydrating agent was studied. The extent to which different parameters (concentration of magnesium acetate, solution temperature and solid to liquid ratio of MgO to magnesium acetate) influence the hydration rate of a medium reactive industrial sample of magnesium oxide were evaluated. The degree of rehydration measured as percentage Mg(OH)₂being formed, increases from approximately 56% using 0.5 M magnesium acetate solutions at 25°C to 64% at 50°C, to more than 70% at 70°C. The major part of rehydration of the medium reactive MgO sample occurs within the first few minutes of the reaction for all three temperatures studied. This revised version was published online in July 2006 with corrections to the Cover Date.