对氯偶氮氯膦分光光度法测定血清中的镁

本文利用对氯偶氮氯膦(CPAPCI)与镁的显色反应,测定了血清中镁含量。与 AES、AAS 法比照,本法简便,结果满意。     

非完全消化-火焰原子吸收光谱法测定指甲中的镁锌

建立了非完全消化-火焰原子吸收光谱法快速测定指甲中镁、锌的分析方法,在低温下用浓硝酸消解样品。可获得均匀、透明的样品溶液。以空白溶液为参比,用工作曲线法测定。对样品处理条件、化学干扰、硝酸的影响、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。测定结果的相对标准偏差小于2.9％,测定结果为灰化法一致,相对误差小于±2.0％。方法简便、快速、准确。     

火焰原子吸收法测定人参中的微量镁

通过干法灰化、混酸消化、硝酸溶解的方法处理样品,利用火焰原子吸收法测定人参中微量镁的含量。待测溶液在0.06～7.0μg.mL-1范围内有很好的线性关系,回归方程为A=0.0565C+0.0405,相关系数为0.9987,检出限为0.008μg.mL-1,特征浓度为0.017μg.mL-1/1%,回收率为97.7～103.2%。方法适用于测定各种中药材中的微量镁含量。     

DCB-DNA作为钙镁络合滴定指示剂的研究

本文首次研究了DCB-DNA作为钙镁络合滴定指示剂的条件及应用于水泥、高炉矿渣和白云石等试样中氧化钙、氧化镁含量测定的可能性。研究结果表明:在PH=10.0的氨性缓冲溶液中,加入0.1％的DCB-DNA作指示剂,以0.02mol·1~(-1)的EDTA标准溶液进行滴定,溶液颜色由蓝色变为红色。利用乙酰丙酮作掩蔽剂可测定钙镁混合样中钙含量。此指示剂终点颜色变化敏锐,准确度高,选择性好,是络合滴定钙镁的优良指示剂。     

Accumulation of deicing salts in soils in an urban environment

Examining rates of deicing salt accumulation and leaching in urban soils is important for understanding the distribution and movement of salt in the environment. We examined autumn concentrations of deicing salts in soils in a moderately dense urban landscape in eastern New York State. The study area contrasted to the isolated, rural highways examined in previous studies. While NaCl was the most abundantly applied salt, Mg²⁺ (apparently from MgCl₂, a secondary deicing salt) was the most abundant salt cation in soils. Moderate Na⁺ levels, and equivalent concentrations at depth and in surface samples, indicate that leaching of Na⁺ is rapid in this system. Leaching may ameliorate toxicity for land plants but accelerate inputs to aquatic systems. In contrast to rural highway studies, where salt levels declined rapidly with distance to pavement, Na⁺ remained elevated at the maximum distance measured. Airborne salt dispersal and dense networks of pavement likely contribute to widespread elevated salt levels. This semi-urban setting had salt levels high enough to be toxic to terrestrial plants and soil protozoa. Even moderate levels of development can have dramatic effects on salt inputs into soils and aquatic systems.

西藏环拉萨地区土壤—牧草—家畜系统中Cu等六种元素含量的分析

对西藏环拉萨地区土壤、牧草、家畜 (羊 )被毛中六种元素含量进行了测定。结果表明 :该区土壤、牧草及家畜被毛中Cu、Fe、Zn、Mn、Mg五种元素均不表现缺乏 ,但土壤及牧草中Se含量处于缺乏的临界水平 ,家畜被毛中Se含量低于其缺乏临界值 ,提示该区为低Se生态。     

溶胶-凝胶工艺MgO薄膜制备及表征

采用溶胶-凝胶工艺制备了MgO薄膜.X射线衍射谱显示,随热处理温度升高,薄膜结晶质量提高;原子力显微镜观测也得到相同的结果,且随热处理温度升高,薄膜表面粗糙度增加.