有机—无机复混肥料中氯离子含量测定中脱色处理的研究

有机—无机复混肥料中有许多样品经处理后的滤液存在很深的颜色(近黑色)，用少量活性碳无法脱色，在测定氯离子含量时终点的判断会产生很大误差。本文参考了HG／T3589—1999中氯含量测定中的前处理方法进行了大量的实验，寻找适合有机—无机复混肥料的脱色最佳条件，使有机—无机复混肥料的脱色难题得到解决。     

附录D(规范性附录) 腐植酸肥料中氯含量的测定方法

正D.1方法原理本方法为GB 18877-2009有机-无机复混肥料和GB 15063-2009复混肥料(复合肥料)中氯离子测定方法的补充,适宜于有颜色的腐植酸肥料中微量氯离子含量的测定。以氯离子选择性电极为指示电极,双液接甘汞电极为参比电极,插入试液中组成工作电池。当氯离子浓度在     

两种测定肥料中氯离子方法的比较

用全自动电位滴定法与佛尔哈德法对复混肥料、掺混肥料、有机-无机复混肥料、水溶肥料、氯化钾等样品中氯离子含量进行测定比较。比较结果显示,全自动电位滴定法测定氯离子比佛尔哈德法所需要配制的化学试剂数量和种类少,且不受溶液颜色干扰,检测范围广,比佛尔哈德法更加快速、准确、简便。在大批量样品测试中,全自动电位滴定法更具有方便、快捷的优势。     

测定有机复混肥中氮,磷,钾含量时的样品处理

生产有机复混肥时,在无机复混肥的原料中加较大量的有机物质,如动物的粪便、骨粉、鱼粉、糖厂滤泥等,这对于改良土壤、增加肥效有较大益处。但我们发现在检测某些含有较大量的有机质的复混肥时,依照ZBG21002专业标准测定氮、磷、钾含量时,会影响测定结果。为此我们对此类复混肥样品进行处理,处理后的试液可供其测定氮、五氧化二磷和氧化钾的含量。     

有机-无机复混肥结晶粉化的机制分析及解决措施

为提高有机-无机复混肥的产品质量,通过实验从水含量和密度两方面分析有机-无机复混肥产品普遍存在的结晶粉化机制。结果表明,水含量高和密度小导致的溶解和重结晶加剧是有机-无机复混肥结晶粉化的主要原因。介绍降低水含量和提高密度的措施,为有机-无机复混肥同行提供生产经验。     

有机-无机复混肥中有机质含量测定方法的探讨

对有机-无机复混肥中有机质含量进行测定分析,对称样量、滴定终点判断、滴定酸度等的影响进行讨论.通过提高称样量以减小测量误差,采用定容后分取体积测定的方法,更易于终点的判断,从而达到更好的测定结果,提高测定的准确度.     

二苯卡巴肼分光光度法对有机-无机复混肥料中铬含量测定的研究

铬是有机－无机复混肥料中的有害元素之一,我国尚未制定有机－无机复混肥料中铬含量测定的标准。本文探索了采用二苯卡巴肼分光光度法测定铬含量的条件,并通过精密度、回 和不同的比较试验,表明该方法对有机－无机复混肥料中铬含量的测定是可行的,也是可靠的,为以后制定相应的国家标准打下基础。     

对两种消化法测定 有机－无机复混肥料中总钾含量的研究

用硫酸－过氧化氢和硝酸－高氯酸分别对有机－无机复混肥料进行消化处理,然后进行总钾含量的测定。实验发现这2种不同的消化方法对钾的测定结果无显著性差异。这2种方法已被列入国家标准“有机－无机复混肥料中总钾含量的测定”。     

对两种消化法测定有机——无机复混肥料中总钾含量的研究

用硫酸－过氧化氢和硝酸－高氯酸分别对有机－无机复混肥料进行消化处理,然后进行总钾含量的测定。实验发现这２种不同的消化方法对钾的测定结果无显著性差异。这２种方法已被列入国家标准“有机－无机复混肥料中总钾含量的测定”。     

微波消解——原子荧光光谱法同时测定有机-无机复混肥料中砷和汞的含量

采用微波消解样品预处理技术和原子荧光光谱法同时测定有机-无机复混肥料中的砷和汞,确定微波消解样品的条件,优化仪器的最佳工作参数。砷和汞的含量分别在0~20μg/L和0~10μg/L范围内有良好线性关系,砷和汞的回收率分别在99.1%~102.0%和98.1%~101.5%,砷和汞的检出限(3σ)分别为0.20μg/L和0.070μg/L。实验表明,该方法具有操作简单、快速、灵敏度高等优点,可适用于有机-无机复混肥料中砷和汞的同时测定。     

佛山市顺德新城区降水中污染物的监测和分析

为掌握佛山市顺德新城区降水中污染物的情况,2015年7月至8月,文章作者分别在雨天进行了降水取样,对降水中的pH、电导率、常见阴离子(F-、Cl~-、NO_3~(2-)、SO_4~(2-))及部分重金属(铅和镉)进行监测分析。选择有相关数据的珠江三角洲和石家庄、厦门等地的降水中污染物的情况进行对比。结果表明,顺德新城区降水中的p H和部分阴离子浓度优于珠江三角洲平均值,酸雨类型属于硫酸和硝酸混合型;其水体洁净程度略差于石家庄;铅和镉的浓度也高于厦门,甚至部分超出了人体能直接接触的安全范围。     

Metabolism of trideuterated iso-lignoceric acid in rats in Vivo and in human fibroblasts in culture

Saturated very long chain fatty acids (fatty acids with greater than 22 carbon atoms; VLCFA) accumulate in peroxisomal disorders, but there is little information on their turnover in patients. To determine the suitability of using stable isotope-labeled VLCFA in patients with these disorders, the metabolism of 22-methyl[23,23,23-²H₃]tricosanoic (iso-lignoceric) acid was studied in rats in vivo and in human skin fibroblasts in culture. The deuterated iso-VLCFA was degraded to the corresponding 16- and 18-carbon iso-fatty acids by rats in vivo and by normal human skin fibroblasts in culture, but there was little or no degradation in peroxisome-deficient (Zellweger’s syndrome) fibroblasts, indicating that its oxidation was peroxisomal. Neither the 14-, 20-, and 22-carbon iso-fatty acids nor the corresponding odd-chain metabolites could be detected. In the rat, the organ containing most of the iso-lignoceric acid, and its breakdown products, was the liver, whereas negligible amounts were detected in the brain, suggesting that little of the fatty acid crossed the blood-brain barrier. Our data indicate that VLCFA labeled with deuterium at the ω-position of the carbon chain are suitable derivatives for the in vivo investigation of patients with defects in peroxisomal β-oxidation because they are metabolized by the same pathways as the corresponding n-VLCFA. Moreover, as iso-VLCFA and their β-oxidation products are readily separated from the corresponding n-fatty acids by normal chromatographic procedures, the turnover of VLCFA can be more precisely measured. A preliminary report of part of this work (Reference 18) was presented at the 5th International Symposium on the Synthesis and Applications of Isotopes and Isotopically Labelled Compounds, Strasbourg, France, June 20–24, 1994.     

高效液相色谱法分析化妆品中微量成分的研究进展

综述了高效液相色谱法在化妆品中防腐剂、防晒剂中紫外线吸收剂以及性激素的检测等几个方面的应用;同时,介绍了分析所用的色谱柱、流动相、使用的检测手段以及样品的提取方法;最后针对目前存在的问题,提出了高效液相色谱用于化妆品中微量成分分析的研究方向和发展前景。     

Denitrification in shallow groundwater in a coastal agricultural area in Japan

In a coastal agricultural area in the central part of Japan (Shizuoka), we found decreasing nitrate concentration with depth in a shallow groundwater, where the depth to water table varied between 0.6 and 1.2 m below ground surface. High nitrate concentrations (5–29 mg N L^–1) were often observed in the upper layer (0–2 m) of the groundwater, but the concentration decreased to less than 1 mg N L^–1 in the deeper layer. Ammonium was scarcely detected, and the concentration of dissolved oxygen was usually low (< 1 mgO₂ L^–1) in the groundwater. Nitrate in the groundwater often had very heavy nitrogen stable isotope ratios (>20{}). There was a negative relationship between nitrogen stable isotope ratio of nitrate and its concentration. When nitrate was injected into the groundwater with acetylene and bromide (a conservative tracer), nitrate concentration decreased to 20% of the initial level within 5 days, accompanied by the increase in nitrite and nitrous oxide concentration and a little change in bromide concentration. These results indicate that microbial denitrification plays a potential role in the decrease of nitrate in shallow groundwater at the study site.     

我国硝酸工业生产技术新进展

系统叙述了我国硝酸工业2000-2007年生产现状及主要技术成果,尤其指出了国产"四合一"机组的成功投运,使我国硝酸国产化装置取得较大的进步,表现在吨酸的铂耗、氨耗和能耗等方面接近国外引进装置水平,同时介绍了国外双加压法硝酸生产技术的进展.我国已成为硝酸生产大国,仍需以先进的技术改造和发展我国硝酸工业,确保我国硝酸工业健康有序地发展,加快从硝酸生产大国向强国迈进的步伐.