电感耦合等离子发射光谱法测定降水中钾、钠、钙、镁

目前测定降水中钾、钠、钙、镁的常用方法主要有火焰原子吸收法、火焰原子发射法和离子色谱法[1]。用火焰原子吸收法测定钾、钠易产生较大的电离干扰,需加入消电离剂,测定钙、镁需加入释放剂,两法操作都较繁琐。对于钾钠浓度大于0.5mg/L的样品在不稀释的情况下必须降低仪器的灵     

盐酸超声-氟离子选择电极法测定复合肥中氟含量

为快捷有效地测定复合肥中氟的含量,采用盐酸浸取过夜、盐酸超声、碱熔、纯水煮沸四种方法提取复合肥中的氟离子,用氟离子选择电极进行测定,全程加标回收;结果发现盐酸超声提取法测得值与碱熔提取法测定值非常接近,并且加标回收率为98.4%~104.2%,相对标准偏差为1.9%;则用盐酸超声提取法测定复合肥中的氟含量方法可靠,方便快速,能够满足复合肥中氟含量的测试要求。     

聚氧化乙烯絮凝-电感耦合等离子体发射光谱法测定土壤中水溶性钾、钠、钙、镁、硫酸根

建立了聚氧化乙烯絮凝-4000r/min离心,电感耦合等离子体发射光谱法（ICP-AES）测定土壤水溶性钠钾钙镁硫酸根离子的方法。本法在常规方法浸提的基础上,加入聚氧化乙烯絮凝剂使溶液中的胶体形成絮凝物聚沉,制得澄清溶液,消除了胶体对钾、钠、钙、镁吸附的干扰;采用电感耦合等离子体发射光谱法一次性测定钾、钠、钙、镁、硫酸根,相较传统方法简便快速,结果准确可靠。本法各离子检出限为0.37-2.91g/g,相对标准偏差小于5.55%,完全满足检测要求。该法操作简便,快速,实用性强,对环境无二次污染,已成功应用于土壤水溶性钾、钠、钙、镁、硫酸根离子的测试分析中,适合土壤批量样品分析。     

化肥成分分析系列标准物质研制

研制了尿素、磷酸氢二铵、氯化钾、高氮磷低氯复合肥、高氮低氯复合肥、高钾硫基复合肥、高钾中氯复合肥、高磷低氯复合肥和平衡型硫基复合肥系列化肥标准物质,样品严格按照相关标准要求进行采集、加工制备、均匀性检验、稳定性检验,由15家不同行业的权威实验室进行协作定值,并对不确定度进行评定.结果表明,样品粒度分布满足样品加工要求,...     

氮、磷、钾复合肥料的试制

为了生产成本低、原料来源广、营养全面的氮、磷、钾复合肥料,在原用磷酸和氢氧化钾中和法生产磷酸二氯钾的基础上,进一步搞科学试验,摸索出了改用氯化钾,磷酸和氨水的生产工艺,所得复合肥料有效养分达80％,含P_5O_5>50％,K_2O>20％,N 5—7％。一、基本原理在减压蒸馏的条件下,氯化钾与正磷酸反应生成糖浆状的复盐[KH_2PO_4·H_3PO_4],然后再用稀氨水中和复盐中的磷酸,即可得到磷酸二氢钾与磷酸二氢铵为主要成分的氮、磷、钾复合肥料。     

近红外漫反射法快速检测复合肥中总氮含量

本文采用数字光栅近红外漫反射技术对复合肥中总氮(N)含量进行测定,以采用标准正态变量转换、趋势变换、导数变换等方法对180个正常复合肥的近红外测量数据进行前处理,然后采用偏最小二乘回归校正方法(MPLS)建立模型,取得对未知复合肥中总氮含量较好的预报结果。该方法优势:(1)检测省时,往往只需几分钟即可完成分析,而且无需称样和消耗化学试剂。(2)其测定标准偏差与凯氏法相比不存在显著性差异。该新方法可对复合肥中总氮含量实现快速简便的连续检测,尤其适合大批量样品。     

火焰原子吸收法间接测定钢中硼和磷

提出了溶剂萃取-火焰原子吸收光谱法间接测定钢中硼和磷的分析方法.在弱酸性介质中硼酸、苯羟乙酸、铁(Ⅱ)以及邻二氮菲能形成稳定的多元离子缔合物,被1,2-二氯乙烷萃取后再用去离子水反萃取,然后测定水相化合物中的铁;在盐酸介质中,磷酸根与钼酸铵形成磷钼杂多酸,被甲基异丁基甲酮萃取后,测定有机相磷钼杂多酸中的钼.并可分别间接测定硼和磷.在优化的反应条件下,硼和磷的质量浓度分别在0.12～3.24及0.04～1.00mg/L范周内时,吸光度与质量浓度之间具有良好的线性关系,硼和磷的检出限分别为0.036和0.015mg/L.以8份样品空白进行测定,得硼和磷的标准偏差分别为1.2%和0.5%.方法用于钢样中微量硼和磷的测定,拓展了原子吸收分光光度计的应用范围.     

重量法测定黄腐植酸含量

腐植酸类物质是一种天然的羟基羧酸,是由死亡植物分解而形成的一种暗黑色无定形物质,由碳、氢、氧、氮和少量硫、磷组成。腐植酸类物质由黄腐植酸(分子量300～400)、棕腐植酸(分子量2×103～2×104)和黑腐植酸(分子量1×104～1×106)组成。生产腐植酸的原料主要有泥煤、褐煤、木煤(柴煤)和风化煤等。腐植酸是一种内表面积很大的高分子有机物,吸湿性强(风干的腐植酸含水可达25%),具有吸附多种微量元素的能力。它同时具有酸性,可使碳酸盐、磷酸盐等分解。黄腐植酸在农业、制药方面有其重要的用途,因而其产品价格在腐植酸类物质中为最高。…     

HPLC法测定不同施肥模式栽培的金线莲中黄酮类成分

HPLC法测定不同施肥模式栽培的金线莲中3种黄酮类成分:槲皮素、山奈酚和异鼠李素.超声-微波协同提取法提取4种不同施肥模式下金线莲中的黄酮类成分.HPLC-电喷雾离子化法/质谱(HPLC-ESI-MS)对黄酮类化合物进行定性分析.HPLC分析得槲皮素在0.25~20.0μg/m L(r=0.999 2)、山奈酚在0.25~20.0μg/m L(r=0.999 5)、异鼠李素在1.0~80.0μg/m L(r=0.999 0)范围内峰面积与浓度呈良好的线性关系,不同栽培方法的金线莲药材中槲皮素、山奈酚、异鼠李素的质量分数分别在151.8~240.0、47.2~88.2、16.8~29.8μg/g之间.方法简单、精确,快速,可为科学评价不同培养模式金线莲质量提供依据.栽培过程施加氮、磷、钾(NPK)复合肥及添加腐植素和微量元素,能提高金线莲中3种黄酮类成分的含量.栽培过程施加硫、磷(SP)复合肥,槲皮素、山奈酚和异鼠李素的质量分数分别下降了2.3%、17.2%和18.8%.结果表明采用不同施肥模式直接影响到药材中的药效物质的含量.     

电导滴定法快速测定钾的含量

１引言测定钾的含量常用火焰光度法和四苯硼钠重量法，火焰光度法适用于微量分析，四苯硼钠重量法的测定周期长。电导滴定法用于测定一些可发生沉淀反应的离子时，具有快速简便的优点。本文采用四苯硼钠溶液滴定，电导滴定法测定高、中含量组分钾的含量，测定周期仅需１０ｍｉｎ，所用试剂量少，不受样品中水不溶物的干扰，适用于钾盐、卤水和复合肥中钾的测定。２实验部分２．１仪器和药品电导率的测定采用ＤＤＳ－１２Ａ型数字式电导率仪和２１６型电导电极。四苯硼钠（Ｎａ［Ｂ（６Ｈ５）４］）为分析纯试剂，配成水溶液后用基准ＫＣＩ标…     

Theoretical Study on the Effects of Spatial Structure of P Complexation Sites on the Soil Phosphorus Activation in Leonardite Humic Acid Complexes

Humic acid is an important active component in soil environment. The spatial structures of P complexation sites in humic acid complexes play an important role in soil phosphorus activation and fertilizer efficiency. To explore the effects of spatial structure, the three different coordination modes of iron-carboxyl in models were calculated by the ONIOM method available in the Gaussian09 package. The(U)B3LYP hybrid density functional was employed to optimize the configuration for the QM region, and the UFF force field was used to calculate for the MM region. The results show that the different spatial structures influence the soil phosphorus activation by affecting the electronic structure, Gibbs free energy and interaction energy of the models. And the effects are as follows: the unidentate structure model ~6P-Fe-MHA-UD, the bidentate chelating structure model ~6P-Fe-MHA-BD>the bidentate bridging structure model ~5P-Fe-MHA-BD-BG. It can be known that, the fertilizer efficiency can be improved through increasing the proportion of the unidentate structure and the bidentate chelating structure in production engineering. The research provides a theoretical basis for further optimization of the production of humic acid phosphate fertilizer.     

Determination of Organic Compounds,Fulvic Acid,Humic Acid,and Humin in Peat and Sapropel Alkaline Extracts

Black, brown, and light peat and sapropel were analyzed as natural sources of organic and humic substances. These specific substances are applicable in industry, agriculture, the environment, and biomedicine with well-known and novel approaches. Analysis of the organic compounds fulvic acid, humic acid, and humin in different peat and sapropel extracts from Lithuania was performed in this study. The dominant organic compound was bis(tert-butyldimethylsilyl) carbonate, which varied from 6.90% to 25.68% in peat extracts. The highest mass fraction of malonic acid amide was in the sapropel extract; it varied from 12.44% to 26.84%. Significant amounts of acetohydroxamic, lactic, and glycolic acid derivatives were identified in peat and sapropel extracts. Comparing the two extraction methods, it was concluded that active maceration was more efficient than ultrasound extraction in yielding higher amounts of organic compounds. The highest amounts of fulvic acid (1%) and humic acid and humin (15.3%) were determined in pure brown peat samples. This research on humic substances is useful to characterize the peat of different origins, to develop possible aspects of standardization, and to describe potential of the chemical constituents.     

有机改性凹凸棒土对腐殖酸的吸附性能研究

合成了十六烷基三甲基氯化铵(CTAC)改性的凹凸棒土吸附剂,并研究了其对水中腐殖酸的吸附行为。通过FTIR、TG对改性前后凹凸棒土进行表征。结果表明,十六烷基三甲基氯化铵成功结合到凹凸棒土表面,结合到凹凸棒土表面的量为9.78%。在25℃时,腐殖酸在吸附剂上吸附行为符合Freundlich方程,吸附动力学符合拟二级动力学方程,初始浓度为54.60~200.20mg/L时,ATP-CTAC对腐殖酸的最大吸附量为253mg/g;温度对吸附行为影响不大;改性后的凹凸棒土对腐殖酸的吸附随pH的增大而降低;改性后的凹凸棒土显著地提高了对腐殖酸的吸附量。     

Syntheses of substituted-oxazolo-1,3,4-thiadiazoles, 1,3,4-oxadiazoles,and 1,2,4-triazoles

Starting from readily available methyl 5-methyloxazole-4-carboxylate ( 1 ) and 4-methyl-5-oxazolylcar-boxylic acid hydrazide ( 11 ) the title compounds were prepared. The reaction of compound 1 with hydrazine hydrate afforded the corresponding hydrazide 2 . The reaction of compound 2 with formic acid yielded 1-formyl-2-(5-methyloxazole-4-carboxyl)hydrazine ( 3 ). Refluxing of the latter with phosphorus pentasulfide in xylene gave compound 5 in 62% yield. The reaction of compound 3 with phosphorus pentoxide afforded compound 4 . Starting from hydrazide 11 , compounds 13 and 14 were prepared similarly. Reaction of compound 2 with substituted isothiocyanate yielded compound 9 which was cyclized in basic medium to 4-alkyl-5-(5-methyl-4-oxazolyl)-2,4-dihydro-3H-1,2,4-triazole-3-thione ( 10 ). The isomer 19 was prepared similarly. Methylation and subsequent oxidation of compound 19 gave compound 21 . Reaction of the acid 7 with thiosemicarbazide in the presence of phosphorus oxychloride gave 2-amino-5-(5-methyl-4-oxazolyl)1,3,4-thiadiazole ( 8 ). 2-Amino-5-(4-methyl-5-oxazolyl)-1,3,4-thiadiazole ( 17 ) was prepared from acyl chloride 15 by the usual method.     

New liquid chromatography columns for highlighting the interaction of ligand candidates with humic acid

Humic acid was the main compound in soil and reduced the availability of some organic compounds in soils. In this work, humic acid was immobilized for the first time on a homemade neutravidin poly(glycidyl methacrylate-co-ethylene dimethacrylate) capillary column with a 20 μm i.d. for the screening of potential ligands to humic acid and the evaluation of their molecular recognition mechanism. This homemade humic acid column enabling it to work at very low backpressure (0.60 MPa at 20 nl/min flow rate), had a long lifetime, excellent repeatability, and negligible non-specific binding sites. The performance of this affinity humic acid column was demonstrated by the evaluation of recognition assay for a series of known ligands of humic acid (a series of rodenticide molecules) which is the heart of the fragment-based drug design. In addition, this column was used successfully for highlighting the binding mechanism to humic acid of the severe acute respiratory syndrome coronavirus-2-spike protein. As well this new humic acid miniaturized liquid chromatography column developed in this work could be used in the feature for another solute molecule-humic acid binding studies or for a separative mode.     

土壤腐殖质各组分红外光谱研究

土壤腐殖质是土壤中所特有的一类特殊的高分子化合物,具有重要的肥力和环境调节功能。其中胡敏素的提取和纯化很困难,从而限制了对其性质和结构的研究。为揭示胡敏素的结构性质,本研究按Pallo分组,将胡敏酸(HA)分为焦磷酸钠提取的胡敏酸(HAP)、氢氧化钠提取的胡敏酸(HAS);富里酸(FA)分为焦磷酸钠提取的富里酸(FAP)和氢氧化钠提取的富里酸(FAS);胡敏素(HM)分为铁结合胡敏素(HMi)、粘粒结合胡敏素(HMc)和不溶性胡敏素(HMr)三个组分,采用红外光谱法对黑土、草甸土以及黑土底土加入大量玉米秸秆培养后腐殖质各组分的结构特征进行研究。腐殖质各组分按Pallo法分组。结果表明:铁结合胡敏素(HMi)、粘粒结合胡敏素(HMc)与胡敏酸(HA)、富里酸(FA)具有相似的光谱特征,但存在明显差异。黑土、草甸土中HMi和HMc的脂族性强于HA和FA;HMi与HMc相比,HMi具有较高的脂族性。黑土中氢氧化钠提取的胡敏酸(HAS)的脂族性强于焦磷酸钠提取的胡敏酸(HAP);NaOH提取的富里酸(FAS)的脂族性强于Na4P2O7提取的富里酸(FAP)。草甸土中HAP的脂族结构较多,而HAS脂族结构相对较少。在培养土中,新形成的FA脂族性强于HA、HMi和HMc组分。新形成的HMc脂族性强于HMi和HMc的脂族性强于HAP,而弱于HAS。     

胺基修饰大孔树脂对腐殖酸的吸附研究

研究了腐殖酸在胺基修饰大孔树脂D-301上的吸附行为,并与胺基修饰超高交联树脂NDA-99和大孔非极性树脂XAD-4作对比,结果表明,带有弱碱性基团的大孔亲水性树脂D-301对腐殖酸的吸附效果优于XAD-4和NDA-99,这主要得益于D-301树脂大孔结构和表面胺基修饰.探讨了溶液pH值和重金属离子对D-301树脂吸附腐殖酸的影响,并对作用机理进行了初步探讨.     

内蒙胜利褐煤腐殖酸对煤平衡复吸水的影响

研究了褐煤中重要的成分腐殖酸对褐煤水分的影响。测定了内蒙胜利褐煤中腐殖酸含氧官能团的含量,并分析了褐煤、棕黑腐殖酸和残余煤的等温吸附和脱附曲线。通过Dent吸附等温模型研究了褐煤和棕黑腐殖酸第一层吸附和第二层吸附。结果表明,胜利褐煤2/5羧基和1/5羟基是由腐殖酸提供的。棕黑腐殖酸相对褐煤孔径和孔容较小,不利于水簇的形成。腐殖酸对褐煤的复吸水是不利的     

Influence of humic substances on sorption and methylation processes of inorganic- and organo-tin species

The influence of humic substances on sorption and methylation processes for inorganic- and organotin species is presented. Four sediment samples from different locations of the Rivers Elbe, Mulde and Spittelwasser, Germany, with different organotin and humic contents were selected to extract the humic and fulvic acids. The various fractions—the original sediment, the humic acid, the fulvic acid and the residual sediment—were analysed for their organotin content. The individual buyltin species show quite different distribution patterns. Monobutyltin is found mostly associated with humic acids. Dibutyltin shows a nonunique behaviour. At low total organotin content, dibutyltin is found bonded to humic and fulvic acids, whereas at high organotin content dibutyltin is distributed more with the residual sediment. Most of the tributyltin remains in the sediment unextracted; only small quantities of it are in the fulvic acid fraction. Tetrabutyltin is only in the humic acid fraction when it binds to humic matter; it mostly remains in the sediment. General observations indicate that ionic butyltin species bind to fulvic acids whereas the non-polar tetrabutyltin is not found in the fulvic acid fractions in any of the samples. The appearance of monomethyl- and dimethyl-tin species in the humic and fulvic acid fractions after the alkaline extraction was surprising. There is a correlation between the humic content of the sample and the formation of methyltin species. Evidence is provided by experiments that humic substances act as methylation agents.     

Preparation and Properties of Novel Slow-release PK Agrochemical Formulations Based on Carboxymethylcellulose-Graft-Poly(acrylic acid-co-itaconic acid) Superabsorbents

To improve the utilization of fertilizer and water resources at the same time, a new slow-release PK compound fertilizer (SRCF) with the function of water retention was prepared. Element analysis results showed that the product contained 20.46% potassium (shown by K₂O) and 15.45% phosphorus (shown by P₂O₅), which were trapped in the matrix of carboxymethylcellulose-graft-poly(acrylic acid-co-itaconic acid) superabsorbent polymer. Major factors affecting the water absorbency of SRCF such as weight ratio of itaconic acid (IA) to acrylic acid (AA), contents of crosslinker, K₂HPO₄, and carboxymethylcellulose (CMC) were investigated and optimized. The water absorbency of the product was 130 times its own weight if it was allowed to swell in tap water at room temperature for 1 h. Fourier transform infrared spectroscopy (FTIR) and Thermogravimetric/Differential thermal analysis (TG/DTA) confirmed that AA and IA monomers were graft-copolymerized onto CMC backbone and presented the improved thermal stability. The water evaporation of the fertilizer-containing superabsorbents, as well as their nutrients release in sandy soil was carried out, and a possible slow-release mechanism was proposed. Additionally, compressive modulus measurements revealed that the introduction of CMC could improve the mechanical properties of the superabsorbents. These studies showed that the product with good slow-release and water retention properties, being economical and environment-friendly, could be expected to have wide potential applications in modern agriculture and horticulture.