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1.
准确快速测定土壤中的有效钼,是评价土壤肥力的重要指标,对指导作物生产有重大意义。本文采用草酸-草酸铵溶液浸提土壤样品,待测浸提液稀释5倍后通过电感耦合等离子体质谱法在氦气模式下测定土壤中有效钼的含量,建立了土壤中有效钼高灵敏度分析的检测方法。选择103Rh为内标元素,校正仪器在测定过程中引起的信号飘移。对两种前处理方式进行比较,确定了震荡30 min、放置过夜的浸提方法浸提效果更好且更利于大批量样品的分析。使用震荡30 min、放置过夜的浸提方法对5个土壤标准物质有效钼进行前处理,其测定值均在标准值范围内;分别在无气体模式和氦气模式下比较了浓度为0mg/L、1mg/L、2mg/L、5mg/L、10mg/L、50mg/L的Mn对5ug/L 95Mo测定浓度的影响,结果表明氦气模式下的动能歧视可有效去除95Mo测定过程中的多原子离子的干扰,氦气模式测定有效钼明显优于无气体模式;分别对待测溶液稀释5倍和未稀释的内标回收率趋势进行监测,发现未稀释的样品内标回收率随着测量样品数的增多呈下降趋势,而稀释5倍对基体干扰的消除有显著效果。对5个土壤样品分别重复测定6次,其RSD均小于4.1%;线性相关系数为1.0000;方法检出限为0.0012 mg/kg。综上,该方法测定土壤有效钼结果准确,重现性好,灵敏度高,且适合大批量样品的分析。  相似文献   

2.
先用磷酸溶解样品,后加入王水复溶,可同时测定锂、铍、钪、钒、铬、钴、镍、铜、锌、锗、钼、镉、钡、镧、铈、钨、铊、铅、钍和铀元素。研究了消解体系、ICP-MS的最佳测量模式和最佳工作状态,并以铑为内标校正仪器的漂移。通过选择高、中、低几个国家一级水系沉积物和土壤标准物质随同样品一起溶解建立标准曲线,消除消解、分取和定容时带来的不确定误差和基体干扰,选择8个土壤标准物质为实验样本。最终结果表明,方法准确度(Δlgc)小于0.1,精密度(RSD)小于8%,方法满足测定要求,适用于地质普通样品的多金属检测。  相似文献   

3.
为高效、准确、批量对土壤中多元素进行同时检测,本文通过改善消解模式、载气流速,优化了质谱条件,采用电感耦合等离子体串联质谱法(ICP-MS/MS)测定土壤中7种重金属元素。样品经王水预消解,氢氟酸+高氯酸+硝酸消解,以103Rh作为内标溶液消除基体干扰,在MS模式下通入氦气(即氦气模式),MS/MS模式下通入氧气(即氧气模式)消除质谱干扰的方式测定土壤中As、Pb、Cd、Cr、Ni、Cu、Zn 7种重金属元素。结果表明:当氦气流量为5.0mL/min,氧气流量为0.40mL/min时方法灵敏度和干扰消除效果最好。该方法的线性范围超过3个数量级,相关系数 r≥0.9999,检出限为0.01~1.00mg/kg,相对标准偏差(RSD)为1.5~10.2%。通过3个国家土壤一级标准物质(GBW07403a、GBW07404a、GBW07405a)对该方法进行了方法学验证,验证结果均在参考值范围内。  相似文献   

4.
在研究锗测定时,磷酸先溶解样品,后加入王水复溶,可同时测定锂、铍、钪、钒、铬、钴、镍、铜、锌、锗、钼、镉、钡、镧、铈、钨、铊、铅、钍和铀元素。研究ICP-MS的最佳测量模式、最佳工作状态,以铑为内标校正仪器的漂移。通过选择高、中、低几个国家一级水系沉积物和土壤标准物质随同样品一起实验溶解建立标准曲线,消除消解、分取、定容中带来的不确定误差和基体干扰,选择8个土壤标准物质为实验样本。最终结果表明,该实验方法准确度(ΔlgC)小于0.1,精密度(RSD)小于8%,该方法满足测定要求,适用于地质普通样品的多金属检测。#$NL  相似文献   

5.
土壤、沉积物系列标准物质中38种元素的ICP-MS定值   总被引:14,自引:0,他引:14  
探讨了电感耦合等离子体质谱测定土壤元素的基体效应及元素间的基体干扰,采用模拟土壤元素天然组成比值的校正溶液,利用^115In-^103Rh双内标校正系统有效地抑制了分析信号的动态漂移,建立了测定土壤中元素的ICP-MS方法;对GBW07410-07416土壤、沉积物系列标准物质进行定值,测定结果与XRF分析结果比较,同时用于GBW07404、GBW07405、GBW07408、GBW07309管理样分析,结果令人满意。  相似文献   

6.
有效钼是土壤质量评价不可缺少的指标,为准确高效测定土壤中的有效钼,样品采用Tamm溶液进行浸提,浸提液用5%(V/V)硝酸稀释10倍,利用电感耦合等离子体质谱仪(ICP-MS)碰撞模式,即KED模式下有效钼的测定,建立了标准曲线,标准曲线的相关系数为1.00,样品,确定分析元素钼的同位素95Mo,103Rh为内标,校正基体干扰和信号漂移,确定仪器分析参数等。该方法检出限(3σ)为0.002μg/L,对3个国家一级标准物质样品进行土壤中有效钼含量的平行分析,相对误差小于2%,相对标准偏差(RSD)小于5%,对200余件实际样品进行不同方法外检比对,合格率为98%。该方法具有操作简单、方便快捷,经济适用等特点,方法准确好、精密度高、再现性好,适合于各生产实验室各种类型土壤样品有效钼的大批量分析。  相似文献   

7.
建立了四酸消解-电感耦合等离子体质谱法测定土壤中铕(~(153)Eu)等24种稀有元素含量的分析方法。讨论了酸消解体系和消解过程对测定稀有元素存在的干扰,通过选择合适的待测同位素以及编辑干扰元素校正方程校正质谱干扰,采用嵌片技术和碰撞模式去除物理干扰和基体干扰;建立"主要干扰权重"概念,对内标元素进行分析筛选,最终确定~(185) Re、~(193)Ir作为内标元素。24种稀有元素标准曲线的线性相关系数均大于0.999,方法检出限为0.001~2.9mg·kg~(-1)。用3种土壤标准物质GSS-8、GSS-13、GSS-27进行精密度和准确度试验,相对标准偏差(n=6)为0.80%~19%,加标回收率为75.0%~128%,各元素的测定值均在认定值范围内。该方法适合在国家网土壤环境质量调查及其他相关工作和研究中推广和使用。  相似文献   

8.
基于HNO_3-HF-HCl酸消解体系,建立微波消解-电感耦合等离子体发射光谱(ICP-OES)法测定环境土壤中镧、铈、铷、锶4种元素的方法。利用恒定的氩气流作内标校正土壤基体干扰,采用径向观测+多重谱线拟合技术(MSF)校正光谱干扰,提升方法的检出限和精密度。结果表明,方法校准曲线r0.999,检出限在1.5~7.0μg/g,RSD在0.90%~5.7%,加标回收率83.0%~117%,用GSS-8、GSS-13标准样品验证,效果良好。  相似文献   

9.
基于HNO3-HF-HCl酸消解体系,建立微波消解-电感耦合等离子体发射光谱仪测定环境土壤中镧铈铷锶四种元素的方法。利用恒定的氩气流作内标校正土壤基体干扰,采用径向观测模式,利用多重谱线拟合技术(MSF)校正光谱干扰,提升本方法的检出限和精密度。结果表明:该方法校准曲线r>0.999,检出限在1.5~7.0 μg/g,RSD在0.9%~5.7%之间,加标回收率83.0%~117%,该方法用GSS-8、GSS-13标准样品验证,效果良好。  相似文献   

10.
利用微波消解仪消解土壤样品,采用电感藕合等离子体发射光谱仪测定土壤中硫的含量。以浓王水为消解试剂,对土壤样品进行微波消解,优化了王水用量,考察了微波消解条件、谱线干扰情况和仪器参数对硫灵敏度的影响。硫的质量浓度在0~40 mg/L范围内与光谱强度具有良好的线性关系,线性相关系数为0.9997,硫的检出限为0.053 mg/L。土壤中硫测定结果的相对标准偏差为1.54%~7.84%(n=7)。对六种土壤国家一级标准物质进行了测定,测定结果与推荐值相符,无显著性差异。该方法简便、准确,分析效率高,能够满足日常批量样品分析的要求。  相似文献   

11.
In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.  相似文献   

12.
KMnO4-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.  相似文献   

13.
The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.  相似文献   

14.
Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.  相似文献   

15.
The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.  相似文献   

16.
An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.  相似文献   

17.
A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.  相似文献   

18.
The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp3)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp2)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp2)?H and aliphatic 1,5- and 1,6-C(sp3)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp3)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp2)?H insertion.  相似文献   

19.
Zhanhui Yang  Shiyi Yang  Jiaxi Xu 《Tetrahedron》2017,73(23):3240-3248
Regiospecific and direct imidation of the methyl C(sp3)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.  相似文献   

20.
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