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1.
ICP-AES法测定出口工业硅中11种杂质元素   总被引:2,自引:0,他引:2  
利用ICP-AES分析技术,对试样溶解方法,元素分析谱线,共存元素干扰,仪器分析参数,无机酸介质影响等因素进行了研究,确定了最佳工作条件,建立了可同时测定出口金属硅中11种杂质元素的简单、快速和适用的分析方法,结果表明,该方法线性范围宽,检出限低,准确性高,操作步骤简单,11个元素测定回收率在85%~105%之间,相对标准偏差在1.9%~8.1%之间。  相似文献   

2.
碱性氢化物发生—火焰原子吸收光谱法测定锡   总被引:7,自引:2,他引:7  
对Sn-NaOH-KBH4体系进行了系统研究,采用三乙醇胺-EDTA联合干扰抑制剂,可消除一定量铁及合金元素的干扰,对于锡含量小于0.01%的试样,用苯萃取锡后所有元素不干扰测定。测定液中锡量为0-4μg/10ml,呈线性关系,灵敏度为0.004mg/L/1%,检出限为0.008mg/L,测定钢中大于0.001%锡,结果满意。  相似文献   

3.
铁在端视ICP-AES中的光谱干扰与校正   总被引:2,自引:1,他引:2  
从信背比,干扰等效浓度,干扰校正因子几方面讨论了铁对多种元素的干扰,提出了干扰校正方法,用于实际样品测定,结果满意。  相似文献   

4.
氢化物发生ICP-AES法测定药用植物中的痕量锗   总被引:6,自引:0,他引:6  
本文应用氢化物发生ICP-AES法研究了药用植物样品中痕量锗的测定方法,系统地研究了ICP-AES仪器参数及氢化物发生条件对锗谱线信背比的影响,考察了13种共存元素的干扰,并比较了植物样品的3种前处理方法。选定H3PO4-HNO3-H2O2消化,在3mol/LH3PO4介质中,以15g/LNaBH4还原,测定药用植物样品中的锗,相对标准偏差≤2.9%,回收率为94%~103%。方法检出限达0.13μg/L。  相似文献   

5.
氢化物发生ICP—AES法测定药用植物中的痕量锗   总被引:4,自引:1,他引:4  
本文应用氢化物发生ICP-AES法研究了药用植物样品中痕量锗的测定方法,系统地研究了ICP-AES仪器参数及氢化物发生条件对锗谱线信背比的影响,考察了13种共存元素的干扰,并比较了植物样品的3种前处理方法,选定H3PO4-HNO3-H2O消化,在3mol/LH3PO4介质中,以15g/LNaBH4还原,测定药用植物样品可的锗,相对标准偏差≤2.9%,回收率为94%~103%,方法检出限达0.13μ  相似文献   

6.
隋喜云  王子树 《分析化学》1995,23(8):967-971
本文采用相对灵敏度因子,研究了99.999%-99.9999%的Ho2O3和Lu2O3中40余种杂质元素的火花源定量分析方法,讨论了谱线干扰。做了加入回收及生理性实验,大多数元素的相对标准偏差在30%以内,检测下限为0.00xμg/g。  相似文献   

7.
气相色谱法测定酯化反应液中的甲基丙烯酸甲酯及甲醇   总被引:3,自引:1,他引:2  
吴才玉  曾崇余 《色谱》1997,15(5):456-457
用正庚烷作内标物,10%PEG20M+1%NaOH/酸洗201红色担体作固定相,氢焰检测,对酯化反应液中的甲基丙烯酸甲酯(MMA)及甲醇进行定量分析。测得MMA和MeOH的校正因子分别为1.65和4.10,其相对误差分别小于1.5%和2.5%。方法便捷、可靠,值得推广应用。  相似文献   

8.
本文研究了一个简便,快速的用ICP-AESBi(Pb)SrCaCuPbO,Bi(Pb,Sb)Sr-CaCuO,Bi(Pb,Y)SrCaCuO超导体块材及薄膜中Bi,Pb,Sb,Y,Sr,Ca,Cu含量的方法。样品溶解在50%HCl及50%HNO3的混合酸中,直接引入等离子体光谱中进行测定。对共存元素的相互干扰及基片成分的干扰进行了研究。分析了大量样品,给出了各组分的挥发情况及Pb的挥发量与烧结温度  相似文献   

9.
赵进  王海舟 《分析化学》1996,24(3):264-268
本文研究了强酸性介质中,磷酸三丁酯萃取体系(TBP.HA)第三相的形成条件;探讨了TBP.HA对钛的萃取行为;建立了HClO4-H2SO4介质中,利用TBP.HA第三相萃取,然后用ICP-AES温室痕量钛的方法。结果表明,由于第三相体积小,对钛有较高的富集倍数,降低了分析的检出限,用ICP-AES检测,可以消除基体及其他大部分元素对测定的干扰,测定钛的回收率在97%-101%。利用本法对钢样标准物  相似文献   

10.
微分电位溶出法测定人发中铜铜镉锌的研究   总被引:5,自引:0,他引:5  
本文报道了0.0025mol.L^-1HCl-0.2mol.L^-1NH4Cl底液中连续测定人发中铜、铅、镉、锌的微分电位溶出法。四元素峰电位分别为-0.20V,-0.46V,-0.67V,-1.02V(SCE),峰形好,灵敏度高,干扰少,测定发样相对标准偏差≤4.3%,回收率为97.6%-104.6%。并对HNO3-HClO4和NHO3-H2O2消化发样进行了比较。  相似文献   

11.
The results of measurements of substituent induced chemical shifts of carboxyl carbons (deltaCO) of dichloro- and difluorobenzoic acids, including the monosubstituted ones with substituents at meta- and/or ortho- positions, in chloroform-d and strengths of these acids (log K) in chlorobenzene show an anomalous reverse trend between deltaCO and log K, while the electron density at carboxyl carbons should influence similarly both deltaCO and log K. A detailed chemometric analysis of comparison of disubstituent effects between deltaCO and log K on the basis of Fujita-Nishioka's multiparameter approach and assumption of additivity of substituent effects shows a dominance of the localized pi-polarization mechanism relative to simple electrostatic effects upon deltaCO. Further, steric factors play a significant role in determining deltaCO whereas with respect to log K they were insignificant. The overall anomaly has been rationalized keeping in mind that, while log K is a gross measure of energy differences between the ionized and unionized forms of the acids, deltaCO is a very sensitive probe for determining changes in electron density at the carboxyl carbon of the unionized acid.  相似文献   

12.
In the advanced Marfey's method, the resolution between the diastereomers derivatized with 1-fluoro-2,4-dinitrophenyl-5-l-leucinamide (l-FDLA) and 1-fluoro-2,4-dinitrophenyl-5-d-leucinamide (d-FDLA) is reflected by the difference of hydrophobicity of the two functional groups at the asymmetric carbon. However, no effective method has been developed for the estimation of hydrophobicity so far. For this purpose, we introduced log D from the ACD Labs LogD and applied it to relatively simple primary amines, amino acids and secondary alcohols in the present study. It was found that the difference of the retention times (ΔtR) correlated with that of log D (Δlog D) for both diastereomers based on the obtained experimental results. Based on these results, the following procedure was proposed for the non-empirical determination of the absolute configuration of primary amines including amino acids and secondary alcohols: (1) estimate the hydrophobicity by the calculation of log D for the two substituent groups at the asymmetric carbon, (2) locate the trans-type arrangement of the two more hydrophobic substituents in the l-DLA derivative and judge the asymmetric carbon to be R or S in the trans-type that is eluted first, (3) derivatize the desired compound with l- or d-FDLA and analyze by LC/MS, and (4) compare the elution order with the prospective one and determine the absolute configuration at the asymmetric carbon. Furthermore, log D could also be used to predict the retention times of unavailable amino acids and small peptides, indicating that the combination of the advanced Marfey's method with log D would provide more reliable structural information on a mixture composed of amino acids and small peptides. The developed method is being applied to more complicated compounds.  相似文献   

13.
刘小兰  高薇  梁超  乔俊琴  王康  练鸿振 《色谱》2021,39(11):1230-1238
反相液相色谱(RPLC)是测定正辛醇/水分配系数(log P)的有效方法,但由于缺少同类型模型化合物,RPLC在测定强离解化合物的log P时遇到挑战。该文在硅胶基质C18色谱柱上,采用离子抑制反相液相色谱(IS-RPLC)和离子对反相液相色谱(IP-RPLC)分别对中性化合物、酚酸、羧酸、磺酸及部分两性化合物的保留行为进行了系统研究。在IS-RPLC模式下,利用中性化合物、弱离解的酚酸和苯羧酸作为模型化合物,建立了表观正辛醇/水分配系数(log D)与纯水相保留因子对数值(log kw)的定量结构-保留行为关系(QSRR)模型,测定了19种离解化合物的log D值,作为后续IP-RPLC的模型化合物及验证化合物。在IP-RPLC模式下,将中性、弱离解和强离解化合物作为混合模型组,以溶质静电荷ne、氢键酸碱性参数AB为桥梁,建立了线性良好的log D-log kw-IP模型,采用3种不同类型的离解化合物进行了外部验证实验,预测值误差低于10%,证实了模型的可靠性。在此基础上,预测了8种强离解化合物的log D7.0值(pH 7.0条件下的log D值)。研究表明,利用结构相关参数沟通不同类型的模型化合物,是实现IP-RPLC测定强离解化合物log D值的一种行之有效的方法。与聚乙烯醇基质色谱柱相比,通用型的硅胶基质色谱柱上尽管存在着更多的次级作用,但可以为强离解化合物log D的测定提供更灵活的选择。  相似文献   

14.
A simple, quick, versatile and inexpensive HPLC method to estimate the logarithm of the octanol-water partition coefficient (log Pow) employing a methanol-water gradient and a short octadecyl-poly(vinyl alcohol) (ODP) column is described. This method is different from published HPLC-based log Pow methods because it uses retention times from a rapid methanol-water gradient to directly generate log Pow estimates, rather than from a series of isocratic mixtures extrapolated to 100% water. These HPLC log Pow values have good precision and correlate well with traditional shake-flask log Pow values. If necessary, the log Pow determination (including replications) can easily be carried out using only a milligram of sample. By suppressing ionization of acids and bases by the use of a buffer in the aqueous phase, the method can measure the log Pow of neutral organic molecules at any pH between 2 and 13. The method can be used with impure material and is rapid, 7 min per run and 4 min equilibration; it lends itself to and has been utilized for high-throughput hydrophobicity determinations (we have now carried out thousands of HPLC log Pow measurements by this method).  相似文献   

15.
Short-chain fatty acids are the major end products of bacterial metabolism in the large bowel. They derive mostly from the bacterial breakdown of carbohydrates and are known to have positive health benefits. Due to the biological relevance of these compounds it is important to develop efficient, cheap, fast, and sensitive analytical methods that enable the identification and quantification of the short-chain fatty acids in a large number of biological samples. In this study, a gas chromatography-mass spectrometry method was developed and validated for the analysis of short-chain fatty acids in faecal samples. These volatile compounds were extracted with ethyl acetate and 4-methyl valeric acid was used as an internal standard. No further cleanup, concentration, and derivatization steps were needed and the extract was directly injected onto the column. Recoveries ranged between 65 and 105%, and no matrix effects were observed. The proposed method has wide linear ranges, good inter- and intraday variability values (below 2.6 and 5.6%, respectively) and limits of detection between 0.49 μM (0.29 μg/g) and 4.31 μM (3.8 μg/g). The applicability of this analytical method was successfully tested in faecal samples from rats and humans.  相似文献   

16.
The iodous acid disproportionation is autocatalytic, and it is not easy to measure the rate constant of the step 2IO2H → IO3? + IOH + H+ separately. Hg(II) was used previously to suppress the autocatalytic pathway, but this method presents difficulties discussed in this work. A more effective method is the use of crotonic acid, an effective IOH scavenger. It suppresses side reactions, and a purely second‐order rate law is obtained. The rate constant decreases from 5 to 0.2 M?1 s?1 when the sulfuric acid concentration increases from 0.08 to 0.60 M. The observed decrease could be explained if IO2? reacts faster than IO2H. This may have consequences for the mechanism of the oscillating Bray–Liebhafsky reaction.  相似文献   

17.
The acid interferences in inductively coupled plasma atomic emission spectrometry (ICP OES) were studied in a multivariate way, considering the simultaneous presence of four mineral acids (hydrochloric, nitric, sulfuric and perchloric acid) with their concentrations ranging from 5 to 80% (w/w). A low power ICP OES was used, after optimization of operating parameters in order to achieve both plasma robustness and maximum signal to background ratios, favorable for trace element determinations in real samples. In order to investigate the interference mechanism, the combined effects of mineral acids on several parameters (solvent transport rate, analyte transport rate, excitation temperature, electron number density and magnesium ionic to atomic line intensity ratio) were evaluated and discussed. It was found that the combined effects of inorganic acids in ICP OES are, in general terms, more complex than the simple addition of the single effects. The more relevant interactions are between hydrochloric and nitric acids and those with sulfuric acid. Owing to these interactions, the resulting effects on the analytical signals are lower than the expected ones. The extent of any interaction depend on the nature of the interference. For the physical effects which are related with a change in the viscosity of the solution, an attenuation of the acid effect due to the presence of another acid at high concentration was evident. On the contrary, for the interferences related with a change in the plasma excitation conditions, the combined effects are higher than the addition of the single ones.  相似文献   

18.
In this study, graphitic carbon nitride deposited silica(g-C3N4@SiO2) was prepared by simple pyrolysis of melamine on silica and then used as a solid-phase extraction(SPE) sorbent for the extraction of four representative aromatic acids including benzoic acid(BA), salicylic acid(SA), indolyl-3-butyricacid(IBA) and naphthalene acetic acid(NAA) in coconut water(CW) samples. g-C3N4@SiO2 exhibited an excellent adsorption capacity for the four aromatic acids, which are in the concentration range of 500-558.8 μg/g. The four aromatic acids could be directly captured by g-C3N4@SiO2 from CW samples within 5 min. Thus, a rapid, simple and effective method for the analysis of four aromatic acids in CW samples was developed by coupling g-C3N4@SiO2-based SPE with high performance liquid chromatography-ultraviolet(HPLC-UV) detection. The linearity of the developed method was in the range of 20-1000 ng/mL and its limit of detection was in the range of 1.9-5.7 ng/mL, which were signi-ficantly lower than those of the reported similar methods. The intra-day and inter-day precisions(based on the relative standard deviation, n=3) of the four aromatic acids were under 9.5% and 10.4%, respectively. The developed method was applied to determining the four aromatic acids in real CW samples and the spiked recoveries varied from 81.1% to 121.8%.  相似文献   

19.
A capillary electrophoresis-mass spectrometry method was used to analyze naphthenic acids in produced water samples. It was possible to detect cyclopentanecarboxylic, benzoic, cyclohexanebutyric, 1-naphthoic, decanoic, 3,5-dimethyladamantane-1-carboxylic, 9-anthracenecarboxylic, and pentadecanoic acids within ca. 13 min using a buffer composed of 40 mmol/L ammonium hydroxide, 32 mmol/L acetic acid and 20% v/v isopropyl alcohol, pH 8.6. The proposed method showed good repeatability, with relative standard deviation (RSD) values of 6.6% for the sum of the peak areas and less than 2% for the analysis time. In the interday analysis, the RSD values for the sum of the peak areas and migration time were 10.3% and 10%, respectively. The developed method demonstrated linear behavior in the concentration range between 5 and 50 mg/L for benzoic, decanoic, 3,5-dimethyladamantane-1-carboxylic and 9-anthracenecarboxylic acids, and between 10 and 50 mg/L for cyclopentanecarboxylic, cyclohexanebutyric, 1- naphthoic, and pentadecanoic acids. The detection limits values ranged from 0.31 to 1.64 mg/L. Six produced water samples were analyzed and it was possible to identify and quantify cyclopentanecarboxylic, benzoic, cyclohexanebutyric, and decanoic acids. The concentrations varied between 4.8 and 98.9 mg/L, proving effective in the application of complex samples.  相似文献   

20.
The duplicate method for estimating uncertainty from measurement including sampling is presented in the Eurachem/CITAC guide. The applicability of this method as a tool for verifying sampling plans for mycotoxins was assessed in three case studies with aflatoxin B(1) in animal feedingstuffs. Aspects considered included strategies for obtaining samples from contaminated lots, assumptions about distributions, approaches for statistical analysis, log(10)-transformation of test data and applicability of uncertainty estimates. The results showed that when duplicate aggregate samples are formed by interpenetrating sampling, repeated measurements from a lot can be assumed to approximately follow a normal or lognormal distribution. Due to the large variation in toxin concentration between sampling targets and sometimes very large uncertainty arising from sampling and sample preparation (U(rel) ≥ 50%), estimation of uncertainty from log(10)-transformed data was found to be a more generally applicable approach than application of robust ANOVA.  相似文献   

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