Cu（Ⅱ）-H2O2-考马斯亮蓝G250体系催化光度法测定痕量铜

在NH3-NH4Cl缓冲溶液介质中,痕量Cu2+对H2O2氧化考马斯亮蓝G250(CBBG)褪色反应的显著催化作用,建立了催化动力学光度法测定痕量铜的新方法。线性范围为0.02～0.20μg/mL,检出限为1.34×10-9g/mL。考察了20多种共存离子的影响。方法用于发样中痕量铜离子的测定,相对标准偏差小于3.4%,加标回收率为97%～105%。     

应用手持式XRF分析仪快速测定白铜中的Cu、Ni、Co含量

采用国产手持式XRF分析仪快速分析了白铜合金主元素的含量,探讨了白铜合金基体效应对测量结果的影响,采用经验系数法中多元回归分析建立数学模型,较好地校正基体效应,分析白铜合金中铜、镍、钴的平均相对误差分别为0.39%、1.83%、1.59%。     

Determination of barium,copper and yttrium in superconductor materials by inductively coupled plasma/atomic emission spectrometry

Barium, copper and yttrium (or a rare earth element) in superconductor and related materials were determined by inductively coupled plasma/atomic emission spectrometry. Relative standard deviations of repeated determinations were about 2%. The results obtained with this method agree within 2% (average relative deviation) of those obtained with chemical methods.     

选矿废水中铜铁含量连续滴定

本文针对选矿废水中的铜离子和铁离子,在滴定铜离子含量的基础上,向滴定液中继续加入三氯化铝溶液作为解蔽剂将铁离子解蔽,此时溶液呈深棕色,以硫代硫酸钠标准溶液继续滴定铁,溶液深棕色消失转为奶白色即为滴定终点,本法避免了单独滴定铜铁含量的麻烦,且在滴定铁离子含量时无需除铜。经实验验证,应用本法对选矿废水中铁含量进行滴定与重铬酸钾滴定铁含量的结果一致,相对误差小于2.03%,加标回收率在95.80%-101.9%之间,相对标准偏差(RSD,n=10)在0.48%-1.52%之间。本方法精密度高,重现性好,简便快捷,可以满足选矿废水中铜、铁含量的滴定要求。     

X-ray fluorescence spectrometry of copper intermediates

Iron, magnetite, copper, copper(II) oxide, calcium carbonate, sulphur, silicon dioxide and aluminium oxide as components of copper intermediates (concentrates, slags, mattes, calcines and fluxes) in powdered (300-400 mesh) binary mixtures obey the Lachance-Traill equation, so the coefficients alpha(AX) of interelement effects can easily be determined experimentally. They show a reasonable agreement with the theoretical values calculated from mass absorption coefficients. This fact can be the basis of a convenient routine method for the determination of intermediates. Since the intermediates exhibit differences in the distribution of their atoms (microcosmic inhomogeneity) a correction factor k(dist) has to be used. Its value for the main components (concentrations > 5%) is in the range 0.92-1.24 The highest relative average deviation of the results from those of the classical "wet" methods is 2.7% for the major and 30% for the minor components.     

A simple and very sensitive spectrophotometric method for the direct determination of copper ions

A sensitive spectrophotometric method for the direct determination of copper in aqueous samples without a preconcentration step has been developed. It is based on the formation of a yellow complex with the chromogenic reagent di-2-pyridyl ketone benzoylhydrazone (dPKBH) in an alkaline medium. The complex stoichiometry was 1:2 (Cu:dPKBH) and presents maximum absorbance at 370 nm. The influence of chemical variables affecting the behaviour of the system such as pH, concentration of dPKBH, buffer solution and ethanol, order of addition of the reagents and stability of the complex, were evaluated. The molar absorptivity (epsilon) was 3.92x10(4) L mol(-1) cm(-1), and Beer's law was obeyed up to 3 mg L(-1) of copper. The relative standard deviation was 0.46% (n=11) for a sample containing 1 mg L(-1) Cu(II). The limit of detection was 2.5 micro g L(-1) and was therefore more sensitive than the direct methods reported previously. Finally, the method was successfully validated by analysing several real samples with different matrices, such as tap water, natural water or copper alloys, with an average relative error of 2.46%.     

碘量法连续测定选矿废水中的铜铁

针对选矿废水中的铜离子和铁离子,在滴定铜离子含量的基础上,向滴定液中继续加入三氯化铝溶液作为解蔽剂将铁离子解蔽,此时溶液呈深棕色,以硫代硫酸钠标准溶液继续滴定铁,溶液深棕色消失转为奶白色即为滴定终点,避免了单独滴定铜铁含量的麻烦,且在滴定铁离子含量时无需除铜。经实验验证,对选矿废水中铁含量进行滴定与重铬酸钾滴定铁含量的结果一致,相对误差小于2.03%,加标回收率在95.8%~101.9%,相对标准偏差(RSD,n=10)在0.48%~1.5%。方法精密度高,重现性好,简便快捷,可以满足选矿废水中铜、铁含量的测定要求。     

超声波萃取-SPE净化-双柱双检测器测定土壤和沉积物中的20种有机氯

建立了超声波萃取-SPE硅胶小柱净化-双柱双检测器气相色谱法测定土壤和沉积物中20种有机氯农药的方法。样品中添加高纯铜粉除硫,二氯甲烷超声萃取9 min,使用SPE硅胶小柱,9 mL丙酮:正己烷(1:9)洗脱净化。采用单进样口,双色谱柱双μ-ECD同时分离测定。土壤和沉积物样品中的方法检出限为0.001 mg/kg,平均回收率为73.17%～112.5%,相对标准偏差为0.33%～16%。     

塞曼火焰原子吸收光谱法直接快速测定白砂糖中的铜及铅含量

采用标准加入法,消除了基体,背景和粘度的影响,直接用塞曼火焰原子吸收光谱法测定白砂糖中的铜及铅含量。此法具有简便、快速、灵敏度高等优点,相对标准偏差铜为０．６１％－１．９％,铅为０．９４％－３．５％;回收率铜为９８．４％－１０２％,铅为９７．４％－１０４％。     

Selective kinetic spectrophotometric determination of copper at nanograms per milliliter level

A sensitive and selective kinetic method is proposed for the determination of nanogram amounts of copper. The method is based on the catalytic effect of copper on the reduction of Ponceau S by sodium sulfide in an alkaline media. The rate of the reaction is monitored spectrophotometrically at 560 nm. The method allows determination of copper concentrations in the range 2-400 ng ml(-1) with a relative standard deviation of approximately 2%. The proposed method, which is highly selective to copper, has been applied satisfactory to its determination in real samples.     

碘量法测定废杂铜屑中的铜含量

采用硝酸-盐酸溶解样品,在硫酸体系下加入氢溴酸,使得氢溴酸与试样中的砷、锑、锡等元素反应生成易挥发的溴化物,从而消除其干扰,滴定前用氟化氢氨掩蔽铁,在pH=3.0～4.0的范围采用碘量法测定废杂铜屑中的铜含量。用于测定金属样废杂铜屑中铜的含量,测定结果的相对标准偏差(RSD,n=7)为0.20%～0.25%,加标回收率在98.8%～101%,方法简单准确,能够满足日常检测需求。     

A partial least squares based spectrum normalization method for uncertainty reduction for laser-induced breakdown spectroscopy measurements

A bottleneck of the wide commercial application of laser-induced breakdown spectroscopy (LIBS) technology is its relatively high measurement uncertainty. A partial least squares (PLS) based normalization method was proposed to improve pulse-to-pulse measurement precision for LIBS based on our previous spectrum standardization method. The proposed model utilized multi-line spectral information of the measured element and characterized the signal fluctuations due to the variation of plasma characteristic parameters (plasma temperature, electron number density, and total number density) for signal uncertainty reduction. The model was validated by the application of copper concentration prediction in 29 brass alloy samples. The results demonstrated an improvement on both measurement precision and accuracy over the generally applied normalization as well as our previously proposed simplified spectrum standardization method. The average relative standard deviation (RSD), average of the standard error (error bar), the coefficient of determination (R²), the root-mean-square error of prediction (RMSEP), and average value of the maximum relative error (MRE) were 1.80%, 0.23%, 0.992, 1.30%, and 5.23%, respectively, while those for the generally applied spectral area normalization were 3.72%, 0.71%, 0.973, 1.98%, and 14.92%, respectively.     

A simple potentiometric method for the determination of reducing substances in urine with a copper-selective electrode

A potentiometric method for the determination of reducing substances in urine is described. Samples are treated with Stanley—Benedict reagent and the unused copper(II) is determined with a copper(II)-selective electrode by the standard addition technique. Glucose in the range 25–200 μg in 0.1ml samples can be determined with an average error of about 2%. The recovery of added glucose for six samples was 96–107% (average 100.5%). Comparison with the conventional titrimetric method shows good agreement. The effect of other non-glucose reducing substances present in urine is reported.     

硅藻土吸附在线柱富集-火焰原子吸收光谱法测定环境水样中痕量铜

提出了硅藻土吸附在线柱富集-火焰原子吸收光谱法测定环境水样中痕量铜的方法。利用硅藻土对环境水样中痕量铜在线预富集,浓集因子达到27.6,使火焰原子吸收光谱法的检测能力达到测定环境水样中痕量铜的要求。方法检出限为0.32μg.L-1,RSD(20μg.L-1)为3.52%,加标回收率为97.0%~105.0%。     

Na2EDTA滴定法测定铜冶炼烟尘中铋含量

研究了测定铜冶炼烟尘中铋含量的Na_2EDTA络合滴定方法。对测定体系中的各干扰元素进行了研究,探讨了测定方法的各项测定条件。方法的相对标准偏差为0.40%～0.67%,样品加标回收率在99.9%～100%,方法精密度高,准确度好。适用于铜冶炼烟尘中铋含量为5.00%～16.00%的测定。     

火焰原子吸收光谱法测定铜冶炼烟尘中铋

本文研究了测定铜冶炼烟尘中铋含量0.050% ~5.00%的火焰原子吸收光谱法。对铜冶炼烟尘试样的溶解、测定体系中酸介质的影响和各干扰元素进行了试验研究。制定了铜冶炼烟尘中铋含量的原子吸收光谱法。方法标准偏差为0.0013 %~ 0.057 %,相对标准偏差为0.78 % ~1.44 %,样品加标回收率为98.95%~101.87%。本方法具有灵敏度高、结果准确、操作简便等特点,适合铜冶炼烟尘中铋含量0.050 % ~ 5.00 % 的测定。     

Determination of bismuth,lead and tellurium in copper by atomic absorption spectrometry with introduction of solid samples into an induction furnace

Atomic absorption spectrometry with an induction furnace is used for the determination of bismuth (0.015–10 μg g^-1), lead (0.2–15 μg g^-1) and tellurium (0.04–5 μg g^-1) in 2–30-mg samples of copper and low-alloy copper dropped into the furnace. Calibration graphs of peak area versus mass of element were constructed by use of standardised alloys. The accuracy, precision and limits of detection of the method are described for numerous copper samples. With alloys containing more than 0.1 μg Bi g^-1, 0.2 μg Pb g^-1 and 0.8 μg Te g^-1, average relative standard deviations are 7%, 6% and 8%, respectively. The limits of detection for bismuth, lead and tellurium are 0.01, 0.1 and 0.02 μg g^-1, respectively.     

连续滴定法测定铅精矿中的铅、铜

建立了铅精矿中主量元素铅和次量元素铜的连续滴定分析方法。将铅滴定分析中经硫酸沉淀分离后的滤液,再经硫酸冒烟,用去离子水溶解后,通过滴定法对铅精矿中高含量铜进行分析。该方法铅精矿中铅的检出限为1.4 mg/g,铜的检出限为1.0 mg/g。对3个实际样品中铅、铜分别进行测定,测定结果的相对标准偏差均小于3.0%(n=7),铅的加标回收率为99.71%~100.19%,铜的加标回收率为99.33%~100.47%。该方法通过一次溶样,对铅精矿中的铅、铜连续进行滴定分析,方法快速、准确,适用于铅精矿中含量大于1.4%的铅和含量大于1.0%的铜的测定。     

Determination of Cu(III) and Cu(II) + Cu(III) in superconducting copper ceramics

Summary Copper(III) and total copper in superconducting Y-Ba-Cu oxide and related compounds can be determinated by two successive iodimetric titrations after the sample has been dissolved under Ar in HCl/KI medium. First, the iodine equivalent to copper(III) ist titrated with Na₂S₂O₃ solution at pH 4.8, copper(II) being masked with EDTA. The total copper is then determined in the same solution by demasking with acid and iodide, followed by iodimetric titration. The method is both accurate and reproducible. The relative standard deviations for 1.074% copper(III) and 23.37% total copper are 0.8% and 0.3%, respectively.     

Spectrophotometric determination of trace copper in water samples with thiomichlersketone

A simple and sensitive spectrophotometric method for determination of trace copper in water samples is proposed. In the presence of pH 4.6 HAc-NaAc buffer solution and surfactant polyethylene octyl phenyl ether (OP) medium, copper reacts with thiomichlersketone (TMK) to form a stable 1:4 complex. The complex Cu(II)-TMK-OP shows maximum absorbance at 500 nm with a molar absorptivity value of 5.7x10(4) l mol-1 cm-1. Beer's law is obeyed for copper concentrations in the range of 0-15 microg/25 ml. The average recovery of copper is between 95.8 and 106%. The method has been applied for determination of trace copper in different water samples with satisfactory results.