火焰原子吸收光谱法测定钒基合金中铬的含量

应用火焰原子吸收光谱法(FAAS)测定钒基合金(V-Cr-Ti三元合金)中铬的含量。取样0.100 0g,用硫酸(1+1)溶液5mL及硝酸2 mL加热溶解后蒸发至冒硫酸烟。冷却后移至100mL容量瓶中,加水定容。分取适量样品溶液(其中含Cr约为0.1～0.5mg)置于另一100mL容量瓶中,加入20g·L~(-1)硫酸钾溶液10mL(作为对共存元素V和Ti的抗干扰试剂,同时起到增敏作用明显提高信号强度),加水定容为100.0mL(溶液中含硫酸0.5%),按仪器工作条件测定溶液中铬的含量。在优化的试验条件下,铬的质量浓度在1.00～5.00mg·L~(-1)内与相应的吸光度之间呈线性关系。应用此方法测定了实际样品中铬的含量,测定值的相对标准偏差(n=6)为0.64%,以实际样品为基体,按照标准加入法在2个浓度水平上进行回收试验,测得回收率的平均值为97.1%。     

火焰原子吸收光谱法测定钴基合金中铁

钴基铸造耐磨合金是我所研制的一种新型耐磨合金材料 ,应用广泛 ,其合金成分为 w( C) 2 .0 %～3.0 % ;w( Cr) 2 3.0 %～ 2 8.0 % ;w( Mo) 3.0 %～5.0 % ,w( Fe)≤ 2 .0 % ,w( Co)为余量[1 ] 。快速、准确地测定合金中铁含量 ,对于有效地控制成分有十分重要的意义。由于钴与铁在化学性质上十分相似 ,因此 ,在用化学分析方法测量铁含量时 ,钴产生严重干扰 ,必需通过用氨水 -氯化铵沉淀分离出铁后 ,采用化学分析法或原子吸收光谱法进行测定 [2 ] ,分析操作十分繁琐 ,容易造成对分析精密度与准确度的影响 ,而且分析时间冗长。本文通过试验研究…     

氢氧化铁沉淀分离富集催化极谱法测定铅基合金中硒

探讨了５０μｇ以下的硒与氢氧化铁共沉淀的因素和分离铅基合金中硒的条件，从而成功地利用催化极谱法测定铅基合金中硒。分析范围在０．０５％－０．０００５％，回收率在９１．５％－１０５％间。应用于铅基合金中硒的测定，获得满意的结果。     

生物样品中痕量铬的直接快速极谱测定

1　引　　言微量铬的测定常用比色法和原子吸收分光光度法 ,但灵敏度不高。本实验为寻找一个灵敏、快速的测定痕量铬的新的极谱测定体系进行实验研究。结果表明 :在 0 .2 4mol/LNaNO2 4× 10 -5mol/L 2 ,2′ 联吡啶 1.6× 10 -5mol/L溴化十六烷基三甲铵 (CTMAB) (pH 8.0 )体系中 ,铬 在 - 1.39V(vs·SCE)附近有一灵敏、尖锐的二阶导数峰 ,其峰电流与Cr 浓度在 0～ 0 .0 2 0mg/L范围内有良好的线性关系。据此建立了测定生物样品猪肝及猪肾中痕量铬的简便方法。2　实验部分2 .1　仪器与试剂　JP 30 3型示波极谱仪 (成都仪器厂 ) ,…     

催化极谱法测定痕量铬的研究

本文研究了含氨介质中铬(Ⅲ、Ⅵ)-α,α’-联吡啶-亚硝酸钠体系的电化学行为。建立了测定痕最铬的方法。测定铬的范围为0.004～0.028μg/mL和0.04～0.23μg/mL,检测下限为2.0×10~(-3)μg/mL,用以测定生物样品中良量铬,变异系数为0.8%。     

看谱法测定铝合金的成分元素

研究了铝合金基体和合金中铝元素的看谱分析方法.对铝合金可见光谱线的激发方法及条件进行了试验探索.讨论了分析线和比较线的选取并摄制了相应的彩色图谱.结果可用于铝合金基体和合金中铝元素的定性和半定量看谱分析工作,能满足铝合金材料牌号鉴别的需求.     

硫酸亚铁铵滴定法测定铬铁矿中全铬含量

研究了硫酸亚铁铵滴定法测定铬铁矿中全铬含量的主要影响因素。采用过氧化钠碱融法分解试样,控制铬铁矿试样粒度在0.12mm以下,将试样置于600℃熔融12 min,在试样的硫磷混酸介质中,选择200g/L过硫酸铵溶液5ml,选择不使用硝酸银。采用硫酸亚铁铵滴定法测定不同品位的铬铁矿的全铬含量,测定结果的相对标准偏差（RSD,n=8）在 0.24%~0.34%之间,且与标准样品值相符。本方法操作流程简单,精密度和准确度能够满足铬铁矿中全铬含量的分析要求。     

微波消解样品-电感耦合等离子体原子发射光谱法分析铁基粉末合金

采用微波消解样品-电感耦合等离子体原子发射光谱法(ICP-AES)测定铁基粉末合金中的钙、钴、铬、铜、钼、钒及钨7种元素。试样用硝酸3mL和硫酸-磷酸-水(1+2+7)混合酸6mL溶解,于微波消解仪的密闭容器中,在功率800W及压力0.6MPa的条件下消解铁基粉末合金。试验选择各元素的分析线为317.993nm(钙),228.616nm(钴),205.552nm(铬),324.754nm(铜),204.598nm(钼),311.071nm(钒)及207.911nm(钨),配制工作曲线时采用基体匹配的方法消除基体干扰。为验证此方法的准确性,由3家分析实验室对3个样品用不同分析方法进行对比分析,结果表明:此方法的测定值与其他实验室的分析结果相一致。     

硫酸亚铁对化学沉积钴-铁-磷合金中的影响(英文)

在以次亚磷酸钠为还原剂、硼酸为缓冲剂和柠檬酸钠为络合剂的碱性介质中,化学沉积钴 铁 磷合金和钴 磷合金.研究了沉积工艺,如pH值和主盐CoSO4/FeSO4的摩尔比对沉积速率的影响.发现镀液中的硫酸亚铁对钴 铁 磷合金沉积有阻碍作用,以致其沉积速率比钴 磷的低.电化学极化实验表明,硫酸亚铁既影响阳极过程又影响阴极过程,它降低了两者的极化电流和极化电势.电化学实验结果与沉积速度测量结果基本相符.     

Persulfate Oxidation and Diphenylcarbazide Photometric Determination of Chromium in Super Alloys

The quantitative analysis of Cr in super alloys with the presence of a wide variety of elements, Al, B, C, Co, Cu, Hf, Fe, Mn, Mo, Ni, Nb, P, Si, S, Ti, Ta, W, Zr; and trace amounts (a few ppm) of Pb, Se, Bi, Tl and Te has been studied. Persulfate oxidation and diphenylcarbazide photometric method were studied with the purpose of developing a relatively fast and reliable measurement for Cr by wet chemical analysis. The results indicate that the latter is supperior to the former in practical view. In the photometric method, solid sample (0.1g alloys) when treated with HClO₄ and H₂SO₄ took ca. 72 hrs. for complete dissolution. When treated with HCl followed by HNO₃, 0.1 g alloys were completely dissolved within 1&1/2; hours. The best experimental conditions for diphenylcarbazide photometric determination of Cr was thus established. Photometric determination of Cr complexes was made at 540 nm.     

Voltammetric and Spectroscopic Study of Chromium(III)/Picolinate Complexes

The electrochemical properties and the stability of the Cr^III complexes [Cr(pic)₃]·H₂O and [Cr(pic)₂(OH)]₂·5H₂O (Hpic = pyridine‐2‐carboxylic acid = picolinic acid) were investigated in DMF solutions by cyclic voltammetry, and complemented by electronic spectroscopy. The electrochemical results indicate that both compounds undergo a one‐electron reversible reduction process. The mononuclear species has a more accessible reduction potential than the binuclear one. In this last case, the observed one‐electron process can be ascribed to a considerable stabilization of the mixed valence Cr^III/Cr^II species. Both complexes were also characterized by infrared and Raman spectroscopy.     

Spectroscopic, Chromatographic and Visual Investigation of Organic Dyes

An introductory level laboratory experiment is presented in which students learn about color using spectroscopy and chromatography. The pedagogical approach is discovery-based; students are given only enough background information to enable them to take good data. Commercially available dyes are dissolved in water to make concentrated stock solutions, which students then dilute to prepare solutions of primary, secondary and tertiary colors. The class works as a team to study colored solutions representing a range of concentrations and combinations of the three primary colors: cyan, yellow, and magenta. Students record transmission and absorption spectra and compare the results with human perception. They show the number of components in each solution by paper chromatography. They explore the filter nature of dyes, the effects of concentration, and the cumulative effects of mixing dyes. From this information they deduce the principles of color printing.The experiment is best performed with a photodiode array spectrophotometer; alternative approaches include spectrometers and simple spectroscopes which the students make from cereal boxes. The experiment can be performed in either a single three-hour laboratory period, or alternatively, three one-hour sessions.     

高氯酸处理-亚铁滴定法快速测定钢铁中铬钒

提出了一种高氯酸处理、硫酸亚铁铵滴定法快速测定钢铁中铬钒的方法。高氯酸溶解样品,并冒高氯酸烟至锥形瓶瓶口5～10 s,在稀硫酸-磷酸混合酸中,以苯代邻氨基苯甲酸为指示剂,硫酸亚铁铵溶液滴定铬(Ⅵ)、钒(Ⅴ)合量。不分解指示剂,在亚砷酸钠存在下,直接用高锰酸钾选择性氧化钒(Ⅳ),尿素存在下,亚硝酸钠还原过量氧化剂,硫酸亚铁铵溶液滴定钒(Ⅴ)。测钒时,指示剂无校正值。并讨论样品处理方法、亚砷酸钠对高锰酸钾用量的缓冲作用以及对亚硝酸钠用量的拉平效应。方法快速、简便、准确、实用,选择性好。     

Two-Phase Aqueous Extraction of Chromium and its Application to Speciation Analysis of Chromium in Plasma

 This work proposes a new extraction method for chromium based on the two-phase aqueous system isopropyl alcohol-ammonium sulfate-ammonium thiocyanate (i-PrOH-(NH₄)₂SO₄-NH₄SCN), and the related experimental conditions are optimized. The results show that chromium (III) can be quantitatively extracted under the selected conditions: 4 mL of i-PrOH, 200 μL of 2 mol/L sulfuric acid, 1 mL of 4 mol/L NH₄SCN and 3 mL of saturated (NH₄)₂SO₄ solution (V_total=10 mL). Application of the proposed method to speciation analysis of plasma chromium was also investigated and satisfactory results were obtained. Received May 22, 1999. Revision November 8, 1999.     

过硫酸铵氧化可视滴定法测定低合金钢中铬含量的不确定度评定

依据测量不确定度的评定原理和方法,对GB/T 223.11–2008过硫酸铵氧化可视滴定法测定低合金钢中铬含量的测定结果不确定度分量来源进行分析和合理评估。当测试样品中铬含量为0.736%时,其扩展不确定度为0.006 2%(包含因子k=2)。