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紫外-可见吸光光度法同时测定铬(Ⅲ)和铬(Ⅵ) 总被引:5,自引:0,他引:5
关于铬 (Ⅲ )和铬 (Ⅵ )测定有若干报道 ,但大多数是分离后分别进行测定[1,2 ] ,或先测定出铬 (Ⅲ )或者铬 (Ⅵ ) ,然后通过氧化或还原测出铬的总量 ,再用差减法求出另一个价态铬的含量[3 ] ,这些方法比较麻烦 ,且在处理过程中易导致价态的改变 ,文献 [4]曾研究利用铬 (Ⅲ )与EDTA反应 ,可在铬 (Ⅲ )存在下光度法测定铬 (Ⅵ ) ,并指出同时测定铬 (Ⅲ )和铬(Ⅵ )的可能。文献 [5 ]也对此进行了研究 ,采用先进仪器 ,用最小二乘法 ,建立了多元校正 紫外 可见吸光光度法同时测定铬 (Ⅲ )和铬 (Ⅵ )的方法。此法虽解决了吸收光谱重叠问题 ,… 相似文献
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光度法在铬(Ⅵ)测定中的研究进展 总被引:2,自引:0,他引:2
论述了2006~2009年光度法在铬(Ⅵ)测定中的研究进展.现今测定铬(Ⅵ)的光度法主要包括吸光光度法、催化动力学光度法、荧光光度法和原子吸收光谱法.近年来,人们开始关注流动注射光度法和共振光散射光谱法.这2种光度法在铬(Ⅵ)的测定分析中克服了传统方法的试剂稳定性差、选择性较差等缺点.具有灵敏度高、选择性好、试剂消耗量少和分析速度快等优点.随着分析方法的改进创新和新技术的应用,铬(Ⅵ)光度分析方法将逐步向高灵敏度、高选择性和自动化方向发展. 相似文献
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流动注射-火焰原子吸收光谱法测定水样中铬(Ⅲ)和铬(Ⅵ) 总被引:1,自引:0,他引:1
应用编结反应器(KR)在线富集,提出了测定水样中痕量铬(Ⅲ)和铬(Ⅵ)的流动注射-火焰原子吸收光谱法。取2份水样与络合剂吡咯烷二硫代氨基甲酸铵(APDC)溶液在线混合,分别与样品中铬(Ⅲ)及铬(Ⅵ)形成络合物并吸附于KR的内壁上,引入空气除去残留的溶液。泵入乙醇-盐酸(9+1)混合溶液将吸附于KR内壁上的络合物洗脱。按仪器工作条件测定洗脱液的吸光度(A_s)。另取1份水样,预先用抗坏血酸将其中铬(Ⅵ)还原为铬(Ⅲ),再按上述条件操作并测得吸光度(A_(Cr))。基于铬(Ⅲ)和铬(Ⅵ)富集系数的差异,推导了铬(Ⅲ)及铬(Ⅵ)含量的计算公式,将所测数据代入公式进行计算。所提出方法对铬(Ⅲ)及铬(Ⅵ)的检出限(3S/N)依次为8.9,5.3μg·L~(-1),相对标准偏差(n=5)分别为5.6%和2.8%。用标准加入法测得回收率在95.9%~98.9%之间。 相似文献
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流动注射在线富集分离-火焰原子吸收光谱法测定水体中的铬(Ⅲ)和铬(Ⅵ) 总被引:4,自引:0,他引:4
内装活性氧化铝(碱式)和阴离子交换树脂的微型柱流动注射在线富集分离水体中的铬(Ⅲ)和铬(Ⅵ),火焰原子吸收法直接检测。微型住可同时富集两种价态的离子,分别用1mol/L的NH4NO3和HNO3洗脱Cr(Ⅵ)和Cr(Ⅲ)于喷雾器中。进样时间25s,铬(Ⅵ)和铬(Ⅲ)的富集倍数分别为11倍和20倍,实际水样的加标回收率在90%~106%之间;分析速率为50个样/h;铬(Ⅵ)、铬(Ⅲ)的检出限(3δ)分别为1.5μg/L和0.7μg/L;相对标准偏差(50μg/L)分别为1.9%和2.6%。 相似文献
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价态铬的测定有多种方法。其中有的灵敏度较低,有的设备昂贵,而且一般都要预先对铬(Ⅲ)和铬(Ⅵ)进行分离富集,分析过程比较复杂。本文在前人工作基础上对水体中价态铬的液相化学发光分析法进行实验,此法依据的原理是:在碱性水溶液中,自由铬(Ⅲ)离子可以催化鲁米诺-过氧化氢体系的 相似文献
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具有铁磁偶合的新型草酸根桥联Cu(Ⅱ)-Cr(Ⅲ)-Cu(Ⅱ)三核配合物 总被引:4,自引:0,他引:4
合成和表征了两种新的异三核配合物,[Cu~2(phen)~2Cr(OX)~3NO~3]和[Cu~2(Mebpy)~2Cr(OX)~3]NO~3(phen表示1,10-邻菲咯啉,Mebpy表示4,4'-二甲基-2,2-联吡啶,OX表示草酸根阴离子).基于变温磁化率测量(4.2~300K)和自旋哈密顿算符H=-2J(S~C~u~1·S~C~r+S~C~u~2·S~C~r)已推出交换积分J=35.18cm^-^1(Mebpy) 和J=30.24cm^-^1(phen),表明配合物中Cu(Ⅱ)和Cr(Ⅲ)离子间为铁磁偶合 相似文献
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在4000-100cm^-^1波段范围内测定了含μ3-O三核混合铁铬醋酸配合物[FeCr2(μ3-O)(μ-O2CCH3)6(H2O)3]·NO3·xH2O和[Fe2Cr(μ3-O)-(μ-O2CCH3)6(H2O)3]·NO3·xH2O的红外光谱。采用简化的普遍价力场对它们简化的骨架模型FeCr2O16和Fe2CrO16进行了简正坐标分析。振动基频的计算值与观测值符合良好, 两者平均偏差无小于1.50%。计算结果支持了振动谱带的归属和精修的力常数的合理性。 相似文献
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离子缔合型离子选择电极的研究 I: PVC膜铬(VI)离子选择电极的研制的和应用 总被引:3,自引:0,他引:3
A new Cr(VI)-selective electrode of PVC membrane based on triheptyl dodecyl ammonium iodide is described. The response of the electrode is Nernstian for Cr(VI) concentration down to 2X10-6M in 0.03-0.13N HF solution. Limit of detection is 5X10-7M. The plot of logarithms of selectivity coefficients vs. z/γ of various anions is essentially linear with a correlation coefficient of -- 0.88. Applications of the electrode in determination of total Cr in steels and copper alloys, and Cr(VI) in waste-water from chromium electroplating are reported. 相似文献
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Cr^3^+的水解聚合作用IV.两种"根+节"体系之间的过渡状态 总被引:1,自引:0,他引:1
The hydrolytic polymerization of chromium (III) ion in 0.040, 0.060, 0.080 and 0.160M Cr(NO3)3 solutions was studied pH-metrically in the medium of 0.5M NaNO3 at 40+/-1 C. The average number of OH- bound per Cr^3^+ at different pH was designated as Z, the gighest value of Z was found to be about 1.0. A family of curves of Z(pH)B, each at a definite concentration B of Cr(NO3)3, was obtained. The values of both B and pH were determined from the curves and a linear relationship between -lgB and pH was found for each value of Z. From the slope of each curve of-lgB(pH)z, a value of t was obtained, which increased from 1.51 to 2.06 when Z increased from 0.10 to 1.0. This implied that the polymerized hudrolysis products were of mixed types. The data of different Z value were treated by three different methods, namely, "core + links" method, project strip method and "homoligand formation constant" method. The results obtained showed the existence of "core + links" compounds not only with two hydroxyl bridges as Cr (Cr(OH)2)n^(^3^+^n^)^+(n = 1,2,3) but also with both one and two hydroxy bridges as Cr3(OH)3, indicating that the present system was a transition from t = 2 to t = 1. The hydrolysis constants of the above compounds are as follows: lgβ = -4.19, lgβ33 = -5.28, lgβ = -8.23, lgβ64 = 12.28. The above results are in agreement with those obtained at low and medium concentration of Cr(NO3)3. Furthermore, the constants obtained by means of different methods are in good agreement with each other as well as with those reported in previous papers. 相似文献
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《Analytical letters》2012,45(8):1447-1451
Abstract A fluorescence quenching method for the determination of Cr(VI) in aqueous solution is described. The fluorescence intensity of the system is linear ever the range 5×10?6 - 1.0×10?4 M Cr(VI). The method has been applied to the determination of Cr(VI) In cast iron and waste water. 相似文献
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借4-(2-噻唑偶氮)间苯二酚螯合物和反相高压液相色谱法以分离和测定钒、钴和铬 总被引:4,自引:0,他引:4
研究了V(V)、Co(II)和Cr(III)的TAB螯合物的柱前衍生条件和反相高压液相色谱分离条件, 并提出了同时测定ppb级的此三元素的新方法。于Zorbax ODS柱上,用含0.05mol.dm^-^3Li2SO4和0.01mol.dm^-^3HOAc-NaOAc(pH6.0)的46:54甲醇-水(v/v)溶液作流动相(0.7mL/min), 可于15min内将此三螯合物分离并检测(525nm)完毕。此方法快速、经济、灵敏选择性好。 相似文献