三元配合物薄层树脂相光度法测定天然水中痕量钴的研究

在酸性条件下(pH 5), 利用阳离子交换树脂-丁二酮肟-碘-钴四元体系, 在454 nm处具有最大吸收, 确定了借助薄层树脂相光度法测定钴的新方法.本法灵敏度高(ε454=1.7×105 L·mol-1·cm-1), 比水相光度法提高14倍, 精密度高(测定2.0 μg/mL Co(Ⅱ) 6次, RSD=1.3%), 选择性好. 实测天然水中钴,线性范围0.024～2.0 μg/mL, 检出限10.4 ng/mL.     

离子交换树脂相分光光度法测定水中痕量铋

利用离子交换树脂相通过光度法测定痕量铋。铋离子在碱性介质中与邻苯二酚紫形成紫色络合物将其富集在苯乙烯阴离子交换树脂上,通过制作成薄层直接光度法测定。本法操作简便,装皿容易,选择性好,精密度高(测定5μgBi3 5次,RSD=3.8%),铋浓度在0~10μg(50ml)时与吸光度呈线性关系,线性回归方程为A=0.010 0.075C(μg/50ml),相关系数r=0.9997,铋的回收率为98%~99%,检出限为3.2μg/L,用于水中痕量铋的测定,结果满意。     

薄层树脂相吸光光度法测定痕量钼的研究

在酸性条件下,建立了以薄层树脂相吸光光度法测定钼的新方法。此法灵敏度高 (402=1.0×105L/molcm),比水相光度法提高24倍 (水相= 4.2×103L/molcm),精密度好 (检测6次,RSD=1.21%)。工作曲线线性范围 (25ml体积) 0~18g,测定天然水中钼,加标回收率为95%~105%。     

离子交换树脂预富集与分光光度法联用测定高纯稀土中的痕量硅

在强酸性条件下,以薄层树脂相吸光光度法测定硅的新方法,本法灵敏度高(810=7.3×105L/molcm),比水相光度法提高16倍。精密度理想 (测定6.0g Si 6次,RSD=1.2%)。测定了高纯稀土中硅,线性范围0g/25ml~16g/25ml,检出限1.2g/L,回收率96%~101%。     

N263萃淋树脂的合成及其在金矿液分析中的应用

合成了N_(263)萃淋树脂,并测定了该树脂的一些性能。用合成的N_(263)树脂分离、富集矿石中的金,在5％～20％王水介质中均可定量吸附。上柱流速2ml·min~(-1),以2.0％硫脲-1.0mol·L~(-1)盐酸作洗脱液,洗脱液流速0.5ml·L~(-1),用过氧化氢破坏硫脲后,硫代米蚩酮光度法测定金。金在10～200μg范围能定量回收,回收率达98％。方法选择性好,树脂可重复使用15次以上。     

催化动力学光度法测定痕量钴

研究了以镁试剂Ⅰ作指示物,Co(Ⅱ)催化过氧化氢氧化镁试剂Ⅰ褪色反应的动力学条件,据此提出催化光度法测定痕量钴的新方法.方法的灵敏度为 1.15×10~(-11)g·ml~(-1),测定范围0.06～0.25μg/25ml,用于酒类中钴含量的测定,结果良好.     

钴(Ⅱ)-茜素红-罗丹明B-聚乙烯醇体系光度法测定痕量钴

提出了钴 (Ⅱ ) 茜素红 罗丹明B 聚乙烯醇体系光度法测定钴 (Ⅱ )的新方法。该方法灵敏度高 ,ε =3.2 8× 10 5L·mol- 1·cm- 1,线性范围为 0～ 7.5 μg/ 5 0ml,测定 2 μg钴 (Ⅱ ) 6次 ,RSD为2 .6 6 % ,用于水中痕量钴的测定 ,结果满意     

磷钼蓝体系薄层树脂相吸光光度法测定痕量钼的研究

提出了在酸性条件下,以磷钼蓝反应为基础的薄层树脂相吸光光度法测定钼。此方法灵敏度较高(ε705=8.1×104L·mol-1·cm-1),比液相光度法提高10倍,精密度理想(钼浓度为20μg/25ml,n=6),RSD为2.8%。应用此法测定天然水中钼,线性范围为0～18μg·ml-1,回收率为97%～102%。     

超高灵敏显色剂meso-四(4-氯苯基)卟啉与钴反应的分光光度法研究

本文研究了新显色剂meso-四(4-氯苯基)卟啉与钴的反应条件。在表面活性剂存在下,90℃恒温加热15min,试剂与钴形成稳定的1:1配合物。λ_(max)=420nm,ε_(420)=7.94×10~5L·mol~(-1)·cm~(-1),0～3.2μgCo/25ml符合比尔定律,为目前已报道的分光光度法测定钴最灵敏的方法。用来测定维生素B_(12)针剂中微量钴,结果满意。     

新试剂2-(5-硝基-2-吡啶偶氮)-5-二甲氨基苯甲酸分光光度法测定微量钴

本文报道用新试剂2-(5-硝基-2-吡啶偶氮)-5-二甲氨基苯甲酸分光光度法测定微量钴。配合物的表观摩尔吸光系数为1.31×10~5L·mol~(-1)·cm~(-1),Co∶5-NO_2-PAMB=1∶2,Co浓度在0～14μg/25mL范围内服从比耳定律。用于金属有机化合物中微量钴的测定,结果与理论值相符。     

镍(II)-丁二酮肟体系极谱催化波的机理研究

研究了镍(II)-丁二酮肟(DMG)体系极谱催化波的行为, 这一体系的极谱催化波可用于生物及岩矿中测定痕量镍和同时测定痕量镍、钴, 并对照研究了Co(II)-DMG体系和Ni(II)-DMG体系的机理.     

Extraction of manganese(II) with dithizone and potassium thiocyanate on foam sorbents for spectrophotometric determination in silicates

A method for selective extraction of Mn(II) with dithizone and potassium thiocyanate has been described. The method involves formation of a Mn(II)-thiocyanate-dithizone complex in a hexamine medium containing potassium thiocyanate (2.8M), dithizone (5.5-6.5 x 10(-5)M) and hydroxylamine hydrochloride (0.25%) at pH approximately 6 followed by extraction of the complex on polyurethane foam using batch squeezing mode within 1 hr. The sorbed Mn-thiocyanate-dithizone complex is eluted with acetone and made alkaline with 0.5 ml of a stabilizer solution (19 ml 2M NH(3) solution + 1 ml 5% hydroxylamine hydrochloride). The absorbance of the solution is measured at 506 nm. The adverse effect due to Pb may be obviated by separating the Pb as the sulphate during decomposition of sample and that due to iron may be removed before extraction of Mn by any suitable method. The other interfering elements (Cd, Zn, Ni, Co, Cu, etc.) are masked with KCN (6 x 10(-3)M optimum) solution. The method obeys Beer's Law from 0.1 to 2.0 mug Mn/ml. The method has been applied to various silicates, carbonates and glasses.     

Simple and rapid spectrophotometric determination of iron after preconcentration as its 1,10-phenanthroline complex on the natural polymer "chitin"

Preconcentration by collection of metal complexes on chitin has been applied to the spectrophotometric determination of iron in water. The iron is collected as its 1,10-phenanthroline (phen) complex on a column of chitin in the presence of tetraphenylborate as counter-ion. The iron(II)-phen complex retained on the chitin is eluted with an acetone-1M acetic acid mixture (8:2 v/v), and the absorbance of the eluate is measured at 512 nm. Beer's law is obeyed over the concentration range 1.1-11.2 mug of iron in 10 ml of eluate. In the presence of EDTA as masking agent, Ca, Mg, Al, Mn, Zn, Cd and Pb do not interfere in concentrations up to 100 times that of iron(II) and Co, Ni and Cu do not interfere in concentrations up to 20 times that of iron(II). Common inorganic anions do not interfere in concentrations up to 10,000 times that of iron(II). The proposed method has been applied to determination of iron in tap water.     

Determination of cadmium, zinc, nickel and cobalt in tobacco by reversed-phase high-performance liquid chromatography with 2-(8-quinolylazo)-4,5-diphenylimidazole as a chelating reagent.

A sensitive and selective method has been developed for the simultaneous determination of cadmium, zinc, nickel and cobalt. The method is based on the chelation of metal ions with 2-(8-quinolylazo)-4,5-diphenylimidazole (QAI) and the subsequent reversed-phase (RP) high-performance liquid chromatographic separation and spectrophotometric detection of the metal chelates. The chelates were separated on an RP column with acetonitrile-water containing ethylenediamine tetraacetic acid and sodium acetate (pH 7.5). Though Zn(II) and Cd(II) chelates with azo compounds were generally labile in the RP column, these chelates with QAI were successfully detected. When analyses were carried out at 575 nm and at 0.001 absorbance unit full scale, the peak height calibration curves were linear up to 2.0 ng for Cd(II), 2.4 ng for Zn(II), 0.14 ng for Ni(II) and 0.72 ng for Co(II) in 100-microL injections, respectively; the detection limits (3sigma, three times of the standard deviation for the blank signal) for Cd(II), Zn(II), Ni(II) and Co(II) were 4.8, 24, 2.4 and 7.2 pg in 100 microL of injected solution, respectively. The proposed method was successfully applied to the analysis of tobacco without any preliminary concentration or separation.     

Amberlite XAD-7 impregnated with Xylenol Orange: a chelating collector for preconcentration of Cd(II), Co(II), Cu(II), Ni(II), Zn(II) and Fe(III) ions prior to their determination by flame AAS

A new chelating resin, Xylenol Orange coated Amberlite XAD-7, was prepared and used for preconcentration of Cd(II), Co(II), Cu(II), Fe(III), Ni(II) and Zn(II) prior to their determination by flame atomic absorption spectrophotometry. The optimum pH values for quantitative sorption of Cd(II), Co(II), Cu(II), Fe(III), Ni(II) and Zn(II) are 4.5-5.0, 4.5, 4.0-5.0, 4.0, 5.0 and 5.0-7.0, respectively, and their desorptions by 2 mol L(-1) HCl are instantaneous. The sorption capacity of the resin has been found to be 2.0, 2.6, 1.6, 1.6, 2.6 and 1.8 mg g(-1) of resin for Cd, Co, Cu, Fe, Ni and Zn, respectively. The tolerance limits of electrolytes, NaCl, NaF, NaI, NaNO3, Na2SO4 and of cations, Mg2+ and Ca2+ in the sorption of the six metal ions are reported. The preconcentration factor was between 50 and 200. The t1/2 values for sorption are found to be 5.3, 2.9, 3.2, 3.3, 2.5 and 2.6 min for the six metals, respectively. The recoveries are between 96.0 and 100.0% for the different metals at preconcentration limits between 10 to 40 ng mL(-1). The preconcentration method has been applied to determine the six metal ions in river water samples after destroying the organic matter (if present in very large amount) with concentrated nitric acid (RSD < or = 8%, except for Cd for which it is upto 12.6%) and cobalt content of vitamin tablets with RSD of approximately 3.0%.     

Synthesis and characterization of mixed ligand complexes of copper(II), nickel(II), cobalt(II) and zinc(II) with glycine and uracil or 2-thiouracil

Mixed ligand complexes of Cu(II), Ni(II), Co(II) and Zn(II) formed with glycine and uracil or 2-thiouracil have been synthesized and characterized by elemental analysis, conductance, spectral (IR and electronic spectra) and magnetochemical measurements. Results show that glycine is bidentate in all cases; uracil behaves as a bidentate ligand in Cu(II) complex, coordinating through its one carbonyl oxygen and nitrogen, whereas in other cases it is only monodentate, coordinating only through nitrogen. With thiouracil, coordination occurs from carbonyl oxygen and one nitrogen in Cu(II) and Ni(II) complexes, but in the Co(II) complex coordination occurs from thionyl sulphur and nitrogen. In the Zn(II) complex it shows tridentate behaviour, coordinating through oxygen, sulphur and one nitrogen. Mixed Cu(II), Co(II) and Zn(II) complexes of uracil and of Ni(II) and Zn(II) with thiouracil are octahedral, whereas the mixed Ni(II) complex with uracil shows distorted tetrahedral geometry, and the mixed Co(II)-thiouracil complex is square planar. The mixed Cu(II)-thiouracil complex has a binuclear structure, with square planar arrangement around each copper atom.     

Detection and spectrophotometric determination of EDTA with cobalt(II) and phosphomolybdic acid in urine and detergents

A simple, rapid, sensitive and selective method for the microgram detection and spectrophotometric determination of EDTA in water, human urine and detergents, based on its reaction with Co(II) and phosphomolybdic acid at pH 0.5–2.0 is reported. Absorbance is measured against Co(II)–phosphomolybdic acid reference solution at 750 nm. The effect of time, temperature, pH and Co(II) or phosphomolybdic acid concentration is studied, and optimum operating conditions are established. Beer's law is applicable in the concentration range 0.3–1.9 μg ml⁻¹ of 10⁻⁵M EDTA. Its detection limit is 0.14 μg in the solution phase and 0.03 μg in the resin phase. The relative standard deviation is ±0.13 μg. Ag(I), Zn(II), Cu(II), Ni(II), Pb(II), Cd(II), Ca(II), Mg(II), Fe(III), Cr(III), U(VI), chloride, nitrite, phosphate, oxalate, borate and amino acids do not interfere.     

H-point standard addition method for simultaneous determination of cobalt(II) and zinc(II) ions

The H-point standard addition method (HPSAM) was applied to the simultaneous determination of zinc(II) and cobalt(II). This method is based on the difference in the absorbance of methylthymol blue complexes of Zn(II) and Co(II) at pH 6 using different wavelength pairs. The results showed that Zn(II) and Co(II) can be determined simultaneously with concentration ratios of 20:1 and 1:7.5. Under working conditions, the proposed method was successfully applied to the simultaneous determination of zinc and cobalt in synthetic, drinking water and vitamin samples.     

STUDY ON THE DETERMINATION OF TRACE BISMUTH(Ⅲ) BY THIN-LAYER RESIN PHASE SPECTROPHOTOMETRY

In this paper, a new thin-layer ion-exchange resin phase analytical method is introduced. It is based on that, the bismuthous cation can associate with iodic anions, so as to formed an anioncomplex [BiI-4] in a strong acidic environments. This anion complex can also exchanges with a weaker anions on the surface active site of anion exchange resin, so that a [R+] [BiI-4] solid phase binary associational system is produced. Owing to the solid system is a great many dispersive particulates, it can be pressed to a thin-layer by press tools of the so called "thin-layer resin phase"or "resin phase ", and using this solid association system spectrophotometry for the determination of trace metals. So it can increase the analytical sensitivity. This association system exhibits maximum absorbance at 460nm, and obeys Beer's law over the concentration range 0. 01ug/ml～1.20ug/ml of bismuthous(Ⅲ). It has a molar absorptivity of 7.1 ×105 [L/mol cm]. It indicated the resin phase spectrophotometry is a sensitive analytical method for trace bismuthous. It is 18 times higher than routine aqueous spectrophotometry. The relative standard deviations is 1.82% (n=6) for the measurements of 0. 5ug/ml Bi(Ⅲ). The detection limit of Bismuthous(Ⅲ) is 1.4 ×10-8mol/L. The method has applied to the analysis Bi(Ⅲ) in environmental water samples.     

Synthesis, characterization and applications of pyrocatechol modified amberlite XAD-2 resin for preconcentration and determination of metal ions in water samples by flame atomic absorption spectrometry (FAAS)

A new chelating resin is prepared by coupling Amberlite XAD-2 with pyrocatechol through an azo spacer, characterized (by elemental analysis, IR and TGA) and studied for preconcentrating Cd(II), Co(II), Cu(II), Fe(III), Ni(II) and Zn(II) using flame atomic absorption spectrometry (FAAS) for metal monitoring. The sorption is quantitative in the pH range 3.0-6.5, whereas quantitative desorption occurs instantaneously with 2 M HCl or HNO(3) The sorption capacity has been found to be in the range 0.023-0.092 mmol g(-1) of resin. The loading half time (t(1/2)) is 1.4, 4.8, 1.6, 3.2, 2.3 and 1.8 min, respectively for Cd, Co, Cu, Fe, Ni and Zn. The tolerance limits of electrolytes NaCl, NaBr, NaNO(3), Na(2)SO(4) and Na(3)PO(4) in the sorption of all the six metal ions (0.2 mug ml(-1)) are reported. The Mg(II) and Ca(II) are tolerable with each of them (0.2 mug ml(-1)) up to a concentration level of 0.01-1.0 M. The enrichment factor has been found to be 200 except for Fe and Cu for which the values are 80 and 100, respectively. The lowest concentration of metal ion for quantitative recovery is 5, 10, 20, 25, 10 and 10 mug l(-1) for Cd, Co, Cu, Fe, Ni and Zn, respectively. The simultaneous determination of all these metal ions is possible and the method has been applied to determine all the six metal ions in tap and river water samples (RSD相似文献