紫外吸光光度法测定碘离子

利用溴水氧化I- 形成IO- 3 ,过量溴水用甲酸除去后在过量碘化物存在下 ,IO- 3 氧化I-产生 3倍摩尔量I- 3 ,而I- 3 在紫外光区的 2 86nm具有最大吸收 ,并在 34 5nm处另有一略低的吸收峰 ,ε2 86=1.3× 10 5L·mol- 1·cm- 1,ε34 5=8.1× 10 4 L·mol- 1·cm- 1,均具有很高的灵敏度。I- 在 0～16μg/2 5ml范围内遵守比耳定律 ,方法有较好的选择性 ,方法简便快速 ,用于碘盐中碘离子的测定 ,结果满意     

溶剂浮选缔合物光度法测定痕量硒

根据亚硒酸 ( H2 Se O3)氧化 I-生成 I2 ,I2 与 I-配阴离子 ,I-3 ,配阴离子I-3 与孔雀绿阳离子 ( MG+ )发生离子缔合反应 ,用 N2 气将此缔合物浮选的三元缔合物用光度法测定硒。方法的 ε为 2 .2× 1 0 6L· mol-1· cm-1,RSD为2 .7% ,检出限为 4.7× 1 0 -10 g· m L-1     

痕量碘离子的铬(Ⅵ)-碱性呫吨染料体系分光光度法测定

在过量溴化物存在下的稀磷酸介质中 ,I-被Cr(Ⅵ )氧化成I2 后与Br-结合形成[I2Br] -配阴离子 ,该配阴离子能进一步与罗丹明6G、罗丹明B、吖啶红等碱性吨染料阳离子形成离子缔合配合物。在聚乙烯醇存在下 ,缔合物体系稳定且溶液颜色有明显的变化 ,可用于I-离子的光度测定。方法具有高灵敏度 ,不同体系的摩尔吸光系数在4 .96×104 ～1 .1×105 L·mol-1·cm-1 之间 ,以罗丹明6G和罗丹明B体系灵敏度较高。碘离子质量浓度分别在0～0.8mg/L(罗丹明B和罗丹明6G体系)、0～1.0mg/L(吖啶红体系 )之间遵守比尔定律。方法具有良好的选择性 ,用于海带、黄豆和含碘药片的测定结果令人满意     

负催化动力学光度法测定微量碘的研究

本文报道碘 ( I- )对重铬酸钾氧化罗丹明 B( RHB)褪色反应的负催化作用及其动力学分析 ,建立了测定微量碘的新方法 ,检出限 2× 1 0 - 8g/m L,线性范围 0～ 1 6μg/m L,表观摩尔吸光系数 6.7× 1 0 4 L·mol- 1· cm。方法用于海带、食盐等食品中微量碘的测定 ,结果满意     

流动注射安培法快速测定食盐中碘

报道了在酸性溶液中 ,IO- 3可被过量的I- 还原 ,FI流动注射安培法快速测定食盐中碘的方法。溶解于蒸馏水中的食盐样品 (30 μl)注入pH 1的 0 .1mol·L- 1NaCl + 1× 10 - 3mol·L- 1KI的载液中。自行研制的壁喷玻碳电极安培流通检测池作为工作电极 ,电位为 + 0 .2V(vs.SCE)。该系统和反向 (注入KI)系统的线性范围均为 1× 10 - 6 ～ 1× 10 - 4mol·L- 1,检出限为 5× 10 - 7mol·L- 1,相对标准偏差为 0 .8% (n =37) ,样品测定的回收率为 97.6 %～ 10 4 % ,采样频率 90样·h- 1。通过Bernoull恒流瓶可获得无脉冲载流。     

2,4-二羟基苯甲醛缩硫脲合汞(Ⅱ)为中性载体的高选择性碘离子电极的研究

报道了基于2,4-二羟基苯甲醛缩硫脲合汞(Ⅱ)为载体的溶剂聚合膜阴离子敏感电极,该电极对碘离子(I-)具有高的电位选择性和灵敏度,且呈现反Hofmeister选择性行为,其选择性序列为I-＞Sal-＞SCN-＞ClO-4＞Br-＞NO-2＞NO-3＞SO2- 3-＞Cl-＞So2- 4.该电极电位对碘离子呈近能斯特响应,其线性范围为2.0×10-6～1.0×10-1mol/L,斜率为-68.6 mv/dec,检出限为6.0×10-7 mol/L.将电极用于加碘盐中碘含量的测定,结果令人满意.     

氯化钠增敏光度法测定微量碘

1　引　　言碘是人体必需元素 ,对大脑的发育起着决定性的作用。碘的测定方法很多 ,我们在对经典的碘 淀粉显色反应研究时 ,观察到ＮａＣｌ能显著地提高显色灵敏度 ,并使可见光区的最大吸收波长明显蓝移的现象。在高浓度氯化钠溶液中 ,碘 淀粉溶液的最大吸收波长λｍａｘ=4 83ｎｍ ,较无ＮａＣｌ时蓝移 72ｎｍ ,最大摩尔吸光系数εｍａｘ=2 .7× 10 5Ｌ·ｍｏｌ- 1 ·ｃｍ- 1 ,灵敏度提高 5倍。碘含量在 0～ 1.6ｍｇ Ｌ内符合比耳定律 ;检出限为 0 .0 12ｍｇ Ｌ ;ＲＳＤ为 0 .3%。拟定了在高浓度ＮａＣｌ体系中测定碘的新方法 ,该法用于食…     

7-碘-8-羟基喹啉-5-磺酸与钒显色反应的研究及应用

在 0 .2 0mol·L- 1硫酸介质中 ,用过氧化氢作增敏剂 ,7 碘 8 羟基喹啉 5 磺酸 (Ferron)与钒 (Ⅴ )形成 1∶1的有色配合物 ,在 4 10nm处有最大吸收 ,其表观稳定常数为 4 .5× 10 3 ,摩尔吸光系数ε4 10 为 1.91× 10 3 L·mol- 1·cm- 1,钒浓度在 0 .10～ 2 0 .0 μg·ml- 1范围内符合比耳定律。该方法用于矿样中钒的测定 ,结果满意     

酸性络蓝K褪色光度法测定食盐中微量碘

在硫酸介质中 ,碘酸根对酸性络蓝 K具有褪色作用 ,且褪色的程度与碘酸根存在量有关 ,从而建立了光度法测定碘的新方法。方法最大吸收波长为 52 4 nm,表观摩尔吸光系数为 2 .1 9×1 0 4 L·mol-1·cm-1,碘的浓度在 0～ 60 μg/2 5ml范围内符合比耳定律。方法简单、快速、准确、选择性好、灵敏度高 ,用于测定碘食盐中的碘含量 ,结果满意     

二甲基黄褪色光度法测定微量碘

在硫酸介质中,溴化钾催化下,碘酸根对二甲基黄有褪色作用,且褪色的程度与碘酸根的量有关,从而建立了光度法测定碘的新方法。方法的最大吸收波长为515nm,表观摩尔吸光系数为3.1×104L·mol-1·cm-1,碘浓度在0～20μg/10ml范围内符合比耳定律,检出限为1.02×10-8g·ml-1。方法简单、快速、选择性好、灵敏度高,用于测定碘盐中碘的含量,结果满意。     

Hydrothermal synthesis of a chiral rare earth iodate (Gd(IO3)3 · H2O) showing the rare (3, 8)-connected (43)(4 · 62) (49 · 617 · 82) topology

In the presence of Cu(II) ions, a chiral rare earth iodate Gd(IO₃)₃?·?H₂O (crystallizing in P2₁ (no. 4) space group), was synthesized hydrothermally from Gd₂O₃ and HIO₃; the structure is the topologically (3,?8)-connected (4³)(4?·?6²)(4⁹?·?6¹⁷?·?8²) network, constructed from 3-connected trigonal nodes (I1, I3) and 8-connected tetragonal prism nodes (Gd1).     

PHOTOCHEMISTRY OF HALOGEN PYRIMIDINES: IODINE RELEASE STUDIES

The feasibility of using direct iodide (I-) measurements to monitor the photochemistry of the halogenated pyrimidines 5-iodocytosine and 5-iodouracil and their corresponding deoxynucleosides was examined. Radiation from either a germicidal lamp (lambda = 254 nm) or a sunlamp (lambda greater than 290 nm) was employed to induce homolytic splitting of the carbon-iodine bond and the release of iodine atoms. These atoms combine to form I2 which reacts with water to ultimately form I- and iodate (IO3-). The formation of I- was followed using either high performance liquid chromatography with electrochemical detection or a specific ion electrode. IO3- was assayed spectroscopically following its conversion to triiodide. The yields of I- relative to starting material destroyed were either close to the theoretical limit of 83% or higher depending upon (a) the compound being irradiated, (b) the irradiation wavelength and (c) the extent of exposure. Yields of iodide greater than 83% are generally accounted for by a concomitant reduction in the yield of iodate such that the sum I(-) + IO3- is approx. 100%. Because iodate is photochemically reduced to iodide by 254 nm but not sunlamp irradiation, exhaustive irradiation at 254 nm converts all of the iodate present to iodide. These studies have application to the use of photochemical methods for quantitating the percent substitution of iodinated pyrimidines in DNA, and should be useful in following the photochemistry of IdUrd and IdCyd substituted DNA.     

芳杂环二腈及其聚合物——Ⅸ.4,4’-联苯二甲腈聚合动力学

本文研究了4,4′-联苯二甲腈在4,4′-联苯二甲腈氯化锌配合物催化下的聚合反应动力学,氰基浓度通过以铁氰化钾为内标的石腊糊法的红外光谱定量分析法测定。结果表明:该聚合反应是二级反应,聚合反应速度和氰基浓度及配合物浓度各成一次方比例。聚合反应表观活化能为12.4千卡/克分子。此外,也研究了不同的4,4′-联苯二甲腈金属氯化物配合物为催化剂对4,4′-联苯二甲腈聚合反应速度的影响,并对聚合反应机理进行了讨论。     

Direktthermometrische bestimmung von thorium und lanthan in gläsern

A rapid method is described for the determination of thorium and lanthanum in non-silicate glasses. It is suitable for routine use in a works laboratory. The samples are dissolved in nitric acid. The thorium content is calculated from the measured heat of precipitation of thorium iodate, and the lanthanum content by difference from the heat of precipitation of both thorium and lanthanum oxalates together. The apparatus is calibrated by using standard solutions of the two metal ions. The standard deviations for the middle of the range (around 250 mg of the oxides) were 3·1 mg for ThO₂ and 1·7 mg for La₂O₃. An analysis takes about 1·5 hr.     

Kinetic study and analytical application of the iodate-hypophosphite reaction in strongly acidic solutions

The iodate—hypophosphite reaction in strongly acidic solutions was studied spectrophotometrically. Reaction rate constants and the activation energy of the reaction are reported. A method for determining hypophosphite on the basis of this reaction is described. Hypophosphite in the range 0.06–4 mg (10^-3–6·10^-2 M) can be determined with a relative error and relative standard deviation of 2—3%.     

1,3-Cyclopentanedione bis(4-methylthiosemicarbazone) monohydrochloride as a spectrophotometric reagent for the determination of lodate in acetic and perchloric acid media

1,3-Cyclopentanedione bis(4-methylthiosemicarbazone) monohydrochloride produces colored solutions with iodate ions in acid medium. The yellow color obtained has been used to proposed Spectrophotometric methods for determination of IO₃^? in the concentration range 1.0–11.0 ppm in acetic acid medium (molar absorptivity 1.08 × 10⁴ liters mol^?1 cm^?1 at a wavelength of 415 nm) and 0.5–8.0 ppm in perchloric acid medium (molar absorptivity 2.05 × 10⁴ liters mol^?1 cm^?1 at a wavelength of 400 nm).     

Crystal Structure of a Cadmium Iodate Monohydrate: Cd(IO3)2·H2O

Single crystals of Cd(IO₃)₂·H₂O are obtained by slow evaporation of aqueous solutions of CdCl₂ and KIO₃. This compound crystallizes in the triclinic space group P1¯ [a = 7.119(2), b = 7.952(2), c = 6.646(2)Å, α = 102.17(2)°, β = 114.13(2)°, γ = 66.78(4)°]. The structure consists in Cd — (μ2‐O)₂ — Cd dimers with a metal — metal distance of 3.74Å. These dimers are connected through two iodate bridges resulting in layers parallel to the (010) plane. The 3D linkage is ensured by I1 — O1 long bonds (2.775Å).     

Synthesis and characterization of f-element iodate architectures with variable dimensionality, alpha- and beta-Am(IO3)3

Two americium(III) iodates, beta-Am(IO3)3 (I) and alpha-Am(IO3)3 (II), have been prepared from the aqueous reactions of Am(III) with KIO(4) at 180 degrees C and have been characterized by single-crystal X-ray diffraction, diffuse reflectance, and Raman spectroscopy. The alpha-form is consistent with the known structure type I of anhydrous lanthanide iodates. It consists of a three-dimensional network of pyramidal iodate groups bridging [AmO8] polyhedra where each of the americium ions are coordinated to eight iodate ligands. The beta-form reveals a novel architecture that is unknown within the f-element iodate series. beta-Am(IO3)3 exhibits a two-dimensional layered structure with nine-coordinate Am(III) atoms. Three crystallographically unique pyramidal iodate anions link the Am atoms into corrugated sheets that interact with one another through intermolecular IO3-...IO3- interactions forming dimeric I2O10 units. One of these anions utilizes all three O atoms to simultaneously bridge three Am atoms. The other two iodate ligands bridge only two Am atoms and have one terminal O atom. In contrast to alpha-Am(IO3)3, where the [IO3] ligands are solely corner-sharing with [AmO8] polyhedra, a complex arrangement of corner- and edge-sharing mu2- and mu3-[IO3] pyramids can be found in beta-Am(IO3)3. Crystallographic data: I, monoclinic, space group P2(1)/n, a = 8.871(3) A, b = 5.933(2) A, c = 15.315(4) A, beta = 96.948(4) degrees , V = 800.1(4) A(3), Z = 4; II, monoclinic, space group P2(1)/c, a = 7.243(2) A, b = 8.538(3) A, c = 13.513(5) A, beta = 100.123(6) degrees , V = 822.7(5) A(3), Z = 4.     

Reverse flow injection spectrophotometric determination of iodate and iodide in table salt

A very simple and sensitive reverse flow injection method is described for the determination of iodate and iodide. The iodate reacts with excess iodide in acidic medium to form tri-iodide, which can be spectrophotometrically monitored at 351 nm, and the absorbance is directly related to the concentration of iodate in the sample. The determination of iodide is based on oxidizing iodide to iodate. The calibration curve is linear in the range of 0.02-3.0 μg ml⁻¹ I with r²=0.9998, and the limit of detection is 0.008 μg ml⁻¹ I. The chemical and flow injection variables were studied and optimized to make the procedure suitable for quantitating iodate and iodide in table salts. It is shown that the reverse flow injection analysis could greatly improve the sensitivity and precision for determination of iodate with a relative standard deviation of 0.9%. A complete analysis, including sampling and washing, could be performed in 35 s. The procedure was applied successfully to the determination of iodate and iodide in table salts, and the results were statistically compared with results determined by standard iodometry method.     

共振光散射法测定丁胺卡那霉素

研究了以达旦黄（TY）作为共振光散射探针测定市售药品中丁胺卡那霉素（AMK）的测定方法．该方法基于在pH=5．5的Britton—Robinson缓冲溶液中，达旦黄和丁胺卡那霉素结合后有强烈的共振光散射作用．在λ=482nm处，共振光散射强度（△IRLS）最大且光散射的强度与AMK的浓度在0．4～2．4mg·L^-1范围内成正比（相关系数r=0．9986），检出限为8．6×10^-3mg·L^-1．该方法简便、快速、灵敏，对1．0mg·L^-1的AMK溶液平行测定11次，RSD=2．57％．用于市售样品的分析测定，结果满意。