Spectrophotometry Determination of Cobalt after Extraction of its Ternary Complex with 3-(4-Phenyl-2-Pyridyl)-5,6-Diphenyl-1,2,4-Triazine and Tetraphenylborate into Molten Naphthalene

The reaction of 3-(4-phenyl-2-pyridyl)-5,6-diphenyl-1,2,4-triazine (PPDT) and tetraphenylborate (TPB) with cobalt (II) has been studied to determine the optimum conditions for the extraction and quantitative spectrophotometry determination of this metal. The ternary complex is extracted into molten naphthalene at pH 3.6–7.4. The solid naphthalene containing the cobalt associated complex is separated by filtration and dissolved in acetonitrile. Beer's law is obeyed in the concentration range 8–140 μg cobalt in 10 ml of acetonitrile solution. The molar absorptivity and sensitivity are 4.2×10³ l·mol^?1·cm^?1 and 0.01408 μg/cm², respectively. The other factors such as pH, amounts of reagents and naphthalene, shaking and standing times, and the effect of diverse ions are studied. The method has been applied to the determination of cobalt in iron steel alloys.     

牛血清白蛋白与甲基橙结合反应的研究

用分光光度法研究了牛血清白蛋白与甲基登在酸性溶液中的结合反应，认为两者通过非共价键结合，研究了溶液吸光 度与组分浓度的关系，对Ｓｃａｔｃｈａｒｄ模型用于自理蛋白质染色反应时存在的总是作了讨论，提出了表观结合常数的概念，推导了求算表观结合常数和最大结合数的线性回归公式。     

电荷转移络合物分光光度法测定磺胺脒的研究

研究了电子给体磺胺脒与电子受体对苯醌之间的荷移反应。结果表明 ,在乙醇介质中磺胺脒与对苯醌能形成橙红色电荷转移络合物 ,且反应体系的pH范围较宽。络合物的最大吸收波长λmax=497.6nm ,表观摩尔吸光系数为 2 .3 5× 1 0 3L·mol- 1 ·cm- 1 ,比耳定律的线性范围是 0～ 5 0mg/L ,络合比为 1∶2。应用拟定的方法测定磺胺脒制剂的含量 ,平均回收率为 1 0 0 .4% ,可用于磺胺脒制剂的分析。     

Determination of dissolved inorganic phosphorus in natural waters at nanomolar concentrations using a long capillary cell detector

A high sensitivity spectrophotometric system using a long capillary cell (LCC) detector was developed to determine dissolved inorganic phosphorus (DIP) at nanomolar concentrations in natural waters. The colorimetric chemistry used is based on the classical molybdophosphate blue technique. The radiation source is a near-infrared light-emitting diode and a silicon phototransistor is used as a detector. Method parameters were optimized for the final LCC design. With a 600-mm LCC, a detection limit (twice the standard deviation of the blank) of 1 nmol l^?1 was obtained with a relative standard deviation of 6%. The working range of the instrument is 1–500 nmol l^?1 DIP, and a sample volume of 10 ml is required for each analysis. The technique was applied to both fresh and marine water. The instrument is compact, relatively simple and easy to use in the laboratory and the field.     

Stereoselective adduct formation of α-acylcamphorato-copper(II) chelates with some chiral Lewis bases

The formation constants of the mono-adducts of α-acylcamphorato-copper(II) chelates such as (+)-Cu(facam)₂, (?)-Cu(facam)₂, (+)-Cu(hfbc)₂ and (?)-Cu(hfbc)₂ with some chiral Lewis bases were determined spectrophotometrically in benzene. In order to compare the adduct formation constants obtained with the (+)- and (?)-forms, some pairs of chiral Lewis bases such as 1-amino-2-propanol [(R)(?), (S)(+)], 1-(α-naphthyl)ethylamine [(R)(+), (S)(?)], α-phenyl ethylamine [(R)(+), (S)(?)] and also quinine and quinidine were examined as neutral ligands. Although not very pronounced, the effects of combinations obtained for (+)- or (?)-Cu(II) chelates and (+)- or (?)-ligands indicate that formation constants obtained by the formation of adducts with the ligands having different directions of the optical rotation seems to be superior to those with the same direction.     

溶剂浮选-间接光度法测定抗坏血酸

于pH 7.0的磷酸盐缓冲介质中,CTMAB＋及I3-离子间借静电引力形成离子缔合物,可将其浮选入5.0 mL苯中,此缔合物在溶剂中,于365 nm处有吸收峰,较简单的I3^-离子在相同条件下的吸收峰（350 nm）红移了15 nm。在此溶液体系中存在抗坏血酸时使离子缔合物产生褪色反应,且在抗坏血酸浓度在25μg/50 mL以内时与吸光度的降低值（ΔA）间呈线性关系。在抗坏血酸浓度为6.0μg/50 mL时连续测定6次,所得结果的RSD为1.2%,回收率在96%-101%之间。     

Spectrophotometric determination of lead in vegetables with dibromo-p-methyl-carboxysulfonazo

A new highly sensitive and selective chromogenic reagent dibromo-p-methyl-carboxysulfonazo (DBMCSA) was synthesized and studied for the spectrophotometric determination of lead in detail. In 0.25 M phosphoric acid medium, which greatly increases the selectivity, lead reacts with DBMCSA to form a 1:2 blue complex, having a sensitive absorption peak at 648 nm. Under the optimal conditions, Beer's law is obeyed over the range from 0 to 0.8 μg ml⁻¹ Pb(II) and the apparent molar absorptivity is 1.04×10⁵ l mol⁻¹ cm⁻¹. The detection limit and the variation coefficient were found to be 2.14 ng ml⁻¹ and 1.0%, respectively. It is found that, except for Ca(II) and Ba(II), all foreign ions studied do not interfere with determination. The interference caused by Ca(II) and Ba(II) can be easily eliminated by prior extraction with potassium iodide-methylisobutylketone. The method has been applied to the determination of lead in vegetables with satisfactory results.     

Spectrophotometric determination of total phenolics by solvent extraction and sorbent extraction optosensing using flow injection methodology

Flow injection analysis (FIA) procedures for the Spectrophotometric determination of phenol involving in-line concentration by solvent and sorbent extraction have been developed. The imine product formed in the reaction between phenol and 4-aminoantipyrine (4-AAP) is either extracted into chloroform (solvent extraction) or is temporarily retained on C₁₈-modified silica material contained in a microcolumn (sorbent extraction). In the latter case two variants of detection have been used namely the Spectrophotometric measurement of the methanolic eluent containing the concentrated dye and at-column optosensing of the retained reaction product followed by methanol elution to maintain reversibility of the process. In the solvent extraction procedure a 10-fold increase of sensitivity compared to the common FIA method without extraction is achieved but no corresponding improvement in detectability is observed. Under optimized conditions the detection limit amounts to 8 μg l⁻¹. Using sorbent extraction methodology, high concentration factors can be obtained when large sample volumes are used. The only limitation in getting correspondingly lower detection limits are an increasingly high and variable blank value with sampling volume. The detection limits obtained for measurement of the absorbance in the eluent and on-column optosensing are 11 μg l⁻¹ and 0.4 μg l⁻¹, respectively. A study of the extractability of various phenol derivates using both solvent and sorbent extraction revealed lower relative response rates compared to the FIA method without extraction. Phenolics that possess an additional acidic group are present in ionized form at the high pH of the assay and are not extractable at all.     

一阶导数吸光光度法测定碘酸钾碘盐中碘

采用一阶导数吸光光度法测定碘酸钾碘盐中碘 ,线性范围为 0～ 12 μg·ml-1,检出限为1.6μg·ml-1,对盐样进行重复测定 ,相对标准偏差≤ 1.9% ,对样品进行加标回收试验 ,回收率在 97.0 %～ 10 2 .5 % ,结果良好     

催化动力学光度法测定痕量锆

研究了在弱酸性介质中，锆（Ⅳ）催化过氧化氢氧化铬蓝黑Ｒ这一新的指示反应及其动力学条件，建立了一种高灵敏、高选择性测定痕量锆的新方法，方法检出限为３．７４×１０－１１ｇ／ｍＬ，线性范围０～１．１μｇ／２５ｍＬＺｒ（Ⅳ）．用于合金钢中痕量锆的测定，结果满意．