煌焦油蓝分光光度法测定微量亚硝酸根

本文研究了在盐酸介质中微量亚硝酸根与煌焦油蓝发生的重氮化反应,建立了测量微量亚硝酸根的新方法。方法的线性范围为０．５￣１２μｇＮＯ２＾－／２５ｍＬ,检出限为０．５μｇ ＮＯ２＾－／２５ｍＬ。方法已用于水中微量亚硝酸根的测定。并对机理进行了初步讨论。     

多波长线性回归分光光度法同时测定磷和硅

以钼酸铵－Ｓｂ＾３＋－抗坏血酸为显色体系,详细考察了磷、硅的锑钼蓝杂多酸络合物的最佳形式条件,据此建立了多波长线顺归分光光度法同时测定磷、硅的新方法。该方法操作简便、快速、对多种环境水样中痕量磷、硅测定的相对标准偏差小于５％。测定结果与利用光度法分别测定的结果相吻合,相对误差小于１０％。     

葛根素在酸碱溶液中的紫外光谱特性及应用

葛根素在酸碱溶液中具有不同的紫外吸收光谱特性。以葛根素碱溶液为测定液,以等浓度的葛根素水溶液为参比液,用差示法测定其吸光度。结果表明:在337 nm处,当葛根素浓度为1.0×10-5~1.0×10-4mol/L时,吸光度与浓度之间存在良好的线性关系,据此建立了测定葛根素的差示紫外光谱法。用此法直接测定了葛根和葛根素注射液中葛根素的含量,平均回收率分别为99.5%(RSD=1.66%)、99.7%(RSD=0.85%)。本法结果与高效液相色谱(HPLC)法对照,对同一样品进行对照测定,结果令人满意。     

顺序注射停流分光光度法测定痕量碘

食物中碘的含量一直是人们关注的问题,研究食物中微量碘的分析方法具有重要的现实意义.目前测定碘的方法主要有色谱法[1,2]、荧光法[3,4]、分光光度法[5,6]等.     

Spectrophotometric Study of the Effect of Cationic Micelles on the Reaction Between Gallein and Th(IV)

Abstract

The acid dissociation equilibria of gallein (pyrogallolphthalein, gall), as a xanthene dye, in the presence of various surfactants‐cationic, anionic, nonionic, are discussed. The coexistence of a cationic surfactant, such as hexadecyltrimethylammonium chloride (HTAC) slightly enhanced the acid dissociation, and led to a chromogenic reaction between metal ions and gall in weakly acidic media. The ternary complex between gall and Th(IV), in weakly acidic media and in the presence of N-hexadecylpyridinium chloride(HPC), was very stable with definitive spectra. However, the complex was easily decomposed in proportion to the concentration of citrate ion.

Therefore, simple and rapid spectrophotometric methods for the determination of Th(IV) and citrate ion were respectively established, by using the gall-Th(IV)-HPC ternary complex in the cationic surfactant micelle. Beer's law was obeyed over the range 0 to 90 μg of Th(IV) and 12 to 35μg of citrate ion, in a final volume of 10 ml. The Sandell sensitivities were estimated to be 0.0013μg/cm² Th(IV) and 0.0005μg/cm² citrate ion at 600 nm. The analytical procedures were simple and did not require any organic solvent extraction.     

Spectrophotometric Determination of δ4 -3-Ketosteroids Using Oxalyldihydrazide

Abstract

A novel spectrophotometric method for the assay of δ⁴ -3-Ketosteroids in formulations is presented. Oxalyldihydrazide in methanol reacts selectively with δ⁴-3-Ketosteroids at pH 2 forming stable hydrazones which exhibit intense absorption specta at 300 nm. and high molar absorpitivities ranging from 14480–18750 for most steroids studied. Methyltestosterone showed exception ally high sensitivity where its molar absorpitivity was 21630. As little as 5–30 μg steroid were determined with 99.28 ± 0.65–100.16 ± 0.94% accuracy. The method was applied successfully to the micro-determination of cortisone, hydrocortisone, hydrocortisone acetate, norethisterone, norethisterone acetate, norgestrel and methyltestosterone in substance as well as in different pharmaceutical dosage forms. The precision of assay was compareble with existing spectrometric methods for ketosteroid drugs. The method is simple, accurate mean - while selective and more sensitive than the INH-method.     

Electron-impact induced fluorescence for EUV spectrometer–detector calibration

EUV-Spectra of electron-impact induced fluorescence from rare gases were recorded for an impact energy of 3.5 keV intending their application in the first step for spectrometer wavelength scale calibrations. The spectra are in the investigated range of 165–314 nm in good agreement with previously measured and calculated spectra. Nearly all observed lines could be identified including 196 new lines. 183 lines mainly for krypton and xenon could not be identified. The spectra are presented and discussed. A compendium of 1670 lines and their identification is added as supplementary tables. The spectra show a number of strong lines which are well suited for spectrometer wavelength scale calibrations and once their intensity relation is deduced can be used for a sensitivity determination of a spectrometer–detector combination as described in the introductory and experimental sections of the paper.     

秦岭产荚果蕨中总甾酮含量的测定

研究了超声提取法提取3种荚果蕨属植物中总甾酮的最佳提取工艺。确定最优的提取工艺条件为:60%的乙醇,料液比1:40(g/mL),270W超声50min。比较了秦岭产荚果蕨属3种植物中总甾酮的含量,确定总甾酮含量最高的为荚果蕨,其次为中华荚果蕨和东方荚果蕨。对荚果蕨醇提物对DPPH自由基清除活性进行研究,结果显示其清除活性依次为根状茎>营养叶>BHT>孢子叶。     

Determination of Traces of Mercury (II) and Phenylmercury by Direct Polyurethane foam Thin-Layer Spectrophotometry

Abstract

The determination of mercury and phenylmercury in the ppb concentration range using polyurethane foam (PUF) thin-layer spectrophotometry has been described. Sorption of mercury and phenylmercury into foam parallepiped loaded with diphenylthiocarbazone (dithizone) contributed to considerable improvement in the absorbance value of the colored species, being concentrated about 140 times.

The method allowed the achievement of satisfactory results, the detection limits are 5 and 10 μg per litre for mercury and phenylmercury, respectively, for 100ml sample volume. The average recovery from tap water amounts to 100% for mercury and 96.6% for phenylmercury.     

Quick Cuvette Test for Thiol Compounds

ABSTRACT

Plastic cuvettes coated chemically with Prussian Blue films were investigated as quick disposable spectrophotometric test for mercapto-compounds. The determination is based on discoloration of the coating film due to its reduction by analyte. The changes of film absorbance were measured at 720 nm. It was found that the cuvettes can be used for selective determination of cysteamine, β-mercaptoethanol and L-cysteine in millimolar ranges of concentration. The test is useful for determination of L-cysteine and N-acetylcysteine in pharmaceutical products.