Spectrophotometric determination of scandium with bromopyrogallol red

A highly sensitive spectrophotometnc method for scandium with Bromopyrogallolo Red is described;) mierogram amounts of scandium can be determined by measurement 'at 610 mmu and pH 6-1. The molar-absorptivity is 2.4 x 10(4) at 610 mmu. Formation of a 1:1 complex of scandium with Bromopyrogallol Red is confirmed, Common cations interfere, but can be separated completely by three successive ioń-exchange (Steps, so the method can be applied to the determmation of traces of scandium in silicate rocks. Results are quoted for scandiumn in several types of igneous rocks.     

Spectrophotometric determination of palladium using arsenazo I

A new simple rapid method for the spectrophotometric determination of palladium using arsenazo I is given. The optimum conditions favoring the formation of the complex are extensively investigated; the molecular structure was found to be 1:1. Beer's law is obeyed for the ranges 1.0–10.6 or 0.64–6.39 ppm of Pd.     

Spectrophotometric determination of rare earth elements and thorium with arsenazo

The simultaneous spectrophotometric determination of rare earth elements (lanthanum and gadolinium) and thorium with arsenuzo is described. In 0.05 N nitric acid, thorium alone forms a colored complex with the reagent; at PH 7.2 both thorium and the rare carths form colored complexes. Satisfactory results were obtained with weight ratios of Th/rare earths ranging from 0.2 to 10.     

Spectrophotometric determination of microamounts of scandium with o-chlorophenylfluorone and cetyltrimethylammonium bromide

The reaction of scandium(III) with o-chlorophenylfluorone (o-CIPF) in the presence of cetyltrimethylammonium bromide (CTMAB) has been studied. In an acetate buffer at pH 4.4, a red-purple complex is obtained, with maximum absorption at 569 nm and a molar absorptivity of 1.31 x 10(5)1.mole(-1).cm(-1). The composition of the complex is found to be 1:2:2 Sc-o-CIPF-CTMAB. Beer's law is obeyed over the range 0-12 mug/25 ml scandium. The proposed method has been used for determination of trace scandium in tungsten ores after its prior separation by solvent extraction.     

Colorimetric uranium determination with arsenazo

A rapid and sensitive method is described for the quantitative colorimetric determination of uranium(Vl). Masking agents such as EDTA, tartaric acid or thioglycerol make possible the determination of uranium in the presence of many foreign metal ions. If thorium is present, a preliminary extraction of uranium as the diethyldithiocarbamate is required.     

Spectrophotometric determination of scandium with anthrarufin-2,6-disulfonic acid (disodium salt)

A new spectrophotometric method for the determination of scandium, is described using anthraru-fin-2, 6-disulfonic acid (disodium salt) as a reagent. The color reaction has a sensitivity of 0.004 μg Sc per cm² for log $\text{I}{}_0\text{1}$ = 0.001 and obeys Beer's law up to 2 p.p.m. The effects of ph, time, order of addition of the reagents, temperature, and diverse ions were investigated. A separation procedure was developed and applied to six salt solutions containing scandium plus a variety of foreign ions.     

阴离子树脂苯取富集-分光光度法测定煤矸石中痕量钪

研究了对乙酰基偶氮氯膦(CPApA)与钪(Ⅲ)的显色反应,在HNO3介质中,在Triton X-100存在下,CPApA与钪(Ⅲ)反应生成摩尔比为1:1的稳定配合物,该配合物可用717型阴离子树脂交换柱萃取富集,再通过树脂相光度法测定钪,由此建立了测定钪的新方法.吸附配合物树脂相的最大吸收波长为690 nm,表观摩尔吸光系数为9.56×105 L·mol-1·cm-1.钪的质量浓度在0～480μg/L范围内符合比耳定律.经阴离子树脂交换柱萃取富集后,钪的测定灵敏度可提高数倍,大多数常见离子不干扰测定.方法应用于煤矸石痕量钪的测定,结果满意.样品分析结果的相对标准偏差小于5%,加标回收率为96.0%～102.5%.     

Spectrophotometric study of the reactions of arsenazo III with alkaline-earth metals

Arsenazo III is used as a spectrophotometric reagent for alkaline-earth metals. The molar absorptivities of the calcium, strontium and barium complexes at 650 nm are 4.40 x 10(4), 4.00 x 10(4) and 3.65 x 10(4) l.mole(-1).cm(-1) respectively. The interference of magnesium is eliminated at pH 5-6. The use of sodium sulphate as masking agent permits the determination of small amounts of calcium, strontium and magnesium in the presence of barium. The alkaline-earth ions can be determined in the presence of each other at pH 4.2 at the 2-10 mug level. Some organic solvents such as dioxan, acetone and ethanol increase the sensitivity and selectivity in acidic medium. The stability constants have been measured and the structure of the complexes is discussed.     

Extractive photometric determination of thorium with arsenazo DAL

Arsenazo DAL, the dianilide of3,6-bis (2'-arsonophenylazo)-4,5-dihydroxy-2,7-naphthalenedisulphonic acid, is proposed as an extractive photometric reagent for the highly selective determination of trace amounts of thorium.     

Spectrophotometric determination of zirconium, uranium, thorium and rare earths with arsenazo III after extractions with thenoyltrifluoroacetone and tri-n-octylamine

A method is described for the spectrophotometric determination of microgram amounts of zirconium, uranium(VI), thorium and rare earths with Arsenazo III after systematic separation by extraction. First zirconium is extracted into a xylene solution of thenoyltrifluoroacetone (TTA) from about 4M hydrochloric acid. Uranium(VI) is then extracted into a xylene solution of tri-n-octy lamine from about 4M hydrochloric acid. Thorium is next extracted into TTA solution at pH about 1.5, and finally rare earths are extracted into TTA solution at pH about 4.7. Each metal is back-extracted from the organic phase before determination.     

Spectrophotometric determination of thorium with arsenazo III in the organic phase after extraction with di-(2-ethylhexyl)orthophosphoric acid

A simple, direct colorimetric determination of thorium extracted from chloride solution with di-(2-ethylhexyl)orthophosphoric acid is described; the colour is developed in the organic phase by adding arsenazo III and then isopropanol. Two different procedures are outlined for different thorium levels; maximum absorbance occurs at 660 nm and Beer's law is obeyed within limited ranges. Molar extinction coefficients for the two methods are 4.93 · 10⁴ and 8.77 · 10⁴ respectively. With the more sensitive method, 0.696 μg Th/ml was determined with 0.0028 as standard deviation. The effects of the various parameters were studied. Among 69 foreign cations tested, serious interferences are U(VI), Se (IV), Ti(IV), Y and the rare earths. Of the common anions, only large amounts of sulpliate slightly interfered. Several ways of overcoming interferences are suggested, with particular-reference to uranium.Several extensions of the method are outlined; 2 p.p.b. Th in aqueous media can be determined by modifying the extraction step. The procedure also appears to be extremely sensitive for the light rare-earth elements.     

Triton X-100增敏光度法测定铝土矿中的微量钪

研究了在HCl溶液中微量钪(Ⅲ)-偶氮氯膦Ⅲ(CPAⅢ)之间的配合反应。结果表明,在0.5mol/LHCl溶液中和TritonX 100的存在下,有色溶液的最大吸收波长为680nm,表观摩尔吸光系数为2.62×104L·mol-1·cm-1。钪(Ⅲ)质量浓度在0～0.45mg/L范围内符合比耳定律,钪(Ⅲ)的加标回收率在98.0%～105.1%之间,RSD(n=6)为2.1%～2.6%。可用于铝土矿中的微量钪的测定。     

Spectrophotometric determination of scandium based on the cocoloration effect in scandium-cerium-p-acetylchlorophosphonazo (CPApA) system

Scandium in the presence of cerium(III) forms, with p-acetylchlorophosphonazo (CPApA), a heteropolynuclei ternary β-complex of scandium-cerium-CPApA. The complex gives a very sensitive reaction for scandium with a molar absorptivity of _Sc = 2.29 × 10⁵ l mol⁻¹ cm⁻¹ due to the cocoloration effect. Most foreign ions can be tolerated in considerable amounts. The optimum conditions and the mechanism of the complex formation reaction are discussed. A simple method is proposed for the determination of scandium in alloys, with satisfactory results.     

Spectrophotometric determination of La, Ce, Pr and Nd in the presence of copper by use of arsenazo III

Summary Arsenazo III was applied to the determination of the total amount of La, Ce, Pr and Nd in the presence of Cu, using sodium thiosulphate for masking Cu up to 50 mg. The lanthanides can be analyzed within the range of 0–2.4 or in presence of Pb, Al, Ni, Fe 0–1.6 mg/l. Interferences of Zn, Mn, Ni, Al, Sn, Pb and Fe were examined. The procedure was applied to the determination of Ce in CuSnCe alloys and Al and Pb brasses without prior separation of the matrix.     

Spectrophotometric determination of molybdenum with phenylfluorone

Spectrophotometric studies on the reaction between molybdenum as molybdate (MoO₄^2?) and phenylfluorone are presented. The reaction conditions are optimized to develop an intense color (molar absorptivity is 3.8 × 10³) selective and sensitive for the Spectrophotometric determination of molybdenum. The absorbance is measured at 560 nm, at a pH of 1.5–3. The colored complex is stable for up to 24 hr, Beer's law is obeyed, over the concentration range of 1 to 4 μg/25 ml. The relative standard deviation is 2% and the sensitivity of the method is 1.60 × 10^?4 mg/ml.     

Spectrophotometric determination of hexafluoroarsenate with ferroin

A spectrophotometric method for the hexafluoroarsenate anion is described. The determination involves selective extraction of the tris(1,10-phenanthroline)iron(II) salt of the anion into n-butyronitrile, followed by measurement of the absorbance of the organic layer. The extracts give good Beer's law plots over a wide range of concentrations and more than 98% of the hexafluoroarsenate is removed in a single extraction. Interference studies were made on a number of anions.     

Spectrophotometric determination of selenium with dithizone

Microgram amounts of selenium(IV) are determined by measuring the decrease in absorbance of dithizone in carbon tetrachloride solution at 620 nm. Relative standard deviations for samples containing 0.20 and 1.00 μg of selenium(IV) are 0.6% and 0.4%, respectively. Of several metals tested only copper (at the 1.0-μg level) and iron (at the 100-μg level) interfere but high concentrations of nitric or perchloric acid cause low results. A reinvestigation of the reaction of selenium(IV) with dithizone suggests a formula Se(HDz)₄ for the dithizonate.