Dipali Kundu

Spectrophotometric determination of platinum in glass after extraction with polyurethane foam

A spectrophotometric method has been developed for determination of trace amounts of platinum in glass. The method is based on the extraction of platinum(II) from 1M hydrochloric acid containing 0.2M stannous chloride and 4 x 10(-4)M dithizone onto polyurethane foam, elution with acetone (containing 3% v/v concentrated hydrochloric acid) and measurement of the absorbance of the eluate at 530 nm. Beers law is obeyed up to 10.0 microg/ml Pt. The minimum platinum level in the eluate that can be determined by this method is 0.1 microg/ml.

Release of Zinc and Phosphate Ions from ZnO-P2O5Glass Systems and its Characterization

Release of zinc and phosphate ions from glasses has been studied in aqueous medium (pH—5.7, 6.5 and 8.0). Zinc phosphate glasses of five different compositions corresponding to ZnO: P2O5 molar rati...

Evaluation of measurement uncertainty components associated with the results of complexometric determination of calcium in ceramic raw materials using EDTA

Calcium is an important constituent of mineral like calcite, dolomite, gypsum and bio-ceramic raw material like hydroxyapatite. Those are frequently used for the manufacture of cement, mortar, glass, synthetic ceramic bone supplement, dental enamel, etc. Determination of exact quantity of calcium in those materials is therefore very essential. The calcium content has been determined complexometrically in a ceramic raw material at pH 12, using di-sodium salt of EDTA. The major sources of uncertainty of the results of measurement are contributions from repeatability, standardization of EDTA, volume measurement by volumetric flask, burette, pipette and end point detection. Sources of uncertainty have been identified and combined by following the EURACHEM guidelines. The results show that the major sources of uncertainty arise from standardization, repeatability of the experiment and end point detection by burette. Cause–effect diagram has been drawn to explain the uncertainty budget.

Spectrophotometric Determination of Silver in Glass and Ceramic Materials by Foam Extraction

Abstract A simple spectrophotometric method has been developed for determination of silver in special glasses. The method involves decomposition of glass with hydrofluoric acid and nitric acid, formation of primary Ag(I)-dithizonate in 0.05 M nitric acid and 1 × 10−5 M dithizone, extraction of silver dithizonate on polyurethane foam, elution with acetone and measurement of absorbance at 500 nm of the colour formed by its secondary complex in ammoniacal acetone medium. The method obeys Beers law from 0.1 μg Ag/ml to 6.0 μg Ag/ml. The molar absorptivity has been found to be 3.45 × 104l mole−1 cm−1 at 500 nm.

Determination of Trace Impurities in Silica Sand by Inductively Coupled Plasma Atomic Emission Spectrometry

Determination of trace impurities in silica sand is simplified by the introduction of automated inductively coupled plasma atomic emission spectrometer (ICP AES). Due to high sensitivity and wide linear concentration range most of the elements are possible to be determined directly using ICP AES in one sample solution. The instrument has been optimized using silica sand matrix considering radio frequency (RF) power, nebulizer pressure, auxiliary flow rate and pump speed. A multielement programme for trace impurity analysis of silica sand has been developed. The accuracy of overall analysis was first estimated by the analysis of three certified reference materials, and good agreement between measured and reference values has been found for all the elements. As the second way of determining accuracy, results obtained from independent analytical techniques ICP AES and AAS have been compared by analyzing real samples.

Spectrophotometric Determination of Silica in Barium Titanate and Zirconia Ceramics after Extraction of Silicomolybdate on Polyurethane Foam

A spectrophotometric method has been developed for the determination of trace amounts of silica in barium titanate and zirconia ceramics based on the formation of molybdosilicic acid, its preconcentration on polyurethane foam, elution in acetone (acetone: HCl = 99:1) and reduction to molybdenum blue form. The method is applicable up to 2 μg Si/ml. The minimum that was detected by this method was 5.0 ng Si/ml. The method yielded agreeable results.

A gravimetric method for determination of water in phosphate glasses

A simple gravimetric method for determination of water in phosphate glass systems has been developed. The method involves a chemical reaction between Al2O3 (used as a releasing agent) and acid phosphate of the glass system at 700° C. The reaction products have been found to be AlPO4 and H2O. The loss in weight due to expulsion of water has been directly measured. The selection of anhydrous Al2O3 as a releasing agent, optimum temperature and time of heating have been established from XRD and DTA. The ratio of releasing agent to sample (5:1) has been found to be adequate for release of water from the matrix. The method has been applied to the determination of water content of various glass systems, e.g. (i) ZnO—P2O5—H2O, (ii) ZnO-CaO-K2O—P2O5—H2O, (iii) MnO—K2O—P2O5—H2O. The results obtained compared favourably with the theoretical values.

A Rapid Complexometric Method for the Determination of ZnO, Al2O3 and P2O5 in Phosphate-Based Glasses

A rapid complexometric method has been developed for determination of ZnO, Al2O3 and P2O5 in zinc-phosphate glasses. Aluminium and zinc are determined in one aliquot, and P2O5 in another, from the same stock solution. The method is based on the complexation of both the metals with a known amount of EDTA. EDTA is then selectively released from Al-EDTA complex by NaF and titrated. The unreleased EDTA establishes zinc. The determination of phosphorus involves precipitation of phosphate with a known excess of lanthanum solution at 60°–70°C and back titration of the excess with EDTA at pH 5.3, zinc and aluminium being premasked with EDTA. Results obtained with synthetic solutions as well as glass samples following the method are quite agreeable to those obtained by the standard methods.

Rapid chelatometric determination of samarium and aluminium in the same solution and at the same pH after masking and demasking of aluminium with acetylacetone

A simple stepwise complexometric method with EDTA has been developed for the determination of samarium and aluminium in a single aliquot solution involving direct titration of Sm (III) at pH 5.3 and indirect titration of Al (III) at the same pH using xylenol orange as an indicator. Samarium is determined by direct titration with EDTA after masking aluminium with acetylacetone (at −20°C). Aluminium is determined indirectly with EDTA after demasking of aluminium with acetylacetonate at 90°C. Interferences due to Ti, Zr, Mn, Ni, Co, Cu etc have been eliminated. The method has been standardized against synthetic solutions and applied to various glasses.

Complexometric Titration of Zirconium and Yttrium in the same Solution for its Application in Zirconia-Yttria Ceramics

A simple stepwise complexometric method with EDTA has been developed for the determination of zirconium and yttrium in a single aliquot solution involving direct titration of zirconium at 1N HNO3 and 90°C and of yttrium at pH 5.3 using methyl thymol blue as indicator. Interferences due to Fe, Ti, Al and Cu have been eliminated by masking with acetylacetone. The method has been standardised against synthetic solutions and applied to various zirconia-yttria ceramics and other yttria bearing materials.