Kinuko Fujita

Applications of xanthene derivatives in analytical chemistry. Part LVII. Spectrophotometric determination of minocycline using gallium and Eosin

A spectrophotometric method for the determination of micro-amounts of minocycline (MINO) as a tetracycline derivative in weakly acidic media is proposed. It is based on the formation of a ternary complex between Eosin (sodium 2,4,5,7-tetrabromofluorescein), gallium and MINO in the presence of poly(vinyl alcohol). Under optimum conditions, minocycline hydrochloride (MINO.HCl) was determined in the range 0–40 µg in 10 ml of solution at 545 nm. The apparent molar absorptivity of MINO.HCl was 1.1 × 105 l mol–1 cm–1 with a Sandell sensitivity of 0.0047 µg cm–2 MINO.HCl. The method was applied to the determination of MINO.HCl in pharmaceutical preparations.

Highly sensitive spectrophotometric determination of cobalt using o-hydroxyhydroquinonephthalein and hydrogen peroxide in the presence of mixed surfactants

SummaryThe effects of cobalt(II) and surfactants on the decomposition of various xanthene dyes by hydrogen peroxide have been systematically investigated. A simple and highly sensitive spectrophotometric determination of cobalt(II) (0.05 ∼ 1.2 Μg/10 ml) is proposed. The method is based on the catalytic effect of cobalt(II) on the oxidation of o-hydroxyhydroquinonephthalein (Qnph) by hydrogen peroxide. The proposed catalytic spectrophotometric determination was sensitive, selective, reproducible and virtually unaffected by the presence of other ions; the effective molar “desorptivity” was 4.2×108 l/mol per cm, Sandell sensitivity was 0.15 pg/cm2, and the relative standard deviation was 3.2% at 0.6 ng/10 ml (n=5). The selective assays of cobalt(II) in water samples were also investigated with satisfactory results (95% ∼ 101%).

Application of Xanthene Derivatives in Analytical Chemistry Part LXV. The Spectrophotometric Determination of Vanadium with O-Hydroxyhydroquinonephthalein in the Presence of Cationic Surfactants

Abstract The colour reaction between o-hydroxyhydroquinonephthalein and vanadate ion in the presence of hexadecyltri-methylammonium chloride and L-ascorbic acid as a reductant was discussed. And the spectrophotometric determination of vanadium utilizing the colour reaction system in micellar media was proposed at about pH 5.4. Beers law was obeyed in the concentration range 0-8 μg of vanadium at 540 nm. The apparent molar extinction was 8.7 × 10 4 1 mol−1 cm−1 with Sandell sensitivity of 0.0006 μg/cm2. This proposed method was relatively simple and sensitive, and then its applications for the waste water, river water, rain water, etc. were discussed.

Xylenol Orange, Zirconium(IV) and Fluoride Color Reaction in Mixed Micelles of N-Hexadecylpyridinium Chloride and Brij 35, and Its Analytical Application1

Abstract The color reaction between Xylenol orange (XO), zirconium (IV) and fluoride ions in the presence of various surfactants alone or in combination was studied at various pH. The XO -zirconium)IV)-fluoride ion ternary complex in mixed micellar media containing a low concentration of N-hexadecylpyridinium chloride (HPC) as a cationic surfactant and large amounts of (poly{oxyethylene)dodecyl ether (Brij 35) as a nonionic surfactant at weakly acidic media was found to be the most stable, and showed a remarkable bathochromic shift and clear contrast against a reagent blank. The maximum absorbance was at 600 nm in the mixed micellar media at pH 3.5, and the apparent molar absorptivities at 600 nm were 7.0 × 104 1 mol−1 cm−1 for zirconium(IV) and 1.4 × 104 1 mol−1 cm−1 for fluoride ion. The calibration curves covered the ranges of 0.5 ∼ 20.0 μg/10 ml zirconium! IV) and 0 ∼ 20.0 μg/10 ml fluoride ion with the Sandell sensitivities being 0.0013 μg/cm2 for zirconium(IV) and 0.0016 μg/cm2 for fluoride ion.

Fluorescence reaction between o-hydroxyhydroquinonephthalein and vanadium in micellar media, and its application

SummaryThe formation of complexes amongst vanadium, o-hydroxyhydroquinonephthalein (Qnph), or/and chlorpromazine hydrochloride (CP · HCl), as a phenothiazine drug, in non-ionic surfactant micellar media was fluorometrically investigated in weakly acidic media. Fluorometric methods for the determination of vanadium and CP · HCl were respectively established by measuring the difference of relative fluorescence intensities (ΔF) between Qnph and Qnph-vanadium solutions, andΔF between Qnph-vanadyl and Qnph-vanadyl-CP · HCl solutions at an emission wavelength of 540 nm with excitation at 400 nm in the presence of polyvinyl alcohol (PVA) micelles. The calibration graphs were linear in the ranges of 0–0.5 μ vanadium and 0–220 μg CP · HCl per 10 ml of aqueous solution. The relative standard deviations (5 replicates) were 2.5% for 0.2 μg vanadium and 1.3% for 100 μg CP · HCl per 10 ml of aqueous solution, respectively. The applications to assays of vanadium in water and CP · HCl preparations were investigated, and the results were relatively good.

Spectrophotometric determination of bismuth(III) with o-hydroxyhydroquinonephthalein in the presence of Brij 58

A simple and sensitive spectrophotometric determination of bismuth(III) is based on the reaction between bismuth(III) and o-hydroxyhydroquinonephthalein in the presence of Brij 58 in acidic media. The calibration graph is linear over the range 0-3.5 mug/ml bismuth(III) in the final solution, and the apparent molar absorptivity at 520 nm is 9.03 x 10(4) l. mole(-1). cm(-1). The proposed method is 2-10 times more sensitive than other methods, and simpler. It has been applied to the assay of bismuth(III) in pharmaceutical preparations, such as dermatol and bismuth subnitrate, with good results.

The Spectrophotometric Determination of gallium (III) Using O-Hydroxyhydroquinonephathalein in the Presence of Surfactant Micellar

Abstract The color reaction systems between various metal ions and o-hydroxyhydroquinonephthalein(Qnph) as a xanthene dye, in the presence of various water soluble surfactants(cationic. anionic, non-ionic surfactants) alone or in combination, were systematically investigated at various pH areas. The coexistence of cationic and non-ionic surfactants, such as Zephiramine (Zp) and Brij 35, was most effective for the color reaction systems between Qnph and gallium(III), as a metal ion, at weakly acidic media. By using the color reaction between Qnph and gallium(III) in the coexistence of Zp and Brij 35, an improved and sensitive spectrophotometric determination of gallium(III) was proposed as method 1, and the calibration curve was rectilinear in the range of 0∼7.0 μg of gallium(III) in a final solution of 10ml at pH 6.4. The apparent molar absorptivity was 1.5 × 105 1 mol−1 cm−1 at 560 nm, and the interference of foreign ions was decreased by ½∼ ¼-fold in comparison with other methods; method 3—in the presen...

Color reaction between 4-(2-pyridylazo)resorcinol and mercury(II) in the presence of surfactant, and improved spectrophotometric determinations of mercury(II) and cyanide ion with its coloring

Abstract The reactions among 4-(2-pyridylazo)resorcinol (PAR), mercury(II) and/or cyanide ion in the presence of water soluble surfactants alone or combination were systematically investigated at about pH 9. The spectrophotometric determinations of mercury(II) and cyanide ion were investigated by using the PAR-mercury(II)-HPC complex (3:2:2 molar ratio) in the presence of N-hexadecylpyridinium chloride (HPC) alone; calibration graphs were rectilinear in the ranges of 0 – 40 μg mercury(II) and 0 –10 μg cyanide ion in a final 10 ml with the apparent molar absorptivities of 5.9 × 104 for mercury(II) and 2.5 × 104 1 mol−1 cm−1 for cyanide ion at 590 nm. The proposed method had advantages—rapidity, simplicity without solvent extraction, and sensitivity in comparison with reported solvent extraction methods. The interference of foreign ions decreased 1/2–l//4-fold compared with that in the presence of non-ionic surfactant alone.

Spectrophotometric Determination of Nitrite Ion or Chloramine T with Gallein-Molybdenum Complex and Cobalt (II) with Gallin and Hydrogen Peroxide in a Micellar Media

Abstract A simple and sensitive spectrophotometric method for the determination of nitrite ion or chloramine T is proposed utilizing a gallein-molybdenum complex in the presence of N-hexadecyltrimethylammonium chloride in acidic media. Also, a sensitive catalytic spectrophotometric procedure for determi

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

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. Beers law was obeyed over the range 0 to 90..mu..g of Th(IV) and 12 to 35..mu..g of citrate ion, in a final volume of 10 ml. The Sandell sensitivities were estimated to be 0.0013 ..mu..g/cm/sup 2/ Th(IV) and 0.0005 ..mu..g/cm/sup 2/ citrate ion at 600 nm. The analytical procedures were simple and did not require any organic solvent extraction.