Takako Matsuo

Selective and sensitive fluorometric determinations of cobalt(II) and hydrogen peroxide with fluorescein-hydrazide

Fluorophotometric determinations of cobalt(II) and hydrogen peroxide were investigated by using the fluorescence reaction between fluorescein-hydrazide (fl-NHNH(2)), and/or hydrogen peroxide, cobalt(II), respectively. The calibration graphs were liner in the range of 0-6.0 ng cobalt(II) and 0-1000 ng hydrogen peroxide per 10 ml at an emission wavelength (E(m)) of 530 nm with an exicitation wavelength (E(x)) of 508 nm, respectively. These proposed methods were selective and simple, and the effect of foreign ions was negligible in comparison with conventional reported methods such as nitroso R,4-(2-pyridylazo)resorcinol(PAR), alizarin, pyridine-2-aldehyde-2-pyridinehydrazone, stilbazo-cobalt(II), etc.

Sensitive spectrophotometric determination of human serum albumin(HSA) with (2-(5-bromo-2-pyridylazo)-5-(N-phenyl-N-sulfopropylamino)phenol) (5-Br.PAPS)-cobalt(II)) complex

Abstract A sensitive and selective spectrophotometric determination of human serum albumin(HSA) was proposed by using the ternary complex-formation reaction among 2-(5-bromo-2-pyridylazo)-5-(N-phenyl-N-sulfopropylamino)phenol (5-Br.PAPS) as a pyridylazo derivative, cobalt(II) and HSA in the presence of poly(N-vinylpyrrolidone) (PVA) as a dispersion agent. The calibration curve was linear in the range of 0 - 7.0 μg/ml HSA by measuring the difference of absorbances at 636 nm between ((5-Br.PAPS)-cobalt(II)-HSA) and (5-Br.PAPS-cobalt(II)) solutions. The sensitivity was > 6-fold over the (Pyrogallol Red(PR)-molybdenum(VI)) method, and the recovery test in urine was satisfactory (97.5 ± 2.8%).

Selective and sensitive spectrophotometric determination of copper(II) and benzoylperoxide with N-ethyl-2-naphthylamine☆

Spectrophotometric determinations of benzoylperoxide (BPO) and copper(II) were, respectively, investigated by using the colour reaction for N-ethyl-2-naphthylamine (NENA), BPO and copper(II) as a metal ion in various concentrations of acetonitrile-water mixed solution as acidic media. The calibration graphs were linear in the range of 0-200 mug BPO with apparent molecular coefficient (epsilon) of 8.5 x 10(3)M(-1) cm(-1) at 530 nm, and 0-2.4 mug per 10 ml copper(II) with epsilon = 1.72 x 10(5)M(-1) cm(-1) at 533 nm, respectively. Additionally, the FIA method for copper(II) was proposed with NENA-BPO. The calibration graph for FIA was linear in the range of 0-7.9 ng copper(II) per 5 mul at 533 nm. These proposed methods were selective and simple in comparison with previous methods such as cuproin kinetic reactions, especially the spectrophotometry for copper(II) with NENA-BPO was very specific, and the effect of foreign ions was negligible.

Selective spectrophotometric determination of palladium(II) with 2(5-nitro-2-pyridylazo)-5-(N-propyl-N-3-sulfopropylamino) phenol(5-NO2.PAPS) and tartaric acid with 5-NO2.PAPS-niobium(V) complex

Spectrophotometric determinations of palladium(II) and tartaric acid were respectively investigated by using the color reactions between 2(5-nitro-2-pyridylazo)-5-(N-propyl-N-3-sulfopropylamino)phenol(5-NO(2).PAPS) and palladium(II) in strong acidic media, and between 5-NO(2).PAPS, niobium(V) tartaric acid in weak acidic media. The calibration graphs were linear in the range of 0-25 microg/10 ml palladium(II), with an apparent molecular coefficient (epsilon) of 6.2 x 10(4) l mol(-1) cm(-1) at 612 nm, and 0-23 microg/10 ml tartaric acid with epsilon=1.08 x 10(6) l mol(-1) cm(-1) at 612 nm, respectively. The proposed methods were selective and sensitive in comparison with other chelating pyridylazo dyes-palladium(II) or metavanadic acid-tartaric acid method, and the effect of foreign ions such as copper(II) was negligible for the assay of palladium(II) with 5-NO(2).PAPS.

Preconcentration of 1-(2-pyridylazo)—2-naphthol—iron(III)-capriquat on a membrane filter, and third-derivative spectrophotometric determination of iron(III)

Iron(III) was preconcentrated by collection on an organic solvent-soluble membrane filter (nitrocellulose (NC)) of the iron(III)-1-(2-pyridylazo)-2-naphthol (PAN) complex in the presence of capriquat as an oily quaternary ammonium salt. Third-derivative spectrophotometry was used for measurement of the third-derivative distance (d(3)A/dlambda(3)) between lambda(1) = 520 nm and lambda(2) = 590 nm or lambda(3) = 660 nm and lambda(4) = 724 nm of the iron(III)-PAN-capriquat complex or PAN-capriquat in dimethylsulfoxide (DMSO) following preconcentration. The calibration curve was linear in the range of 1-10 mug iron(III)/5.0 ml DMSO solution. The proposed method was about five-fold more sensitive and more selective than using zero-order spectrophotometry.

Sensitive Spectrophotometric Determination of Benzoylperoxide with N,N,N′,N′-Tetramethyl-p-phenylenediamine

Abstract A highly sensitive spectrophotometric determination of benzoylperoxide (BPO) based on the color developing reaction between N,N,N′,N′-tetramethyl-p-phenylenediamine (TMPD) and BPO in the presence of cerium(IV) in weakly acidic media is proposed. The calibration graph is linear in the range 0–6000 ng BPO per 10 ml with an apparent molar absorptivity of 4.73 × 105 1 mol−1 cm-1 at 612 nm. The proposed method is about 50-fold more sensitive than N-ethyl-2-naphthylamine (NENA), and application to assays of flour is described.

Spectrophotometric Determination of Palladium(II) with O-Sulfophenylfluorone in the Presence of N-Hexadecyltrimethylammonium Chloride

Abstract Simple and sensitive spectrophotometric determination of palladium(II) with O-sulfophenylfluorone(SPF) was proposed in the presence of N-hexadecyltrimethylammonium chloride(HTAC) as a cationic surfactant. The calibration graph was linear up to 1.2 μg/ml palladium(II) by measuring the absorbance at 585 nm against a reagent blank. The apparent molar extinction coefficient (∊) was 1.2 × 105 1 mol−1 cm−1 and Sandells sensitivity was 0.00096 μg/cm2 palladium(II) at 585 nm. The effect of foreign cations or anions was partially examined.

New and Sensitive Spectrophotometric Determination of Gold(III) with N,N-Dimethyl-p-Phenylenediamine and Potassium Persulfate

Abstract From the color developing reactions of various phenylenediamine derivatives (I)-(V), oxidizing agent and gold(III). the combination of N,N-dimethyl-p-phenylenediamine (DPD)(II) and potassium persulfate in acidic media was used for a simple and sensitive spectrophotometric determination of gold(III). The calibration graph was linear in the range of 0–300 ng/10 ml gold(III) with a molar absorptivity of 1.9 × 106 l mol−1 cm−1 at 552 nm. The proposed method had higher sensitivity than other spectrophotometric methods, and was applied to the assay of gold(III) in gold-pharmaceuticals such as sodium aurothimaleate and auranofin. The results were satisfactory.

Spectrophotometric Determination of Hydrogen Peroxide with 2-(5-Bromo-2-pyridylazo)-5-(N-propyl-N-sulfopropylamino)phenol-molybdenum(VI), or 2-(5-Nitro-2-pyridylazo)-5-(N-propyl-N-sulfopropylamino)phenol-vanadium(V) in the Presence or Absence of Surfactant

Abstract A spectrophotometric determination of hydrogen peroxide (H2O2) was proposed with 2-(5-bromo-2-pyridylazo)-5-(N-pro-pyl-N-sulfopropylamino)phenol(5-Br.PAPS)-molybdenum(VI) complex at pH 1.9, 2-(5-nitro-2-pyridylazo)-5-(N-propyl-N-sulfopropylamino)phenol (5-NO2. PAPS)-vanadium(V) complex at pH 0.9 or 6.2 in the presence of anionic or cationic surfactant, sodium dodecylbenzenesulfonate (SDBS) or hexadecyltrimethylammonium chloride (HTAC). The calibration curves were linear in the range of 0–2.5 × 10−5 M(0–8.5 μg/10 ml) H2O2 or 0–2.0 × 10−5 M(0–6.8 μg/10 ml) H2O2 with apparent molar absorptivities (∊) 4.6 × 10−4 1 mol−1 cm−1 at 640 nm(5-Br.PAPS-molybdenum(VI) complex), 7.7 × 10−4 1 mol−1 cm−1 at 600 nm(5-NO2. PAPS-vanadium(V)-SDBS complex) and 9.2 × 10−4 1 mol−1 cm−1 at 605 nm(5-NO2 PAPS-vanadium(V)-HTAC complex), respectively.

Selective spectrophotometric determination of gallium(III) with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol in the presence of sodium dodecylsulfate and brij 35

ABSTRACT For a selective spectrophotometric determination of gallium(III) without interference of aluminium(III), firstly, the color developments between gallium(III) and various chelating azo-dyes; 4(2-pyridylazo) resorcinol (PAR), 2-(5bromo-2-pyridylazo)-5-diethylaminophenol (5-Br.PADAP) in the presence or absence of surfactant alone; cationic-, anionic-, nonionic-surfactants or surfactant combination; cationic-nonionic-, anionic-nonionic-, cationic-anionic mixed surfactants, were systematically investigated. From these color developments, 5-Br.PADAP in tested azo-dyes, and surfactant-combination of sodium dodecylsulfate (SDS) as an anionic surfactant and Brij 35 ((polyoxyethylene)dodecylether) as a nonionic surfactant was selected for a selective assay of gallium(III) in the coexistence of aluminum(III). The calibration graph was linear in the range of 0-9.0 μg/10 ml gallium(III) by measuring the absorbance at 575 nm of 5-Br.PADAP-gallium(III) color development in the coexistence of SDS and Brij 35, an...