Haruo Miyata

Determination of sulfate in river water by flow injection analysis

Abstract Sulfate ion in river water is determined by flow injection analysis at a rate of 30 samples per hour; the sulfate contents are typically less than 30 ppm. The reagent solution contains dimethylsulfonazo-III, barium chloride, potassium nitrate and chloroacetate buffer in 70% ( v v ) ethanol, and is saturated with barium sulfate. The aqueous carrier stream is also saturated with barium sulfate. The sample is filtered and treated with Amberlite IR120-B cation-exchanger before injection into the carrier stream, and the decoloration of the barium—dimethylsulfonazo-III complex by sulfate is measured at 662 nm. The calibration graph is linear over the range 0–30 μg ml-1 for sulfate in water.

Spectrophotometric determination of anionic surfactants in river waters using 1-(4-nitrobenzyl)-4-(4-diethylaminophenylazo)-pyridinium bromide

Nitro, bromo and methyl derivatives of 1-(benzyl)-4-(4-diethylaminophenylazo)pyridinium bromide were synthesised and evaluated as new cationic reagents for the determination of anionic surfactants. These reagents were very stable and reacted with anionic surfactants, such as alkylbenzene-sulphonate and alkylsulphate, to form a 1 : 1 stable ion associate, which was extracted into chlorobenzene in a single extraction. The apparent molar absorptivity of the ion associate of the 4-nitro derivative with sodium di(2-ethylhexyl)sulphosuccinate was 6.10 × 104 l mol–1 cm–1(at 573 nm) in chlorobenzene. 1-(4-Nitrobenzyl)-4-(4-diethylaminophenylazo)pyridinium bromide was used in the determination of µg l–1 levels of anionic surfactants in river water. The results were compared with the methylene blue method (Japanese Industrial Standard method) for river waters. This method is designed to determine anionic surfactant concentrations in solution.

The reaction of dicarboxylic acids containing ether linkages with alkaline earth metals

Abstract Four dicarboxylic acids (Reagents I, II, III and IV) containing ether linkages, HOOCCH2O-(CH2CH2O)nCH2COOH (n = 0–3), were synthesized. The acid dissociation constants and their chelate stability constants with alkaline earth metals were measured by pH titration method at an ionic strength μ = 0·10 and at 25·0 ± 0·1°C. As the total sum of the number of oxygen atoms of ether linkages and carbon atoms approaches infinity, the value of the ratio of the first to the second acid dissociation constant comes near to four. Therefore, it indicates that the molecules behave statistically, when the number of atoms between two carboxyl groups approaches infinity. The decreasing order of the stability constants of those chelates with alkaline earth metals is as follows: Reagents I and II (n = 0 and 1; Ca

Some N-alkyl-naphthylazo pyridinium salts as new reagents for the spectrophotometric determination of anionic surfactants

SummaryEleven pyridinium azo dyes with straight-chain alkyl groups CnH2n+1−(n=6−18) and bromoalkyl groups BrCmH2m−(m=6−12) were synthesized with the intention of developing reagents for the determination of low levels of anionic surfactants in an aqueous medium. The effect of the alkyl chain length of these reagents on the reactivity with anionic surfactants such as sodium dodecylsulphate (SDS), sodium linear-dodecylbenzenesulphonate (DBS), sodium dodecylsulphonate (DS) and sodium laurate (SL) was studied. It was found that the alkyl chain length played an important role in the formation of ion associates and the composition of the ion associates formed. These reagents were classified into four groups with respect to the reactivity with anionic surfactants. The first group (n,m=6) reacts only with DBS. The second group (n,m=8) reacts with SDS, DBS and DS. The third group (n,m=10, 12) reacts with SDS, DBS and DS; however, the colour intensity of the DBS-ion associate was unstable. The fourth group (n=14, 16, 18) reacts with all anionic surfactants examined, and the composition of the ion associates with SDS and DS was 2:1 ([reagent]/[surfactant]) though that of the ion associates of the three reagent groups mentioned above was 1:1. The optimal conditions for the determination of anionic surfactants in river water with 1-octyl-4-(4-aminonaphthylazo)-pyridinium bromide was examined. The calibration graph was linear up to 3×10−6 mol/l, and the apparent molar absorptivity of the ion associate was 3.8×104 l mol−1 cm−1 (at 427 nm). The relative standard deviation for 2.4×10−6 mol/l SDS was 4.9%. Recoveries of 88–107% were found for 8.0×10−7 mol/l SDS in river water samples.

Spectrophotometric determination of anionic surfactants in tap and river waters with 1-(10-bromodecyl)-4-(4-aminonaphthylazo)-pyrimidinium bromide

SummaryA new cationic dye, 1-(10-bromodecyl)-4-(4-aminonaphthylazo)-pyridinium bromide, was synthesized and evaluated as a new reagent for the determination of anionic surfactants. The reagent reacts with anionic surfactants, such as sodium dodecylsulphate and sodium dodecylbenzenesulphonate, to produce an ion associate in an aqueous medium. The colour change occurs simultaneously, and the colour development is very stable. This makes it possible to determine anionic surfactants directly by spectrophotometry without solvent extraction. The stoichiometric ratio of the ion associate was found to be 1:1 by the mole ratio method. The calibration graph was linear up to 2.5×10−6 mol/l. The apparent molar absorptivity of the ion associate was 5.3×104 l mol−1 cm−1 (at 595 nm). The relative standard deviation (n=10) for 1.2×10−6 mol/l sodium dodecylsulphate was 4.9%. The proposed method was applied to the determination of anionic surfactants in tap and river waters.

Simultaneous determination of sodium dodecyl sulphate and sodium linear-dodecylbenzenesulphonate with 1-stearyl-4-(4-aminonaphthylazo)-pyridinium bromide by spectrophotometry

A rapid and sensitive spectrophotometric method for the simultaneous determination of sodium dodecyl sulphate (SDS) and sodium linear-dodecylbenzenesulphonate (DBS) with 1-stearyl-4-(4-aminonaphthylazo)-pyridinium bromide (SAPB) is described using the difference at the maximum absorption wavelength of the SDS- and the DBS-ion associate. SDS and DBS have been determined independently by measuring their respective absorbances at the maximum absorption wavelength. The apparent molar absorptivities of the SDS- and the DBS-ion associate are 8.0×104 l mol−1 cm−1 at 445 nm and 4.5×104 l mol−1 cm−1 at 424 nm, respectively. The calibration graph for SDS is linear in the range from 0.1 to 1.0×10−6 mol/l in the presence of 1.2×10−6 mol/l DBS and for DBS from 0.8 to 2.0×10−6 mol/l in the presence of 8.0×10−7 mol/l SDS. The relative standard deviation (n=15) for 8.0×10−7 mol/l SDS is 3.4% and for 1.6×10−6 mol/l DBS 2.1%. The proposed method has been applied to the simulatenous determination of SDS and DBS in river water samples.

Study on the coextraction of scandium-yttrium-lumogallion complex

Abstract The coextraction of scandium-yttrium-lumogallion [LMG; 4 - chloro - 6 - (2,4 - dihydroxyphenylazo) - 1 - hydroxybenzene - 2 - sulfonic acid] into diethyl ether has been studied. The acid dissociation constants of LMG, p K a2 and p K a3 were estimated to be 6.24 and 8.05 respectively. The composition of the complex extracted was determined by using the radioisotopes 46 Sc and 90 Y and by spectrophotometry of LMG and the ratio of the components was Sc:Y:LMG = 1:1:3. The coextraction scheme was discussed briefly.

A Spectrophotometric Study of the Thorium Complexes of o-, m-, and p-Nitrophenyl-azo-chromotropic Acids

o-, m-, and p-Nitrophenyl-azo-chromotropic acids were prepared as colorimetric reagents for thorium. The acid dissociation constants of the reagents have been determined spectrophotometrically, their pK1 values being 8.96, 8.60, and 8.77 for the and o-, m-, and p-compounds respectively at 25°C and when μ=0.1. The reagents form violet 1 : 1 complexes in an acidic solution. The apparent stability constants have been measured spectrophotometrically. The order of the apparent stability constants of the complexes agrees with that of the first acid dissociation constants of the reagents; m-nitro>p-nitro>o-nitro compounds.