Tetsuro Murakami

Gas chromatographic—mass spectrometric determination of lower aliphatic tertiary amines in environmental samples

A method is described for determining lower aliphatic tertiary amines in environmental samples such as river water and bottom sediments. The method consists of distillation of aliphatic tertiary amines and determination by headspace gas chromatography—mass spectrometry. The detection limits for final 40-ml samples were 50 ng for trimethylamine, 10 ng for triethylamine, 5 ng for triallylamine, 10 ng for tripropylamine and 5 ng for tributylamine. The recoveries were over 70% and the relative standard deviations of the recoveries were below 12% (n = 5). The method is easy to operate, shows excellent sensitivity and selectivity and is applicable to environmental samples.

Capillary gas chromatographic-mass spectrometric determination of acid herbicides in soils and sediments.

A capillary gas chromatographic method with selected-ion monitoring (GC-SIM) was applied to eight common herbicides: 2-(4-chloro-o-tolyl-oxy)propionic acid, 3,6-dichloro-2-methoxybenzoic acid, 2-methyl-4-chlorophenoxyacetic acid, 2,3,6-trichlorobenzoic acid, 2,4-dichlorophenoxyacetic acid, 3,5,6-trichloro-2-pyridyloxy-acetic acid, 2,4,5-trichlorophenoxyacetic acid and alpha-(2-methyl-4-chlorophenoxy) butyric acid. The method involves extraction with saturated calcium hydroxide solution, esterification with pentafluorobenzyl bromide, clean-up with a silica gel column and determination by capillary GC-SIM. Recoveries from soil and sediment are over 89% (with the exception of 77% for TBA) with coefficients of variation below 5% (n = 7). The method is suitable for the simultaneous determination of the eight herbicides in environmental samples with high sensitivity and accuracy.

Photometric determination of selenium with ferrocene

A sensitive spectrophotometric method for the determination of selenium has been developed. The method depends on a redox reaction between selenious acid in 8M hydrochloric acid and a chloroform solution of ferrocene. One mole of selenious acid produces 4 moles of ferricenium ions, which are then oxidized by bromine water. The resulting iron(III) is reduced to iron(II) and determined with 1,10-phenanthroline. The relative standard deviation for 20 mug of selenium was 1.1%. The apparent molar absorptivity of the final solution, referred to selenious acid, is 4.23 x 10(4) 1. mole(-1). cm(-1) at 512 nm. This method has been used to determine selenium in copper metal.

Capillary gas chromatographic-mass spectrometric determination of pyridine bases in environmental samples.

A method is described for the determination of pyridine bases in environmental samples such as river water and bottom sediments. After distillation from environmental samples, the pyridine bases are concentrated on a rotary evaporator, extracted with n-hexane and determined by capillary gas chromatography-selected-ion monitoring (GC-SIM). The determination of twenty pyridine bases is possible using a 15 m X 0.53 mm I.D. capillary column coated with DBWAX (equivalent to PEG 20M) followed by SIM. The detection limits were 0.01-0.1 ng and recoveries from river water and bottom sediment were over 90% with coefficients of variation below 4% (n = 7) except for pyridine. This method is capable of the simultaneous determination of twenty pyridine bases with sufficient sensitivity and accuracy to be applicable to environmental samples.

Gas chromatographic determination of triclopyr in environmental waters

The reaction of BF3-trifluoroethanol with an extract of triclopyr from an acidified sample solution to form the trifluoroethyl ester has been applied to the determination of triclopyr in environmental waters. The product is cleaned up by silica-gel column chromatography and determined by gas chromatography with electron-capture detection.The detection and determination limits were 0.005 ng and 0.00025 µg ml–1, respectively. The recovery and coefficient of variation were found to be 90–93% and less than 4%, respectively (n= 7), for recovery experiments on river waters.

Determination of the herbicides frenock and dalapon in soil and river water by mass fragmentography

A method is described for determining frenock and dalapon in environmental samples such as river waters and soils, based on the reaction of 1-benzyl-3-p-tolyltriazene with an extract of frenock or dalapon from strongly acidified sample solutions to form benzylated species, which are subsequently analysed by mass fragmentography (with soil samples, steam distillation is applied prior to the extraction).Apiezon L grease-phosphoric acid serves as the stationary phase in GC and the molecular ions with m/z= 236 and 232 are used to monitor frenock and dalapon, respectively. The detection limits for frenock and dalapon are 0.05 and 0.5 ng, respectively, with 5 µl of sample injected. Recovery experiments using actual river water and soil samples showed recoveries of more than 92% with a coefficient of variation of less than 5%(n= 7). The method is capable of the simultaneous determination of frenock and dalapon with sufficient sensitivity and selectivity to be applicable to environmental samples.

Indirect spectrophotometric determination of sulfate with barium nitranilate.

An indirect spectrophotometric method for the determination of sulfate using barium nitranilate has been investigated. The analytical procedure is as follows: Add 30 mg of barium nitranilate to 5 ml of ethanolic solution (1 + 10) containing sulfate (525 μg) in a 10-ml stopped centrifuge tube. Shake for 5 min with mechanical shaker, and centrifuge the precipitate for 10 min at 300 rpm. Measure the absorbance of the supernatant liquid at 300 nm with a 1-cm quartz cell against a reagent blank. Beers law holds and the present method showed good reproducibility of relative standard deviation of 1.1 %, and the molar absorptivity for sulfate is 1.72 × 104 1mol-1 cm-1. Phosphate, thiosulfate, arsenate, chromate, sulfite, oxalate, calcium and strontium ions interfered with the determination of the analyte. The present method was applied to the determination of sulfate in tap water.

Determination of copper(II) by kinetic-catalytic oxidation of ferrocene

This paper reports on the photometric determination of copper (II) with 1,10-phenanthroline by the iron (III) formed from the oxidative decomposition of ferricenium ions