Ryuzo Takeshita

Determination of trace azaarenes in water by gas chromatography and gas chromatography—mass spectrometry

Abstract The method in which trace two-, three- and five-ring azaarenes in water samples can be determined was investigated by gas chromatography (GC). The trace azaarenes in water were concentrated with an Amberlite XAD-2 resin column and separated into azaarenes with two and three rings and those with five rings by a solvent extraction, followed by a clean-up procedure using an alumina column. The azaarenes thereby separated were determined by GC with a flame thermionic detector (GC—FTD) and GC—mass spectrometry with a selected ion monitor detector (GC—MS—SIM). Detection limits of the azaarenes by GC—FTD were in the range 0.5–3 ng and those of GC—MS—SIM in the range 0.02–0.5 ng. Utilization of GC-MS-SIM was very useful for the determination of trace azaarenes in environmental samples.

Separation and detection of water-soluble acid dyes on polyamide thin layers

Abstract A method is described in which twenty water-soluble acid dyes, isolated from food products by means of DEAE-Sephadex, were detected by thin-layer chromatography using polyamide plates. The isolation procedure involved shaking samples with the Sephadex and then eluting the dyes by column chromatography. In polyamide thin-layer chromatography, the solvent system suitable for the separation of the dyes was pyridine—methanol—28% aqueous ammonia—water (5:6:1:16). This is a simple and rapid method for the detection of acid dyes in cellulosic and proteinaceous samples, especially when the dyes are present in low concentrations.

Control of PCDD and PCDF formation in fluidized bed incinerators

Abstract The object of this study was to know how the formation of PCDDs and PCDFs in fluidized bed incinerators could be controlled. Therefore the relationship between levels of hydrogen chloride in flue gas in municipal waste combustion and PCDDs and PCDFs formed thereby was investigated. In order to decrease the concentration of formed hydrogen chloride in the gas, Dolomite was supplied into the furnace. When the supplied amounts of Dolomite were increased, the concentration of hydrogen chloride in the gas at the outlet of the electrostatic precipitator (EP) were clearly decreased. PCDDs and PCDFs in the boiler and the EP ash samples and in the gas samples were found at lower levels in proportion to the decrease of levels of hydrogen chloride in the gas.

Relationship between the formation of polychlorinated dibenzo-p-dioxins and dibenzofurans and the control of combustion, hydrogen chloride level in flue gas and gas temperature in a municipal waste incinerator

Abstract The control of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/Fs) formation was investigated in a municipal waste incinerator equipped with the electrostatic precipitator (EP). The simultaneous control of combustion, hydrogen chloride (HCl) concentration level in the flue gas and the gas temperature proved very effective in the control of PCDDs/Fs formation, reducing the concentration levels of PCDDs/Fs in the flue gas at the EP outlet to 0.2 ng/Nm3 as 2,3,7,8-tetrachlorodibenzo-p-dioxin when evaluated by the international toxicity equivalent factors.

Detection of mercury and alkylmercury compounds by reversed-phase thin-layer chromatography

Abstract A reversed-plate thin-layer chromatographic method for separation and detection of the dithizonates of inorganic mercury compounds and a series of alkyl-mercury compounds (C1C18) was investigated. The specificity of this method was that all the compounds tested were distinctly separated and detected with high sensitivity. The influence of some of the other inorganic metals and excess dithizone was also examined. The method is applicable to the separation and identification of mercury compounds in foods and sewages.

Leaching of polychlorinated dibenzo-p-dioxins and dibenzofurans in fly ash from municipal solid waste incinerators to a water system

In order to predict how much polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/Fs) are leached from fly ash by rain water when fly ash is disposed, leaching of PCDDs/Fs from a fly ash obtained from a municipal solid waste incinerator (MSWI) was investigated by packing the ash in a column and eluting with water. In the beginning of the elution, PCDDs/Fs associated with water-soluble particulates in the ash were eluted, whereas in the latter half, those associated with water slightly soluble particles were eluted, judging from the comparison of PCDDs/Fs in eluate fractions with those transferred to solutions from the original ash by stepwise batch methods with water and 2N hydrochloric acid.The amounts of PCDDs/Fs eluted from the ash column were 2.9% and 1.7% of those extracted from the original ash, respectively, while large amounts of PCDDs/Fs were contained in the fly ash in the column after the elution, suggesting that PCDDs/Fs in water-insoluble particulates of the ash would not be eluted by water.

Micro-determination of total phthalate esters in biological samples by gas-liquid chromatography.

A method was investigated in which all of the phthalate esters in biological samples were determined as phthalic acid by gas-liquid chromatography. The method is based on the separation of phthalate esters from the sample with n-hexane, saponification of the esters with an alkaline ethanolic solution to give phthalic acid, purification of the acid by extraction with diethyl ether and column chromatography using silica gel, and conversion of the acid into bis(2,2,2-trifluoroethyl) phthalate with a 2,2,2-trifluoroethanol solution containing boron trifluoride. The derivative obtained is highly sensitive to an electron-capture detector, giving a sensitivity of 0.1 pg. Biological samples fortified with di(2-ethylhexyl) phthalate at levels of 5-100 ppb were analyzed, with recoveries of 70-100%.

Application of column and thin-layer chromatography to the detection of artificial sweeteners in foods.

Abstract A method for the purification and detection of three artificial sweeteners, saccharin, cyclamate and dulcin, in food products is described. It was developed on the basis of the separation of the sweeteners from other impurities by extraction with ethyl acetate and by adsorption on and elution from silica gel and alumina columns, followed by thin-layer chromatography using polyamide. The sweeteners were detected on the chromatograms by observation with three chromogenic spray reagents having sensitivity ranges from 0.01 to 2 μg of the sweeteners. Various foods containing levels of 10–100 p.p.m. and artificially sweetened foods were successfully analysed for the sweeteners.

Identification of phenolic compounds in fly ash from municipal waste incineration by gas chromatography and mass spectrometry

Fly ash obtained from a municipal solid waste incinerator (MSWI) was analyzed for phenolic compounds by Gas Chromatography/Mass Spectrometry (GC/MS). After the treatment of the fly ash with HCl, phenolic compounds in the ash were extracted with benzene from both residual fly ash and the acidic solution and they were separated by partition extraction of the extract using HCl, and NaOH and NaHCO3 solutions. The extract was cleaned up and separated into four fractions by silica gel column chromatography. Phenolic compounds in the fractions were identified by GC/MS. Many unknown phenolic compounds were found in the fly ash.

Detection of sodium alkanesulphonates and alkyl-benzenesulphonates by polyamide thin-layer chromatography

A thin-layer chromatographic method was investigated in which two series of sodium alkanesulphonates (C4-C18) and alkylbenzenesulphonates (C0-C14) were separated. All of the compounds tested were clearly separated on polyamide layers with aqueous ammonia-pyridine and aqueous ammonia-pyridine-methanol systems and detected with high sensitivity by spraying with a pynacryptol yellow reagent and then observing under UV light (253.6nm).