| Research Abstract |
(1) Theoretical studies on the retention and peak formation mechanism in ion chromatography (IC) : Following on from our previous work, a new theory "selective peak enhancement and suppression of conductivity detection IC" was evaluated. This theory was effectively used in the determination of trace level orthophosphate in sewage samples. Ion exchange chromatographic behavior of polyvalent eluent systems was evaluated theoretically by introducing a new parameter "the intereluent separation factor" in equations for Hoover's model.
(2) Functional eluents for photometric detection IC : Both[Cu(en)_2SO_4 and[Cu(trien)]SO_4 were effective eluents for the sensitive determination of cations. Using a Na_2[Cu(edta)]- Na_2H_2 edta eluent, not only anions but also metal ions were deterifined as metal-edta anion chelates by photometric detection IC. These methods were effectively used in the determination of cations and anions in environmental water samples. Malic acid enantiomers were separately d
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etermined by photometric detection IC using a copper - tartaric acid complex eluent, based on a ligand-exchange formation mechanism. Malic acid, an apple juice additive, was determined by this method.
(3) Determination of carbonate-carbon : Interfering atmospheric carbon dioxide dissolved in eluents was removed effectively by nitrogen purging. Using this equipment, trace level carbonate carbon as low as 10^<-6> M could be determined by photomeric detection IC as well as ion exclusion chromatography (conductivity detection). Carbonate-carbon in rain water was determined by this method.
(4) Polarized photometric detection : When two polarizers were set on both sides of the flow sell of an absorbance detector, the intensity of natural light transmitted through the polarizers and the flow cell was changed according to the optically active compounds if passed through. The change in absorbance was in proportion to the concentration of the compound. Nonchromophoric optically active compounds such as sugars were sensitively determined using photometric detection HPLC without any derivatization.
(5) Automatic pretreatment/HPLC system : The combination of column-switching system and a heart-cutting technique effectively removed interfering compounds in IC. This system was used to determine anions in river and rain water samples by photometric detection IC and orthophosphate in sewage samples by conductivity detection IC.
(6) Determination of nitopyrenes by HPLC with chemiluminescence detection : A method of determining nitro-, nitroso- and aminopyrenes has been developed using HPLC with chemiluminescence detection after on-line electrochemical reduction. Determination method of 1, 3-, 1, 6-, 1, 8-dinitropyrenes and 1-nitropyrene has also been developed using HPLC with chemiluminescence detection after off-line chemical reduction. Utilizing these methods, dinitropyrenes and nitropyrene were determined in diesel- and gasoline-engine exhaust particulates. Less
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