服部 幸和

A sensitive, selective and rapid analytical method was developed for the determination of 4, 6-dinitro-o-cresol (DNOC) and 2, 6-dinitro-p-cresol (DNPC) in environmental water samples by liquid chromatography/tandem mass spectrometry (LC/MS/MS). Trace amounts of DNOC and DNPC in water samples adjusted to pH3 were collected on an Autoprep PS-Liq@ cartridge (PS-Liq cartridge) at flow rate of a 50ml · min^-1 and then eluted with 5ml of acetonitrile. The targets were separated with a reversed-phase column (ODS-3, 2.1 mm x 150mm, and 5μm) and measured by mass spectrometry operated in the electrospray ionization (ESI)-negative mode. The method detection limit (MDL) was 0.24ng · l^-1 for DNOC and 0.49ng · l^-1 for DNPC. The method was then applied to the environmental water samples from Osaka Prefecture. The concentrations of DNOC were 2.1∼74ng · l^-1 and those of DNPC were n.d.∼43ng · l^-1.

Measurement of acrolein and other aldehydes in ambient air was carried out at the Research Institute of Environment, Agriculture, and Fisheries in Osaka city from May 11 to 19 in 2007. The aldehydes were collected as their derivatives of O-(4-cyanoethoxbenzyl) hydroxylamine (CNET), and determined by liquid chromatography/tandem-mass spectrometry (LC/MS/MS). The concentrations of acrolein, 0.04∼0.49μg/m³, showed the positive correlations with nitrogen monoxide (NO), nitrogen dioxide (NO₂), nitrogen oxides (NO_x), carbon monoxide (CO), and non-methane hydrocarbons (NMHC). On the other hand, it showed the negative correlation with oxidant (O_x). These results suggested that acrolein exhausted from motor vehicles, increased in the morning and midnight, and was easily decomposed under sunlight by photochemical reaction.<BR> Formaldehyde showed a different behavior from acrolein. It showed the positive correlation with oxidant (O_x) generated with the photochemical reaction, and thus increased in the daytime.

A sensitive and selective method was developed for the determination of acrolein in ambient air by using liquid chromatography/tandem-mass spectrometry (LC/MS/MS). Air was sampled by passing through an O-(4-cyano-2-ethoxbenzyl) hydroxylamine (CNET) cartridge for 2∼24 hrs at a constant flow rate (200 mL/min). The acrolein-CNET derivative eluted from the cartridge with acetonitrile was separated by a reversed phase liquid chromatography and determined by LC/MS/MS in turbo spray ionization (ESI) positive mode. The collection efficiency of acrolein on a CNET cartridge was more than 99 %. The method detection limit was 0.4 ng/m³ in case of sampling volume of 0.3 m³ and relative standard deviation of repeated analysis was 5.0 %. Recoveries of acrolein on CNET cartridges under the condition of the relative humidity of 30∼87 % at the temperature of 25∼35 °C were 82∼92 %. In a refrigerator, acrolein-CNET derivative was stable for about 5 days on the cartridge, and that in the solution eluted with acetonitrile was stable for one month.<BR>This method was applied to the determination of ambient acrolein concentration for every 2∼3 hrs during one day. The concentrations of acrolein observed were in the range of 69∼288 ng/m³.

Changes of water temperature in Lake Biwa and the atmospheric factors that can affect the water temperature were analyzed. The water temperatures of effluent from sewage plants were found to increase, but it did not affect the annual mean temperatures of the lake surface water. The change pattern of surface water temperatures in summer resembles the change pattern of the number of hot days with temperatures exceeding 25°C. On the other hand, the change pattern of the water temperatures in winter resembles the change pattern of the number of cold days with temperatures dropping below 0°C. These results show that the water temperatures of Lake Biwa conspicuously increased in the past 30 years, and it was caused mainly by increasing atmospheric temperatures. It is suggested that the increase in the annual mean temperature of the deep water is affected by the absence of a decrease in the water temperatures in winter, and the increase in the annual mean temperature of surface water is affected by the increase in the water temperatures in summer.