Determination of N,N-dimethyldodecylamine and N,N-dimethyloctadecylamine in river and sea water using liquid chromatography tandem mass spectrometry.

We developed a selective method for determining N,N-dimethyldodecylamine (DMDA) and N,N-dimethyloctadecylamine (DMOA) concentrations in river and sea water samples using liquid chromatography/tandem mass spectrometry (LC/MS/MS). DMDA and DMOA are suspected to be toxic, and DMDA is categorized as a "Class I Designated Chemical Substance" under the "Act on Confirmation, etc. of Release Amounts of Specific Chemical Substances in the Environment and Promotion of Improvements to the Management Thereof" in Japan. The analytes are extracted from a water sample using solid phase extraction and the extract is evaporated and dissolved in 1 mL methanol for LC/MS/MS analysis. We analyzed DMDA and DMOA in real water samples and found that the analyte peaks were resolved effectively. The method detection limits for DMDA and DMOA were 4.7 and 0.80 ng/L, respectively.

Determination of 4,4'-, 3,4'-, and 2,2'-diaminodiphenylethers in sediment samples from the sea using liquid chromatography-tandem mass spectrometry.

A selective method has been developed for determining the concentration of 4,4'-, 3,4'-, and 2,2'-diaminodiphenylethers in sediment samples from the sea, using liquid chromatography/tandem mass spectrometry (LC/MS/MS). 4,4'-diaminodiphenylether is a suspected toxic compound, and categorized as "Class I Designated Chemical Substance" in Japan. We have investigated the levels of 4,4'-diaminodiphenylether in sediments to evaluate long-term water pollution. The methods detection limits for the 4,4'-, 3,4'-, and 2,2'-diaminodiphenylethers were 2.0, 1.7, and 4.8 ng/g-dry, respectively.

Selective determination of 2,4-xylenol by gas chromatography/supersonic jet/resonance-enhanced multiphoton ionization/time-of-flight mass spectrometry.

Gas chromatography/supersonic jet/resonance-enhanced multiphoton ionization/time-of-flight mass spectrometry (GC/SSJ/REMPI/TOF-MS) was employed for isomer-selective determination of 2,4-xylenol in river and seawater samples. The sample containing 2,4-xylenol was measured using argon, rather than helium, as the GC carrier gas to cool the analyte molecule sufficiently. The instrumental detection limit (IDL) achieved at a flow rate of 1 mLmin(-1) was 14 pg. Although this value was comparable to the value (ca. 10 pg) obtained by gas chromatography/electron impact/quadrupole mass spectrometry (GC/EI/QMS). When the flow rate was increased to 8 mLmin(-1), interference from the 2,5-xylenol isomer was completely suppressed. The IDL was degraded to 83 or 160 pg at a flow rate of 5 or 8 mLmin(-1), respectively. The recovery of 2,4-xylenol from the river and the seawater samples was 85 and 93%, respectively. The time for analysis was only 10 min per one sample in GC/SSJ/REMPI/TOF-MS. These results suggest that GC/SSJ/REMPI/TOF-MS is useful for the selective measurement of 2,4-xylenol, which has been designated a Class I chemical substance in the Pollutant Release and Transfer Register (PRTR).

Trace analysis of polycyclic aromatic hydrocarbons using gas chromatography-mass spectrometry based on nanosecond multiphoton ionization.

Gas chromatography/resonance-enhanced multiphoton ionization/time-of-flight mass spectrometry (GC/REMPI-TOFMS) using an ultraviolet nanosecond laser was employed in the trace analysis of polycyclic aromatic hydrocarbons (PAHs). A standard sample that contained 16 PAHs on the priority list of the Environmental Protection Agency of the United States of America (U.S. EPA) was measured. A sample of river water that had been pretreated by means of solid-phase extraction was analyzed by GC/MS based on electron impact ionization (EI) and REMPI to evaluate the performance of the analytical instrument. The results suggested that REMPI is superior to EI for soft ionization, and suppresses the background signal due to aliphatic hydrocarbons. Thus, GC/REMPI-TOFMS is a more reliable method for the determination of PAHs present in the environment.

Enhancement of molecular ions in mass spectrometry using an ultrashort optical pulse in multiphoton ionization.

The spectral domain of an ultraviolet femtosecond laser was expanded by stimulated Raman scattering/four-wave Raman mixing, and the resulting laser pulse was compressed using a pair of gratings. The pulse width was then measured using an autocorrelator comprised of a Michelson interferometer equipped with a multiphoton ionization/mass spectrometer which was used as a two-photon detector. A gas chromatograph/mass spectrometer was employed to analyze triacetone triperoxide (TATP), and the molecular ion induced by multiphoton ionization was substantially enhanced by decreasing the laser pulse width.

Selective ionization of 2,4-xylenol in mass spectrometry using a tunable laser and supersonic jet technique.

A supersonic jet/resonance-enhanced multiphoton ionization/time-of-flight mass spectrum (SSJ/REMPI/TOF-MS) was measured for xylenols and ethylphenols. Sharp and intense peaks were observed in the REMPI spectrum of 2,4-xylenol, and the wavelength of the peak tentatively assigned to the 0-0 transition was the longest among xylenols and ethylphenols. These results suggest that 2,4-xylenol, designated as a Class II chemical substance in the Pollutant Release and Transfer Register (PRTR), can be measured sensitively and selectively even when numerous isomers are present in the sample.

Simple and sensitive determination of 2,4-xylenol in surface water samples from river and sea by gas chromatography-mass spectrometry.

A simple and selective method was developed for determination of the concentration of 2,4-xylenol in river and sea water samples using gas chromatography/mass spectrometry (GC/MS). Trace amounts of 2,4-xylenol were collected in a Oasis HLB Plus cartridge, eluted with acetonitrile. The method detection limit of 2,4-xylenol was 1.4 ng/L. The trace peaks of 2,4-xylenol were found in water samples from the river and the sea, and the concentrations were all less than 1.4 ng/L. The nine peaks of the 2,3-, 2,4-, 2,5-, 2,6-, 3,4-, 3,5-xylenol, and o-, m-, p-ethyl phenol that gave the same m/z ratio were separated efficiently.

Determination of hexaconazole in surface water samples from river and the sea by liquid chromatography-electrospray tandem mass spectrometry.

A simple and selective method was developed for determining the concentration of hexaconazole in river and sea water samples by using liquid chromatography/tandem mass spectrometry with an electrospray ionization interface in the positive ion mode and selective reaction monitoring mode. Trace amounts of hexaconazole were collected in a Sep-Pak Plus tC18 cartridge that was eluted with methanol. The detection limit for hexaconazole was 6 ng/l. The recovery of a standard aqueous solution containing 1 microg/l was 96%. The recovery of hexaconazole in the river and sea water samples was 95% and 90%, respectively. Hexaconazole was not detected in the sea water samples. Trace peaks of hexaconazole were found in the river water samples, the concentration being less than 6 ng/l in all cases. The biological degradation of hexaconazole was tested by using river water. No degradation of hexaconazole was apparent in river water incubated at 20 degrees C for 3 weeks.

Mutagenic activity in roadside soils.

Mutagenicity of soils sampled at median strips, roadsides and a park neighboring arterial roads in Kurume City was determined by Ames test. Organic extracts of soils were mutagenic in strains TA98, TA100, YG1041 and YG1042 with and without S9mix. No sample showed mutagenic responses in strains YG3003 or YG7108. Extracts from soils of median strips and beside intersections showed higher mutagenicity and concentrations of PAHs and heavy metals than others, and mutagenic activity of soils correlated significantly with concentrations of PAHs and heavy metals. However, PAHs accounted for less than 12% of total mutagenicity in strains TA98 and TA100 of soil extracts. These extracts showed much higher mutagenicity in YG strains than in TA strains. The results indicate that these soils may be polluted with nitroarenes and aromatic amines.