Detection Of Contaminants In Water Research Articles

Laser Induced Fluorescence Spectroscopy of Phytoplankton and Chemicals with Regard to an in situ Detection in Waters

Summary In order to be able to detect chemicals in waters the suitability of laser-induced fluorescence spectroscopywas evaluated as a tool for the in situ detection of water contaminants and possible interactions with phytoplankton and yellow-substances. A frequency doubled dye laser was used as an excitation light-source. The substances were dissolved inwater and excited in the range from 265 nm to 400 nm. The fluorescence signal was recorded in the range from 310 nm to 750 nm. The absorption-, fluorescence- and excitation-spectra of each contaminant were measured in distilled water, artificial seawater and natural seawater. Computer-simulations were applied to analyse the spectra of pollutant mixtures. Firstly we investigated as to whether there are fluorescence-spectroscopically recognizable intermediatestages of phytoplankton and their breakdown-products (yellow-substances). Modifications of the fluorescence spectra during the ageing and dying of phytoplankton could be shown. Phytoplankton which is subject to sudden death display spectra differing from those of slowly dying organisms, e.g. the shift of the chlorophyll maximum to shorter wavelengths was measured. The spectra of mixtures containing phytoplankton and chemicals show differenes which depend on the characteristics of the chemicals concerned. PAHs and lead-acetate were used.

Application of pulsed laser photoacoustic sensors in monitoring oil contamination in water

Abstract A pulsed laser photoacoustic measurement technique, utilising laser diode sources, has been developed for the detection of oil contamination in water. The measurement of oil-contaminated water samples of oil concentration ranging from 0 to 900 mg 1−1 is presented. Also reported are results from a theoretical modelling, which includes several experimental factors important to the photoacoustic sensor design for this type of application.

Hazardous waste storage, disposal, remediation, and closure

Hazardous waste storage, disposal, remediation, and closure

Application of passive dosimetry to the detection of trace organic contaminants in water

La dosimetrie passive habituellement utilisee pour controler les polluants de l'air, est ici utilisee pour l'analyse du p-xylene et de l'atrazine dans les eaux naturelles

Feasibility studies for the detection of organic surface and subsurface water contaminants by surface-enhanced Raman spectroscopy on silver electrodes.

Fundamental components of various families of organic contaminants that are found in surface and subsurface waters have been investigated by surface-enhanced Raman spectroscopy (SERS). The SERS substrate was a silver electrode maintained at various electrode potentials. The limit of detection for pyridine was calculated to be 8.5 pg. Variation of the electrode potential and excitation wavelength was used to qualitatively determine a two-component mixture of contaminants. The in situ type of conditions of low ionic strengths and humic materials was found not to inhibit the SERS effect on the silver electrode.

β-Naphthol as a Chromophore and Fluorophore Forming Reagent in the HPLC Determination of Alkyl Halides

Abstract A suitable chromophore- and fluorophore- forming reagent for the detection of alkyl halide water contaminants is β-naphtol. The ether derivatives are separated from each other and excess β-naphthol reagent by reverse, phase HPLC and are detected by ultraviolet absorption or fluorescence. A method for the determination of alkyl halides is presented. The method is applicable to concentration levels in the ppm range for UV detection and in the ppb concentration range using fluorescence detection.