摘要:

This paper describes the design, performance and operation of a home-made capillary dosage unit with in situ weight sensor. This continuous injection technique is developed to produce dynamic gas phase calibration mixtures of VOC's in a diluent gas at occupational hygiene levels. A new advance in the technique allows the calculation of the amounts of pollutants emitted into the carrier gas, directly from the gravimetric measurements.

ISSN:0306-7319    

DOI:10.1080/03067319208027031

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Air particulate samples were collected from the Black Sea atmosphere, using cellulose filters in the summer of 1988. Lead and nickel concentrations in aerosols collected at 10 m above sea level were determined by using electrothermal atomization atomic absorption spectrometry (ETA-AAS). Concentrations of Pb and Ni were high in the western part of the Black Sea, owing to strong influence of anthropogenic sources. Lead was highly enriched in the Black Sea aerosols due to the significant contribution of motor vehicle emissions, while Ni was moderately enriched. The Pb/Br ratio was higher than the corresponding ratio in fresh motor vehicle emissions, owing to evaporation of Br from particles. Atmospheric flux of Pb to the Black Sea was higher than riverain flux, while the opposite was observed for Ni.

ISSN:0306-7319    

DOI:10.1080/03067319208027032

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

A technique was developed using sparging and pre-concentration onto a Tenax trap at ambient temperature allowing field measurements to be made of reduced sulfur gases in Antarctic marine and glacial melt waters. Following thermal desorption, gases were determined by gas chromatography using a flame photometric detector. Detection limits in ng 1−1were: H2S 50, OCS 8, SO2160, CH3SH 6, CH3SCH320 and CS22. Storage of melt water samples for more than 24 hours resulted in concentration changes of the reduced sulfur gases present. While the Antarctic environment imposed limitations on the analytical method, an investigation of various pond and marine waters was undertaken.

ISSN:0306-7319    

DOI:10.1080/03067319208027033

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The portable simplified photometer, in which high-luminous light emitting diode (LED) was used as a lamp, was manufactured as an useful tool forin situenvironmental water analysis. This photometer is applicable to various spectrophotometric methods for the determination of chemical species exhibiting an absorption λmaxof the colored complex spectrum around 660 nm and/or 560 nm.

ISSN:0306-7319    

DOI:10.1080/03067319208027034

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Membrane extraction disks loaded with alkyl-bonded silica, copolymer or ion-exchange material have been tested for the on-line trace enrichment of polar pesticides from surface water. To this end, a new membrane extraction disk holder has been designed, which can be used in the forward flush and backflush mode. The basic compounds carbendazim, chloridazon, simazine and 4-chloroaniline were used as test compounds. They are preconcentrated from acidic solution using one or two membrane extraction disk holders in series (operated in the reversed-phase and ion-pair mode), and analysed by gradient liquid chromatography with polymer PLRP-S as the stationary phase and aqueous acetonitrile mixtures (pH 3) as the eluent. Data on the efficiency and repeatability of the on-line procedure are reported. Preconcentration of 30 ml of surface (river Rhine) water allows the UV detection of the four pollutants at the 0.1 μg 1−1level.

ISSN:0306-7319    

DOI:10.1080/03067319208027035

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Column liquid chromatography on a reversed-phase (C-18) analytical column using a linear acetonitrile-water gradient and diode-array detection is used in an on-line early-warning system of over 50 pesticides in surface water. It allows the separation of most compounds with detection limits of about 1–5 μg/1 after preconcentration of 30 ml of sample. Problems encountered for co-eluting pesticides with similar spectra and pesticides with weak ultraviolet absorption over 230 nm, are discussed. If the system is combined with on-line trace enrichment on a styrene-divinylbenzene copolymer (PLRP-S) precolumn, the overall resolution is only slightly affected, and the qualitative information obtained remains about the same. Chromatograms of spiked (2–10 μg/1) surface (river Rhine) water containing 54 test compounds are shown. Preliminary studies show the stability of several pesticides in water to be rather low. Some degradation products have been detected in 1-month-old methanolic and aqueous solutions.

ISSN:0306-7319    

DOI:10.1080/03067319208027036

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

This is a scanned image of the original Editorial Board page(s) for this issue.

ISSN:0306-7319    

DOI:10.1080/03067319208027030

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor