ISSN:0323-4320    

DOI:10.1002/aheh.19950230102

出版商:WILEY‐VCH Verlag GmbH    

年代:1995

数据来源: WILEY

摘要:

AbstractAn automated HPLC method is presented which combines on‐line ion‐pair extraction on small exchangeable RP‐C18 precolumns (RP‐IPE) with ion‐pair chromatography (RP‐IPC). Weakly acidic herbicides — carboxylic acids, phenols, and the N‐H acidic bentazone — and strong acids, e.g. aromatic sulfonic acids, can be determined simultaneously. Performance data are given. The tetrabutylammonium ion pairs of all investigated compounds are readily transferred from the RP‐C18 precolumn to the analytical column by a phosphate buffer/methanol gradient. This is also true for the chlorinated phenoxy acids which, in earlier off‐line extraction experiments, could not be desorbed from the RP‐C18 material by the lower polar acetone. The RP‐IPC is carried out at neutral pH where weakly acidic compounds appear in their stronger UV absorbing dissociated form. Compared to conventional reversed phase chromatography using an acidified eluent, the sensitivity of UV detection is markedly enhanced, especially for the phenol herbicides and bentazone. In addition, phenols can be detected more selectively because they show a second intense absorption band in the wavelength range between 280 nm and 290 nm, where there are only little interferences with the matrix. Due to miniaturization and automation, the online combination IPE/IPC allows a large sample throughput at a lower consumption of solid phase material and organic solvents. Time consuming manual steps are totally missing. The IPE/IPC technique is well suited as a screening method for fate studies of polar micropollutants, e. g. for monitoring the efficiency of different water treatment technologies. An example for balancing an activated c

ISSN:0323-4320    

DOI:10.1002/aheh.19950230103

出版商:WILEY‐VCH Verlag GmbH    

年代:1995

数据来源: WILEY

摘要:

AbstractMethods for the determination of three compound classes, i. e. diaminotoluenes, nitrophenols, and chloroaromatics in groundwater of a former ammunition plant are reported. Diaminotoluenes were extracted by discontinuous liquid/liquid‐, nitrophenols by continuous liquid/liquid‐extraction using dichloromethane, and chloroaromatics by solid‐phase extraction. These compound classes may be analyzed by gas chromatography (GC) or gas chromatography coupled to mass spectrometry (GC/MS) without derivatization or after derivatization with N‐methyl‐bis(trifluoroacetamide) (MBTFA) or heptafluorobutyric anhydride (HFBA) in the case of diaminotoluenes and HFBA or acetic anhydride in the case of nitrophenols. An atomic emission detector (AED) coupled to a gas chromatograph may be employed for the analysis of chloroaromatics. High selectivity can be achieved using the characteristic wavelengths of chlorine. A variety of these compounds were identified and quantified in a groundwater sample from the former ammunition plant Elsnig (Saxony, Germany). Concentrations were in the lower ppb range. Thus, dichlorobenzenes which may have been used as substituents at the end of World War II could be identified in groundwater samples at

ISSN:0323-4320    

DOI:10.1002/aheh.19950230104

出版商:WILEY‐VCH Verlag GmbH    

年代:1995

数据来源: WILEY

摘要:

AbstractKlärschlämme aller westdeutschen Bundesländer aus den Jahren 1987 bis 1989 wurden auf zwei in der Klärschlammverordnung von 1992 nicht aufgeführte Gruppen von organischen Schadstoffen untersucht: die 4‐Nonylphenole und die Chlorphenole. Die dazu benutzten Analysenmethoden werden dargestellt, außerdem die Analysenergebnisse. In fast allen der 149 untersuchten Proben fand man Nonylphenole, im Durchschnitt zu 128.2 mg/kg Trockensubstanz (TS). Bei den Chlorphenolen kam dem Pentachlorphenol hinsichtlich Häufigkeit und Höhe positiver Befunde die größte Bedeutung zu: Bei 85 untersuchten Proben betrug z. B. der Mittelwert 59.5 μg/kg TS. Die Ergebnisse werden in Perzentilform angegeben. Diese sich auf Klärschlämme der Vergangenheit beziehenden Daten sollen eine Richtschnur zur Beurteilung heutiger und künftiger Analysenbefunde darstellen; die Untersuchungen wer

ISSN:0323-4320    

DOI:10.1002/aheh.19950230105

出版商:WILEY‐VCH Verlag GmbH    

年代:1995

数据来源: WILEY

摘要:

AbstractA method for the trace‐level determination of bromate in raw and drinking water is reported. The procedure combines the quantitation of bromate by ion chromatography with a concentration step which in the main is composed of an unselective enrichment of all water constituents by means of a rotatory evaporator and a selective removal of the chloride ions. With this method, the reliable determination of bromate in raw and drinking waters is possible down to concentrations of at least 1 μg/L.The method is used for systematic examinations in several German waterworks which use ozone for the preparation of drinking water. The resulting data clearly prove that during the ozonation of bromide‐containing waters, bromate is produced, whereby the concentration of bromate in the ozonated raw water can exceed 10 μg/L. Some correlations between the amount of bromate and the respective conditions of ozonation are pointe

ISSN:0323-4320    

DOI:10.1002/aheh.19950230106

出版商:WILEY‐VCH Verlag GmbH    

年代:1995

数据来源: WILEY

摘要:

AbstractHumic substances isolated from water, sediment, and soil were characterized by applying elemental analysis, spectroscopic analysis, and gelchromatographic molecular size distribution. In addition, the amounts and pattern of enzymatically released amino acids were determined.Depending on the origin of the humic substances, the percentage of released amino acid nitrogen related to the total nitrogen was in the range of 0.4 to 26.7%. The samples particularly differed in the content of leucine und tyrosine. The total amount of released amino acids was compared with the results obtained from the other characterization methods. This approach indicated that humic substances with a high content of hydrolysable amino acids had high N/C and O/C ratios and low molecular sizes. Beside this, the absorption of these substances in the UV and visible wavelength range was quite low, while the measured ratios of SAK(254)/SAK(436) showed high values.This work leads to the conclusion that the extent of enzymatically releasable amino acids is not only dependant on the nitrogen content of humic substances. Other physical and chemical properties have to be considered for the understanding of the results obtained by the described biochemical characterization method.

ISSN:0323-4320    

DOI:10.1002/aheh.19950230107

出版商:WILEY‐VCH Verlag GmbH    

年代:1995

数据来源: WILEY

ISSN:0323-4320    

DOI:10.1002/aheh.19950230108

出版商:WILEY‐VCH Verlag GmbH    

年代:1995

数据来源: WILEY

ISSN:0323-4320    

DOI:10.1002/aheh.19950230109

出版商:WILEY‐VCH Verlag GmbH    

年代:1995

数据来源: WILEY

ISSN:0323-4320    

DOI:10.1002/aheh.19950230111

出版商:WILEY‐VCH Verlag GmbH    

年代:1995

数据来源: WILEY

ISSN:0323-4320    

DOI:10.1002/aheh.19950230112

出版商:WILEY‐VCH Verlag GmbH    

年代:1995

数据来源: WILEY