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  • 1
    Electronic Resource
    Electronic Resource
    Visible Diode Laser-Induced Fluorescence Detection in Liquid Chromatography after Precolumn Derivatization of Amines (1995)
    s.l. : American Chemical Society
    Analytical chemistry 67 (1995), S. 1742-1748 
    Details
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ac00106a015
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  • 2
    Electronic Resource
    Electronic Resource
    At-line SPE–GC–MS of micropollutants in water using the PrepStation (1999)
    Springer
    Fresenius' journal of analytical chemistry 364 (1999), S. 106-112 
    Details
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract An automated at-line SPE–GC–MS system for the determination of micropollutants in aqueous samples, which is based on the PrepStation and uses large-volume on-column injections, has been redesigned. A cartridge made from stainless steel and polychlorotrifluoroethylene and a 2-needle system was constructed which allow the determination of micropollutants at the low ng/L level without interferences from impurities extracted from the septa of the vials or the commercial cartridges. No time-consuming pre-cleaning of the cartridges or septa is required. The SPE sample extract (300 μL) is transferred from the sample preparation module to the autosampler of the GC–MS and 50 or 100 μL are injected. The analytical characteristics of the integrated procedure such as analyte recovery (typically 80–105%) and repeatability (RSDs, 2–9%), were satisfactory. Several micropollutants were detected in (unfiltered) river water at the 0.2–400 ng/L level using full-scan MS acquisition. The system proved to be robust during the analysis of more than 100 tap and river water samples.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002160051308
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    On-line chromatographic pretreatment of samples with varying salt concentrations for capillary electrophoresis (1997)
    Springer
    Chromatographia 44 (1997), S. 581-588 
    Details
    ISSN: 1612-1112
    Keywords: Capillary electrophoresis ; On-line LC-CE ; Sample pretreatment ; Matrix effects ; Benzoic acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Various methods are currently under investigation to improve concentration detection limits in capillary electrophoresis (CE). Stacking and isotachophoresis coupled in-line with free-solution electrophoresis are the techniques most frequently used. Samples containing a high and/or varying salt concentration, such as urine and serum, are difficult to handle: usually a significant loss in electrophoretic efficiency is observed compared with samples possessing a low electric conductivity. In the present paper an alternative approach is developed, i.e. a liquid chromatographic (LC)-type of sample pretreatment is coupled on-line with CE. To demonstrate the feasibility of this approach, the separation of three model compounds (benzoates) in water containing up to 400 mM of sodium chloride is studied using a 50 mM borate CE buffer of pH 9.5. The direct injection of samples with high salt concentrations in CE results in peak splitting and/or serious band broadening. These problems are not encountered when using the present LC-CE system. In addition, the detection limits are hardly influenced by the salt concentration of the sample; this underlines the robustness of the system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02466659
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  • 4
    Electronic Resource
    Electronic Resource
    On-line coupling of solid-phase extraction and gas chromatography with atomic emission detection for analysis of trace pollutants in aqueous samples (1995)
    Springer
    Chromatographia 40 (1995), S. 119-124 
    Details
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Atomic emission detection ; Aqueous samples ; Solid-phase extraction ; Organophosphorus pesticides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary An on-line, solid-phase extraction gas chromatography atomic-emission detection (SPE-GC-AED) system has been set up using an on-column interface to transfer 100 μl of desorbing solvent to the GC part of the system. Analytical characteristics such as recovery, precision and linearity of calibration plots were comparable with those of the off-line combination of SPE-GC-AED using organophosphorus pesticides as test compounds. The fully on-line set-up causes a marked improvement in detection because of the quantitative transfer of the analytes from the SPE module to the GC: detection limits are as low as 5–20 ng l−1 for the analysis of 10 ml raw and spiked surface water samples using the phosphorus channel. Detection levels can be further enhanced by processing up to 100 ml samples. The integrated analytical system is robust. The potential of the on-line set up has been demonstrated for the analysis of surface water and waste water.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02272157
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  • 5
    Electronic Resource
    Electronic Resource
    On-line sample treatment—capillary gas chromatography (1998)
    Springer
    Chromatographia 47 (1998), S. 313-345 
    Details
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Sample pretreatment ; Coupling on-line to capillary GC ; Robotization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Sample pretreatment is often the bottleneck of a tracelevel analytical procedure. In order to increase performance, increasing attention is therefore being devoted to combining sample pretreatment on-line with the separation technique that has to be used. In the present review, a variety of procedures in use today for sample treatment coupled on-line to capillary gas chromatography (GC) is briefly discussed. Special attention is devoted to coupled-column techniques such as SPE-GC and LC-GC (SPE, solid-phase extraction; LC, column liquid chromatography) which are topics of much current interest, also because of their frequent use in so-called hyphenated systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02466538
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  • 6
    Electronic Resource
    Electronic Resource
    Single short-column liquid chromatography with atmospheric pressure chemical lonization-(tandem) mass spectrometric detection for trace environmental analysis (1996)
    Springer
    Chromatographia 42 (1996), S. 506-514 
    Details
    ISSN: 1612-1112
    Keywords: Single short-column LC ; On-column sample enrichment ; Atmospheric pressure chemical ionization ; LC-tandem MS ; Environmental analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Single short, i.e. ca 2-cm long, high-pressure-packed columns coupled with mass spectrometric (MS) or tandem MS detection enable rapid trace-level determination and identification of environmental pollutants in water samples. In this study an atmospheric pressure chemical ionization (APCI) interface has been used and the overall set-up was tested with a mixture of seventeen pesticides, including organophosphates, carbamates, phenylureas and triazines. For the majority of the test analytes, the most prominent peaks in the positive-ion APCI-MS spectra resulted from protonated molecules. For fifteen out of the seventeen pesticides short-column liquid chromatography (LC)-APCI-MS of water samples as small as 15 mL resulted in detection limits between 0.03 and 5 μg L−1 in full-scan mode and between 2 and 750 ng L−1 by selected ion monitoring (SIM), both recorded in the positive-ion mode. Production spectra from protonated molecules of the majority of the selected pesticides present at a level of 0.1 μg L−1 in tap water are successfully identified from a search against a pesticide MS-MS library compiled in-house. This short-column LC-APCI-MS(-MS) approach has, on the basis of full-scan positive-ion data and their product-ion spectra, also been used to confirm the identity of target compounds and to identify unknown organic micropollutants in environmental waters.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02290284
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  • 7
    Electronic Resource
    Electronic Resource
    On-line solid-phase extraction-gas chromatography-ion trap tandem mass spectrometric detection for the nanogram per liter analysis of trace pollutants in aqueous samples (1997)
    Springer
    Chromatographia 44 (1997), S. 372-380 
    Details
    ISSN: 1612-1112
    Keywords: Solid-phase extraction ; Gas chromatography ; Ion trap tandem mass spectrometry ; Water samples ; Environmental analysis ; Pesticides ; Bromide ; Nitrite
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary On-line solid-phase extraction-gas chromatographyion-trap tandem mass spectrometry (SPE-GC-MS/MS) has been used for the trace-level determination of polar and apolar pesticides. The SPE-GC interface, an Autoloop 2000, was operated at an injection temperature of 90°C which permitted the determination of thermolabile pesticides such as carbofuran and carbaryl. Rectilinear calibration curves were obtained for the analytes tested over a range of 0.1–500 ng L−1, using a sample volume of 10–100 mL for enrichment on an SPE cartridge packed with styrene-divinylbenzene copolymer. The detection limits for the pesticides were in the 0.01–4 ng L−1 range. For a number of pesticides acceptable tandem mass spectra were obtained at levels as low as 0.1 ng L−1 level in real-life water samples. As a demonstration of the applicability of this technique for inorganic anions, bromide and nitrite were converted into 4-bromoacetanilide and 2-phenylphenol, respectively. The reaction products were pooled and subjected to simultaneous analysis by the present method using full-scan mass spectrometric detection. The detection limits were 0.3 and 2 ng L−1, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02466313
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  • 8
    Electronic Resource
    Electronic Resource
    Reversed-phase liquid chromatography coupled on-line with capillary gas chromatography use of an anion-exchange membrane to remove an ion-pair reagent from the eluent (1995)
    Springer
    Chromatographia 40 (1995), S. 267-271 
    Details
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Column liquid chromatography ; On-line coupling ; Ion-exchange membrane ; Ion-pair reagent
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary In order to enable the coupling of reversed-phase liquid chromatography (RPLC) with capillary gas chromatography (GC), the performance of an anion-exchange micromembrane device has been studied to remove the ion-pair reagent methanesulphonic acid from an acetonitrile/water LC eluent. The regenerant in the membrane was tetrabutylammonium hydroxide dissolved in acetonitrile/water, which effects an anion-exchange of methanesulphonate ions for regenerant hydroxide ions. The efficiency of the exchange process was found to be 99.9%. This enabled the direct introduction of the LC eluent, free of ions and with the proper acetonitrile/water ratio, into the GC. The applicability of the on-line LC-micromembrane-GC system has been illustrated for the potential drug eltoprazine, which is quantitatively recovered with a coefficient of variation for standard solutions of 3% at the 150 μg/ml analyte level.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02290356
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  • 9
    Electronic Resource
    Electronic Resource
    Determination of Organotin Compounds in the Foodweb of a Shallow Freshwater Lake in The Netherlands (1996)
    Springer
    Archives of environmental contamination and toxicology 31 (1996), S. 319-328 
    Details
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract. An extensive study on the presence of nine organotin compounds (OTs) in a freshwater foodweb was made, using newly developed analytical procedures in order to obtain insight in accumulation and degradation processes. Tributyltin (TBT), Triphenyltin (TPT) and their degradation products were detected. Zebra mussels, eel, roach, bream, pike, perch, and pike perch and cormorant showed high OT body concentrations. At the lower trophic levels, phenyltin concentrations were higher in benthic species while butyltin concentrations were higher in pelagic species. This indicates that TBT is passed on primarily via the water, while TPT is passed on to a larger extent via the sediment. At the higher trophic levels, net bioaccumulation of TPT was greater than that of TBT, resulting in relatively higher TPT concentrations. High concentrations of biodegradation products of TBT, but not of TPT, were found in the livers of fish and birds, which indicates that TBT is more easily metabolized than TPT. A comparison with literature data of fish lethal body concentrations revealed that fish in the field may be endangered. With birds, the highest concentrations of OTs were present in liver and kidney and not in subcutaneous fat, which confirms that OTs accumulate via different mechanisms than traditional lipophilic compounds. As a whole the OT concentrations found in the foodweb may be considered to be quite alarming.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002449900115
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    Paper (German National Licenses)
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  • 10
    Electronic Resource
    Electronic Resource
    Determination of organotin compounds in the foodweb of a shallow freshwater lake in The Netherlands (1996)
    Springer
    Archives of environmental contamination and toxicology 31 (1996), S. 319-328 
    Details
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract An extensive study on the presence of nine organotin compounds (OTs) in a freshwater foodweb was made, using newly developed analytical procedures in order to obtain insight in accumulation and degradation processes. Tributyltin (TBT), Triphenyltin (TPT) and their degradation products were detected. Zebra mussels, eel, roach, bream, pike, perch, and pike perch and cormorant showed high OT body concentrations. At the lower trophic levels, phenyltin concentrations were higher in benthic species while butyltin concentrations were higher in pelagic species. This indicates that TBT is passed on primarily via the water, while TPT is passed on to a larger extent via the sediment. At the higher trophic levels, net bioaccumulation of TPT was greater than that of TBT, resulting in relatively higher TPT concentrations. High concentrations of biodegradation products of TBT, but not of TPT, were found in the livers of fish and birds, which indicates that TBT is more easily metabolized than TPT. A comparison with literature data of fish lethal body concentrations revealed that fish in the field may be endangered. With birds, the highest concentrations of OTs were present in liver and kidney and not in subcutaneous fat, which confirms that OTs accumulate via different mechanisms than traditional lipophilic compounds. As a whole the OT concentrations found in the foodweb may be considered to be quite alarming.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00212670
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    Paper (German National Licenses)
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