Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Urea herbicides ; Catalytic hydrolysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A method is described for the rapid catalytic hydrolysis of phenylurea herbicides on silica gel at elevated temperatures. After derivatisation of the anilines produced with heptafluorobutyric acid anhydride final analysis is done on a gas chromatograph equipped with an electroncapture detector. Detection limits are in the 1–5 picogram range. The method has successfully been applied to residue analysis of water samples at the 1 ppb level. The determination of free anilines present in water samples and the potential of various techniques to be used to discriminate between free anilines and parent herbicides are also discussed.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Immunoaffinity precolomn ; Oestrogens ; Bioanalysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary An automated liquid chromatographic system is described using immunoaffinity precolumns for sample pretreatment. The system consists of a column-switching unit allowing preconcentration from a large volume of sample (e.g. 15 ml of urine) onto an immunoaffinity precolumn (containing polyclonal antibodies immobilized on Sepharose). After sorption, the analytes are desorbed by a mixture of two cross-reacting solutes, followed by reconcentration on a C-18-bonded silica precolumn, and then separation on a C-18-bonded silica analytical column. Using oestrogen steroids as model compounds and UV absorbance detection, the minimum detectable concentration is ca. 200 ng/l with a repeatability of 6–8%. The total analysis time is 45 min which allows the unattended analysis of 30 samples per day. The features of the sample pretreatment method, especially of the immunoselective desorption, are evaluated and the general applicability of the system is discussed.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1612-1112
    Keywords: Liquid chromatography ; Photochemical reaction detection ; Chemical post-column reduction ; Fluorimetric detection ; Air segmented flow systems ; Non-aqueous reversed-phase chromatography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A new photochemical reaction method for the on-line fluorimetric detection of natural vitamin K homologs was developed. In addition to its high sensitivity, the method features an interesting selectivity for the determination of these compounds in a complex matrix such as human serum. The formation of different photolysis products as a function of reaction conditions, and the optimalisation of a segmented flow reaction system will be discussed. The results indicate that the method is 4 times more sensitive than UV detection, and at least as selective as fluorescence detection after post-column chemical reduction.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1612-1112
    Keywords: Narrow-bore column liquid chromatography ; Post-column derivatization ; Solid-phase reactors ; Catalytic hydrolysis ; On-line trace enrichment ; Immobilized enzyme
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The use of solid-phase reactors for post-column derivatization in narrow-bore HPLC (1.0mm i.d. analytical columns) is evaluated. Two systems are described, viz. for the determination of N-methylcarbamate pesticides and for that of urea and ammonia. The solid-phase reactor is packed with a strong anion exchange resin and urease immobilized on silica, respectively, to effect the catalytic hydrolysis of the solutes eluting from the analytical column. In both systems, the hydrolysis product is reacted with o-phthalaldehyde followed by fluorescence monitoring. Analytical data are presented and band broadening from various parts of the reaction detector system is discussed. An on-line trace enrichment procedure via a micro precolumn is descried for the trace level determination of N-methylcaramates in surface water samples.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...