Pre- and Postcolumn Derivatization Chemistry in Conjunction with HPLC for Pharmaceutical Analysis

Danielson, Neil D.; Targove, Margaret A.; Miller, Blair E.

doi:10.1093/chromsci/26.8.362

Cited by 23 publications

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“…4) The optimal conditions are set with regard to pH in the reaction mixture, which significantly affects the competitive rates of the labeling reaction and the hydrolysis of sulfonyl chlorides. The reaction mixture was prepared by the addition of 1.0 ml of an acetone solution of tosyl chloride to a mixture of 1.0 ml of the aqueous sample solutions and 1.0 ml of a buffer solution.…”

Section: Resultsmentioning

confidence: 99%

“…On the other hand, many attempts at chromatographic determination of analytes coupled with the derivatization reaction have been made to overcome the problems of low detection and insufficient separation. 4) However, the derivatization techniques utilizing the solid phase and solid phase-dispersed reactions have only been discussed in terms of efficiency in the analytical procedure, that is, efficient conversion of the analytes to the derivatives, high recovery, and shortening of the analysis time. [5][6][7][8][9] In particular, trace analyses of biological samples have been developed coupled with on-column derivatization and micro solid-phase extraction techniques.…”

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confidence: 99%

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Tosylation of Endocrine-Disruptive Alkylphenolic Compounds in a Solid-Phase Reaction System Consisting of C18-Modified Silica Gel and Aqueous Buffer Solution

Uno

Okumura

2004

CHEMICAL & PHARMACEUTICAL BULLETIN

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Recently, much attention has been paid to synthetic organic reactions in aqueous media instead of in organic solvents such as silica gel-dispersal and polymer-dispersal aqueous systems from the point of view of environmental conservation. [1][2][3] The results suggest that the total synthetic process in aqueous systems is simple and the interface between the solid phase and the aqueous liquid provides specificity and diversity in the synthetic reactions. On the other hand, many attempts at chromatographic determination of analytes coupled with the derivatization reaction have been made to overcome the problems of low detection and insufficient separation. 4) However, the derivatization techniques utilizing the solid phase and solid phase-dispersed reactions have only been discussed in terms of efficiency in the analytical procedure, that is, efficient conversion of the analytes to the derivatives, high recovery, and shortening of the analysis time. [5][6][7][8][9] In particular, trace analyses of biological samples have been developed coupled with on-column derivatization and micro solid-phase extraction techniques. 6,7) However, environmental analyses still essentially require an enrichment step such as preconcentration and a derivatization step to achieve low detection limits prior to chromatographic separation. 10) The solid-phase aqueous reaction is a desirable method for environmental analyses from the point of view of environmental conservation as well as efficiency in the analytical procedure.The derivatization reagents characterized by an active sulfonyl chloride to the phenolic hydroxyl group such as tosyl chloride (4-methylbenzenesulfonyl chloride), dansyl chloride, and ferrocenesulfonyl chloride are entirely used for precolumn derivatization to overcome the disadvantage of the background response. Precolumn dansylation is applied to the HPLC analysis of endocrine-disruptive alkylphenolic compounds in environmental water. 10) The solid-phase reaction of the sulfonyl chlorides is important in improving the analytical methods. In this study, we have developed a direct tosylation method for alkylphenolic compounds preconcentrated in a C 18 -modified silica gel (ODS) cartridge used for their enrichment step using a heterogeneous system consisting of an aqueous medium and ODS instead of organic solvents, as a prototype of the solid-phase derivatization method of the phenols with sulfonyl chlorides. ExperimentalChemicals Tosyl chloride as a derivatization reagent was purchased from Nacalai Tesque and used as received without further purification. The samples used were alkylphenols [4-tert-butylphenol, 4-sec-butylphenol, 4-(1,1-dimethylpropyl)phenol, 4-(1,1,3,3-tetramethylbutyl)phenol, and 4-nonylphenol] which are recognized as estrogenic compounds. 10) They were of the best available grade from Nacalai Tesque and Tokyo Chemical Industry and were used as received. The ODS powder was purchased from Nacalai Tesque and was used in the solid-phase disperse system as a solidphase catalyst.Preparation of the Standa...

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Tosylation of Endocrine-Disruptive Alkylphenolic Compounds in a Solid-Phase Reaction System Consisting of C18-Modified Silica Gel and Aqueous Buffer Solution

Uno

Okumura

2004

CHEMICAL & PHARMACEUTICAL BULLETIN

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“…(74 -78) Although the other articles do not try to be comprehensive, Ahuja (77) gave a virtually complete review of the topic up to 1979. Danielson et al (78) published another fairly complete review covering the period 1979-1987, which is the basis for this part of the article. Again, a specific example and an overview for each major class of pharmaceutical compounds are given.…”

Section: High-performance Liquid Chromatographymentioning

confidence: 99%

Chemical Reagents and Derivatization Procedures in Drug Analysis

Danielson

Gallagher

Bao

2008

Encyclopedia of Analytical Chemistry

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This article describes both pre‐ and postcolumn derivatization chemistry used in conjunction with either chromatography or capillary electrophoresis (CE) to facilitate the determination of drugs. Generally, only prederivatization is used in gas chromatography (GC), principally to enhance the volatility, temperature stability, and/or detectability. The GC section considers derivatization of drugs by reagent class: alkylation, acylation, and silylation. The GC sample‐handling section describes an approach that combines the extraction and derivatization steps together. Both pre‐ and postcolumn derivatization are common approaches for high‐performance liquid chromatography (HPLC) and many of these methods have been adapted for CE. Derivatization for HPLC is often directed toward aliphatic amines, carboxylic acids, or alcohols that are difficult to detect at low levels by absorbance, luminescence, or electrochemical means. In addition, small hydrophilic molecules upon prederivatization are often converted into larger more hydrophobic compounds, making reversed‐phase HPLC easier or even feasible. The HPLC section considers derivatization of drugs based on the following types: alkaloids, amines, antibiotics, barbiturates, carbonyl compounds and carboxylic acids, catecholamines, hydroxy compounds, steroids, and sulfur compounds. For the GC and HPLC sections, tables are included, giving the structures of the more important derivatizing agents, the analytes, and the corresponding reaction products. A brief rationale for derivatization chemistry with CE concludes this article. For CE, derivatization is often done to improve detectability as the path length for absorbance detection is very short and fluorescence can be effective using laser‐based systems.

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“…Details on these and other innovative detection systems are presented in the review by Bruckner [60]. [61,62] of a sample is undertaken principally for two reasons. First, there is no detector for HPLC that has universally high sensitivity for all solutes; hence, the use of a suitable chemical transformation of the solute can greatly extend the sensitivity and versatility of a selective detector.…”

Section: Electrochemical Detectorsmentioning

confidence: 99%