The University of Southampton
University of Southampton Institutional Repository

Development of novel solid phase extraction materials for pesticide residue analysis

Development of novel solid phase extraction materials for pesticide residue analysis
Development of novel solid phase extraction materials for pesticide residue analysis

β-Cyclodextrin (βCD) has been immobilized on silica and Amberlite XAD resin bases and evaluated as selective material for use in solid phase extraction (SPE). This work focuses on the synthesis, characterization and applications of the SPE materials in the determination of pesticide residues.

A number of synthetic methods were employed for bonding βCD to silica and XAD-4 resin. βCD, methylated βCD and the mixed functionality of diol and βCD phases were prepared on a silica base using (3-isocyanatoproply)triethyoxysilane as a linker. βCD was also immobilized by adsorption onto Amberlite XAD-4 resin or by chemical linking onto silica-modified XAD-4.

The loadings of βCD on the modified silicas and XAD resins were qualitatively and quantitatively determined. Molish's test and a diphenylamine-aniline test confirmed the presence of βCD bonded on the solid phases. The βCD contents were colorimetrically determined using a newly developed phenol-sulphuric acid method. Silicas modified with βCD and the mixed functionality Diol-βCD showed little difference between their βCD loadings (17.4μmol and 16.7μmol βCD/g, respectively). Adsorption of βCD onto XAD resulted in material having a lower loading of βCD than the materials synthesised on a silica base. Infrared and Raman spectroscopy showed the presence of βCD on the silica surfaces. Elemental (CHN), gravimetric and thermogravimetric (TGA) analyses were together used to demonstrate the presence of organic material on the silica surface. The βCD loadings calculated from TGA and CHN data were in agreement with data obtained by the phenol-sulphuric acid colorimetric method. The ability of βCD to form inclusion complexes with a number of pesticides was assessed by TLC (thin layer chromatography), UV (ultraviolet spectrophotometry)., TGA and DSC (differential scanning calorimetry). TLC showed that for many pesticides the formation of such complexes is either kinetically very slow or that it may not occur. The addition of βCD to dichlobenil and triallate enhanced their UV absorption spectra, suggesting possible complex formation. The TGA and DSC characteristics of the atrazine-βCD "complex" were assigned to weak associations between βCD and atrazine rather than the presence of a true inclusion complex.

University of Southampton
Al-Saad, Jalal Abdulla
Al-Saad, Jalal Abdulla

Al-Saad, Jalal Abdulla (1998) Development of novel solid phase extraction materials for pesticide residue analysis. University of Southampton, Doctoral Thesis.

Record type: Thesis (Doctoral)

Abstract

β-Cyclodextrin (βCD) has been immobilized on silica and Amberlite XAD resin bases and evaluated as selective material for use in solid phase extraction (SPE). This work focuses on the synthesis, characterization and applications of the SPE materials in the determination of pesticide residues.

A number of synthetic methods were employed for bonding βCD to silica and XAD-4 resin. βCD, methylated βCD and the mixed functionality of diol and βCD phases were prepared on a silica base using (3-isocyanatoproply)triethyoxysilane as a linker. βCD was also immobilized by adsorption onto Amberlite XAD-4 resin or by chemical linking onto silica-modified XAD-4.

The loadings of βCD on the modified silicas and XAD resins were qualitatively and quantitatively determined. Molish's test and a diphenylamine-aniline test confirmed the presence of βCD bonded on the solid phases. The βCD contents were colorimetrically determined using a newly developed phenol-sulphuric acid method. Silicas modified with βCD and the mixed functionality Diol-βCD showed little difference between their βCD loadings (17.4μmol and 16.7μmol βCD/g, respectively). Adsorption of βCD onto XAD resulted in material having a lower loading of βCD than the materials synthesised on a silica base. Infrared and Raman spectroscopy showed the presence of βCD on the silica surfaces. Elemental (CHN), gravimetric and thermogravimetric (TGA) analyses were together used to demonstrate the presence of organic material on the silica surface. The βCD loadings calculated from TGA and CHN data were in agreement with data obtained by the phenol-sulphuric acid colorimetric method. The ability of βCD to form inclusion complexes with a number of pesticides was assessed by TLC (thin layer chromatography), UV (ultraviolet spectrophotometry)., TGA and DSC (differential scanning calorimetry). TLC showed that for many pesticides the formation of such complexes is either kinetically very slow or that it may not occur. The addition of βCD to dichlobenil and triallate enhanced their UV absorption spectra, suggesting possible complex formation. The TGA and DSC characteristics of the atrazine-βCD "complex" were assigned to weak associations between βCD and atrazine rather than the presence of a true inclusion complex.

This record has no associated files available for download.

More information

Published date: 1998

Identifiers

Local EPrints ID: 463416
URI: http://eprints.soton.ac.uk/id/eprint/463416
PURE UUID: e8afeb7d-8751-4713-b49a-42cb6674f4f8

Catalogue record

Date deposited: 04 Jul 2022 20:51
Last modified: 04 Jul 2022 20:51

Export record

Contributors

Author: Jalal Abdulla Al-Saad

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×