A study of electrospun nanofibers and diatomaceous earth materials for the extraction of alkaloids, flavonoids and aromatic amines in various matrices

Mothibedi, Kediemetse (Kedimetse)

Title: A study of electrospun nanofibers and diatomaceous earth materials for the extraction of alkaloids, flavonoids and aromatic amines in various matrices
Title: Study of electrospun nanofibres and diatomaceous earth materials for the extraction of alkaloids, flavonoids and aromatic amines in various matrices
Creator: Mothibedi, Kediemetse (Kedimetse)
Subject: Nanofibers
Subject: Electrospinning
Subject: Sorbents
Subject: Extraction (Chemistry)
Subject: Alkaloids
Subject: Flavonoids
Subject: Amines
Subject: Matrices
Subject: Goldenseal
Subject: Ginkgo
Subject: Dyes and dyeing -- Chemistry
Date Issued: 2013
Date: 2013
Date: 2013-04-07
Type: Thesis
Type: Masters
Type: MSc
Identifier: vital:4288
Identifier: http://hdl.handle.net/10962/d1003052
Identifier: Nanofibers
Identifier: Electrospinning
Identifier: Sorbents
Identifier: Extraction (Chemistry)
Identifier: Alkaloids
Identifier: Flavonoids
Identifier: Amines
Identifier: Matrices
Identifier: Goldenseal
Identifier: Ginkgo
Identifier: Dyes and dyeing -- Chemistry
Description: The thesis explored the use of different sorbent materials in solid phase extraction method development. The methods included the use of the polymeric Agilent Bond Elut Plexa solid phase extraction and electrospun polymer-silica composite sorbents for clean-up and preconcentration. Sample clean-up for alkaloids (hydrastine and berberine) in goldenseal, Hydrastis canadensis and flavonoids (quercetin, kaempferol and isorhamnetin) in Ginkgo biloba was achieved using Bond Elut Plexa SPE sorbent. Clean-up of flavonoids in Ginkgo biloba was also achieved using electrospun polymer-silica composite (polystyrene-silica, polyacrylonitrile-silica and nylon 6-silica) sorbents. All analysis of flavonoids and alkaloids was carried out using an Agilent 1200 Series HPLC coupled with a diode array detector. Good peak separation was achieved in less than 6 min employing an Agilent ZORBAX Eclipse Plus C18 column (4.6 x 75 mm, 3.5 μm) at 35⁰C. The mobile phases employed were 0.1% phosphoric acid/methanol gradient and 0.5% phosphoric acid/methanol (40:60) for alkaloids and flavonoids respectively. The calibration curves exhibited linearity up to 120 μg mL⁻¹ with correlation coefficients of more than 0.9980. The recoveries ranged from 73-109% with relative standard deviation of less than 5% for all analytes. Agilent Chem Elut supported liquid extraction was employed for the development of a sample preparation method for the determination of 24 banned aromatic amines from azo dyes in textile following the EU standard method EN 14362-1:2003 (E) and the Chinese standard method GB/T 17592-2006. The supported liquid extraction was effective in the extraction of the aromatic amines from textile (cotton, wool and polyester/cotton [80%:20%]). Most of the recoveries obtained were conforming to the minimum requirements set in the EN 14362-1:2003 (E) standard method and the relative standard deviations were less than 15%. Good peak separation was obtained within 70 min run time using the Agilent Zorbax SB-Phenyl column (4.6 mm x 250 mm, 5-micron) or the Agilent DB-35 MS (J & W) (30 m x 0.25 mm, 0.25 μm film thickness. It was demonstrated that the polymeric Agilent Bond Elut Plexa, electrospun nanofibers and diatomaceous earth were effective in extraction of alkaloids, flavonoids and aromatic amines in different matrices. The developed methods were simple, rapid and reproducible.
Format: 147 p.
Format: pdf
Publisher: Rhodes University
Publisher: Faculty of Science, Chemistry
Language: English
Rights: Mothibedi, Kediemetse

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