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Divalent metal ion-sensitive holographic sensors [An article from: Analytica Chimica Acta]


by B. Madrigal Gonzalez, G. Christie, C.A.B Davidson

List Price: $10.95
Available: Available for download now
Studio: Elsevier
Binding: Digital
Publication Date: January 10, 2005
Publisher: Elsevier


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Product Description
This digital document is a journal article from Analytica Chimica Acta, published by Elsevier in 2005. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

Description:
A holographic sensor for real-time detection of divalent metal ions (Ca^2^+, Mg^2^+, Ni^2^+, Co^2^+ and Zn^2^+) has been fabricated by incorporating a chelating monomer into a hydrogel matrix. A methacrylated analogue of iminodiacetic acid (IDA) was prepared and co-polymerised with hydroxyethyl methacrylate (HEMA) and ethylene glycol dimethacrylate (EDMA) as a cross-linker to form polymer films. A silver-based reflection hologram was incorporated into the hydrogel by diffusion followed by holographic recording using a frequency-doubled Nd/YAG laser. Changes in the replay wavelength of the hologram were used to characterise the swelling behaviour of the matrix as a function of its chemical composition and concentration of analyte in the media. The effects of active monomer, cross-linker, pH and ionic strength on the swelling of the matrix and on metal detection sensitivity have been studied. Polymers containing >10mol% of chelating monomer and 6mol% of cross-linker showed significant responses (46.3nm) within 30s at an ion concentration of 0-40nm. The selectivity of the holograms towards the different ions tested was Ni^2^+>Zn^2^+>Co^2^+>Ca^2^+>Mg^2^+. The sensor showed fully reversible responses, permitting real-time monitoring of calcium ion efflux during the germination of Bacillus megaterium spores.
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