Investigation of the colorimetric measurement of pH and metal ions by using reagents doped in sol-gel glasses for potential on-line monitoring

2.50
Hdl Handle:
http://hdl.handle.net/10547/582568
Title:
Investigation of the colorimetric measurement of pH and metal ions by using reagents doped in sol-gel glasses for potential on-line monitoring
Authors:
Javaid, Muhammad Azhar
Abstract:
Sol-gel porous glasses have been doped with indicator molecules for colorimetric measurements of pH and metal ions in solution. pH measurements were made in real time (20 seconds) to a wide pH range 3-8 by using bromophenol blue doped in sol-gel thin films. New methods of sol-gel coating on the inside of test tubes and tubing have been introduced for simple, non invasive, on the spot chemical sensing. pH indicator doped films were also successfully autoclaved for biological applications without affecting their chemical and physical properties. The pore structure of thin films has been controlled for minimising the effect of ageing on response time by introducing dimethyl formamide (DMF). The effect of light, temperature and salt on thin films have been studied. The results show that they are relatively stable between 20-31' C and less affected « 0.03 absorbance unit decrease in 3 weeks) by light. However their response to pH is changed by adding salt in solution with concentration higher than O.OlM. Fourier transform infra red (FTIR) study of films has been conducted to elucidate the effect of ageing, DMF and autoclaving on their chemical structures. It was found that ageing continues after four weeks of fabrication and addition of DMF helps to reduce ageing and increase porosity. The long term stability of these pH indicator doped films in various solvents has been established. Thin films on microscope slides were deposited by using a newly designed spin coater and have been demonstrated as reusable pH slides. Sol-gel films were also doped by different metal reagents. Eriochrome cyanine doped thin films were found to be sensitive to copper ions in solution. Copper (Cu++) was measured to a low concentration of 0.6 ppm. The effect of light and temperature on Eriochrome copper complex was studied. Interferences of other metal ions were examined. A fibre-optic pH sensor has been demon.strated by coating an optical fibre with a sol-gel film (0.8 J.1m thick) doped with bromophenol blue. The sensor has shown fast response (5 seconds) to pH changes from pH 3 to 8 and no leaching or cracking during repeated use. It is simple to fabricate and easy to use as an interchangeable pH fibre probe. It has potential application in biological processes as an integral part of an online monitoring system.
Citation:
Javaid, M.A. (1998) 'Investigation of the colorimetric measurement of pH and metal ions by using reagents doped in sol-gel glasses for potential on-line monitoring'. PhD thesis. University of Luton.
Publisher:
University of Bedfordshire
Issue Date:
Jul-1998
URI:
http://hdl.handle.net/10547/582568
Type:
Thesis or dissertation
Language:
en
Description:
A thesis submitted to the University of Luton for the degree of Doctor of Philosophy
Appears in Collections:
PhD e-theses

Full metadata record

DC FieldValue Language
dc.contributor.authorJavaid, Muhammad Azharen
dc.date.accessioned2015-11-24T09:46:10Zen
dc.date.available2015-11-24T09:46:10Zen
dc.date.issued1998-07en
dc.identifier.citationJavaid, M.A. (1998) 'Investigation of the colorimetric measurement of pH and metal ions by using reagents doped in sol-gel glasses for potential on-line monitoring'. PhD thesis. University of Luton.en
dc.identifier.urihttp://hdl.handle.net/10547/582568en
dc.descriptionA thesis submitted to the University of Luton for the degree of Doctor of Philosophyen
dc.description.abstractSol-gel porous glasses have been doped with indicator molecules for colorimetric measurements of pH and metal ions in solution. pH measurements were made in real time (20 seconds) to a wide pH range 3-8 by using bromophenol blue doped in sol-gel thin films. New methods of sol-gel coating on the inside of test tubes and tubing have been introduced for simple, non invasive, on the spot chemical sensing. pH indicator doped films were also successfully autoclaved for biological applications without affecting their chemical and physical properties. The pore structure of thin films has been controlled for minimising the effect of ageing on response time by introducing dimethyl formamide (DMF). The effect of light, temperature and salt on thin films have been studied. The results show that they are relatively stable between 20-31' C and less affected « 0.03 absorbance unit decrease in 3 weeks) by light. However their response to pH is changed by adding salt in solution with concentration higher than O.OlM. Fourier transform infra red (FTIR) study of films has been conducted to elucidate the effect of ageing, DMF and autoclaving on their chemical structures. It was found that ageing continues after four weeks of fabrication and addition of DMF helps to reduce ageing and increase porosity. The long term stability of these pH indicator doped films in various solvents has been established. Thin films on microscope slides were deposited by using a newly designed spin coater and have been demonstrated as reusable pH slides. Sol-gel films were also doped by different metal reagents. Eriochrome cyanine doped thin films were found to be sensitive to copper ions in solution. Copper (Cu++) was measured to a low concentration of 0.6 ppm. The effect of light and temperature on Eriochrome copper complex was studied. Interferences of other metal ions were examined. A fibre-optic pH sensor has been demon.strated by coating an optical fibre with a sol-gel film (0.8 J.1m thick) doped with bromophenol blue. The sensor has shown fast response (5 seconds) to pH changes from pH 3 to 8 and no leaching or cracking during repeated use. It is simple to fabricate and easy to use as an interchangeable pH fibre probe. It has potential application in biological processes as an integral part of an online monitoring system.en
dc.language.isoenen
dc.publisherUniversity of Bedfordshireen
dc.subjectC710 Applied Molecular Biology, Biophysics and Biochemistryen
dc.subjectcolorimetric measurementen
dc.subjectsol-gel porous glassen
dc.subjectsensorsen
dc.titleInvestigation of the colorimetric measurement of pH and metal ions by using reagents doped in sol-gel glasses for potential on-line monitoringen
dc.typeThesis or dissertationen
dc.type.qualificationnamePhDen_GB
dc.type.qualificationlevelPhDen
dc.publisher.institutionUniversity of Bedfordshireen
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