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Liquid Membrane Techniques for Trace Metal Analysis and Speciation in Environmental and Biological Matrices

Ndung'u, Kuria LU (1999)
Abstract
In this thesis, liquid-membrane-based methods for the analysis of trace metal species in samples of environmental and biological origin were developed. By incorporating extracting reagents in the membrane liquid, trace metal ions were selectively separated from humic-rich natural waters and urine samples, prior to their determination using various instrumental techniques. The extractions were performed in closed flow systems thus allowing easy automation of both the sample clean-up and enrichment. An acidic organophosphorus reagent (DEHPA) and a basic tetraalkylammonium reagent (Aliquat-336) were used as extractants in the membrane liquid to selectively extract and enrich cationic and anionic metal species respectively.



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In this thesis, liquid-membrane-based methods for the analysis of trace metal species in samples of environmental and biological origin were developed. By incorporating extracting reagents in the membrane liquid, trace metal ions were selectively separated from humic-rich natural waters and urine samples, prior to their determination using various instrumental techniques. The extractions were performed in closed flow systems thus allowing easy automation of both the sample clean-up and enrichment. An acidic organophosphorus reagent (DEHPA) and a basic tetraalkylammonium reagent (Aliquat-336) were used as extractants in the membrane liquid to selectively extract and enrich cationic and anionic metal species respectively.



A speciation method for chromium species was developed that allowed the determination of cationic Cr(III) species and anionic Cr(VI) species in natural water samples without the need of a chromatographic separation step prior to their detection. SLM was also coupled on-line to potentiometric stripping analysis providing a fast and sensitive method for analysis of Pb in urine samples. A microporous membrane liquid-liquid extraction (MMLLE) method was developed for the determination of organotin compounds in natural waters that reduced the number of manual steps involved in the LLE of organotin compounds prior to their GC separation. Clean extracts obtained after running unfiltered humic-rich river water samples through the MMLLE flow system allowed selective determination of all the organotin compounds in a single run using GC-MS in the selected ion monitoring mode (SIM). (Less)
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author
opponent
  • Prof Bruland, K.
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Analytical chemistry, Pb and Organotin species, MMLLE, SLM, GC/MS, PSA, GFAS, FAAS, ICP-MS, Speciation, DEHPA, Aliquat-336, trace metals, Cr(III), Cr(VI), Analytisk kemi
pages
165 pages
publisher
Department of Analytical Chemistry, Lund University
defense location
Lecture Hall B
defense date
1999-05-20 10:15
external identifiers
  • Other:ISRN: LUNKDL/NKAK-1049/1-165 (1999)
language
English
LU publication?
yes
id
c3f59b07-6f1e-42c9-8a88-4da5a31efbcd (old id 39713)
date added to LUP
2007-08-01 15:46:24
date last changed
2016-09-19 08:45:01
@misc{c3f59b07-6f1e-42c9-8a88-4da5a31efbcd,
  abstract     = {In this thesis, liquid-membrane-based methods for the analysis of trace metal species in samples of environmental and biological origin were developed. By incorporating extracting reagents in the membrane liquid, trace metal ions were selectively separated from humic-rich natural waters and urine samples, prior to their determination using various instrumental techniques. The extractions were performed in closed flow systems thus allowing easy automation of both the sample clean-up and enrichment. An acidic organophosphorus reagent (DEHPA) and a basic tetraalkylammonium reagent (Aliquat-336) were used as extractants in the membrane liquid to selectively extract and enrich cationic and anionic metal species respectively.<br/><br>
<br/><br>
A speciation method for chromium species was developed that allowed the determination of cationic Cr(III) species and anionic Cr(VI) species in natural water samples without the need of a chromatographic separation step prior to their detection. SLM was also coupled on-line to potentiometric stripping analysis providing a fast and sensitive method for analysis of Pb in urine samples. A microporous membrane liquid-liquid extraction (MMLLE) method was developed for the determination of organotin compounds in natural waters that reduced the number of manual steps involved in the LLE of organotin compounds prior to their GC separation. Clean extracts obtained after running unfiltered humic-rich river water samples through the MMLLE flow system allowed selective determination of all the organotin compounds in a single run using GC-MS in the selected ion monitoring mode (SIM).},
  author       = {Ndung'u, Kuria},
  keyword      = {Analytical chemistry,Pb and Organotin species,MMLLE,SLM,GC/MS,PSA,GFAS,FAAS,ICP-MS,Speciation,DEHPA,Aliquat-336,trace metals,Cr(III),Cr(VI),Analytisk kemi},
  language     = {eng},
  pages        = {165},
  publisher    = {ARRAY(0x8b3ad80)},
  title        = {Liquid Membrane Techniques for Trace Metal Analysis and Speciation in Environmental and Biological Matrices},
  year         = {1999},
}