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Pervaporation as an alternative to headspace
D W Bryce1, A Izquierdo, M D Luque de Castro
1Department of Analytical Chemistry, Faculty of Sciences, University of Córdoba, E-14004 Córdoba, Spain.
Analytical Chemistry
|June 7, 2011
Summary
Pervaporation coupled with gas chromatography offers a new method for analyzing organomercury compounds in solid samples. This technique provides accurate speciation and improved detection limits compared to traditional headspace methods.
Area of Science:
- Analytical Chemistry
- Environmental Science
- Environmental Chemistry
Background:
- Organomercury compounds pose significant environmental and health risks.
- Accurate speciation of mercury in solid matrices is crucial for risk assessment.
- Existing methods like headspace gas chromatography (GC) have limitations.
Purpose of the Study:
- To propose and validate pervaporation as an alternative to headspace for organomercury speciation.
- To couple pervaporation with GC for the first time for this application.
- To analyze specific organomercury species (Me2Hg, Et2Hg, MeHgCl) without derivatization.
Main Methods:
- Solid samples were analyzed using pervaporation coupled to GC.
- Organomercury compounds were separated from the matrix via pervaporation.
- Analytes were preconcentrated on a Tenax minicolumn.
- Separation was achieved on an HP-1 semicapillary column.
- Detection was performed using atomic fluorescence spectroscopy.
Main Results:
- The pervaporation-GC system enabled speciation of dimethylmercury, diethylmercury, and methylmercury chloride without derivatization.
- Linear ranges and detection limits were comparable or slightly better than headspace GC.
- Excellent recoveries (95-107%) were achieved for spiked complex solid samples.
- No column degradation was observed during the analysis.
Conclusions:
- Pervaporation is a viable and effective alternative to headspace for organomercury speciation in solid samples.
- The developed method is simple, easily automated, and offers high accuracy and efficiency.
- This technique advances the analytical capabilities for environmental mercury monitoring.
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