Membranes trace analysis

J. Liu, J. Chao, G. Jiang, Y. Cai and J. Liu, Trace analysis of sulfonylurea herbicides in water by on-line continuous flow liquid membrane extraction-C18 precolumn liquid chromatography with ultraviolet absorbance detection. J. Chromatogr.A 995 (2003) 21-28. 

Potentiometric sensors for trace analysis realized to date with detection limits and a brief description of membrane and inner solution composition... 

Trace analysis is usually a discontinuous process comprising several procedures in sequence sampling, enrichment, separation, and measurement. In this section a technique is described which intends to integrate all necessary procedures in order to facilitate continuous measurements. It combines reversible extraction of the analyte by membranes with the measurement of the absorption of its infrared bands. 

Table 6.3 Selected applications for membrane extraction in trace analysis...

Therefore a (semi-) continuous measuring methodology, like MS was considered. Trace analysis by MS via a membrane separator was known (2), but the decay times of the signal precluded breath-by-breath analysis. 

Membrane Extraction in Preconcentration, Sampling, and Trace Analysis... 

Jonsson, J. A., Mathiasson, L., Lindegard, B., Trocewicz, J., Olsson, A. M. (1994). Automated system for the trace analysis of organic compounds with supported hquid membranes for sample enrichment. J. Chromatogr. A, 665, 259-68. 

Recently, Psillakis et al. " have developed a liquid phase microextraction (LPME) technique using a hollow fiber membrane in conjunction with GC-MS for the extraction and analysis of phthalates. The resulting method was validated and compared with SPME. Both techniques showed comparable performance and were considered suitable for trace analysis of phthalates in water. 

Other areas of interest include stabilization of noncommon oxidation states, solvent extraction of cations, transfer of cations through membranes, isotopic separation, detoxification of harmful and radioactive metals, metal recovery, metal trace analysis, ion chromatography on polymer-supported cryptands, and chromo- and fluoro-ionophores. More organic-chemistry-orientated applications can be mentioned, including enhancement of metal salt solubility in organic solvents, anion activation, phase-transfer catalysis, and anionic polymerization. Many of these applications are covered in other articles in this encyclopedia as well as in the literature. 

Wan, C. Harrington, P.B. Davis, D.M., Trace analysis of BTEX compounds in water with a membrane interfaced ion mobihty spectrometer, Talanta 1998,46, 1169-1179. 

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