Membrane chromatographic system

Gerstner, J. A., Hamilton, R., and Cramer, S. M. (1992). Membrane chromatographic systems for high-throughput protein separations. J. Chromatogr. 596, 173-180. 

Liu, X. and J. Pawliszyn. 2005. On-site environmental analysis by membrane extraction with a sorbent interface combined with a portable gas chromatograph system. Int. J. Environ. Anal. Chem. 85 1189-1200. 

High efficiency denuders that concentrate atmospheric S02 were coupled to an ion chromatograph to yield detection limits on the order of 0.5 ppt (106). A newer approach has been introduced for the quantitative collection of aerosol particles to the submicrometer size (107). When interfaced to an inexpensive ion chromatograph for downstream analysis, the detection limit of the overall system for particulate sulfate, nitrite, and nitrate are 2.2,0.6, and 5.1 ng/m3, respectively, for an 8-min sample. A two-stage membrane sampling system coupled with an ion trap spectrometer has been utilized for the direct analysis of volatile compounds in air, with quantitation limits to low ppt levels (108). Toluene, carbon tetrachloride, tricholoroethane, and benzene were used in these studies. The measurement of nitrogen dioxide at ppb level in a liquid film droplet has been described (109) (see Air pollution). A number of elements in environmental samples have been determined by thermal ionization ms (Table 6). The detection limit for Pu was as low as 4 fg. 

One of the instruments obtained by ERDA will be evaluated at ORNL to assess its potential as a monitor for hazardous by-products from alternative energy sources. Investigations to determine the desirability of a membrane inlet system for concentrating organic vapors are planned. The feasibility of using a portable gas chromatograph with the portable mass spectrometer, when a complex mixture analysis is required, is also being studied. 

Melcher RG and Morabito PL. Membrane/gas chromatographic system for automated extraction and determination of trace organics in aqueous samples. Anal. Chem. 1990 62 2183-2188. 

Carabias Martinez R, Rodriguez Gonzalo E, Hernandez Fernandez E, and Hernandez Mendez J. Membrane extraction - preconcentration cell coupled on-line to flow-injection and liquid chromatographic systems. Determination of triazines in oil. Anal. Chim. Acta 1995 304 323-332. 

The sample solutions injected into an ion chromatographic system must be free of particulate matter to avoid plugging of the capillary connecting tubing and the frits at the head of the analytical column. Even samples that appear to be clear may contain unsuspected fine particles. It is more or less standard procedure to filter sample solutions prior to their injection. Disposable membrane filters with a pore diameter of... 

MAJOR APPLICATIONS Membranes, chromatographic resins, size exclusion particles, drug delivery systems. 

The application of potentiometric detection in ion-chromatography is favoured by the progress in the field of membrane ion-selective electrodes (ISE). The electrodes with solid-state membranes were mostly employed for determination of halides, pseudohalides and some other anions binding silver ions. The use of fluoride electrode in multidetector, chromatographic system offers very low detection limit of 1.2 ng fluoride in injected samples. Application of bromide electrode in the same system provides even five-fold better detectability. The same level of detectability was reported by Butler and Gershey for iodide with iodide ISE. In the system with preconcentration step the detectability can be lowered by an order... 

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