Chromatographic analyzers

Simultaneous determination of both cations and anions in acid rain has been achieved using a portable conductimetric ion-exclusion cation-exchange chromatographic analyzer.14 This system utilized the poly(meth-ylmethacrylate)-based weak acid cation exchange resin TSK-Gel OA-PAK-A, (Tosoh , Tokyo, Japan) with an eluent of tartaric acid-methanol-water. All of the desired species, 3 anions and 5 cations, were separated in less than 30 minutes detection limits were on the order of 10 ppb. Simultaneous determination of nitrate, phosphate, and ammonium ions in wastewater has been reported utilizing isocratic IEC followed by sequential flow injection analysis.9 The ammonium cations were detected by colorimetry, while the anions were measured by conductivity. These determinations could be done with a single injection and the run time was under 9 minutes. 

Tanaka, K., Ohta, K., Haddad, P. R., Fritz, J. S., Lee, K.-R, Hasebe, K., Ieuji, A., and Miyanaga, A., Acid-rain monitoring in East Asia with a portable-type ion-exclusion cation-exchange chromatographic analyzer, ]. Chromatogr. A, 850, 311, 1999. 

F. Reche, M.C. Garrigos, M.L. Marin and A. Jimdnez, Abstracts 7th Inti. Symposium on Hyphenated Techniques in Chromatography and Hyphenated Chromatographic Analyzers (HTC-7), Bmges (2002), paper P132. 

Techniques in Chromatography and Hyphenated Chromatographic Analyzers (HTC-7), Bruges (2002), Paper P80. 

Figure 2 shows that the path through the Data Handling Menu is quite restricted, in that some functions cannot be performed without first performing others. This is done because the chromatograph analyzes a group of specimens in one continuous operation (batch mode). Each set of data must be associated with pertinent archival data. 

Furthermore, many bioassay procedures can be affected synergis-tically or antagonistically by artifacts. In current practice, chemists use various solvents to clean the resin as completely as possible, run a resin blank, and chromatographically analyze the blank sample. Rarely are the artifacts identified. This procedure does not help the biologist who requires a blank that does not show a positive response in the bioassay test of the blank. Biologists usually clean the resin as the chemists do and complete a blank for the bioassay. Artifacts should be identified to assure that the bioassay results are in response to the compounds under study and not the artifacts in combination with the sample. 

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