Below detection, limit chromatographic interference

Concentration of an analyte prior to measurement may be necessary where the level is likely to be dose to or below the practical detection limit of the technique to be used. Solvent extraction and ion-exchange may be used for this purpose. Where a complex and/or contaminated ( dirty ) sample is to be analysed, a clean-up procedure is often employed before determination of the analyte(s). This is designed to avoid interference by other components of the sample, i.e. the matrix, and is particularly desirable prior to a gas or liquid chromatographic separation as the quality of the chromatography can be greatly improved and the working life of the column extended. 

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