Method (metal indicator detection) for the complexometric determination of oxyanions/polyanions at picomole sensitivity, use for the continuous post-column detection in liquid chromatographic separation and for detection after separation on thin layer supports

摘要

The designated invention provides a new complexometric method which is suitable for detecting oxyanions and polyanions after their liquid chromatographic separation using a continuous post-column method at down to picomole sensitivity. The method of the invention is also suitable for detecting such anions separated on thin layer supports. The ternary detection principle always used in the same manner is based on the fact that polyanions and polyvalent oxyanions form, at sufficiently high pH, high-affinity complexes with a series of polyvalent cations. This complex formation can in turn be made visible (visualised) by the simultaneous presence of a cation indicator specific to the cations used. The detection signal which can be evaluated is in each case the reduction in the cation-specific signal of the indicator always when (for post-column detection) or where (for thin layer supports) the presence of competing polyanions or oxyanions has resulted in these binding a part of the polyvalent cations, i.e. the indicator substance is removed.