Donor Phase pH

Factors affecting the extraction recovery are pH of the donor phase, pH of the acceptor phase (in case of a three-phase LPME), composition of the SLM, and extraction time. 

As with other extraction techniques based on partitioning of the analyte between an aqueous phase and a nonpolar phase, it is of principal importance to suppress ionization. The pH of the donor phase needs to be basic, ideally 2 pH units higher than their pfQ value, to deprotonate basic analytes. The pH of the donor phase needs to be acidic, ideally 2 pH units lower than their pfCa value, to protonate acidic analytes. 

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