Séminaire Grégoire Herzog

Reducing limits of detection and improving sensitivity is a never-ending quest for the analytical chemist. Part of this task lies with sample preparation and analyte preconcentration. Solid phase and liquid-liquid extractions are two-step procedures based on species partitioning governed on hydrophobicity/ hydrophilicity balance, complexation, pH, or ion-pairing. However, the extraction of hydrophilic compounds such as metformin, an antidiabetic drugs (diabetes type II), remains a challenge. A new sample preparation method is proposed for the extraction of pharmaceutical compounds (Metformin, Phenyl biguanide, and Phenformin) of varied hydrophilicity, dissolved in an aqueous sample.¹ When in contact with an organic phase, an interfacial potential is imposed by the presence of an ion, tetramethylammonium (TMA⁺), common to each phase. The interfacial potential difference drives the transfer of ionic analytes across the interface and allows it to reach up to nearly 100% extraction efficiency and a 60-fold enrichment factor in optimized extraction conditions as determined by HPLC analysis.