A derivatization strategy for the detection and identification of volatile trialkylphosphites using liquid chromatography-online solid phase extraction and offline nuclear magnetic resonance spectroscopy.

We demonstrate herein the application of selective derivatization method that converts volatile and labile trialkylphosphites (TAPs) into virtually non-volatile, thermally stable, and UV absorbing derivatives. After simple sample preparation, purification/enrichment of the derivatives was achieved by using high performance liquid chromatography (HPLC) coupled to on-line post column solid phase extraction (SPE) system. These derivatives were subjected to (31)P{(1)H} NMR and 1D-selTOCSY experiments. Conclusive identification was achieved on the basis of their HPLC retention time and NMR spectral signatures ( [Formula: see text] , (n)JH-H, and (3)JP-H). This method was tested for the unambiguous identification of a mixture containing low concentrations (∼10µgmL(-1)) of trimethylphosphite (TMP), triethylphosphite (TEP), triisopropylphosphite (TIP), and tributylphosphite (TBP) along with a high concentration of irrelevant background chemicals. It offered a high dynamic range and good detection limit and recovery (>75%) without the need for special NMR probe heads or exotic NMR experiments.