Solid-phase extraction of alkylphosphonic and O-alkyl alkylphosphonic acids followed by HPLC separation using porous graphitic carbon sorbent

Abstract

An HPLC separation of alkyl phosphonic acids on porous graphitic carbon adsorbent Hypercarb, based upon a step gradient of formic acid concentration in an aqueous mobile phase, was evaluated in this study. Analytes were detected by single quadrupole and triple quadrupole MS. Good separation was achieved for methyl phosphonic acid, ethylphosphonic acid, n-propylphosphonic acid, isopropylphosphonic acid, ethyl methylphosphonic acid, isopropyl methylphosphonic acid, isobutyl methylphosphonic acid, pinacolyl methylphosphonic acid. Solid-phase extraction of these analytes on Hypercarb was also proposed, desorption was carried out with aqueous ammonium formate and water-methanol mixtures. LODs were 0.1–0.2 ng mL−1 for these analytes without SPE; solid-phase extraction resulted in the decrease of LODs at least 100-fold. Accuracy was proven by analyses of spiked samples of river water and snow meltwater.