UiO-66-NH2: a recyclable and efficient sorbent for dispersive solid-phase extraction of fluorinated aromatic carboxylic acids from aqueous matrices.

Abstract

The present study describes the trace analysis of 23 fluorinated aromatic carboxylic acids based on the dispersive solid-phase extraction (dSPE) technique using UiO-66-NH2 MOF as efficient, recyclable sorbent, and GC-MS negative ionization mass spectrometry (NICI MS) as determination technique. All 23 fluorobenzoic acids (FBAs) were enriched, separated, and eluted in a shorter retention time; the derivatization was done by pentafluorobenzyl bromide (1% in acetone), in which the use of inorganic base K2CO3 was improved by triethylamine to increase the lifespan of the GC column. The performance of UiO-66-NH2 was evaluated by dSPE in Milli-Q water, artificial seawater, and tap water samples, and the impact of various parameters on the extraction efficiency was investigated by GC-NICI MS. The method was found to beprecise, reproducible, and applicable to the seawater samples. In the linearity range, the regression value was foundto be >0.98; LOD and LOQ were foundto be in the range of0.33-1.17ng/mL and 1.23-3.33ng/mL, respectively; and the value of theextraction efficiency was found to range between 98.45 and 104.39% for Milli-Q water samples, 69.13-105.48% for salt-rich seawater samples, and 92.56-103.50% for tap water samples with amaximum RSD value of6.87% that confirms the applicability of the method to different water matrices.