Abstract:

A simple derivatization method followed by high performance liquid chromatography (HPLC) for the analysis of perfluorooctanoic acid (PFOA) was developed. PFOA was firstly derivatized with 3,4-dichloroaniline (DCA) using carbodiimide method. The typical amidate product was characterized by mass spectrometry (MS). It can be detected by a UV detector at maximum absorption wavelength of 255 nm. It was isolated well by methanol/H₂O (8/2, v/v) as mobile phase. The DCA derivatization of PFOA in organic or aqueous solutions was optimized. The following purification procedures with thin layer chromatography (TLC) and HPLC separations were established. Using external standard method with the authentic PFOA-DCA derivative as standard, the limit of instrumental quantification was found to be 0.5 mg/L. Good linear correlation coefficients were observed in 0.5-50.0 mg/L. The accuracy of the method was evaluated by the recovery measurements on spiked samples. The recoveries for the spiked samples (1.0 mg/L) in organic phase and aqueous phase were 91.8%-108.7% and 42.1%-53.7%, respectively. Comparing to the reported pre-column derivatization methods followed by HPLC for the determination of PFOA, this method has the advantages of mild reaction conditions, very stable derivative, easy operation, low cost, etc. The method was successfully applied for the quantification of PFOA in photodegradation experiments, and the results were consistent with those determined by LC/MS. Considering the combination of the preconcentration step, it has a potential for the application of the analysis of samples containing relatively low concentrations, such as μg/L levels of PFOA obtained from environmental or scientific experiments.

Key words: dicyclohexylcarbodiimide (DCC), high performance liquid chromatography (HPLC), perfluorooctanoic acid, pre-column derivatization, ultraviolet (UV) detection