Determination of alkylphenols and alkylphenol mono- and diethoxylates in environmental samples by high-performance liquid chromatography

Abstract

A routine method is described for the quantitative determination of 4-nonylphenol (NP) and 4-nonylphenol mono(NP1EO) and diethoxylate (NP2EO) In samples from wastewater and sludge treatment and from the aquatic environment. An exhaustive steam-distillation/solvent-extraction procedure was employed to enrich the analytes from aqueous and solid samples. Quantitative determinations were performed by normal-phase high-performance liquid chromatography (HP-LC) using aminosillca columns. Relative standard deviations were 3.0-4.4% In a river water containing 3.9 μg/L NP, 23.4 μg/L NP1EO, and 9.4 μg/L NP2EO. A digested sewage sludge with 1.6 g of NP/kg of dry matter was analyzed with a relative standard deviation of 3.7%. Recoveries were higher than 80%, and the estimated detection limit In water samples was 0.5 μg/L. Reversed-phase HPLC on octylsllica provided complementary qualitative data, particularly on homologous alkylphenolic compounds. Good agreement was found between quantitative determinations by HPLC and by high-resolution gas chromatography with flame lonization detection and directly coupled mass spectrometry. Municipal wastewater effluents, sewage sludges, and natural waters were analyzed to demonstrate the method's broad applicability.