Quantification of Acrylic Acid and Its Conjugate Base, Acrylate, in Aqueous Samples Using High-Performance Liquid Chromatography with Absorbance Detection

Acrylic acid is produced in industry as a polymerizing agent with many commercial applications, and it is also present in the natural environment including the atmosphere, freshwater systems, and the oceans. However, the detection and study of acrylic acid in environmental settings is rare due to the lack of a simple and sensitive analytical method suitable for aqueous samples. Herein, a high-performance liquid chromatographic (HPLC) method was developed to quantify nanomolar acrylic acid concentrations in water. The method is based on the precolumn derivatization of aqueous solutions of acrylic acid with o-thiosalicylic acid to produce the derivative, 2-[(2-carboxyethyl)thio]benzoic acid, followed by reversed phase HPLC separation and absorbance detection at 257 nm. Small samples (ca. 3 mL) are derivatized directly in water without the need for extraction into an organic phase. The HPLC-separated derivative peak was identified using high-resolution mass spectrometry. The method is highly sensitive with a limit of detection of 0.2 nM, more than 1 order of magnitude lower than previously published techniques. This method was used to measure acrylate in a range of samples from freshwater and low-salinity estuarine waters with high organic carbon content to marine waters with low biological productivity and dissolved organic matter content.