An ion beam analysis method to quantitatively measure the presence of fluorinated compounds in aqueous samples. The method is a quick, cost effective, nondestructive and quantitative, screen for the presence of fluorinated compounds in solution. The present invention includes a novel method of using an ion beam analysis method (such as PIGE) in air (ex vacuo) to unambiguously easily, quickly, accurately, precisely and cost effectively identify the presence of fluorinated compounds (such as PFASs) that have been extracted from aqueous solutions. The present invention may be used with a wide variety of aqueous solutions, including environmental groundwater samples, with little processing.