A Sensitive XRF Screening Method for Lead in Drinking Water.

A novel method for quickly and quantitatively measuring aqueous lead in drinking water has been developed. A commercially available activated carbon felt has been found to effectively capture lead from tap water, and partnered with X-ray fluorescence (XRF) spectrometry, it provides quantitative measurement of aqueous lead in drinking water. Specifically, for a 2 L volume of tap water, the linear range of detection was found to be from 1-150 ppb, encompassing the current EPA limit for lead in drinking water (15 ppb). To make a reproducible and easy to use method for filtering, a 2 L bottle cap with a 1.25 cm diameter hole was used for filtering. Utilizing this filtration method, 75 solutions from 0 to 150 ppb lead gave a 91% sensitivity, 97% specificity, and 93% accuracy, and all the misclassified samples fell between 10 and 15 ppb. This method has also proved reliable for detecting calcium as well as several other divalent metals in drinking water including copper, zinc, iron, and manganese.