b S Supporting Information O ne of the biggest challenges in trace organic analysis is concentrating any given sample enough to reliably identify and quantitate above the method detection limit. There are several ways to do this depending on the sample matrix. For aqueous samples, liquidÀliquid extraction can be used to partition an analyte to the organic solvent layer. Another example is solid-phase extraction (SPE) where the aqueous layer is passed through a solid phase to selectively extract the analyte of interest. SPE offers a variety of advantages over liquidÀliquid extraction because (i) different solid phases can be used to selectively partition analytes from the aqueous phase, (ii) large sample volumes can be passed through the SPE column, and (iii) organic solvent use is minimized. Similar experiments published in this Journal have used SPE to isolate and GCÀMS to quantitate and characterize trace organic components. 1À4 Trace organic analysis is especially important for compounds that pose human health and environmental risks. One compound that has received considerable research and public interest is bisphenol-A (4-4 0 -isopropylidenediphenol) (Figure 1) due to its endocrine disrupting properties. 5 Bisphenol-A (BPA) is a monomer used in polycarbonate plastic products and other products such as epoxy resins, adhesives, optical coatings, and so forth. 6 Recently, it has been shown that BPA is leached from a wide variety of products such as bottles, plastic food wrappers, and resin-lined food cans. 7,8 One method that is suitable for the detection and quantitation of trace organic compounds is gas chromatographyÀmass spectrometry (GCÀMS).GCÀMS is ideal for undergraduate level experiments because it is used in many fields of chemistry in both academic and industrial settings due to its low cost, ease of use, and minimum