Determination of Xylitol in Sugar-Free Gum by GC-MS with Direct Aqueous Injection: A Laboratory Experiment for Chemistry Students

Proficiency with instrumental analysis via GC-MS is an important skill for chemistry students. The application of analytical techniques and fundamental theoretical principles to real-world problems can be valuable learning exercises for undergraduates which can also improve their analytical thinking skills. Xylitol is generally considered safe for human consumption and is frequently used in sugar-free gum; however, it is extremely toxic to dogs. In this laboratory experiment, upper-level undergraduate chemistry students extract xylitol from both fresh and chewed gum sticks followed by direct aqueous injection GC-MS analysis. Students learn the proper steps and techniques required for sample extraction and preparation and GC--MS analysis, and they determine concentrations of xylitol present in gum samples. Identification and quantification of the chemical components in gum extract occurs via GC-MS analysis; however, other GC detectors could be used. Students also compare external and internal standard calibration methods for xylitol quantification. Upon quantification of xylitol in chewed and unchewed gum samples, students are able to calculate the level of hazard for dogs upon ingestion.