Wooden toothpicks coated with nylon-6 coupled to DI-MS, a high throughput alternative for the determination of 3 drugs of abuse in saliva
In our latest research, wooden toothpicks (WTs) coated with a commercial polyamide such as nylon-6 (N6) were used in a solid phase microextraction (SPME) procedure for the determination of methadone, cocaine, and methamphetamine in saliva. Bare WTs present weak hydrophilic and hydrophobic forces provided by cellulose and lignocellulose, respectively. Consequently, the N6 polymeric coating was used to reinforce the hydrogen bonds and hydrophobic forces with the target analytes. The synthesis of N6-WTs is based on the dip coating technique, where the superficial -OH groups provided by the (ligno)cellulosic components of wood allow the coating of the WTs. This simple dipping-and-drying process consists of the immersion of the WTs in a N6 precursor solution (3 % (w/v) in formic acid), followed by the evaporation of the solvent to anchor the thin polymeric phase to the surface of the WTs. The synthesized sorbents were characterized by attenuated total reflection infrared spectroscopy (A