A Comparison of Sample Preparation Techniques for the Analysis of Drugs of Abuse in Oral Fluids

The analysis of drugs of abuse in oral fluids is an analytical method that is gaining popularity due to its less invasive collection technique compared to blood or urine. However, there are some unique challenges associated with oral fluid testing. It can be difficult to remove all of the surfactants and preservatives present in the oral fluid collection device’s buffer solution which can cause matrix effects and poor column lifetime. Often lengthy solid phase extraction procedures are utilized to address this challenge. Finding a method that uses a simple sample preparation paired with accurate and robust quantitation of the analytes is important for laboratories running these samples. An LC-MS/MS method was developed for the quantitation of drugs of abuse in oral fluid using a Biphenyl stationary phase. Samples were prepared in oral fluid and combined with QuantisalTM buffer. Samples were extracted using three different sample preparation techniques: salt-assisted liquid-liquid extraction (SALLE), supported liquid extraction (SLE), and dilute-and-shoot. The results of these extraction techniques were investigated and compared using performance metrics such as recovery, linearity, matrix effects, and accuracy and precision.