Saliva test is one of the easiest, costeffective and most accurate ways to measure the presence of drugs in the body. Collecting saliva sample is relatively non- invasive, easier to procure and reduced risk of sample adulteration. However, saliva matrix display much lower levels of drug compounds compared to urine samples, making the need to test at lower cut-off levels more important. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is a technique of choice for both screening and confirmation lower levels because it is sensitive, specific, and accurate.

Solid Phase Extraction (SPE) is widely used for sample clean up before LCMS/MS analysis. It is costly and time consuming. Here we present a high throughput, cost effective and sensitive procedure for screening and confirmation of Pain Panel Drugs (PPDs) in Synthetic Saliva using Thomson filter vial for sample preparation and using an integrated On-Line Extraction (OLE)- UHPLC-MS/MS System for sample analysis. The lower limit of quantitation (LLOQ) was 0.01-0.2 ng/mL and upper limit of quantitation (ULOQ) was 100 ng/mL. The linearity regression coefficient R2 was >0.99. The blanks show no interference of the analysis at the LLOQ level. The sub ng/mL level PPDs detection with about three orders of dynamic detection range will cover the clinical research needs.