This is a question that I am often asked by very smart people that just haven’t had time to learn the process. An optimized sample preparation method is critical for an accurate, specific, robust clinical LC-MS/MS assay. A good sample prep method can improve accuracy and precision, provide longer LC column lifetime, and keep your LC-MS/MS system clean.

Most clinical and forensic labs have a used a traditional approach for drug testing called screen with reflex to confirmation. This involves analyzing samples using an immunoassay technique that identifies a drug class. Positive immunoassay results are then analyzed by a second more specific method, like GC-MS or LC-MS/MS, to identify and quantitate specific drug analytes.  

LC/MS/MS seems to be the gold standard in sample analysis nowadays. However, some labs are still analyzing samples using GC/MS. The majority of published peer-reviewed articles are for LC/MS/MS, so those working with GC/MS instrumentation may not know how to change the sample preparation to better fit GC/MS.

Analytical laboratories using techniques such as LC-MS/MS or GC-MS are continuously searching for ways to increase throughput, reduce turnaround times and lower costs. Sample prep is often an underestimated component in this process, but is a critical step that removes matrix interferences, concentrates samples, and also protects expensive analytical instrumentation.