The Benefits of 2.1 mm Internal Diameter Analytical Columns for the Analysis of Drugs of Abuse by LC-MS/MS

The biphenyl phase offers advantageous selectivity compared to a C18 column for drugs of abuse panels, but choosing the right column dimension is paramount to obtain robust and accurate data. Every column dimension can be advantageous in different scenarios, but generally clinical labs are all working towards the same goals: high throughput, low sample volume, good sensitivity, and low cost. We developed two methods to analyze common isobars in drugs of abuse panels on Raptor Biphenyl columns using methanol and water modified with 0.1% formic acid and column oven set to 45 ⁰C. These methods were compared for efficiency, sensitivity, resolution (Rs), consumption of mobile phase, and robustness. In this work, the advantage of the 2.1 mm ID column, which demonstrated superior sensitivity while consuming less resources and minimizing impact to the MS while still providing adequate resolution of isobars and excellent column robustness, is discussed and demonstrated for the analysis of drugs of abuse.