Identity Efficiency for High-Performance Ambient Pressure Ion Mobility Spectrometry

Area of Science:

• Analytical Chemistry
• Spectrometry
• Forensic Science

Background:

• Electrospray ionization high-performance ion mobility spectrometry (ESI-HPIMS) is used for detecting drugs and explosives.
• High false-positive rates are a common challenge in ESI-HPIMS detection.
• Existing methods struggle to reliably differentiate target compounds from interfering substances.

Purpose of the Study:

• To introduce and evaluate a novel parameter, conditional reduced mobility (CRM), for improving ESI-HPIMS specificity.
• To assess CRM's ability to differentiate between true drug peaks and false-positive signals.
• To compare CRM with other performance metrics like resolving power (R(m)) and diffusion-limited conditional theoretical reduced mobility (DLCTRM).

Main Methods:

• Developed conditional reduced mobility (CRM) by combining reduced mobility and peak width-at-half-height.
• Tested CRM using 11 different drugs and 7 common interfering substances.
• Compared CRM, R(m), and DLCTRM performance in an ESI-HPIMS setup.

Main Results:

• Conditional reduced mobility (CRM) demonstrated a significant ability to differentiate between target drug compounds and false-positive peaks.
• Observed up to a 74% difference between target compounds and interferences using CRM.
• Reproducibility of reduced mobility for target compounds was within 2% for ESI-HPIMS.

Conclusions:

• Conditional reduced mobility (CRM) is a valuable new parameter for enhancing the accuracy of ESI-HPIMS.
• CRM can effectively reduce false-positive rates in the detection of drugs and explosives.
• The findings suggest CRM can predict conditions for differentiating target compounds from false positives based on ion drifting patterns.