Evaluation of Variable Data Independent Acquisition (vDIA) Approach for Nontarget Screening of Veterinary Drugs in Animal Feed

Significance of the Topic

Comprehensive screening of veterinary drug residues in animal feed is critical for food safety, regulatory compliance, and consumer protection. High-resolution mass spectrometry has enabled simultaneous targeted and non-targeted analysis, but classical approaches may miss low-abundance compounds or suffer from background interference.

Objectives and Study Overview

This study assessed a variable Data Independent Acquisition (vDIA) strategy on a quadrupole-Orbitrap instrument to improve qualitative and quantitative screening of 150 veterinary drugs in complex feed matrices. The new scan mode was compared against data-dependent MS2 (ddMS2) with inclusion lists and All Ion Fragmentation (AIF).

Methodology and Instrumentation

• Sample Preparation: Mixed piglet feed was spiked to levels of 50 ppt, 500 ppt, 5 ppb, and 25 ppb for each of 150 standards.
• Chromatography: Thermo Scientific UltiMate 3000 Binary RSLC with Accucore C8 column and a water/acetonitrile gradient (0.01% formic acid) over 20 min.
• Mass Spectrometry: Q Exactive Focus Orbitrap in positive/negative ESI. vDIA divided m/z 100–1000 into variable windows for MS2 at 17,500 FWHM. ddMS2 and AIF modes used standard full scans at 70,000 FWHM.
• Data Processing: Thermo TraceFinder software applied accurate mass, isotope pattern, fragment ion, retention time, and intensity criteria.

Main Results and Discussion

• vDIA spectra showed cleaner extracted ion chromatograms and reduced background versus AIF.
• Co-eluted analytes that escaped ddMS2 triggering (e.g. Azure A) were consistently detected and confirmed by vDIA.
• vDIA confirmed up to 96% of spiked compounds and maintained about 85% confirmation below 5 ppb.
• Quantitative performance exhibited broad linear ranges and low limits of quantitation across the analyte panel.

Benefits and Practical Applications

The vDIA approach combines non-targeted screening, retrospective data mining, confirmation, and quantitation in a single run. It enhances fragment ion sensitivity and selectivity without pre-filtering, supporting routine QA/QC and research workflows in food safety laboratories.

Future Trends and Applications

Advancements in dynamic window optimization and real-time acquisition control could further improve vDIA efficiency. Integration with machine-learning algorithms for automated feature extraction and suspect screening will expand capabilities for emerging contaminants.

Conclusion

The variable DIA strategy on a high-resolution Orbitrap platform outperformed traditional ddMS2 and AIF. By partitioning the full scan range into optimized windows, vDIA delivers enhanced sensitivity, selectivity, and throughput for comprehensive residue screening in complex matrices.

Reference

• Zhou Z., Jiang Z. Evaluation of Variable DIA for Non-target Screening of Veterinary Drugs in Animal Feed. Thermo Fisher Scientific Poster Note 64426, 2016.