A Simple Cleanup Protocol Using a Novel SPE Device for UPLC-MS/MS Analysis of Multi-Residue Veterinary Drugs in Milk

Significance of the topic

Multi residue analysis of veterinary drugs in milk is critical for ensuring food safety and preventing health risks associated with drug residues in dairy products. Reliable detection methods support regulatory compliance and protect consumers from potential allergic reactions and antimicrobial resistance.

Objectives and study overview

This study aimed to develop a simple and rapid cleanup protocol using the novel Oasis PRiME HLB solid phase extraction (SPE) device combined with UPLC MS MS for simultaneous determination of 72 veterinary drugs across nine classes in milk samples.

Methodology

Sample preparation involved protein precipitation by mixing milk with acidified acetonitrile (4:1 ratio, 0.2% formic acid). The extract was cleaned via pass through SPE using the Oasis PRiME HLB cartridge to remove phospholipids and fats. After evaporation, samples were reconstituted in aqueous methanol and filtered before analysis.

Instrumentation

Results were obtained using an ACQUITY UPLC I Class system with BEH C18 column (2.1 x 100 mm, 1.7 µm) and a Xevo TQ S mass spectrometer operating in ESI positive and negative modes. Data acquisition utilized MassLynx v4.1 with Quanpedia database for method parameters.

Main results and discussion

Optimization of extraction conditions selected 0.2% formic acid in acetonitrile at a 4:1 ratio for effective protein precipitation without compromising recovery of basic analytes. The Oasis PRiME HLB cleanup significantly reduced phospholipid background compared to protein precipitation alone, extending instrument maintenance intervals. Method performance showed recoveries between 50% and 130% with RSD below 20% for all compounds at spiking levels from 0.1 to 10 µg/L, with minimal matrix effects.

Benefits and practical applications

The protocol offers a streamlined workflow for high throughput routine monitoring of veterinary drug residues in milk. It enhances sample cleanup efficiency, reduces instrument downtime, and simplifies method development by leveraging the Quanpedia database.

Future trends and potential applications

Emerging developments may include adaptation of PRiME SPE devices to other complex matrices, integration with automated sample handling, and expansion of compound libraries in databases to support broader multi residue analyses in food safety laboratories.

Conclusion

The described SPE cleanup combined with UPLC MS MS provides a robust, accurate, and efficient multi residue method for veterinary drug analysis in milk. Its simplicity and reliability make it suitable for routine food safety testing in laboratory environments.