Overview
ISO 22186:2020 - "Milk and milk products - Determination of nitrofurazone" defines an LC–MS/MS laboratory method for the quantification of nitrofurazone residues in milk and milk products. The method uses a QuEChERS-based extraction, isotopic dilution with a labelled internal standard (13C15N‑nitrofurazone), and analysis by liquid chromatography tandem mass spectrometry in scheduled MRM with negative electrospray ionization. It has been validated to measure intact nitrofurazone at trace levels down to 1 ng/g in fluid milk and powdered dairy products (whole-product basis). Application to other dairy matrices is possible but requires additional validation.
Key topics and technical requirements
- Analytical principle: QuEChERS extraction (per EN 15662:2018 with modifications) followed by dispersive SPE clean-up and LC–MS/MS quantification.
- Internal standard: Isotopic dilution using 13C15N‑nitrofurazone for accurate quantification.
- Calibration options: External calibration or matrix‑matched calibration curves are both permitted.
- Identification/confirmation: Follows confirmation criteria referenced from EU Commission Decision 2002/657/EC (ion ratios, retention time, etc.).
- Validated performance: Sensitivity demonstrated to 1 ng/g in fluid milk and powdered dairy products; precision and reproducibility data are included.
- Sample prep essentials: Reconstitution of powders, spiking with internal standard, acetonitrile extraction, partitioning with MgSO4/NaCl, d‑SPE cleanup using MgSO4/PSA/C18, evaporation and reconstitution in methanol prior to LC–MS/MS.
- Quality control: Reagent blanks, positive quality controls, and matrix‑matched calibration samples are specified to ensure method integrity.
Applications and who should use it
- Food safety laboratories performing routine residue monitoring for nitrofurazone in milk and dairy products.
- Regulatory agencies and control authorities enforcing prohibitions on nitrofurazone use in food‑producing animals.
- Dairy industry quality assurance teams needing validated methods for supplier testing and internal compliance.
- Contract testing laboratories offering trace analysis and confirmatory testing for veterinary drug residues.
Practical benefits include high specificity and trace‑level detection suitable for regulatory compliance and consumer safety assessments.
Related standards
- EN 15662:2018 - QuEChERS method referenced for extraction protocol (with modifications).
- EU Commission Decision 2002/657/EC - criteria for identification and confirmation in mass spectrometric residue analysis.
Keywords: ISO 22186, nitrofurazone, milk and milk products, LC‑MS/MS, QuEChERS, dairy testing, trace analysis, isotopic dilution, matrix‑matched calibration, residue monitoring.