Interim Method for Determination of Melamine and Cyanuric Acid Residues In Foods using LC-MS/MS: Version 1.0
This procedure has been validated for the determination of melamine and cyanuric acid in both pork and fish tissue
using liquid chromatography with triple quadrupole tandem mass spectrometry (LC-MS/MS) The method has only
been evaluated for performance, but not fully validated, in infant formula. In this procedure, both cyanuric acid and
melamine are extracted from tissue and infant formula with a 50-50 acetonitrile-water extraction solution, followed
by centrifugation. The cleanup procedures for melamine involve mix mode cation exchange (MCX) solid phase
extraction (SPE) and that for cyanuric acid uses mix mode anion exchange (MAX) SPE. Consequently, aliquots of
the same extract are individually processed with the two modes of SPE. The final cleaned up extracts for both
melamine and cyanuric acid are in acetonitrile, making the procedure amenable to evaporate the excess solvent for
sensitivity needs or solvent exchange (depending on the LC column used). Each compound is analyzed separately
using a zwitterionic HILIC LC column. Electrospray ionization is used in both the negative ion (cyanuric acid) and
positive ion (melamine) modes. Two selected reaction monitoring (SRM) transitions are monitored for both
compounds. Commercially available, isotopically labeled internal standards for each compound were used to
correct for any matrix effects. The method limit of quantitation (LOQ) for melamine was: 25 μg/kg for tissue and
liquid formula and 200 μg/kg for dryinfant formula powder. The method LOQ for cyanuric acid was: 50 μg/kg for
tissue and liquid formula and 200 μg/kg for dry infant formula powder. Fortified test portions were within 75-125%
recovery. Determination of incurred residue in tissue agreed well with the results of an independent laboratory.
请点击此处下载
收藏
