Fast Determination of Sodium Monofluoroacetate in Liquid Milk and Dairy Powder by Hydrophilic Interaction Liquid Chromatography-Triple Quadrupole Mass Spectrometry

Abstract

Manufactured sodium monofluoroacetate is a rodenticide with high acute toxicity. A fast and sensitive analytical method in liquid milk and dairy powder was developed both for routine analysis and for fast tackling the terrorist threat. Monofluoroacetate was extracted from liquid milk using acetonitrile and from dairy powder with water and acetonitrile, cleaned using a solid phase extraction (SPE) cleanup procedure with polymeric anion exchange (PAX) cartridge, and measured by hydrophilic interaction liquid chromatography-triple quadrupole mass spectrometry (LC-MS/MS). The conditions for the monofluoroacetate extraction, SPE cleanup, and instrument injection solvent were optimized. A BEH amide chromatographic column with hydrophilic interaction was used to directly separate monofluoroacetate under basic conditions. The limits of detection in liquid milk and dairy powder were 1 and 2 μg kg -1 , respectively. The recoveries at three spiking levels (10, 50, and 200 μg kg -1 ) were 72.5-97.6 % with relative standard deviations (RSDs) of 4.7-5.9 % for liquid milk and 70.1-92.8 % with RSDs of 4.7-6.8 % for dairy powder. The method has been applied to analyze sodium monofluoroacetate in dairy products including infant formula.

Analysis of Morpholinium Ionic Liquid Cations by Hydrophilic Interaction Columns Coupled with Indirect UV Detection

“…Moreover, compared with normal‐phase chromatography, the mobile phase of HILIC is compatible with mass spectrometry (MS) (especially electrospray ionization mass spectrometry), and thus, it improves the detection sensitivity . Thus, HILIC has been widely applied in various fields, including pharmaceutical analysis, food analysis, biomedical science, analytical chemistry, etc. In addition, many new stationary phases have been developed by introducing a variety of functional groups like hydrophilic macromolecules and ionic liquids, which can provide wider ranges of applications for HILIC …”