Melamine in Infant Formula Sold in Canada: Occurrence and Risk Assessment

Abstract

An analytical method incorporating simple liquid extraction followed by mixed mode cation exchange/reversed phase solid phase extraction and liquid chromatography-tandem mass spectrometry was developed and validated for the analysis of melamine (MEL) in liquid and powdered infant formula. The method used two different MEL stable isotope labeled internal standards to monitor analyte recoveries and to account for matrix effects. The method is sensitive (limit of quantitation of 4 ng/g), accurate, and precise (during validation, recoveries corrected by internal recovery standard averaged between 92 and 104% for all fortification levels and matrices). The method was used to analyze 94 samples of infant formula purchased from major retailers in Ottawa, ON, Canada, to examine whether or not Canadian infants are exposed to background levels of MEL. MEL was detected in 71 of the 94 products analyzed at concentrations ranging from 4.31 to 346 ng/g (median = 16 ng/g). A comparison of estimated dietary exposures to the recently recommended World Health Organization toxicological reference value for melamine suggests that the presence of low levels of MEL in infant formula purchased in Canada does not represent a health risk.

Baseline levels of melamine in food items sold in Canada. II. Egg, soy, vegetable, fish and shrimp products

“…This variation in matrix effects amongst similar matrices has been noted before for infant formula (Tittlemier et al 2009) and animal feed (Heller and Nochetto 2008). The difference in amount of suppression between the two soy-based frozen desserts shown in Figure 1 emphasises the need to use stable isotope-labelled performance internal standards to correct for these matrix effects during mass spectrometric analyses; matrix-matched standards may be affected in a different manner than samples.…”

“…Low concentrations of MEL were detected in infant formula in Canada (Tittlemier et al 2009); concentrations ranged up to 0.346 mg/kg (median ¼ 0.016 mg/kg) in a survey of 94 Canadian infant formulae.…”

Synthesis and characterization of hapten-quantum dots bioconjugates: Application to development of a melamine fluorescentimmunoassay

“…involve typically the use of separation techniques, including capillary electrophoresis [7], high-performance liquid chromatography (HPLC) with spectrophotometric detectors [3,8], and liquid or gas chromatography-mass spectrometry [9,10]. Most of such already described methods offer low detection limits in the order of mg kg À 1 but often present some important disadvantages, including complex and time-consuming sample pretreatment, expensive instrumentation, long analysis times, etc.…”

Determination of Melamine and Derivatives in Foods by Liquid Chromatography Coupled to Atmospheric Pressure Chemical Ionization Mass Spectrometry and Diode Array Detection

“…P. O. Tang et al 2009;X. M. Xu et al 2009;Xia et al 2009;Zhao et al 2010;Tzing and Ding 2010;Lutter et al 2011;Koh et al 2011), liquid chromatography (LC) with ultraviolet detection or photodiode-array (DAD) (Bradley et al 2005;Ehling, Tefera, and Ho 2007;Kim et al 2008;Muñ iz-Valencia et al 2008;Zhong et al 2011;Chao et al 2011), and LC-MS (Andersen et al 2008;Lutter et al 2011;Filigenzi et al 2008;Cheng et al 2009;Desmarchelier et al 2009;Ibáñ ez, Sancho, and Hernández 2009;Karbiwnyk et al 2009;Tittlemier et al 2009;Wu et al 2009;Zhou et al 2009;Yu et al 2010;Tran et al 2010;Wu et al 2010;Zhang et al 2010;Jacob and Gamboa da Costa 2011;Han et al 2011;Goscinny et al 2011). Time-of-flight mass spectrometry (TOFMS) coupled to matrix assisted laser desorption ionization (MALDI) (Campbell, Wunschel, and Petersen 2007;Singh and Panchagnula 2011;Arnol et al 2011) or to direct analysis in real time (DART) (Vaclavik et al 2010) has been also used.…”