Analyzing for Melamine in Powdered Milk Products
Date of Award
Restricted Access Thesis
College of Theology, Arts, & Sciences
Math & Science
Dr. Tom Munson
In 2007 and 2008, there were some incidents in the United States and China having to do with melamine contamination in powdered milk products and pet food. Many pets and some infants died. The objectives of this study were: (1) to investigate why these incidents happened and to learn about the toxic health effects of melamine; (2) to adapt a published method for the trace-level analysis of melamine in powdered milk products for use in our laboratory; and (3), using this GC/MS method, to analyze various milk products for melamine. According to the FDA, the tolerable daily intake (TDI) of melamine is 2.5 ppm excluding infant formula and assuming that 50 % of the diet is contaminated by melamine. A published GC/MS selected ion monitoring (SIM) method for the analysis of melamine was adopted for use in our laboratory. The method involved sonication, absorption column, extraction, cleanup, and melamine derivatization followed by the GC/MS SIM analysis. Eleven different powdered products which were randomly chosen were analyzed using this GC/MS SIM method. Every sample was found to have possible melamine contamination likely from the analytical process, but far below the TDI. One sample initially appeared to contain about 2.0 ppm melamine but my further analysis of the data showed that result to be in error. The data from samples, however, do show some difficulty with regard to the measurement of the quantity of melamine present since the spike recoveries were considerably higher than 100 %. None of the milk products analyzed showed melamine contamination higher than 0.6 ppm even if all of the observed melamine were considered to have originated in the samples themselves rather than from analytical contamination. While this GC/MS SIM method performs adequately for determining whether milk product samples have melamine contamination near the TDI value of 2.5 ppm, to obtain valid information about melamine contamination at lower values, the method blank contamination would need to be made much lower and the problem with the high recoveries in the spiked samples would need to be solved.