User:Jonathan Cline/Notebook/Melaminometer/Current Practices of Detection

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A rapid method for the detection of melamine in infant formula and liquid milk meets the requirements of China’s Ministry of Science and Technology (MOST), claims its developer.
Waters Corporation said its liquid chromatography combined with tandem quadruple mass spectrometry (UPLC/MS/MS) method was originally developed in response to requests from China for a method of analysis to address the challenges of detecting melamine in milk products.
Dr Paul Young, senior manager, Chemical Analysis Operations, Waters Corporation said that the new approach compares favourably with the Gas Chromatography Mass Spectrometry (GC/MS) method, employed by many laboratories for detection of melamine, as well as another conventional analysis tool, high performance liquid chromatography (HPLC).
“The UPLC/MS/MS method requires no derivatization step and with retention time of less than two minutes will complete the instrumental analysis inside four minutes," explained Young.
He said, in contrast, a GCMS based method requires a derivatization reaction time typically in the range 45 to 120 minutes, followed by an analysis time of around 20 minutes per sample, while the HPLC based methods need 10 to 15 minutes.
He said the UPLC/MS/MS method can detect melamine contamination as low as 1 μg/Kg (ppb).
  • High-performance liquid chromatographic method for the simultaneous detection of the adulteration of cereal flours with melamine and related triazine by-products ammeline, ammelide, and cyanuric acid. Food Addit Contam. 2007 Dec;24(12):1319-25.
Melamine has been used for the adulteration of cereal flours in order to increase their apparent protein content. Crude melamine may contain several by-products, i.e. ammeline, ammelide, and cyanuric acid. The simultaneous analysis of all four chemicals is difficult because of the formation of an insoluble salt between melamine and cyanuric acid. A simple and convenient high-performance liquid chromatography (HPLC) method for the detection of the adulteration of cereal flours with all four chemicals is proposed herein. The precipitate formation between melamine and cyanuric acid was prevented by using alkaline conditions (pH 11-12) for both standards preparation and sample extraction. The method uses matrix-matching, which involves the construction of a calibration curve on a blank (negative control) matrix, which is then used for the quantitation of melamine and by-products in adulterated (positive) samples. Matrix-matching compensates for analyte losses during sample preparation, and for matrix effects. The method was successfully applied to wheat, corn, and rice flours, and is expected to be applicable (with some modifications) to soy flour as well. The method allows for the detection of melamine, ammeline, and ammelide at approximately 5 µg g-1, and cyanuric acid at approximately 90 µg g-1 in wheat flour.
  • [Full Text] GC-MS Screen for the Presence of Melamine, Ammeline, Ammelide and Cyanuric Acid (Version 2.1). U.S. FDA May 22, 2007 10:36 AM ET
This procedure was developed by PRLNW and FCC to screen various matrices for the presence of melamine and some related compounds at the established minimum reporting level (MRL) of 10 µg/g and above using gas chromatography/mass spectrometry. Samples are extracted using a mixture of acetonitrile/water/diethylamine and the analytes are subsequently converted to trimethylsilyl derivatives for analysis.
  • [Full Text] Determination of Melamine and Cyanuric Acid Residues in Infant Formula using LC-MS/MS. U.S. FDA Laboratory Information Bulletin LIB No. 4421 Volume 24, October 2008
This method consists of an initial extraction with 2.5% aqueous formic acid, followed by a series of filtration, centrifugation, and dilution steps. Both compounds are analyzed in the same chromatographic program using a zwitterionic HILIC LC column. Electrospray ionization is used in both the negative ion (CYA) and positive ion (MEL) modes. Two selected reaction monitoring (SRM) transitions are monitored for both compounds. The amount of compounds present is determined with a calibration curve consisting of sample extracts from infant formula fortified from 0.25 to 5 µg/g that have been taken through the extraction procedure. The range of recovery from fortified infant samples (n =38) was 70-114 % (RSDs 4.5- 22.7 %), and 72-110% (RSDs 5.7-24.9%) for cyanuric acid and melamine, respectively. The limits of quantification and confirmation are 0.25 µg/g for both analytes in dry infant formula.
MDS Analytical Technologies, a leader in innovative solutions for drug discovery and life-sciences research, today announced that the Abraxis Melamine Detection Kit has been validated for use on MDS Analytical Technologies' SpectraMax® absorbance microplate readers with SoftMax® Pro 5 GxP analytical software, an industry-standard analysis software for FDA 21 CFR Part 11 compliance.
This solution from MDS Analytical Technologies offers a cost-effective, high-throughput, quality-assurance solution to detect melamine contamination in such food products as milk, infant formula, pet food, and confectionery.
Melamine, an organic industrial polymer, has recently been found in various foods and, if undetected, may cause serious illness or death. This enzyme-linked immuno-sorbent assay (ELISA) solution will enable quality-assurance technicians in food-safety laboratories to easily detect the presence of melamine down to 10 parts per billion (ppb).
"Recent stories of melamine-related illnesses and deaths have made melamine contamination a serious concern," said Andy Boorn, President of MDS Analytical Technologies. "The pre-programmed melamine protocol in SoftMax Pro 5 GxP software, combined with our microplate readers, enables us to offer a more-complete high-throughput solution to better address what has become an increasingly important consumer safety issue."
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