title: Detection of melamine in infant formula and grain powder by surface-assisted laser desorption/ionization mass spectrometry.
abstract: We have developed a method for the determination of melamine (MEL), ammeline (AMN), and ammelide (AMD) by surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS) using gold nanoparticles (Au NPs). The major peaks for MEL, AMN, and AMD at m/z 127.07, 128.05, and 129.04 are assigned to the [MEL + H](+), [AMN + H](+), and [AMD + H](+) ions. Because the three tested compounds adsorb weakly onto the surfaces of the Au NPs through Au-N bonding, they can be easily concentrated from complex samples by applying a simple trapping/centrifugation process. The SALDI-MS method provides limits of detection of 5, 10, and 300 nM for MEL, AMN, and AMD, respectively, at a signal-to-noise ratio of 3. The signal variation for 150-shot average spectra of the three analytes within the same spot was 15%, and the batch-to-batch variation was 20%. We have validated the practicality of this approach by the analysis of these three analytes in infant formula and grain powder. This simple and rapid SALDI-MS approach holds great potential for screening of MEL in foods.
authors.affiliation: Department of Chemistry, National Taiwan University, Taipei, Taiwan.
authors.forename: Yi-Ting
authors.initials: YT
authors.lastname: Hsieh
authors.forename: Wen-Tsen
authors.initials: WT
authors.lastname: Chen
authors.forename: Iva
authors.initials: I
authors.lastname: Tomalová
authors.forename: Jan
authors.initials: J
authors.lastname: Preisler
authors.forename: Huan-Tsung
authors.initials: HT
authors.lastname: Chang
mesh_terms: D019343:Citric Acid; D002523:Edible Grain; D005433:Flour / Q000032:analysis*; D006046:Gold / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D041943:Infant Formula / Q000737:chemistry*; D057230:Limit of Detection; D053768:Metal Nanoparticles / Q000737:chemistry; D000644:Quaternary Ammonium Compounds; D015203:Reproducibility of Results; D059629:Signal-To-Noise Ratio; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D014227:Triazines / Q000032:analysis*
chemical_list: D000644:Quaternary Ammonium Compounds; D014227:Triazines; D019343:Citric Acid; D006046:Gold; C481046:ammonium citrate; C067139:ammelide; C000089:ammeline; C011907:melamine