Fast quantitative determination of melamine and its derivatives by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry

Abstract

A simple, sensitive and fast method for the determination of melamine and its derivatives in milk powder using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) was developed. Neither time-consuming sample preparation, nor special target plates, or other extra equipment are necessary. The common matrix sinapinic acid (SA) was used with a dried-droplet preparation. Detection limits (signal-to-noise (S/N) ratio = 3) for standard solutions of melamine, ammeline and cyanuric acid were 10, 25 and 10 µg/L, respectively. The limit of quantification (LOQ) for melamine was 25 µg/L and excellent linearity (R(2): 0.9990) was maintained over the range of 10-2000 µg/L. Ammeline and cyanuric acid were analyzed with an LOQ of 50 µg/L and also excellent linearity (R(2): 0.9997 and R(2): 0.9998). Good accuracy and precision were obtained for all concentrations within the range of the standard curve. The developed method was successfully used for the determination of melamine, ammeline and cyanuric acid in milk powder samples with a simple sample preparation. The LOQ of melamine was 0.5 µg/g. Ammeline and cyanuric acid were detectable at 0.5 and 5 µg/g. This method showed excellent accuracy, precision and linearity and significantly reduces the needed analysis time, as only approximately 10 s/sample measuring time is required. To the authors' knowledge, this is the first published method to quantify melamine and derivatives by MALDI-TOF-MS.

Quantification of Antibiotic in Biofilm-Inhibiting Multilayers by 7.87 eV Laser Desorption Postionization MS Imaging

“…3,4,32 By contrast, LDPI-MS is only observed here to display 0.3 nanomole sensitivity (LOD). However, this comparison is premature given that commercial MALDI-MS instruments benefited from two decades of development while the LDPI-MS instrument utilized here is a home-built, noncommercial prototype.…”

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

“…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. However, most procedures are concerned with the determination of MEL or mixtures of MEL and CA in different matrices but do not tackle with all the mentioned species.…”

Determination of copper and lead in tequila by conventional matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry and partial least squares regression

“…To counterbalance these limitations, a range of matrix‐free laser desorption/ionization techniques have been developed; however, the efficiency of analyte desorption/ionization strongly depends on the chemical nature and the size of nanomaterial applied to assist the process, and poorer sensitivity has often been reported in these new techniques as compared with conventional MALDI with organic matrices . In another approach for enhanced determination of small molecules, a considerable effort has been dedicated to the improvement of sample preparation and on the selection of instrumental conditions in conventional MALDI thus avoiding undesired matrix effects …”