Rapid analysis of alpha-dicarbonyl compounds by laser desorption/ionization mass spectrometry using 9-(3,4-diaminophenyl)acridine (DAA) as a reactive matrix.
A rapid, sensitive and selective method has been developed for the analysis of alpha-dicarbonyls using a readily ionizable compound, 9-(3,4-diaminophenyl)acridine (DAA), as a reactive matrix (derivatizing agent and ionization efficiency enhancer), by reactive matrix laser desorption/ionization time-of-flight mass spectrometry (RM-LDI-TOF MS). The reaction between the DAA and alpha-dicarbonyls resulted exclusively in formation of vacuum-stable dicarbonyl-quinoxaline acridine derivatives that were found to possess excellent ionization efficiency in positive ion mode, without the need to use an additional matrix. The alpha-dicarbonyls used as test compounds included methylglyoxal, dimethylglyoxal, and diphenylglyoxal. Both one-pot and rapid on-plate chemical modification approaches were employed with no extraction or purification necessary. The approach is particularly suitable for high-throughput analysis. The method was found to be selective and specific, with alpha-dicarbonyls unequivocally identified, even in complex matrices, e.g. beer. The figures of merit: relative standard deviation (RSD) 6.9-17%, (n = 4); limit of detection (LOD) < or =0.3 ng mL(-1) for the three standards tested using the one-pot derivatization method; and a good linear calibration curve using an internal standard derivatized in situ (R(2) > or = 0.979), demonstrate the applicability of the technique and its utility in improving the sensitivity and precision of the LDI analysis of small molecules.
Mugo
Samuel M
SM
Department of Chemistry, Memorial University of Newfoundland, St John's, NL, Canada.
Bottaro
Christina S
CS
D000166:Acridines / Q000737:chemistry*; D004785:Environmental Pollutants / Q000032:analysis / Q000737:chemistry; D005504:Food Analysis; D006037:Glyoxal / Q000032:analysis*; D007202:Indicators and Reagents; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
D000166:Acridines; D004785:Environmental Pollutants; D007202:Indicators and Reagents; D006037:Glyoxal