A Matrix Of 3, 4-diaminobenzophenone For The Analysis Of Oligonucleotides By Matrix Assisted Laser Desorption Ionization Time Of Flight Mass Spectrometry

Having the advantages of high throughput, low detection limit and good tolerance to sample contamination, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has become a rapidly burgeoning field in recent years, and increasing efforts have been made to make it an effective tool in the analysis of nucleic acids.The matrix plays an essential role in MALDI analysis. However, there are few matrices that work well for oligonucleotides by far. Therefore, searching for new matrices is focused on to improve the MALDI performance. A new matrix of 3, 4-diaminobenzophenone (DABP) was demonstrated to be advantageous in the analysis of oligonucleotides by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. With DABP as a matrix, intact oligonucleotide ions can be readily produced with lower laser powers, resulting in better detection limits, less fragmentation and fewer alkali metal ion adducts compared with the results obtained with conventional matrices. Importantly, minimal fragmentation and fewer alkali metal ion adducts were seen even at low concentrations of oligonucleotides. It was also found that samples prepared with DABP are highly homogenous and therefore reducing the need for finding'sweet'spots in MALDI. In addition, excellent shot-to-shot reproducibility, resolution, and signal-to-noise ratio were seen with DABP as the matrix.DABP as a matrix was also applied to analyze mixtures of oligonucleotides, and the results were compared with that obtained by THAP and HPA. With DABP, a mixture of twelve oligonucleotides were well resolved with eight ion peaks located at their respective expected mass positions even when the mass difference was only 6 Da, while THAP and HPA couldn't work. DABP was also superior to THAP and HPA when a mixture of d (T)4,6,8,10,12 were analyzed.