Analysis of low-abundance molecules in complex matrices by quadrupole-linear ion trap mass spectrometry using a...

Fast and sensitive analysis of low-abundance molecules in complex matrices has always been a challenge in chemical and biological applications. Mass spectrometry (MS) has been widely used in the fields of chemical and biological analysis due to its unparalleled specificity and sensitivity. However, the MS signals consistently deteriorate in the presence of matrices. Demands for more sensitive and efficient methods to analyze those low-abundance molecules in chemical and biological systems are in urgent need.

Based on a home-made quadrupole-linear ion trap (Q-LIT) mass spectrometer, a simultaneous fragmentation and accumulation strategy was developed to improve the sensitivity of the analysis for the low-abundance molecules in complex matrices. Ions were filtered by the quadrupole into the LIT. The precursor ions were fragmented and the product ions were isolated and accumulated in the LIT simultaneously. The fragmentation, isolation and accumulation processes were conducted at the same time. The accumulation time could be controlled to accumulate sufficient product ions.

With this strategy, the signal intensity of targeted molecules could be increased by 2-8 times and by increasing the accumulation time, this could be further enhanced. Those interferences induced by isomers and matrices can be reduced by using our method. We further applied our method to the quantification and analysis of biological samples. Tryptic digested peptides of myoglobin (Mb) were successfully detected by our method.

We have established a new method with great advantages in the detection of molecules in complex matrices. The application of this method promises better results in the bioanalytical area, especially for the analysis of substances in complex matrices in the future.