In this Thesis work, we studied Chromon derivatives by Bruker micrOTOF -Q ESI-TOF/APCI TOF and mainly APCI in Tandem mode, because for the more informative fragmentation studies usually the protonated molecules (adduct ions) should have been generated, but in case of chromon derivatives it was not possible under ESI ionization conditions, so we used APCI instead. All the samples were discussed, and only unique results were mentioned -to eliminate repetition- in fragmentation stability, and identification as in sample 4 double batches. First, we started with the normal MS mode to check the purity and molecular weight accuracy of each molecule and compared the different batches of each sample, all the samples were almost accurate with +/- 0.004 m/z units tolerance, and we used Isotope pattern software as a reference. After that we used the Tandem MS for complete all tasks, in fragmentation the results were very satisfying and the MS spectrum was interpreted in a logical way, where bond cleavage and mechanism were taken into consideration. I faced some impurities, such peaks were impurities of the ionizer itself as prior experiments were done before our experiments, like in samples 2 and 3 and those peaks were indicated ad explained above. In sample 2 only, a negative ion was used due to the poor fragmentation in the positive mode. For the identification of sample 4, 2 batches were compared and there was a 15.994 m/z difference, and after investigation, it turned out that the C-3 has a bond with a phenyl group while the other batch was the Phenoxy group. And in checking the fragmentation stability of the different molecules, after checking the Survival yield curve, I started to calculate the Characteristic collision energy which gives 50% of the fragmentation yield, but in the case of the chromon derivatives, the molecular weight varies significantly so the comparison will not be accurate, so a correction factor was used and sample 1 has been taken as a reference, finally, the samples were ordered based on their fragmentation stability as following: 1 > 5 > 4 > 2 > 3. All the analysis was done by using DataAnalysis 3.4 and IsotopePattern provided by Bruker