y structure is a peptide chain of a sequence of amino acids of arginine- glycine-aspartic acid- tryptophan-proline-cysteine-mercaptopropionic acid linked together with amide linkage and disulphide bridge, the IR chart showing a very broad band at 3435.22 corresponding i think to N-H and OH stretch of amide group and carboxylic acids of amino acids and C-H stretch of alkane ,but the change that happened in the IR chart is the appearance of two broad strong bands at 1587.42 and 1398.36(less broad than the band at 1587) than the IR of the intact structure before oxidation, i first thought of oxidation of the disulphide bond to sulphoxide, sulphone or even sulphonic acid(unfortunately, i am not an organic chemistry expert, i just came with this problem during my research)but i looked at the IR frequencies table and found that the frequencies of sulphoxide at 1030-1070 cm-1, sulphone 1325 and 1140 cm and even sulphonic acid at 1345 and 1150 cm-1 so i excluded the oxidation of the disulphide bond as it shouldnot transmit at 1587cm-1 as i found in IR frequency tables, also there is a small shoulder at 1251 cm-1, so i thought about oxidation of N-H of amide groups to nitro containing derivatives as i found two strong broad band at 1587 &1399 cm-1 but of course didn't know is it possible under these conditions or not,lso i did LC-MS analysis of my oxidized product by LC-MS ESI, without fragmentation it gave m/z smaller than the m/z of the intact structure which suggeste certain cleavage of bonds but where and how ,i am still searching for the answer