Methyl malondialdehyde is not suitable as an internal standard for malondialdehyde detection in urine after derivatisation with 2,4-dinitrophenylhydrazine

A previously described method of measurement of malondialdehyde (MDA) in human urine after derivatisation with 2,4-dinitrophenylhydrazine (DNPH) was tested for a possibility of using methyl malondialdehyde (MeMDA) as an internal standard. Despite structural similarity, those compounds were found to produce different yields of derivatisation under the same conditions depending on urine matrix. We conclude, that MeMDA is not suitable as an internal standard for the measurement of MDA in urine under previously reported conditions when DNPH is used as a deriviatising agent.