VALIDATION OF MALONDIALDEHYDE AND 4-HYDROXY-2-TRANS-NONENAL MEASUREMENT IN PLASMA BY NICI-GC-MS

Measurement of the concentrations of aldehydes in biological samples h as become the object of much effort due to their relevance in relation to the toxic effects of lipid peroxidation, through which a number of aldehydes are derived. We have reconsidered a previously proposed met hod based on gas chromatographic mass spectrometric analysis of deriva tives obtained by the treatment of aldehydes with O-pentafluorobenzyl hydroxylamine followed by a trimethylsilylating agent. In view of the possible use of the method for the simultaneous evaluation of the plas ma levels of malondialdehyde and 4-hydroxy-2-trans-nonenal, we have st udied the linearity of the analysis using various internal standards, Commercially available, inexpensive 2,4-dihydroxybenzaldehyde gave opt imal results, the correlation coefficient of the calibration curve for plasma being r > 0.995 in the 0.1-5 mu M range for both the tested al dehydes. The between-day imprecision (%CV) and accuracy (%bias) Of the procedure determined using plasma samples spiked with the two aldehyd es and with an internal standard reached maximum values of 3 and 8%, a nd 5 and 12% for HNE and MDA, respectively, The results obtained on an alysis of plasma samples before and after oxidation with copper ions i ndicate the flexibility of the method for evaluation of the levels of MDA and HNE in plasma samples both under basal conditions and after an oxidative burst.