4-tert-Butylbenzaldehyde is an important intermediate for the synthesis of medicines, dyes, flavor and fragrance compounds. It is reported to be formed during the partial oxidation of 4-tert-butyltoluene by hydrogen peroxide in glacial acetic acid, catalyzed by bromide ions in combination with cobalt(II) acetate or cerium(III) acetate. Schiff base reaction between 4-tert-butylaniline and 4-tert-butylbenzaldehyde in ethanol has been carried out on-chip in the matrix assisted laser desorption ionization (MALDI) chamber, the formed imine was detected in real time.