Development of a pair of differential H/D isotope-coded derivatization reagents d0/d3-4-(1-methyl-1H-phenanthro[9,10-d]imidazol-2-yl)phenlamine and its application for determination of aldehydes in selected aquatic products by liquid chromatography–tandem

A new pair of derivatization reagents, d0-4-(1-methyl-1H-phenanthro[9,10-d]imidazol-2-yl)phenlamine (d0-MPIA) and d3-4-(1-methyl-1H-phenanthro[9,10-d]imidazol-2-yl)phenlamine (d3-MPIA) have been designed and synthesized. It was successfully used to label aliphatic aldehydes and the aldehyde derivatives were analyzed by high-performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS). The new isotope-coded reagents could easily label aldehydes under acidic conditions in the presence of NaCNBH3. The target derivatives exhibited intense [M+H]+ and regular product ions with electrospray ionization source in positive mode. The d0/d3-MPIA-aldehydes were monitored by the transitions of [M+H]+→m/z 322 and [M+H]+→m/z 165, and the obtained detection limits were in the range of 0.18–15.9 pg/mL at signal to noise ratio of 3. The global isotope internal standard technology was employed for quantification analysis with d3-MPIA-aldehyde as internal standard for corresponding d0-MPIA-aldehyde. Excellent linear responses for relative quantification were observed in the range of 1/10–10/1 with coefficients >0.998. The developed method has been applied to the quantification of aliphatic aldehydes in selected aquatic products with RSD<3.6% and recoveries >85.2%.