An effective 15N-and deuterium (D)-labeled 2, 6-bis (oxazolin-2-yl) pyridine (pybox)–La complex based probe ionization method that produces a distinct isotopic shift was developed. The distinct isotopic shift was detected by using the newly synthesized 15N-D- labeled pybox complexes. Moreover, O-[3-(tetramethylpybox)-propyl]-hydroxylamine (oxime– TMpybox) was prepared for attachment to the carbonyl group of the target molecule. ...