We have shown that 1H NMR can serve as a suitable analytical tool for the assessment of relative amounts of d,l and meso HM-PAO isomers in a diastereomeric mixture and for the determination of the purity of either one of the two diastereomers alone. Therefore, we believe that this method will be useful for quality control in both academic and government regulatory laboratories as well as for radiopharmaceutical manufacturers. In addition, this analytical tool can provide rapid screening of possible suitable stereospecific reducing agents for the preferential formation of the d,l HM-PAO diastereomer without the necessity of completely working up the reduction reaction mixture.