ACS Publications:Simultaneous Determination of Post-Translational Racemization and Isomerization of N-Terminal Beta-Amyloid in Alzheimer's Brain Tissues by Covalent Chiral Deriv Simultaneous Determination of Post-Translational Racemization and Isomerization of N-Terminal Beta-Amyloid in Alzheimer's Brain Tissues by Covalent Chiral Deriv