Quantitative Chiroptical Sensing of Free Amino Acids, Biothiols, Amines, and Amino Alcohols with an Aryl Fluoride Probe

The
comprehensive determination of the
absolute configuration,
enantiomeric ratio, and total amount of standard amino acids by optical
methods adaptable to high-throughput screening with modern plate readers
has remained a major challenge to date. We now present a small-molecular
probe that smoothly reacts with amino acids and biothiols in aqueous
solution and thereby generates distinct chiroptical responses to accomplish
this task. The achiral sensor is readily available, inexpensive, and
suitable for chiroptical analysis of each of the 19 standard amino
acids, biothiols, aliphatic, and aromatic amines and amino alcohols.
The sensing method is operationally simple, and data collection and
processing are straightforward. The utility and practicality of the
assay are demonstrated with the accurate analysis of 10 aspartic acid
samples covering a wide concentration range and largely varying enantiomeric
compositions. Accurate er sensing of 85 scalemic
samples of Pro, Met, Cys, Ala, methylpyrrolidine, 1-(2-naphthyl)­amine,
and mixtures thereof is also presented.