We next applied the approach to a third class of compoundsamino acids. Mixture C contained L-Glutamic acid (17 , Supplementary Information). We selected 1401 crystals for autonomous MicroED analyses and this time the success rate was even higher than for Mixture B as 1121 out of 1401 (80%) crystals were identified. The areacorrected ratios of compounds in mixture C were found to be similar to the ratios obtained by counting the number of crystals, with most ratios within 2% in relative amounts. However, for L-Tyrosine, L-Aspartic acid, and L-Glutamine, which had larger relative errors, the area corrected ratios tended to be better than the uncorrected ones, particularly for L-Tyrosine, where the overestimated ratio dropped from 10.6% to 8.2% after area correction. The estimated ratios are surprisingly close to the weighed-in ratios in this analysis (Figure ; Table in Supplementary Information). These results suggest that sample preparation and the material used for grid preparation are the key determinants of success. It is also possible that the amorphous carbon support used in these experiments is more suitable for biological material like amino acids.