The F-1-1-2-1 cluster was assigned to the hydrochloride and hydrobromide salts of hydrazine. These results are reasonable because the spectra were highly similar. The F-1-1-2-2-1 cluster exhibited a high spectral baseline match, low similarity in its chemical structure, and low similarity to all other spectra; however, some overlaps occurred. The F-1-1-2-2-2-1-2-2-1-1 cluster had no resemblance. Items with similar characteristics, such as a broad peak near 3500 cm -1 , were attributed to water and quaternary alkyl ammonium and classified, but not necessarily on adjacent branches. The F-1-1-2-2-2-1-2-2-1-2 cluster exhibited an expected broad carboxylic acid peak at approximately 1700 cm -1 ; however, other characteristic peaks were similar. It exhibited peaks corresponding to CH, NH, and C=O, and a chemical structure similar to that of the D cluster. However, the most significant difference is that it does not contain an aromatic group; therefore, the peaks in the fingerprint region were much weaker. The F-1-1-2-2-2-1-2-1 cluster exhibited a peak at approximately 3300 cm -1 corresponding to the NH group derived from the amide structure, a peak at approximately 1700 cm -1 corresponding to CO, and a peak at approximately 3000 cm -1 corresponding to CH. Compared with the D cluster, the peaks in the fingerprint area were simple for this cluster.