{'fraction_non_alphanumeric': 0.03411131059245961, 'fraction_numerical': 0.004488330341113106, 'mean_word_length': 5.798780487804878, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Oil Fingerprinting by Three-Dimensional (3D) Fluorescence Spectroscopy and Gas Chromatography–Mass Spectrometry (GC–MS)

Fingerprinting oil spills has become critical in assessing culpability for environmental damage. We analyzed nine commercial oil samples of five types (heavy diesel, crude oil, diesel, gasoline, and lubricant) via three dimensional (3D) fluorescence spectroscopy and gas chromatography–mass spectrometry (GC–MS). The 3D fluorescence spectra enabled classification of the nine oil samples into the five oil types, but the spectra were not useful in distinguishing oils of the same type. Similarly, total ion current polycyclic aromatic hydrocarbon (PAH) chromatography helped distinguish the oil samples with different properties, but it was not useful in differentiating oil samples with similar properties. We found that viewing the distribution patterns of 25 major PAHs was the best method to identify the different oil types and individual samples. Because weathering preferentially targets two-, three-, and four-ringed PAHs, five- and six-ringed PAHs are valuable fingerprinting markers.