{'fraction_non_alphanumeric': 0.03671328671328671, 'fraction_numerical': 0.013111888111888112, 'mean_word_length': 4.963541666666667, '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}}
Use of humidified air in optimizing APCI-MS response in breath analysis.

An atmospheric-pressure chemical ionization-mass spectrometer (APCI-MS) system was modified to introduce gaseous samples as well as to humidify sheath and auxiliary gases. Solutions of single odorants in pentane were evaporated inside a vessel in a dry environment (relative humidity 0-10%) and in a human-breath-like environment (relative humidity 88-98%) and subsequently analyzed in the positive ion mode. The results indicated that using dry nitrogen as sheath and auxiliary gases led to strong fragmentation of the molecules combined with a low sensitivity of detection. Humidification of both gases not only increased sensitivity but also resulted in the protonated molecular ion as the base peak in 5 of the 6 compounds studied (ethyl butyrate, 3-methyl-3-phenyl glycidic acid ethyl ester, gamma-decalactone, (E)-2-hexenal, and cinnamic aldehyde). Only hexanal, which formed a cluster (m/z 183), did not have the protonated molecular ion as base peak. It was found that the humidity of the sample itself did not have any influence on sensitivity or fragmentation.