Application of ion mobility spectrometry for the detection of human urine

The aim of the present study was to evaluate the suitability of ion mobility spectrometry (IMS) for the detection of human urine as an indication of human presence during urban search and rescue operations in collapsed buildings. To this end, IMS with a radioactive ionization source and a multicapillary column was used to detect volatile organic compounds (VOCs) emitted from human urine. A study involving a group of 30 healthy volunteers resulted in the selection of seven volatile species, namely acetone, propanal, 3-methyl-2-butanone, 2-methylpropanal, 4-heptanone, 2-heptanone and octanal, which were detected in all samples. Additionally, a preliminary study on the permeation of urine volatiles through the materials surrounding the voids of collapsed buildings was performed. In this study, quartz sand was used as a representative imitating material. Four compounds, namely 3-methyl-2-butanone, octanal, acetone and 2-heptanone, were found to permeate through the sand layers during all experiments. Moreover, their permeation times were the shortest. Although IMS can be considered as a potential technique suitable for the detection, localization and monitoring of VOCs evolved from human urine, further investigation is necessary prior to selecting field chemical methods for the early location of trapped victims.