Computer Vision-Assisted\nRobotized Sampling of Volatile\nOrganic Compounds

In conventional chemical analysis, samples are homogenized,\nextracted,\npurified, and injected into an analytical instrument manually or with\na certain degree of automation. Such complex methods can provide superior\nperformance in terms of sensitivity or selectivity. However, in some\ncases, it would be advantageous to possess a method that circumvents\nthose preparatory steps, which require much attention. Here, we present\na facile analytical approach to sampling volatile organic compounds\n(VOCs). Solid specimens emitting VOCs can be dropped onto the drop-off\nzone at a random position without any special alignment. A computer\nvision system recognizes specimen position, and a robotic arm places\na sampling probe in the proximity of the specimen. The probe aspirates\nthe VOCsemitted by the specimenwith the aid of a suction\nforce. A portion of the gaseous extract is transferred to the tritium-based\nion source of a drift-tube ion mobility spectrometer. The ion mobility\nspectrum is immediately displayed in the customized graphical user\ninterface (GUI). The sampling system also features a function for\nflushing extract ducts with hot nitrogen gas. Multiple specimens can\nbe dropped for analysis at the same time. In one embodiment, the system\ncan distinguish fresh meat from spoiled meat. When two meat specimens\nare placed on the drop-off zone, they are immediately sampled by the\nrobotic arm, analyzed, and labeled on the digital image displayed\non the GUI. Thus, the developed autosampling platform provides a hassle-free\nway of qualitative or semiquantitative analysis of raw specimens.