A variety of non-proximate mass spectrometry techniques have been implemented to sample organic analytes from distant surfaces, but they frequently risk signal carryover and loss by relying on unheated plastic tubing to transfer analytes back to the instrumentation. Non-proximate desorption photoionization (NPDPI) has used heated and passivated stainless steel transfer tubing since its inception, allowing clean but painstaking analysis of large objects. A unique new design based on gooseneck tubing confers flexibility comparable to that of plastic but resists organic molecule loss to the transfer tube wall. An integrated desorption probe based on a heated gas jet is constructed around the non-proximate terminal for easy manual operation in conjunction with a hand-held controller. Real-time probe analysis is demonstrated on typically inaccessible surface geometries, using a bottom surface contact sensor and side-contact piezo sensors to aid the user in optimally positioning the probe when it cannot be seen. Neutrally desorbed, the gas-phase analyte is efficiently transferred up to 4 m to the doped photoionization source. Involatile and volatile analytes are observed from commonplace objects that have narrow dimensions, blind concave surfaces, and low weights that cannot be forcefully pressed by the probe contact.
G. Asher Newsome (Thu,) studied this question.