Shashank Jain

Date of Award


Degree Name

Master of Science



First Advisor

Dr. Andre R. Venter

Second Advisor

Dr. Sherine Obare

Third Advisor

Dr. Ramakrishna Guda

Access Setting

Masters Thesis-Campus Only


Methods for chemical surface analysis and characterization have undergone a remarkable advancement since the mid-20th century. Few methods exist for in situ analysis from intact surfaces. A new paradigm of in situ analysis, the ambient ionization mass spectrometry methods have recently become available which has completely reformed the field of surface analysis. Here, development and applications of a new surface sampling tool based on an ambient ionization mass spectrometry technique, Desorption Electrospray Ionization (DESI), is reported. This technique is called spray desorption collection (SDC). With SDC the analytes are collected onto an appropriately chosen second surface and can later be analyzed with a variety of suitable detection methods. Thus SDC decouples desorption and ionization steps in DESI and opens up many possibilities for the subsequent analysis of the sample. SDC was used to independently optimize desorption and ionization and it is shown that these two operations optimize to different parameter settings. The application of SDC to nanoparticle sampling and analysis is demonstrated. Development of a much improved prototype of SDC is presented which overcomes various limitations of the first generation SDC device and allows for large surface area sampling from across the entire plane of the sample surface. Application of this new device in the field of pharmaceutical cleaning validation is evaluated by comparing the results with traditional surface swabbing and cleaning validation methods.

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