PS-MS is a simple and powerful method for rapid ambient sample preparation. However, its simplicity also means separation of undesirable components (particulates and molecular interferents) is not possible. Furthermore, samples must be collected by other means (e.g., dried blood spot cards) and placed on the ticket in liquid form before analysis. Although the technique is sensitive (nanograms to tens of picograms LOD), it does not allow for enriching samples or removing undesirable components (particulates, molecular interferents, or reagents incompatible with mass-spectrometry, such as surfactants). Current designs place too much of a burden on the single substrate for sample collection, enrichment, and release to the analyzer. Often the optimal conditions for concentration and purification of an analyte on a substrate (i.e., the surface hydrophobicity and charge, matrix porosity, analyte solubility, and/or biochemical affinity) are conditions that are essentially opposite of the conditions optimal for solubilization and release of the analyte from the paper spray substrate to the MS analyzer. We propose to work with Prof. Charlie Mace at Tufts University to develop a set of PS-MS cartridges with integrated sampling and analyte enrichment. Three disposable cartridge styles are proposed, one for vapor/aerosol samples, one for environmental liquid samples, and one for biological fluids (blood or urine).
