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Ion distributions in the 38 mm cross section of a drift tube for ion mobility spectrometry were determined using a charge accumulation IonCCD with imaging capability of 2126 pixels each 21 μm wide. A 10 mCi 63Ni ion source with concentric cylinder geometry was examined experimentally using a drift tube with compressed rings separated by sapphire balls. Results were compared to computational findings from SIMION to learn the influence of source geometry on equipotential contours and on beam shapes. Swarms of ions formed in air at ambient pressure were shaped though field contours into ion beams which retained shape over the 45 mm drift length in an electric field of 30 V/mm. The IonCCD images revealed subtle beam alignments from azimuthal asymmetry of the source and holder not possible to see in a simple Faraday plate detector. Double slit experiments demonstrated a capability to shape ion beams with mechanical structures over a drift tube cross section.

A paper spray ion source was combined with a drift tube operating at ambient pressure for mobility measurements of ions derived from pharmaceutical solutions. Paper spray ionization with solvent alone resulted in a mixture of ions convolved to a single peak with a reduced mobility of 2.19 cm2/Vs in the mobility spectrum. These were mass-identified principally as m/z 157, (MeOH)2(HCOOH)2H+ and m/z 129, (MeOH)4(H2O)H+ while pharmaceuticals with nitrogen bases formed MH+ product ions. The duration of response was governed by the volume of liquid added to the paper source and was limited by evaporation of solvent in gas at 58 °C venting the drift tube. Quantitative variation was attributed in part to morphologic changes in the tip of the paper spray source. This was associated with mass flow in the electrical discharge and not due alone to cycles of wetting and drying of the paper. Mobility spectra of chlorpromazine in urine, exhibited a single product ion peak and linear response was 30 to 500 ng with an estimated limit of detection of 1.5 ng. Ion flux could be prolonged by continuous addition of liquid and findings portend a combination of paper spray ionization IMS with paper chromatography.