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Supporting Information:
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Quantitative surface scanning by Direct Analysis
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in Real Time mass spectrometry
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Tim T. Häbe1and Gertrud E. Morlock1*
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Science, Justus Liebig University Giessen, Heinrich-Buff-Ring 26-32, 35392 Giessen, Ger-
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Interdisciplinary Research Center (IFZ) and Institute of Nutritional Science, Chair of Food
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Running title: Quantitative HPTLC-DART-MS surface analysis
Keywords: DART, ambient ionization, surface analysis, HPTLC, planar chromatography
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* Correspondence to: Gertrud E. Morlock, Justus Liebig University Giessen, Heinrich-Buff-
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Ring 26-32, 35392 Giessen, Germany. E-mail: Gertrud.Morlock@ernaehrung.uni-giessen.de
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Figure S-1. Standard ceramic DART cap (ID 2.54 mm, a) and optimized one with a pro-
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longed cone and reduced ID of 1.00 mm (b); standard transfer tube (c) and optimized one
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with angeled edge (d).
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Figure S-2. Vertical stabilization using an aligned hexagon cap nut (a) in front of the transfer
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tube (b) reduced height deviations of the HPTLC plate (c) mounted on the plate carrier in
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standby position (d).
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Figure S-3. Scheme of the gas stream scattering after contact with the impact area on the
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substrate using the standard DART SVPA set-up (a; horizontal carrier, 40° angled ion source,
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and standard transfer tube) versus optimized configuration (b; 20° angled carrier, 60° angled
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ion source, and modified transfer tube).
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Table S-1. Repeatability study of the application procedure for 10 deposited BE bands, each
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900 ng/band; for prefocused BE in a substance range of 10–900 ng/band; both evaluations
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were performed by digital image evaluation. After chromatography and DART-MS, the mean
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recovery and repeatability were determined via EIC areas using the 360 ng/band of the ME
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and BE standard for calculation.
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