The construction of the devices, and the resulting application of the sample and reagents to the chromatographic medium through {HEAD ~ a barrier} in an aperture, allows more even application of the samples and reagents to {TAIL ~ the chromatographic medium}, and reduces interference that might otherwise be introduced by particulates or colored samples 
The construction of the devices , and the resulting application of the sample and reagents to the chromatographic medium through { HEAD ~ a barrier } in an aperture , allows more even application of the samples and reagents to { TAIL ~ the chromatographic medium } , and reduces interference that might otherwise be introduced by particulates or colored samples
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