Patent ID: 8101057

Claim:
A sample-manipulation method, comprising: (a) providing a channel device, the device including (i) an injection channel and a separation channel, each channel having a first end and a second end, with the separation channel intersecting the injection channel at a region between the ends of the injection channel; (ii) a first reservoir disposed for fluid communication with one of the ends of the injection channel; (iii) a first separation medium comprising a concentration of a first polymer held within the injection channel; and (iv) a second separation medium comprising a concentration of a second polymer held within the separation channel; wherein the concentration of the second polymer in the second separation medium differs from the concentration of the first polymer in the first separation medium; (b) introducing a sample, including a polynucleotide-analyte component and one or more contaminants, into the injection channel; (c) introducing a pH-modulating composition into the injection channel; (d) stacking the polynucleotide-analyte component under an injection voltage along the injection channel at a stacking region of the device defined by the intersection of the channels, and locating at least some of the one or more contaminants of the sample to a region between the stacking region and the second end of the injection channel; and (e) electrophoresing the polynucleotide-analyte component down at least a portion of the separation channel under a separation voltage along the separation channel, with at least most of said one or more contaminants remaining in the injection channel.