LabChip GX/GXII User Manual

Introduction 20Principles of Operation (Continued)Quantitating the concentration and accurately sizing each fragmentare achieved by comparing against a sizing ladder and runninginternal standards or “markers” with each sample. Internalstandards of known concentration are mixed with the sample to aidin quantitation.The amount of sample sipped into the chip depends on pH, saltconcentration, and buffer additives. The internal standardsnormalize these factors so that the software can use the ratio of thearea of the curve of the standard to the unknown peak to determineconcentration directly. The internal standards lie slightly outside theassay range so they do not interfere with analysis.P/N 127170 Rev. 00 LabChip GX User Manual Caliper Life Sciences, Inc.