Barcodes are short base sequences that during library preparation are placed between the library key and the read. The barcode sequences provide a mechanism to distinguish and identify reads from different samplesduring data analysis.

The use of barcodes allows multiple samples to be sequenced together on one chip during a sequencing run, and still have the run's read data be analyzed separately afterward as distinct samples.

This diagram shows the placement of the barcode sequence, as well as the library key and adapters, with the read sequence (which is labeled "Template Bases"). The key is on the 5' end.

This example shows the location of the barcode sequence in both base space and flow space, using barcode IonPress_001 as an example: