# Library loading concentration considerations for the iSeq 100

On the iSeq 100 the loading volume for all library types is 20 µl.

| Library type                       | v2 Loading Concentration (pM) | v1 Loading Concentration\* (pM) |
| ---------------------------------- | ----------------------------- | ------------------------------- |
| 100% PhiX                          | 100                           | 60                              |
| AmpliSeq for Illumina Library PLUS | 50                            | 50                              |
| Illumina DNA Prep                  | 100                           | 200                             |
| Illumina DNA Prep with Enrichment  | 75                            | 100                             |
| Nextera XT DNA                     | 150                           | 50                              |
| TruSeq DNA Nano                    | 150                           | 100                             |
| TruSeq DNA PCR-Free                | 100                           | 100                             |
| Illumina DNA PCR-Free              | 120                           | N/A                             |

For other library types, 50 pM is the recommended starting loading concentration.

**Important note:** The above recommendations are general starting points. Optimize concentrations over subsequent runs to identify a loading concentration that consistently yields data that meets run specifications.

This information can be found in the [iSeq 100 System Guide](https://support.illumina.com/downloads/iseq-100-system-guide.html).

\*v1 reagents for the iSeq 100 have been discontinued, but the information for them remains here to assist labs still finishing their v1 inventory.

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| *For any feedback or questions regarding this article (Illumina Knowledge Article #2121), contact Illumina Technical Support* [*techsupport@illumina.com*](mailto:techsupport@illumina.com?subject=Question%2FFeedback%20Regarding%20Illumina%20Knowledge%20Article%20#000002121%20-%20Instrumentation%20\&body=Dear%20Illumina%20Technical%20Support,%0D%0A%0D%0A)*.* |


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