Keep the preprint and the published article as two separate Zotero items and record the relationship between them; merging them as duplicates erases the publication stage you need to cite. Zotero's duplicate detection flags items it considers potential duplicates and offers a merge interface that combines item records while preserving collections and tags, so a merge collapses the two stages into one entry.
Confirm the publication status first
Compare the two items using deposited metadata. A DOI lookup through the Crossref REST API returns the metadata deposited for that DOI, which helps you see whether one record carries a journal article's deposited details and the other does not. For life-science papers, the NIH Preprint Pilot labels eligible preprints in PMC and PubMed as preprints so readers can distinguish publication status; that label is a direct signal of stage.
Keep the pair distinct
- Check each item's metadata for a publication-status signal, such as a preprint label or a DOI with deposited journal metadata. Expected result: you can name which record is the preprint and which is the published article.
- If Zotero flags the pair as potential duplicates, decline the merge and keep both items. Expected result: each publication stage stays in your library as its own record.
- Record the relationship in the item metadata, for example by noting the other version's identifier in a note or field. Expected result: a reader of your library can trace the preprint to its published version.
When merging is appropriate
Reserve the merge interface for records that describe the same version of the same work, where combining collections and tags loses nothing about publication stage. When the two items differ in stage, the pair itself is the deliverable.