File Format Overview

An mzTab-M file is a UTF-8 plain-text, tab-delimited file. Each line begins with a section prefix, followed by tab-separated fields. Comment lines begin with # and are ignored by parsers.

For the complete field-level specification, see mzTab-M 2.1 Specification.

Metadata Section (MTD)

The metadata section opens the file and defines all controlled vocabulary terms, software, databases, assays, and study variables that are referenced in the data tables. All mandatory MTD fields must appear before any data rows.

Key mandatory fields include mzTab-version, mzTab-mode, mzTab-type, and description.

Small Molecule Summary (SML)

The SML section contains one row per reported small molecule entity. Each row aggregates evidence across all features and all assays.

Columns include identifiers (chemical_name, inchi, smiles), database cross-references, and abundance values per assay.

Small Molecule Feature (SMF)

The SMF section captures individual detected features — retention time, m/z, charge, and adduct — and links them to the SML summary row via SMF_ID.

Including SMF rows is strongly recommended so that downstream consumers can access the underlying signal evidence.

Small Molecule Evidence (SME)

The SME section records each individual identification evidence entry and links it to SMF rows. It captures the database match, identification method (MS1 or MS2), rank, and associated scores.

Line Endings and Encoding

Files MUST use UTF-8 encoding. Line endings MUST be LF (\n); CRLF is not permitted. Tabs are the sole column delimiter; no quoting of fields is used.