Table 1.
Structure of a typical reference feature list. Each feature is specified by four required values and four optional values relating to its ion species. “Ion ID” is an integer that uniquely identifies a feature. Each feature belongs to a feature group (i.e., metabolite), which is specified in the column “Group ID”. All features with the same “Group ID” are different ions of the same metabolite. “Rt” is the retention time of the feature in minutes and “m/z” is its mass-to-charge ratio. The remaining columns are optional and used for the generation of differently formed ions if specified.
| Ion ID a | Group ID a | Rt a | m/z a | Ion Form b | Uncharged Ion Mass b | Ion Charge b | Ionisation Mode b |
|---|---|---|---|---|---|---|---|
| 1 | 1 | 2.78 | 160.075 | [M + H]+ | 159.068 | 1 | + |
| 2 | 1 | 2.78 | 177.102 | [M + NH4]+ | 159.068 | 1 | + |
| 3 | 2 | 3.19 | 482.296 | [M + NH4]+ | 464.262 | 1 | + |
| 4 | 3 | 3.27 | 330.458 | [M + NH4]+ | 312.424 | 1 | + |
a Mandatory information required by MetMatch; b optional information (used if provided)