Table 4.
Comparison of the number of the peaks extracted for the biological samples before and after trend filtering
| C18 | HILIC | |||||||
|---|---|---|---|---|---|---|---|---|
| Before filtering | Filtered | Before filtering | Filtered | |||||
| 1 | 2 | 1 | 2 | 1 | 2 | 1 | 2 | |
| Detected as standards (bp) | 34 | 13 | 5 | 5 | 366 | 22 | 32 | 15 |
| Detected as standards (rp) | 16 | 12 | 8 | 8 | 208 | 23 | 20 | 10 |
| Detected as contaminants (bp) | 59 | 20 | 3 | 2 | 254 | 28 | 10 | 8 |
| Detected as contaminants (rp) | 29 | 16 | 4 | 4 | 129 | 29 | 16 | 12 |
| Detected in ScoCyc (bp) | 97 | 25 | 4 | 4 | 639 | 78 | 28 | 24 |
| Detected in ScoCyc (rp) | 36 | 22 | 7 | 7 | 362 | 78 | 46 | 33 |
| Unidentified (bp) | 1235 | 19 | 4962 | 146 | ||||
| Unidentified (rp) | 632 | 123 | 3053 | 359 | ||||
The fraction of compounds with putative identifications is significantly increased after application of the trend filter
bp Labelled as base peaks by mzMatch software, rp labelled as derivative peaks, 1 number of peaks, 2 number of unique identifiers