Table 1.
Results of the spike experiments using cold-buffered chloroform-methanol extraction (CM5) as extraction method. The estimated concentration when the spiked amount (50 µM) is subtracted from the measurement is shown in brackets. The results are displayed as µMsample. The results are single injections of independent triplicates.
| Sample | Measured Concentration µMsample (measurement-spike) |
Average ± St. Dev. µMsample |
|---|---|---|
| Extracellular 1 (Oct 14) | 6.1 | 4.2 ± 2.8 |
| Extracellular 2 (Oct 14) | 2.2 | |
| Extracellular 3 (Oct 14) | N.D. | |
| Spiked extracellular 1 (Oct 14) | 61.1 (11.1) | 9.2 ± 2.1 1 |
| Spiked extracellular 2 (Oct 14) | 57.0 (7.0) | |
| Spiked extracellular 3 (Oct 14) | 59.5 (9.5) | |
| Intracellular 4 (Oct 14) | 35.9 | 31.2 ± 4.1 |
| Intracellular 5 (Oct 14) | 28.7 | |
| Intracellular 6 (Oct 14) | 28.9 | |
| Spiked intracellular 4 (Oct 14) | 94.4 (44.4) | 34.3 ± 9.0 1 |
| Spiked intracellular 5 (Oct 14) | 81.3 (31.3) | |
| Spiked intracellular 6 (Oct 14) | 77.2 (27.2) | |
| Total broth 4 (Oct 14) | 21.8 | 22.7 ± 1.3 |
| Total broth 5 (Oct 14) | 22.1 | |
| Total broth 6 (Oct 14) | 24.2 | |
| Spiked total broth 4 (Oct 14) | 77.8 (27.8) | 29.1 ± 6.5 1 |
| Spiked total broth 5 (Oct 14) | 73.3 (23.3) | |
| Spiked total broth 6 (Oct 14) | 86.2 (36.2) |
1 Average of estimated concentration (measured concentration–spiked amount).