Table 2.
LC-MS detection for conversion experiments of GTX2/3 to STX. Pure standard STX and GTX 2/3 were assayed by LC-MS before and after an L-cysteine conversion experiment. Conversion efficiency was determined by calculating intensities of the dominant ion (bold). Signature STX masses and retention time were observed following cysteine conversion of the pure GTX congeners, where they had previously not been present.
| PSP Congener | RT (min) | M+H | Fragment Ion | Reduction in Abundance |
|---|---|---|---|---|
| STX | 15.5 | 300 | 282 | |
| GTX 2 | 9.8 | 396 | 316 (298) | |
| GTX 3 | 10.8 | 396 | 316 (298) | |
| GTX 2 + L-cysteine | 9.8 | 396 | 316 | 80% |
| GTX 3 + L-cysteine | 10.8 | 396 | 316 | 71% |