Table 4.
The comparison of results from the proficiency test by NRL-BM carried out using the UHPLC-HRMS/MS method and the HPLC-FLD Lawrence reference AOAC n. 2005.06 method.
| UHPLC-HRMS/MS Method | ||||
|---|---|---|---|---|
| PSP Toxin | CRM/01 (µg kg−1) |
CRM/02 (µg kg−1) |
CRM/03 (µg kg−1) |
Recovery (%) |
| STX | 23 ± 10 | <LOQ | <LOQ | 110 |
| GTX 1 | <LOQ | 208 ± 84 | <LOQ | 80 |
| GTX 4 | <LOQ | 69 ± 30 | <LOQ | 104 |
| GTX 1/4 (sum) | <LOQ | 274 ± 107 | <LOQ | 84 |
| GTX 2 | 318 ± 121 | 248 ± 98 | <LOQ | 96 |
| GTX 3 | 116 ± 51 | 91 ± 40 | <LOQ | 90 |
| GTX 2/3 (sum) | 433 ± 157 | 337 ± 127 | <LOQ | 94 |
| GTX 5 | 439 ± 159 | <LOQ | <LOQ | 87 |
| C 1/2 (sum) | 1203 ± 374 | <LOQ | <LOQ | 99 |
| STX equivalents1 | 363 ± 67 | 431 ± 156 | <LOQ | - |
| HPLC-FLD Lawrence Reference Method | ||||
| PSP Toxin |
CRM/01
(µg kg−1) |
CRM/02
(µg kg−1) |
CRM/03
(µg kg−1) |
Recovery (%) |
| STX | 25 ± 11 | <LOQ | <LOQ | 92.2 |
| GTX 1/4 (sum) | <LOQ | 544 ± 148 | <LOQ | 92.2 |
| GTX 2/3 (sum) | 345 ± 130 | 441± 133 | <LOQ | 85.7 |
| GTX 5 | 402 ± 148 | <LOQ | <LOQ | 96.9 |
| C 1/2 (sum) | 1078 ± 341 | <LOQ | <LOQ | 80.5 |
| STX equivalents | 400 ± 94 | 635 ± 217 | <LOQ | - |
The total concentrations are expressed as µg STXeq kg−1, corrected for recovery.