Figure 1.
Figure 2.
UHPLC gradient program for the separation of taurine_
| Time (min) | Flow (mL/min) | Mobile phase A (%) | Mobile phase B (%) |
|---|---|---|---|
| Initial | 0.5 | 99 | 1 |
| 0.7 | 0.5 | 99 | 1 |
| 1.3 | 0.5 | 87 | 13 |
| 3.7 | 0.5 | 85 | 15 |
| 7 | 0.5 | 60 | 40 |
| 8 | 0.5 | 5 | 95 |
| 9 | 0.5 | 5 | 95 |
| 9.8 | 0.5 | 99 | 1 |
| 10.5 | 0.5 | 99 | 1 |
Recovery of taurine tested at three concentration levels (10, 100, and 500 μmol/L)_
| Taurine | |||
|---|---|---|---|
| Added (μmol/L) | 10 | 100 | 500 |
| Found (μmol/L) | 10.80 | 91.50 | 532.70 |
| RSD (%), n = 5 | 0.8 | 2.7 | 0.6 |
| Recovery (%) | 108.0 | 91.5 | 106.5 |
Evaluation of accuracy parameters of taurine tested at three concentration levels (10, 100, and 500 μmol/L)_
| Nominal (μmol/L) | Found (μmol/L) | RSD (%) | RE (%) | |
|---|---|---|---|---|
| Intra-day, n = 5 | 10 | 10.92 | 2.62 | 9.2 |
| 100 | 90.99 | 0.10 | −9.0 | |
| 500 | 533.94 | 0.72 | 6.8 | |
| Inter-day, n = 10 | 10 | 10.95 | 3.95 | 9.5 |
| 100 | 92.31 | 0.57 | −7.7 | |
| 500 | 535.30 | 1.41 | 7.1 |
Determined concentration of taurine in four tested commercial available energy drinks_
| Beverage | Parameters | |||
|---|---|---|---|---|
| Found ± SD (mg/mL) | RSD (%), n = 3 | Declared (mg/mL) | % of declared content | |
| Red Bull | 2.80 ± 0.07 | 2.6 | 4 | 70.0 |
| Hell | 3.77 ± 0.05 | 1.4 | 4 | 94.5 |
| Tiger | 3.78 ± 0.01 | 0.1 | 4 | 91.8 |
| Maxx | 3.67 ± 0.03 | 0.9 | 4 | 94.3 |
Overview of several selected operation and validation parameters of the UHPLC-MS method_
| Taurine | |
|---|---|
| tR (min) | 1.96 |
| a (counts) | 0.00642644 |
| RSDa (%), n = 6 | 9.7 |
| b (counts × μmol−1 × L) | 0.00801683 |
| RSDb (%), n = 6 | 4.8 |
| r2 | 0.9982 |
| Linear range (μmol/L) | 10–500 |
| LOD (μmol/L) | 4.29 |
| LOQ (μmol/L) | 10 |
| N | 93,340 |