Table 12.
Experimental data for the evaluation of cross-interferences by using the standard addition method. V1b, VDQ and VPQ are the added volumes of the standard methanol solutions of [1b] = 2500 μg L−1, [DQ] = 3000 μg L−1 and [PQ] = 1500 μg L−1, respectively. VPQ-spike and VDQ-spike are the volumes added to a tap water sample to spike it at the concentration of 6.0 μg L−1. This value was normalized to the total volume of 2500 μL, 60/40 methanol/water. The sample was divided into 10 aliquots.
| Entry | Vsample, μL | V1b, μL |
VPQ-spike, μL |
VDQ-spike, μL | VDQ, μL | VTOT, μL | [1b], μg L−1 | [PQ]spike, μg L−1 | [DQ]spike, μg L−1 | [DQ], μg L−1 | ΔF * |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 0 | 1000 | 30 | 0 | 0 | 0 | 2500 | 30.0 | 0.0 | 0.0 | 0.0 | 0.0 |
| 1 | 1000 | 30 | 10 | 5 | 0 | 2500 | 30.0 | 6.0 | 6.0 | 0.0 | 17.9 |
| 2 | 1000 | 30 | 10 | 5 | 5 | 2500 | 30.0 | 6.0 | 6.0 | 6.0 | 18.2 |
| 3 | 1000 | 30 | 10 | 5 | 15 | 2500 | 30.0 | 6.0 | 6.0 | 18.0 | 19.2 |
| 4 | 1000 | 30 | 10 | 5 | 30 | 2500 | 30.0 | 6.0 | 6.0 | 36.0 | 21.9 |
| 5 | 1000 | 30 | 10 | 5 | 50 | 2500 | 30.0 | 6.0 | 6.0 | 60.0 | 29.1 |
| 6 | 1000 | 30 | 10 | 5 | 75 | 2500 | 30.0 | 6.0 | 6.0 | 90.0 | 41.9 |
| 7 | 1000 | 30 | 10 | 5 | 100 | 2500 | 30.0 | 6.0 | 6.0 | 120.0 | 55.6 |
| 8 | 1000 | 30 | 10 | 5 | 125 | 2500 | 30.0 | 6.0 | 6.0 | 150.0 | 68.4 |
| 9 | 1000 | 30 | 10 | 5 | 150 | 2500 | 30.0 | 6.0 | 6.0 | 180.0 | 81.7 |
* The fluorescence change ΔF = F0 − F was calculated with respect to the F0 value measured in a non-spiked water sample obtained mixing the hydroalcoholic solution of 1b with ultrapure, HPLC-grade water (entry 0). The fluorescence values were measured at 416 nm for anthracene fluorophore 1b.