Table 2.
Elution times and concentrations of arsenic and co-eluted sulfur in model solutions with ΣH2S/ΣAs = 0.8 (Exp. 3) and ΣH2S/ΣAs = 26 (Exp. 7) (Fig. 2; Table 1)
| Exp. | Species | Elution time/s | Arsenic/μmol L-1 | Sulfur/μmol L-1 | Molar ratio (S/As)a |
| 3 | Arsenite | 217 | 12.3 | n.d. | - |
| Arsenate | 827 | 0.20 | n.d. | - | |
| S-As (1 : 1) | 922 | 0.17 | b | - | |
| S-As (2 : 1) | 1024 | 0.43 | 0.97 | 2.25 | |
| S-As (3 : 1) | 1129 | 0.32 | 1.06 | 3.31 | |
| S-As (4 : 1) | - | n.d. | n.d. | - | |
| 7 | Arsenite | 231 | 0.14 | n.d. | - |
| Arsenate | 815 | 0.04 | n.d. | - | |
| S-As (1 : 1) | 914 | 0.05 | b | - | |
| S-As (2 : 1) | 1016 | 1.16 | 2.78 | 2.40 | |
| S-As (3 : 1) | 1119 | 10.6 | 30.5 | 2.88 | |
| S-As (4 : 1) | 1205 | 0.28 | 1.09 | 3.91 |
aAmong all samples variability of molar S/As ratios for the 2 : 1, 3 : 1, and the 4 : 1 complexes was 2.1 ± 0.3, 3.1 ± 0.7, and 4.2 ± 0.3, respectively. bThe first S-As complex is likely to be a 1 : 1 complex -but in most cases the sulfur from this thioarsenite species co-eluted with sulfur from other sulfur species. This was evidenced by non-coincident retention times for As and S peaks. n.d., not detected.