Table 5.
Short comparison of methods of thallium speciation analysis using SPE for thallium species separation
| Sorbent l | LOD [ng mL−1] |
Effects of pH | Interfering ions (tolerable excess) | General advantages/disadvantages |
Ref. |
|---|---|---|---|---|---|
| SGX C18 modified with DDTC | 0.05 Tl(I) 0.21 Tl(III) |
not studied | 1000 - Cu(II), 700 - Zn(II) and Sn(II), 500 - Pb(II) and 100 - Cd(II) | direct speciation of Tl(I) and Tl (III)/low tolerance for Tl(I) excess | 15 |
| nano-Al2O3 | 800 Tl(III) | best sorption at pH 3.0–4.5 | 5 - Ca(II) and Mg(II), 10 - Zn(II), 1,5 Pb(II), 3,0 - Ga(III), 9,5 - Sb(III), 10 - Ge(IV), Se(IV), 7,5 - Re(IV), 2 Li(I), 5 V(V), 6 - Sr(II), 7 - Mo(VI), 10 - As(III), 70 - NO3 − and SO4 −, 60 - CO3 2−, 10 - PO4 3−, 100 - Cl− | high sorption capacity and rapid separation/breakthrough volume lower than 25 mL and high LOD | 16 |
| Al2O3-oxine | 2.5 Tl(I) | Tl(I) deposition at pH 2.5 to 11 | 1000 - Mg(II), Na(I) K(I), Zn(II), Pb(II), Cu(II), Co(II), Ni(II),Cs(I), I−, Cl, SO3 2−; 750 - Cd(II), Ag(I), 500 - Ca(II), Fe(III), CO3 2− | simple preparation of microcolumn, high reproducibility/long time of sample preparation before loading | 19 |
| modified silica | 0.72 Tl(III) | not studied | 250 - Cl− and 100 - NO3 −, SO4 2−, Ca(II), Mg(II), K(I), Al(III) and Fe(III) | use of AAS and determination of Tl(III)/indirect speciation analysis of Tl | 20 |
| Chromosorb 105 | 0.034 Tl(III) | not studied | 500 000-Ca(II) and Zn(II), 250 000-CO3
2−, PO4
3−, 5000 000- Fe(II), Fe(III), Al(III), Cl-, 2500 000 Na(I) and K(I), 2000 000 Mg(II), 1000 000 SO4 2− and 25 000 Ni(II) and Cu(II) |
simple, reliable way of Tl(III) preconcentration and low LOD/suitable only for AAS determination and important interferences from Cr and Co cations | 24 |
| Al2O3 - SDS | 0.025 Tl(I) 0.16 Tl(III) | sample pH 5–6 | 500 - Pb and Cd, 2000 – Zn | direct speciation of Tl(I) and Tl(III), self-made column and high sorption capacity/use of conc. acid as eluent | this work |
Abbreviations: SGX C18: silica gel with octadecyl-groups, DDTC: diethyldithiocarbamate, SDS: sodium dodecyl sulfate