Cobalt ion-enhanced photochemical vapor generation in a mixed acid medium for sensitive detection of tellurium(iv) by atomic fluorescence spectrometry†
A method of cobalt ion assisted enhancement of photochemical vapor generation-atomic fluorescence spectrometry (PVG-AFS) was proposed for sensitive determination of ultratrace tellurium(IV). With a mixture of 5% (v/v) formic acid and 20% (v/v) acetic acid as the reaction medium, more than 13-fold improvement in AFS intensity for Te(IV) was achieved simply by adding 1 mg L−1 Co2+ as a homogeneous catalyst. A possible reaction mechanism was proposed with the characterization results of GC-MS and electron paramagnetic resonance (EPR). Under optimal conditions, the limit of detection (LOD) for Te(IV) was 0.06 μg L−1, with a relative standard deviation (RSD) of 1.3% (10 μg L−1 Te, 7 times). The accuracy and utility of this methodology were validated by analysis of real water samples, with satisfactory recoveries of 91–108%.