Determination of trace tellurium by photochemical vapor generation-atomic fluorescence spectrometry using bifunctional Co-MOF-74 for preconcentration and sensitization

The determination of trace tellurium in real samples with complicated matrix can be rather challenging due to the low abundance and interferences. Herein, we report a new method for the highly sensitive detection of Te(IV) by photochemical vapor generation-atomic fluorescence spectrometry (PVG-AFS), utilizing Co-MOF-74 as an adsorbent and a precursor of Co2+ ion sensitizer for preconcentration and enhanced PVG efficiency. The synthesized Co-MOF-74 can completely adsorb Te(IV) within 10 min in a wide pH range. Following filtration and re-suspension in a dilute solution of formic and acetic acid, the adsorbed Te(IV) was converted to volatile compounds under the UV irradiation and swept to AFS for detection. A limit of detection of 0.08 ng/mL for Te(IV) was obtained after a 50-fold preconcentration. The proposed method was used for analysis of various natural water samples for trace Te(IV), with satisfactory spike recoveries achieved.