Deep eutectic solvent-based ultrasonic-assisted dispersive liquid–liquid microextraction combined with graphite furnace atomic absorption spectrometry for Te(IV) and Te(VI) in water and beverage samples

Based on ultrasound-assisted dispersive liquid–liquid microextraction with deep eutectic solvent (DES) as an eco-friendly extractant, an efficient method was proposed for Te(IV) and Te(VI) by graphite furnace atomic absorption spectrometry. Ammonium pyrroinedithiocarbamate (APDC) was used as a chelating reagent for Te(IV). DES was prepared from choline chloride and phenol for extraction of Te(IV)-APDC complexes. The experimental results showed that Te(IV) was quantitatively extracted in the pH range of 5.0–8.0, while Te(VI) remained in the aqueous phase. Te(VI) content was obtained by subtracting Te(IV) from total Te concentration. Total Te was determined after reducing Te(VI) into Te(IV). The main factors affecting the separation, preconcentration and determination of target species were investigated. Under the optimized conditions, limit of detection and limit of quantification were found to be 3.5 ng L −1 and 12 ng L −1 for Te(IV) with a enrichment factor of 115-fold, respectively. The calibration graph is linear in the range of 0.02–10 ng mL −1 . The precision expressed as relative standard deviation was less than 8.4% ( n = 9 for intra-day and n = 5 for inter-day). This method was utilized for the analysis of Te(IV) and Te(VI) in beverage samples with satisfactory results. To verify the accuracy of the proposed method, a certified reference material of water sample was analyzed, and the obtained result was in good agreement with the certified value. Recoveries of spike experiments ranged from 91.8 to 107%.