Sensitivity improvement for antimony determination by using in-situ atom trapping in a slotted quartz tube and flame atomic absorption spectrometry

摘要

Significant improvement has been achieved for antimony determination using a slotted quartz tube (SQ.T) as an atom trap (AT) for in situ preconcentration and flame atomic absorption spectrometry (FAAS). The suggested technique consists of trapping analyte species during ordinary nebulization followed by releasing the collected analyte via introducing organic solvent. Procedures and analytical figures of merit have been presented for the techniques called FAAS, SQT-FAAS and finally SQT-AT-FAAS with the relevant comparisons. Analytical parameters, namely composition of the aqueous medium, sample flow rate, flame conditions, distance between burner head and SQT, sampling period and type of organic solvent and its volume have been optimized. Using SQT-AT-FAAS, a sensitivity enhancement of 369 fold has been obtained, 3 s limit of detection was 3.9 μg L~(-1) when 25.0 mL of sample was collected in 4.0 min. Interference effects of some elements on antimony signal were studied.