Direct Immersion Single-Drop Microextraction and Continuous-Flow Microextraction for the Determination of Manganese in Tonic Drinks and Seafood Samples

摘要

Two methods based on direct immersion single-drop microextraction (DI-SDME) and continuous-flow microextraction (CFME) were developed. Both methods were used for the determination of manganese by graphite furnace atomic absorption spectrometry. The reagent 1-(2-pyridylazo)-2-naphthol (PAN) was used as a complexing agent and 1-butyl-3-methylimidazolium hexafluorophosphate [C4MIM][PF6] as an extraction solvent. The extraction efficiencies were compared so that some variables, such as the volume of solvent, time of extraction, stirring speed, and flow rate, were optimized using the univariate method. The limits of detection were 3.9 and 7.9 ng L(-1)for DI-SDME and CFME methods, respectively. The enrichment factor for DI-SDME was 18 and for CFME was 15. The accuracy of the method was assessed by analyzing the certified reference material of mussel tissue (SEM 2976), and recovery tests ranged from 92 to 112%. The two categories of LPME are presented as excellent alternatives for the determination of manganese in real samples of tonic drinks and seafood, showing benefits such as low consumption of reagents, ease of operation, and low cost. The DI-SDME-based method is superior to the CFME method if practical aspects are considered, especially for two advantages: less sample volume required and less time to reach equilibrium.