Ultrasonic assisted switchable solvent based on liquid phase microextraction combined with micro sample injection flame atomic absorption spectrometry for determination of some heavy metals in water, urine and tea infusion samples

A green switchable solvent based on liquid phase microextraction (SS-LPME), has proposed to extract some heavy metal ions (Cd, Ni, Pb and Co) from various samples by micro sampling flame atomic absorption spectrometry (FAAS). Triethylamine (TEA) and protonated triethylamine carbonate (P-TEA-C) as green switchable solvents were used in two forms in the presence of CO2. Sodium hydroxide (NaOH) was performed to convert protonated triethylamine carbonate to triethylamine and as a result, the complexes of metal ions were extracted into TEA phase. Ultrasonic energy was introduced to accelerate formation of fine droplets of the extractant into the aqueous solution, and enlarge contact surface between both immiscible liquids. Several factors influencing the recovery and determination of analytes were studied. According to the results, the limits of detection were in the range of 0.24 and 0.76 mu g L-1 and the relative standard deviations (RSDs, n = 10) in the range of 1.3 to 3.8% at 50 mu g L-1 for all analytes were found. Also, preconcentration factors (PFs) >100 were obtained for all analytes. The accuracy of the proposed method was verified using a certified reference material (CRM). Finally, the method was effectively utilized to the analysis of Cd, Ni, Pb and Co in water, urine and tea infusion samples. (C) 2017 Elsevier B.V. All rights reserved.