Development of a Pre-concentration Method for Nickel in Chocolate Samples using Magnetic Dispersive Solid- phase Extraction Followed by Flame Atomic Absorption Spectrometry

In  this  study,  magnetic  dispersive  solid-phase  extraction  (MDSPE)  combined  flame atomicabsorption  spectrometry  (FAAS) was  used  as  a  new  method  for  the  analysis  of  nickel preconcentration  in  chocolate  samples.  A  suitable  mixture  of  magnetic  adsorbent  1(2,3-dihydroxypropyl)-1,4diazabicyclo[2.2.2]  octanylium  [DABCO-PDA]  and  chloro-functionalized Fe3O4  nanoparticles  (NPs)  with  chelating  agent  dimethylglyoxime  (DMG)  was  added  into  an aqueous  solution. Adsorption  behaviors  of Ni  (II)  ion  on  Fe-[DABCO-PDA]  NPs  were  studied. Finally,  the  main  parameters  affecting  the  extraction  and  determination  of  the  analysis  were investigated  in  detail.According  to  the findings,  the  analyte  was  quantitatively  holed  on  Fe-[DABCO-PDA]  NPs  in pH  8,  eluted  totally  with  3  ml  of  ethanol  HNO3 2%  (v/v),  and  adsorbed about 50 mg. Under the optimal experimental conditions, the detection limit (LOD) was 0.18 µg Kg-1, with a standard deviation of1.8-4% (n=5). The linear working range of the calibration curve was 1-250 µg Lit-1 and the recovery values ranged from 92 to 97% for all samples. The proposed method was fast, simple, effective and high tolerability to the presence of the ions. Moreover, high sensitivity,  better  recovery,  and  the  use  of  environmentally  friendly  solvents  are  the  other advantages of this technique.