Determination of metals in fish and shrimp (Farfantepenaeus paulensis) from Patos Lagoon (Pelotas- RS, Brazil) by MIP OES

Abstract

In the present work, the microwave induced plasma optical emission spectrometry technique was employed to determine the concentrations of Al, Cd, Cu, Hg, Mg, Sb and Zn in fish samples (catfish, mullet, wolf fish, spotted sorubim and croaker) and Al, Ba, Ca, Cd, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Sb, Ti and Zn in shrimp (Farfantepenaeus paulensis) samples. Samples were prepared by acid decomposition with reflux system. For fish analysis, two systems of sample introduction into plasma were compared: conventional nebulization and multimode system. In order to get the best conditions using the multimode system, parameters such as the concentrations of HCl and of reducing agent NaBH₄ were investigated. The method accuracy was assessed through analysis of certified reference materials and analyte addition tests. The obtained recoveries were satisfactory for both samples. For fish, the best results were obtained using the multimode system and the maximum concentrations (in mg·kg^-1) were: 6.43 to 24.7 for Al; 0.41 to 6.6 for Cu; 168.2 to 211.2 for Mg and 23.1 for Zn. For shrimp samples, the maximum concentrations (in mg·kg ^-1) were: 92.1 for Al; 1,070 for Ca; 4.57 for Cu; 87.9 for Fe; 451 for Mg; 8.9 for Mn and 29.2 for Zn. All concentrations found for Cd, Cu, Pb and Zn are within the limits permitted by the current legislation in Brazil for fish. The results showed the suitability of the present method using MIP OES technique for multielemental determination in fish and shrimp samples.

Keywords:
Fish; Shrimp; Metals; MIP OES; Acid decomposition