Multivariate optimization of an ultrasound-assisted extraction procedure for Cu, Mn, Ni and Zn determination in ration to chickens

Joelia M Barros,Marcos A Bezerra,Anderson S Souza,Baraquizio B Do Nascimento Junior,Gisseli S Valasques,Nadia M De Aragao

doi:10.1590/s0001-37652013000300005

Abstract

In this work, multivariate optimization techniques were used to develop a method based on the ultrasound-assisted extraction for copper, manganese, nickel and zinc determination from rations for chicken nutrition using flame atomic absorption spectrometry. The proportions of extracting components (2.0 mol.L-1 nitric, hydrochloric and acetic acid solutions) were optimized using centroid-simplex mixture design. The optimum proportions of this mixture taken as percentage of each component were respectively 20%, 37% and 43%. Variables of method (sample mass, sonication time and final acid concentration) were optimized using Doehlert design. The optimum values found for these variables were respectively 0.24 g, 18s and 3.6 mol.L-1. The developed method allows copper, manganese, nickel and zinc determination with quantification limits of 2.82; 4.52; 10.7; e 9.69 µg.g-1, and precision expressed as relative standard deviation (%RSD, 25 µg.g-1, N = 5) of 5.30; 2.13; 0.88; and 0.83%, respectively. This method was applied in the analytes determination from chicken rations collected from specialized commerce in Jequié city (Bahia State/Brazil). Application of paired t-test at the obtained results, in a confidence level of 95%, does not show significant difference between the proposed method and the microwave-assisted digestion.

Highlights

Nowadays, Brazil is a major producer and exporter of chicken meat, and in 2007 produced 10.3 million tons and exported 3.2 million for foreign market
The development of fast and accurate methods to allow determining amounts of micro nutrients such as Cu, Mn, Ni and Zn in rations for animal nutrition is of concern due the necessity of monitoring their levels and to ensure that metals are offered in adequate concentration to the chickens
Acid solutions are usually used as extracting agents due to their good efficiency

Summary

Introduction

Brazil is a major producer and exporter of chicken meat, and in 2007 produced 10.3 million tons and exported 3.2 million for foreign market. The domestic consumption of chicken meat in the country exceeded the consumption of other meats, such as beef and pork. Assessing factors such as adequate food for birds is very important to improve the quality of the produced meat (Roppa 2008). Determining mineral content in rations for animal nutrition is of great importance in assessing its quality, mainly due to the necessity of verifying the quantities of mineral nutrients supplied by these rations and evaluating the possibility of contamination by toxic metals (such as Pb, Hg and Cd) that can often be present in rations (Edwards and Veltman 1983)

Methods

Results

Conclusion