Cloud point extraction (CPE) and dispersive liquid-liquid microextraction (DLLME) applied in the development of analytical methods for metals preconcentration and spectrometric determination

Abstract

Separation and preconcentration are often required to eliminate interferences, increased sensitivity and improved detection limits of spectrophotometric and spectrometric techniques. Such processes include liquid-liquid extraction, cloud point extraction, solid phase extraction, co-precipitation and precipitation. The first has many applications in the determination of analytes at low concentrations and in complex matrices, in a number of samples such as environmental and biological samples. The main disadvantage of liquid-liquid extraction is the high consumption of toxic reagents, which can be hazardous to the environment. A proposal for the replacement of toxic solvents used in conventional liquid-liquid extraction, are surfactants, which enable the development of environmentally friendly methods of analysis, decreasing the amount of toxic waste discarded in the environment. This process is called cloud point extraction (CPE). The dispersive liquid-liquid microextraction (DLLME) also added to the advantages of liquid-liquid extraction with significant reduction in the consumption of solvents. This aim of this project is to use the CPE and DLLME processes in the development of analytical methods for the determination of ions such as cadmium, nickel, cobalt, copper and zinc and subsequent detection using the techniques of atomic absorption spectrometry - flame and or graphite furnace. Three complexing reagents will be used: 1 - (2-pyridylazo)-2-naphthol (PAN), di-2-pyridyl ketone saliciloilhidrazona (DPKSH) and di-2-pyridyl ketone benzoilhidrazona (DPKBH). (AU)