Solidified Floating Organic Drop Microextraction for the Detection of Trace Amount of Lead in Various Samples by Electrothermal Atomic Absorption Spectrometry

Abstract

A novel method was developed for determination of trace amounts of lead in water and food samples. Solidified floating organic drop microextraction was used to preconcentrate the lead ion. After the analyte was complexed with 1-(2-pyridylazo)-2-naphthol, undecanol and acetonitrile were added as extraction and dispersive solvent, respectively. Variables such as pH, volumes of extraction and dispersive solvents, and concentration of chelating agent were optimized. Under the optimum conditions, the detection limit of Pb (II) was determined as 0.042 µg L^-1 with an enrichment factor of 300. The relative standard deviation is <10%. Accuracy of the developed procedure was evaluated by the analysis of certified reference material of human hair (NCS DC 73347) and wastewater (SPS-WW2) with satisfactory results. The developed procedure was then successfully applied to biscuit and water samples for detection of Pb (II) ions.

Figure 1

Schematic diagram of DLLME-SFO method.

Figure 2

The effect of the extraction solvent volume on absorbance of lead with SFODME. Extraction circumstances: Pb: 10 µgL⁻¹; pH: 9; extraction solvent, 1-undecanol (100 µL); sample volume, 10 mL; dispersive solvent, acetonitrile (200 µL); % 1.6 NaCl; chelating reagent [PAN], 1 × 10⁻⁴ mol L⁻¹.

Figure 3

The effect of dispersive solvent volume on absorbance of lead for SFODME. Extraction circumstances: Pb: 10 µgL⁻¹; pH: 9; extraction solvent, 1-undecanol (100 µL); sample volume, 10 mL; pH: 9; % 1.6 NaCl chelating reagent [PAN], 1 × 10⁻⁴ mol L⁻¹.

Figure 4

The effect of pH on the extraction of lead with SFODME. Extraction circumstances: Pb: 10 µgL⁻¹; extraction solvent, 1-undecanol (100 µL); sample volume, 10 mL; dispersive solvent, acetonitrile (200 µL); % 1.6 NaCl; chelating reagent [PAN], 1 × 10⁻⁴ mol L⁻¹.

Figure 5

The effect of 1-(2-pyridylazo)-2-naphthol concentration on absorbance of lead with SFODME. Extraction circumstances: Pb: 10 µgL⁻¹; pH: 9; extraction solvent, 1-undecanol (100 µL); sample volume, 10 mL; dispersive solvent, acetonitrile (200 µL); chelating reagent [PAN], 1 × 10⁻⁴ mol L⁻¹.