Determination of Copper in Water by Ionic Liquid Based Microextraction and Chemiluminescence Detection

Abstract

A versatile, sensitive, and green method based ultrasound-assisted, temperature-controlled, dispersive liquid–liquid microextraction with an ionic liquid and chemiluminescence detection was used for the determination of copper(II) at the ultra-trace level. After complexation by dithizone, copper(II) was extracted into the ionic liquid. Using high temperature and ultrasonic agitation, the copper complex easily migrated into the ionic liquid phase because of the larger contact area. After back extraction, the determination was performed by chemiluminescence based on the catalyzing effect of copper(II) on the decomposition of hydrogen peroxide with rhodamine B. Important parameters that affected the extraction efficiency and chemiluminescence intensity were optimized. Under the optimum conditions, a limit of detection for copper of 0.8 ng L⁻¹ was obtained with a linear calibration relationship. The method was applied to analyze environmental water samples for copper(II) with satisfactory results.

Keywords:

• Chemiluminescence
• Copper
• Dispersive liquid–liquid extraction
• Microextraction
• Temperature controlled
• Ultrasound assisted

Notes

DLLME: Dispersive Liquid–Liquid Micro Extraction; ICP-OES, inductively coupled plasma optical emission spectrometry; ETAS, Electro Thermal Atomic absorption Spectrometry; FAAS, Flame Atomic Absorption Spectrometry.

^a Mean of three determinations ± standard deviation.

^b Electrothermal atomic absorption spectroscopy.

^c  t-critical = 4.3 for n = 2 and P = 0.05.