Ionic Liquid-Based Centrifuge-Less Cloud Point Extraction of a Copper(II)-4-Nitrocatechol Complex and Its Analytical...

Area of Science:

• Analytical Chemistry
• Environmental Chemistry

Background:

• Traditional methods for copper(II) determination often require centrifugation and can be time-consuming.
• Development of efficient and environmentally friendly extraction techniques is crucial for trace metal analysis.

Purpose of the Study:

• To develop a novel centrifuge-less cloud point extraction (CL-CPE) method for spectrophotometric determination of copper(II).
• To utilize a mixed micellar system of Triton X-114 and Aliquat® 336 (A336) for enhanced extraction efficiency.

Main Methods:

• Cloud point extraction (CL-CPE) without centrifugation.
• Spectrophotometric determination of copper(II) using 4-nitrocatechol (4NC) as a chelating agent.
• Formation of a ternary ion-association complex: (A336+)2[Cu(4NC)2].

Main Results:

• High molar absorption coefficient (8.9 × 10⁴ M⁻¹ cm⁻¹) and Sandell's sensitivity (0.71 ng cm⁻²).
• Linear response for copper(II) from 32-763 ng mL⁻¹ with a low limit of detection (9.7 ng mL⁻¹).
• Efficient extraction indicated by log Kex = 7.9.

Conclusions:

• The developed ionic liquid-assisted CL-CPE method is feasible, practical, simple, cost-effective, and environmentally friendly.
• The method demonstrated analytical competitiveness and was successfully applied to real samples like dietary supplements and infusion solutions.