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

Kiradzhiyska D., Milcheva N., Ruzmanova M., GENÇ F., Racheva P., Gavazov K.

Molecules, cilt.30, sa.15, 2025 (SCI-Expanded, Scopus) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 30 Sayı: 15
  • Basım Tarihi: 2025
  • Doi Numarası: 10.3390/molecules30153287
  • Dergi Adı: Molecules
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Aerospace Database, Biotechnology Research Abstracts, CAB Abstracts, Chemical Abstracts Core, Communication Abstracts, Food Science & Technology Abstracts, MEDLINE, Metadex, Veterinary Science Database, Directory of Open Access Journals, Civil Engineering Abstracts
  • Anahtar Kelimeler: 1,2-dihydroxy-4-nitrobenzene, Aliquat 336, centrifuge-less cloud point extraction, copper(II), mixed micelle-mediated system, spectrophotometric determination
  • İstanbul Yeni Yüzyıl Üniversitesi Adresli: Evet

Özet

A novel centrifuge-less cloud point extraction (CL-CPE) method was developed for the spectrophotometric determination of copper(II) using 4-nitrocatechol (4NC) as the chelating agent. The extraction system utilizes a mixed micellar phase composed of the nonionic surfactant Triton X-114 and the ionic liquid (IL) Aliquat® 336 (A336). The extracted ternary ion-association complex, identified as (A336+)2[Cu(4NC)2], exhibits a maximum absorbance at 451 nm, with a molar absorption coefficient of 8.9 × 104 M−1 cm−1 and a Sandell’s sensitivity of 0.71 ng cm−2. The method demonstrates a linear response in the copper(II) concentration range of 32–763 ng mL−1 and a limit of detection of 9.7 ng mL−1. The logarithmic extraction constant (log Kex) was determined to be 7.9, indicating efficient extraction. Method performance, evaluated by the Blue Applicability Grade Index (BAGI) and the Click Analytical Chemistry Index (CACI), confirmed its feasibility, practicality, simplicity, convenience, cost-effectiveness, environmental friendliness, and analytical competitiveness. The proposed IL-CL-CPE method was successfully applied to the analysis of a dietary supplement, a solution for infusion, and synthetic mixtures simulating various copper alloys.