Indandione oligomer@graphene oxide functionalized nanocomposites for enhanced and selective detection of trace Cr²⁺ and Cu²⁺ ions

Herein, using 1, 3 indandione and three thiophene unit by Suzuki coupling reaction, small organic oligomer–based indandione derivative, 2-(5″-hexyl-[2,2′:5′2″ terthiophen]-5-yl) methylene)-1H-indene-1,3(2H) dione oligomer (HTD) was synthesized. A functional and highly effective nanocomposite based on the synthesized HTD oligomer and graphene oxide (GO) was further synthesized and utilized to fabricate high-sensitive and selective chemical sensor. The synthesized HTD@GO functionalized nanocomposites were further examined by several techniques and finally coated on the glassy carbon electrode (GCE) to fabricate the chemical sensor. Due to the synergistic impacts of HTD oligomer and GO, the functionalized HTD@GO nanocomposite exhibited outstanding physiochemical, structural, and surface characteristics. Thus, using an electrochemical method, the HTD@GO/GCE sensor probe demonstrated the outstanding simultaneous trace detection of heavy metals such as Cr²⁺ and Cu²⁺ ions. The HTD@GO/GCE sensor probe revealed a strong selectivity towards Cr²⁺ and Cu²⁺ ions when compared to other metal ions (Al³⁺, Zn²⁺, K⁺, Mn²⁺). Importantly, the HTD@GO/GCE-based sensor exhibited relatively good dynamic linear ranges of 1–100 µM and detection limit values of ~3.65 μM and ~2.25 μM, respectively, for trace Cr²⁺ and Cu²⁺ ions. The HTD@GO/GCE sensor probe has low relative standard deviations (RSDs) of ~10% and ~6.4% for Cr²⁺ and Cu²⁺ ions, respectively, as suggested by the repeatability test. Analyzing actual water samples was also used to test the reliability of the functionalized nanocomposite sensor. Graphical abstract: HTD@GO/GCE-based-sensor presents good detection limit values of ~3.65 μM and ~2.25 μM with excellent linear dynamic for Cr²⁺ and Cu²⁺ ions, respectively. [Figure not available: see fulltext.]