Bulut, Volkan N.; Demirci, Hamit; Ozdes, Duygu; Gundogdu, Ali; Bektas, Hakan; Soylak, Mustafa; Duran, Celal

A carrier element-free coprecipitation (CEFC) method was developed for the preconcentration and determination of trace Co(II) and Cu(II) in environmental and food samples using a novel thiosemicarbazone-derived Schiff base ligand (MBITAH). Unlike conventional coprecipitation approaches, the proposed strategy eliminates the need for inorganic carriers, reducing potential interferences and improving selectivity toward the target analytes. Under optimized conditions (pH 7.0, 1.5 mg ligand), quantitative recoveries were achieved with limits of detection of 1.16 and 0.79 µg L⁻1 for Co(II) and Cu(II), respectively. A preconcentration factor of 50 enabled sensitive determination by flame atomic absorption spectrometry (FAAS) with good precision (RSD ≤ 3.7%). The method exhibited good tolerance toward common matrix ions and was validated using certified-reference material (CRM-SA-C Sandy Soil C) and spike/recovery tests, showing agreement with certified values (p > 0.05). Its applicability was demonstrated in sea water, stream water, and food samples (red lentil and bulgur), confirming reliable performance in complex matrices. Compared with previously reported approaches, the proposed CEFC method offers a favorable balance between analytical performance, simplicity, and cost-effectiveness. In addition, greenness assessment using the AGREE tool yielded a score of 0.45, indicating a moderate-to-good level of environmental friendliness.

Bulut, Volkan Numan; Demirci, Hamit; Ozdes, Duygu; Gundogdu, Ali; Bekircan, Olcay; Soylak, Mustafa; Duran, Celal

A new separation and pre-concentration method was presented in this study for two trace heavy metal ions, lead (Pb2+) and cadmium (Cd2+) from aqueous solutions, based on a carrier element free co-precipitation (CEFC) method using a triazole derivate, 3-(4-tert-butylphenyl)−5-phenyl-4-(2-hydroxy-5-methoxybenzylamino)−4H-1,2,4-triazole as an organic co-precipitating agent. The method was optimized with some analytical parameters which affect the quantitative recoveries of study metals. According to the results, optimum pH of solution, quantity of co-precipitating agent, centrifugation and incubation time, and sample volume were determined as 6.0, 1.5 mg, 10 min, and 10 min, and 100 mL, respectively. In addition, no significant matrix interferences were observed over the recovery of the metal ions. For analytical figure of merit, RSD values of the method were found as 5.7 and 4.8 for Pb2+ and Cd2+, respectively. LOD values were also calculated as 2.0 µg L−1 for Pb2+ and 0.2 µg L−1 for Cd2+. The accuracy of method was checked with spiked/recovery tests and analysis of a standard reference material. The developed method was finally applied to the real liquid/solid samples under the optimum conditions.