Abstract—Design of a new specific colorimetric chemosensor for detection of Cu2+ is a challenge in the context of interference from coexisting metal ions in aqueous solution. Therefore, ortho (L1), meta (L2) and para (L3) bearing benzoyl thiourea moiety as binding site and pdimethylaminobenzaldehyde moiety as signal group were designed and synthesized to apply as colorimetric chemosensors for detection of Cu2+. The structure was confirmed by characterized the compound using Elemental analysis, Fourier Infrared (FTIR) and proton Nuclear Magnetic Resonance (1H NMR) spectroscopy. Fuctional group of C=O, N-H, C=N and C=S was found at 1663 cm-1, 3336 cm-1, 1596 cm-1, 1064 cm-1 respectively while 1H NMR show peaks of alkane (CH2), benzene (Ar-H), CONH, CSNH at 3.7 – 3.99, 7.05 – 7.79, 8.07, and 9.59 respectively. Elemental analysis for L1-L3 C21H26N5OSBr found was compatible with the expected theoretical calculation. For application, all of these three sensors showed excellent colorimetric specific selectivity and high sensitivity for Cu2+ in acetonitrile/water binary solutions so only L1 was selected for further studies towards sensitivity. When Cu2+ was added to the solution of L1, a dramatic color change from orange to brown, while other cations Fe2+, Zn2+, Ni2+, Co2+, Cr3+ and Mn2+ did not interfere with the recognition process for Cu2+. The detection limits of L1 were 1.5 × 10-4 M and 1.7 × 10-5 M of Cu2+ using the visual color changes and Ultraviolet-visible spectroscopy changes respectively. Test strips based on L1 were fabricated
Index Terms—Benzoyl thiourea, dimethylaminobenzaldehyde, copper (II) cation, colorimetric chemosensor, test strips.
The authors are with the Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, Malaysia (e-mail: sharizal187@perlis.uitm.edu.my, nurulasmahamedan92@rocketmail.com, hamiz410@salam.uitm.edu.my).
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Cite: Sharizal Hasan, Nurul Asma Hamedan, and Hamizah Mohd Zaki, "Application of P-Dimethylaminobenzaldehyde Benzoylthiourea as a Colorimetric Chemosensor for Detection of Cu2+ in Aqueous Solution," International Journal of Chemical Engineering and Applications vol. 8, no. 1, pp. 22-27, 2017.
