No abstract

A novel, exceptionally simple and rapid method has been developed for visual detection of Lglutamic acid (Glu) in aqueous solution. The chemosensor employed is easy to prepare and use with an added advantage of cost effectiveness. It exhibits an excellent selectivity and sensitivity towards Glu over other amino acids by both changes in absorption intensity and colorimetrically. The chemosensor provides a fast response time, with an LOD of about 7.96×10 -7 M suggesting that the chemosensor may be useful as a valuable practical sensor for environmental analyses of glutamic acid.

A reversible fluorescent-colorimetric imino-pyridyl bis-Schiff base receptor (N(1)E,N(4)E)-N(1),N(4)-bis(pyridine-4-ylmethylene)benzene-1,4-diamine for the detection of both Al(3+) and HSO3(-) in aqueous medium has been developed. Receptor exhibits an excellent selective fluorescent-colorimetric response toward Al(3+). The sensitivity of the fluorescent based assay (0.903 μM) for Al(3+) is far below the limit recommended in the World Health Organization (WHO) guidelines for drinking water (7.41 μM). From (1)H NMR data, the Job plot and the ESI-MS spectrum, 1 : 2 stoichiometric complexation between and Al(3+) has been established. Receptor shows remarkable detection ability in a wide pH range of 4-11 and was successfully utilised in the determination of Al(3+) in aqueous solution of bovine serum albumin protein, and of HSO3(-) in real food samples. Moreover, shows a highly selective colorimetric response to HSO3(-) by changing its colour from yellow to colorless immediately without any interference from other anions.

A simple, low-cost pyrene derivative containing a benzilmonohydrazone moiety has been exploited for the selective detection of Cu2+ by colorimetric, absorption, emission and bio-imaging methods. The sensitivity of the fluorescence based assay is 7.8 nM for Cu2+, which is far below the limit mentioned in the World Health Organization.

A reversible fluorescent-colorimetric azino bis-Schiff base receptor for the detection of Pb2+ in aqueous medium has been developed.