Exploitation of a simple Schiff base as a ratiometric and colorimetric chemosensor for glutamic acid

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.

Sequential Fluorescence Recognition of Molybdenum(VI), Arsenite, and Phosphate Ions in a Ratiometric Manner: A Facile Approach for Discrimination of AsO2–and H2PO4–

“…Job’s plot 68,69 supports 1:2 (mole ratio) binding stoichiometry between L and Mo(VI) (Figure S8, SI), corroborated by the electrospray ionization mass spectrometry (ESI-MS) image ( m / z , 762.18 for [M1 + H] + ) (Figure S9, SI) and single-crystal X-ray structure of M1. Treatment of fluorescence titration data by the Hill equation allows determination of the association constant, 4.21 × 105 M –1 (Figure S10, SI).…”

“…The emission intensity of C1 changes ratiometrically with increasing H 2 PO 4 – concentration having a linear region (Figures 12 and S23, SI). The binding affinity calculated using the Hill equation 69 is 2.11 × 10 5 M –1 , much stronger than that observed for AsO 2 – by M1 supra (Figure S24, SI). The 1:1 (mole ratio) interaction between C1 and H 2 PO 4 – is observed from Job’s plot (Figure S25, SI) and corroborated by ESI-MS spectra, m / z 1008.8445 (for [C3 + H] + ).…”

“…Spectroscopic features of L are governed by pH of the media, as it has pH-susceptible donor sites. 69 Furthermore, biological use of L demands its efficiency at physiological pH. Hence, the effect of pH on the emission profile of L in the presence and absence of Mo(VI) is tested (pH 3.0–12.0).…”

“…Job’s plot 67−71 supports 1:1 binding (mole ratio) between M1 and AsO 2 – (Figure S16, SI), corroborated by the mass spectrum of the [M1–AsO 2 – ] adduct. The binding constant 69 of M1 for AsO 2 – is 6.49 × 10 4 (Figure S17, SI). The quantum yields of the M1 and its AsO 2 – adduct are 0.156 and 0.632, respectively.…”

A Highly Sensitive Amperometric Glutamate Oxidase Microbiosensor Based on a Reduced Graphene Oxide/Prussian Blue Nanocube/Gold Nanoparticle Composite Film-Modified Pt Electrode

“…Many analytical techniques, such as fluorometric [10], spectrophotometric [11], chromatographic [12], and colorimetric methods [13], have been developed to measure glutamate in neurochemical analysis applications. Despite their high sensitivity, these methods still have not been widely applied in practical applications because of certain limitations, including high labor intensity, being overly time consuming, requiring expert handling, and involving sample pre-treatment [14].…”