Sensors Based on Single- and Double-Layer Plasticized Membranes for the Potentiometric Determination of Mefenamic and Phenylanthranylic Acids

Biomass-Derived Core–Shell Carbon Dots with Embedded Tripodal Receptors for the Selective Recognition of Mefenamic Acid in Pharmaceutical Formulations and Urine

“…Yield: 93.93% (0.78 mmol, 0.31 g), FT-IR (KBr) cm −1 : 3413 (broad OH), 2900−2800 (CH 2 ), 1633 (−C = N), 1468, 1437 (C−C), 1267, 1112 (C−O). 1 H NMR (500 MHz, CDCl 3 ): δ (ppm) 0.89 (3H, t, H 23 ), 1.62 (2H, sex, H 22 ), 2.23 (3H, s, H 16 ), 3.45 (2H, td, H 21 ), 3.69 (2H, s, H 12 ), 3.78 (2H, s, H 1 ), 3.80 (2H, s, H 6 ), 6.86 (1H, s, H 14 ), 6.88 (1H, dd, 4 J = 1.5, 3 J = 5 Hz, H 4 ), 7.04 (1H, dd, 4 J = 1.5, 3 J = 5 Hz, H 3 ), 7.14 (1H, dd, 4 J = 1.5, 3 J = 5 Hz, H 10 ), 7.19 (1H, s, H 17 ), 7.36 (1H, d, 3 J = 2, H 5 ), 7.58 (1H, td, 4 J = 2, 3 J = 7.5, H 9 ), 7.62 (1H, d, 3 J = 7.5, H 8 ), 8.19 (1H, s, H 19 ), 8.41 (1H, d, 3 J = 5, H 11 ); 13…”

“…These bands disappeared in the case of FCDs@ SiO 2 -TPA due to the formation of an azomethinic bond and new vibrational bands were observed at 794 cm −1 (Si−O−Si symmetric stretching), 963 cm −1 (Si−O symmetric stretching), 1074 cm −1 (Si−O−Si asymmetric stretching), and 1634 cm −1 (C�N) (Figure 1a). The 1 H NMR spectrum of TPA in CDCl 3 exhibited a singlet at 10.15 ppm due to the aldehydic proton (H 19 ), which shifted upfield to 8.41 ppm in the case of the model Schiff base compound due to azomethine bond formation with n-propylamine. 13 Thermogravimetric analysis (TGA) of FCDs revealed a mass loss of 98.60% when the the temperature was increased from room temperature to approximately 80 °C.…”

“…MFA is one of the most popular nonsteroidal anti-inflammatory drugs prescribed to get relief from body pains including arthritis and rheumatic problems . MFA is included in the list of priority pollutants as its presence in the environment may lead to heart attack, acute hepatic necrosis, and increased mortality rate. − The recent spectrofluorimetric and electrochemical sensors developed for its analysis involve sodium dodecyl sulfate (LOD = 1326 μM), tris­(2,2′-bipyridyl)­ruthenium­(III) (LOD = 0.210 μM), NiO-SWCNT and 2,4-dimethyl- N /-[1-(2,3-dihydroxyphenyl)­methylidene]­aniline (LOD = 0.500 μM), stilbene (LOD = 4 μM), plasticized membrane (LOD = 280 μM), ion sensor (LOD = 0.620 μM), carbon nanotubes (LOD = 1.000 μM), and Ni-curcumin nanoparticles (LOD = 95.90 μM). − However, the smaller accuracy of results is a major drawback as these probes are nonselective toward MFA. Similar problems are faced when detection probes and adsorption supports lack defined coordinating sites .…”