Quantification of Nitrite/Nitrate in Food Stuff Samples Using 2-Aminobenzoic Acid as a New Amine in Diazocoupling Reaction

2-Aminobenzoic acid has been used as an amine in diazocoupling reaction to form an azo dye in the quantification of nitrite/nitrate at trace level. The formed azo dye has an absorption maximum at 550 nm in aqueous phase, and the resulted dye can be extracted into organic solvent to lower the detection limit. The method obeys Beer's law in the concentration range 0–10 µg of nitrite in 25 ml of aqueous solution with a molar absorptivity of 3.6 × 103 L mol−1 cm−1 and 0–2 µg of nitrite in 5 ml of organic phase. The detection limit of the dye has been found to be 0.056 μg ml−1. Nitrate is determined by reducing it to nitrite after passing through a copperized cadmium reductor column. The effect of interfering ions on the determination of nitrite/nitrate has been described. The developed method has been applied to determine the nitrite/nitrate trace level in vegetable, fruit juice, and milk powder samples

Micelle Mediated Trace Level Sulfide Quantification through Cloud Point Extraction

A simple cloud point extraction protocol has been proposed for the quantification of sulfide at trace level. The method is based on the reduction of iron (III) to iron (II) by the sulfide and the subsequent complexation of metal ion with nitroso-R salt in alkaline medium. The resulting green-colored complex was extracted through cloud point formation using cationic surfactant, that is, cetylpyridinium chloride, and the obtained surfactant phase was homogenized by ethanol before its absorbance measurement at 710 nm. The reaction variables like metal ion, ligand, surfactant concentration, and medium pH on the cloud point extraction of the metal-ligand complex have been optimized. The interference effect of the common anions and cations was studied. The proposed method has been successfully applied to quantify the trace level sulfide in the leachate samples of the landfill and water samples from bore wells and ponds. The validity of the proposed method has been studied by spiking the samples with known quantities of sulfide as well as comparing with the results obtained by the standard method

Amino-​calixarene-​modified graphitic carbon as a novel electrochemical interface for simultaneous measurement of lead and cadmium ions at picomolar level

Amino-​calixarene-​derivatized graphitic carbon electrode has been used in the simultaneous quantification of lead and cadmium ions at picomolar level. The graphitic carbon has been chem. modified using amino-​calixarene as an indicator mol. through microwave irradn., and it has been characterized by NMR, mass, and Fourier transform IR spectroscopy (FTIR) techniques. The proposed sensor has shown linearity in the concn. range 10-​120 pM with detection limits of 3.3 and 3.5 pM for lead and cadmium, resp. The proposed sensor has been successfully applied to quantify lead and cadmium levels in battery effluents, alloy materials, and sewage water sample matrixes. The results obtained by the proposed sensor are in agreement with the results of the std. protocols

Micellar mediated trace level mercury quantification through the rhodamine B hydrazide spirolactam ring opening process

The micellar mediated trace level estn. of mercury in industrial effluent sample by the rhodamine B hydrazide spirolactam ring opening process is described. The catalytic reaction of mercuric ion with colorless rhodamine B hydrazide to form pink colored rhodamine B through amide bond cleavage at pH 5 forms the basis of this reaction. The dye obtained was extd. from the aq. phase into non-​ionic surfactant using Triton X-​114 through cloud point formation and its absorbance was measured at 556 nm. The reaction conditions such as concns. of rhodamine B hydrazide and Triton X-​114, effect of NaCl concn. on cloud point temp. and the efficiency of extn. were optimized. The selectivity of the method towards mercury in the presence of various ions was studied. The validity of the method was examd. by spiking real samples with known amts. of mercury and carrying out recovery studies. The results obtained by the proposed method were compared with the std. dithiazone method. The preconcn. and enrichment factors were found to be 5 and 12 resp. The limit of detection and the linear range were found to be 1.4 ng ml-​1 and 10-​100 ng ml-​1 resp. The relative std. deviation was found to be 0.35​% at 20 ng ml-​1

Trace Level Arsenic Quantification through Cloud Point Extraction: Application to Biological and Environmental Samples

A sensitive solvent-free extraction protocol for the quantification of arsenic at trace level has been described. It is based on the reaction of arsenic (V) with molybdate in acidic medium in presence of antimony (III) and ascorbic acid as a reducing agent to form a blue-colored arsenomolybdenum blue complex. The complex has been extracted into surfactant phase using Triton X-114, and its absorbance was measured at 690 nm. The detection limit, working range, and the relative standard deviation were found to be 1 ng mL−1, 10–200 ng mL−1, and 1.2%, respectively. The effect of common ions was studied, and the method has been applied to determine trace levels of As(III) and As(V) from a variety of samples like environmental, biological, and commercially procured chemicals

A new rhodamine B based fluorometric chemodosimeter for Cu2+ ion in aqueous and cellular media

A simple, sensitive and selective fluorescent chemo dosimeter rhodamine B phenyl hydrazide (RBPH) for Cu2+ was proposed. This probe is non fluorescent and colorless but exhibits fluorescent enhancement at 580 nm and displayed color change from colorless to pink for Cu2+ in the pH range 1-6. Fluorescence microscope experimental results reveals that this chemo sensor is cell permeable and can be used for fluorescence imaging of Cu2+ ions in living cells. This probe can detect Cu2+ with good linear relationships from 10 to 100 nM with r=0.99971 then limit of detection was found to be 0.015 nM with +/- 0.91% RSD at 10 nM concentrations. 2013 Elsevier B.V. All rights reserved

CeO2 nanoparticle-modified electrode as a novel electrochemical interface in the quantification of Zn2+ ions at trace level: application to real sample analysis

A simple strategy has been proposed to quantify Zn2+ ions using CeO2 nanoparticle-modified glassy carbon electrode. The CeO2 nanoparticles were prepared by sucrose-nitrate decomposition method, and it was characterized by X-ray diffraction (XRD), FT-IR, TEM, and surface area analyzer. The synthesized CeO2 nanoparticles were used as modifier molecules as a thin film on glassy carbon electrode (GCE) in the trace level quantification of Zn2+ by using cyclic voltammetry (CV) and differential pulse anodic stripping voltammetry (DPASV) techniques. The fabricated sensor exhibited a good analytical response towards Zn2+ ions. The modified electrode showed a wide linearity in the concentration range 20–380 μg L−1 with a limit of detection 0.36 μg L−1. The proposed electrochemical sensor was successfully applied to trace level Zn2+ quantification from real sample matrices