Application of chitosan functionalized with 3,4-dihydroxy benzoic acid moiety for on-line preconcentration and determination of trace elements in water samples

Chitosan resin functionalized with 3,4-dihydroxy benzoic acid (CCTS-DHBA resin) was used as a packing material for flow injection (FI) on-line mini-column preconcentration in combination with inductively coupled plasma-atomic emission spectrometry (ICP-AES) for the determination of trace elements such as silver, bismuth, copper, gallium, indium, molybdenum, nickel, uranium, and vanadium in environmental waters. A 5-mL aliquot of sample (pH 5.5) was introduced to the minicolumn for the adsorption/preconcentration of the metal ions, and the collected analytes on the mini-column were eluted with 2 M HNO3, and the eluates was subsequently transported via direct injection to the nebulizer of ICP-AES for quantification. The parameters affecting on the sensitivity, such as sample pH, sample flow rate, eluent concentration, and eluent flow rate, were carefully examined. Alkali and alkaline earth metal ions commonly existing in river water and seawater did not affect the analysis of metals. Under the optimum conditions, the method allowed the determination of metal ions with detection limits of 0.08 ng mL(-1) (Ag), 0.9 ng mL(-1) (Bi), 0.07 ng mL(-1) (Cu), 0.9 ng mL(-1) (Ga), 0.9 ng mL(-1) (In), 0.08 ng mL(-1) (Mo), 0.09 ng mL(-1) (Ni), 0.9 ng mL(-1) (U), and 0.08 ng mL(-1) (V). By using 5 mL of sample solution, the enrichment factor and collection efficiency were 8-12 fold and 96-102%, respectively, whereas the sample throughput was 7 samples/hour. The method was validated by determining metal ions in certified reference material of river water (SLRS-4) and nearshore seawater (CASS-4), and its applicability was further demonstrated to river water and seawater samples.</p

A novel chemiluminescence assay of organophosphorous pesticide quinalphos residue in vegetable with luminol detection

<p>Abstract</p> <p>Background</p> <p>Organophosphorous pesticides are the most popular pesticides used in agriculture. As acetylcholinesterase inhibitors, organophosphorous pesticides are toxic organic chemicals. The control and detection of organophosphorous pesticide residue in food, water, and environment therefore plays a very important role in maintaining physical health. A sensitive, rapid, simple chemiluminescence(CL) method has been developed for the determination of quinalphos based on the reaction of quinalphos with luminol-H₂O₂in an alkaline medium. The method has been applied to detection of quinalphos in vegetable samples with satisfactory results.</p> <p>Results</p> <p>The CL method for the determination of organophosphorous pesticide quinalphos is based on the phenomenon that quinalphos can apparently enhance the CL intensity of the luminol-H₂O₂system. The optimal conditions were: luminol concentration 5.0 × 10^-4mol/L, H₂O₂concentration 0.05 mol/L.pH value 13. In order to restrain the interference from metal ions, 1.0 × 10^-3mol/L of EDTA was added to the luminol solution. The possible mechanism was proposed.</p> <p>Conclusion</p> <p>Under the optimum reaction conditions, CL was linear with the concentration of quinalphos in the range of 0.02 μg/mL -1.0 μg/mL and the detection limit was 0.0055 μg/mL (3σ). This method has been successfully applied to the detection of quinalphos in vegetable samples. According to the experimental data, the average recoveries for quinalphos in cherry tomato and green pepper 97.20% and 90.13%. Meanwhile, the possible mechanism was proposed.</p

Insight into the biosensing of graphene

Graphene oxide, a century old material has attracted the interest of researchers owing to its specific 2D structure and unique electronic, optical, thermal, mechanical and electrochemical properties. The recent advancements in the field of biotechnology and biomedical engineering are targeted at exploring the biosensing applications of graphene oxide due to its biocompatibility. It is considered to be one of the most versatile materials, with wide range of applications which can be tailored by functionalization of the different oxygen containing groups present in the structure. In this review the focus is on the biosensing applications of graphene oxide, detection of analytes with high sensitivity and selectivity. This would give insight into the designing of feasible protocols for the analysis of therapeutic diseases and environmental safety, thereby improving the quality of human life

Extractive Spectrophotometric Determination of Malathion in Environmental Samples Using Gention Violet

A new simple and selective spectrophotometric method is developed for the determination of malathion by using Gention violet is described. The method was based on the alkaline hydrolysis of malathion in presence of sodium ethoxide to form sodium dimethyl dithiophosphate (Na-DMDTP). The Na-DMDTP was formed as an ion-pair complex with cationic dye, gention violet. The ion-pair complex was extracted into chloroform. The color of the organic layer was measured at 587 nm. The method was applied to the determination of malathion residues in water, grain and soil sample

JSCS–3559 Short

Extractive spectrophotometric determination of copper(II) in water and alloy samples with 3-methoxy-4-hydroxy benzaldehyde-4-bromophenyl hydrazone (3,4-MHBBPH

Extractive spectrophotometric determination of copper(II) in water and alloy samples with 3-methoxy-4-hydroxy benzaldehyde-4-bromophenyl hydrazone (3,4-MHBBPH)

A facile, sensitive and selective extractive spectrophotometricmethod was developed for the determination of copper(II) in various water and alloy samples using a newly synthesized reagent, 3-methoxy-4-hydroxy benzaldehyde 4-bromophenyl hydrazone (3,4-MHBBPH). Copper(II) forms a orange colored complex with (3,4-MHBBPH) in acetate buffermedium (pH 4) which increases the sensitivity and the complexwas extracted into chloroform. Under optimum conditions, the maximum absorption of the chloroform extract was measured at 462 nm. The Beer law was obeyed in the range of 0.20 to 4.0 mg ml-1 of copper. The molar absorptivity and the Sandell's sensitivity of the complex were 2.0520 ´ 104 mol-1 cm-1 and 0.2540 mg cm-2, respectively. The detection limit was found to be 0.0270 mg mL-1. Adetailed study of various interfering ions made the method more sensitive. The method was successfully applied for the determination of Cu(II) in water and alloy samples. The performance of the present method was evaluated in terms of Student 't' test and Variance ratio 'f ' test, which indicate the significance of the present method over reported methods

Spectrophotometric Determination of Chromium in Water, and Pharmaceutical Samples Using 1-Naphthol

Facile and sensitive spectrophotometric methods for the determination of trace and ultra trace amounts of chromium (VI) are described. 4-aminoantipyrine (APP) reacts with 1-naphthol (NPL) in presence of oxidising agent potassium dichromate in acidic medium to produce red coloured product having λmax of 485 nm. The molar absorptivity and Sandell's sensitivity were 2.07x104 l mol-1 cm-1 and 0.00240 μg/cm2 respectively. The colour is stable for more than 6 h. The system obeys Beer's law in the range, 2-18 μg for determination of chromium (VI). The detection limits of chromium (VI) is 0.048 μg mL-1. The method is highly reproducible and has been applied to the analysis of chromium in synthetic, natural water samples and pharmaceutical preparations and the results compared favourably with the reported method