scholarly journals Paper Strip and Ceramic Potentiometric Platforms Modified with Nano-Sized Polyaniline (PANi) for Static and Hydrodynamic Monitoring of Chromium in Industrial Samples

Molecules ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 629
Author(s):  
Saad S. M. Hassan ◽  
Ayman H. Kamel ◽  
Abd El-Galil E. Amr ◽  
M. Abdelwahab Fathy ◽  
Mohamed A. Al-Omar
Keyword(s):  
Limit Of Detection ◽  
Water Layer ◽  
Absorption Spectrometry ◽  
Potentiometric Sensors ◽  
Pani Film ◽  
Paper Strip ◽  
Buffer Solution ◽  
Total Chromium ◽  
Potentiometric Response ◽  
Inorganic Species

Screen-printed membrane sensors based on the use of paper and ceramic substrates are fabricated, characterized, and used for rapid batch and continuous monitoring of CrIII in the form of CrO42− in some industrial products and wastewater samples. Strips of paper and ceramic platforms (15 × 5 mm) were covered with conductive carbon paint and then modified with polyaniline (PANI) film, to act as an ion-to-electron transducer, followed by a drop casting of plasticized poly (vinyl chloride) (PVC) Rhodamine-B chromate membrane as a recognition sensing material. In a 5.0 mmol L−1 Trizma buffer solution of pH ~8, the fabricated paper and ceramic based membrane sensors exhibited a near Nernstian response for CrVI ion with slopes of −29.7 ± 0.5 and −28.6 ± 0.3 mV decade−1, limit of detection 2.5 × 10−5 and 2.4 × 10−6 mol L−1 (1.3–0.12 µg mL−1), and linear concentration range 7.5 × 10−3–5.0 × 10−5 and 7.5 × 10−3–1.0 × 10−5 mol L−1 (390-0.5 µg mL−1), respectively. Both sensors exhibited fast and stable potentiometric response, excellent reproducibility, and good selectivity with respect to a number of common foreign inorganic species. Impedance spectroscopy and chronopotentiometry data revealed a small resistance and a larger double layer capacitance due to the presence of the intermediate polyaniline (PAN) conductive layer. Furthermore, the formation of a water layer between the ion selective membrane (ISM) and the underlying conductor polymer and between the conducting polymer and the carbon conducting surface was greatly reduced. The developed disposable solid-contact potentiometric sensors offer the advantages of simple design, long term potential stability, flexibility, miniaturization ability, short conditioning time, and cost effectiveness that enable mass production. The sensors were successfully used for static and hydrodynamic measurements of total chromium in some leather tanning wastewater and nickel-chrome alloy samples. The results compare favorably with data obtained by atomic absorption spectrometry.

scholarly journals Modified Screen-Printed Potentiometric Sensors based on Man-Tailored Biomimetics for Diquat Herbicide Determination

2020 ◽  
Vol 17 (4) ◽  
pp. 1138
Author(s):  
Ayman H. Kamel ◽  
Abd El-Galil E. Amr ◽  
Nashwa S. Abdalla ◽  
Mohamed El-Naggar ◽  
Mohamed A. Al-Omar ◽  
...  
Keyword(s):  
Molecularly Imprinted Polymers ◽  
Limit Of Detection ◽  
Water Layer ◽  
Charge Transfer Resistance ◽  
Potentiometric Sensors ◽  
Layer Potential ◽  
Transfer Resistance ◽  
Commercial Pesticide ◽  
Ph Range ◽  
Screen Printed

Screen-printed platforms integrated with molecularly imprinted polymers (MIP) were fabricated and characterized as potentiometric sensors for diquat (DQ). The synthesized MIP beads were studied as sensory carriers in plasticized poly(vinyl chloride) membranes. The sensors were constructed by using poly(3,4-ethylenedioxythiophene) (PEDOT) as solid-contact material to diminish charge-transfer resistance and water layer potential. Conventional ion-selective electrodes (ISEs) with internal filling solution were used for comparison. The designed electrodes showed near Nernstian slopes of 28.2 ± 0.7 (r² = 0.999) over the concentration range of 1.0 × 10−6–1.0 × 10−2 M with the limit of detection 0.026 µg/mL over the pH range 4.2–9.0. The electrode exhibited good selectivity for diquat cations over a large number of organic and inorganic cations. The sensor was successfully introduced for direct measurement of diquat content in commercial pesticide preparations and different spiked potato samples. The results showed that the proposed electrode has a fast and stable response, good reproducibility, and applicability for direct assessment of diquat content. The proposed potentiometric method is simple and accurate in comparison with the reported HPLC methods. Besides, it is applicable to turbid and colored sample solutions.

scholarly journals An Improved Methodology for Determination of Fluorine in Biological Samples Using High-Resolution Molecular Absorption Spectrometry via Gallium Fluorine Formation in a Graphite Furnace

2021 ◽  
Vol 11 (12) ◽  
pp. 5493
Author(s):  
Andrzej Gawor ◽  
Andrii Tupys ◽  
Anna Ruszczyńska ◽  
Ewa Bulska
Keyword(s):  
High Resolution ◽  
Limit Of Detection ◽  
Graphite Furnace ◽  
Absorption Spectrometry ◽  
Biological Tissues ◽  
Biologically Active ◽  
Molecular Absorption ◽  
Biological Origin ◽  
Molecular Absorption Spectrometry

Nowadays growing attention is paid to the control of fluorine content in samples of biological origin as it is present in the form of various biologically active organic compounds. Due to the chemically-rich matrix of biological tissues, the determination of fluorine becomes a very difficult task. Furthermore, a required complex sample preparation procedure makes the determination of the low contents of F by ion chromatography UV-Vis or ion-selective electrodes not possible. High-resolution continuum source graphite furnace molecular absorption spectrometry (HR-CS GF MAS) seems to be the best option for this purpose due to its high robustness to matrix interferences, especially in the presence of carefully selected modifiers. In this work the possibility of quantitative F determination in water and animal tissues was examined by measuring the molecular absorption of gallium monofluoride (GaF) at 211.248 nm with the use of a commercially available HR-CS GF MAS system. Experimental conditions for the sensitive and precise determination of fluorine were optimized, including the time/temperature program as well as addition of gallium and modifier mixture in combined mode. Under these conditions the fluoride present in the sample was stabilized up to 600 °C, and the optimum vaporization temperature for GaF was 1540 °C. Palladium and zirconium deposited onto the graphite surface served as solid modifiers; sodium acetate and ruthenium modifiers were added directly to the sample. The limit of detection and the characteristic mass of the method were 0.43 μg/L and 8.7 pg, respectively. The proposed procedure was validated by the use of certified reference materials (CRMs) of lake water and animal tissue; the acceptable recovery was obtained, proving that it can be applied for samples with a similar matrix.

scholarly journals Simultaneous electrochemical sensing of dihydroxy benzene isomers at cost-effective allura red polymeric film modified glassy carbon electrode

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Pattan-Siddappa Ganesh ◽  
Ganesh Shimoga ◽  
Seok-Han Lee ◽  
Sang-Youn Kim ◽  
Eno E. Ebenso
Keyword(s):  
Glassy Carbon Electrode ◽  
Glassy Carbon ◽  
Limit Of Detection ◽  
Tap Water ◽  
Differential Pulse ◽  
Oxidation Potential ◽  
Electrochemical Sensing ◽  
Carbon Electrode ◽  
Buffer Solution ◽  
Allura Red

Abstract Background A simple and simultaneous electrochemical sensing platform was fabricated by electropolymerization of allura red on glassy carbon electrode (GCE) for the interference-free detection of dihydroxy benzene isomers. Methods The modified working electrode was characterized by electrochemical and field emission scanning electron microscopy methods. The modified electrode showed excellent electrocatalytic activity for the electrooxidation of catechol (CC) and hydroquinone (HQ) at physiological pH of 7.4 by cyclic voltammetric (CV) and differential pulse voltammetric (DPV) techniques. Results The effective split in the overlapped oxidation signal of CC and HQ was achieved in a binary mixture with peak to peak separation of 0.102 V and 0.103 V by CV and DPV techniques. The electrode kinetics was found to be adsorption-controlled. The oxidation potential directly depends on the pH of the buffer solution, and it witnessed the transfer of equal number of protons and electrons in the redox phenomenon. Conclusions The limit of detection (LOD) for CC and HQ was calculated to be 0.126 μM and 0.132 μM in the linear range of 0 to 80.0 μM and 0 to 110.0 μM, respectively, by ultra-sensitive DPV technique. The practical applicability of the proposed sensor was evaluated for tap water sample analysis, and good recovery rates were observed. Graphical abstract Electrocatalytic interaction of ALR/GCE with dihydroxy benzene isomers.

scholarly journals Electro-Polymerized Titan Yellow Modified Carbon Paste Electrode for the Analysis of Curcumin

Surfaces ◽  
2021 ◽  
Vol 4 (3) ◽  
pp. 191-204
Author(s):  
Edwin S. D’Souza ◽  
Jamballi G. Manjunatha ◽  
Chenthattil Raril ◽  
Girish Tigari ◽  
Huligerepura J. Arpitha ◽  
...  
Keyword(s):  
Carbon Paste Electrode ◽  
Limit Of Detection ◽  
Phosphate Buffer Solution ◽  
Modified Carbon Paste Electrode ◽  
Carbon Paste ◽  
Buffer Solution ◽  
Solution Ph ◽  
Real Sample Analysis ◽  
Titan Yellow ◽  
Paste Electrode

A modest, efficient, and sensitive chemically modified electrode was fabricated for sensing curcumin (CRC) through an electrochemically polymerized titan yellow (TY) modified carbon paste electrode (PTYMCPE) in phosphate buffer solution (pH 7.0). Cyclic voltammetry (CV) linear sweep voltammetry (LSV) and differential pulse voltammetry (DPV) approaches were used for CRC detection. PTYMCPE interaction with CRC suggests that the electrode exhibits admirable electrochemical response as compared to bare carbon paste electrode (BCPE). Under the optimized circumstances, a linear response of the electrode was observed for CRC in the concentration range 2 × 10−6 M to 10 × 10−6 M with a limit of detection (LOD) of 10.94 × 10−7 M. Moreover, the effort explains that the PTYMCPE electrode has a hopeful approach for the electrochemical resolution of biologically significant compounds. Additionally, the proposed electrode has demonstrated many advantages such as easy preparation, elevated sensitivity, stability, and enhanced catalytic activity, and can be successfully applied in real sample analysis.

scholarly journals Determination of cobalt in water samples by atomic absorption spectrometry after pre-concentration with a simple ionic liquid-based dispersive liquid-liquid micro-extraction methodology

2010 ◽  
Vol 8 (3) ◽  
pp. 617-625 ◽  
Author(s):  
Hossein Abdolmohammad-Zadeh ◽  
Elnaz Ebrahimzadeh
Keyword(s):  
Ionic Liquid ◽  
Atomic Absorption Spectrometry ◽  
Atomic Absorption ◽  
Water Samples ◽  
Limit Of Detection ◽  
Absorption Spectrometry ◽  
Experimental Conditions ◽  
Flame Atomic Absorption ◽  
Relative Standard

AbstractA rapid dispersive liquid-liquid micro-extraction (DLLME) methodology based on the application of 1-hexylpyridinium hexafluorophosphate [C6py][PF6] ionic liquid (IL) as an extractant solvent was applied for the pre-concentration of trace levels of cobalt prior to determination by flame atomic absorption spectrometry (FAAS). 1-Phenyl-3-methyl-4-benzoyl-5-pyrazolone (PMBP) was employed as a chelator forming a Co-PMBP complex to extract cobalt ions from aqueous solution into the fine droplets of [C6py][PF6]. Some effective factors that influence the micro-extraction efficiency include the pH, the PMBP concentration, the amount of ionic liquid, the ionic strength, the temperature and the centrifugation time which were investigated and optimized. In the optimum experimental conditions, the limit of detection (3s) and the enrichment factor were 0.70 µg L−1 and 60, respectively. The relative standard deviation (RSD) for six replicate determinations of 50 µg L−1 Co was 2.36%. The calibration graph using the pre-concentration system was linear at levels 2–166 µg L−1 with a correlation coefficient of 0.9982. The applicability of the proposed method was evaluated by the determination of trace amounts of cobalt in several water samples.

scholarly journals Cloud point extraction and preconcentration of gold in geological matrices prior to flame atomic absorption determination

2010 ◽  
Vol 8 (1) ◽  
pp. 34-40 ◽  
Author(s):  
Wifky El-Naggar ◽  
Taysseer Lasheen ◽  
El-Said Nouh ◽  
Ahmed Ghonaim
Keyword(s):  
Atomic Absorption ◽  
Cloud Point ◽  
Cloud Point Extraction ◽  
Limit Of Detection ◽  
Absorption Spectrometry ◽  
Complexing Agent ◽  
Rich Phase ◽  
Flame Atomic Absorption ◽  
Initial Aqueous Solution ◽  
Triton X

AbstractBrilliant green was used as a complexing agent in cloud point extraction (CPE) and applied for selective preconcentration of trace amounts of gold in geological matrices. The analyte in the initial aqueous solution was acidified with hydrochloric acid (0.1 M) and octylphenoxypolyethoxyethanol (Triton X-114) was added as a surfactant. After phase separation, based on the cloud point separation of the mixture, the surfactant rich phase was diluted with methanol and the analyte determined in the surfactant rich phase by flame atomic absorption spectrometry (FAAS). After optimization of the complexation and extraction conditions, a preconcentration factor of 31 was obtained for only 10 mL of sample. The analytical curve was linear in the range of 3–1000 ng mL−1 and the limit of detection was 1.5 ng mL−1. The proposed method was applied to the determination of gold in geological samples.

Fabrication of an Electrochemical Sensor for Glucose Detection using ZnO Nanorods

MRS Advances ◽  
2016 ◽  
Vol 1 (13) ◽  
pp. 861-867 ◽  
Author(s):  
Sanghamitra Mandal ◽  
Mohammed Marie ◽  
Omar Manasreh
Keyword(s):  
Response Time ◽  
Glass Substrate ◽  
Glucose Sensor ◽  
Limit Of Detection ◽  
Sol Gel ◽  
Zno Nanorods ◽  
Phosphate Buffer Solution ◽  
Buffer Solution ◽  
Coated Glass Substrate ◽  
Coated Glass

ABSTRACTAn electrochemical glucose sensor based on zinc oxide (ZnO) nanorods is fabricated, characterized and tested. The ZnO nanorods are synthesized on indium titanium oxide (ITO) coated glass substrate, using the hydrothermal sol-gel technique. The working principle of the sensor under investigation is based on the electrochemical reaction taking place between cathode and anode, in the presence of an electrolyte. A platinum plate, used as the cathode and Nafion/Glucose Oxidase/ZnO nanorods/ITO-coated glass substrate used as anode, is immersed in pH 7.0 phosphate buffer solution electrolyte to test for the presence of glucose. Several amperometric tests are performed on the fabricated sensor to determine the response time, sensitivity and limit of detection of the sensor. A fast response time less than 3 s with a high sensitivity of 1.151 mA cm-2mM-1 and low limit of detection of 0.089 mM is reported. The glucose sensor is characterized using the cyclic voltammetry method in the range from -0.8 – 0.8 V with a voltage scan rate of 100 mV/s.

Modern Methodological Approaches to Sample Preparation for the Determination of Trace Elements in Food Products and Plant Raw Materials

2021 ◽  
pp. 48-54
Author(s):  
NE Fedorova ◽  
MV Egorova ◽  
AS Rodionov
Keyword(s):  
High Resolution ◽  
Sample Preparation ◽  
Atomic Absorption Spectrometry ◽  
Atomic Absorption ◽  
Flame Atomic Absorption Spectrometry ◽  
Limit Of Detection ◽  
Absorption Spectrometry ◽  
Flame Atomic Absorption ◽  
Homogeneity Of Variances ◽  
Limit Of Quantitation

Introduction. Various copper compounds are most widely used as plant protection agents in agriculture. From a hygienic point of view, information on excessive accumulation of copper in plants related to the use of a specific formulation of copper-containing pesticides is of interest. Our objective was to assess feasibility of increasing statistical significance of results of determining low residue levels of a copper-containing pesticide in apple samples by flame atomic absorption spectrometry using a high-resolution spectrometer in combination with developed approaches to sample preparation of plant-based foods, including homogenization with dry ice and microwave mineralization. Materials and methods: We analyzed 30 samples of apples collected in three different agro-climatic zones by flame atomic absorption spectrometry and electrothermal atomization atomic absorption spectrometry. Both methods were validated on 10 samples with added copper at levels 1-5 of the lower limit of quantitation. A statistical calculation was performed based on a simple Student’s test to assess the significance of differences between the results of measurements by flame and electrothermal techniques. Homogeneity of variances was estimated using the Fisher test to clarify the possibility of comparing two data sets. Results: The use of a technique of cryo-grinding and microwave decomposition in a microwave reactor in combination with a high-resolution continuum source atomic absorption spectrometry demonstrated a decrease in scattering and the limit of detection and better repeatability in the analysis of parallel samples. Results of statistical calculations confirmed the homogeneity of variances in data samples obtained for electrothermal and flame techniques, and the further Student’s t-test showed insignificant differences between the results of measurements obtained by FAAS and ET-AAS. Conclusion: Our findings prove that modern methods of sample preparation in combination with highly sensitive equipment allow a significant reduction in the limit of detection and scattering of test results.

scholarly journals Potentiometric Sensors for Iodide and Bromide Based on Pt(II)-Porphyrin

Sensors ◽  
2018 ◽  
Vol 18 (7) ◽  
pp. 2297 ◽  
Author(s):  
Dana Vlascici ◽  
Nicoleta Plesu ◽  
Gheorghe Fagadar-Cosma ◽  
Anca Lascu ◽  
Mihaela Petric ◽  
...  
Keyword(s):  
Diffusion Coefficient ◽  
Water Absorption ◽  
Vinyl Chloride ◽  
Potentiometric Sensors ◽  
Iodide Ions ◽  
Response Characteristics ◽  
Potentiometric Response ◽  
Poly Vinyl Chloride

Pt(II) 5,10,15,20-tetra(4-methoxy-phenyl)-porphyrin (PtTMeOPP) was used in the construction of new ion-selective sensors. The potentiometric response characteristics (slope and selectivity) of iodide and bromide-selective electrodes based on (PtTMeOPP) metalloporphyrin in o-nitrophenyloctylether (NPOE), dioctylphtalate (DOP) and dioctylsebacate (DOS) plasticized poly(vinyl chloride) membranes are compared. The best results were obtained for the membranes plasticized with DOP and NPOE. The sensors have linear responses with near-Nernstian slopes toward bromide and iodide ions and good selectivity. The membrane plasticized with NPOE was electrochemically characterized using the EIS method to determine its water absorption and the diffusion coefficient into the membrane.

scholarly journals Determination of Chromium in Biological Material by Electrothermal Atomic Absorption Spectrometry Method

2012 ◽  
Vol 56 (4) ◽  
pp. 585-589 ◽  
Author(s):  
Agnieszka Nawrocka ◽  
Józef Szkoda
Keyword(s):  
Atomic Absorption Spectrometry ◽  
Atomic Absorption ◽  
Certified Reference Materials ◽  
Graphite Furnace ◽  
Electrothermal Atomic Absorption Spectrometry ◽  
Absorption Spectrometry ◽  
Magnesium Nitrate ◽  
Spectrometry Method ◽  
Total Chromium

Abstract Procedure for determination of chromium in biological materials by Zeeman graphite furnace atomic absorption spectrometry method using a Perkin-Elmer spectrometer equipped with hollow-cathode lamp at 357.9 nm was developed. The samples of animal tissues, food, and feed were digested in muffle furnace at 450ºC. The ash was dissolved in 1 N hydrochloric acid and the final solution was diluted in 0.2% nitric acid. Magnesium nitrate (1%) was used as a matrix modifier. The method was validated in terms of basic analytical parameters. The mean recoveries of chromium was 84.4% for muscle, 79.0% for canned meat, and 80.2% for feed, and analytical detection limit was 0.003 μg/g. Certified reference materials were used for analytical quality assurance. The proposed analytical procedure is well adapted for monitoring chromium content in food and feedstuffs. Content of total chromium in the tested samples (animal muscles and liver) was low and was situated in the range of 0.031-0.101 mg/kg (muscles) and 0.047-0.052 mg/kg (liver).

Sign in / Sign up

Export Citation Format

Share Document