scholarly journals Facile and Low-Cost SPE Modification Towards Ultra-Sensitive Organophosphorus and Carbamate Pesticide Detection in Olive Oil

Molecules ◽  
2020 ◽  
Vol 25 (21) ◽  
pp. 4988
Author(s):  
Dionysios Soulis ◽  
Marianna Trigazi ◽  
George Tsekenis ◽  
Chrysoula Chandrinou ◽  
Apostolos Klinakis ◽  
...  
Keyword(s):  
Olive Oil ◽  
Limit Of Detection ◽  
Organophosphorus Pesticides ◽  
Low Cost ◽  
Linear Range ◽  
The Family ◽  
Forward Transfer ◽  
Optimized Conditions ◽  
Carbamate Pesticide

Despite the fact that a considerable amount of effort has been invested in the development of biosensors for the detection of pesticides, there is still a lack of a simple and low-cost platform that can reliably and sensitively detect their presence in real samples. Herein, an enzyme-based biosensor for the determination of both carbamate and organophosphorus pesticides is presented that is based on acetylcholinesterase (AChE) immobilized on commercially available screen-printed carbon electrodes (SPEs) modified with carbon black (CB), as a means to enhance their conductivity. Most interestingly, two different methodologies to deposit the enzyme onto the sensor surfaces were followed; strikingly different results were obtained depending on the family of pesticides under investigation. Furthermore, and towards the uniform application of the functionalization layer onto the SPEs’ surfaces, the laser induced forward transfer (LIFT) technique was employed in conjunction with CB functionalization, which allowed a considerable improvement of the sensor’s performance. Under the optimized conditions, the fabricated sensors can effectively detect carbofuran in a linear range from 1.1 × 10−9 to 2.3 × 10−8 mol/L, with a limit of detection equal to 0.6 × 10−9 mol/L and chlorpyrifos in a linear range from 0.7 × 10−9 up to 1.4 × 10−8 mol/L and a limit of detection 0.4 × 10−9 mol/L in buffer. The developed biosensor was also interrogated with olive oil samples, and was able to detect both pesticides at concentrations below 10 ppb, which is the maximum residue limit permitted by the European Food Safety Authority.

UV-Visible Spectrophotometric Determination of Lambda-Cyhalothrin Insecticide in Vegetables, Soil and Water Samples

2019 ◽  
Vol 31 (1) ◽  
pp. 1-9
Author(s):  
Deepak Kumar Sahu ◽  
Joyce Rai ◽  
Chhaya Bhatt ◽  
Manish K. Rai ◽  
Jyoti Goswami ◽  
...  
Keyword(s):  
Crop Production ◽  
Limit Of Detection ◽  
Low Cost ◽  
Molar Absorptivity ◽  
Agricultural Field ◽  
Limit Of Quantification ◽  
Yellow Colour ◽  
Modern Age ◽  
Lambda Cyhalothrin

In modern age pesticide is used widely in agriculture. Lambda-cyhalothrin (LCT) is one of the most used pesticides which are used as a insecticide to kill pest, tricks, flies etc in agricultural field and it is also used for crop production. We have developed new method to detect LCT insecticide in agriculture field and reduce its uses. In this method we found the maximum absorbance at 460 nm for yellow colour dye. We also calculated limit of detection and limit of quantification 0.001 mg kg-1 and 0.056 mg kg-1 respectively. Molar absorptivity and Sandell’s sensitivity was also calculated and obtained 1.782 ×107 mol-1 cm-1 and 9.996 ×10-6 µg cm-2 respectively. The obtained yellow colour dye obeyed Beer’s law limit range of 0.5 µg ml -1 to 16 µg ml-1 in 25 ml. This method is less time consuming, selective, simple, sensitive and low cost. Present method is successfully applied in various soil, water and vegetable samples.

scholarly journals Preparation of Cerium Oxide-MWCNTs Nanocomposite Bulk Modified Carbon Ceramic Electrode: A Sensitive Sensor for Tamoxifen Determination in Human Serum Samples

2021 ◽  
Author(s):  
Sepideh Shafaei ◽  
Elyas Hosseinzadeh ◽  
Gulsah Saydan Kanberoglu ◽  
Balal Khalilzadeh ◽  
Rahim Mohammad-Rezaei
Keyword(s):  
Cerium Oxide ◽  
Limit Of Detection ◽  
Low Cost ◽  
High Electron ◽  
Range Limit ◽  
Serum Samples ◽  
Important Species ◽  
Carbon Ceramic Electrode ◽  
Carbon Ceramic

Abstract In this study, cerium oxide and multi-walled carbon nanotubes nanocomposite was incorporated into the carbon ceramic electrode (CeO2-MWCNTs/CCE) as a renewable electrode for the electrocatalytic purposes. To demonstrate capability of the fabricated electrode, determination of Tamoxifen as an important anticancer drug with differential pulse voltammetry technique was evaluated. Linear range, limit of detection and sensitivity of the developed sensor were found to be 0.2-40 nM, 0.132 nM and 1.478 µA nM-1 cm-2, respectively. Ease of production, low cost and high electron transfer rate of CeO2-MWCNTs/CCE promise it as a novel electro-analytical tool for determination of important species in real samples.

scholarly journals Highly Selective, Aptamer-Based, Ultrasensitive Nanogold Colorimetric Smartphone Readout for Detection of Cd(II)

Molecules ◽  
2019 ◽  
Vol 24 (15) ◽  
pp. 2745 ◽  
Author(s):  
Lu Xu ◽  
Jun Liang ◽  
Yonghui Wang ◽  
Shuyue Ren ◽  
Jin Wu ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Low Cost ◽  
Quantitative Detection ◽  
Practical Application ◽  
Full Agreement ◽  
Experimental Conditions ◽  
Dose Time ◽  
Dimethyl Ammonium ◽  
Rice Samples ◽  
Optimized Conditions

A highly selective and sensitive method for Cd(II) detection was developed based on aptamer and gold nanoparticles (AuNPs) combined with a colorimetric smartphone readout. The experimental conditions such as reaction time of polydiene dimethyl ammonium chloride (PDDA) and AuNPs, PDDA dose, time of aptamer and PDDA incubation, and aptamer concentration were optimized. Under the optimized conditions, the color and red(R) value of the solution was concentration-dependent on Cd(II). The proposed method exhibited a linear range of 1–400 ng/mL (r2 = 0.9794) with a limit of detection (LOD) of 1 ng/mL. This method had been successfully applied to test and quantify Cd(II) in water and rice samples, and the results were in full agreement with those from the atomic absorption spectrometer. Therefore, low-cost colorimetry demonstrated its potential for practical application in visual or quantitative detection with a smartphone. This approach can be readily applied to other analytes.

Cloud Point Extraction and Spectrophotometry Determination of Lead in Environment Water Using 5-Br-PADAP

2013 ◽  
Vol 830 ◽  
pp. 345-348
Author(s):  
Lin Gao ◽  
Sheng Jie Chen ◽  
Fang Chen ◽  
Wen Hong Zhou ◽  
Jun Long Yao
Keyword(s):  
Cloud Point ◽  
Cloud Point Extraction ◽  
Detection Method ◽  
Low Cost ◽  
Calibration Graph ◽  
Buffer Solution ◽  
Relative Standard ◽  
Triton X ◽  
Optimized Conditions

A simple, sensitive, green and low cost detection method based on the cloud point extraction (CPE) separation and spectrophotometry was proposed for the determination of lead. In pH=9.0 H3BO3 buffer solution, Pb(II) reacts with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP) in the presence of Triton X-100 yielding a hydrophobic complex, which then is extracted into micro-volume surfactant-rich phase. The calibration graph was linear in the range of 20-400 µg/L (at 560 nm). Under the optimized conditions, the detection limits of 10.94 µg/L and the relative standard deviations(RSD) of 2.0% (n=5) for Lead(II) were found, respectively. The sensitivity and absorbance of this method are at least five times higher when compared with that of usual 5-Br-PADAP spectrophotometry without CPE, and the proposed method has been applied to the determination of Lead in environment water samples with satisfactory results.

scholarly journals Graphitic-Phase C3N4 Nanosheets Combined with MnO2 Nanosheets for Sensitive Fluorescence Quenching Detection of Parathion-Methyl

2021 ◽  
Author(s):  
Bicheng Liu ◽  
Sihao Wu ◽  
Zoujun Peng ◽  
Jiahan Rui ◽  
Ping Qiu
Keyword(s):  
Fluorescence Quenching ◽  
Limit Of Detection ◽  
Organophosphorus Pesticides ◽  
Cost Effective ◽  
Inner Filter Effect ◽  
Enzymatic Hydrolysate ◽  
Analytical Instruments ◽  
Dimethyl Phosphate ◽  
User Friendly

Abstract In this study, we have developed a sensitive approach to measure organophosphorus pesticides (OPs) using graphitic-phase C3N4 nanosheets (g-C3N4) combined with a nanomaterial-based quencher MnO2 nanosheets (MnO2 NS). Because MnO2 NS could quench the fluorescence of g-C3N4 via the inner-filter effect (IFE), the enzymatic hydrolysate (thiocholine, TCh) can efficiently trigger the decomposition of MnO2 nanosheets in the presence of acetylcholinesterase (AChE) and acetylthiocholine, resulting in the fluorescence recovery of g-C3N4. OPs, as inhibitors for AChE activity, can prevent the generation of TCh and decomposition of MnO2 nanosheets, accompanied by fluorescence quenching again. So the AChE-ATCh-MnO2-g-C3N4 system can be utilized to detect OPs quantitatively based on the g-C3N4 fluorescence. Under the optimum conditions, the linear range for the determination of parathion-methyl (PM) and 2,2-dichlorovinyl dimethyl phosphate (DDVP) were found in the range of 0.1-2.1 ng/mL with a limit of detection of 0.069 ng/mL, and 0.5-16 ng/mL with a limit of detection of 0.069 ng/mL, respectively. Finally, this method was exploited for the monitoring of PM in real samples. The advantages of the assay are user-friendly, easy-to-ease, cost-effective compared to sophisticated analytical instruments.

scholarly journals  Determination of CLINDAMYCIN HCl in Capsules by New, Validated, Simple and Green Kinetic Spectrometric Method

2021 ◽  
Author(s):  
Shaza Affas ◽  
Amir Alhaj Sakur
Keyword(s):  
Initial Rate ◽  
Limit Of Detection ◽  
Reference Method ◽  
Fixed Time ◽  
Spectrometric Method ◽  
Iodide Ions ◽  
Kinetic Spectrophotometric ◽  
Optimized Conditions ◽  
Good Agreement

Abstract Background: simple, sensitive, free of organic solvents, kinetic spectrophotometric method has been developed for the determination of Clindamycin Hydrochloride, both in pure form and Capsules. Method used is based on reaction of Clindamycin with potassium iodide and potassium iodate in aqueous medium at (25 ±2 °c) to produce yellow colored tri iodide ions (I3-). the reaction is followed spectrophotometrically by measuring the absorbance at 350 nm wavelength during 40 minutes. Results: the effects of analytical parameters on reported kinetic methods were investigated. Under the optimized conditions, the initial rate and fixed time (at 10 min) methods were used for constructing the calibration graphs. The graphs were linear in concentration ranges 1-20 μg.ml-1 with limit of detection of 0.12 and 0.22 μg ml-1for the initial rate and fixed time methods, respectively. The results were satisfactory and the analytical performance for both methods was validated. Conclusion: The proposed methods have been applied to determine the components in capsules with an average recovery of 98.25% to 102.00% and the results are in good agreement with those found by the reference method.

scholarly journals Development of a Nanocluster-Based Platform for Determination of Sofosbuvir

2021 ◽  
Author(s):  
Zahra Karimzadeh ◽  
Abolghasem Jouyban ◽  
Elaheh Rahimpour
Keyword(s):  
Response Surface Methodology ◽  
Limit Of Detection ◽  
Copper Nitrate ◽  
Plasma Samples ◽  
Copper Nanoclusters ◽  
Good Repeatability ◽  
Direct Acting ◽  
Optimized Conditions ◽  
Linear Concentration

Background: Sofosbuvir is a potent direct-acting antivirus agent that has been listed as a promising medicine for the treatment of all genotypes of hepatitis C virus. As antiviral drugs could be metabolized to their associated compounds and toxicologically and pharmacologically interfere with the parent drugs, identifying the therapeutic range of drugs would be notable. Methods: In the current study, copper nanoclusters (Cu NCs) are synthesized during the reduction of copper nitrate with hydrazine hydrate in a protected media and used as a nanoprobe for the determination of sofosbuvir in plasma samples. Herein, synchronous fluorescence spectroscopy (SFS) is used for monitoring of fluorescence variation of nanoprobe owing to the excessive benefits compared with the traditional fluorescence. Results: SFS peak of Cu NCs has appeared at 355 nm with ∆λ=80 nm which is decreased in the presence of sofosbuvir. To optimize the reaction factors, a response surface methodology is used and in the optimized conditions, a linear concentration-response plot is obtained in a range of 0.05-6.0 µg mL−1 with a limit of detection of 0.0147 µg mL−1. Conclusion: The developed method also reveals good repeatability and selectivity for sofosbuvir in plasma samples.

scholarly journals Characterization of handmade Nepali paper as a platform for paper analytical device to determine anti-diabetic drug

2021 ◽  
Author(s):  
Ram Bhattarai ◽  
Sanam Pudasaini ◽  
Mukesh Sah ◽  
Bhanu Neupane ◽  
Basant Giri
Keyword(s):  
Limit Of Detection ◽  
Low Cost ◽  
Water Contact ◽  
Regulatory Standards ◽  
Three Samples ◽  
Limit Of Quantitation ◽  
Metformin Concentration ◽  
Analytical Device

The COVID-19 pandemic has highlighted the need of eco-friendly and locally or distributed manufacturing of diagnostic and safety products. Here, we characterized five handmade papers for their potential application to make paper analytical device (PADs). The handmade papers were made from locally available plant fiber using eco-friendly method. Thickness, grammage, and apparent density of the paper samples ranged from 198 μm to 314 μm, 49 g/m2 to 117.8 g/m2, and 0.23 to 0.39 g/cm3, respectively. Moisture content, water filtration and wicking speed ranged from 5.2% to 7.1%, 35.7 to 156.7, and 0.062 to 0.124 mms-1, respectively. Further, water contact angle and porosity ranged from 76˚ to 112˚ and 79% to 83%, respectively. The best paper sample one was chosen to fabricate PADs which were used for the determination of metformin. The metformin assay on PADs followed linear range from 0.0625 to 0.5 mg/mL. The assay had limit of detection and limit of quantitation of 0.05 mg/mL and 0.18 mg/mL respectively. The new method was used to test metformin samples (n=20) collected from local pharmacies. The average amount of metformin concentration in samples was 465.6 ± 15.1mg/tablet. Three samples did not meet the regulatory standards. When compared with spectrophotometric method, PADs assay correctly predicted 18 out of 20 samples. The PADs assay on handmade paper may provide a low-cost and easy-to-use system to screening the quality of drugs and other point-of-need applications.

scholarly journals Food Analysis: Task specific ionic liquids for separation of nickel and cadmium from olive oil samples by thermal ultrasound-assisted dispersive multiphasic microextraction

2019 ◽  
Vol 2 (2) ◽  
pp. 55-64 ◽  
Author(s):  
Asian Khaligh ◽  
Hamid Shirkhanloo
Keyword(s):  
Olive Oil ◽  
Limit Of Detection ◽  
Hydroxycinnamic Acid ◽  
Extraction And Separation ◽  
Analysis Task ◽  
Highly Sensitive ◽  
Ultrasound Assisted ◽  
Optimized Conditions ◽  
Extracting Solvent ◽  
Task Specific Ionic Liquid

A novel task-specific ionic liquid (TSILs) was used for highly sensitive extraction and separation of nickel and cadmium in olive oil by thermal ultrasound-assisted dispersive multiphasic microextraction (TUSA-DMPμE). By proposed method, a mixture containing of hydrophilic TSILs (α- Cyano-4-hydroxycinnamic acid diethylamine; [CHCA] [DEA] and 1-(2-Hydroxyethyl)-3-methylimidazolium tetrafluoroborate; [HEMIM][BF4]) as a complexing and extracting solvent, acetone as a dispersant of TSILs was added to diluted olive oil with n-hexane containing Cd (II) and Ni (II) that was already complexed by TSILs in 60OC at pH 6.0-7.5. After optimized conditions, the enrichment factor (EF), Linear range (LR) and limit of detection (LOD) were obtained (19.3; 19.6), (5.0- 415 μg L-1; 2.7- 92 μg L-1) and (1.3 μg L-1;  0.6 μg L-1) with [CHCA] [DEA] and (13.7; 14.2), (7.5- 600 μg L-1; 3.6- 128 μg L-1) and (2.2 ng L-1; 0.9 μg L-1) with [HEMIM][BF4] for Ni and Cd ions in olive  samples respectively.

scholarly journals Paracetamol Sensing with a Pencil Lead Electrode Modified with Carbon Nanotubes and Polyvinylpyrrolidone

Chemosensors ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 133
Author(s):  
Piyanut Pinyou ◽  
Vincent Blay ◽  
Kantapat Chansaenpak ◽  
Sireerat Lisnund
Keyword(s):  
Carbon Nanotubes ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Low Cost ◽  
Electrical Contact ◽  
Pharmaceutical Preparations ◽  
Single Wall Carbon Nanotubes ◽  
Wave Voltammetry ◽  
Lead Electrode

The determination of paracetamol is a common need in pharmaceutical and environmental samples for which a low-cost, rapid, and accurate sensor would be highly desirable. We develop a novel pencil graphite lead electrode (PGE) modified with single-wall carbon nanotubes (SWCNTs) and polyvinylpyrrolidone (PVP) polymer (PVP/SWCNT/PGE) for the voltammetric quantification of paracetamol. The sensor shows remarkable analytical performance in the determination of paracetamol at neutral pH, with a limit of detection of 0.38 μM and a linear response from 1 to 500 μM using square-wave voltammetry (SWV), which are well suited to the analysis of pharmaceutical preparations. The introduction of the polymer PVP can cause dramatic changes in the sensing performance of the electrode, depending on its specific architecture. These effects were investigated using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM). The results indicate that the co-localization and dispersion of PVP throughout the carbon nanotubes on the electrode are key to its superior electrochemical performance, facilitating the electrical contact between the nanotubes and with the electrode surface. The application of this sensor to commercial syrup and tablet preparations is demonstrated with excellent results.

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