Electrochemical Sensor Based on Nanodiamonds and Manioc Starch for Detection of Tetracycline

The use of nanostructured materials is already well-known as a powerful tool in the development of electrochemical sensors. Among several immobilization strategies of nanomaterials in the development of electrochemical sensors, the use of low-cost and environmentally friendly polymeric materials is highlighted. In this context, a new nanostructured biocomposite electrode is proposed as an electrochemical sensor for the analysis and determination of tetracycline. The composite electrode consists of a modified glassy carbon electrode (GCE) with a nanodiamond-based (ND) and manioc starch biofilm (MS), called ND-MS/GCE. The proposed sensor showed better electrochemical performance in the presence of tetracycline in comparison to the unmodified electrode, which was attributed to the increase in the electroactive surface area due to the presence of nanodiamonds. A linear dynamic range from 5.0 × 10 − 6 to 1.8 × 10 − 4 mol L−1 and a limit of detection of 2.0 × 10 − 6 mol L−1 were obtained for the proposed sensor. ND-MS/GCE exhibited high repeatability and reproducibility for successive measurements with a relative standard deviation (RSD) of 6.3% and 1.5%, respectively. The proposed electrode was successfully applied for the detection of tetracycline in different kinds of water samples, presenting recoveries ranging from 86 to 112%.

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Research developments in carbon materials based sensors for determination of hormones

Journal of Electrochemical Science and Engineering ◽

10.5599/jese.1094 ◽

2021 ◽

Author(s):

Jamballi G. Manjunatha ◽

Girish Tigari ◽

Hareesha Nagarajappa ◽

Nambudumada S. Prinith

Keyword(s):

Carbon Materials ◽

Electrochemical Sensors ◽

Electrochemical Impedance ◽

Limit Of Detection ◽

Supporting Electrolyte ◽

Electroanalytical Methods ◽

Repeatability And Reproducibility ◽

Electrochemical Impedance Spectroscopic ◽

Structural Aspects

Various carbon-based sensors (graphene, carbon nanotubes, graphite, pencil graphite, glassy carbon, etc.) have distinctive behavior and a broad range of importance for identifying sex hormones like estriol, estradiol, estrone, progesterone, and testosterone. The current review emphasizes voltammetric, amperometric, and electrochemical impedance spectroscopic methods for detecting some of these hormones. The existence, structural aspects, nature, and biological importance of each hormone were analyzed in detail and their analysis with different electroanalytical methods was considered. Unique methodologies and innovations of electrochemical sensors for hormones based on carbon materials modified by different agents were examined. In this review, the interaction among various sensor materials and analytes in different supporting electrolyte media is premeditated. The most important significances of the electroanalytical methodologies were discussed based on sensor selectivity, sensitivity, stability, the limit of detection, repeatability, and reproducibility.

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Miniaturized Fluorimetric Method for Quantification of Zinc in Dry Dog Food

Journal of Analytical Methods in Chemistry ◽

10.1155/2020/8821809 ◽

2020 ◽

Vol 2020 ◽

pp. 1-6

Author(s):

Rute C. Martins ◽

Ana M. Pereira ◽

Elisabete Matos ◽

Luisa Barreiros ◽

António J. M. Fonseca ◽

...

Keyword(s):

Limit Of Detection ◽

Rapid Determination ◽

Low Cost ◽

Food Samples ◽

Dog Food ◽

Fluorimetric Assay ◽

Relative Standard ◽

The Stability ◽

Cost Determination

Zinc is an essential trace element for animals in several biological processes, particularly in energy production, and it is acquired from food ingestion. In this context, a microplate-based fluorimetric assay was developed for simple, fast, and low-cost determination of zinc in pet food using 2,2′-((4-(2,7-difluoro-3,6-dihydroxy-4aH-xanthen-9-yl)-3-methoxyphenyl)azanediyl)diacetic acid (FluoZin-1) as fluorescent probe. Several aspects were studied, namely, the stability of the fluorescent product over time, the FluoZin-1 concentration, and the pH of reaction media. The developed methodology provided a limit of detection of 1 μg L−1 in sample acid digests, with a working range of 10 to 200 μg L−1, corresponding to 100–2000 mg of Zn per kg of dry dog food samples. Intraday repeatability and interday repeatability were assessed, with relative standard deviation values < 3.4% (100 μg L−1) and <11.7% (10 μg L−1). Sample analysis indicated that the proposed fluorimetric assay provided results consistent with ICP-MS analysis. These results demonstrated that the developed assay can be used for rapid determination of zinc in dry dog food.

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Electrochemical Sensors Based on Conducting Polymers for the Aqueous Detection of Biologically Relevant Molecules

Nanomaterials ◽

10.3390/nano11010252 ◽

2021 ◽

Vol 11 (1) ◽

pp. 252

Author(s):

Álvaro Terán-Alcocer ◽

Francisco Bravo-Plascencia ◽

Carlos Cevallos-Morillo ◽

Alex Palma-Cando

Keyword(s):

Conducting Polymers ◽

Building Materials ◽

Electrochemical Sensors ◽

Limit Of Detection ◽

Low Cost ◽

Relevant Literature ◽

Liquid Solution ◽

Morphological Characterization ◽

Special Focus

Electrochemical sensors appear as low-cost, rapid, easy to use, and in situ devices for determination of diverse analytes in a liquid solution. In that context, conducting polymers are much-explored sensor building materials because of their semiconductivity, structural versatility, multiple synthetic pathways, and stability in environmental conditions. In this state-of-the-art review, synthetic processes, morphological characterization, and nanostructure formation are analyzed for relevant literature about electrochemical sensors based on conducting polymers for the determination of molecules that (i) have a fundamental role in the human body function regulation, and (ii) are considered as water emergent pollutants. Special focus is put on the different types of micro- and nanostructures generated for the polymer itself or the combination with different materials in a composite, and how the rough morphology of the conducting polymers based electrochemical sensors affect their limit of detection. Polypyrroles, polyanilines, and polythiophenes appear as the most recurrent conducting polymers for the construction of electrochemical sensors. These conducting polymers are usually built starting from bifunctional precursor monomers resulting in linear and branched polymer structures; however, opportunities for sensitivity enhancement in electrochemical sensors have been recently reported by using conjugated microporous polymers synthesized from multifunctional monomers.

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Determination of four naphthalenediols in cosmetic samples by sweeping-micellar electrokinetic chromatography and a comparison with HPLC

Acta Chromatographica ◽

10.1556/1326.2021.00942 ◽

2021 ◽

Author(s):

Qian Wang ◽

Xiaobin Li ◽

Zhihan Zheng ◽

Huitao Liu ◽

Yuan Gao

Keyword(s):

Micellar Electrokinetic Chromatography ◽

Limit Of Detection ◽

Low Cost ◽

Hplc Method ◽

National Standards ◽

Sample Introduction ◽

Electrokinetic Chromatography ◽

Relative Standard ◽

Limit Of Quantitation

Abstract A sweeping micellar electrokinetic chromatography (sweeping-MEKC) method was developed for the determination of 1,7-naphthalenediol, 2,3-naphthalenediol, 1,5-naphthalenediol and 2,7-naphthalenediol in cosmetics. Several parameters affecting sweeping-MEKC method were studied systematically and the separation conditions were optimized as 20 mM NaH2PO4–110 mM SDS and 40% (v/v) MeOH (pH 2.4), with −22 kV applied voltage and UV detection at 230 nm. The sample matrix is 60 mmol L−1 NaH2PO4 and sample introduction was performed at 3 psi for 6 s. Separation of the four naphthalenediols was completed in less than 17 min. Limit of detection (LOD) and limit of quantitation (LOQ) are 0.0045∼0.0094 μg mL−1 and 0.015∼0.031 μg mL−1. Linear relationship (r 2 > 0.999) is satisfactory at the range of 0.1–10 μg mL−1. The developed method has been successfully applied to the determination of the four naphthalenediols in real cosmetic samples, with recoveries in foundation, sun cream and lotion in the range of 92.3%∼106.8% and relative standard deviation (RSD) less than 4.15%. A HPLC method described in the National Standards of the People’s Republic of China was carried out for the comparison with the proposed method. The results showed that the proposed sweeping-MEKC method has the advantages of fast, low cost with comparative sensitivity.

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Determination of Trace Levels of Nickel(II) by Adsorptive Stripping Voltammetry Using a Disposable and Low-Cost Carbon Screen-Printed Electrode

Chemosensors ◽

10.3390/chemosensors9050094 ◽

2021 ◽

Vol 9 (5) ◽

pp. 94

Author(s):

Víctor Padilla ◽

Núria Serrano ◽

José Manuel Díaz-Cruz

Keyword(s):

Limit Of Detection ◽

Low Cost ◽

Stripping Voltammetry ◽

Differential Pulse ◽

Adsorptive Stripping Voltammetry ◽

Carbon Surface ◽

Complexing Agent ◽

Relative Standard ◽

Screen Printed

A commercial and disposable screen-printed carbon electrode (SPCE) has been proposed for a fast, simple and low-cost determination of Ni(II) at very low concentration levels by differential pulse adsorptive stripping voltammetry (DPAdSV) in the presence of dimethylglyoxime (DMG) as complexing agent. In contrast with previously proposed methods, the Ni(II)-DMG complex adsorbs directly on the screen-printed carbon surface, with no need of mercury, bismuth or antimony coatings. Well-defined stripping peaks and a linear dependence of the peak area on the concentration of Ni(II) was achieved in the range from 1.7 to 150 µg L−1, with a limit of detection of 0.5 µg L−1 using a deposition time of 120 s. An excellent reproducibility and repeatability with 0.3% (n = 3) and 1.5% (n = 15) relative standard deviation, respectively, were obtained. In addition, the suitability of the SPCE as sensing unit has been successfully assessed in a wastewater certificated reference material with remarkable trueness and very good reproducibility.

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Application of chemometrics for modeling and optimization of ultrasound-assisted dispersive liquid–liquid microextraction for the simultaneous determination of dyes

npj Clean Water ◽

10.1038/s41545-021-00113-6 ◽

2021 ◽

Vol 4 (1) ◽

Author(s):

Siroos Shojaei ◽

Saeed Shojaei ◽

Arezoo Nouri ◽

Leila Baharinikoo

Keyword(s):

Water Samples ◽

Dynamic Range ◽

Limit Of Detection ◽

World Population ◽

Simple Method ◽

Relative Standard ◽

Ultrasound Assisted ◽

Dispersive Liquid Liquid Microextraction ◽

Liquid Microextraction

AbstractAs the world population continues to grow, so does the pollution of water resources. It is, therefore, important to identify ways of reducing pollution as part of our effort to significantly increase the supply of clean and safer water. In this study, the efficiency of ultrasound-assisted dispersive liquid–liquid microextraction (UA-DLLME) as a fast, economical, and simple method for extraction malachite green (MG) and rhodamine B (RB) dyes from water samples is investigated. In optimal conditions, the linear dynamic range (LDR) for RB and MG is 7.5–1500 ng mL−1 and 12–1000 ng mL−1, respectively. The limit of detection (LOD) is 1.45 ng mL−1 and 2.73 ng mL−1, and limit of quantification (LOQ) is 4.83 ng mL−1 and 9.10 ng mL−1 for RB and MG, respectively. Extraction efficiency is obtained in the range of 95.53–99.60%. The relative standard deviations (RSD) in real water and wastewater samples are less than 3.5. The developed method is used successfully in the determination of RB and MG dyes from water samples and there are satisfactory results.

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Paper-based aptamer-antibody biosensor for gluten detection in a deep eutectic solvent (DES)

Analytical and Bioanalytical Chemistry ◽

10.1007/s00216-021-03653-5 ◽

2021 ◽

Author(s):

Rossella Svigelj ◽

Nicolò Dossi ◽

Cristian Grazioli ◽

Rosanna Toniolo

Keyword(s):

Dynamic Range ◽

Limit Of Detection ◽

Low Cost ◽

Deep Eutectic Solvent ◽

Electrochemical Sensing ◽

Sensing Platform ◽

Screen Printed Carbon Electrode ◽

Highly Sensitive ◽

Rapid Tests

AbstractPaper has been widely employed as cheap material for the development of a great number of sensors such as pregnancy tests, strips to measure blood sugar, and COVID-19 rapid tests. The need for new low-cost analytical devices is growing, and consequently the use of these platforms will be extended to different assays, both for the final consumer and within laboratories. This work describes a paper-based electrochemical sensing platform that uses a paper disc conveniently modified with recognition molecules and a screen-printed carbon electrode (SPCE) to achieve the detection of gluten in a deep eutectic solvent (DES). This is the first method coupling a paper biosensor based on aptamers and antibodies with the DES ethaline. Ethaline proved to be an excellent extraction medium allowing the determination of very low gluten concentrations. The biosensor is appropriate for the determination of gluten with a limit of detection (LOD) of 0.2 mg L−1 of sample; it can detect gluten extracted in DES with a dynamic range between 0.2 and 20 mg L−1 and an intra-assay coefficient of 10.69%. This approach can be of great interest for highly gluten-sensitive people, who suffer from ingestion of gluten quantities well below the legal limit, which is 20 parts per million in foods labeled gluten-free and for which highly sensitive devices are essential. Graphical abstract

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A Low Cost and Simple Lab-on-a-Chip for Spectrophotometric Determination of Ethanol

Walailak Journal of Science and Technology (WJST) ◽

10.48048/wjst.2018.4091 ◽

2017 ◽

Vol 15 (7) ◽

pp. 529-539

Author(s):

Thanyaluck SOMSAENG ◽

Kem PUMSA-ARD ◽

Piyada JITTANGPRASERT

Keyword(s):

Limit Of Detection ◽

Rapid Determination ◽

Low Cost ◽

Colorimetric Detection ◽

Lab On A Chip ◽

Ceric Ammonium Nitrate ◽

Alcoholic Beverages ◽

Manufacturing Cost ◽

Relative Standard

A simple lab-on-a-chip system was developed for the rapid determination of ethanol in different sample matrices, including gasohol and various alcoholic beverages. The colorimetric detection of ethanol using a spectrophotometer was based on the reaction between ethanol with 0.12 M ceric ammonium nitrate in acidic medium to produce a red colored product which gave a maximum absorption at 470 nm. A non-lithographic method was used for creating lab-on-a-chip molds to reduce manufacturing cost and preparation steps. The lab-on-a-chip device was fabricated from polydimethylsiloxane which consisted of a simple Y-shaped working channel. Under optimum conditions, a linear calibration graph was obtained in the concentration range of 0.20 - 20 % (v/v) (r2> 0.999). The limit of detection (3 SD) and limit of quantification (10 SD) were 0.039 and 0.13 % (v/v), respectively. The precision reported in terms of relative standard deviation (RSD) values was less than 1.40 % (n = 15). To demonstrate the lab-on-a-chip’s performance, the determination of ethanol in gasohol and various alcoholic beverages was applied. The results obtained from the developed method compared with a standard gas chromatographic method were well correlated using the paired t-test and linear regression test. The results indicate that the proposed method has shown potential to extend the use of this simple lab-on-a-chip analytical device, due to its simplicity, low cost, lower reagent and sample consumption and high analytical performance. Moreover, the method of fabrication would be an additive manufacturing technique featuring a low equipment cost with no need for clean rooms.

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FIRST-ORDER ULTRAVIOLET DERIVATIVE SPECTROPHOTOMETRIC METHODS FOR DETERMINATION OF RESERPINE IN ANTIHYPERTENSION TABLET

Indonesian Journal of Chemistry ◽

10.22146/ijc.21341 ◽

2012 ◽

Vol 12 (3) ◽

pp. 268-272 ◽

Cited By ~ 1

Author(s):

Latifah K Darusman ◽

Mohamad Rafi ◽

Wulan Tri Wahyuni ◽

Rizna Azrianiningsari

Keyword(s):

Limit Of Detection ◽

Low Cost ◽

Reference Method ◽

Ml Estimation ◽

Mean Values ◽

First Order ◽

Spectrophotometric Methods ◽

Relative Standard ◽

Limit Of Quantitation

A new ultraviolet derivative spectrophotometry (UVDS) method has been developed for determination of reserpine in antihypertension tablets. A first-order UVDS based on the measurement of the distance between peaks to baseline (DZ) at the wavelength of 312 nm was used. Evaluation of analytical performance showed that accuracy as percentage recovery was 99.18-101.13%, precision expressed as relative standard deviation (RSD) was 1.91% and linear correlation was also obtained 0.9998 in the range of 10-50 µg/mL. Estimation of limit of detection and limit of quantitation was 0.8868 µg/mL and 2.6874 µg/mL, respectively. As a reference method, HPLC methods from United States Pharmacopiea (USP) were used. Commercially tablets available were analyzed by the two methods. The content of reserpine in tablets was found 0.2260±0.0033 mg by UVDS and 0.2301±0.0051 mg by the USP methods. The result obtained from the two methods was compared statistically using F-test and t-test and showed no significant differences between the variance and mean values of the two methods at 95% confidence level. This method was faster, easier, low cost and gave result as well as the reference method published by USP.

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Graphene Modified Molecular Imprinting Electrochemical Sensor for Determining the Content of Dopamine

Current Analytical Chemistry ◽

10.2174/1573411014666180730112304 ◽

2019 ◽

Vol 15 (6) ◽

pp. 628-634

Author(s):

Rong Liu ◽

Jie Li ◽

Tongsheng Zhong ◽

Liping Long

Keyword(s):

Electrochemical Sensor ◽

Molecular Imprinting ◽

Neurological Disorders ◽

Room Temperature ◽

Low Cost ◽

Differential Pulse ◽

Current Response ◽

Specific Selectivity ◽

Pulse Voltammetry

Background: The unnatural levels of dopamine (DA) result in serious neurological disorders such as Parkinson’s disease. Electrochemical methods which have the obvious advantages of simple operation and low-cost instrumentation were widely used for determination of DA. In order to improve the measurement performance of the electrochemical sensor, molecular imprinting technique and graphene have always been employed to increase the selectivity and sensitivity. Methods: An electrochemical sensor which has specific selectivity to (DA) was proposed based on the combination of a molecular imprinting polymer (MIP) with a graphene (GR) modified gold electrode. The performance and effect of MIP film were investigated by differential pulse voltammetry (DPV) and cyclic voltammetry (CV) in the solution of 5.0 ×10-3 mol/L K3[Fe(CN)6] and K4[Fe(CN)6] with 0.2 mol/L KCl at room temperature. Results: This fabricated sensor has well repeatability and stability, and was used to determine the dopamine of urine. Under the optimized experiment conditions, the current response of the imprinted sensor was linear to the concentration of dopamine in the range of 1.0×10-7 ~ 1.0×10-5 mol/L, the linear equation was I (µA) = 7.9824+2.7210lgc (mol/L) with the detection limit of 3.3×10-8 mol/L. Conclusion: In this work, a highly efficient sensor for determination of DA was prepared with good sensitivity by GR and great selectivity of high special recognization ability by molecular imprinting membrane. This proposed sensor was used to determine the dopamine in human urine successfully.

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