scholarly journals Colorimetric Measurement of Deltamethrin Pesticide Using a Paper Sensor Based on Aggregation of Gold Nanoparticles

Coatings ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 38
Author(s):  
Jingyang Zhu ◽  
Lifeng Yin ◽  
Weiyi Zhang ◽  
Meilian Chen ◽  
Dongsheng Feng ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Color Change ◽  
High Sensitivity ◽  
Cost Effective ◽  
Colorimetric Sensor ◽  
Detection Mechanism ◽  
Colorimetric Measurement ◽  
Fruit Samples ◽  
Pyrethroid Pesticides ◽  
Paper Sensor

Deltamethrin (DEL) is one of the most commonly used pyrethroid pesticides that can cause serious harms to the ecological environment and human health. Herein, we have developed a paper-based colorimetric sensor impregnated with gold nanoparticles (AuNPs) for on-site determination of DEL pesticide. AuNPs show obvious color change on paper device with the presence of DEL. Measuring the gray intensity of the AuNPs on the reaction zone of the paper sensor allows accurate quantitative analysis. The detection mechanism of DEL on paper sensor was confirmed by UV-Vis spectrophotometry (UV-Vis), Fourier transform infrared spectroscopy (FT-IR), and transmission electron microscope (TEM). Under optimal conditions, the colorimetric sensor exhibited high sensitivity, rapid detection, and low detection limit within the values stipulated by Chinese detection standards (LOD = 0.584 mg/L). Besides, detecting DEL in vegetable and fruit samples also gave satisfying results, which were much consistent with those obtained by spectrophotometry. Overall, this work provided a user-friendly, cost-effective and visualized detection platform, which could be applied to rapidly detect DEL pesticides in the food safety field.

Non-enzymatic colorimetric sensor strip based on melamine-functionalized gold nanoparticles assembled on polyamide nanofiber membranes for the detection of metronidazole

2019 ◽  
Vol 11 (29) ◽  
pp. 3706-3713 ◽  
Author(s):  
Mohammed Awad Abedalwafa ◽  
Yan Li ◽  
Chunfang Ni ◽  
Gang Yang ◽  
Lu Wang
Keyword(s):  
Gold Nanoparticles ◽  
Color Change ◽  
High Sensitivity ◽  
Colorimetric Sensor ◽  
Eye Detection ◽  
Naked Eye ◽  
Functionalized Gold Nanoparticles ◽  
Sensitivity And Selectivity ◽  
Nanofiber Membranes ◽  
Naked Eye Detection

Non-enzymatic colorimetric sensor strip for detection of metronidazole (MTZ) was designed and constructed, with high sensitivity and selectivity. Which can be used for naked-eye detection of MTZ with a visible color change from pink to purple.

Simple and Cost Effective Polymer Modified Gold Nanoparticles Based on Colorimetric Determination of L-Cysteine in Food Samples

2021 ◽  
Vol 34 (1) ◽  
pp. 41-57
Author(s):  
Beeta Rani Khalkho ◽  
Anushree Saha ◽  
Bhuneshwari Sahu ◽  
Manas Kanti Deb
Keyword(s):  
Gold Nanoparticles ◽  
High Sensitivity ◽  
Cost Effective ◽  
Food Samples ◽  
Colorimetric Determination ◽  
Plasmon Resonance Band ◽  
Transmission Electron ◽  
Resonance Band ◽  
Absorbance Band

Abstract. The purpose of the present research was to design a method for the colorimetric determination of L-cysteine. We have employed PVA capped gold nanoparticles (GNPs) as a probe. The as-synthesized GNPs were further characterized by UV-vis absorption spectroscopy, transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS) and Zeta potential analyser. The results show that the presence of L-cysteine caused the quenching of the surface plasmon resonance band of the GNPs at 524 nm. It was accompanied by the appearance of a new absorbance of a new absorbance band at 670 nm. The color of the colloidal GNPs changed from wine red to blue. The change in color of the GNPs was due to their aggregation induced by the presence of L-cysteine. Based on these observations, the as-synthesized GNPs were utilized to develop a novel colorimetric sensor for L-cysteine detection in food samples. Significantly, other biomolecules such as alanine, proline, phenylalanine, tryptophane, valine, arginine, glutamic acid, lysine and histidine did not cause any change in the color of the GNPs solutions. This colorimetric probe showed excellent selectivity and high sensitivity for L-cysteine with a detection limit of 2.0 μg mL-1.

Easy-to-Fabricate K2Pd(SO3)2-Dyed Polyester Fabric with Highly Selective and Fast Response to Carbon Monoxide

2021 ◽  
Vol 21 (8) ◽  
pp. 4400-4405
Author(s):  
Junyeop Lee ◽  
Nam Gon Do ◽  
Dong Hyuk Jeong ◽  
Sae-Wan Kim ◽  
Maeum Han ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Color Change ◽  
High Sensitivity ◽  
Cost Effective ◽  
Fast Response ◽  
Polyester Fabric ◽  
High Porosity ◽  
Sensing Material ◽  
Sensitivity And Selectivity ◽  
And Performance

Carbon monoxide (CO) is an odorless, colorless, tasteless, extremely flammable, and highly toxic gas. It is produced when there is insufficient oxygen supply during the combustion of carbon to produce carbon dioxide (CO2). CO is produced from operating engines, stoves, or furnaces. CO poisoning occurs when CO accumulates in the bloodstream and can result in severe tissue damage or even death. Many types of CO sensors have been reported, including electrochemical, semiconductor metal-oxide, catalytic combustion, thermal conductivity, and infrared absorption-type for the detection of CO. However, despite their excellent selectivity and sensitivity, issues such as complexity, power consumption, and calibration limit their applications. In this study, a fabricbased colorimetric CO sensor is proposed to address these issues. Potassium disulfitopalladate (II) (K2Pd(SO3)2) is dyed on a polyester fabric as a sensing material for selective CO detection. The sensing characteristics and performance are investigated using optical instruments such as RGB sensor and spectrometer. The sensor shows immediate color change when exposed to CO at a concentration that is even lower than 20 ppm before 2 min. The fast response time of the sensor is attributed to its high porosity to react with CO. This easy-to-fabricate and cost-effective sensor can detect and prevent the leakage of CO simultaneously with high sensitivity and selectivity toward CO.

scholarly journals Fabrication of Carbon Disulfide Added Colloidal Gold Colorimetric Sensor for the Rapid and On-Site Detection of Biogenic Amines

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1738
Author(s):  
Namhyeok Choi ◽  
Bumjun Park ◽  
Min Ji Lee ◽  
Reddicherla Umapathi ◽  
Seo Yeong Oh ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Biogenic Amines ◽  
Carbon Disulfide ◽  
Colloidal Gold ◽  
Limit Of Detection ◽  
Morphological Changes ◽  
Cost Effective ◽  
Colorimetric Sensor ◽  
Single Time ◽  
Colloidal Gold Nanoparticles

Meat is often wasted due to the perceived concerns of its shelf life and preservation. Specifically, in meat formation, biogenic amines (BAs) are the major agents to spoil them. Herein, we have developed a carbon disulfide (CS2) added colloidal gold nanoparticles-based colorimetric sensor for the rapid and on-site detection of biogenic amines. Transmission electron microscopy is used to observe the morphological changes in colloidal gold nanoparticles and aggregation behavior of CS2 added to the colloidal gold nanoparticles’ solution. Raman spectroscopic analysis is further used to characterize the peaks of CS2, Cad and CS2-Cad molecules. Absorption spectroscopy is used to estimate the colorimetric differences and diffuse reflectance spectra of the samples. The sensing analysis is performed systematically in the presence and absence of CS2. CS2 added colloidal gold nanoparticles colorimetric sensor detected the BAs with a limit of detection (LOD) value of 50.00 µM. Furthermore, the developed sensor has shown an LOD of 50.00 µM for the detection of multiple BAs at a single time. The observed differences in the colorimetric and absorption signals indicate that the structure of BAs is converted to the dithiocarbamate (DTC)-BA molecule, due to the chemical reactions between the amine groups of BAs and CS2. Significantly, the developed colorimetric sensor offers distinct features such as facile fabrication approach, on-site sensing strategy, rapid analysis, visual detection, cost-effective, possibility of mass production, availability to detect multiple BAs at a single time and appreciable sensitivity. The developed sensor can be effectively used as a promising and alternative on-site tool for the estimation of BAs.

scholarly journals Portable on-chip colorimetric biosensing platform integrated with a smartphone for label/PCR-free detection of Cryptosporidium RNA

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
George S. Luka ◽  
Ephraim Nowak ◽  
Quin Robert Toyata ◽  
Nishat Tasnim ◽  
Homayoun Najjaran ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Color Change ◽  
Colorimetric Assay ◽  
Cost Effective ◽  
Naked Eye ◽  
Sensing Platform ◽  
3D Printed ◽  
Protozoan Pathogen ◽  
On Chip ◽  
Colorimetric Biosensing

AbstractCryptosporidium, a protozoan pathogen, is a leading threat to public health and the economy. Herein, we report the development of a portable, colorimetric biosensing platform for the sensitive, selective and label/PCR-free detection of Cryptosporidium RNA using oligonucleotides modified gold nanoparticles (AuNPs). A pair of specific thiolated oligonucleotides, complementary to adjacent sequences on Cryptosporidium RNA, were attached to AuNPs. The need for expensive laboratory-based equipment was eliminated by performing the colorimetric assay on a micro-fabricated chip in a 3D-printed holder assembly. A smartphone camera was used to capture an image of the color change for quantitative analysis. The detection was based on the aggregation of the gold nanoparticles due to the hybridization between the complementary Cryptosporidium RNA and the oligonucleotides immobilized on the AuNPs surface. In the complementary RNA’s presence, a distinctive color change of the AuNPs (from red to blue) was observed by the naked eye. However, in the presence of non-complementary RNA, no color change was observed. The sensing platform showed wide linear responses between 5 and 100 µM with a low detection limit of 5 µM of Cryptosporidium RNA. Additionally, the sensor developed here can provide information about different Cryptosporidium species present in water resources. This cost-effective, easy-to-use, portable and smartphone integrated on-chip colorimetric biosensor has great potential to be used for real-time and portable POC pathogen monitoring and molecular diagnostics.

scholarly journals Ranolazine-Functionalized Copper Nanoparticles as a Colorimetric Sensor for Trace Level Detection of As3+

Nanomaterials ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 83 ◽  
Author(s):  
Gul Laghari ◽  
Ayman Nafady ◽  
Sameerah Al-Saeedi ◽  
Sirajuddin ◽  
Syed Sherazi ◽  
...  
Keyword(s):  
Copper Nanoparticles ◽  
Color Change ◽  
Cost Effective ◽  
Colorimetric Sensor ◽  
Spherical Particles ◽  
Localized Surface Plasmon ◽  
Force Microscopy ◽  
Highly Sensitive ◽  
Dark Green ◽  
Average Size

This study involves environmentally friendly synthesis of copper nanoparticles in aqueous medium without inert gas protection, using ranolazine as a capping material. UV-Visible (UV-Vis) spectrometry showed that ranolazine-derived copper nanoparticles (Rano-Cu NPs) demonstrate a localized surface plasmon resonance (LSPR) band at 573 nm with brick-red color under optimized parameters, including pH, reaction time, and concentrations of copper salt, hydrazine hydrate, and ranolazine. The coating of ranolazine on the surface of Cu NPs was studied via Fourier transform infrared (FTIR) spectroscopy. Scanning electron microscopy (SEM) revealed that Rano-Cu NPs consist of spherical particles. X-ray diffraction (XRD) verified that Rano-Cu NPs are crystalline in nature. Atomic force microscopy (AFM) showed that the average size of Rano-Cu NPs was 40 ± 2 nm in the range of 22–95 nm. Rano-Cu NPs proved to be highly sensitive as a selective colorimetric sensor for As3+ via color change from brick red to dark green, in the linear range of 3.0 × 10−7 to 8.3 × 10−6 M, with an R² value of 0.9979. The developed sensor is simple, cost effective, highly sensitive, and extremely selective for As3+ detection, showing a low detection limit (LDL) of 1.6 × 10−8 M. The developed sensor was effectively tested for detection of As3+ in some water samples.

scholarly journals Hydrogen-Bonding Recognition-Induced Colorimetric Determination of Hydrazine Based on the Tryptophan Capped Gold Nanoparticles

2013 ◽  
Vol 2013 ◽  
pp. 1-7
Author(s):  
Wenhua Gao ◽  
Jing Xi ◽  
Yunsheng Chen ◽  
Song Xiao ◽  
Xingqing Wang ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Color Change ◽  
Detection System ◽  
Colorimetric Method ◽  
Cost Effective ◽  
Colorimetric Determination ◽  
Chloroauric Acid ◽  
Sample Analysis ◽  
Higher Temperature

A simple, cost-effective, and rapid colorimetric method for hydrazine detection using tryptophan-caped gold nanoparticles (Trp-AuNPs) has been developed. Tryptophan (Trp) is a protein with reducibility and amino group which can reduce chloroauric acid (HAuCl4) to AuNPs and modify the surface of AuNPs simultaneously. The Trp-AuNPs could be used to quantitatively detect hydrazine and showed different responses to vary concentration of hydrazine in an aqueous solution based on the aggregation-induced color change of Trp-AuNPs. The real water sample analysis verified the conclusion. The sensitivity of the detection system was influenced by the size of AuNPs which is determined by the pH of the detection system, the concentration of Trp, and the react time. We found that higher temperature contributed to more rapidly results. The detection system can detect as low as 1 μM hydrazine. We expect our approach to have wide-ranging applications in the developing region for monitoring water quality in some areas.

scholarly journals Paper-Based Vapor Detection of Formaldehyde: Colorimetric Sensing with High Sensitivity

Chemosensors ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 335
Author(s):  
Chenglong Liao ◽  
Miao Zhang ◽  
Nan Gao ◽  
Qingyun Tian ◽  
Jiangfan Shi ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Air Quality ◽  
Color Change ◽  
Limit Of Detection ◽  
High Sensitivity ◽  
Colorimetric Sensor ◽  
Thymol Blue ◽  
Vapor Concentration ◽  
Ph Indicators ◽  
Quality Threshold

We report on a novel colorimetric sensor system for highly sensitive detection of formaldehyde (FA) in the gas phase. The sensor is constructed with paper towel as a substrate coated with the sulfuric acid salt of hydroxylamine ((NH2OH)2·H2SO4) together with two pH indicators, bromophenol blue and thymol blue. Upon exposure to FA, the hydroxylamine will react with the absorbed FA to form a Schiff base (H2C=N-OH), thus releasing a stoichiometric amount of sulfuric acid, which in turn induces a color change of the pH indicator. Such a color change was significantly enriched by incorporating two pH indicators in the system. With the optimized molar ratio of the two pH indicators, the color change (from brown to yellow, and to red) could become so dramatic as to be visible to the eye depending on the concentration of FA. In particular, under 80 ppb of FA (the air quality threshold set by WHO) the color of the sensor substrate changes from brown to yellow, which can even be envisioned clearly by the naked eyes. By using a color reader, the observed color change can be measured quantitatively as a function of the vapor concentration of FA, which produces a linear relationship as fitted with the data points. This helps estimate the limit of detection (LOD), to be 10 ppb under an exposure time of 10 min, which is much lower than the air quality threshold set by WHO. The reported sensor also demonstrates high selectivity towards FA with no color change observed when exposed to other common chemicals, including solvents and volatile organic compounds. With its high sensitivity and selectivity, the proposed paper-based colorimetric sensor thus developed can potentially be employed as a low-cost and disposable detection kit that may find broad application in detecting FA in indoor air and many other environments.

scholarly journals Cost-Effective Foam-Based Colorimetric Sensor for Roadside Testing of Alcohol in Undiluted Saliva

Chemosensors ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 334
Author(s):  
Krittapas Kaewnu ◽  
Kiattisak Promsuwan ◽  
Apichai Phonchai ◽  
Adul Thiangchanya ◽  
Dongsayam Somapa ◽  
...  
Keyword(s):  
Color Change ◽  
Limit Of Detection ◽  
Potassium Dichromate ◽  
Cost Effective ◽  
Colorimetric Sensor ◽  
Alcohol Concentration ◽  
Blood Alcohol ◽  
Spectrophotometric Detection ◽  
Significant Difference ◽  
Alcohol Sensor

A novel foam-based colorimetric alcohol sensor was developed for the detection of alcohol in saliva. Detection was based on the color change of a potassium dichromate-sulfuric acid solution absorbed by melamine foam. In the presence of alcohol, the orange colorimetric sensor changed color to brown, green and, ultimately, blue, depending on the concentration of alcohol in the sample. The response of the proposed sensor toward alcohol was linear from 0.10 to 2.5% v/v. The limit of detection was 0.03% v/v. Alcohol concentration could be determined using the naked eye in the range of 0.00 to 10% v/v. The developed alcohol sensor presented good operational accuracy (RSD = 0.30–1.90%, n = 8) and good stability for 21 days when stored at 25 °C and 75 days when stored at 4 °C. The results of alcohol detection with the developed sensor showed no significant difference from the results of spectrophotometric detection at a 95% confidence level (p > 0.05). The sensor was easy to use, small, inexpensive and portable, enabling drivers to accurately measure their own blood alcohol level and providing convenient speed in forensic applications.

Preparation of gold nanoparticles using pyridine-formaldehyde as a reducing agent and its application in high sensitivity colorimetric detection of Pb2+

2019 ◽  
Vol 11 (34) ◽  
pp. 4362-4369 ◽  
Author(s):  
Liling Lei ◽  
Haimei Song ◽  
Junhong Zhao ◽  
Qingxiang Yang ◽  
Zhijun Chen
Keyword(s):  
Gold Nanoparticles ◽  
Aqueous Solutions ◽  
Colorimetric Detection ◽  
High Sensitivity ◽  
Colorimetric Sensor ◽  
Reducing Agent ◽  
New Method

A new method for preparing AuNPs has been successfully developed by using pyridine-formaldehyde as reducing agent. The AuNPs were used in colorimetric sensor for detection of Pb2+ in aqueous solutions.

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