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.

Highly sensitive colorimetric determination of malathion using gold nanoparticles

2016 ◽  
Vol 16 (5) ◽  
pp. 1214-1220 ◽  
Author(s):  
Tayebeh Kohzadi ◽  
Mahmoud Roushani
Keyword(s):  
Gold Nanoparticles ◽  
High Sensitivity ◽  
Colorimetric Determination ◽  
Good Precision ◽  
Buffer Solution ◽  
Microscopy Technique ◽  
Resonance Band ◽  
Highly Sensitive ◽  
Agriculture Products

A highly sensitive method is presented for the colorimetric determination of malathion using gold nanoparticles (AuNPs). In this approach, the synthesized AuNPs solution was stabilized by the citrate anions as their repulsion protected the AuNPs from aggregation. The synthesized AuNPs were characterized morphologically by using transmission electron microscopy technique. Malathion caps the surface of AuNPs and induces the aggregation of AuNPs in Britton–Robinson buffer solution. The reaction was monitored spectrophotometrically by measuring the decrease in the plasmon resonance band of the AuNPs at 527 nm after 9 min. The effect of reaction variables on the reaction sensitivity was investigated and furthermore, the interference of common ions was effectively avoided. The calibration curve is linear over the concentration range 3.3 × 10−7 to 3.3 × 10−6 mol/L of malathion with good precision and accuracy and the detection limit was down to 1.5 × 10−7 mol/L. The developed approach does not use complex and expensive instruments. The high sensitivity of the proposed method allowed its successful application to wheat and water samples. Thus, the proposed strategy can serve as a powerful method for the rapid diagnosis of malathion in agriculture products.

scholarly journals Fabrication of a Food Nano-Platform Sensor for Determination of Vanillin in Food Samples

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 2817 ◽  
Author(s):  
Vinod Gupta ◽  
Hassan Karimi-Maleh ◽  
Shilpi Agarwal ◽  
Fatemeh Karimi ◽  
Majede Bijad ◽  
...  
Keyword(s):  
High Sensitivity ◽  
Food Samples ◽  
Precipitation Method ◽  
Single Wall Carbon Nanotubes ◽  
Modified Carbon Paste Electrode ◽  
Carbon Paste ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Paste Electrode

Herein, we describe the fabrication of NiO decorated single wall carbon nanotubes (NiO-SWCNTs) nanocomposites using the precipitation method. The synthesized NiO-SWCNTs nanocomposites were characterized by X-ray diffraction (XRD) and Transmission electron microscopy (TEM). Remarkably, NiO-SWCNTs and 1-butylpyridinium hexafluorophosphate modified carbon paste electrode (CPE/NiO-SWCNTs/BPrPF6) were employed for the electrochemical detection of vanillin. The vanillin sensor showed an ultra-high sensitivity of 0.3594 μA/μM and a low detection limit of 0.007 μM. In the final step, the NiO-SWCNTs/BPrPF6 was used as the suitable tool for food analysis.

Cocaine detection using aptamer and molybdenum disulfide-gold nanoparticle-based sensors

Nanomedicine ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. 325-335
Author(s):  
Li Gao ◽  
Wenwen Xiang ◽  
Zebin Deng ◽  
Keqing Shi ◽  
Huixing Wang ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Detection Limit ◽  
Molybdenum Disulfide ◽  
Low Cost ◽  
High Sensitivity ◽  
Label Free ◽  
Sensing System ◽  
Plasmon Resonance Band ◽  
Resonance Band ◽  
Cocaine Detection

Aim: The current work highlighted a novel colorimetric sensor based on aptamer and molybdenum disulfide (MoS2)-gold nanoparticles (AuNPs) that was developed for cocaine detection with high sensitivity. Materials & methods: Due to the presence of the plasmon resonance band on the surface of AuNPs, AuNPs aggregated and the color was changed from red to blue after adding a certain concentration of NaCl. We used MoS2 to optimize the sensing system of AuNPs. The folded conformation of the aptamer in combination with cocaine enhanced the salt tolerance of the MoS2-AuNPs, effectively preventing their aggregation. Results & conclusion: The detection limit of cocaine was 7.49 nM with good selectivity. The method based on MoS2-AuNPs colorimetry sensor is simple, quick, label-free and low cost.

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.

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