Humic Acid Functionalized - Silver Nanoparticles as Nanosensor for Colorimetric Detection of Copper (II) Ions in Aqueous Solutions

2020 ◽  
Vol 831 ◽  
pp. 142-150
Author(s):  
Edgar Clyde R. Lopez ◽  
Michael Angelo Zafra ◽  
Jon Nyner L. Gavan ◽  
Emil David A. Villena ◽  
Francis Eric P. Almaquer ◽  
...  

Humic acid - functionalized silver nanoparticles (HA-AgNPs) were successfully synthesized and used to detect Cu (II) ions in aqueous solutions. The HA-AgNPs was shown to have an average hydrodynamic diameter of 101.4 nm and a polydispersity index of 0.447. The absorbance spectra of HA-AgNPs showed the characteristic local surface plasmon resonance (LSPR) peak of AgNPs at 408.3 nm. Addition of Cu (II) in the HA-AgNPs led to their agglomeration as evidenced by the change in their surface morphology and their corresponding optical absorbance spectra. The synthesized HA-AgNPs showed a strong linear response for Cu (II) concentrations in the range of 0.00 – 1.25 mM with a limit of detection (LoD) of 4.4428 ± 0.1091 mg L-1, a limit of quantification (LoQ) of 14.8094 ± 0.3636 mg L-1, and a limit of blank (LoB) of 0.1214 ± 0.0065 mg L-1. Statistical analysis showed that this calibration curve could be used to quantify Cu (II) concentrations within a 95% confidence level. Furthermore, HA-AgNPs was found to be selective for Cu (II) detection based on the selectivity study against common metal ions found in drinking water. This shows that the synthesized HA-AgNPs can be used as an environment-friendly colorimetric nanosensor for rapid and point-of-need quantification of Cu (II) ions in aqueous media.

2021 ◽  
Author(s):  
SELCAN KARAKUŞ ◽  
Nevin Taşaltın ◽  
Cihat Taşaltın ◽  
Nuray Bekoz Üllen

Abstract Green and low-cost synthesis strategy for ultrasonic preparation of polymer blend matrix based silver nanoparticles (Ag NPs) and the development of rapid and high sensitive detection route have a great attention in biomedical applications. Therefore, in this study, we investigated the hydrogen peroxide detection performance of Konjac gum (KG)/PEG-Ag NPs. The KG/PEG-Ag NPs was synthesized via an ultrasonic process and characterized by different techniques such as ultraviolet–visible spectroscopy (UV–Vis), Fourier-Transform Infrared spectroscopy (FT-IR), Scanning Electron Microscope (SEM) and Energy Dispersive X-ray spectroscopy (EDX). Furthermore, we determined the experimental optimization on the effect of the rheological parameters of nanostructure with the highest correlation constant (R 2 : 0.989-0.996), and the intrinsic viscosity (14.71-26.77 dl/g). To provide the miscible polymer blends and homogeneous dispersion of the nanostructure, we compared the rheological parameters with the experimental results. The response time was less than 5 s and the lower limit of detection was 0.071 μM. This novel highly sensitive, rapid, and naked-eye colorimetric biosensor based Ag NPs which are prepared ultrasonic manufacturing approach, opens up a green approach of development facile and rapid detection of hydrogen peroxide in practical biomedical applications.


2012 ◽  
Vol 166-167 ◽  
pp. 365-371 ◽  
Author(s):  
Aswathy Ravindran ◽  
M. Elavarasi ◽  
T.C. Prathna ◽  
Ashok M. Raichur ◽  
N. Chandrasekaran ◽  
...  

Nanomaterials ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1604 ◽  
Author(s):  
Masood Hussain ◽  
Ayman Nafady ◽  
Sirajuddin ◽  
Ahmet Avcı ◽  
Erol Pehlivan ◽  
...  

We report a novel, simple, efficient, and green protocol for biogenic synthesis of silver nanoparticles (AgNPs) in aqueous solution using clove (Syzygium aromaticum) extract as a reducing and protecting agent. Ultraviolet-visible (UV-Vis) spectroscopy was employed to monitor the localized surface plasmon resonance (LSPR) band of clove extract-derived AgNPs prepared under various conditions. Fourier-transform infrared (FTIR) spectroscopy analysis provided information about the surface interaction of the clove extract with the AgNPs. Ultrahigh-resolution transmission electron microscopy (UHRTEM) results confirmed the formation of spherical, uniformly distributed clove extract-capped AgNPs with sizes in the range of 2–20 nm (average size: 14.4 ± 2 nm). Powder X-ray diffractometry analysis (PXRD) illustrated the formation of pure crystalline AgNPs. These AgNPs were tested as a colorimetric sensor to detect trace amounts of vinclozolin (VIN) by UV-Vis spectroscopy for the first time. The AgNP-based sensor demonstrated very sensitive and selective colorimetric detection of VIN, in the range of 2–16 µM (R2 = 0.997). The developed sensor was green, simple, sensitive, selective, economical, and novel, and could detect trace amounts of VIN with limit of detection (LOD) = 21 nM. Importantly, the sensor was successfully employed for the determination of VIN in real water samples collected from various areas in Turkey.


Molecules ◽  
2021 ◽  
Vol 26 (21) ◽  
pp. 6355
Author(s):  
Francisca T. S. M. Ferreira ◽  
Raquel B. R. Mesquita ◽  
António O. S. S. Rangel

In this work, the design of a microfluidic paper-based analytical device (μPAD) for the quantification of nitrate in urine samples was described. Nitrate monitoring is highly relevant due to its association to some diseases and health conditions. The nitrate determination was achieved by combining the selectivity of the nitrate reductase enzymatic reaction with the colorimetric detection of nitrite by the well-known Griess reagent. For the optimization of the nitrate determination μPAD, several variables associated with the design and construction of the device were studied. Furthermore, the interference of the urine matrix was evaluated, and stability studies were performed, under different conditions. The developed μPAD enabled us to obtain a limit of detection of 0.04 mM, a limit of quantification of 0.14 mM and a dynamic concentration range of 0.14–1.0 mM. The designed μPAD proved to be stable for 24 h when stored at room temperature in air or vacuum atmosphere, and 60 days when stored in vacuum at −20 °C. The accuracy of the nitrate μPAD measurements was confirmed by analyzing four certified samples (prepared in synthetic urine) and performing recovery studies using urine samples.


2021 ◽  
Vol 5 (1) ◽  
pp. 9
Author(s):  
Amer Charbaji ◽  
Hojat Heidari-Bafroui ◽  
Nasim Rahmani ◽  
Constantine Anagnostopoulos ◽  
Mohammad Faghri

Paper-based microfluidic technology is a relatively new field of research that provides low-cost platforms and sensors for point-of-care diagnostics. While the majority of research in this field has been for biomedical applications, more and more paper-based devices and platforms are being designed and developed for environmental applications, such as water quality monitoring and assessment. One such application is the detection of nitrate in water samples. Colorimetric detection of nitrate by paper-based devices using the Griess assay requires the reduction of nitrate to nitrite before undergoing the reaction. In this paper, we measured the performance of a paper-based dip strip for detecting nitrate and nitrite by calculating its limit of detection and limit of quantification. We also calculated the reduction efficiency of vanadium (III) chloride in the dip strip for detecting nitrate. Our results show that the reduction time of nitrate via vanadium (III) chloride is much longer than that when using zinc microparticles. Our results also show that the performance of the dip strip using vanadium (III) chloride for nitrate detection is not as good as more intricate paper-based devices that have a separate reaction zone with zinc microparticles. The limits of detection and quantification calculated were 3.352 and 7.437 ppm, and the nitrate reduction efficiency varied over the range of nitrate concentrations tested.


Sensors ◽  
2021 ◽  
Vol 21 (19) ◽  
pp. 6353
Author(s):  
Saeedeh Babazadeh ◽  
Ramanand Bisauriya ◽  
Marilena Carbone ◽  
Ludovica Roselli ◽  
Daniele Cecchetti ◽  
...  

Water pollution caused by hexavalent chromium (Cr(VI)) ions represents a serious hazard for human health due to the high systemic toxicity and carcinogenic nature of this metal species. The optical sensing of Cr(VI) through specifically engineered nanomaterials has recently emerged as a versatile strategy for the application to easy-to-use and cheap monitoring devices. In this study, a one-pot oxidative method was developed for the cage opening of C60 fullerene and the synthesis of stable suspensions of N-doped carbon dots in water–THF solutions (N-CDs-W-THF). The N-CDs-W-THF selectively showed variations of optical absorbance in the presence of Cr(VI) ions in water through the arising of a distinct absorption band peaking at 550 nm, i.e., in the transparency region of pristine material. Absorbance increased linearly, with the ion concentration in the range 1–100 µM, thus enabling visual and ratiometric determination with a limit of detection (LOD) of 300 nM. Selectivity and possible interference effects were tested over the 11 other most common heavy metal ions. The sensing process occurred without the need for any other reactant or treatment at neutral pH and within 1 min after the addition of chromium ions, both in deionized and in real water samples.


RSC Advances ◽  
2016 ◽  
Vol 6 (42) ◽  
pp. 36171-36179 ◽  
Author(s):  
B. Ajitha ◽  
Y. Ashok Kumar Reddy ◽  
P. Sreedhara Reddy ◽  
Hwan-Jin Jeon ◽  
Chi Won Ahn

Catalytic reaction between PVA-capped AgNPs and hydrogen peroxide, and the corresponding LSPR optical absorbance spectra as a function of time.


Author(s):  
Mohammad Hamzah Hamzah ◽  
Rawa M M Taqi ◽  
Muna M. Hasan ◽  
Raid J. M. Al-Timimi

A simple and accurate spectrophotometric method for the determination of Trifluoperazine HCl in pure and dosage forms was developed. The method is based on the reaction between Trifluoperazine HCl and p-chloroaniline in the presence of cerium ion as oxidizing agent which lead to the formation of violate color product that absorbed at a maximum wavelength 570nm while the blank solution was pink. Under the optimum conditions a linear relationship between the intensity and concentration of TRF in the range 4-50μg/ml was obtained . The molar absorptivity 3.74×103 L.mol-1.cm-1 , Limit of detection (2.21μg/ml), while limit of quantification was 7.39μg/ml. The proposed analytical method was compared with standard method using t-test and F-test , the obtained results shows there is no significant differences between proposed method and standard method. Based on that the proposed method can be used as an alternative method for the determination of TRF in pure and dosage forms.


Author(s):  
Carla Eiras

Interleukin-6 (IL-6) is a multifunctional cytokine and high bloodstream levels of which have been associated with severe inflammatory diseases, such as dengue fever, sepsis, various cancers, and visceral leishmaniasis (VL). Rapid tests for the quantification of IL-6 would be of great assistance for the bedside diagnosis and treatment of diseases such as VL. We have developed a lateral flow assay (LFA) for rapid and colorimetric IL-6 detection, consisting of anti-IL-6 antibodies conjugated to gold nanoparticles (AuNPs). The optimal concentration of anti-IL-6 used in the conjugate was determined to be 800.0 μg/mL, based on an aggregation assay using LFA. A linear relationship between IL-6 standard concentration and color intensity was observed after 20 min, with a linear range between 1.25 ng/mL and 9,000 ng/mL. The limit of detection for this method was estimated a t0.38 ng/mL. The concentration of IL-6 in five patients with severe VL was measured using LFA, and the results were consistent with those obtained using the cytometric bead array (CBA) method. A thorough analysis of the LFA membranes’ surface morphology, before and after sample contact, was performed using atomic force microscopy (AFM).The prototype described here is still being tested and improved, but this LFA will undoubtedly be of great help in the clinical quantification of IL-6.


Sign in / Sign up

Export Citation Format

Share Document