Gold is known as a highly valuable element in the world’s economy and industrialization, as it is highly exploited in catalysis for material production and as a commodity in manufacturing of accessories, jewelry, and coins. Gold is an abundant element that is naturally occurred in many forms . One of its forms is the existence in nano-dimension, as it is reported to be applicable in the delivery of drug agents , , , , , a common and essential ingredient in cosmetics , in catalysis for industrial production , , , , as a biomarker , , , ,  and as a material for connecting elements in electronic chips , , . The numerous applications of gold have led to the aggregation of dangerous wastes such as gold-mining post-production wastes and electronic wastes , that containing leftover gold, resulting in water pollution to be harmful for the living organisms
Gold ions are known to be very reactive and potentially noxious for human being, whereas, it can chemically interact with human biopolymers, especially proteins and deoxyribonucleic acid (DNA), that could deteriorate kidneys, peripheral nervous system, and liver , . Therefore, it is importantly demanded to investigate techniques for detection of gold ions in the environmental and biological systems. Mostly, the detection of gold ions is performed via different traditional methods, that involving complex steps and the application of large and expensive instrumental tools. Some methods are based on the chromatography, and others that exhibit low quantitative accuracy, including inductive coupled plasma atomic emission spectrometric method (ICP-AES) , atomic absorption spectrometric method (AAS) , , , and the electrochemical analysis , . In contrast, fluorescence spectrometric technique could be ascribed as a better sensing procedure for gold ions, to be advantageous with low in cost, high sensitivity and selectivity .
Numerous reports demonstrated systematic studies for the exploitation of florescent sensors in detection of different pollutants in aquatic streams , , . One the other hand, polymer-based devices could be desirably processed , , , . Polymer-based sensing devices have considerably attracted the interest of researchers, that is evident from the number of recently represented researching articles in literature . Sensing devices derived the information about the environments where they are exploited (locally/remotely). Polymer-based devices could be tuned via an appropriate synthetic method or modification technique, reflecting in the polymers to be prominent as sensors  with diverse applications . As the most considerable issue is the investigation of costless sensing reagents via the exploitation of an ecofriendly approach. One of the most promising techniques for sensors and biosensors fabrication are polymer-derived techniques. The common polymeric matrices applied in sensing objects are composites, nanocomposites hydrogels, molecular imprinting polymers, and conducting polymers , , , . The chemical composition of such polymeric matrices be exploited as sensors could improve the recognition of the target molecules as a basic support for impregnation of different functionalization (dyes metal, nanofillers...etc.,) and by changing the chemical/physical characters, hence promoting a target analyte estimation , . Another advantage for exploitation of polymer-based sensing templates is the opportunities for the modification of their chemical properties in such a pathway that their reactivity, resistance for degradation, flexibility and biodegradability are changed .
Carbon dots (CDs) are one of the most significant family of carbon nanostructures owing to its excellent optical activity, photostability, low toxicity, biocompatibility and high affinity for surface decoration. Whereas, numerous reports in literature were recently considered with investigation of quite simple methods for synthesis of CDs to employ in different applications , , , , . On the other hand, polymer dots (PDs) is a type of zero-dimensional nanostructures with a mean size less than ten nanometer . Investigation of PDs has considerably interested with the researchers attributing to their unique properties such as excellent photoluminescence , biocompatibility with low toxicity . Owing to their unique characters, they were widely applied in drug delivery & antimicrobial/anticancer , , bioimaging , electrocatalysis , photocatalysis , photovoltaic , sensing ,  and energy storage / conversion . In particular, well-known process in photoluminescence like energy transfer, fluorescence quenching, and the sensation of fluorescent spectra for molecular precursor, all points to the wide-scaled applicability of PDs in chemical sensing and biosensing .
There are two functional fractions for the sensor device, a recognition fraction for binding to a target analyte and a transducing fraction for signaling the reaction . The current study demonstrates a quite easy, ecofriendly and cost-effective method for synthesis of florescent PDs from acrylate wastes without any of toxic chemicals. The synthesized PDs were successively immobilized within cationized cotton fabrics that acted as a supporting scaffold to prepare [emailprotected] as a promising florescent dipstick to be easy applicable for efficient, sensitive, rapid and selective florescent detection of gold ions with accurate and satisfactory results. Herein, an investigative methodology is demonstrated for exploitation of acrylate wastes in clustering of florescent PDs to be sequentially exploited as optical sensors for detection of gold ions. The currently reported methodology can be described as a simple and environmentally benign technique for reusing of acrylate wastes to prepare fluorescent PDs. According to our knowledge, no researching reports in literature were concerned with affirming the affinity of PDs ingrained from acrylate wastes to be exploitable as optical sensors for detection of gold ions. In addition to, nucleation of PDs is successively performed without using any of toxic solvents, to be suitable for application in sensitive detection potency. Clustering of PDs via the exploitation of acrylate wastes was approved via different instrumental characterizations like, UV-Visible spectroscopy, Transmission Electron Microscopy, FTIR, 1HNMR and 13CNMR. Moreover, PDs were successively immobilized within cationized cotton to prepare [emailprotected] to prepare easily applicable quenching florescence scaffold for detection of gold ions in aquatic streams. The as-prepared [emailprotected] was well characterized via SEM, EDX & FTIR, whereas, its affinity to be applicable as quenching florescence scaffold was approved via systematic study.
Acrylate wastes were collected from FPC – Coated Technical Textiles in Jeddah – Saudi Arabia. N, N-dimethyl formamide (DMF, 99.8%), Sodium hydroxide (NaOH, 99%), 3-Chloro-2-hydroxypropyl trimethyl ammonium chloride (69%, commercial name CR-2000 and known as Quatt-188) were supplied from Sigma-Aldrich, Germany and applied as received. Bleached cotton fabrics were purified by washing at 100 °C for half hour by using Na2CO3 (2 g/L) in presence of non-ionic surfactant (1 g/L). Fabrics were rinsed
Clustering of PDs by infrared
Acrylate wastes (2 g) were cut into small species and immersed in DMF (100 mL) and the mixture was left to 12 h under magnetic stirring for complete dispersion. The reaction pf mixture was raised to 100 °C for 30 minutes and cooled down. Then the mixture was transferred to autoclave vessel and connected to the infrared machine at 125 ℃ “Infra-Red Dyeing Machine” for five hours. After cooling, the samples were centrifuged (Hermile Z326 K) for 20 minutes at 4000 rpm for the separation of
Cotton fabrics were functionalized by cationization process via the interaction with 3-chloro-2-hydroxypropyl trimethyl ammonium chloride as quaternary ammonium salt as reported in literature . Fabrics were firstly activated by alkalization, though impregnation of fabric (5 gm) in 250 mL of NaOH (1 M) for 20 minutes. Consequently, fabrics were removed and squeezed to remove the excess of NaOH. Secondly, the wet alkalized fabrics were submerged in 250 mL 3-chloro-2-hydroxypropyl trimethyl
Analysis and characterization
Topography and size average of the nucleated PDs were determined from samples micrographs obtained from “JEOL-JEM-1200 TEM (High Resolution Transmission Electron Microscopy, Japan)”. Size distribution of PDs was determined with “4-pi analysis software”. Particle size and “zeta potential” were both measured for the synthesized PDs by using Malvern “Zetasizer Nano ZS, Malvern Instruments Ltd – from UK”. The detection was performed within isolated chamber at room temperature using “dynamic light
Detection of gold ions
The synthesized [emailprotected] were employed in monitoring of metal ions due to their luminescent sensitivity. Different metal ions were selected in the present study represented in PbCl2, HgCl2, AuCl3, TiCl4, Cu(NO3)2, Zn(NO3)2 and Cd(NO3)2. The metal salts were used with 25 mM and the detection was performed at room temperature. Strips from [emailprotected] were dipped in a certain metal salt for 2 minutes, then air dried and the fluorescence emission was measured by using spectro-fluorometer (JASCO
Preparation of PDs
Acrylate wastes were currently exploited for clustering of PDs via infrared assisted technique. With magnetic stirring, acrylate wastes macromolecular chains were formerly hydrolyzed to low molecular weighted fragments. Consequently, clustering of PDs was performed via re-polymerization, aromatization and oxidation under the effect of infra-red irradiation . Dialysis was performed for obtaining ultra-purified PDs to obtain highly-dispersed PDs with regulated topographical characters. The
In the current approach, the clustered PDs were immobilized within cationized cotton in order to prepare [emailprotected] scaffold to be sequentially applicable as optical sensors for detection of gold in aqueous medium. Whereas, cationization of cotton was previously reported in literature to increase the affinity of fabric for successive immobilization of PDs .
FTIR spectral data were plotted in Figure 5 for cationized cotton before and after successive immobilization of PDs, in order to show
[emailprotected] for gold detection
The practical application of the presented work is to perform easy, quite simple and precious/accurate detection of gold ions in aqueous media, as the numerous applications of gold have led to its aggregation as dangerous wastes such as gold-mining post-production wastes and electronic wastes, that containing leftover gold, resulting in water pollution to be harmful for living organisms. As gold is very reactive and potentially noxious for human being, as it can chemically interact with human
The current study demonstrates easy, ecofriendly and cost saving method for clustering of florescent PDs from acrylate wastes without any of toxic chemicals. The synthesized PDs were successively immobilized within cationized cotton fabrics that acted as a supporting scaffold to prepare [emailprotected] as a promising florescent dipstick to be easy applicable for effective, sensible, quick and selective florescent estimation of gold ions to be furtherly commercialized with accurate and satisfactory
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
© 2023 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.
How do fluorescence sensors work? ›
Chopped light of a source with given wavelength is transmitted via a fiber to a fluorescent sensor, placed at the end of the fiber. The sensor is excited to fluorescence at a wavelength different from the exciting source. Fluorescent and exciting radiations are submitted to monochromatic filtering for separation.What is the distance of fluorescence quenching? ›
Fluorescence quenching efficiency is 99.8% at distances of 1–2 nm, and remains near 99% within 5 nm. At longer distances, a decrease in fluorescence quenching occurs and reaches 40% at 40 nm.What is the inner filter effect? ›
An inner-filter effect occurs when the total absorbance of the solution is high (greater than 0.1 au). This leads to a reduction in the intensity of the excitation radiation over the path length.What is the basic principle of fluorescence measurement technique? ›
The basis for fluorescence, the Stokes shift
Fluorescence is based on the property of some molecules that when they are hit by a photon, they can absorb the energy of that photon to get into an excited state. Upon relaxation from that excited state, the same molecule releases a photon: fluorescence emission.
Overview. The fluorescent eye test is useful in determining if there is a scratch or other problem with the surface of the cornea. It can also be used to detect foreign bodies on the surface of the eye, and determine if there is an injury to the eye or eye infection.What does quenching do to metal? ›
In metallurgy, quenching is most commonly used to harden steel by inducing a martensite transformation, where the steel must be rapidly cooled through its eutectoid point, the temperature at which austenite becomes unstable.What temperature is quenching? ›
During quenching at 950˚C - 1100˚C, with the increase of heating temperature, the austenite grain and martensite strip bundles were significantly coarsely coarser, so the hardness and strength of the steel decreased with the increase of heating temperature.What are the two types of fluorescence quenching? ›
The main different types of fluorescence quenching are vibrational relaxation, internal conversion, intersystem crossing (ISC), Förster resonance energy transfer (FERT), Dexter electron transfer, and radiative energy transfer.What is self quenching fluorescence? ›
Abstract. The quantum yield of a fluorophore is reduced when two or more identical fluorophores are in close proximity to each other. The study of protein folding or particle aggregation is can be done based on this above-mentioned phenomenon—called self-quenching.What is the filter effect in fluorescence? ›
The inner filter effect is a common problem in fluorescence spectroscopy, affecting spectral measurements in particular. In highly concentrated solutions the excitation beam is attenuated by the sample so that only the surface facing the excitation beam fluoresces strongly.
What is the inner filter effect of fluorescence? ›
The inner filter effect (IFE) hinders fluorescence measurements, limiting linear dependence of fluorescence signals to low sample concentrations. Modern microplate readers allow movement of the optical element in the vertical axis, changing the relative position of the focus and thus the sample geometry.What are the factors affecting fluorescence? ›
The main factors affecting fluorescence include: conjugated double bonds, effects of substituents and effects of pH. In molecules with more conjugated double bonds absorb a higher quantity of light and therefore cause more intense luminescence. Substituents also have an effect on fluorescence.What are the four essential elements of fluorescence detection systems instruments include? ›
Four essential elements of fluorescence detection systems can be identified from the preceding discussion: 1) an excitation light source (Figure 5), 2) a fluorophore, 3) wavelength filters to isolate emission photons from excitation photons (Figure 5), 4) a detector that registers emission photons and produces a ...What is fluorescence spectroscopy for dummies? ›
Fluorescence spectroscopy uses a beam of light that excites the electrons in molecules of certain compounds, and causes them to emit light. That light is directed towards a filter and onto a detector for measurement and identification of the molecule or changes in the molecule.What are fluorescent polymer materials for detection of? ›
Therefore, fluorescent polymers have been widely studied and applied in fluorescence detection of explosives.Which substances show fluorescence? ›
Examples of Fluorescence
Diamond, rubies, emeralds, calcite, amber, etc. show the same phenomenon when UV rays or X-rays fall on them. One of the best fluorescence examples in nature is bioluminescence.
Fluorescence is measurable by fluorometers. A fluorometer is an instrument designed to measure the various parameters of fluorescence, including its intensity and wavelength distribution of the emission after excitation. Chemists use this to identify properties and the amount of specific molecules in a sample.Why is polymer quenching used? ›
Polymer quenching provides a hardening heat treatment for steel forgings. Polymer quenching can be utilized with excellent results on plain carbon and alloy steels that require superior depth of hardness and uniform, repeatable mechanical properties.What is the best liquid to quench metal with? ›
MINERAL AND TRANSMISSION OILS
Mineral oil quenchants are excellent for oil-hardened steels and steels that require a fast quench rate. They tend to be on the expensive side, but they're highly efficient and have greater cooling capacities for steel alloys.
Traditionally, water, animal fats and fish oils have been used for quenching. Modern methods now include mineral oils (neat), polymers and natural/synthetic esters.
What are the three types of quenching? ›
Certain heat-treatment processes such as hardening and quenching tend to increase the internal stress state of a material. Improper heating to austenitizing temperature can result in thermally induced stress, which may cause a flaw to open up into a crack.How long do you quench metal? ›
Veteran knife makers will tell you to use dedicated heat treat quench oil to get better results. Most agree that the steel really needs to be cooled off at a high rate, like 1 to 2 seconds and, that is absolutely true.What are the four most common methods of quenching metals? ›
Heated materials are often cooled in oil, but can also be quenched using air, water, and brine, depending on the material and desired qualities. As with other heat treating processes, the metal is heated to a point below the melting point where the crystalline structure is fluid.Which quenching method is the most commonly used? ›
10.1 Immersion Cooling (Direct Quenching)
This is the most commonly used method in the quenching of quench- hardenable steels. It is also used for rapid cooling of metals that have been solution treated at elevated temperature.
Different quenching media have different degrees of severity. Caustics are the most severe quenchants, followed by oils, then salts and, finally, gases. The makeup of metal parts and the specified hardness to be achieved dictate which medium is used.What is an example of quenching? ›
1. The process of extinguishing, removing, or diminishing a physical property such as heat or light; e.g., the cooling of a hot metal rapidly by plunging it into water or oil.What makes a good fluorescence quencher? ›
Fluorescence can be quenched if the excited state can be intercepted. An example is as follows. You have a system with your fluorophore and another molecule. Your fluorophore has a smaller HOMO-LUMO gap than this other molecule, so the fluorophore selectively absorbs photons of a certain frequency range and is excited.What is an example of fluorescence quencher? ›
Molecular oxygen, iodide ions and acrylamide are common chemical quenchers. The chloride ion is a well known quencher for quinine fluorescence. Quenching poses a problem for non-instant spectroscopic methods, such as laser-induced fluorescence.What are the colors of fluorescence filters? ›
Common barrier filter colors are blue or pale yellow in the U-block, green or deep yellow in the B-block, and orange or red in the G-block.
How do I choose a fluorescence filter? ›
For optimal fluorescence detection when using a single dye, the excitation and emission filters should be centered on the dye's absorption and emission peaks. To maximize the signal, one can choose excitation and emission filters with wide bandwidths.What is quenching and various factors affecting fluorescence? ›
Increase in temperature are increase fluorescence and decrease in temperature decrease fluorescence. Quenching is the decrease in fluorescence intensity due to specific effect of constituents of the solution itself. It is refer's to any process which decrease the fluorescence intensity of a given substance.Why is fluorescence more selective? ›
The reason why fluorescence is more sensitive than UV-Vis absorption is that they are measured in different ways. Absorbance is measured as the difference in intensity between light passing through the reference and the sample, whereas fluorescence is measured directly without any reference beam.How do you reduce background fluorescence? ›
- Try labeling with a dye that matches a different filter. ...
- Measure the fluorescence intensity from a well that contains only your cells and the drug or treatment. ...
- Check your media. ...
- Check your vessel.
fluorescence, emission of electromagnetic radiation, usually visible light, caused by excitation of atoms in a material, which then reemit almost immediately (within about 10−8 seconds). The initial excitation is usually caused by absorption of energy from incident radiation or particles, such as X-rays or electrons.What is the fluorescent sensor? ›
A fluorescent sensor is the complete optical sensing device:
the light source • the analyte-responsive (supra)molecular moiety properly immobilized • the optical system • the light detector (photomultiplier or photodiode) connected to • appropriate electronics for displaying the signal.
The key difference between UV vis and fluorescence spectroscopy is that UV-visible spectroscopy measures the absorption of light in the UV-visible range, whereas fluorescence spectroscopy measures the light emitted by a sample in the fluorescence range after absorbing light at high energy than the emitted energy level.How does a light sensor detect colors? ›
A color sensor is a type of "photoelectric sensor" which emits light from a transmitter, and then detects the light reflected back from the detection object with a receiver.How do fluorescent probes work PCR? ›
Detection of PCR products in real-time can be accomplished by using fluorescent dyes or probes. Fluorescently-labeled probes detect the amount of specific double-stranded DNA sequences while fluorescent dyes detect only the amount of double-stranded DNA.What are the advantages of fluorescence sensors? ›
Amongst various optical detection techniques, fluorescent sensing is considered highly useful in practical applications for its high sensitivity, specificity, and accuracy compared to other optical sensing techniques.
What controls a fluorescent light? ›
A fluorescent lamp's ballast works to control this. The simplest sort of ballast, generally referred to as a magnetic ballast, works something like an inductor. A basic inductor consists of a coil of wire in a circuit, which may be wound around a piece of metal.What are the two types of fluorescence? ›
A dichroic mirror and emission filter fluorescence.What are the different types of fluorescence detector? ›
There are three types of fluorescent detectors, namely the single wavelength fluorescent detector, multi-wavelength fluorescent detector and laser-induced fluorescent detector.What is the light source of fluorescence detector? ›
A xenon lamp is generally used as a light source for the fluorescence detector.What are the three color sensors? ›
Humans have three kinds of color receptor cells - or “cones” - in their eyes. Each type of cone contains a different visual pigment. These three cone types are called "red", "green" and "blue." Therefore we are “trichromats” (tri = 3, chroma = color). All hues can be produced by mixing red, green and blue light.What three colors is the sensor sensitive to? ›
Both the human eye and digital cameras use sensors that are sensitive to blue, green, and red light, and yet we and the cameras properly sense light of other colors.What color is negative for sensor? ›
Standard color coding for 3 wire Proximity switches is Brown=Positive (+), Black=Load, Blue=Negative (–).What are commonly used fluorescent probes? ›
Commonly used probes are fluorescein derivatives, rhodamine derivatives, polycyclic aromatic hydrocarbons, coumarines, amine reagents such as fluorescamine or NBD-Cl, phycobiliproteins, porphyrins, and metal chelates.Which types of molecule could be used as fluorescent probe? ›
The most commonly labeled molecules are antibodies, which are then used as specific probes for the detection of a particular target.How does fluorescence measure DNA? ›
A homogeneous fluorescence-based DNA detection system has been developed to measure DNA in protein solutions. The technique relies on the increase in fluorescence of a dye molecule when it intercalates into double-stranded (ds) DNA. The increased fluorescence is a direct measurement of the amount of DNA in the sample.