Colorimetric sensor based on silver nanoparticles for the determination of volatile sulfur compounds

专利摘要:
Solid colorimetric sensor for the detection and/or determination of volatile sulphides in gases or in any matrix in which volatile sulfides exist or are generated. It is based on silver nanoparticles immobilized in a membrane. This sensor allows, in a portable way (in situ) and passively, in only 10 min, a simple detection/determination by visual observation, by means of the rgb coordinates of the digital image and/or by diffuse reflectance. They have adequate selectivity for the monitoring of volatile sulfur compounds and have been found not to interfere with the detection of other volatile compounds such as amines, ethanol or acetone. The sensitivity is good, with a limit of detection and quantification of 45 ppb v/v and 150 ppb v/v respectively obtained through the measurement of color by diffuse reflectance. (Machine-translation by Google Translate, not legally binding)
公开号:ES2643857A1
申请号:ES201600440
申请日:2016-05-24
公开日:2017-11-24
发明作者:Pilar CAMPINS FALCÓ；Carmen MOLINS LEGUA；Yolanda MOLINER MARTÍNEZ；Rosa HERRÁEZ HERNÁNDEZ；Jorge VERDU ANDRÉS；Neus JORNET MARTÍNEZ；Ana Isabel ARGENTE GARCÍA
申请人:Universitat de Valencia；
IPC主号:

专利说明:

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DESCRIPTION
Colorimetric sensor based on silver nanoparticles for the determination of volatile sulfur compounds.
Field of the Invention
The device developed falls within the field of the detection of volatile sulphide compounds (R-S- and S-2) such as hydrogen sulfide (H2S) and methyl mercaptan (CH3SH) in gases, eg air. The type of sampling is passive and detection is quick and simple, by direct observation of the color change. It allows to detect low levels of these compounds, being able to apply for detection in the atmosphere as well as in enclosed spaces and even for the analysis of halitosis in human respiration, among others.
Summary of the invention
In the present invention a solid colorimetric sensor for the determination of volatile sulfide compounds (R-S- and S-2) is described. It is based on the immobilization of silver nanoparticles (hereinafter abbreviated as AgNPs) stabilized with sodium citrate and immobilized on a preferably nylon membrane. This sensor does not need any type of pretreatment for its use, since it is a solid sensor that is used directly at the time of determination; It has sustainable characteristics and is not toxic. In addition, it is a passive type sensor, that is, it does not require any external source of energy, so its energy cost is zero. Likewise, it stands out for its application potential and simplicity, allowing the quantitative and / or semi-quantitative determination of sulfides by simple visual observation, with detection limits of 45 ppb (v / v) and quantification of 150 ppb (v / v) obtained By measuring the color by diffuse reflectance and in 10 minutes of exposure time, although increasing the exposure time to 30 minutes is possible to achieve detection limits of 25 ppb (v / v). It has good stability at room temperature protected by a film, remaining stable for a period of 3 months.
State of the art
Volatile sulfur compounds such as hydrogen sulfide (H2S), characteristic for their smell of rotten eggs, are toxic and harmful gases for the environment. They are formed mainly by the decomposition of organic matter and are usually found in nature in volcanic gases, natural gas, oil crude, stagnant waters, etc. However, the greater amounts of hydrogen sulfide and other volatile sulfur compounds are generated as a result of industrial activities such as the processing and refining of oil / natural gas, wastewater treatment plants, landfills, etc. According to Royal Decree 678/2014 that sets the objectives for the improvement of air quality, the average concentration in thirty minutes of hydrogen sulfide should not exceed 100 pg / m3 (83 ppb v / v).
Other relevant volatile sulfide compounds are methylmercaptan (CH3SH) and dimethylmercaptan ((CH3) 2S). These compounds, together with hydrogen sulfide, are responsible for bad breath and / or halitosis. Halitosis is a common problem that affects 25% of people, and it is believed that 50% of people will suffer at some point in their life. For people who suffer from it, this problem can be an obstacle in their normal functioning and interaction with society. Currently, halitosis is still a taboo subject and the investigation in this regard is very limited.
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According to several of the studies analyzed (Analytics Chimica Acta 2010, 661, 97; International Oral Science 2012, 4, 55; Sensors and Actuators 2009, 136, 73; Med. Princ. Pract. 2011, 20, 75) it can be concluded that concentrations below 100-200 ppb (v / v) will be within the normal range, while values equal to or greater than 300-400 ppb (v / v) will produce a persistent and diagnosable oral odor such as severe halitosis.
A compilation of different types of methods to monitor hydrogen sulfide can be found in Trends in Analytical Chemistry, 2012, 32, 87-99. Different types of sensors are described in this compilation, from those consisting of semiconductor metal oxides to those based on surface acoustic waves.
The most commonly used methods for the detection of volatile sulfur compounds are gas chromatographic methods (Health Science 2014, 2, 80). They are sensitive and precise methods; however, they have a high economic cost, and are not portable. These methods require relatively long analysis times, with multiple stages of conditioning and sample preparation that can only be performed by experienced personnel. Although they can be used for the detection of halitosis, however specialists such as dentists and doctors use the halitometer, an instrument of lower cost, portable and easier to use. But this instrument remains inaccessible to the consumer due to its high cost.
Another method used is electrochemical sensors, in which semiconductor metal oxides or conductive polymers are used (Trends in Analytical Chemistry. 2012, 32, 87). They are based on the absorption of sulfide by the metal oxide producing an electrical signal that can be monitored in real time. However, in many cases they present considerable problems of stability to environmental factors.
Optical sensors have advantages in terms of their applicability and functionality; they allow in many cases a detection in real time and in the Play of origin (in situ), with a null energy cost. That is why they tend to be the most used among the general population because of their cost, simplicity and quick response. Lead acetate strips are an example: in the presence of sulphides, they change from white to gray / black, forming lead sulfide (PbS). The detection limits are in the range of 5-10 mg / L (ppm) and their utilization, although frequent, is not entirely recommended, due to the toxicity of lead that is neurotoxic (Journal Air Pollution Control Association 1966, 16, 328). Commercial colorimetric tubes can also be used, allowing hydrogen sulfide to be detected in lower concentrations 0.2-5 mg / L, although with low reproducibility. Colorimetric tubes require active sampling with an external energy source, which means specific sampling equipment and an energy cost to consider.
As passive sensor is described in Anal. Chem. 2016, 88, 1553-1558 a sensor that allows to determine only hydrogen sulfide in low concentrations. The sensor is a sheet of paper coated with Bi (OH) 3 or its alkaline derivatives at pH = 11, and requires a previous stage of conditioning the sensor by adding NaOH. In the presence of gas, the sensor changes color from white to yellow / brown. Although it has good characteristics, there is no data on its selectivity against other gases, nor on its response in real samples or atmospheres.
It has also been described in ACS Appl. Mater Interfaces 2014, 6, 6300-6307 the detection of hydrogen sulfide in air using gold nanoparticles, with a visual detection limit of 0.5 ppm. In this case, a sample of the gas to be analyzed is made
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Bubble in an aqueous solution to which the gold nanoparticles are added, which are not immobilized on any support, allowing the solutions to incubate for a few minutes. Finally, the solutions are subjected to UV-visible spectrometry measurements.
The use of nanoparticle films having incorporated metal ions for the detection of volatile sulfur compounds has also been described in US 2009/0140752 A1. Although many metal ions are cited as of possible use in that document, however the experimental tests are carried out only with films incorporating gold ions.
Finally, Sensors and Actuators B 2016, 228, 4 71-479 describes the use of colloidal silver nanoparticles in solution for use in the detection of organo-sulfur compounds released during the decomposition of onions. The nanoparticles of this document are spherical silver particles coated with polyethylene glycol and trisodium citrate, about 3-4 nm of medium size, and are used in the form of a colloidal suspension in a tube placed at the gas outlet of a desiccator where they are placed Onions in the process of decomposition. In this document, the inventors did not observe visual changes in the color of the silver nanoparticles during the first two days, the coloration developing in the following days until the tenth.
Consequently, the problem to be solved in the present invention is to provide a solid colorimetric sensor for the determination of volatile sulphide compounds that improves the characteristics of the sensors known in the prior art, and specifically that enables a simple detection, with Good sensitivity, portable (in situ) and passively in just 10 min. This sensor has a suitable selectivity for the monitoring of volatile sulfur compounds and it has been observed that other volatile compounds such as amines, ethanol or acetone do not interfere with the detection. The sensitivity is good, with a detection and quantification limit of 45 ppb v / v and 150 ppb v / v respectively by diffuse reflectance. The sensor has been tested in 10 healthy volunteers for the detection of bad breath, in 4 of them before and after the intake of foods rich in H2S (garlic) as responsible for the increase in volatile sulphide levels. It has also been successfully applied to the detection of sulfides in pipes. It is a sensor that does not present any toxicity, allows a direct detection of sulfides, in the place of origin and in real time. Finally, in addition to the above, this sensor has one of the lowest costs in the market for the detection of volatile sulphides at low concentrations.
The solution to this problem is based on the fact that the inventors have found that it is possible to obtain a colorimetric sensor with the indicated advantages by immobilizing silver nanoparticles of a size between 10 and 40 nm in a nylon membrane with a size Pore less than 8 microns, preferably between 0.22 and 1 micron, more preferably between 0.22 and 0.47 microns, and most preferably around 0.47 microns.
Consequently, in a first aspect the invention is directed to a passive colorimetric sensor for the detection and / or determination of volatile sulphides in gases comprising silver nanoparticles with a diameter between 10 nm and 40 nm, immobilized on a nylon membrane that It has a pore size between 0.22 and 1 microns.
In a second aspect, the invention is directed to a method of manufacturing a passive colorimetric sensor for the detection and / or determination of volatile sulphides in gases,
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comprising the step of passing a suspension of silver nanoparticles through a filter containing a nylon membrane, so that the silver nanoparticles are deposited and immobilized on said membrane. For this, in a preferred embodiment a volume of silver nanoparticles of the required diameter is taken, for example with a plastic syringe, and then the silver nanoparticles are passed through a filter containing the nylon membrane, where they remain immobilized If necessary or convenient, the rest of the suspension of nanoparticles that have not been immobilized can be re-passed through the filter in order to achieve a greater amount of nanoparticles therein.
In a third aspect, the invention is directed to a method of detection and / or determination of volatile sulphides in gases comprising the steps of:
a) exposing the sensor described above to a gas containing volatile sulphides for a time between 2 and 60 minutes, preferably about 10 minutes;
b) remove the sensor and determine its coloration by visual inspection, diffuse reflectance or RGB color analysis of a digital image of the exposed sensor;
c) from the data obtained in step b), determine the concentration of volatile sulphides in the gas by means of calibration lines or color patterns.
In a fourth aspect, the invention is directed to the use of the passive calorimetric sensor for the detection and / or determination of volatile sulphides in gases such as the atmosphere, closed enclosure atmospheres such as those in which gas evolution occurs due to of, for example, the storage of plant products, the crushing of farm animals, the wastewater treatment facilities, landfills, drains and drains, as well! as in the human breath for the detection of halitosis.
Brief description of the Figures
Figure 1: Explanatory scheme of the process of aggregation of the silver nanoparticles of the sensor of the invention in the presence of volatile sulphides.
Figure 2: Representation of absorbance values as a function of wavelength for 20 nm silver nanoparticles immobilized on membranes of A) nylon (left figure), B) fiberglass (central figure) and C) cellulose paper (right figure) in H2S concentrations of a) 0 ppb (v / v), b) 250 ppb and c) 1000 ppb (v / v). The photographs of the sensors and their response in the presence of H2S at 1000 ppb (v / v) have been added.
Figure 3. Photograph of the sensors and obtaining the calibration curve by representing the ratio between absorbance at 550 nm and 415 nm against the logarithm of the following H2S concentrations: a) 0, b) 150, c) 250, d) 500, e) 1000, f) 1500, g) 2500 ppb v / v.
Figure 4. A) Values obtained from the calibration curve for 10 healthy volunteers. B) Values obtained for 4 healthy volunteers before (left column) and after (right column) the intake of H2S-rich foods.
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Detailed description of the invention
The objective of the present invention is to provide a passive colorimetric sensor for the determination of volatile sulfur compounds in low concentrations with applications in the field of health, detection of bad breath that may be related to periodontitis or gingivitis (Sensors and Actuators B 2009, 136, 73), and also with environmental applications, the control of hydrogen sulfide in critical places (sewage treatment, landfills, drains, drains, oil processing, etc.) in order to comply with established regulations in this regard (Royal Decree 678/2014). In general, the sensor is usable for the determination of sulfur in any type of matrix in which the formation of this type of compounds exists or is generated. To date no sufficiently sensitive and selective sensors have been described that allow for on-site and real-time monitoring.
The need for this type of sensors has been solved using silver nanoparticles immobilized on a nylon membrane. Silver nanoparticles interact with sulfides (R-S- and S-2) due to the affinity of silver for sulfur. The result of this interaction causes color changes, from yellow to ocher / brown. According to the inventors, the silver nanoparticles are added as a result of the presence of sulfur compounds, which causes the characteristic band of the polydisperse silver nanoparticles, located at a wavelength of 415 nm, to travel at greater lengths wavelength (550 nm) and get wider as the degree of aggregation increases in a direct relationship with the concentration of sulfides (-S2- and RS-), as seen in the explanatory scheme shown in the Figure 1. However, it has now been surprisingly found that this effect varies in a very remarkable way depending on which substrate the nanoparticles are immobilized, so that, when immobilized on nylon membranes, a much greater retention of nanoparticles is obtained of silver, and also the sensors have a more intense yellow color, than when other supports such as cellulose paper or fiberglass are used. In addition, the optimum pore size of the nylon membrane has also been determined, this being less than 8 microns, preferably between 0.22 and 1 microns, and more preferably between 0.22 and 0.47 microns. In the present invention it is possible to use silver nanoparticles with a size between 10 and 60 nm, although the sizes between 10 and 40 nm are preferable, and even more preferred the sizes between 10 and 20 nm, for having a greater sensitivity.
This sensor has the advantages of a portable and passive solid sensor, so it does not require an external energy source, nor does it pre-prepare or pre-treat. The answer is obtained in just 10 minutes. In a preferred embodiment of the invention, at this time (i.e., after exposure to the sample of gases containing sulfides) the sensors are impregnated with glycerol, which is intended to improve the color reading, especially when It does by visual inspection. This impregnation is preferably done by adding a few drops of glycerol (about (50 pL) in the center of the sensor and spreading them with a rod or spatula, so that it is well distributed throughout the surface of the sensor. The impregnation with glycerol should be done after the exposure of the sensor to gases containing sulfides, since the inventors have found that, if done before, the sensors show no response, which is believed to be due to the fact that in these circumstances the AgNPs are not added.
One of the main problems of the use of silver nanoparticles, unlike other nanoparticles such as gold, whose synthesis and behavior is known in more detail, is the obtaining of nanoparticles with good size dispersion. To avoid this problem, commercial nanoparticles have been used in embodiments of the invention in order to avoid the said problems of irreproducibility
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which could come from non-polydisperse particles, which directly affect the sensitivity and seiectivity of the sensor.
After sampling, the sensor is preferably impregnated with glycerol, obtaining an increase in color intensity. Researchers believe that glycerol stabilizes silver nanoparticles. The impregnation with glycerol is not, however, an essential element for the invention, but only increases the intensity of the color and consequently the sensitivity of the process. The invention could also be carried out without the impregnation with glycerol, which will only result in an increase in the limits of detection and determination of sulphides by the sensor.
Once the sensor is colored, the intensity of the color can be monitored by visual inspection, by digital analysis of the red, green and blue (RGB) color values of a photo of the sensor obtained by means of a recording or image capture device such as a mobile phone, as well as diffuse reflectance.
Another of the main problems of using silver nanoparticles is their stability against external factors such as light. This problem has been solved by immobilizing the nanoparticles in nylon membranes; This keeps them stable for 3 months at room temperature.
Experimental examples
Example 1: Sensor optimization
As mentioned, the sensor design is based on the immobilization of commercial citrate-coated silver nanoparticles (Aldrich, dispersion of 0.02 mg / mL of 10, 20 or 40 nm silver nanoparticles of particle size (TEM ) stabilized with sodium citrate in aqueous buffer) on a membrane or support.
Different supports were tested for immobilization: nylon, cellulose paper and fiberglass. It was observed that the nylon had a greater retention of the nanoparticles and the sensors had a more intense yellow color, while the particles immobilized in the fiberglass were added forming small crystals. The sensors were tested against H2S gaseous patterns of 250 and 1000 ppb (v / v). Only the sensor prepared in nylon support showed a different response for each concentration, see Figure 2.
Once the nylon membranes were selected as the most preferred support, they were tested with different pore sizes in them. Experimental results showed that the retention of silver nanoparticles, as well as the sensitivity of the method, was similar for membranes with a pore size between 0.22 and 0.47 microns. However, when using membranes with a pore size of 8 microns, the retention was lower, giving rise to lighter yellow sensors, so it was more difficult to distinguish the color change.
Citrate-coated silver nanoparticles of different sizes of diameter were immobilized: 10 nm, 20 nm and 40 nm. All of them gave a positive response to the presence of different concentrations of sulfur, changing the sensor from yellow to ocher and then brown. The sensitivity was similar for the 10 nm and 20 nm nanoparticles (LOD = 45 ppb), while for the 40 nm nanoparticles a worse sensitivity was observed (LOD = 200 ppb).
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Different techniques were used for the immobilization of silver nanoparticles in different supports: by deposition, by immersion and by filtering. The best results were obtained by filtering, and the sensors showed a higher color intensity, with a much shorter preparation time (a few minutes).
Example 2: Sensor Preparation
A plastic syringe (2 mL) was taken, a plastic filter was attached and a nylon membrane, previously cut to the size of the filter, was incorporated so that the membrane occupied the entire surface of the filter. Then, between 0.2 mL and 1 mL of silver nanoparticles coated with commercial Aldrich citrate of 20 nm in diameter and 0.02 mg / mL of concentration in AgNPs were taken with the syringe, and passed through the filter with the nylon membrane incorporated therein. Once the nanoparticles were passed through the filter, the excess dispersion was passed through the membrane twice more, in order to retain as many silver nanoparticles as possible, reaching a retention of about 60% of the Silver nanoparticles (0.0024 ± 0.0002 mg for the tested conditions of 0.2 mL of dispersion taken with the syringe). Finally, the sensors were covered with a film (parafilm) and stored at room temperature.
Example 3: Generation of gaseous sulfide standards
In order to evaluate the response of the sensor to different concentrations of volatile sulphides, a series of sulfide patterns in air were generated taking as a model several studies in which the sulfide atmosphere is generated by adding an acid solution to a sulfide solution sodium (Na2S) or sodium methylmercaptan (CH3SNa). The added acid facilitates the volatilization of the sulfide compounds.
For this, sulfide solutions of known concentrations as! as an 85% phosphoric acid solution. To generate the corresponding atmosphere, 2 L static dilution bottles fastened by the neck were used with a foot clamp or stand and on an agitation system. In the first place, the stirrer magnet and the sensor to which it is spoken were passed into the bottle, so that it was hanging inside the static dilution bottle. Then 0.1 mL of 85% phosphoric acid was added and the bottle was capped. Finally, an aqueous solution of sodium sulphide of 50 mg / L was added with a syringe through the septum of the static dilution bottle and left under stirring for 10 minutes. After ten minutes, the sensor was impregnated with glycerol and its analytical response was measured by diffuse reflectance or the digital image of the sensor was obtained and the RGB color analysis was performed, obtaining the corresponding values.
Example 4: Evaluation of the sensor response to gaseous sulfide patterns
The response of the sensors to volatile compounds such as hydrogen sulfide (H2S), methyl mercaptan (CH3SH) and dimethylmercaptane ((CH3) 2S) was then evaluated, with hydrogen sulfide and methyl mercaptan being primarily responsible for Halitosis The sensor presented a positive response to hydrogen sulfide with detection and quantification limits of 45 ppb (v / v) and 150 ppb (v / v) respectively, while for methylmercaptane the detection and quantification limits were 200 ppb ( v / v) and 666 ppb (v / v), respectively. No response was observed due to the presence of dimethylmercaptan.
Figure 3 shows the ratio between absorbance at 550 nm (corresponding to the maximum of the band of aggregated nanoparticles) and absorbance at 415 nm
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(corresponding to the maximum of the band of the silver nanoparticles without adding) against the logarithm of the hydrogen sulfide concentration at 0, 150, 250, 500, 1000, 1,500, 2,500 ppb (v / v). The sensor response can be followed by diffuse reflectance, by visual inspection as can be seen in the photograph, and also by RGB analysis of the photograph taken using a mobile device. The calibration line obtained by diffuse reflectance was as follows:
A550 / A415 = (0.3 1 ± 0.02) Log Cppb (v / v) - (0.58 ± 0.05), R2 = 0.990 (equation 1)
It was also possible to obtain a calibration line by means of the RGB analysis of the photo taken:
RGB of red = (-0.056 ± 0.0 18) C (ppb v / v) + (253 ± 3), R2 = 0.991 (equation 2)
The response of the sensors was evaluated at different exposure times. An exposure time of 10 minutes was chosen as a compromise between the intensity of the signal obtained and an adequate sampling time.
Example 5: Evaluation of the sensor response in real samples
To assess whether the colorimetric sensor can be applied for the detection of halitosis, 10 healthy volunteers were blown independently into plastic bags used for air sampling, in which the sensor was previously introduced inside. After 10 minutes of being in contact with the breath of the volunteers, the sensor was extracted, impregnated with glycerol, the digital image was obtained and the same was processed obtaining the RGB color coordinates and / or its color intensity was measured by diffuse reflectance. The results obtained are shown in Figure 3, where it is observed that the concentrations obtained are below the concentrations considered as persistent bad breath or severe halitosis.
In addition, a study was made on the effect of the intake of foods rich in H2S on the breath. Garlic is traditionally used in Mediterranean cuisine and has very beneficial properties for the body, the most known being its power as an antibiotic. However, the consumption of this food causes bad breath due to the presence of volatile sulphides. In this study, 4 volunteers were evaluated before and after eating a garlic-rich sauce. Figure 4B shows how volatile sulfide levels effectively increase immediately after consuming this product.
The samples were then fortified, that is, an amount of 0, 250, 300 or 500 ppb of sulfide was added thereto. For this, volumes of 0-100 pL of a standard solution of 50 mg / L of Na2S, and 100 pL of 85% phosphoric acid were used in plastic bags of a capacity of 2 L where the volunteer had previously blown. 10 m in were expected, the sensors were removed from the bags and impregnated with glycerol. Finally, the digital images were obtained and / or the sensors were measured by diffuse reflectance.
Table 1 shows the results obtained for the recovery in% of the indicated samples. Recoveries in% were calculated as follows:
- A (column 1): Fortification or added amount of sulfur (ppb) to the samples;
- B (columns 2, 4, 6 and 8): Detection (in ppb) of the fortified sample. This concentration is obtained from the measurement of the color of the sensors and their
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interpolation in the corresponding calibration line according to the method used, that is, diffuse reflectance or RGB analysis of the digital images (in the calibration lines equations 1 and 2, respectively).
- C (first row at ppb = 0): Concentration of sulphides in the sample calculated from the measurement of the color of the sensors by diffuse reflectance and their interpolation in the calibration line that is equation 1. Values 145 were obtained and 116 ppb for volunteer 1 and volunteer 2, respectively. The values were also calculated using the RGB analysis of the red color of the digital images using the GIMP software (equation 2). The values obtained were 151 and 115 ppb for volunteer 1 and volunteer 2, respectively.
So:
Recovery (%) = (B-C) / A x 100
For example, for a fortification of 250 ppb:
Recovery (%) = (392-145) 1250 x 100 = 99%
 Volunteer 1  Volunteer 2
 Samples fortified in (ppb) 0 250 300 500  Diffuse reflectance Digital images (GlMP) Diffuse reflectance Dig images: such (G! MP)
 Detection Recovery (ppb) (%)  Detection Recovery (ppb) (%) Detection Recovery (PPb) <%) Detection Recovery (ppb) (%)
 145 392 99 506 113 666 103  151 367 91 475 105 601 92 116 429 117 464 111 672 109 115 349 96 421 101 637 103
Table 1: Values and recoveries of 2 fortified samples of healthy volunteers obtained by diffuse reflectance and by the RGB of the sensor photographs.
The results demonstrate that the colorimetric sensor of the invention is capable of detecting sulfides in gases through an easy, simple and fast way, by simple visual inspection. The developed sensor is a solid, light and portable device, which has good detection and quantification limits - 45 ppb v / v and 150 ppb v / v, respectively, by diffuse reflectance - and can be applied for the detection / control of the severe halitosis It is an ecological sensor, does not present any toxicity to both people and the environment, its manufacturing cost is low and has a useful life of 3 months.

权利要求:
Claims (14)
[1]
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1. Passive calorimetric solid sensor for the detection and / or determination of volatile sulphides in gases comprising silver nanoparticles with a diameter between 10 nm and 40 nm immobilized in a nylon membrane having a pore size between 0.22 microns and 1 micron
[2]
2. Sensor according to claim 1, wherein the silver nanoparticles have a diameter of 20 nm.
[3]
3. Sensor according to claims 1 or 2, wherein the silver nanoparticles are stabilized with sodium citrate.
[4]
4. Sensor according to any one of claims 1 to 3, wherein the nylon membrane has a pore size of 0.47 microns.
[5]
5. Sensor according to any one of the preceding claims that is impregnated with glycerol after exposure to volatile sulphides in gases but before detection and / or determination.
[6]
6. Method of fabrication of the passive solid calorimetric sensor of any one of claims 1 to 5 above comprising passing a suspension of silver nanoparticles with a particle diameter between 10 nm and 40 nm through a nylon membrane having a size pore between 0.22 microns and 1 microns, so that at least a part of the silver nanoparticles are deposited and immobilized on said membrane.
[7]
7. Method according to claim 6, comprising the following steps:
a) provide a 2 mL plastic syringe to which a filter is attached;
b) insert the nylon membrane cut to the size of the filter into the filter; Y
c) passing through the nylon membrane an amount between 0.2 mL and 1 mL of a dispersion of silver nanoparticles having a concentration of silver nanoparticles of 0.02 mg / mL.
[8]
8. Method according to claim 7 wherein, after step c), the part of the dispersion of silver nanoparticles that has not been retained in the nylon membrane is collected and passed through the membrane Up to two or three more times.
[9]
9. Method of detection and / or determination of volatile sulphides in gases or in matrices that emit volatile sulphides, comprising the steps of:
a) exposing the sensor of any one of claims 1 to 5 to a gas or matrix emitting volatile sulfides for a time between 2 and 60 minutes;
b) remove the sensor and determine its coloration by visual inspection, diffuse reflectance or RGB color analysis of a digital image of the sensor;
c) from the data obtained in step b), determine the concentration of volatile sulphides in the gas by means of calibration lines or color patterns.
[10]
10. Method of detection and / or determination of volatile sulphides in gases according to revindication 9 which comprises the additional step of impregnating the sensor with glycerol after exposure to the gas containing volatile sulphides but before its detection and / or determination .
5
[11]
11. Method according to revindication 10, in which the impregnation of the sensor with glycerol is performed by depositing a few drops of glycerol on the sensor and spreading it with a spatula or rod in order to distribute it homogeneously throughout the sensor surface.
10. Method according to any one of claims 9 to 11 wherein the gases which
They contain volatile sulphides from human respiration.
[13]
13. Use of a sensor according to any one of the preceding claims 1 to 5 in the detection and / or determination of volatile sulphides in gases or in any
15 matrix in which volatile sulphides exist or are generated.
[14]
14. Use according to revindication 13 in which the gases come from the atmosphere or from closed or open enclosures.
20 15. Use according to revindication 14 in which the enclosures are selected from enclosures
for the processing and refining of oil or natural gas, sewage treatment plants, landfills, drains and drains.
[16]
16. Use according to revindication 13, in which the gases come from human respiration 25, for the determination of halitosis.

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Cvitešić Kušan et al.2019|Electrochemical evidence of non-volatile reduced sulfur species in water-soluble fraction of fine marine aerosols

---

Li et al.2021|Fabricating a nano-bionic sensor for rapid detection of H2S during pork spoilage using Ru NPs modulated catalytic hydrogenation conversion

---

Qiao et al.2014|Overlapping of second order scattering and frequency double scattering spectra method and resonance Rayleigh scattering method for the determination of 6-benzyladenine in bean sprout

---

Makino et al.2009|Nondestructive analysis of chlorpyrifos on apple skin using UV reflectance

---

Hosnedlova et al.2020|Study of physico-chemical changes of CdTe QDs after their exposure to environmental conditions

---

Ahn et al.2021|Rapid and simple colorimetric detection of hydrogen sulfide using an etching-resistant effect on silver nanoprisms

---

Xia et al.2013|Ce |-induced rice mitochondrial permeability transition investigated by spectroscopic and microscopic studies

---

Hurst et al.2003|The utility of the nitric oxide electrochemical sensor in biomedical research

---

WO2014181012A1|2014-11-13|Passive device for the detection and/or determination in situ of amines in gases

同族专利:

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公开号 | 公开日

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EP3467476A4|2020-03-25|

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ES2643857B1|2018-09-06|

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WO2018015607A1|2018-01-25|

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EP3467476A1|2019-04-10|

引用文献:

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公开号 | 申请日 | 公开日 | 申请人 | 专利标题

---

---

WO1997005482A1|1995-07-31|1997-02-13|The Oralife Group, Inc.|A colorimetric method of detecting thiol or mercaptan compounds and its use for oral malodor determination|

---

US20120058697A1|2009-04-01|2012-03-08|Strickland Aaron D|Conformal particle coatings on fiber materials for use in spectroscopic methods for detecting targets of interest and methods based thereon|

---

WO2010151329A1|2009-06-24|2010-12-29|Seventh Sense Biosystems, Inc.|Assays involving colorimetric signaling|CN110031456B|2019-04-04|2022-01-25|青岛大学|Preparation method and application of green sol test paper for rapidly detecting sulfur ions|

---

CN111220612A|2020-02-20|2020-06-02|江苏大学|Method for detecting hydrogen sulfide in pork based on nano color-sensitive bionic sensing technology|

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ES201600440A|ES2643857B1|2016-05-24|2016-05-24|Colorimetric sensor based on silver nanoparticles for the determination of volatile sulfide compounds|ES201600440A| ES2643857B1|2016-05-24|2016-05-24|Colorimetric sensor based on silver nanoparticles for the determination of volatile sulfide compounds|

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PCT/ES2017/070532| WO2018015607A1|2016-05-24|2017-07-21|Colorimetric sensor based on silver nanoparticles for the determination of volatile sulfur compounds|

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EP17830545.4A| EP3467476A4|2016-05-24|2017-07-21|Colorimetric sensor based on silver nanoparticles for the determination of volatile sulfur compounds|