Composition and device for detecting GHB in liquids and method for preparing the device

Abstract

The invention relates to a composition comprising water-based screen-printing ink, an acidity-regulating compound that is a weak acid, an organic dye with a different colour depending on the pH, changing colour in the pH range from 3 to 8, and an organic solvent, which detects the presence of gamma-hydroxybutyrate (GHB) in liquids such as beverages by means of a colour change with speed and specificity and also allows the preparation of GHB detection devices comprising a support to which said composition is affixed by screen-printing, such as devices in the form of bracelets. The devices are easily portable and simple to use and prepare, therefore providing a useful alternative for detecting GHB in beverages in places of entertainment.

Description

[0001] DESCRIPTION

[0002] Device for detecting GHB in liquids and method for preparing the same

[0003] Field of invention

[0004] The present invention relates to the field of devices for detecting compounds for easy use in everyday life. More specifically, the invention relates to a portable device for detecting GHB in liquid samples, particularly beverages, using a colorimetric system affixed to the device by screen printing.

[0005] Background of the invention

[0006] Gamma-hydroxybutyric acid (GHB), also known as 4-hydroxybutyric acid, 4-hydroxybutanoic acid, or oxibic acid, is a short-chain hydroxylated carboxylic acid that occurs naturally in some berries and is also produced in small quantities in the nervous system of mammals and in alcoholic fermentation processes such as those used in wine and beer production. Currently, it is also produced synthetically, for example, from gamma-butyrolactone (GBL) or tetrahydrofuran (THE). It is a compound readily soluble in water and sparingly soluble in organic solvents and lipids, with the molecular formula C4H8O3, a molecular weight of 104.1 g / mol, and a pKa of 4.72.

[0007] Its deprotonated form, gamma-hydroxybutyrate or oxybate, primarily its sodium or potassium salts, is used in medications to control the symptoms of narcolepsy, insomnia, or excessive daytime sleepiness, as well as a neuroprotective dietary supplement. GHB and its sodium salt have the following chemical formulas:

[0008] GHB (gamma-hydroxybutyric acid) sodium gamma-hydroxybutyrate

[0009] Currently, it is also known for its use as a date rape drug, a use that has been a cause for concern since the first cases of abuse were reported in the early 1990s. GHB is rapidly eliminated from the body, with a plasma half-life of only 20 to 45 minutes, which complicates the collection of samples in time to confirm its use.

[0010] Despite these challenges, more recent reports show an increase in GHB poisonings at social events such as raves and parties, where it is often used as a recreational drug referred to as liquid ecstasy. A GHB concentration of 90 mM in a drink is sufficient to have effects on the body. Because GHB is colorless, odorless, and tasteless, it is almost undetectable when mixed with beverages, making it an ideal facilitator for drug-facilitated sexual assault (DFSA). Its effects, which include disinhibition, dizziness, amnesia, and loss of consciousness, leave victims extremely vulnerable, especially in the context of drug-facilitated sexual assault (DFSA).

[0011] To address this problem, efficient GHB detection is essential. Current detection methods include laboratory tests, both colorimetric and enzymatic assays, as well as advanced instrumental techniques such as liquid chromatography-mass spectrometry (LC-MS). These methods offer high sensitivity and accuracy, but their implementation remains limited by high costs and the need for specialized equipment (Ingels et al., 2014). Furthermore, these methods help confirm the presence of GHB after the fact, when its presence is suspected, in most cases after the assault has already occurred. Therefore, developing in situ methods for the detection of date rape drugs has become vitally important. Some of these methods, as well as related laboratory procedures, are described below.

[0012] Colorimetric tests in the laboratory

[0013] The colorimetric detection of gamma-hydroxybutyric acid (GHB) in biological samples and beverages has advanced considerably, with rapid and simple methods for identifying its presence. Badcock and Zotti (Badcock and Zotti, 2008) developed a colorimetric test that converts GHB to its lactone, GBL (gamma-butyrolactone), generating a color change in the sample. Although rapid, this method has low sensitivity, with relatively high detection limits, which hinders its use at low GHB concentrations. On the other hand, Baumes et al. (Baumes et al., 2010) created a sensor based on supramolecular complexes with fluorescent dyes, which allows the specific detection of GHB in aqueous media, useful for its identification in recreational settings. More recently, Rodríguez-Nuévalos et al. (Rodríguez-Nuévalos et al., 2021) developed chemosensors that interact with functional groups of GHB through two distinct functional groups (a trifluoroacetyl group and a thiourea), allowing the detection of GHB in drinks and urine, with lower detection limits, but requiring preconcentration in urine due to the low concentrations of the compound in this sample.

[0014] Enzyme assays in the laboratory

[0015] Enzymatic assays based on GHB dehydrogenase (GHB-DH) are effective for the detection of gamma-hydroxybutyric acid (GHB) due to their specificity and quantification capabilities. These methods are based on the oxidation of GHB to succinic semialdehyde (SSA) by GHB-DH, an oxidation that occurs with the simultaneous reduction of NAD+. +assisted by the release of a proton from the oxygen atom of the OH group. This enzymatic reaction is coupled to reactions that produce changes in analytical signals such as fluorescence or absorbance, allowing for precise measurement. They are useful in forensic and clinical settings, where speed and reliability are required (Ingels et al., 2014).

[0016] Enzymatic colorimetric assays in the laboratory

[0017] Enzymatic colorimetric assays, such as those developed by Bravo et al. (Bravo et al., 2020), allow for the detection of GHB through an enzymatic reaction coupled to the oxidation of GHB to SSA. This coupled reaction, mediated by a diaphorase, generates a visible color change due to the reduction of a tetrazolium pro-dye, making detection easy and accessible. However, these assays have a limitation in sensitivity, as they require a minimum concentration of 100 pg / ml of GHB to ensure positive results, which may restrict their use in the early stages of intoxication.

[0018] International patent application W02013041718A1 also describes a method for detecting GHB based on the conversion of this compound to SSA by hydroxy acid-oxo acid transhydrogenase (HOT) in the presence of alpha-ketoglutarate and the detection of SSA formation using a colored product (e.g., an azine formed from an azone, which may be 3-methyl-2-benzothinzolinone-2-hydrazone, abbreviated as MBTH). Detection is performed by optical, colorimetric, or spectrometric methods, depending on the colored product formed. Chromatographic screening techniques

[0019] Chromatographic methods, such as GC-FID (gas chromatography coupled to a flame ionization detector) and GC-MS (gas chromatography coupled to mass spectrometry), are highly specific for GHB detection but require complex preparation, such as derivatization or conversion of GHB to GBL. In studies such as that by Lebeau et al. (Lebeau et al., 2000), GC-FID with headspace injection of biofluids was used for initial detection, which was then confirmed by GC-MS. This approach is suitable for diagnosis and treatment in clinical settings.

[0020] Urine assays using silylation and GC-MS also allow for the detection of GHB, but acidification of the sample can reduce the signal by converting GHB to GBL. To improve accuracy, interference from silylated urea can be resolved by treatment with urease.

[0021] Other laboratory detection techniques

[0022] Regarding other detection techniques, nuclear magnetic resonance spectroscopy ( 1 ν-NMR has been successfully used to detect GHB in biological fluids such as urine and serum, standing out for its non-destructiveness and minimal sample preparation. Ion mobility spectrometry (IMS) also shows great potential, with a low detection limit of 3 pg / ml, and capillary electrophoresis with ultraviolet detection (CZE-UV) allows for the rapid detection of high concentrations of GHB in urine after a simple sample dilution (Ingels et al., 2014).

[0023] Although the methods mentioned so far have significant scientific value, their practical usefulness is limited, as they do not serve to prevent these crimes but rather to confirm, after the fact, the presence of this compound in the sample. Given the substance's short half-life and the public environments in which it is used and abused, detecting its presence in situ is a challenge. Until very recently, there was no field test that could be applied in the leisure and party settings where this drug is abused, although several techniques and devices are now available, which are discussed below. In situ detection: Fluorescent detection on paper

[0024] Recently, the team of Hernández-Contreras et al. (Hernández-Contreras et al., 2024) reported two new fluorescein-bound compounds, one based on 2-aminonaphthoxazole and the other on benzoxazole, which, in DMSO solution, are capable of detecting the presence of GHB in beverages through color changes or fluorescence. The test uses cellulose paper for the in situ fluorescent detection of GHB in water, soft drinks, and alcoholic beverages at concentrations sufficient to induce an effect on victims, with a detection limit of 7.3 mM.

[0025] On-site detection: Colorimetric Paper Sensor + Mobile Application

[0026] The colorimetric paper sensor described by Son et al. (Son et al., 2021) for detecting GHB in beverages works by detecting a color change from blue to red in the presence of this drug. This change is due to the chemical interaction between GHB and the detection materials, such as PCDA (10,12-pentacosadiynoic acid) and PCDA-gabazin, which interact with GHB. The thermoplastic polymers PEO (polyethylene oxide) and PVDF (polyvinylidene fluoride) are used as the matrix. These materials are said to enable GHB detection in short periods of time by increasing the penetration rate of liquid samples. The detection kits are manufactured by electrospinning from a solution containing the detection materials and the matrix materials. The kit allows for quick and easy detection of GHB in various types of beverages, including alcoholic ones.It is an economical and easy-to-use solution that provides a clear visual indication, which can be helpful in preventing unintentional GHB consumption.

[0027] However, this method has several limitations. Its sensitivity is moderate and it is only effective when GHB is present in sufficiently high concentrations, which may cause it to fail to detect lower doses of the drug that can also be dangerous. Furthermore, the reaction can be affected by other compounds present in the beverages, which could lead to false positives or negatives. Interpreting the color change can be confusing in poorly lit environments, and it does not allow for precise quantitative analysis, increasing the risk of obtaining incorrect results, especially if the GHB concentration is low. On-site detection: Coasters and Detection Cards (Drink Safe Technologies® and Aleo Prevention®)

[0028] The detection devices in the form of coasters and cards are designed to detect the presence of GHB in alcoholic beverages and soft drinks, as well as ketamine, another drug also used at raves or parties as a drug of abuse, although in a different part of the device. The commercial kits from Drink Safe Technologies (https: / / www.drinksafe.com / drink-test-kits / -), also marketed by Aleo Prevention under the name “Drink Detective®” (https: / / alcoprevention.com / en / product / drink-spiking-detection-test-for-ketamine-and-ghb-drink-detective / ), are based on the use of color-changing reagents on simple substrates such as cardboard, where a positive result is indicated by the appearance of a blue color.The devices appear to be based on the invention described in the international patent application published as W02003021254, where colorimetric indicators embedded in a surface with sufficient porosity for the solution to be tested (the beverage in real cases) to reach the colorimetric indicator are described, in which the presence of GHB is identified by the color change of the bromocresol purple colorimetric indicator (5',5-Dibromo-o-Cresolsulfonphthalein), a pH indicator whose transition range is between 5.2 and 6.8, varying from yellow to purple in the mentioned range.

[0029] These devices allow consumers to perform the test quickly and easily in public settings such as nightclubs or bars. They are inexpensive and easy to use, offering a discreet and practical way to detect drugs in drinks in social situations.

[0030] However, this method has several drawbacks. The main one is its low sensitivity, as it can only detect high concentrations of GHB, making it ineffective for identifying lower doses of the drug, which are still dangerous. Furthermore, the type of beverage can affect the accuracy of the result, since the beverage's composition (such as alcohol content) can interfere with the chemical reaction. In inadequate lighting conditions, interpreting the color change can be difficult, reducing the device's reliability. The recommended waiting time for the color change to occur with commercially available devices is several minutes, specifically two. Additionally, in field studies, the device's effectiveness rate was 65%, with a false-negative rate of 50%, raising concerns about the reliability of the results in real-world settings (Child and Child, 2007; Quest and Horsley, 2007).

[0031] Test Strips

[0032] Test strips like those marketed under the name Check Your Drink Technology®, by both Aleo Prevention Canada (https: / / alcoprevention.com / en / product / check-your-drink / ) and the company also called Check Your Drink (https: / / checkyourdhnks.com / product / cyd-matchbook-with-8-tests-strips / ), detect the presence of GHB and ketamine in beverages through a color change in the strip's patches. The pink patch turns blue if GHB is present, and the yellow patch turns orange if ketamine is detected. This method is quick and easy, providing immediate results that can be easily interpreted by the user.

[0033] The product claims to be based on research from the University of Strathclyde, so it appears to derive from the methodology included in international patent application WQ2013041718A1.

[0034] Despite their simplicity, reagent strips have several limitations. As with other methods, the effectiveness of these strips depends on the type of beverage being tested, since some complex matrices can interfere with the reaction and affect the accuracy of the result.

[0035] Card-based test (Drink Detective®)

[0036] The “Drink Detective®” card-based test, marketed by NotlnMyDrink (https: / / www.notlnmydrink.com / dhnk-detective / ), detects the presence of GHB and other drugs in beverages by detecting a color change on a cardboard card. The method for detecting GHB is the one developed by DrugLab118 (https: / / www.druglab118.com / #detection), the laboratory listed as the applicant in international patent application WQ05088297A1. This document describes a device for detecting the presence of gamma-hydroxybutyrate in a beverage. The device comprises, on a substrate, a combination of salts or, preferably, lacmoid, buffered preferably with hydrochloric acid and impregnated with a polar solvent such as acetone, methanol, or water, resulting in the appearance of a blue color in the presence of GHB. Thus, this method is based on a qualitative test that provides quick results, but with certain limitations.Although it offers high specificity under ideal conditions, its sensitivity can be affected by the type of beverage in which the test is performed. In studies conducted by Beynon et al. (Beynon et al., 2006), the sensitivity of Drink Detective was 69%, with a false negative rate in water, where GHB was not detected, suggesting that the test may not be effective in detecting the drug in some beverages.

[0037] This method can also create a false sense of security, as results can be misinterpreted in nighttime and poorly lit environments. The false negative rate is a significant problem, as it can lead users to believe that a beverage does not contain GHB when it actually does, increasing the risk of intoxication (Child and Child, 2007).

[0038] drop test kit

[0039] The Overdrive test kit (https: / / www.overdrivedefense.com / products / drink-spike-test-kit) has a different format than usual, as it includes two droppers, two vials, and two test cards. The test procedure involves two steps: the user first mixes two drops of the beverage sample into a vial, shakes it for 5-8 minutes, and then places one or more drops onto the test device, the test card. It is then necessary to wait 5 minutes for the result, which is the appearance of a pinkish-purple color. The complexity of the procedure makes it unsuitable for real-world use.

[0040] Drugcheck® Strip Test

[0041] The commercially available Drugcheck® urine drug test strip (https: / / www.drugcheck.com / urine-drug-testing) detects GHB in human urine with a cutoff level of 10 pg / ml. Results are obtained within 10 minutes, and interpretation is based on a color chart on the test strip, along with a separate test strip for vitamin C, a compound with which cross-reactivity may occur in the GHB test.

[0042] Although this GHB test strip is more sensitive and can detect lower concentrations of GHB, it only provides a preliminary result and does not indicate the level of intoxication. On-site detection in a wristband format.

[0043] Wristband drug testing for date rape drugs has gained popularity due to its convenience, discretion, and ease of use. These systems allow users to perform tests quickly and easily in social settings, such as bars or nightclubs. The following describes some current wristband-based products and their features, highlighting their advantages and limitations.

[0044] On-site detection in wristband format: Xantus Drinkcheck KO Drop® wristband

[0045] The Xantus Drinkcheck KO Drop® bracelet, from the company Xantus (https: / / www.xantus-drinksafe.de / ), and marketed by companies such as Aleo Prevention Canada (https: / / alcoprevention.com / en / product / xantus-drinkcheck-ko-drop-bracelet / ), offers a simple and discreet way to detect the presence of GHB. To use it, the user places one or two drops of the suspected beverage onto a test area of ​​the bracelet. After waiting between 30 seconds and 2 minutes, if the test area turns blue, this indicates that the beverage has been spiked with GHB. The process is quick, easy, and discreet, making this device ideal for social situations where the user may not be constantly monitoring their drink.

[0046] However, despite its simplicity, the wristband has several limitations. One is that false positives can occur if the wristband gets wet, including with rainwater. The main limitation is that it doesn't provide a quantitative measurement of the amount of GHB present in the drink, which can create a false sense of security if the drug concentration is low. Furthermore, although the waiting time is relatively short, the test still relies on the sensitivity of the wristband's testing area, which can affect its reliability in drinks with complex matrices or minimal drug concentrations.

[0047] The internet addresses listed above, referring to this product, do not specify the compound or compounds that cause the color change or the method used to prepare the bracelet. However, the founders of the company Xantus are the inventors listed in the family of international patent application WO2021064172A, to which US application US2024053310A1 also belongs, and which describes a bracelet-shaped device consisting of a band with two ends configured to join together, the band including or formed from a test strip that includes at least one area comprising a dry chemical substance with a hue that changes when drops of a beverage containing a date rape drug such as GHB are added to its surface.When the wristband is made of a single piece of material, it preferably includes at least one opening to allow viewing of the test area of ​​the test strip. The possibility of inserting the test strip between two layers is also considered, each layer including an opening for the test area and a second opening for inserting and removing the test strip. The wristband may comprise paper, the polymeric material marketed under the Tyvek® brand, silicone, a synthetic material, natural fibers, or leather, and its upper and lower surfaces are configured to be printed. However, the application does not specify any compounds that may be used to produce the desired color change, nor does it specify the wristband preparation process or how the compound or compounds responsible for the color change are bonded to the test strip.

[0048] On-site detection in wristband format: Drinks Guard® Wristband and Test Strips

[0049] The Drinks Guard® wristband and test strips, marketed by Farmasoler (https: / / www.farmasoler.com / drinks-guard-test-de-drogas-en-la-bebida-5uds-217672.html), are designed to detect the presence of GHB and ketamine in beverages. To use the Drinks Guard® wristband, the user places a small sample of the beverage on a test area of ​​the wristband or on a test strip. In just a few seconds, if the presence of the drug is detected, the test provides a visual indication, such as a color change. The system is effective even with small amounts of GHB or ketamine, making it a valuable option for environments where alcoholic beverages are consumed.

[0050] However, studies on the effectiveness of the Drinks Guard® wristband indicate that it has some limitations. In one study, the system's sensitivity was 37.5%, meaning that in a considerable percentage of cases, the drug was not detected when present. The specificity was 76.6%, indicating that, although the system is relatively effective at identifying contaminated drinks, there is still a significant margin of false positives. This could lead to confusion and a false sense of security among users, especially if the system is unable to detect the drug at lower concentrations, or if the drink contains other compounds that interfere with the test. Other devices and compositions detect different compounds by color change.

[0051] For the detection of other compounds, some additional different strategies can be found.

[0052] U.S. patent application US20220357349 describes a device for detecting at least one drug of abuse, selected from nicotine, cannabinoids, amphetamines, opioids, and cocaine, present in residues on vaping device surfaces and in vaping liquid formulations (oily / viscous e-liquids). The colorimetric agent and the catalytic agent are configured to undergo a chemical reaction in the presence of one of these drugs of abuse (in liquid, gel, or powder form), producing a visible color change in the reaction zone. The function of the catalytic agent is to increase the rate of color change in the reaction between the colorimetric agent and the drug of abuse, and it is described as an acid, mineral or organic, in liquid or solid form. Examples of acids in solid form include oxalic acid, citric acid, or sodium bisulfate.Examples of possible colorimetric agents include a long list of compounds commonly used as indicator agents, including bromocresol green, bromophenol blue, methyl red, chlorophenol red, and iodophenol blue (3',3”,5',5”-tetraiodophenolsulfonaphthalein), the latter being the preferred indicator.

[0053] The device can be prepared from a portable kit by mixing the colorimetric agent and the catalytic agent dry and fixing the mixture to a solid support to form a reaction zone. The kit should also contain an absorbent material, such as a cotton swab or wipe, which can be used to take a sample from a surface and transfer it to the reaction zone by rubbing it against it. Paper, including synthetic paper made of polypropylene or polyethylene, is a possible solid support. The material can be fixed to the solid support using various printing methods, including rotary screen printing and flat screen printing.

[0054] The reactive ink may contain 6–9 g of colorimetric agent, 50–70 g of catalytic agent, and 2–2.5 liters of alcoholic solvent, which may correspond to a weight ratio of 1:5:180 colorimetric agent: catalytic agent and alcoholic solvent, so that the reactive ink has the desired viscosity. The Examples in the application describe: a solution of 3',3",5',5"-tetraiodophenolsulfonaphthalein, citric acid, and methanol in a ratio of 1:5:100, which is fixed either onto a paper strip by immersion drying (Example 1) or onto synthetic polypropylene or polyethylene paper, by passing said paper through a large-scale printing machine adapted to a printing method, including rotary screen printing and flat screen printing (Example 2).Application US20220357349 does not include any evidence that demonstrates that the devices disclosed therein can actually be prepared as described in the application or that they function for the purpose for which they are designed.

[0055] Korean patent KR102076564B1 describes a composite material used in diapers comprising a waterproof film layer with an aqueous ink on one surface that changes color depending on the pH, becoming decolorized. This ink includes, among other compounds, water-soluble polymers and other resins such as rosin, a pH indicator, a pH-regulating organic acid, a solvent, a silane, and a binder. The polymers can be acrylic copolymers (35-45%); the binder can be acylates (1-5%); the pH indicator can be bromocresol green (2-10%); the organic acid citric acid (0.1-2%); and the solvents include isopropanol, water, or alcohol, among others (50-55%). The substrate on which the ink is printed can be non-woven fabric, and the printing technique can be screen printing.

[0056] For its part, international patent application WO2018169129A1 discloses an aqueous printing ink that changes color with pH, ​​suitable for flexography and gravure printing, comprising, among other compounds, water-soluble polymers (which may be acrylic copolymers), in a percentage of 0.5-3%, and other resins (such as ethylene or propylene oxides) in a percentage of 20-45%, a pH indicator (which may be bromocresol green) in a percentage of 2-10%, a pH-regulating organic acid (such as citric acid) in a percentage of 0.1-2%, a solvent (isopropanol or water) in a percentage of 50-70%, among others, and a binding agent (e.g., acylates) in a percentage of 1-5%.

[0057] The above compositions, which can be used as printing inks, have not been used so far for the detection of GHB.

[0058] In summary, it can be said that various devices for the on-site detection of GHB have been developed and are available on the market, but each has its own disadvantages. While some have a very high detection threshold, which can cause significant amounts of the compound present in beverages to go undetected, others have low specificity that can lead to false positives or rely on the appearance of signals that are difficult to detect in environments such as nightclubs, discos, or rave venues, or that take too long to appear. Some of the devices are made of materials that can be easily altered by spilled liquids (as is the case with devices with cardboard or even paper supports), which can cause the reagents intended for testing one drug, such as GHB, to be mixed with those of another drug being detected with the same device.In other cases, the detection system consists of several elements that are difficult to fit in a party bag, including droppers, vials, and test cards, and is complicated to use, requiring the user to perform several steps to obtain a result. In some other cases, the manufacturing process even requires very specific techniques, such as electrospinning, which complicate large-scale production and / or requires highly porous materials for the compound to reach the test zone within the device.

[0059] It would be interesting to have a composition that allows the rapid detection of the presence of GHB in beverages, with high specificity for this compound, easy to prepare and easy to use, in which the signal indicating the presence of the compound is easy to distinguish even in the low-light environmental conditions in which its use is usually necessary, and that is applicable to any beverage, regardless of whether it is colored or not, with or without alcohol, and is also easy to apply for the preparation of detection devices.Preferably, the composition should also be suitable for preparing devices that, in addition to meeting the aforementioned conditions for the composition, could be prepared in different formats, including alternatives with good portability and / or that can be carried discreetly and accessibly in any environment and that, at the same time, offer guarantees of stability in the face of common situations in recreational environments where drinks are consumed, such as spillage of liquids, perspiration, or excessive ambient humidity.

[0060] The present invention offers a solution to this problem.

[0061] Summary of the invention

[0062] In a first aspect, the invention relates to a composition, the composition of the present invention, characterized in that it comprises, per 100 ml: - 50-99 ml water-based screen printing ink

[0063] - organic coloring compound 2.5 - 10 g

[0064] - Acidity regulator 2.5 - 8.75 g, optionally, if necessary to complete the volume

[0065] - solvent to complete 100 ml where the organic coloring compound ionizes in aqueous medium and presents at least two structural forms with different colors depending on the pH changing in the pH range between 3 and 8, the acidity regulator is a weak acid that has at least a pKa with a value between 2 and 2.4, the solvent is selected from the group of water, toluene, acetone, isopropyl alcohol or a mixture of at least two hydrocarbons from the group of 2-butoxyethyl acetate, butyl glycol acetate or N-methyl-2-pyrrolidone.

[0066] This composition changes color in the presence of gamma-hydroxybutyrate (GHB), so the color change can serve as an indicator of the presence of this compound when added to a liquid containing it or when a sample of that liquid is added to the composition.

[0067] Although the compound can be used on its own, its design allows it to be used as screen printing ink, for printing on any surface that can be printed on with water-based screen printing ink. Therefore, it can be used to prepare a device for detecting the presence of GHB in an aqueous solution, such as a beverage intended for human consumption.

[0068] Thus, a second aspect of the present invention is a device for detecting GHB in an aqueous solution (preferably a beverage) comprising at least one solid support comprising a surface with a detection area, characterized in that the detection area comprises the composition of the present invention bonded thereto.

[0069] Since, according to the present invention, the deposition of the composition of the invention on the support is carried out by the screen printing technique, using the composition of the present invention as screen printing ink, the composition of the present invention is referred to in some passages of the present application as the screen printing ink or also, due to the ability to change color in the presence of GHB, it is also referred to as the reactive ink.

[0070] The presence of water-based screen printing ink in the composition of the present invention, and its application to the device's substrate using screen printing techniques, does not prevent the organic coloring compound from changing color if the pH is altered. Thus, by placing one or two drops of the liquid solution in which the presence of GHB is to be tested onto the detection surface, if the compound is present, a color change will occur, clearly indicating its presence in the liquid being tested (for example, a beverage). However, when tested with liquids that do not contain this substance, such as water or unadulterated beverages, the device's detection area (or the composition itself) maintains its original color, ensuring high specificity and the absence of false positives.

[0071] The color change occurs due to the transformation of the structural form of the indicator, stable at the initial, more acidic pH of the composition (which is usually a non-ionized form of the coloring compound), into the structural form stable at a less acidic pH (which is usually an ionized form that has lost a proton, H₂). +(with respect to the most stable structural form at the most acidic pH from which it originates); the different color of each of these structural forms will result in a color change of the composition of the invention, which acts as an indicator for detecting the presence of GHB. As specified below, the color-changing compound can be a pH indicator from the group traditionally used in acid-base titrations and as pH indicators in aqueous solutions where a specific range needs to be identified. These compounds have been traditionally used because the color change is clear and sharp within their transition range, facilitating their practical use in visual analyses. Furthermore, they are generally soluble in water or alcohol, which facilitates their application in liquid media, operating in close pH ranges, generally between pH 3 and 6.

[0072] Preferably, the substrate is a strong, lightweight, and waterproof material that does not absorb ink. More preferably, the substrate is a polymeric material of the nonwoven fabric type. Although the polymeric material can be rigid and accommodate different detection device formats, a flexible material is especially preferred, such as a polymeric material composed of randomly arranged and compressed ("spunbound") high-density polyethylene fibers, like Tyvek®, marketed by DuPont® and commercially available from the company itself (https: / / www.dupont.es / brands / tyvek.html) or from suppliers such as DURA-ID Solutions (Shirebrook, Great Britain). This material allows the device to be prepared in different formats, particularly as strips whose ends can be glued together to form a wristband.Using a waterproof and durable support is an advantage over devices based on supports such as cardboard or paper, which can be easily affected by spills of drinks or other liquids on them, or even by rainwater at outdoor events, which can complicate their use in places where the addition of GHB to drinks is more common.

[0073] The components of the composition of the present invention, as well as their concentration, have been carefully chosen so that, on the one hand, the composition of the present invention is printable on the aforementioned supports, a property that had not been described for other compositions of the prior art designed to form part of GHB detection devices in aqueous solutions such as beverages.Furthermore, the composition is also designed so that the devices of the invention on which it is printed can indicate the presence of GBH in the solution deposited on the detection area (area to which the composition of the present invention is attached) in a clear, fast, simple, specific manner and with a detection limit (20 mM of GHB), suitable for the concentrations that are usually added to drinks in leisure places with the intention of drugging the person consuming the drink and which is below the minimum concentration necessary in the drink to have an effect on the body.

[0074] In particular, the combination of the acidity regulator (a weak acid with a pKa between 2 and 2.4) and the colorant (an organic compound with a pKa of 5 ± 2) is optimal, both in terms of the selection of the possible weak acids that can be part of the composition and their concentration range (the specific amounts to add to prepare the composition of the invention), as well as their ability to regulate the pH under the color change conditions of the chosen colorants. The weak acids compatible with the present invention regulate the pH without preventing the color change of the colorant from occurring if GHB is present in the aqueous solution (e.g., a beverage) being tested, thus avoiding the potential false positives that occur with some current devices.

[0075] Furthermore, the composition of water-based screen printing inks is suitable for inclusion in the compositions of the present invention and for applying said composition in GHB detection devices, because they do not react with the pH regulator or the dye and do not prevent them from performing their function, making them suitable for the compositions of the present invention, unlike what would happen, for example, with inks used for other types of printing, such as inks commonly called "printer" or "drum" inks (because it is the electrically charged rotating roller that allows images to be drawn by rotating on its own axis when it receives the laser impacts), which contain, in addition to the color pigment, anti-caking agents, resins and the developer agent and which would not be compatible with the use of the composition of the present invention for GHB detection.

[0076] Furthermore, screen printing ensures that the composition of the present invention adheres to the surface of the substrate, making it easily accessible to the aqueous solution (e.g., beverage) applied to it. This facilitates interaction with its components, including any GHB that may be present. This not only facilitates a rapid reaction but also eliminates the need for highly porous substrates, as is the case with vaporizers in existing devices. It also simplifies the preparation of the devices, which, in its simplest embodiments, involves preparing the composition of the invention and printing it onto the substrate. Preferably, an adhesive substance is also added to one end in the embodiment intended for use as a wristband.The method is not only simple, but easily adaptable to large-scale industrial preparation, and uses a very common technique such as screen printing, which is an advantage over several currently known devices, such as the colorimetric sensor of Son et al. cited above, which operates in a short detection time, but requires electrospinning techniques for its preparation. Thus, a method for preparing a device for the detection of GHB in aqueous solutions, such as beverages, such as the devices of the present invention, is also an aspect of the present invention.

[0077] Thus, surprisingly, although the compositions of the present invention and the detection devices on which they are printed base the detection of GHB on a color change of a coloring compound (pigment) due to pH variations that result in the deprotonation of the form of the dye present in the composition before the addition of GHB, in a manner analogous to what occurs in some commercial devices and / or in several devices described in patent documents (see, for example, the content of application W02003021254), and although the preferred dyes in the present invention are also pH indicators selected from the group of those traditionally used for titrations of solutions according to the color of the indicator compound, the combination of components of the compositions of the present invention, each in the specific concentration ranges for each of them,as well as its bonding to the surface of the substrate as if it were a printing ink, resulting in faster detection, improving specificity and decreasing the risk of false positives, while still maintaining an adequate detection threshold.

[0078] The approach of the present invention is quite different and not at all obvious from the knowledge disclosed in application US2022'35739, which is directed at the identification and detection of drugs of abuse such as the alkaloids nicotine and cocaine, but in different samples: residues remaining on vape pen surfaces and in oily / viscous vaping liquid formulations. The present invention, on the other hand, is directed at the detection of GHB in beverages for human consumption, which are complex aqueous matrices that may contain alcohol, sugar, and gas, and which have a variable pH. The reactive compositions of application US2022'35739 can also be used for printing substrates and include a colorimetric agent whose color change range may coincide with that of the organic dyes of the present invention, and a catalytic agent that is an acid, which may coincide with a suitable acidity regulator for the present invention, such as citric acid.However, the ratios between the two compounds in the corresponding compositions are different, with the amount of catalytic agent being considerably higher in that application. This is related to the different function the acid performs in each of the inventions: while in application US2022'35739 it is a catalytic reagent, increasing the rate of color change, in the present invention it does not have that function. Instead, it is present to adjust and buffer the pH of the detection zone, placing it just below the indicator's endpoint, which is crucial to avoid false positives in basic beverages.Furthermore, a detailed analysis reveals technical incompatibilities between the two compositions: while the liquid compositions of application US2022'35739, designed for printing on substrates, contain an alcoholic solvent (specifically methanol in the Examples), and in large proportions (2-2.5 liters per 6-9 grams of colorimetric agent) to form a reactive ink (a formulation suitable for dissolving vaping oils), the present invention necessarily comprises a water-based screen printing ink, because the water base is critical for immediate miscibility with the beverage (water-based) to be tested and for creating a stable emulsion, suitable for drying and adhering to a surface, thus enabling industrial screen printing on the preferred substrates, which are waterproof, as discussed below, something that a methanol solution does not allow to be done directly without evaporating or shifting.Therefore, the compositions suitable for use as inks in application US2022'35739 and in the present invention are chemically different products with different behavior.

[0079] The choice of a waterproof substrate, in addition to using the composition of the present invention as screen printing ink to print the detection area of ​​the substrate with said reactive ink, avoids the problems presented by other substrates on the market not only with respect to the stability of the substrate itself against water and other aqueous solutions, as already mentioned, but also with respect to the stability of the reactive ink itself (the composition attached to the substrate in the detection area) in case the device gets wet.

[0080] Thus, it can be said that the present invention, and in particular the devices that form part of it, presents several significant advantages over existing methods with regard to the detection of GHB in aqueous solutions such as beverages, such as the following:

[0081] • Speed: The color change occurs in less than 2 seconds, providing immediate detection.

[0082] • Specificity: Responds exclusively to GHB, without interference from other common fluids.

[0083] • Ease of use: Requires no technical knowledge or additional devices.

[0084] • Simplicity: The result is obtained directly on the material in which the sample of the tested aqueous solution (drink) is deposited, without the need to use successive elements or to perform several different successive mixtures until the result is obtained.

[0085] • Portability: The device of the present invention allows for various formats, making it easy to carry to places where drinks will be consumed. In particular, the wristband format allows the sensor to be worn discreetly and accessibly in any environment. Thus, given the increasing number of cases of sexual assault under drug dependency, the present invention represents an alternative to meet the critical market need, both for consumers and for entities dedicated to safety in leisure activities, for simple and quick devices to detect the presence of GHB in drinks, especially those consumed in leisure and party venues such as raves and bars.

[0086] Therefore, another aspect of the present invention is the use of the compositions and / or devices of the present invention for the detection of GHB in aqueous solutions, particularly beverages for human consumption or even beverages for animal consumption.

[0087] The invention is now explained in more detail below.

[0088] Brief description of the figures

[0089] Fig. 1. Chemical formulas of gamma-hydroxybutyrate (GHB) (left) and its sodium salt (right).

[0090] Fig. 2. Schematic representation of an embodiment of the device of the invention in the form of a strip or band with adhesive ends that allows its use as a wristband. The device comprises a lower surface and an upper surface, intended to be the outer surface of the wristband. The upper surface contains at least: an area at one end containing an adhesive (represented in the drawing by the word "glue"), which allows the upper surface of the opposite end of the strip to be adhered to said area, to form a wristband; and a detection area (represented by the shaded square), preferably located in the central area or away from the ends, impregnated with the composition of the invention (represented in the drawing by the shading itself and the word "ink") comprising the compound that indicates the presence of GHB by a change in its color.Preferably, the surface also includes an information area, which may be adjacent to the detection area, explaining whether or not the beverage contains GHB based on the color visible in the test area after the test is performed. Optionally, the strip also includes an additional area where optional content, such as printed material or stickers, may be inserted, which may display one or more company logos and / or decorative motifs. Detailed description of the invention. Possible embodiments.

[0091] As previously stated, the present invention relates to a composition that can be used as ink for printing materials by screen printing and that allows the detection of the presence of GHB in aqueous solutions, such as beverages, by means of a color change easily visible to the naked eye, as well as to devices for the detection of GHB that are based on said composition, which forms part of the devices by virtue of the reactive composition being printed, in the manner of screen printing ink, on the surface of a support that is also part of the device, the presence or absence of GHB being detected by depositing a sample of the liquid to be tested (one or two drops) on the surface to which the reactive composition is attached (the detection area) and observing whether, after a short waiting period (a few seconds are sufficient), a color change is observed in the detection area, which indicates, respectively,the presence or absence of GHB in the tested solution.

[0092] The detection of GHB using the composition and device of the invention can be carried out quickly, clearly, reliably, specifically, and easily thanks to the combination of ingredients of the composition of the invention, in the appropriate quantities, and the characteristics of the detection device. This device comprises said compositions printed on the surface of a substrate using screen printing techniques, which are possible because the composition, in addition to detecting GHB, can be used as a screen printing ink. Therefore, the method of preparing the devices of the invention and the use of the composition of the invention or the devices of the invention to detect the presence of GHB in liquid solutions, such as beverages, are also aspects of the invention. These beverages are commonly consumed in leisure establishments where, on occasion, GHB is added to drinks to impair the will of those who consume them.

[0093] The main ingredients comprising the compositions of the invention have the following characteristics:

[0094] - Water-based screen printing ink: This provides the matrix for the reagents. All of them contain water and generally also binders (acrylic resins or polyurethane, to facilitate adhesion to the substrate) and additives such as wetting agents, retarders, and viscosity regulators. They can be used for printing on a wide variety of substrates, including woven fabrics, but also non-woven textiles (NWT). Within this category, two main groups can be distinguished: those containing lacquers and those containing acramines. Lacquers give the inks a whitish (opaque) base, to which the desired pigment is applied to achieve a color, while acramines result in transparent inks.

[0095] In the compositions of the present invention, both lacquer-based and acramine-based inks may be used, and any brand and format may be used, provided they remain water-based and are colorless or white so that, when the color indicator pigment is added, it does not interfere with any pre-existing color. Although compositions of the invention used without being bonded to a substrate are preferably transparent, in compositions of the invention intended for preparing devices of the present invention, it is preferable that the water-based sign-printing inks of the invention be opaque and matte, preferably white. In particular, water-based vinyl-acrylic (vinyl copolymer) inks may be used, such as the one used in the devices of the Examples of this application (the VINYLMAT® product, from the Engler Srl trademark).(Casnate con Bernate, Como, Italy) and distributed by Artic SA (https: / / www.articsa.net / es / producto / vinylmat / )), which consists of a vinyl-acrylic (vinyl copolymer) based printing ink with excellent printing properties and opacity. It is designed for printing on plastic materials and performs optimally in mechanical tests such as sample bending, twisting, and stretching.

[0096] - Organic coloring compound (color indicator): These are organic compounds that have at least two structural forms with different colors depending on the pH. For the present invention, the use of acid-base indicator compounds that ionize in aqueous medium is preferred, in which the formation of one or the other structural form occurs by protonation / deprotonation, with the more protonated form (e.g., non-ionized or monoanionic, having already lost a proton) being the most prevalent structural form at more acidic pHs, while the less protonated form (e.g.The monoanionic form (if the other form was not ionized) or the dianionic form (if the other form was monoanionic) is predominant at less acidic and more alkaline pH values, with the concentration of both forms being the same at a pH value called pKa. It is also possible to use weak bases, which are compounds in which the non-ionized form is predominant at more acidic pH values ​​(lower than the pKa), while the ionized form is a protonated monocationic form that predominates at pH values ​​higher than the pKa, provided that each of these structural forms has a different color, or even that one of them is colored and the other is colorless. Some indicators have several pKa values ​​and exhibit different color changes in the ranges close to each of these pKa values.Specifically, among these compounds, those traditionally used primarily in acid-base titrations and as pH indicators in aqueous solutions are preferred, where a specific range needs to be identified, since the color change is clear and sharp within their transition range (a transition range that is usually, for the human eye, between one pH unit below the pKa and one pH unit above the pKa), which facilitates their practical use in visual analyses; in addition, they are generally soluble in water or alcohol, which facilitates their application in liquid media, operating in pH ranges close to the pKa. (Lurie, 1975).For the purposes of the present invention, indicators that have a pKa of 5 ± 2 and / or that have a color change range between pH 3 and pH 8 are preferred, that is, if the medium is acidified, it becomes apparent to the naked eye that the major form at a more acidic pH, the most protonated form, begins to convert into the deprotonated form (the form that contains an H). + that the form from which it is derived) at a pH value of 3 or higher, whereas, if the medium is acidified, it can be seen with the naked eye that the deprotonated form begins to protonate at a pH value of 8 or lower.

[0097] Special preference is given to organic coloring compounds with a transition range between pH 3.5 and 6.5, which is particularly suitable for the purposes of the invention due to the chemical nature of the matrices to be analyzed (consumer beverages): As discussed in the previous paragraph, it is important that the transition of the organic coloring does not begin at a pH lower than 3.0 - 3.5, because many commercial beverages (cola soft drinks, energy drinks, wines) have their own acidic pH that ranges between 2.5 and 3.5 and, if a coloring with too low a pKa were used, the acidity of the beverage itself would cause the color change without the presence of GHB, generating a false positive.On the other hand, since GHB acts as a weak base, the pH increase it generates in the buffered sample is moderate. Therefore, an organic dye requiring a pH above 7 or 8 to change color might not be sensitive enough, resulting in a false negative. Thus, the most suitable organic dyes are those whose transition range lies entirely or mostly within these limits.For the purposes of the present invention, the organic coloring compound may be selected from the group of methyl orange (color change range of pH 3.1 - 4.4, changing from red to orange), methyl red (color change from red (pH 4.2) to yellow (pH 6.2), with orange hues in the color change range of pH 4.4-6.2), chlorophenol red (color change from yellow (pH 4.8) to violet (pH 6.7)), bromocresol green (color change from yellow (pH 3.8) to blue-green (pH 5.4)), bromophenol blue (color change range of pH 3 to pH 4.6, changing from yellow to blue-violet-purple), bromocresol red, bromophenol red (color change from yellow (pH 5.0) to red (pH 6.8)), o-nitrophenol (color change of colorless (pH 5.0) to yellow (pH 7.0)), bromocresol violet (change from yellow (pH 5.2) to violet (pH 6.8)), nitrozine yellow (change from yellow (pH 6.0) to blue-violet (pH 7.0)), p-nitrophenol (change from colorless (pH 5.6) to yellow (pH 7.6)) and bromothymol blue (change from yellow (pH 6.0) to blue (pH 7.6)). Before coming into contact with the solution (e.g., beverage) to be tested, the organic dye will be in the color corresponding to the major structural form at the lowest pH; upon contact with the aqueous solution to be tested, the color will remain the same if there is no GHB in the sample, while there will be a color change towards the major form at a higher pH (more basic pH) if there is GHB in the sample.

[0098] Of the organic coloring compounds in the list above, special preference is given to those with a transition range approximately within the interval of 3.5 - 6.5, and more specifically to:

[0099] - Bromocresol green (approximate transition range: pH 3.8 - 5.4)

[0100] - Bromophenol blue (approximate transition range: pH 3.0 - 4.6)

[0101] - Methyl red (approximate transition range: pH 4.4 - 6.2)

[0102] - Bromocresol red (approximate transition range: pH 5.2 - 6.8)

[0103] - Chlorophenol red (approximate transition range: pH 4.8 - 6.4)

[0104] The use of bromocresol green is particularly preferred because its color change range perfectly matches the detection advantage of GHB. The color change indicating the presence of GHB is clear and easily noticeable, occurring within a range of easily distinguishable colors under the low-light conditions often found in bars and nightclubs where drinks are consumed and where GHB is frequently added. In aqueous solution, it ionizes to form the monoanionic (yellow) form, which deprotonates as the pH increases to form the dianionic (blue) form, which is stabilized by resonance. Thus, in this particular case, the composition of the invention (and, consequently, the detection zone of the device to which the composition will be attached, if such a device is used) will initially exhibit a yellow-orange color.Upon contact with the aqueous solution to be tested, in the absence of GHB there will be no change in color, while in the presence of GHB a change towards green will be observed, indicating the presence of said compound in the liquid analyzed, making it inadvisable to continue consuming it if the liquid is a beverage.

[0105] - Acidity regulator: Acts as a pH modifier to ensure sensor specificity. For the purposes of the invention, it is a weak acid with a pKa between 2 and 2.4. The acid lowers the pH of the mixture, thus modifying the indicator's sensitivity range and rendering it unreactive to liquids slightly more alkaline than commercial beverages (such as soft drinks, beer, etc.), such as tap water (due to the presence of carbonates). The addition of this compound decreases the transition range of the composition containing, for example, bromocresol green, from 3.8–5.4 to 3.8–4.3, eliminating interference from tap water, which typically has a pH around 5–6 in hard water regions. If the water is softer, i.e., contains fewer dissolved carbonates, the interference is not considered.For the present invention, the acidity regulator may be selected from the group of tartaric acid, citric acid, phosphoric acid, citraconic acid, and lactic acid. Citric acid is preferred.

[0106] - Solvent: This may not be necessary if the added components already provide the desired volume. It facilitates the homogeneous integration of the components and ensures a specific density and viscosity for the printing process. It can be selected from the following groups: water, toluene, acetone, isopropyl alcohol, or a mixture of at least two hydrocarbons that are part of the group of solvents commonly used in industry, such as 2-butoxyethyl acetate, butyl glycol acetate, or N-methyl-2-pyrrolidone, for example, a mixture of 2-butoxyethyl acetate / butyl glycol acetate in a 1.5:1 ratio.

[0107] Particular preference is given to the embodiment of the composition of the present invention used in Examples 2-3 of this application, namely, the composition comprising, per 100 ml: 50-97.5 ml white, opaque, water-based screen printing ink; 2.5-10 g bromocresol green; 2.5-8.75 g citric acid; solvent to make up to 100 ml, wherein the solvent is a mixture of 2-butoxyethyl acetate / butyl glycol acetate in a 1.5 / 1 ratio; and wherein, preferably, the white, opaque, water-based screen printing ink comprises vinyl copolymers.

[0108] Also preferred embodiments of the composition of the present invention are those used in Examples 4 and 5, namely: both a composition comprising, per 100 ml opaque white water-based screen printing ink, 92 ml bromocresol green, 5 g tartaric acid, 6 g solvent, if necessary to complete the volume: a mixture of 2-butoxyethyl acetate / butyl glycol acetate in a 1.5 / 1 ratio to complete 100 ml, and wherein, preferably, the opaque white water-based screen printing ink comprises vinyl copolymers; as well as a composition comprising, per 100 ml of opaque white water-based screen printing ink, 92 ml of methyl red, 4 g of citric acid, 3.5 g of solvent, if necessary to complete the volume: a mixture of 2-butoxyethyl acetate / butyl glycol acetate in a 1.5 / 1 ratio to complete 100 ml, and where, preferably, the opaque white water-based screen printing ink comprises vinyl copolymers.

[0109] As previously mentioned, the composition of the present invention can be used as screen printing ink for printing materials. Furthermore, it is a reactive composition that allows the identification of the presence or absence of GHB in a liquid solution by a color change in the organic coloring compound (the indicator) or, in the absence of GHB, by the absence of a color change. Therefore, it can be used to prepare devices for detecting GHB in aqueous solutions, such as beverages, particularly beverages intended for human consumption, where the composition of the present invention can be used as screen printing ink, deposited onto the surface of a substrate in a screen-printing manner.

[0110] The devices comprising the composition of the present invention, as well as the procedure for preparing them by screen printing the composition, are also aspects of the present invention.

[0111] The device according to the present invention for detecting the presence of gamma-hydroxybutyric acid (GHB) in a sample is a device comprising: a) a support with an upper surface and a lower surface, and b) at least one detection zone on the upper surface on which the composition of the present invention is printed,

[0112] Water-based screen printing inks can be used to print on many different materials, including fabrics, paper, cardboard, or various polymeric materials such as PVC (either in its rigid or more flexible forms), polystyrene, polycarbonate, polypropylene, or polyester. Therefore, in its most basic form, the device of the present invention could be composed of any one of these printable supports with water-based screen printing inks (for example, cardboard shaped and sized like coasters or paper in various shapes, such as strips), with a surface having a detection zone where the composition of the present invention is printed.

[0113] However, it is preferred that the support be made of a resistant, lightweight and waterproof material, ideal for leisure environments, with the waterproof material being particularly preferred.

[0114] Among the wide range of printable substrates, there is a particular preference for polymeric materials known as non-woven fabrics (NWF). These textiles are produced by bonding polymer fibers through a mechanical or chemical process without weaving, resulting in a fabric composed of thousands of interconnected fibers. These materials offer ideal characteristics for this type of sensor (the detection device), such as resistance, impermeability, and lightness. Specifically, non-porous materials are preferred so that they do not absorb the ink, allowing it to adhere to the surface.An example of this type of material that can be used as a support in a particularly preferred embodiment of the present invention would be the composite material of randomly placed and compressed (“spunbound”) high-density polyethylene fibers, such as that of the Tyvek® brand, marketed by DuPont®.

[0115] This material, in addition to being waterproof, lightweight, resistant and non-porous to water-based screen printing ink, is also flexible, which facilitates preparing the device according to a preferred embodiment of the invention, in which the support is in the form of strips or bands of a length greater than the perimeter of an adult human's wrist, but less than the average perimeter of an adult human's hand, such as a length of 25 cm.In this way, by attaching an adhesive compound to one end of the strip or band, which is also attached to the support on the upper surface, the ends of the strip can be glued around a person's arm or wrist, forming a bracelet. In this bracelet, the upper surface of the support will be facing outwards, with the detection area easily accessible to perform the test for the presence or absence of GHB in a sample such as a drink, while the lower surface of the strip or band will face the person's skin, surrounding their wrist.

[0116] Ideally, the width of the strip or band should allow the user to easily place a few drops (one or two) of the aqueous solution to be tested onto the detection area and observe what happens to the area, checking whether or not a color change occurs. Ideally, the strip or band should be at least 0.5 cm wide, but preferably 2-3 cm, similar to the bands sold by various companies (for example, www.imprentaonline.net) for use as a wristband, which typically features decorative and / or identifying elements.

[0117] Figure 2 shows a possible embodiment of the device of the present invention in the form of a strip or band, in which the detection or testing area is located near the center of the strip, or at least preferably away from the ends that will be joined to form a wristband. In this embodiment, the strip also includes an information area explaining how to determine whether the tested liquid solution contains GHB based on the color that appears in the detection area after one or two drops of the liquid solution have been placed therein. Furthermore, in the specific embodiment shown, the strip also comprises an additional area where optional content, such as printed material or stickers, can be inserted, which may display one or more company logos and / or decorative motifs.

[0118] Although the strip or band format with adhesive ends is preferred due to its portability, ease of use and even the possibilities of maintaining discretion, embodiments of the device of the invention in which the support has other different shapes, for example rectangular or circular, are also compatible with the present invention and embodiments of the device of the invention are also possible.Possible embodiments also include those in which the substrate is bonded to an upper and a lower layer of any material, such as cardboard, such that the upper layer rests on the upper surface of the substrate and contains an opening that exposes the detection area to the outside, allowing for the placement of a few drops of the aqueous solution (such as a beverage) in which the presence of GHB is to be tested. Similar embodiments exist in which the substrate is covered by a protective casing, such as one made of a polymeric material, which also has an opening that exposes the detection area to the outside. Other possible embodiments of the device include test strips, with a substrate of paper or any other material printable by screen printing with water-based ink, in which the test can also be performed by immersing the strip in the aqueous solution to be tested.In fact, any support or device containing the composition of the present invention, whether attached to it or with the composition in liquid form in a container or receptacle, falls within the scope of the present invention.

[0119] Whatever the format, it is preferable that the device contains an information area similar to that shown in the device in Fig. 2, either printed on the support itself or on the casing or top layer that protects it, in which the user is informed how to interpret the result of the test: absence of GHB when there is no color change or the color change that will indicate the presence of GHB in the tested aqueous solution.

[0120] Regardless of the device's configuration and the specific materials used in its preparation, devices are preferred in which the composition of the detection zone is one of the preferred compositions of the invention detailed above and used in one of the Examples of this application. Among these, the composition comprising bromocresol green and citric acid is particularly preferred.All embodiments of the device of the invention are combinable with these preferences regarding the compositions, a highly preferred embodiment of the device of the invention being that which combines the preferred compositions in the detection area with the remaining preferences expressed above: support of waterproof material of non-porous non-woven fabric type preferably of high-density polyethylene fibers randomly placed and compressed (such as Tyvek®) in the form of a band with an area at one end to which an adhesive compound or material is attached (which allows the device to be shaped into a wristband for use) and with an information area in which it is explained how to identify the presence of GHB in the aqueous solution being tested.

[0121] As can be deduced from the preceding explanation, the use of the composition of the present invention or the device of the present invention to detect the presence of GHB in an aqueous solution is also an embodiment of the present invention. This aqueous solution is preferably a beverage intended for human consumption, but it can also be, among other things, a biological sample such as saliva.

[0122] To use one of the devices of the invention, simply place a few drops (one or two are sufficient, unless the device's detection area is very large and a larger sample size is needed) of the aqueous solution to be tested onto the device's detection area and wait a few minutes to see if a color change occurs. The expected color change (from the predominant form of the dye at acidic pH to the predominant form of the dye at a pH higher than the indicator's pKa, as explained above), which will occur within seconds, will indicate the presence of GHB. Therefore, if the tested solution is a beverage, it will have been doped with GHB, and the consumer should stop drinking it.

[0123] The sample can be obtained simply by dipping a finger into the solution to be tested and placing one or two drops onto the device's detection area. The device may also be sold with a dropper for taking a sample of the aqueous solution to be tested, for those who prefer not to dip their finger into the beverage.

[0124] As can be seen in the Examples section of this application, the devices of the present invention allow the detection of the presence of GHB in various types of beverages, both in non-alcoholic soft drinks, even if they have different colors (cola soft drinks, soft drinks with orange or lemon flavor or even energy drinks), as well as in beers (with or without alcohol), in white or red wine or in high alcohol content beverages (generally greater than 25 degrees alcoholic, often between 30 and 60 degrees alcoholic, that is, containing more than 25 milliliters of alcohol (understood as the compound known as ethyl alcohol or ethanol) per 100 milliliters of beverage) such as the beverages grouped under the names of spirits or spirit drinks such as whiskey, rum, gin, vodka or tequila.The use of the compositions of the present invention or of the devices of the present invention to detect the presence of GHB in any of these beverages falls within the scope of the present invention.

[0125] When tested with liquids that do not contain this substance, such as water or unadulterated beverages, the detection area maintains its original color, guaranteeing high specificity and absence of false positives.

[0126] As previously discussed, obtaining compositions that can be used to detect the presence of GHB in aqueous solutions by color change and that, at the same time, can be used as water-based screen printing inks had not been previously described and offers the possibility of preparing GHB detection devices by printing the reactive composition on a support by screen printing methods.

[0127] Thus, a procedure for preparing a device of the present invention, according to any of the possible embodiments previously described in this document for the same, in which the composition of the present invention is printed on a support by means of the screen printing technique, is part of the invention.

[0128] The procedure of the present invention can be defined as a procedure for preparing a GHB detection device comprising the steps of: a) obtaining a composition of the present invention, according to any of the possible embodiments described in this document for the same, b) printing said composition on a support by screen printing.

[0129] The manufacturing process will vary depending on the material used to manufacture the printing substrate. Obtaining the substrate can be considered an additional step in the invention's process, prior to printing. The substrate may have any of the characteristics previously described herein, compatible with the devices of the present invention. Depending on the substrate and its desired format, obtaining it may simply involve purchasing it commercially or may require some adaptation.

[0130] When the support used is the preferred support in the present invention, a non-woven polymeric material, more preferably specifically the material of randomly placed and compressed high-density polyethylene fibers such as the commercial product with the name Tyvek®, the material can be purchased already in the form of bands with which to prepare adjustable wristbands, guaranteeing the mechanical resistance and impermeability of the support; the bands can be purchased already with an adhesive area at one end, which can function as a closure, guaranteeing its position and accessibility throughout the period of use, as previously discussed.

[0131] If the material is not already in the desired format, such as the strip used to make wristbands, a similar system can be created by cutting the material into the desired shape (strips, bands, rectangular or circular surfaces, or any other desired shape). If the desired format of bands for making wristbands is used, an adhesive of any type can be applied to one end of the band, on the same surface where the reactive ink will be printed. The adhesive will not come into contact with the reactive ink and therefore will not interfere with its composition.

[0132] As already mentioned, the support can be made of various materials, such as polypropylene or polyester, although other starting materials such as polyamide or viscose fibers or any combination of these can also be used.

[0133] For the preparation of the composition (which will be the reactive ink), the preparation stage can be considered to include the following steps:

[0134] - mix, in the desired proportions, the components of the composition: the water-based sign-printing ink, the organic coloring compound and the acidity regulator,

[0135] - fill to the desired volume with the chosen solvent,

[0136] - Homogenize the mixture until a stable and uniform solution is achieved.

[0137] The components are preferably mixed, according to the optimal mixing order, which consists of adding the solid compounds (indicator and acidity regulator) to the liquid (water-based ink) and finally the solvent until the desired consistency and volume are achieved.

[0138] In a possible preferred embodiment, for optimal operation of the device, the preferred embodiment of the composition of the present invention used in Examples 2-3 of this application may be prepared, i.e., the composition preparation step may result in the composition comprising, for the preparation of 100 ml of reactive ink:

[0139] • White, opaque, water-based screen printing ink base: 50 - 97.5 ml

[0140] • Color indicator: bromocresol green: 2.5 - 10 g (2,500 - 10,000 mg)

[0141] • Weak acid: citric acid: 2.5 - 8.75 g (2500 - 8750 mg)

[0142] • Solvent, if necessary, to make up to 100 ml, where the solvent is a mixture of 2-butoxyethyl acetate / butyl glycol acetate in a ratio of 1.5 / 1.

[0143] The screen printing process, for its part, consists of several stages that will result in the application of a uniform layer of ink onto the chosen substrate. The steps or sub-stages included in screen printing on the substrate are: i. Mesh Preparation.

[0144] The mesh, which contains the design to be printed, is attached to a frame to keep it taut. This mesh is pre-coated with a photosensitive emulsion. The original design is placed in contact with the mesh and exposed to light, hardening the areas not covered by the design. It is then washed with water, removing the unhardened emulsion and leaving the areas where the ink will pass through.

[0145] i. Assembly on the Sign Printing Equipment

[0146] The frame is placed on a support, such as a screen printing press or a linear table, which includes a system for correctly aligning the support on which the composition acting as screen printing ink will be printed. iii. Application of the Reactive Ink (the composition of the present invention)

[0147] The sign printing ink (the composition of the present invention used as sign printing ink) is deposited on the top of the mesh, without directly touching the design. A squeegee, usually made of rubber, applies moderate pressure to spread the ink evenly over the mesh. iv. Transferring the Design to the Device Support

[0148] The composition used as sign-printing ink passes through the open areas of the mesh (the design) and is deposited directly onto the surface of the device being prepared. v. Drying and Fixing

[0149] In the case of reactive inks, printing may require heat treatment to activate the reaction and fix the ink to the material. This ensures wear resistance and a high-quality finish. The heat treatment can take place, for example, in an oven at a temperature not exceeding 50°C. e C (40 e C - 50 eC, preferably for a period not exceeding 30 seconds) or even by applying an air current, preferably from above. This drying stage may result in the evaporation of some of the solvent. Therefore, when referring to the “composition of the present invention,” alluding to its presence in devices of the present invention, printed on suitable substrates compatible with the invention, it should be understood that there may be a difference in the initial solvent content used and the portion of the solvent bound to the detection area. However, since the quantity of said solvent is not strictly fixed in the definition of the compositions of the invention, it should be understood that this difference does not preclude referring to the compositions affixed to the devices and defining them as compositions of the present invention. vi. Final Finish

[0150] Once the fixing is done, the support is inspected to ensure the quality of the print.

[0151] The detection zone can have different shapes, so the original design can vary as desired.

[0152] This process can be repeated to apply multiple colors if the design requires it, especially if the device's substrate contains additional printed elements beyond the detection area. This could include an information area explaining how to interpret the results based on the final color of the detection area after the GHB detection test, or additional printed information such as company logos or decorations. This method is versatile and applicable to various materials thanks to the ability of reactive inks to adhere to and chemically react with polymers and other substrates. The resulting printed substrate exhibits high-quality, durable printing.

[0153] A preferred embodiment of the invention is one in which the support is of the preferred material and shape, i.e., one in which the support is a band of randomly placed and compressed high-density polyethylene fibers, particularly the commercial product Tyvek®.

[0154] In the case of devices comprising additional materials, such as those in which the support is protected by an upper and lower layer of another material or inserted into a housing, the procedure shall comprise an additional step in which the complete device is formed.

[0155] The proper functioning of the compositions of the invention and of the devices in which they are present is demonstrated by the Examples set out below.

[0156] Examples

[0157] Evaluation of the correct use of the sensor (device of the invention)

[0158] The sensor (device of the invention) manufactured as described above has been subjected to rigorous testing to evaluate its effectiveness and reliability. Specifically, a strip-shaped device prepared using Tyvek® as a substrate was used, with the preferred composition of the invention comprising citric acid, bromocresol green, and the previously mentioned preferred commercial ink, VINYLMAT®, following the printing procedure described in the preceding section. In Example 1, tests were performed to identify suitable concentration ranges for each of the components. In Examples 2 and 3, the preferred embodiment of the composition of the present invention was used, in which the added ingredients were specifically: ink: 90-99 ml; bromocresol green: 7 g; citric acid: 4-7 g, with the volume made up to 1.5:1 with 2-butoxyethyl acetate / butyl glycol acetate. Example 1.

[0159] Tests were conducted to determine the optimal operating concentrations of the mixture, verifying the different composition parameters. For this purpose, undiluted VINYLMAT® Bianco Extra white ink base (Engler Italia SrL, 201212) was used, which generates a thicker reactive layer in the detection zone.

[0160] Regarding the indicator, it was found that quantities below 2.5 g per 100 ml resulted in a color that was too faint to clearly show the result. Furthermore, product values ​​above the upper limit of 10 g per 100 ml complicated the homogenization process, causing lumps to appear in the mixture. It functions properly within the range of 2.5 to 10 g per 100 ml.

[0161] Regarding the amount of acid, the minimum concentration for citric acid was set at 25 mg / ml to avoid nonspecific reactions with liquids with a pH greater than 4.5-5. Exceeding the maximum amount (10 g per 100 ml) also disables the ink's reactivity, preventing it from responding to the presence of GHB in beverages. It functions properly within the range of 2.5-8.75 g per 100 ml.

[0162] The amount of solvent to be used will vary depending on the desired consistency and density of the ink, which will vary according to the surface to be printed and the amount of ink to be deposited. For the Examples and part of the preferred composition of the invention, 2-butoxyethyl acetate / butyl glycol acetate in a 1.5 / 1 ratio was chosen as the solvent.

[0163] It was also verified that the optimal order for mixing the components is the addition of the solid compounds (indicator and acidity regulator) to the liquid (water-based ink) and finally the solvent until the desired consistency is achieved.

[0164] Example 2. Tests on adulterated beverages

[0165] Tests were conducted on liquids such as cola soft drinks (Coca-Cola®), orange-flavored drinks (Fanta®), and energy drinks (Red Bull®), combined or not with spirits (Beefeater® gin, Negrita® rum, Cutty Sark® whisky, and Knebep® Blanc vodka, among others) mixed in a 1:3 ratio (one part alcohol to two parts soft drink) and spiked with GHB at concentrations of 90 mM, representative of levels used in real-life cases of drug-facilitated sexual assault. For the tests, a drop of each spiked beverage was placed onto the surface printed with the reactive ink using a pipette. Subsequently, its performance was also evaluated in a simulated real-world environment by applying the liquid directly to the detection area with a finger.

[0166] In addition, decreasing concentrations of GHB in the beverage were tested, establishing the detection limit at 20 mM GHB. The concentrations tested were: 90, 80, 70, 60, 50, 40, 30, 20, and 10 mM. This test was carried out in the same way as the previous one, by depositing, first with a pipette and then with a finger, a drop of the doped beverages onto the ink printed in the detection area.

[0167] In all cases, the sensor reacted with a quick and clear change of color (orange to green).

[0168] Example 3. Tests on unadulterated liquids

[0169] The sensor's performance (the detection device) was evaluated in tap water, soft drinks, and other common beverages. Specifically, the following were tested: o - Lemon soft drink: Fanta Lemon ® o - Orange soft drink: Fanta Orange ® o - Cola soft drink: Coca-Cola ® o - Energy drink: Red Bull ® in all possible combinations with spirits: o Gin: Beefeater® o Whisky: Cutty Sark® o Rum: Negrita® o Vodka: Knebep® White, as well as other beverages such as beer (with and without alcohol) and wine (white and red).

[0170] No color change was observed, confirming the absence of false positives.

[0171] The results confirm that the sensor (the device of the present invention), in particular the embodiment prepared with the reactive ink containing citric acid as an acidity regulator and bromocresol green as an organic dye (indicator) whose color change indicates the presence of GHB, is reliable, without false positives or negatives, and detects GHB at physiologically relevant concentrations. These same properties were subsequently confirmed with another dye and another acidity regulator.

[0172] Example 4. Alternative formulation with tartaric acid and evaluation in highly colored beverages (such as red wine and Coca-Cola®)

[0173] With the aim of validating the concepts associated with the invention and its operation throughout its scope, a new formulation of the composition of the invention was prepared by replacing the preferred acidity regulator (citric acid) with tartaric acid, while maintaining bromocresol green as the organic coloring compound.

[0174] The composition prepared per 100 ml consisted of:

[0175] • Water-based screen printing ink (VINYLMAT®): 92 ml

[0176] • Bromocresol green: 5 g

[0177] • Tartaric acid: 6 g

[0178] • Solvent (2-butoxyethyl acetate / butyl acetate 1.5 / 1 mixture): to complete volume.

[0179] The screen printing was carried out on Tyvek® substrate following the described procedure. The resulting sensor device displayed a bright orange color in its resting state.

[0180] To evaluate the efficacy in liquids with strong inherent color, trials were conducted with "tinto de verano," a common mixture in leisure settings composed of red wine and carbonated lemon soda (1:1 ratio), doped with GHB at a concentration of 20 mM and 50 mM. This matrix is ​​particularly complex due to the acidity of the lemon soda and the dark, purplish color of the wine.

[0181] When a drop of the doped "tinto de verano" mixture was placed on the detection area, an immediate color change (t < 2 seconds) from light orange to a dark bluish-green was observed. Despite the reddish / dark color of the wine, the sensor's color change was clearly visible to the naked eye, unequivocally distinguishable from the control sample (tinto de verano without GHB), where the sensor retained its original orange color. This confirms that tartaric acid effectively acts as an acidity regulator, maintaining the local pH below the indicator's color change point even in acidic alcoholic mixtures.

[0182] Example 5. Evaluation of inks with alternative indicators: Methyl Red.

[0183] A test was carried out to verify the functioning of the invention using an organic dye compound other than those of the bromocresol series. Methyl Red (pKa ~ 5.1) was selected, whose color change range is between pH 4.4 (red) and pH 6.2 (yellow).

[0184] The prepared composition was as follows:

[0185] • Water-based screen printing ink (VINYLMAT®): 95 ml

[0186] • Methyl red: 4 g

[0187] • Citric acid: 3.5 g

[0188] • Solvent (2-butoxyethyl acetate / butyl acetate 1.5 / 1 mixture): to complete volume.

[0189] The device printed with this composition had an intense red / pink color when dry (acidic state).

[0190] Tests were conducted using cola (Coca-Cola®) doped with GHB (30 mM). When a drop of GHB-doped Coca-Cola® was applied to the red sensor, the presence of GHB caused deprotonation of the Methyl Red indicator, resulting in a visual shift to yellow-orange. Against the white background of the base ink, the change from red to yellow was distinguishable even with the dark concentration of the cola.

[0191] This example demonstrates that the invention allows the use of different chromogenic indicators by adjusting the formulation, making it functional even in dark carbonated beverages. References

[0192] Badcock NR and R. Zotti, “Rapid screening test for gamma-hydroxybutyric acid (GHB, fantasy) in urine,” Ther Drug Monit. 1999 Jun;21 (3):376 1999. doi: 10.1097 / 00007691 - 199906000-00023

[0193] Baumes L. A., M. B. Sogo, P. Montes-Navajas, A. Corma, and H. Garcia, “A colorimetric sensor array for the detection of the date-rape drug y-Hydroxybutyric acid (GHB): A supramolecular approach,” Chemistry, 2010 Apr 19;16(15):4489-95. doi: 10.1002 / chem.200903127

[0194] Beynon C.M., H. R. Sumnall, J. McVeigh, J. C. Cole, and M. A. Bellis, “The ability of two commercially available quick test kits to detect drug -facilitated sexual assault drugs in beverages,” Addiction, vol. 101 , no. 10, 2006, doi: 10.11 11 / j.1360-0443.2006.01420.x

[0195] Bravo D., D. Harris, and S. Parsons, “ Reliable, Sensitive, Rapid and Quantitative Enzyme-Based Assay for Gamma -Hydroxybutyric Acid (GHB) ,” J Forensic Sci, 2004 Mar;49(2):379-87. doi: 10.1520 / jfs2003165

[0196] Child A. M. and P. Child, “Ability of commercially available ‘date-rape’ drug test kits to detect gamma-hydroxybutyrate in popular drinks,” Canadian Society of Forensic Science Journal, vol. 40, no. 3, 2007, doi: 10.1080 / 00085030.2007.10757155

[0197] Hernández-Contreras J. et al., “Green and real-time detection of GHB in soft drinks and alcoholic beverages using an eco-friendly cellulose paper-based fluorescent probe,” Sens Biosensing Res, vol. 46: 100691 , Dec. 2024, doi: 10.1016 / j.sbsr.2O24.100691

[0198] Ingels A.S.M.E., S. M. R. Wille, N. Samyn, W. E. Lambert, and C. P. Stove, “Screening and confirmation methods for GHB determination in biological fluids Forensic Toxicology,” Anal Bioanal Chem. 2014 Jun;406(15):3553-77. doi: 10.1007 / s00216- 013-7586-6

[0199] LeBeau M. A., M. A. Montgomery, M. L. Miller, and S. G. Burmeister, “Analysis of biofluids for gamma-hydroxybutyrate (GHB) and gamma-butyrolactone (GBL) by headspace GC-FID and GC-MS,” J Anal Toxicol, 2000; 24: 421-428. doi: 10.1093 / jat / 24.6.421

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[0202] Rodríguez-Nuévalos S. et al., “Heteroditopic chemosensor to detect y-hydroxybutyric acid (GHB) in soft drinks and alcoholic beverages,” Analyst, vol 146, no. 18, 2021 , doi: 10.1039 / d1 an01084k

[0203] Son S. U. et al., “Colorimetric paper sensor for visual detection of date-rape drug y- hydroxybutyric acid (GHB),” Sens Actuators B Chem, vol. 347, 15 Nov 2021 , 130598, doi: 10.1016 / j.snb.2O21.130598

Claims

CLAIMS 1. An aqueous composition characterized in that it comprises, per 100 ml: - Water-based sign printing ink 50 - 99 ml - organic coloring compound 2.5 - 10 g - Acidity regulator 2.5 - 8.75 g, optionally, if necessary to complete the volume - solvent to complete 100 ml where the organic coloring compound ionizes in aqueous medium and presents at least two structural forms with different colors depending on the pH changing in the pH range between 3 and 8, the acidity regulator is a weak acid that has at least a pKa with a value between 2 and 2.4, the solvent is selected from the group of water, toluene, acetone, isopropyl alcohol or a mixture of at least two hydrocarbons from the group of 2-butoxyethyl acetate, butyl glycol acetate or N-methyl-2-pyrrolidone.

2. The composition according to claim 1, wherein the water-based screen printing ink is white, opaque, and matte.

3. The composition according to claim 1 or 2, wherein the different colored structural forms of the organic coloring compound differ by one proton and the compound has a pKa of 5 ± 2.

4. The composition according to claim 3, wherein the organic coloring compound has a pH transition range between 3.5 and 6.

5.

5. The composition according to any one of the preceding claims, wherein the organic coloring compound is selected from the group of methyl orange, methyl red, chlorophenol red, bromocresol green, bromophenol blue, bromocresol red, o-nitrophenol, p-nitrophenol, bromocresol violet, nitrozine yellow, and bromothymol blue.

6. The composition according to any one of the preceding claims, wherein the acidity regulator is selected from the group of tartaric acid, citric acid, phosphoric acid, citraconic acid and lactic acid.

7. The composition according to any one of the preceding claims, wherein the solvent is a mixture of 2-butoxyethyl acetate / butyl glycol acetate in a ratio of 1.5 / 1.

8. The composition according to any one of the preceding claims comprising, per 100 ml of white, opaque, water-based screen printing ink, 50 - 97.5 ml of bromocresol green, 2.5 - 10 g of citric acid, 2.5 - 8.75 g of solvent, if necessary to complete the volume: a mixture of 2-butoxyethyl acetate / butyl glycol acetate in a 1.5 / 1 ratio to complete 100 ml.

9. The composition according to any one of claims 1-7, comprising, per 100 ml white, opaque, water-based screen printing ink, 92 ml bromocresol green, 5 g tartaric acid, 6 g solvent, if necessary to complete the volume: a mixture of 2-butoxyethyl acetate / butyl glycol acetate in a 1.5 / 1 ratio to complete 100 ml.

10. The composition according to any one of claims 1-7, comprising, per 100 ml of white, opaque, water-based screen printing ink, 92 ml of methyl red, 4 g of citric acid, 3.5 g of solvent, if necessary to complete the volume: a mixture of 2-butoxyethyl acetate / butyl glycol acetate in a 1.5 / 1 ratio to complete 100 ml.

11. A device for detecting the presence of gamma-hydroxybutyric acid (GHB) in a sample, comprising a) a support with an upper surface and a lower surface b) at least one detection zone on the upper surface to which the composition of any one of claims 1 to 10 is attached.

12. The device according to claim 11, wherein the support is made of a waterproof material.

13. The device according to claim 12, wherein the support is made of a non-porous non-woven fabric (TNT) material.

14. The device according to claim 13, wherein the support is made of a TNT material of randomly placed and compressed high-density polyethylene fibers.

15. The device according to any one of claims 11 to 14, wherein the support is band-shaped and comprises at one end thereof an upper surface area to which an adhesive compound or material is attached.

16. The device according to any one of claims 11 to 15, comprising an information area explaining how to identify the presence of GHB in an aqueous solution after the detection area of ​​the device has been brought into contact with a sample of said solution.

17. The device according to any one of claims 11 to 16, comprising at least one detection zone on the upper surface to which the composition of any one of claims 8, 9 or 10 is attached.

18. The device according to claim 17, which is a device according to claim 12, 13, 14, 15 and 16.

19. Use of a composition according to any one of claims 1 to 10 or of a device according to any one of claims 11 to 18 for detecting the presence of GHB in an aqueous solution.

20. The use according to claim 19, wherein the aqueous solution is a beverage for human consumption.

21. The use according to claim 20, wherein the beverage is a non-alcoholic soft drink, an alcoholic beverage with an alcohol content less than or equal to 30 milliliters per 100 mi, or an alcoholic beverage with an alcohol content greater than 30 milliliters per 100 mi.

22. The use according to claim 19 or 20, wherein the beverage is selected from the group of non-alcoholic soft drinks, non-alcoholic beer, alcoholic beer, wine or spirits.

23. The use according to any one of claims 20 to 22, wherein the beverage is selected from the group of whisky, gin, rum, vodka or tequila, mixed or not with water or with a non-alcoholic beverage.

24. A method for preparing a device according to any one of claims 11 to 18, comprising the steps of: a) obtaining a composition according to any one of claims 1 to 10; b) printing said composition on a support by sehgraphic printing.

25. The process according to claim 24, which includes a prior step in which a support is obtained as defined in any one of claims 11 to 15.

26. The process according to any one of claims 24 or 25, wherein step a) comprises preparing the composition by means of the sub-steps of: - ai) mix the water-based screen printing ink, the organic coloring compound and the acidity regulator, - a. i) complete the desired volume with the organic solvent, - a. II) homogenize the mixture until a stable and uniform solution is achieved.

27. The method according to any one of claims 25 to 26, wherein the support is commercially available and, optionally, cut into the desired shape.

28. The method according to claim 27, wherein the device to be prepared is a device according to claim 14 and / or 15, and the preparation of the support includes Cut it into strips and, optionally, impregnate one end with an adhesive material on the surface where the composition will be printed.

29. The method according to any one of claims 24 to 28, wherein the stage of printing the composition onto the substrate by means of screen printing comprises the sub-steps of: (bi) preparing the mesh containing the design to be printed, emulsifying it with a photosensitive substance, fixing it to a frame so that it is taut, placing the design to be made on it, exposing it to light and removing the unhardened emulsion with water, leaving free the areas where the ink will pass; (b.ü) mounting the frame on which the mesh has been fixed in the screen printing equipment, on a support of the same which includes a system for aligning the support, (b.iii) applying the composition of the invention as ink to the mesh, depositing it on the same, without directly touching the design, and applying pressure with a squeegee to spread the composition that acts as ink uniformly over the mesh, b.iv) transferring the composition as ink to the support, allowing the composition to pass through the free areas of the mesh and be deposited directly onto the surface of the support; bv) applying a heat treatment to fix the composition of the invention to the support; b. vi) inspecting the support to verify that the composition has been fixed onto the area intended to act as a detection area.

30. The method according to any one of claims 24 to 29, wherein the support is a band of randomly placed and compressed high-density polyethylene fibers.

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