Simple and rapid screening and testing method for formaldehyde content in textile

Abstract

The invention provides a simple and rapid screening and testing method for formaldehyde content in textile, and belongs to the technical field of textile detection, and the method comprises the following steps: clipping the textile, adding a developing solution, and immediately sealing to obtain a sample; heating the sample in a constant-temperature water bath for 5 minutes + / -15 seconds; quickly cooling the heated sample, adding distilled water, standing, and taking supernate after layering; injecting the supernate into an electrochemical detection tank to form a three-electrode system; applying a constant potential, and recording a steady-state current value I within 30-90 seconds; and calculating the formaldehyde concentration according to a standard curve equation C = aI + b. According to the present invention, the high temperature color development reaction and the instant electrochemical detection are combined, the limitation of the traditional spectrophotometric method is broken through, the precision, the accuracy and the stability at the high temperature are good, the anti-interference ability is strong, and the wide application scene is provided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of textile detection, in particular to a simple and rapid screening test method for formaldehyde content in textiles. BACKGROUND

[0002] Textile formaldehyde detection technology has experienced several iterations since the 1970s. The traditional method has long relied on the acetylacetone spectrophotometric method. This method uses a 40℃ water bath to oscillate for 60 minutes for formaldehyde extraction, and then transfers the extracted liquid to add a color developing agent for a second 40℃ color development for 30 minutes. The whole process takes more than 90 minutes. Although the sealed bottle method that appeared later simplified the operation, the 24-hour detection period cannot meet the needs of modern textile industry for rapid customs clearance and instant quality control.

[0003] The rapid detection technology that emerged in the early 21st century tried to accelerate the reaction by increasing the temperature, but faced three bottlenecks: first, high temperature (> 60℃) caused the decomposition of traditional color developing agent acetylacetone, and the color developing stability dropped sharply; second, the release efficiency of formaldehyde inside the textile fiber was insufficient, and the detection rate was low after short-time treatment; third, the coexisting aldehyde substances (such as acetaldehyde) produced cross-reactions at high temperatures, causing false positives. In the past decade, although some studies have improved the permeability by adding surfactants or introduced masking agents to inhibit interference, a single improvement cannot simultaneously solve the contradictions of "high temperature-speed-selectivity". The existing rapid detection schemes either require complex pretreatment (such as distillation method), or rely on expensive instruments (such as HPLC), which are difficult to realize on-site low-cost screening.

[0004] Therefore, it is urgent to develop a single-step detection system that integrates high-temperature high-efficiency release, specific color development, and anti-interference ability in the field of textile safety supervision.

[0005] In view of this, the present application is proposed. SUMMARY

[0006] In order to solve the above technical problems, the present application provides a simple and rapid screening test method for formaldehyde content in textiles, which breaks through the traditional "first extraction and then color development" step-by-step mode, and innovates the 88℃-92℃ single-step integrated technology, which effectively improves the detection efficiency; combines high-temperature color development reaction with instant electrochemical detection, breaking through the limitations of traditional spectrophotometric method; and has good accuracy and precision.

[0007] The present application also provides a simple and rapid screening test method for formaldehyde content in textiles in the application of textile content detection.

[0008] In order to achieve the purpose of the present application, the present application provides a simple and rapid screening test method for formaldehyde content in textiles, which comprises the following steps: S1, cut the textile, add color developing solution, seal immediately, get sample; S2, heat the sample in constant temperature water bath for 5 min ± 15 s; S3, cool the heated sample quickly, and add distilled water and stand until stratification, then take supernatant; S4, inject the supernatant into an electrochemical detection cell to form an inserted three-electrode system; S5, apply a constant potential, and record the steady-state current value I within 30 s-90 s; S6, calculate the formaldehyde concentration according to the standard curve equation C = aI + b, wherein a and b are constants, C is the formaldehyde concentration with the unit of μg / mL, and I is the current value with the unit of μA. Further, a = 0.052, and b = 0.38.

[0009] Further, the heating time of the constant temperature water bath is 5 min.

[0010] Further, the heating temperature of the constant temperature is 90℃ ± 2℃. Further, the heating temperature of the constant temperature is 90℃.

[0011] Further, the cooling step in S3 is specifically using an ice water bath to cool for 3 min.

[0012] Further, the color developing solution is composed of acetylacetone, ammonium acetate, penetration promoter, interference masking agent, and color developing stabilizer.

[0013] Further, the constant potential is +0.35 V.

[0014] Further, the three-electrode system is composed of a working electrode, a counter electrode, and a reference electrode. The working electrode is a glassy carbon electrode substrate surface modified with a nano-gold-thiourea composite layer, the nano-gold particle size is 50 nm-80 nm, and the thiourea loading is 0.8 μg / mm 2 -1.2 μg / mm 2 . The counter electrode is a platinum wire electrode. The reference electrode is a silver-silver chloride electrode.

[0015] Further, the working electrode is a glassy carbon electrode substrate surface modified with a nano-gold-thiourea composite layer, the nano-gold particle size is 60 nm, and the thiourea loading is 1.0 μg / mm 2 .

[0016] Further, the preparation method of the nano-gold-thiourea composite layer is as follows: S1, polish the glassy carbon electrode to a mirror surface, and ultrasonically clean it in Al2O3 suspension and ultrapure water in sequence; S2, cyclic scanning at -0.2V~+1.5V potential in 0.5M H2SO4 solution for activation; S3, immersing in a mixed solution of HAuCl4 and KCl, wherein the concentration of HAuCl4 is 1mM, the concentration of KCl is 0.1M, and depositing gold nanoparticles at -0.4V constant potential for 60s to form a gold nanoparticle layer; S4, transferring to a pH=7.4 phosphate buffer solution containing 5mM thiourea, and self-assembling at +0.6V for 300s.

[0017] Further, the volume concentration of acetylacetone in the chromogenic solution is 0.2%-0.5%, the volume concentration of the penetration promoter is 0.05%-0.2%, the mass concentration of ammonium acetate is 20g / L-40g / L, the mass concentration of the interference masking agent is 0.5g / L-2.0g / L, and the mass concentration of the color development stabilizer is 1g / L-3g / L.

[0018] Further, the volume concentration of acetylacetone in the chromogenic solution is 0.4%, the volume concentration of the penetration promoter is 0.1%, the mass concentration of ammonium acetate is 30g / L, the mass concentration of the interference masking agent is 1.0g / L, and the mass concentration of the color development stabilizer is 1.5g / L.

[0019] Further, the penetration promoter is any one of Tween 20, isopropyl alcohol or ethanol; The interference masking agent is any one of urea or sulfamic acid; The color development stabilizer is thiourea.

[0020] Further, the penetration agent is Tween 20; The interference masking agent is urea.

[0021] Further, in the S1 step, when the textile is cut, it is cut into fragments with an edge length of ≤5mm.

[0022] The application also provides an application of a simple and rapid screening and selection test method for formaldehyde content in textiles in detection of formaldehyde content in textiles.

[0023] The application embodiment has the following technical effects: In the present application, high temperature is used for formaldehyde detection, and the time of high temperature extraction is shortened to within 10 min, while through the improvement of the formula of the chromogenic solution, the problems of coexisting interference under high temperature and color stability are solved, the huge challenges of high temperature to the stability and selectivity of the color system are overcome, and the complexity and cost of operation are reduced; the high-temperature color reaction is combined with instant electrochemical detection, which breaks through the limitations of traditional spectrophotometry, and has good precision, accuracy and stability under high temperature, and has strong anti-interference ability, and has a wide range of application scenarios. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the specific embodiments or prior art description will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0025] Figure 1 : The color development state of the quality control sample of 20mg / kg, 75mg / kg, 300mg / kg using the chromogenic solution in Example 1; from left to right, the color development state of 300mg / kg, 75mg / kg, 20mg / kg, respectively. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical scheme and advantages of the present application more clear, the technical scheme of the present application will be described clearly and completely below. Obviously, the described embodiments are only some of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application.

[0027] In the first aspect, the present application provides a simple and rapid screening test method for the content of formaldehyde in textiles. The present application breaks through the traditional "first extraction and then color development" step-by-step mode, and creates an 88℃-92℃ single-step integrated technology, which effectively improves the detection efficiency; at the same time, it has good accuracy and precision.

[0028] In some embodiments, the method comprises the following steps: S1, cutting the textile, adding the chromogenic solution, immediately sealing, and obtaining the sample; S2, heating the sample in a constant temperature water bath for 5min±15s; S3, rapidly cooling the heated sample, adding distilled water and standing, and then taking the supernatant after layering; S4, injecting the supernatant into an electrochemical detection cell to form an inserted three-electrode system; S5, apply a constant potential, record the steady-state current value I for 30-90s; S6, calculate the formaldehyde concentration according to the standard curve equation C=aI+b, wherein a and b are constants, C is the formaldehyde concentration, the unit is pg / mL; I is the current value, the unit is pA; a=0.052, b=0.38.

[0029] Wherein, 0.052 is the coefficient of the steady-state current value I; 0.38 is the constant term. The above data is fitted by the least square method to obtain the linear equation of current I with respect to concentration C; then the equation is converted to obtain the expression of concentration C with respect to current I, and simplified and corrected.

[0030] In some embodiments, the temperature of the constant temperature heating is 90℃±2℃.

[0031] In the present application, the three-step process of extraction, transfer and color development is simplified to single container operation by one-step method, so as to realize the release and color development of formaldehyde in a short time, which greatly improves the detection efficiency compared with the traditional method. The sealing is immediately added after the color developing solution, so as to prevent the volatilization and loss of formaldehyde, so that the recovery rate of formaldehyde is ≥5%.

[0032] Then the sample is accurately heated at 90℃±2℃ for 5min±15s, the high temperature can improve the diffusion efficiency of formaldehyde molecules, and the swelling of fibers can accelerate the release of formaldehyde; at the same time, 90℃ is the decomposition critical point of acetylacetone, when >95℃, the half-life of acetylacetone is <1min, and when the temperature <85℃, the release efficiency is less than 80%, setting the temperature at 90℃±2℃ can not only ensure the release of formaldehyde, but also provide a stable thermal stability window for acetylacetone, and prevent the occurrence of side reactions.

[0033] The oxidation current value is detected by an electrochemical sensor, which breaks through the limitation of traditional spectrophotometry, and integrates high-temperature color development and electrochemical real-time detection for the first time: thiourea in the color developing solution has the dual functions of stabilizer and electrode modifier, and the nano-gold layer enhances the electron transfer efficiency, solving the problems of interference shielding and signal attenuation under high temperature. The method is simple in operation and low in cost, which greatly shortens the detection process.

[0034] The core component of the colorimetric reagent used in this invention is acetylacetone. In a buffer environment provided by ammonium acetate, it specifically reacts with formaldehyde to generate DDL (3,5-diacetyl-1,4-dihydropyridine). The dihydropyridine structure in the DDL molecule exhibits significant electrochemical activity; it can undergo oxidation on the electrode surface, losing electrons and thus generating a measurable current. The core of the detection is measuring the current generated during the redox reaction on the working electrode. The generation of DDL affects the current value. When a suitable positive potential is applied (set to 0.35V in this application), DDL is oxidized on the surface of the working electrode (nano-gold-thiourea modified electrode). During this reaction, the DDL molecule loses electrons (2e⁻¹). - Electrons flow from the electrodes to the DDL molecules, and then form an electric current through an external circuit. According to Faraday's law, the magnitude of the current (I) is directly proportional to the concentration of DDL in the reaction.

[0035] Since one formaldehyde molecule quantitatively generates one DDL molecule, the concentration of DDL is equal to the concentration of formaldehyde. Furthermore, because the current (I) is equal to the concentration of DDL, ultimately, the current (I) is equal to the concentration of formaldehyde (C). This is the fundamental reason why the standard curve C = aI + b holds true. The measured current value directly reflects the concentration of formaldehyde in the sample.

[0036] In some embodiments, the cooling step in S3 specifically involves cooling with an ice-water bath for 3 minutes.

[0037] Rapid cooling using an ice-water bath lowers the reaction system temperature quickly to below 25°C, terminating the DDL generation reaction. Simultaneously, the low temperature promotes fiber fragment aggregation, accelerating delamination. Using an ice-water bath instead of natural cooling not only shortens the reaction time but also prevents over-development that could lead to absorbance shifts.

[0038] In some embodiments, the color developing solution is composed of acetylacetone, ammonium acetate, a penetration enhancer, an interference masking agent, and a color developing stabilizer.

[0039] In some embodiments, the three-electrode system consists of a working electrode, a counter electrode, and a reference electrode; The working electrode is a glassy carbon electrode substrate with a surface modified with a gold-thiourea composite layer, wherein the gold nanoparticles have a size of 50nm-80nm and the thiourea loading is 0.8μg / mm². 2 -1.2μg / mm 2 ; The counter electrode is a platinum wire electrode; The reference electrode is a silver-silver chloride electrode.

[0040] In some embodiments, the preparation method of the nano-gold-thiourea composite layer is as follows: S1, polish the glassy carbon electrode to mirror surface, and ultrasonic clean in Al2O3 suspension and ultrapure water in turn; S2, activate by cyclic scanning in 0.5M H2SO4 solution at-0.2V~+1.5V potential; S3, immerse in mixed solution of HAuCl4 and KCl, wherein the concentration of HAuCl4 is 1mM, the concentration of KCl is 0.1M, and deposit at-0.4V constant potential for 60s to form nanometer gold layer; S4, transfer to pH=7.4 phosphate buffer solution containing 5mM thiourea, and self-assemble at+0.6V for 300s.

[0041] In the application, the thiourea in the color developing solution not only inhibits the fading of DDL, but also forms a molecular imprinting layer on the electrode surface, which selectively captures formaldehyde and repels acetaldehyde through-SH groups; meanwhile, the 50-80nm gold particles provide a three-dimensional conductive network, which makes the electron transfer rate increase to 5.8 times of that of the bare electrode; the thiourea composite layer forms a thermally stable crosslinked structure at 90℃, solving the problem of electrode deactivation at high temperature.

[0042] In some embodiments, the volume concentration of acetylacetone in the color developing solution is 0.2%-0.5%, the volume concentration of the penetration promoter is 0.05%-0.2%, the mass concentration of ammonium acetate is 20g / L-40g / L, the mass concentration of the interference masking agent is 0.5g / L-2.0g / L, and the mass concentration of the color developing stabilizer is 1g / L-3g / L.

[0043] In some embodiments, the volume concentration of acetylacetone in the color developing solution is 0.4%, the volume concentration of the penetration promoter is 0.1%, the mass concentration of ammonium acetate is 30g / L, the mass concentration of the interference masking agent is 1.0g / L, and the mass concentration of the color developing stabilizer is 1.5g / L.

[0044] In the application, acetylacetone can specifically react with formaldehyde to generate a yellow product, and the substance has high color developing sensitivity; ammonium acetate provides a buffer system for the whole reaction; the penetration promoter itself is a non-ionic surfactant, which reduces the surface tension, wets the fiber pores, thereby breaking through the fiber barrier and accelerating the dissolution of formaldehyde from the fiber; the interference masking agent can form a stable cyclic adduct with other interference substances, mask the interference of acetaldehyde and propyl aldehyde, block the reaction of acetaldehyde and propyl aldehyde with acetylacetone, and reduce false positives; the color developing stabilizer can prevent the fading of color developing oxides, inhibit the oxidation of DDL, and prolong the reading time.

[0045] The interference masking agent and the color developing stabilizer are mutually synergistic, effectively solve the contradiction between the release efficiency and the selectivity at high temperature, make the reaction system be able to give consideration to the release efficiency and the selectivity, can not only reduce the detection time, but also can guarantee the precision of the reaction; meanwhile, the color developing agent is selected to be non-toxic organic matter, replaces the traditional toxic stabilizer, realizes environmental protection and safety.

[0046] In addition, the concentration range of each substance is limited in the application. For example, the volume concentration of the penetration promoter is limited to 0.05%-0.2%, on the one hand, to prevent the concentration from being too high to cause the turbidity of the solution to rise and avoid light scattering interference; on the other hand, to prevent the concentration from being too low to cause the insufficient wetting of the fiber and cause the formaldehyde to be difficult to overflow. The concentration of urea is limited to 0.5g / L-2.0g / L, to avoid the content being too high to compete with the combination of formaldehyde, and to prevent the content from being too low to cause the insufficient masking rate of other substances such as acetaldehyde.

[0047] Under the optimal ratio, Tween 20 can promote the penetration of acetylacetone into the fiber, and urea can selectively chelate interfering aldehydes at high temperature, and ammonium acetate can communicate the best pH of the reaction system for the reaction system.

[0048] In some embodiments, the penetration promoter is any one of Tween 20, isopropyl alcohol or ethanol; The interference masking agent is any one of urea or sulfamic acid; The color developing stabilizer is thiourea.

[0049] In some embodiments, the penetration agent is Tween 20; The interference masking agent is urea.

[0050] Compared with other surfactants, the polyoxyethylene of Tween 20 can still maintain hydrophilicity under the condition of 90℃; compared with sulfamic acid, the reaction rate constant of urea is higher, which is more suitable for the efficient reaction system of the application; and thiourea plays a unique role in the reaction system, can form a charge transfer complex with the conjugated double bond of DDL, and prevent photooxidation.

[0051] In some embodiments, when the textile is cut in the S1 step, it is cut into fragments with an edge length of ≤5mm.

[0052] On the other hand, the application also provides a simple and rapid screening test method for the formaldehyde content in textiles and the application of the method in the detection of the formaldehyde content in textiles.

[0053] The following will be described in conjunction with specific embodiments: Embodiment 1 S1, select white waterproof cloth with full printing as a sample, cut it into fragments with an edge length of ≤5mm to obtain the sample.

[0054] S2. Preparation of colorimetric reagent: Mix 4 mL of acetylacetone and 1 mL of Tween 20, then add an appropriate amount of deionized water and mix well to obtain mixture 1; add 30 g of acetamide, 1 g of urea and 1.5 g of thiourea to mixture 1 to obtain mixture 2; bring mixture 2 to a final volume of 1 L to obtain the colorimetric reagent.

[0055] S3. Weigh 0.5g of the sample into a reaction flask, add 25mL of the pre-prepared colorimetric solution, and then seal immediately.

[0056] S4. Heat the reaction flask containing the sample and colorimetric solution in a water bath at a constant temperature of 90°C for 5 minutes.

[0057] S5. Quickly place the heated sample in an ice-water bath to cool for 3 minutes. Then add distilled water to the reaction flask to make up to 25 mL. Let it stand until it separates into layers, and take the supernatant.

[0058] S6. Prepare a nano-gold-thiourea composite layer. Take a glassy carbon electrode with a diameter of 3 mm, polish it to a mirror surface, and then ultrasonically clean it in 0.05 μm Al2O3 suspension and ultrapure water. Activation was performed in 0.5M H2SO4 solution with cyclic scanning potentials ranging from -0.2V to +1.5V. A nano-gold layer was formed by immersing the sample in a 0.1M KCl solution containing 1mM HAuCl4 and depositing it at a constant potential of -0.4V for 60s. Transfer to pH 7.4 phosphate buffer containing 5 mM thiourea and self-assemble at +0.6 V for 300 s.

[0059] S7. Insert the supernatant into the electrochemical detection cell and then insert the three-electrode system; Apply a constant potential of +0.35V and record the steady-state current value I (μA) over 30-90s. The formaldehyde concentration was calculated based on the standard curve equation C(μg / mL) = 0.052I + 0.38.

[0060] Example 2 The specific implementation method is consistent with Example 1, except that the ratio of each substance in the colorimetric reagent is changed. Specifically, 2 mL of acetylacetone and 500 μL of Tween 20 are mixed, and then an appropriate amount of deionized water is added and mixed evenly to obtain mixture 1; 20 g of acetamide, 0.5 g of urea and 1 g of thiourea are added to mixture 1 to obtain mixture 2; mixture 2 is brought to a final volume of 1 L to obtain the colorimetric solution.

[0061] Example 3 The specific embodiment is consistent with embodiment 1, only the ratio of each substance in the color developing agent is changed, specifically: 5mL of acetylacetone and 2mL of Tween 20 are mixed, then an appropriate amount of deionized water is added and mixed uniformly to obtain a mixed solution 1; 40g of acetamide, 2g of urea and 3g of thiourea are added to the mixed solution 1 to obtain a mixed solution 2; the mixed solution 2 is diluted to 1L to obtain a color developing solution.

[0062] Comparative example 1 Step A: The white waterproof cloth sample is cut into 5mm x 5mm pieces, then the cut textile sample is weighed and placed in a No. 1 triangular flask, 100ml of distilled water is added to the weighed textile sample, the stopper is tightly covered, and the sample is ultrasonically treated at 25℃ for 20 minutes and then placed in a water bath oscillator at 38℃, and oscillated at a frequency of 110 times / min for 65 minutes, ready for use; wherein the textile sample weighs 1g; the textile sample is stored at a temperature of 8℃.

[0063] Step B: The textile sample after oscillation in step A is filtered into a No. 2 triangular flask with a glass sand core funnel, the filtrate is cooled to room temperature at a rate of 0.5℃ / min, 5mL of the filtrate is taken and placed in a No. 1 test tube as a sample solution, 5mL of distilled water is taken and placed in a No. 2 test tube as a blank, then 5mL of acetylacetone reagent is added to the sample solution and the distilled water respectively, the No. 1 and No. 2 test tubes are shaken for 3s respectively, the stoppers are tightly covered, and the test tubes are placed in a water bath at 38℃ for color development for 35min.

[0064] The preparation process of the acetylacetone reagent is as follows: 150g of ammonium acetate is added to a 1000mL volumetric flask, then 800mL of water is added to dissolve the ammonium acetate, then 3mL of glacial acetic acid and 2mL of acetylacetone are added in sequence, shaken uniformly, and finally diluted with water to the mark, and the acetylacetone reagent is obtained; the acetylacetone reagent is stored in a brown bottle, and can be used after 12h of storage.

[0065] Step C, the No. 1 and No. 2 test tubes after color development in step B are taken out, cooled naturally at a temperature of 23℃ for 35min in the dark, then the absorbance is measured at a wavelength of 412nm with a 10mm absorption cell in a spectrophotometer, and the formaldehyde content is calculated.

[0066] Comparative example 2 The textile is cut into ≤5mm pieces, 1.00g is accurately weighed and placed in a 150mL conical flask; 100mL of distilled water is added, the stopper is tightly covered, and it is placed in a 40℃ constant temperature water bath oscillator and oscillated at 120r / min for 60 minutes; The extraction liquid is immediately filtered with a glass sand core funnel, and the filtrate is cooled in an ice water bath for 10min to room temperature; Take 5 mL filtrate to the test tube, add 5 mL acetylacetone reagent (0.4% acetylacetone + 30% ammonium acetate aqueous solution), shake well and place in 40°C water bath for 35 minutes; Take out the test tube and cool to room temperature, and measure the absorbance at 412 nm wavelength.

[0067] Experimental Example 1 Uniformly sample the quality control samples of 20 mg / kg, 75 mg / kg, and 300 mg / kg, respectively, add the color developing agent in Example 1, and react using the reaction method in Example 1. The experimental results are shown in Figure 1 The color developing solution is slightly yellow at a low concentration of 20 mg / kg; it presents a clear yellow color at a medium concentration of 75 mg / kg, similar to freshly squeezed lemon juice, which can be directly identified by the naked eye without comparison, and the color is uniform and stable without turbidity or precipitation; the color developing solution is bright yellow at a high concentration of 300 mg / kg, and the color saturation is high without turbidity.

[0068] Experimental Example 2 Compare the detection times of Example 1 and Comparative Examples 1-2, and the experimental results are shown in Table 1.

[0069] Table 1: Comparison of detection times of examples and comparative examples Experimental Example 3 1. Preparation of spiked samples Spray the formaldehyde standard solution of 20 mg / kg, 75 mg / kg, and 300 mg / kg uniformly onto the cotton cloth, and control the error of the spiked concentration to be ≤±5%; Seal and balance for 24 h to ensure that the formaldehyde penetrates the fibers; Cut the sample into 5 mm pieces.

[0070] The recovery rate (measured concentration / spiked concentration) × 100% is 80%-115%.

[0071] The precision RSD (standard deviation / average concentration) × 100% is ≤10%.

[0072] The experimental results are shown in Tables 2-3.

[0073] Table 2: Measured concentration and current value in Example 1-Example 3 Table 3: Performance evaluation of examples and comparative examples From the above experimental data, it can be seen that the recovery rate of the full concentration range in Example 1 is 98.5%-101.2%, which meets the standard and can effectively prove the synergistic effect of the color developing agent used in the application at high temperature. In addition, the sensitivity, accuracy and reaction time of the method used in the application are shorter.

[0074] In Example 2, the sensitivity decreased due to the low content of acetylacetone and penetrant, so the recovery rate was low at 200 mg / kg. In Example 3, the high content of urea caused urea to compete with formaldehyde, resulting in a positive deviation in Example 3.

[0075] Comparative Example 1 is a traditional ultrasonic method, and Comparative Example 2 is a GB standard method. In Comparative Example 1, ultrasonic + low temperature leads to insufficient release efficiency of formaldehyde, resulting in poor sensitivity and accuracy. The GB standard method takes longer. Therefore, from the above experimental data, it can be seen that the application can not only effectively improve the detection efficiency, but also improve the detection accuracy and precision.

[0076] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the application, and not to limit them; although the application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the embodiments of the application.

Claims

1. A simple and rapid screening test method for formaldehyde content in a textile, characterized in that, It comprises the following steps: S1, cut the textile, add color developing solution, seal immediately, and obtain a sample; S2, heat the sample in a constant temperature water bath for 5 min±15s; S3, quickly cool the heated sample, add distilled water, and stand until stratification, then take the supernatant; S4, inject the supernatant into an electrochemical detection cell to form a three-electrode system; S5, apply a constant potential, and record the steady-state current value I within 30s-90s; S6, calculate the formaldehyde concentration according to the standard curve equation C=aI+b; Wherein, a and b are constants, C is the formaldehyde concentration, and the unit is μg / mL; I is the current value, and the unit is μA; The color developing solution is composed of acetylacetone, ammonium acetate, a penetration promoter, an interference masking agent, and a color developing stabilizer.

2. A simple and rapid screening test method for formaldehyde content in a textile product as claimed in claim 1, wherein, The temperature of the constant temperature water bath heating is 90℃±2℃.

3. A simple and rapid screening test method for formaldehyde content in a textile product as claimed in claim 1, wherein, The cooling step in S3 is specifically using an ice water bath to cool for 3 min.

4. The simple and rapid screening test method for formaldehyde content in a textile according to claim 1, characterized in that, The three-electrode system is composed of a working electrode, a counter electrode, and a reference electrode; The working electrode is a glass carbon electrode substrate surface modified with a nano-gold-thiourea composite layer, the nano-gold particle size is 50nm-80nm, and the thiourea loading is 0.8μg / mm 2 -1.2μg / mm 2 ; The counter electrode is a platinum wire electrode; The reference electrode is a silver-silver chloride electrode.

5. The simple and rapid screening test method for formaldehyde content in a textile according to claim 4, characterized in that, The preparation method of the nano gold-thiourea composite layer is: S1, polish the glassy carbon electrode to a mirror surface, and ultrasonically clean it in Al2O3 suspension and ultrapure water; S2, activate by cyclic scanning at a potential of-0.2V~+1.5V in a 0.5M H2SO4 solution; S3, immerse in a mixed solution of HAuCl4 and KCl, wherein the concentration of HAuCl4 is 1mM, and the concentration of KCl is 0.1M, and deposit nano gold layer at-0.4V constant potential for 60s; S4, transfer to a phosphate buffer solution with pH=7.4, which contains 5mM thiourea, and self-assemble at +0.6V for 300s.

6. The simple and rapid screening test method for formaldehyde content in a textile according to claim 1, characterized in that, The volume concentration of acetylacetone in the color developing solution is 0.2%-0.5%, the volume concentration of the penetration promoter is 0.05%-0.2%, the mass concentration of ammonium acetate is 20g / L-40g / L, the mass concentration of the interference masking agent is 0.5g / L-2.0g / L, and the mass concentration of the color developing stabilizer is 1g / L-3g / L.

7. A simple and rapid screening test method for formaldehyde content in a textile product according to claim 6, characterized in that, The volume concentration of acetylacetone in the color developing solution is 0.4%, the volume concentration of the penetration promoter is 0.1%, the mass concentration of ammonium acetate is 30g / L, the mass concentration of the interference masking agent is 1.0g / L, and the mass concentration of the color developing stabilizer is 1.5g / L.

8. A simple and rapid screening test method for formaldehyde content in a textile product according to claim 7, characterized in that, The penetration promoter is any one of Tween 20, isopropyl alcohol, or ethanol; The interference masking agent is any one of urea or sulfamic acid; The color developing stabilizer is thiourea.

9. A simple and rapid screening test method for formaldehyde content in a textile product according to claim 8, characterized in that, The penetration promoter is Tween 20. The interference masking agent is urea.

10. The application of a simple and rapid screening test method for formaldehyde content in a textile product according to any one of claims 1-9 in the detection of formaldehyde content in a textile product.

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