Method for detecting polyhexamethylene biguanide hydrochloride in textile

Abstract

The invention belongs to chemical detection of textiles, provides a method for detecting polyhexamethylene biguanide hydrochloride in textiles, and belongs to the technical field of chemical detection. According to the method, ultrasonic extraction is adopted for sample pretreatment, and the content of polyhexamethylene biguanide hydrochloride in the textile is detected by optimizing chromatographic conditions in HPLC (High Performance Liquid Chromatography) analysis. According to the detection method, the content of the polyhexamethylene biguanide hydrochloride in the textile can be simply, accurately and sensitively measured, and the quality of textile products is controlled, so that smooth export of the textile products in China is effectively guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of textile chemical detection, and in particular to a method for detecting polyhexamethylene biguanide hydrochloride in textiles. Background Art

[0002] Polyhexamethylene biguanide hydrochloride (PHMB) is a broad-spectrum antibacterial agent. It is widely used in textiles, cosmetics, disinfectants and other fields because of its strong bactericidal ability, broad-spectrum high efficiency, easy solubility in water, and odorless aqueous solution. Polyhexamethylene biguanide hydrochloride itself is positively charged. It can block the respiratory tract of microorganisms and inhibit the division of bacteria and viruses after mutual adsorption with negatively charged microorganisms. The biguanide group can also bind to the phosphatidylglycerol bilayer on the surface of bacteria, destroy the bilayer, increase the fluidity and permeability of the cell membrane, and eventually cause the bacteria to rupture and die. The effect of PHMB on the cell membrane also exists on mammalian cells. PHMB ingested through food, water and skin contact may endanger human health. As early as the 1970s, ICI Corporation of the United States first prepared polyhexamethylene biguanide hydrochloride. In 2011, the European Chemicals Agency identified polyhexamethylene biguanide hydrochloride as a suspected carcinogen. In 2013, EU Regulation No. 944 classified polyhexamethylene biguanide hydrochloride as a carcinogenic, teratogenic and mutagenic substance (CMR2 substance). In the same year, EU Biocidal Products Regulation 528 was officially implemented, and polyhexamethylene biguanide hydrochloride was included in the scope of control. In 2017, the European Commission reduced the limit of polyhexamethylene biguanide hydrochloride in the original Cosmetics Regulation 1223 from 0.3% to 0.1%, and banned its use in products that may cause inhalation exposure to the lungs of end users. In April 2021, the EU RAPEX notified that an antibacterial treated polyester fabric mask contained PHMB. The alert number was: A12 / 00538 / 21. The notification pointed out that inhalation of PHMB is harmful and may cause skin allergic reactions. Through inhalation, repeated contact can cause damage to organs and is also suspected of being carcinogenic.

[0003] Polyhexamethylene biguanide hydrochloride is mainly used as an antibacterial and deodorizing finishing agent in textiles. Fabrics finished with polyhexamethylene biguanide hydrochloride are mainly used to manufacture underwear, socks, masks and other products. Polyhexamethylene biguanide hydrochloride can enter the human body through food, water, inhalation, skin contact and other ways, and cause carcinogenic, teratogenic and mutagenic hazards to the human body. At present, the regulations on polyhexamethylene biguanide hydrochloride mainly focus on disinfectants, cosmetics, toy dyes, etc. There are currently no domestic and foreign literature and standards for the detection of PHMB in textiles. In order to respond to foreign regulatory requirements in a timely manner, improve market supervision capabilities, meet corporate product quality control needs, and protect consumer health, it is urgent to establish an analytical method for polyhexamethylene biguanide hydrochloride in textiles.

[0004] At present, the detection methods for polyhexamethylene biguanide hydrochloride are mainly concentrated in disinfectant products, using ultraviolet spectrophotometry and capillary electrophoresis respectively. By reviewing the papers published at home and abroad, we found that in addition to the above two methods, there are also high performance liquid chromatography and ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry. It is mainly used for the detection of products such as disinfectants, eyeglass care solutions, swimming pool water, eye drops, etc. There is no detection method for polyhexamethylene biguanide hydrochloride in textiles.

[0005] The textile industry is a pillar industry in my country and an important export-earning industry in my country. It has a significant impact on the national economy. The EU is the main export region. Establishing the determination standard of polyhexamethylene biguanide hydrochloride content in light textile products is of great significance to meet new international requirements, break foreign technical barriers, and ensure the smooth export of my country's textile products. Summary of the invention

[0006] The present invention aims to provide a method for simply, accurately and sensitively detecting polyhexamethylene biguanide hydrochloride in textiles, thereby making up for the defect of the prior art that there is no method for detecting polyhexamethylene biguanide hydrochloride in textiles.

[0007] To achieve the above object, the technical solution of the present invention provides a method for detecting polyhexamethylene biguanide hydrochloride in textiles, the method comprising the following steps:

[0008] (1) Sample pretreatment: Add the textile to be tested into the extraction solvent for ultrasonic extraction and filter to obtain the sample test solution;

[0009] (2) High performance liquid chromatography detection: The sample test solution is analyzed according to the following chromatographic conditions to obtain a chromatogram, and the content of polyhexamethylene biguanide hydrochloride in the textile is determined by analytical calculation based on the chromatogram.

[0010] In some embodiments, the extraction solvent used in the ultrasonic extraction in step (1) is composed of ammonium chloride solution and methanol, and the pH value of the ammonium chloride solution is adjusted by hydrochloric acid. Preferably, the concentration of the ammonium chloride solution is 0.5mol / L to 2.0mol / L, the volume fraction of the ammonium chloride solution is 20 to 70%, and the pH value is 1.0 to 3.0. More preferably, the concentration of the ammonium chloride solution is 1.8mol / L, the volume fraction of the ammonium chloride solution is 40%, and the pH value is 1.8.

[0011] In some embodiments, the ultrasonic extraction in step (1) is performed by one ultrasonic extraction.

[0012] In some embodiments, the mass ratio of the textile to be tested to the extraction solvent in step (1) is 1:(15-25), preferably 1:20.

[0013] In some embodiments, the extraction time of the ultrasonic extraction in step (1) is 40 min to 60 min, preferably 50 min.

[0014] In some embodiments, the extraction temperature of the ultrasonic extraction in step (1) is 50°C to 80°C, preferably 60°C to 75°C, and more preferably 70°C.

[0015] In some embodiments, the volume of the extraction solution for ultrasonic extraction in step (1) is 15 mL to 35 mL, preferably 19 mL to 30 mL, and more preferably 20 mL.

[0016] In some embodiments, the filter membrane used in the filtration in step (1) is selected from an organic filter membrane with a pore size of 0.45 μm, preferably a polytetrafluoroethylene filter membrane, and more preferably a polytetrafluoroethylene filter membrane produced by Tianjin Jinteng Experimental Equipment Co., Ltd.

[0017] In some embodiments, the high performance liquid chromatography in step (2) uses the following conditions:

[0018] Chromatographic column: C18 liquid chromatography column or cyano chromatography column, 4.6×150mm, 5μm or 4.6×75mm, 3.5μm,

[0019] Column temperature: 30℃~50℃,

[0020] Mobile phase A: water,

[0021] Mobile phase B: phosphoric acid aqueous solution, volume fraction 0.1‰-1.2‰,

[0022] Mobile phase C: acetonitrile,

[0023] Flow rate: 0.8 mL / min to 1.2 mL / min, preferably 1 mL / min,

[0024] The elution gradient is:

[0025] 0min~1min, mobile phase A: 94%, mobile phase B: 1%, mobile phase C: 5%;

[0026] 1min~12min, mobile phase A: 59%, mobile phase B: 1%, mobile phase C: 40%;

[0027] 12min~20min, mobile phase A: 0%, mobile phase B: 60%, mobile phase C: 40%;

[0028] 20min~27min, mobile phase A: 94%, mobile phase B: 1%, mobile phase C: 5%;

[0029] Running time: 27 minutes.

[0030] In some embodiments, the detector used is DAD, and the detection wavelength is 236 nm.

[0031] The present invention provides a method for detecting polyhexamethylene biguanide hydrochloride in textiles, the method comprising the following steps:

[0032] (1) Sample pretreatment: Add the textile to be tested into the extraction solvent for ultrasonic extraction and filter to obtain the sample test solution;

[0033] (2) High performance liquid chromatography detection: analyzing the sample test solution according to the following chromatographic conditions to obtain a chromatogram, and determining the content of polyhexamethylene biguanide hydrochloride in the textile by analytical calculation based on the chromatogram;

[0034] Wherein, the extraction solvent in step (1) is composed of ammonium chloride solution and methanol, the volume fraction of the ammonium chloride solution is 20% to 70%, the concentration is 0.5 to 2.0 mol / L, and the pH value is 1.5 to 4.0;

[0035] The chromatographic conditions in step (2) include:

[0036] Chromatographic column: C18 liquid chromatography column or cyano chromatography column, 4.6×150mm, 5μm or 4.6×75mm, 3.5μm,

[0037] Column temperature: 30℃~50℃,

[0038] Mobile phase A: water,

[0039] Mobile phase B: phosphoric acid aqueous solution, volume fraction 0.1‰~1.2‰,

[0040] Mobile phase C: acetonitrile,

[0041] Flow rate: 0.8 mL / min to 1.2 mL / min, preferably 1 mL / min,

[0042] The elution gradient is:

[0043] 0min~1min, mobile phase A: 94%, mobile phase B: 1%, mobile phase C: 5%;

[0044] 1min~12min, mobile phase A: 59%, mobile phase B: 1%, mobile phase C: 40%;

[0045] 12min~20min, mobile phase A: 0%, mobile phase B: 60%, mobile phase C: 40%;

[0046] 20min~27min, mobile phase A: 94%, mobile phase B: 1%, mobile phase C: 5%;

[0047] Running time: 27 minutes.

[0048] In some embodiments, the detector used is DAD, and the detection wavelength is 236 nm.

[0049] Different from the prior art, the above technical scheme establishes a method for detecting polyhexamethylene biguanide hydrochloride in textiles. This method can simply, quickly and accurately obtain the content of polyhexamethylene biguanide hydrochloride in the tested textiles through sample pretreatment and high performance liquid chromatography detection. The detection limit of this detection method is 60 mg / kg, and the quantitative limit is 200 mg / kg; the detection limit is low and has high sensitivity, which can realize the determination of trace polyhexamethylene biguanide hydrochloride in textiles. At the same time, this method has high detection precision and accuracy. At the three spiked levels of quantitative limit, five times quantitative limit and ten times quantitative limit, the average recovery rate of polyhexamethylene biguanide hydrochloride is 90.1% to 100.0%, and the relative standard deviation is 1.09% to 4.31%.

[0050] In some embodiments, in the sample pretreatment step, the fabric to be tested is cut into pieces of about 5 mm×5 mm before use.

[0051] In some embodiments, the applicant compared the retention and separation effects of C18 liquid chromatography column and cyano column on polyhexamethylene biguanide hydrochloride. It was found that for C18 liquid chromatography columns of different specifications, either the PHMB peak time was earlier (peaking near the solvent peak), or multiple peaks would appear, which would affect the qualitative and quantitative analysis of PHMB; for three different specifications of cyano chromatography columns of 250mm (column length) × 4.6mm (inner diameter) × 5μm (particle size), 150mm (column length) × 4.6mm (inner diameter) × 5μm (particle size), 75mm (column length) × 4.6mm (inner diameter) × 3.5μm (particle size), by adjusting different mobile phases and proportions and pH values ​​to examine the chromatographic peak, it was found that when a 250mm chromatographic column was used, the chromatographic peak shape was relatively poor, while when a 150mm or 75mm chromatographic column was used, a complete chromatographic peak could be obtained.

[0052] In some embodiments, the textile is made of cotton, linen, silk, or polyester.

[0053] By using the detection method according to the embodiment of the present invention, the content of polyhexamethylene biguanide hydrochloride in textiles can be simply, accurately and sensitively determined, and the quality of textile products can be controlled, thereby effectively ensuring the smooth export of my country's textile products. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 This is a diagram showing the extraction effect of the volume fraction (%) of ammonium chloride in the extraction solution composed of ammonium chloride solution and methanol on the positive sample in Example 1.

[0055] Figure 2 This is a diagram showing the extraction effect of the ammonium chloride solution concentration (mol / L) in the extraction solution composed of ammonium chloride solution and methanol on the positive sample in Example 1.

[0056] Figure 3 This is a diagram showing the extraction effect of the pH value of the ammonium chloride solution in the extraction solution composed of ammonium chloride solution and methanol on the positive sample in Example 1.

[0057] Figure 4 This is a diagram showing the effect of extraction time on the extraction of positive samples in Example 1.

[0058] Figure 5 This is a diagram showing the effect of extraction temperature on extraction yield in Example 1.

[0059] Figure 6 It is the spectrum of PHMB standard solution in Example 1.

[0060] Figure 7 This is an influence diagram of the volume fraction of phosphoric acid in the mobile phase phosphoric acid aqueous solution in Example 1.

[0061] Figure 8 It is the HPLC chromatogram of the PHMB standard solution in Example 1.

[0062] Fig. 9 It is the HPLC chromatogram of the actual sample in Example 1. DETAILED DESCRIPTION

[0063] For ease of understanding, the application will be described more fully below, and preferred embodiments of the application are provided. However, the application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive. In the embodiment, if specific techniques or conditions are not indicated, the techniques or conditions described in the document in this area or according to the product specification are carried out. Reagents used or instruments that do not indicate manufacturers are conventional products that can be obtained through the market.

[0064] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0065] In the present invention, the detection instrument used is:

[0066] Liquid chromatograph (LC-20AD, Shimadzu Corporation, Japan) equipped with quaternary pump and diode array detector (DAD); electronic balance (CPA324S, Sartourius, Germany); ultrasonic extractor (SB25-12DT, Ningbo Xinzhi Biotechnology Co., Ltd.); 50 mL stoppered glass extractor, tubular; 0.45 μm polytetrafluoroethylene filter membrane, 13 mm in diameter, Tianjin Jinteng Experimental Equipment Co., Ltd.

[0067] In the present invention, the reagents used are:

[0068] Polyhexamethylene biguanide hydrochloride standard, purity 97.2%, purchased from Dr. Ehrenstorfer, Germany; hydrochloric acid (analytical grade), content 36% to 38%, density 1.19 g / mL, purchased from Dongguan Dongjiang Chemical Reagent Co., Ltd.; ammonium chloride (analytical grade), purchased from Sinopharm Chemical Reagent Co., Ltd.; ammonia water (HPLC grade), content ≥25%, density 0.91 g / mL, purchased from Shanghai Anpu Experimental Technology Co., Ltd.; phosphoric acid (HPLC grade), content 85%, density 1.69 g / mL, purchased from Shanghai Anpu Experimental Technology Co., Ltd.; acetonitrile (HPLC grade), purchased from Shanghai Anpu Experimental Technology Co., Ltd.

[0069] In the present invention, the solution used is prepared by the following method:

[0070] Ammonium chloride solution (1.8 mol / L, pH 1.8): Weigh 24.07 g of ammonium chloride, dissolve it in water and transfer it to a 250 mL volumetric flask, dilute to the mark. Transfer the above solution to a 500 mL beaker and adjust the pH to 1.8 with hydrochloric acid.

[0071] Extraction solution: Accurately transfer 100 mL of ammonium chloride solution into a 250 mL volumetric flask and dilute to the mark with methanol.

[0072] 0.1% phosphoric acid solution (volume fraction): Pipette 1.0 mL of phosphoric acid and dissolve it in 1000 mL of first-grade water.

[0073] Standard stock solution: Accurately weigh 100 mg (accurate to 0.1 mg) of polyhexamethylene biguanide hydrochloride standard, dilute with water and make up to 10 mL to obtain a polyhexamethylene biguanide hydrochloride stock solution with a mass concentration of 10000 mg / L.

[0074] Standard intermediate solution: Accurately transfer 0.5 mL of the standard stock solution into a 10 mL volumetric flask and dilute to the mark with the extraction solution to obtain a polyhexamethylene biguanide hydrochloride standard intermediate solution with a mass concentration of 500 mg / L.

[0075] In the present invention, the test sample (positive sample) used is:

[0076] The positive samples for the extraction condition optimization experiment were prepared using commercially available textiles that were tested to be PHMB-free as the substrate. Natural plant fibers (represented by cotton and ramie), natural animal fibers (represented by mulberry silk), and artificial fibers (represented by polyester) were selected as the substrates. Four positive samples with different PHMB content levels were prepared by the immersion-baking method, among which sample 1# was cotton, sample 2# was ramie, sample 3# was mulberry silk, and sample 4# was polyester. The prepared positive samples were cut into pieces of about 5mm×5mm, mixed, and set aside.

[0077] Example 1: Determination of sample pretreatment conditions and chromatographic detection conditions

[0078] The method for detecting the content of polyhexamethylene biguanide hydrochloride in textiles is as follows.

[0079] 1.1 Selection of extraction method

[0080] The main extraction methods for detecting the residual amount of textile finishing agents include: Soxhlet extraction, solid-liquid oscillation extraction, ultrasonic extraction, microwave extraction, accelerated solvent extraction, etc. Among them, Soxhlet extraction is time-consuming and labor-intensive, and is gradually not used at present; accelerated solvent extraction is not widely used due to its expensive equipment. Compared with microwave extraction technology, ultrasonic extraction is simpler to operate. Therefore, in order to strive for the popularization and operability of the method standard, this application adopts ultrasonic extraction.

[0081] 1.2 Optimization of ultrasonic extraction conditions

[0082] The efficiency of ultrasonic extraction depends on five factors, including extraction method, type of extraction solvent, extraction time, extraction temperature, and extraction solvent volume. Therefore, this experiment will investigate the above five factors.

[0083] (1) Selection of extraction solvent

[0084] 1.2.1 Extraction effect of different extraction solvents

[0085] Polyhexamethylene biguanide hydrochloride is easily soluble in water and slightly soluble in low-grade alcohol organic solvents. Therefore, water, methanol, ethanol, isopropanol, and acetonitrile were used to extract positive samples of cotton, linen, silk, and polyester. Weigh 1g of positive samples of cotton, linen, silk, and polyester, respectively, add 20mL of water, methanol, ethanol, ethanol, isopropanol, and acetonitrile, respectively, and ultrasonically extract at 60°C for 30min. The extraction results are shown in Table 1. As can be seen from Table 1, different extraction solvents have a greater difference in the extraction effect on positive samples of cotton, linen, silk, and polyester. Among them, water has the best extraction effect on positive samples of cotton, linen, and silk, and methanol and ethanol have the best extraction effect on positive samples of polyester. The positive samples extracted with water, methanol, and ethanol were filtered, and the residues were further extracted with the corresponding water, methanol, and ethanol for the second and third time. The results showed that a high content of PHMB could be extracted, indicating that it is difficult for water, methanol, and ethanol to completely extract PHMB. By consulting the literature, it is found that cotton, linen, silk, and polyester contain more anions, and PHMB, as a biguanide cationic surfactant, ionizes in an aqueous solution under neutral conditions to form cationic groups, which form a strong binding force with the anions in cotton, linen, silk, and polyester, making it difficult to completely extract PHMB. As the pH of the solution decreases, the ionization of PHMB will be inhibited, and the strong binding force with the anions in cotton, linen, silk, and polyester will also be reduced. Therefore, the experiment selected hydrochloric acid solution with a pH value of 2.2 and 1 mol / L ammonium chloride solution (hydrochloric acid adjusted to pH 2.2) as the extraction solution, respectively. The results showed that the extraction effect of hydrochloric acid solution and ammonium chloride solution was significantly enhanced. For cotton, linen, and polyester positive samples, ammonium chloride solution had the best extraction effect; for silk positive samples, hydrochloric acid solution had the best extraction effect. The results are shown in Table 1.

[0086] Table 1 Extraction effect of different extraction solvents on PHMB in positive samples

[0087]

[0088] 1.2.2 Effect of volume fraction of ammonium chloride solution in the extraction solution

[0089] The experiment gave priority to using hydrochloric acid solution as the extraction solution. When the concentration of hydrochloric acid solution was 2.0 mol / L, the extraction effect was the best. A good recovery rate could be obtained in the spike recovery experiment. However, after the extraction solvent was directly applied to the machine, the baseline fluctuated greatly and the impurity peaks increased. Considering that the minimum pH value of the chromatographic column was 2.0, it was necessary to use ammonia water to adjust the pH value before the measurement on the machine. The operation process was relatively cumbersome, so the experiment considered using ammonium chloride solution as the extraction solution. Considering that the extraction effect of 1 mol / L ammonium chloride solution on silk-positive samples was poor, it was found through experiments that when a mixed solution of ammonium chloride solution and methanol was used as the extraction solution, the extraction effect on silk-positive samples was significantly enhanced. 0, 10, 20, 30, 40, 50, 60, 70, 80, 90 mL of 1 mol / L ammonium chloride solution (pH adjusted to 2.2 with hydrochloric acid) were taken respectively, and the volume was adjusted to 100 mL with methanol to obtain an ammonium chloride solution-methanol extraction solution with a volume fraction of 0% to 90% of the ammonium chloride solution. 20 mL of this solution was used to extract 1 g of cotton, linen, silk, and polyester positive samples respectively. The extraction effect was shown in Table 1. Figure 1 .from Figure 1 It can be seen that for cotton, linen, and silk positive samples, as the volume fraction of ammonium chloride solution increases, the PHMB peak area shows a trend of first increasing, then tending to equilibrium, and then decreasing; for cotton positive samples, the best extraction effect is achieved when the volume fraction of ammonium chloride solution is 50%, and for linen and silk positive samples, the best extraction effect is achieved when the volume fraction of ammonium chloride solution is 40%. For polyester positive samples, when the volume fraction of ammonium chloride solution increases from 0% to 30%, the peak area gradually increases, and the peak area does not change significantly when the volume fraction of ammonium chloride solution is further increased to 90%. Comprehensively considering the volume fraction of ammonium chloride solution in the ammonium chloride solution-methanol extraction solution on the extraction effect of PHMB in cotton, linen, silk, and polyester positive samples, the volume fraction of ammonium chloride solution was finally selected as 40%.

[0090] 1.2.3 Effect of ammonium chloride concentration in the extraction solution on the extraction effect

[0091] In order to investigate the extraction effect of ammonium chloride solution concentration on PHMB in positive samples, the experiment prepared 0.0mol / L, 0.2mol / L, 0.4mol / L, 0.6mol / L, 0.8mol / L, 1.0mol / L, 1.2mol / L, 1.4mol / L, 1.6mol / L, 1.8mol / L, and 2.0mol / L ammonium chloride solutions, and adjusted the pH value to 2.2 with hydrochloric acid. 40mL of the above solutions were respectively taken and the volume was adjusted to 100mL with methanol to obtain ammonium chloride solution-methanol extraction solution. Figure 2 The concentration of ammonium chloride solution in the ammonium chloride solution-methanol extraction solution is given to determine the extraction effect of positive samples. Figure 2It can be seen that for cotton and linen positive samples, when the concentration of ammonium chloride increases from 0.0mol / L to 0.2mol / L, the peak area of ​​PHMB gradually increases. When the concentration of ammonium chloride is further increased to 2.0mol / L, the peak area of ​​PHMB does not change significantly. For silk positive samples, when the concentration of ammonium chloride increases from 0.0mol / L to 1.8mol / L, the peak area of ​​PHMB gradually increases. When the concentration of ammonium chloride is further increased to 2.0mol / L, the peak area of ​​PHMB does not change significantly. For polyester positive samples, when the concentration of ammonium chloride increases from 0.0mol / L to 2.0mol / L, the peak area of ​​PHMB does not change significantly. Therefore, the concentration of ammonium chloride was finally selected as 1.8mol / L in the experiment.

[0092] 1.2.4 Effect of pH value of ammonium chloride solution in the extraction solution on the extraction effect

[0093] The general extraction method does not examine the influence of pH value. The inventors have examined and confirmed that there are uncertain factors in the effect of pH value on the extraction effect. Therefore, under the optimized conditions of Sections 1.2.2 and 1.2.3, the pH value of the ammonium chloride solution in the extraction solution was examined for the effect of the extraction of PHMB in the positive samples.

[0094] In the experiment, 1.8 mol / L ammonium chloride solution was selected, and the pH value was adjusted to 4.6, 3.6, 2.6, 2.4, 2.2, 2.0, 1.8, and 1.6 with hydrochloric acid. 40 mL of the above solution was taken respectively, and the volume was adjusted to 100 mL with methanol to obtain ammonium chloride solution-methanol extraction solution. Figure 3 The extraction effects of ammonium chloride solutions with different pH values ​​on positive samples are given. Figure 3It can be seen that when the pH value of the ammonium chloride solution decreases from 4.6 to 3.6, the peak area of ​​PHMB in the cotton-positive sample gradually increases. When the pH value is further reduced to 2.4, the peak area of ​​PHMB does not change significantly. When the pH value is reduced from 2.4 to 2.0, the peak area of ​​PHMB will gradually increase again; when the pH value is further reduced, the peak area does not change significantly. When the pH value of ammonium chloride decreases from 4.6 to 2.4, the peak area of ​​PHMB in the hemp-positive sample does not change significantly. When the pH value is reduced from 2.4 to 1.8, the peak area of ​​PHMB gradually increases. When the pH value is further reduced, the peak area does not change significantly. When the pH value of ammonium chloride decreases from 4.6 to 1.8, the peak area of ​​PHMB in the silk-positive sample gradually increases. When the pH value is further reduced, the peak area does not change significantly. When the pH value of ammonium chloride in the polyester positive sample decreased from 4.6 to 2.0, the peak area of ​​PHMB did not change significantly. When the pH value continued to decrease to 1.8, the peak area gradually increased. When the pH value continued to decrease, the peak area of ​​PHMB did not change significantly. From this analysis, it can be seen that for this technology, pH has a certain effect on extraction. In summary, the pH value of the ammonium chloride solution was finally selected as 1.8 in the experiment.

[0095] 1.2.5 Selection of final extraction solution

[0096] Through the above experiments, an ammonium chloride solution-methanol mixed solution was finally selected as the extraction solution, wherein the concentration of the ammonium chloride solution was 1.8 mol / L (pH was adjusted to 1.8 with hydrochloric acid), and the volume fraction of the ammonium chloride solution was 40%.

[0097] (2) Selection of extraction time

[0098] Weigh 1.0g of cotton, linen, silk and polyester positive samples respectively, put them into a stoppered sealed glass extractor, add 20mL of extraction solution respectively, and perform single ultrasonic extraction at 50℃. After the extract is filtered through a 0.45μm polytetrafluoroethylene filter membrane, it is tested according to the instrument working conditions to investigate the effect of different extraction times on the extraction effect. The results are shown in Figure 4 .from Figure 4It can be seen that for hemp and silk positive samples, the peak area of ​​PHMB shows a trend of gradual increase with the increase of extraction time, and the peak area is the largest when the extraction time is 50min. The peak area does not change much when the extraction time continues to increase. For cotton positive samples, when the extraction time increases from 5min to 20min, the peak area of ​​PHMB shows a trend of gradual increase, and the peak area does not change much when the extraction time continues to increase. For polyester positive samples, when the extraction time increases from 5min to 10min, the peak area of ​​PHMB shows a trend of gradual increase, and the peak area does not change significantly when the extraction time continues to increase. Taking all factors into consideration, when the effect of extraction time on the extraction amount is examined alone, the optimal extraction time is 50min.

[0099] (3) Selection of extraction temperature

[0100] Weigh 1.0g cotton, 1.0g hemp, 1.0g silk, and 1.0g polyester positive samples respectively, put them into a stoppered sealed glass extractor, add 20mL of extraction solution respectively, select the extraction time as 50min, and investigate the effect of different extraction temperatures on the extraction effect. The results are shown in the figure. Figure 5 .from Figure 5 It can be seen that with the increase of extraction temperature, the peak area of ​​PHMB shows a trend of gradual increase. For cotton, linen and silk positive samples, when the extraction temperature is 70℃, the peak area of ​​PHMB reaches the maximum value. For polyester positive samples, when the extraction temperature is 50℃, the peak area reaches the maximum value. When the extraction temperature is further increased, the peak area does not increase significantly. Taking comprehensive considerations, when the effect of extraction temperature on the extraction amount is examined alone, the optimal extraction temperature is 70℃.

[0101] (4) Selection of ultrasonic extraction volume

[0102] Weigh a series of 1.0g positive samples (cotton, hemp, silk, polyester) respectively, put them into a stoppered sealed glass extractor, add 15mL, 20mL, 25mL, 30mL of extraction solution respectively, and perform single ultrasonic extraction for 50min at 70℃. The extract was filtered through a 0.45μm polytetrafluoroethylene filter membrane and tested according to the instrument working conditions. The results are shown in Table 2. As can be seen from Table 2, for cotton and silk positive samples, the optimal extraction solvent volume is 20mL; for hemp positive samples, the optimal extraction volume is 25mL, and for polyester positive samples, the optimal extraction solvent volume is 15mL. Considering comprehensively, when the extraction solution volume is 20mL, each positive sample can obtain a good extraction effect, so the volume of the extraction solvent is selected to be 20mL. The results are shown in Table 2.

[0103] Table 2 Effect of extraction solvent volume on the extraction of PHMB in positive samples

[0104]

[0105] (5) Selection of extraction times

[0106] Positive samples of cotton, linen, silk and polyester were taken and placed in 50mL stoppered glass extractors. 20mL of extracting solution was added respectively. The extraction temperature was 70℃ and the extraction time was 50min. After each extraction, the extracting solution was filtered through a 0.45μm polytetrafluoroethylene filter membrane and tested according to the instrument working conditions. The extraction volume of each time was measured, and the total extraction volume and the percentage of each extraction volume in the total extraction volume were calculated. The results are shown in Table 3. For positive samples of cotton, linen, silk and polyester, the first extraction volume accounted for more than 92% of the total extraction volume. In order to improve the detection efficiency, one ultrasonic extraction method was finally used. The results are shown in Table 3.

[0107] Table 3 Results of continuous ultrasonic extraction experiments / mg / g

[0108]

[0109] (6) Selection of filter membrane

[0110] The experiment selected nylon filter membranes, polyethersulfone filter membranes, cellulose acetate filter membranes, and polytetrafluoroethylene filter membranes from different manufacturers, and tested them with a 10 mg / L standard solution. The results showed that most filter membranes had an adsorption effect on PHMB, resulting in a low recovery rate. Filter membranes of the same material from different manufacturers have different adsorption effects on PHMB. Through repeated tests, the polytetrafluoroethylene filter membrane produced by Tianjin Jinteng Experimental Equipment Co., Ltd. was used to filter the PHMB solution, and the recovery rate was the best. Therefore, the Jinteng polytetrafluoroethylene filter membrane was selected.

[0111] (7) Confirmation of final extraction conditions

[0112] In summary, the final pretreatment conditions are: take a representative sample, cut it into pieces of about 5mm×5mm, and mix it. Accurately weigh 1.0g of the above sample, accurate to 0.01g, place it in a 50mL stoppered glass extractor, accurately add 20mL of extracting solution, place it in an ultrasonic extractor, ultrasonically extract at 70℃ for 50min, cool to room temperature, filter through a 0.45μm polytetrafluoroethylene filter membrane, and test according to the instrument working conditions. If necessary, dilute appropriately before analysis.

[0113] 1.3 Optimization of chromatographic conditions

[0114] (1) Selection of detection wavelength

[0115] Test the UV-visible spectrum of PHMB standard solution, such as Figure 6 As shown, there is a strong absorption peak at 236 nm, so the detection wavelength is selected as 236 nm.

[0116] (2) Selection of chromatographic column

[0117] By consulting the literature, polyhexamethylene biguanide hydrochloride was determined by high performance liquid chromatography, and the main chromatographic columns used were C18 liquid chromatography columns and cyano columns. Therefore, this experiment first selected C18 liquid chromatography columns and cyano columns for testing. The results showed that when using C18 liquid chromatography columns of different specifications and models, either the elution time of PHMB was earlier (peaking near the solvent peak) or multiple peaks would appear, affecting the qualitative and quantitative analysis of PHMB. When a cyano column was used as the analytical column, a chromatographic peak of PHMB peak could be obtained by controlling the proportion and pH value of the mobile phase. At the same time, the experiment also used a variety of other liquid chromatography columns for testing, such as phenyl columns, amino columns, etc., and the test results were not ideal. The experiment investigated three different specifications of cyano chromatographic columns: 250mm (column length) × 4.6mm (inner diameter) × 5μm (particle size), 150mm (column length) × 4.6mm (inner diameter) × 5μm (particle size), and 75mm (column length) × 4.6mm (inner diameter) × 3.5μm (particle size). The peak appearance of the chromatographic peak was investigated by adjusting different mobile phases, proportions, and pH values. The results showed that when a 250mm chromatographic column was used, the chromatographic peak shape was relatively poor; while when a 150mm or 75mm chromatographic column was used, a complete chromatographic peak could be obtained. The shorter the column, the earlier the peak appearance time. By comparison, it was found that when a 150mm chromatographic column was used, the chromatographic peak response value of PHMB was higher. Therefore, the experiment finally selected a cyano chromatographic column of 150mm (column length) × 4.6mm (inner diameter) × 5μm (particle size) as the analytical column.

[0118] (3) Selection of mobile phase

[0119] In reversed-phase liquid chromatography, highly polar mobile phases such as water, methanol, and acetonitrile are generally used. In this experiment, methanol / water and acetonitrile / water were first selected as mobile phases, and it was found that the chromatographic peak of PHMB could not be obtained. In the literature, acetonitrile, water, and 3mmol / L hydrochloric acid solution were used as mobile phases. Acetonitrile and water were used to wash the chromatographic column in the early stage, so that the guanidine cation of PHMB formed a strong interaction with the polar bonding groups in the cyano column. When the mobile phase transitioned to acetonitrile-hydrochloric acid solution, the ionization of PHMB would be suppressed, and the strong binding force with the polar bonding groups in the cyano column would also be reduced. Therefore, a chromatographic peak of PHMB was obtained. However, using hydrochloric acid solution as the mobile phase may damage the metal components of the instrument. Therefore, this experiment used organic acid phosphoric acid aqueous solution instead of inorganic acid solution, and investigated the chromatographic peak of PHMB when acetonitrile, water, phosphoric acid solution and methanol, water, and phosphoric acid aqueous solution were used as mobile phases. Through experiments, it was found that one PHMB chromatographic peak can be obtained by using the above mobile phases. When methanol, water, and phosphoric acid aqueous solution are used, the column pressure is large, and the baseline fluctuates greatly when the mobile phase is switched; while when acetonitrile, water, and phosphoric acid solution are used as mobile phases, the column pressure is small, and the baseline fluctuates less when the mobile phase is switched. Therefore, acetonitrile, water, and phosphoric acid solution are selected as mobile phases in this experiment.

[0120] The effect of different volume fractions of phosphoric acid-water solution on the chromatographic peak of PHMB was investigated. Phosphoric acid-water solutions with volume fractions of 0.2‰, 0.4‰, 0.6‰, 0.8‰, 1.0‰, and 1.2‰ were used as mobile phases to investigate the changes in the PHMB peak area. Figure 7 .from Figure 7 It can be seen that with the increase of phosphoric acid volume fraction, the peak area of ​​PHMB gradually increases. When the volume fraction of phosphoric acid is 1.0‰, the peak area of ​​PHMB reaches the maximum value. If the volume fraction of phosphoric acid is further increased, the peak area of ​​PHMB does not change much. Therefore, the volume fraction of phosphoric acid is selected as 1.0‰.

[0121] (4) Selection of flow rate

[0122] When other chromatographic conditions remain unchanged, changing the flow rate will affect the retention time, peak area, separation and column pressure of the analyte. When the column temperature is 30°C, the retention time, peak area, separation and column pressure of PHMB are investigated at flow rates of 0.8mL / min, 1.0mL / min, 1.2mL / min and 1.5mL / min. The experiment shows that when the flow rate is 1.0mL / min, the column pressure is moderate, the peak area response is good, and the retention time and separation are within a reasonable range.

[0123] (5) Selection of column temperature

[0124] After the flow rate is determined, the column temperature is changed to 25, 30, 35, 40, 45, and 50°C. The test results show that with the increase of temperature, the overall peak area does not change much, and the column pressure continues to decrease with the increase of temperature, but the retention time does not change significantly with the change of column temperature. When the temperature of the chromatographic column is 30°C, the column pressure is appropriate and the peak shape of the target chromatographic peak is the best, so the column temperature is selected to be 30°C.

[0125] (6) Determination of chromatographic conditions

[0126] Under the conditions of column temperature of 30°C and column flow rate of 1.0mL / min, the standard solution was gradient eluted, the initial composition of the mobile phase and the elution gradient were changed, and the changes in the PHMB peak were observed. The results showed that when the mobile phase was eluted with the elution gradient in Table 4, the chromatographic separation effect was the best, the target analyte was not interfered by impurities at all, and the signal intensity was large. Wherein mobile phase A: water, mobile phase B: 0.1% phosphoric acid aqueous solution (V / V), mobile phase C: acetonitrile.

[0127] Table 4 Mobile phase gradient elution program

[0128]

[0129]

[0130] Figure 8 This is the HPLC chart of PHMB standard solution. Figure 8 The PHMB chromatographic peak appears at retention time t R =16.523min, the peak is sharp, symmetrical, and not interfered by impurities.

[0131] This method is qualitative based on the retention time of the chromatographic peak, confirmed by combining its ultraviolet absorption spectrum, and quantitatively analyzed by external standard method based on the peak area of ​​the chromatographic peak.

[0132] Therefore, the chromatographic separation conditions finally determined were: gradient elution with the mobile phase in Table 4, a flow rate of 1.0 mL / min, a column temperature of 35° C., and monitoring with a DAD detector.

[0133] Example 2: Linear range and detection limit

[0134] Accurately weigh 0.1g PHMB standard (precision 0.1mg), and use pure water to prepare a PHMB standard stock solution with a mass concentration of 10000μg / mL. Accurately transfer 1.0mL PHMB standard stock solution and dilute it to a 10mL volumetric flask with the extract to obtain a standard intermediate solution with a mass concentration of 1000μg / mL. Use the extract to dilute the standard intermediate solution step by step to obtain a series of standard working solutions with mass concentrations of 10, 20, 50, 100, and 200μg / mL. Test the series of standard working solutions under the optimized chromatographic conditions. Plot the mass concentration using the peak area minus the blank solution. The results show that when the mass concentration is 10-200μg / mL, the linear relationship is good, the linear equation is Y=9536.8x-710.13, and the linear correlation coefficient R 2 =0.9999. The detection limit of the instrument was calculated with a 3-fold signal-to-noise ratio (S / N=3), and the detection limit of the method was 60 mg / kg. The quantification limit of the instrument was calculated with a 10-fold signal-to-noise ratio (S / N=10), and the quantification limit of the method was 200 mg / kg.

[0135] Example 3: Recovery and precision test

[0136] 1.0 g of cotton, ramie, mulberry silk and polyester without target compounds were weighed, and 0.2 mg, 1.0 mg and 2.0 mg of PHMB were added, respectively. Seven parallel samples were prepared for each level and tested according to the above method. The results are shown in Table 5. The average recovery rate of the method was calculated based on the data in Table 5, and the results are shown in Table 6. The average recovery rate of PHMB was 90.1% to 100.0%, and the relative standard deviation was 1.09% to 4.31%.

[0137] Table 5 Addition recovery rate experiment of different matrix textiles

[0138]

[0139]

[0140] Table 6 Recovery and precision of different matrix textiles at different addition levels

[0141]

[0142]

[0143] Example 4: Sample testing

[0144] The method established in this project was used to determine the commercially available underwear, panties, socks, sports masks and other textiles. Polyhexamethylene biguanide hydrochloride was detected in the lining fabric of a sports mask, with a content of 1.42 mg / g. Fig. 9The high performance liquid chromatogram of the positive sample is shown in Figure 2.

[0145] in conclusion:

[0146] In summary, this method is simple and easy to operate. From the experimental results, the linear relationship, precision and recovery rate of this method all meet the requirements of qualitative and quantitative analysis, and can meet the needs of polyhexamethylene biguanide hydrochloride detection in textiles.

[0147] The above-mentioned embodiments only express the implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A method for detecting polyhexamethylene biguanide hydrochloride in textiles, characterized in that: The following steps are involved: (1) Sample pretreatment: Add the textile to be tested into the extraction solvent for ultrasonic extraction and filter to obtain the sample test solution; (2) High performance liquid chromatography detection: analyzing the sample test solution according to the following chromatographic conditions to obtain a chromatogram, and determining the content of polyhexamethylene biguanide hydrochloride in the textile by analytical calculation based on the chromatogram; Wherein, the extraction solvent in step (1) is composed of ammonium chloride solution and methanol, the volume fraction of the ammonium chloride solution is 20% to 70%, the concentration is 0.5 mol / L to 2.0 mol / L, and the pH value is 1.5 to 4.0; The chromatographic conditions in step (2) include: Chromatographic column: C18 liquid chromatography column or cyano chromatography column, 4.6×150mm, 5μm or 4.6×75mm, 3.5μm, Column temperature: 30℃~50℃, Mobile phase A: water, Mobile phase B: phosphoric acid aqueous solution, volume fraction 0.1‰~1.2‰, Mobile phase C: acetonitrile, Flow rate: 0.8mL / min~1.2mL / min, The elution gradient is: 0min~1min, mobile phase A: 94%, mobile phase B: 1%, mobile phase C: 5%; 1min~12min, mobile phase A: 59%, mobile phase B: 1%, mobile phase C: 40%; 12min~20min, mobile phase A: 0%, mobile phase B: 60%, mobile phase C: 40%; 20min~27min, mobile phase A: 94%, mobile phase B: 1%, mobile phase C: 5%; Running time: 27 minutes.

2. The method for detecting polyhexamethylene biguanide hydrochloride in textiles according to claim 1, characterized in that: The extraction solvent in step (1) consists of ammonium chloride solution and methanol, the volume fraction of the ammonium chloride solution is 40%, the concentration is 1.8 mol / L, and the pH value is 1.

8.

3. The method for detecting polyhexamethylene biguanide hydrochloride in textiles according to claim 1, characterized in that: The ultrasonic extraction in step (1) adopts a single ultrasonic extraction method.

4. The method for detecting polyhexamethylene biguanide hydrochloride in textiles according to claim 1, characterized in that: In step (1), the mass ratio of the textile to be tested to the extraction solvent is 1:(15-25).

5. The method for detecting polyhexamethylene biguanide hydrochloride in textiles according to claim 1, characterized in that: The extraction time of the ultrasonic extraction in step (1) is 40 min to 60 min.

6. The method for detecting polyhexamethylene biguanide hydrochloride in textiles according to claim 1, characterized in that: The extraction temperature of the ultrasonic extraction in step (1) is 60°C to 80°C.

7. The method for detecting polyhexamethylene biguanide hydrochloride in textiles according to claim 1, characterized in that: The volume of the extraction solution for ultrasonic extraction in step (1) is 15 mL to 35 mL.

8. The method for detecting polyhexamethylene biguanide hydrochloride in textiles according to claim 1, characterized in that: The filter membrane used in the filtration in step (1) is selected from a polytetrafluoroethylene filter membrane with a pore size of 0.45 μm produced by Tianjin Jinteng Experimental Equipment Co., Ltd.

9. The method for detecting polyhexamethylene biguanide hydrochloride in textiles according to claim 1, characterized in that: The flow rate in step (2) is 1.0 mL / min.

10. The method for detecting polyhexamethylene biguanide hydrochloride in textiles according to claim 1, characterized in that: The chromatographic column in step (2) is a cyano chromatographic column, 4.6×150 mm, 5 μm.

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