Ultraviolet detection method for simultaneously detecting trace and trace benzyl quaternary ammonium salts

Abstract

The invention relates to an ultraviolet detection method for simultaneously detecting trace and trace benzyl quaternary ammonium salts. The method comprises the following steps: preparing trace and trace benzyl quaternary ammonium salt standard solutions; determining an ultraviolet detection wavelength; drawing a standard curve; and detecting the sample. The ultraviolet detection method provided by the invention avoids operation errors caused by a dilution or concentration step in the detection process of the sample to be detected, has the advantages of simplicity and convenience in operation, high analysis speed, good accuracy and the like, and can be used for simultaneously detecting trace and trace components.

Description

Technical Field

[0001] The invention relates to the technical field of content analysis and detection, and in particular to an ultraviolet detection method for simultaneously detecting micro and trace amounts of benzyl quaternary ammonium salt. Background Art

[0002] Benzyl quaternary ammonium salt is a type of quaternary ammonium salt type cationic surfactant, which is easily soluble in water and can form micelles in water. It has certain degreasing and decontamination capabilities. It can also destroy the integrity of cell membranes, has broad-spectrum, strong antibacterial activity and low toxic side effects. Therefore, as a preservative, antibacterial agent, and disinfectant, benzyl quaternary ammonium salt is widely used in medical treatment, daily cosmetics, textiles, water treatment and other fields. In addition, benzyl quaternary ammonium salt is also used as anion membrane material for fuel cells, with good ionic conductivity and alkaline stability, which prolongs the service life of the membrane.

[0003] The quantitative methods of benzyl quaternary ammonium salts are divided into chemical methods and instrumental methods. The commonly used chemical method is titration, which is suitable for macro-analysis, but has large errors and low accuracy for micro-analysis. Commonly used instrumental methods include organic solvent extraction-ultraviolet visible spectrophotometry, liquid chromatography, liquid chromatography-tandem mass spectrometry, matrix-assisted laser desorption ionization time-of-flight mass spectrometry, etc.

[0004] CN116223673A discloses a HS-GC-MS method for detecting benzyl chloride in benzylated quaternary ammonium salts, the method comprising the following steps: (1) sample pretreatment: dissolving the benzylated quaternary ammonium salt of the sample to be tested in ethanol to obtain a sample solution; (2) preparation of a standard solution: weighing a standard benzyl chloride, diluting it to a 25 mL volumetric flask with ethanol, and then preparing a standard working solution with a concentration gradient; (3) subjecting the standard working solution in step (2) to headspace-gas chromatography-mass spectrometry analysis: plotting a standard curve of benzyl chloride with the concentration of benzyl chloride as the abscissa and the measured peak area as the ordinate; subjecting the sample solution in step (1) to headspace-gas chromatography-mass spectrometry analysis, substituting the obtained peak area into the linear regression equation of the obtained standard curve, and obtaining the content of benzyl chloride in the sample to be tested.

[0005] CN114014798A discloses a method for detecting bipyridinium quaternary ammonium salt, which comprises the following steps: (1) measuring the ultraviolet maximum absorption wavelength of the bipyridinium quaternary ammonium salt sample to be tested by using an ultraviolet-visible spectrophotometer; (2) preparing bipyridinium quaternary ammonium salt standard samples of different concentrations, measuring the absorbance of the standard samples at the ultraviolet maximum absorption wavelength, and drawing a standard curve between concentration and absorbance; (3) measuring the absorbance of the sample to be tested by using an ultraviolet-visible spectrophotometer, and calculating the concentration of the bipyridinium quaternary ammonium salt according to the standard curve.

[0006] Organic solvent extraction is complicated to operate, with serious pollution and incomplete extraction; liquid chromatographs and mass spectrometers are expensive, complicated to operate, take a long time to detect, and have poor accuracy in testing trace and trace components; conventional ultraviolet or infrared spectroscopy only uses a single standard curve to detect the content of the sample to be tested, and there is a problem that the absorption wavelength does not match the content of the sample to be tested, the detection error is large or exceeds the detection limit, and the content of trace and trace components cannot be detected simultaneously. Especially for the determination of trace collectors, due to the low concentration, the detection exceeds the measurement range or is interfered by other substances, and the concentration method is prone to inaccurate measurement due to operational errors, and it is necessary to introduce additional operating steps, which is not conducive to the testing of large batches of samples. Therefore, it is necessary to invent a method that is fast, simple to operate, does not require the introduction of additional reagents or operating steps, is cheap, and can directly measure trace and trace reagents. Summary of the invention

[0007] In order to solve the above technical problems, the present invention provides a UV detection method for simultaneously detecting trace and micro amounts of benzyl quaternary ammonium salt. The UV detection method of the present invention has the advantages of being convenient and fast, not requiring dilution and concentration, having good accuracy, and realizing the simultaneous detection of trace and micro amounts of benzyl quaternary ammonium salt.

[0008] To achieve this object, the present invention adopts the following technical solutions:

[0009] The present invention provides an ultraviolet detection method for simultaneously detecting micro and trace amounts of benzyl quaternary ammonium salts, the method comprising the following steps:

[0010] (1) preparing a series of trace and micro-amounts of benzyl quaternary ammonium salt standard solutions;

[0011] (2) Determining the UV detection wavelength: Using a UV-visible spectrophotometer to perform spectral scanning on a series of trace and micro-amount benzyl quaternary ammonium salt standard solutions, determining the UV detection wavelength of trace and micro-amount benzyl quaternary ammonium salt;

[0012] (3) drawing a standard curve: using an ultraviolet-visible spectrophotometer to perform photometric measurement on the series of trace and trace benzyl quaternary ammonium salt standard solutions in step (1) at the ultraviolet detection wavelength described in step (2), and establishing standard curves between the concentration and absorbance of trace and trace benzyl quaternary ammonium salts, respectively;

[0013] (4) Testing the sample: using the UV-visible spectrophotometer described in step (3) to perform photometric measurement on the sample to be tested at the UV detection wavelength described in step (2), and then determining the content of the benzyl quaternary ammonium salt in the sample solution according to the standard curve drawn in step (3).

[0014] The ultraviolet detection method of the present invention adopts ultraviolet visible spectrophotometer to carry out full spectrum scanning with ultrapure water as background, comprehensively considers factors such as baseline, peak stability, sensitivity, detection limit, etc., selects the most suitable absorption wavelength as the detection wavelength of trace and trace detection according to the unique ultraviolet spectrum characteristics of benzyl quaternary ammonium salt, fixes different detection wavelengths to carry out the photometric determination of trace and trace solutions respectively, establishes the standard curve between the concentration and absorbance of trace and trace benzyl quaternary ammonium salt solution, measures the absorbance of the sample to be tested under different detection wavelengths, and calculates the benzyl quaternary ammonium salt content in the sample solution according to the standard curve. The method of the present invention has the advantages of simple operation, fast analysis speed, no need for dilution and concentration, high accuracy, simultaneous detection of trace and trace components, low cost, etc., and has broad application prospects.

[0015] As a preferred embodiment of the present invention, the step of configuring a series of trace and trace amounts of benzyl quaternary ammonium salt standard solutions in step (1) comprises:

[0016] Weigh the benzyl quaternary ammonium salt solid, dissolve the weighed benzyl quaternary ammonium salt solid in ultrapure water as solvent, and obtain a standard benzyl quaternary ammonium salt stock solution after constant volume. Take a series of volumes of the standard benzyl quaternary ammonium salt stock solution, dilute and constant volume to obtain a standard solution.

[0017] Preferably, the ultrapure water used has a water resistivity of 18.5 MΩ·cm.

[0018] Preferably, the concentration range of the series of trace benzyl quaternary ammonium salt standard solutions in step (1) is 5-100 ppm, for example, with a concentration gradient of 20 ppm, the concentration of the trace benzyl quaternary ammonium salt standard solution can be 20 ppm, 40 ppm, 60 ppm, 80 ppm, 100 ppm; or a non-isoconcentration gradient, the concentration of the trace benzyl quaternary ammonium salt standard solution can be 5 ppm, 10 ppm, 40 ppm, 60 ppm, 80 ppm, 100 ppm, etc., but is not limited to the listed values, and other unlisted values ​​within the above numerical range are equally applicable.

[0019] Preferably, the concentration range of the series of trace benzyl quaternary ammonium salt standard solutions in step (1) is 0.1-5ppm, for example, with a concentration gradient of 0.2ppm, the concentration of the trace benzyl quaternary ammonium salt standard solution can be 0.2ppm, 0.4ppm, 0.6ppm, 0.8ppm, 1ppm; or a non-isoconcentration gradient, the concentration of the trace benzyl quaternary ammonium salt standard solution can be 0.1ppm, 1ppm, 2ppm, 4ppm, 5ppm, etc., but is not limited to the listed values, and other unlisted values ​​within the above numerical range are equally applicable.

[0020] As a preferred technical solution of the present invention, the specific steps of the spectral scanning in step (2) include: using an ultraviolet-visible spectrophotometer, with ultrapure water as the background, to perform spectral scanning on a series of trace and trace benzyl quaternary ammonium salt standard solutions in the wavelength range of 185 to 800 nm.

[0021] Preferably, the ultraviolet detection wavelength range of the trace benzyl quaternary ammonium salt in step (2) is 200-220nm, for example 200nm, 205nm, 210nm, 215nm, 220nm, etc., but is not limited to the listed values, and other unlisted values ​​within the above numerical range are also applicable.

[0022] Further preferably, when detecting trace amounts of hexadecyldimethylbenzylammonium chloride, the ultraviolet detection wavelength is 216 nm; when detecting trace amounts of dodecyldimethylbenzylammonium chloride, the ultraviolet detection wavelength is 208.5 nm.

[0023] Preferably, the ultraviolet detection wavelength range of the trace benzyl quaternary ammonium salt in step (2) is 185-200nm, such as 185nm, 190nm, 195nm, 200nm, etc., but is not limited to the listed values, and other unlisted values ​​within the above numerical range are also applicable.

[0024] Further preferably, when detecting trace amounts of hexadecyldimethylbenzylammonium chloride, the ultraviolet detection wavelength is 192.5 nm; when detecting trace amounts of dodecyldimethylbenzylammonium chloride, the ultraviolet detection wavelength is 189.5 nm.

[0025] As is well known to those skilled in the art, when a series of trace and micro-amounts of benzyl quaternary ammonium salt standard solutions are spectrally scanned in the wavelength range of 185 to 800 nm using an ultraviolet spectrophotometer with ultrapure water as the background, the maximum absorption wavelength λ of the maximum absorption peak of benzyl quaternary ammonium salt is within the experimental concentration range. max In the wavelength range of 187-194nm, the second largest absorption peak λ max At 216nm, the B band absorption produced by the π→π* transition of the benzene ring is at 250~270nm.

[0026] When the concentration of benzyl quaternary ammonium salt is 5-100ppm, as the concentration increases, the maximum absorption peak red shifts and its λ max Moves toward the long-wave direction, the peak position is unstable, and the maximum absorption peak λ max It is not suitable as a detection wavelength; the three absorption peaks of the benzene ring at 257nm, 262.5nm, and 268.5nm are too weak, and the sensitivity is too low as a detection wavelength, the error is large, and the data confidence is low; the second largest absorption peak is stable, the sensitivity is high, and it is not easily affected by other interferences, so the second largest absorption peak λ maxThe value is most suitable as the UV detection wavelength for trace amounts of benzyl quaternary ammonium salts.

[0027] When the concentration of benzyl quaternary ammonium salt is 0.1-5ppm, the second largest absorption peak suitable as the ultraviolet detection wavelength of trace benzyl quaternary ammonium salt is not suitable for trace analysis due to its weak intensity. The maximum absorption peak, which is unstable in trace amounts, can peak stably with strong peak intensity and high sensitivity. Therefore, its maximum absorption peak is most suitable as the ultraviolet detection wavelength of trace benzyl quaternary ammonium salt.

[0028] As a preferred technical solution of the present invention, the R value of the standard curve between the concentration and absorbance of the trace benzyl quaternary ammonium salt established in step (3) is 2 Reach 0.999 and above.

[0029] The standard curve R between the concentration and absorbance of trace benzyl quaternary ammonium salt in the present invention 2 Reaching 0.999 or above indicates that the ultraviolet detection method of the present invention is feasible and can realize the simultaneous detection of trace and micro amounts of benzyl quaternary ammonium salt components.

[0030] As a preferred technical solution of the present invention, the sample to be tested in step (4) is a water sample containing a benzyl quaternary ammonium salt component.

[0031] Preferably, the water sample can be a sample to be tested prepared by the method for preparing the standard solution in step (1), or can be other water samples containing benzyl quaternary ammonium salt components. Only the solid components need to be filtered, and no additional dilution or concentration steps are required.

[0032] Preferably, the photometric determination in step (4) includes parallel measurement at least 3 times and taking the average value.

[0033] As a preferred technical solution of the present invention, the method comprises the following steps:

[0034] (1) preparing a series of trace and micro-amounts of benzyl quaternary ammonium salt standard solutions: weighing benzyl quaternary ammonium salt solid, dissolving the weighed benzyl quaternary ammonium salt solid in ultrapure water as a solvent, and obtaining a standard benzyl quaternary ammonium salt stock solution after constant volume, taking a series of volumes of the standard benzyl quaternary ammonium salt stock solution, diluting and constant volume, and obtaining a standard solution;

[0035] Wherein, the concentration range of the series of trace benzyl quaternary ammonium salt standard solutions is 5-100ppm; the concentration range of the series of trace benzyl quaternary ammonium salt standard solutions is 0.1-5ppm;

[0036] (2) Determine the UV detection wavelength: Use a UV-visible spectrophotometer, with ultrapure water as the background, to perform spectral scanning on a series of trace and micro-amount benzyl quaternary ammonium salt standard solutions in the wavelength range of 185 to 800 nm;

[0037] Wherein, the ultraviolet detection wavelength range of the trace benzyl quaternary ammonium salt is 200-220nm; the ultraviolet detection wavelength range of the trace benzyl quaternary ammonium salt is 185-200nm;

[0038] (3) Drawing a standard curve: Using an ultraviolet-visible spectrophotometer, a series of trace benzyl quaternary ammonium salt standard solutions were photometrically measured in the range of 200-220 nm, and a series of trace benzyl quaternary ammonium salt standard solutions were photometrically measured in the range of 185-200 nm, and standard curves between the concentration and absorbance of trace benzyl quaternary ammonium salt were established respectively;

[0039] The R value of the standard curve between the concentration and absorbance of the trace benzyl quaternary ammonium salt is 2 Reach 0.999 and above;

[0040] (4) Detecting the sample: Using an ultraviolet-visible spectrophotometer, perform photometric measurement on the sample containing the benzyl quaternary ammonium salt component within the ultraviolet detection wavelength range described in step (2), perform parallel measurement at least 3 times, take the average value, and then determine the content of the benzyl quaternary ammonium salt in the sample solution based on a standard curve between the concentration and absorbance of trace benzyl quaternary ammonium salt.

[0041] Compared with the prior art, the present invention has at least the following beneficial effects:

[0042] The invention provides an ultraviolet detection method for simultaneously detecting trace and micro amounts of benzyl quaternary ammonium salt, which avoids the operation error caused by the dilution or concentration step in the detection process of a sample to be detected, has the advantages of simple operation, fast analysis speed, good accuracy, etc., and can simultaneously detect trace and micro amounts of components. In addition, when detecting the concentrations of trace and micro amounts of benzyl quaternary ammonium salt, the invention respectively selects the most suitable absorption wavelength as the detection wavelength, thereby realizing the simultaneous detection of trace and micro amounts of benzyl quaternary ammonium salt components, and the sample to be detected does not require a complicated pretreatment process. The ultraviolet visible spectrophotometer used in the invention has low cost, and does not use organic reagents for extraction or color development in the operation process, is green and pollution-free, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is the UV spectrum of trace amounts of hexadecyldimethylbenzylammonium chloride.

[0044] Figure 2 Standard curve for trace and micro amounts of hexadecyldimethylbenzylammonium chloride.

[0045] Figure 3 This is the UV spectrum of trace and trace amounts of dodecyldimethylbenzylammonium chloride.

[0046] Figure 4 It is the standard curve for trace and micro amounts of dodecyldimethylbenzylammonium chloride. DETAILED DESCRIPTION

[0047] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and through specific implementation methods. However, the following examples are only simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0048] Instruments and working conditions

[0049] Instrument used: UV-2600i UV-visible spectrophotometer

[0050] Instrument working conditions: temperature 15-35℃, humidity 30-80%, power supply AC100V-240V, 50 / 60Hz, in a dim and quiet environment, avoid interference from sunlight and other strong light.

[0051] Example 1

[0052] This embodiment provides a UV detection method for simultaneously detecting trace amounts of benzyl quaternary ammonium salts, the method comprising the following steps:

[0053] (1) Prepare a series of trace and micro-amounts of benzyl quaternary ammonium salt standard solutions: Weigh 0.1000 g of hexadecyl dimethyl benzyl ammonium chloride solid using an analytical balance, dissolve the weighed hexadecyl dimethyl benzyl ammonium chloride solid in ultrapure water, transfer the solution to a 1000 mL volumetric flask, transfer the washing liquid used to clean the beaker and glass rod into the volumetric flask, add ultrapure water to the mark, shake well, and obtain a 1000 ppm hexadecyl dimethyl benzyl ammonium chloride standard stock solution. The ultrapure water used has a water resistivity of 18.5 MΩ·cm.

[0054] Take 0.5mL, 1mL, 2mL, 4mL, 6mL, 8mL, and 10mL of 1000ppm hexadecyl dimethyl benzyl ammonium chloride standard stock solution in a 100mL volumetric flask, add ultrapure water to dilute to the scale, and shake well. The concentrations of the prepared series of trace hexadecyl dimethyl benzyl ammonium chloride standard solutions are 5ppm, 10ppm, 20ppm, 40ppm, 60ppm, 80ppm, and 100ppm, respectively.

[0055] Take 1mL, 2mL, 4mL, 6mL, 8mL, and 10mL of 10ppm hexadecyl dimethyl benzyl ammonium chloride standard solution in a 100mL volumetric flask, add ultrapure water to dilute to the scale, and shake well. The concentrations of the prepared series of trace hexadecyl dimethyl benzyl ammonium chloride standard solutions are 0.1ppm, 0.2ppm, 0.4ppm, 0.6ppm, 0.8ppm, and 1ppm, respectively.

[0056] (2) Determine the UV detection wavelength: Use a UV-2600i UV-visible spectrophotometer and ultrapure water as the background to perform spectral scanning of a series of trace and micro-hexadecyldimethylbenzylammonium chloride standard solutions in the wavelength range of 185 to 800 nm. The UV spectrum is as follows: Figure 1 Considering the factors such as baseline, peak stability, sensitivity, and detection limit, 216 nm was selected as the UV detection wavelength for trace hexadecyl dimethyl benzyl ammonium chloride, and 192.5 nm was selected as the UV detection wavelength for trace hexadecyl dimethyl benzyl ammonium chloride.

[0057] (3) Drawing a standard curve: Using a UV-2600i ultraviolet-visible spectrophotometer, the photometric determination of a series of trace hexadecyldimethylbenzyl ammonium chloride standard solutions was performed at 216 nm, and the photometric determination of a series of trace hexadecyldimethylbenzyl ammonium chloride standard solutions was performed at 192.5 nm. The standard curves between the concentration and absorbance of trace and trace hexadecyldimethylbenzyl ammonium chloride were established respectively. The standard curves are shown in Table 1. Figure 2 shown.

[0058] (4) Sample detection: UV-2600i ultraviolet-visible spectrophotometer was used to detect the ultraviolet absorbance of the two samples at 216 nm and 192.5 nm, respectively. The measurements were performed three times in parallel and the average value was taken. The absorbance results are shown in Table 1. According to the standard curve between the concentration and absorbance of trace hexadecyldimethylbenzyl ammonium chloride, the concentration of hexadecyldimethylbenzyl ammonium chloride in the sample was calculated to be 5.34×10 -7 g / mL and 1.51×10 -5 g / mL.

[0059] Table 1 Absorbance values ​​of hexadecyl dimethyl benzyl ammonium chloride in the samples to be tested

[0060]

[0061] from Figure 1 It can be seen that within the experimental concentration range, the maximum absorption wavelength λ of the maximum absorption peak of hexadecyl dimethyl benzyl ammonium chloride max In the wavelength range of 187-194nm, the second largest absorption peak λ max At 216nm, the B band absorption produced by the π→π* transition of the benzene ring is at 250~270nm.

[0062] When the concentration of hexadecyl dimethyl benzyl ammonium chloride is 5-100ppm, as the concentration increases, the maximum absorption peak red shifts and its λ max Moves toward the long-wave direction, the peak position is unstable, and the maximum absorption peak λ maxIt is not suitable as a detection wavelength; the three absorption peaks of the benzene ring at 257nm, 262.5nm, and 268.5nm are too weak, and the sensitivity is too low as a detection wavelength, the error is large, and the data confidence is low; the second largest absorption peak is stable at 216nm, with high sensitivity and is not easily affected by other interferences, so the second largest absorption peak λ max The value is most suitable as the UV detection wavelength for trace amounts of hexadecyldimethylbenzylammonium chloride.

[0063] When the concentration of hexadecyldimethylbenzylammonium chloride is 0.1-1ppm, the second largest absorption peak suitable as the ultraviolet detection wavelength of trace hexadecyldimethylbenzylammonium chloride is not suitable for trace analysis due to its weak intensity. The maximum absorption peak, which is unstable in trace amounts, peaks stably at 192.5nm with strong peak intensity and high sensitivity. Therefore, 192.5nm is most suitable as the ultraviolet detection wavelength of trace hexadecyldimethylbenzylammonium chloride.

[0064] Depend on Figure 2 It can be seen that when the concentration is 0.1-1ppm, the standard curve of hexadecyl dimethyl benzyl ammonium chloride is y=568099.54x, and the determination coefficient R 2 is 0.99908; when the concentration is 5-100ppm, the standard curve of hexadecyl dimethyl benzyl ammonium chloride is y=19879.66x, and the determination coefficient R 2 The R of the two standard curves is 0.99998. 2 All of them reached 0.999 or above, indicating that the ultraviolet detection method of the present invention is feasible and can realize the simultaneous detection of trace and trace amounts of benzyl quaternary ammonium salt components.

[0065] Example 2

[0066] This embodiment provides a UV detection method for simultaneously detecting trace amounts of benzyl quaternary ammonium salts, the method comprising the following steps:

[0067] (1) Prepare a series of trace and micro-amounts of benzyl quaternary ammonium salt standard solutions: weigh 0.1000 g of dodecyl dimethyl benzyl ammonium chloride solid using an analytical balance, dissolve the weighed dodecyl dimethyl benzyl ammonium chloride solid in ultrapure water, transfer the solution to a 1000 mL volumetric flask, transfer the washing liquid used to clean the beaker and glass rod into the volumetric flask, add ultrapure water to the mark, shake well, and obtain a 1000 ppm dodecyl dimethyl benzyl ammonium chloride standard stock solution. The ultrapure water used has a water resistivity of 18.5 MΩ·cm.

[0068] Take 2mL, 4mL, 6mL, 8mL, and 10mL of 1000ppm dodecyl dimethyl benzyl ammonium chloride standard stock solution in a 100mL volumetric flask, add ultrapure water to dilute to the scale, and shake well. The concentrations of the prepared series of trace dodecyl dimethyl benzyl ammonium chloride standard solutions are 20ppm, 40ppm, 60ppm, 80ppm, and 100ppm, respectively.

[0069] Take 1mL, 2mL, 3mL, 4mL, and 5mL of 100ppm dodecyl dimethyl benzyl ammonium chloride standard solution in a 100mL volumetric flask, add ultrapure water to dilute to the scale, and shake well. The concentrations of the prepared series of trace dodecyl dimethyl benzyl ammonium chloride standard solutions are 1ppm, 2ppm, 3ppm, 4ppm, and 5ppm, respectively.

[0070] (2) Determine the UV detection wavelength: Use a UV-2600i UV-visible spectrophotometer and ultrapure water as the background to perform spectral scanning of a series of trace and trace dodecyl dimethyl benzyl ammonium chloride standard solutions in the wavelength range of 185 to 800 nm. The UV spectrum is as follows: Figure 3 Taking into account the factors such as baseline, peak stability, sensitivity, and detection limit, 208.5 nm was selected as the UV detection wavelength for trace dodecyl dimethyl benzyl ammonium chloride, and 189.5 nm was selected as the UV detection wavelength for trace dodecyl dimethyl benzyl ammonium chloride.

[0071] (3) Drawing a standard curve: Using a UV-2600i ultraviolet-visible spectrophotometer, the photometric determination of a series of trace dodecyl dimethyl benzyl ammonium chloride standard solutions was performed at 208.5 nm, and the photometric determination of a series of trace dodecyl dimethyl benzyl ammonium chloride standard solutions was performed at 189.5 nm. The standard curves between the concentration and absorbance of trace and trace dodecyl dimethyl benzyl ammonium chloride were established respectively. The standard curves are shown in Table 1. Figure 4 shown.

[0072] (4) Sample detection: UV-2600i ultraviolet-visible spectrophotometer was used to detect the ultraviolet absorbance of the two samples at 208.5 and 189.5 nm, respectively. The measurements were performed three times in parallel and the average value was taken. The absorbance results are shown in Table 2. According to the standard curve between the concentration and absorbance of trace dodecyl dimethyl benzyl ammonium chloride, the concentration of dodecyl dimethyl benzyl ammonium chloride in the sample was calculated to be 1.52×10 -6 g / mL and 5.63×10 -5 g / mL.

[0073] Table 2 Absorbance values ​​of dodecyl dimethyl benzyl ammonium chloride in the samples to be tested

[0074]

[0075]

[0076] Depend on Figure 4 It can be seen that when the concentration is 0.5-5ppm, the standard curve of dodecyl dimethyl benzyl ammonium chloride is y=133376.99x, and the determination coefficient R 2 is 0.99991; when the concentration is 5-100ppm, the standard curve of dodecyl dimethyl benzyl ammonium chloride is y=21510.66x, and the determination coefficient R 2 The R of the two standard curves is 0.99990. 2 All of them reached 0.999 or above, indicating that the ultraviolet detection method of the present invention is feasible and can realize the simultaneous detection of trace and trace amounts of benzyl quaternary ammonium salt components.

[0077] In summary, the present invention provides an ultraviolet detection method for simultaneously detecting trace and micro amounts of benzyl quaternary ammonium salts, and a full spectrum scan is performed using an ultraviolet-visible spectrophotometer with ultrapure water as a background, and the most suitable absorption wavelengths are selected as the detection wavelengths for trace and micro amounts of detection according to the unique ultraviolet spectrum characteristics of the benzyl quaternary ammonium salt in comprehensive consideration of factors such as baseline, peak stability, sensitivity, and detection limit, so that the trace and micro amounts of benzyl quaternary ammonium salt components can be simultaneously detected, and a complex pretreatment process is not required for the sample to be tested, and the operation error caused by the dilution or concentration step in the detection process of the sample to be tested is avoided, and the method has the advantages of simple operation, fast analysis speed, good accuracy, etc. At the same time, the ultraviolet-visible spectrophotometer used in the present invention has low cost, and no organic reagent is used for extraction or color development during the operation process, so the method is green and pollution-free, and has broad application prospects.

[0078] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A UV detection method for simultaneously detecting trace amounts of benzyl quaternary ammonium salts, characterized in that: The method comprises the following steps: (1) preparing a series of trace and micro-amounts of benzyl quaternary ammonium salt standard solutions; (2) Determining the UV detection wavelength: Using a UV-visible spectrophotometer to perform spectral scanning on a series of trace and micro-amount benzyl quaternary ammonium salt standard solutions, determining the UV detection wavelength of trace and micro-amount benzyl quaternary ammonium salt; (3) drawing a standard curve: using an ultraviolet-visible spectrophotometer to perform photometric measurement on the series of trace and trace benzyl quaternary ammonium salt standard solutions in step (1) at the ultraviolet detection wavelength described in step (2), and establishing standard curves between the concentration and absorbance of trace and trace benzyl quaternary ammonium salts, respectively; (4) Testing the sample: using the UV-visible spectrophotometer described in step (3) to perform photometric measurement on the sample to be tested at the UV detection wavelength described in step (2), and then determining the content of the benzyl quaternary ammonium salt in the sample to be tested based on the standard curve drawn in step (3).

2. The method according to claim 1, characterized in that: The step of preparing a series of trace and micro-amounts of benzyl quaternary ammonium salt standard solutions in step (1) comprises: Weigh the benzyl quaternary ammonium salt solid, dissolve the weighed benzyl quaternary ammonium salt solid in ultrapure water as solvent, and obtain a standard benzyl quaternary ammonium salt stock solution after constant volume. Take a series of volumes of the standard benzyl quaternary ammonium salt stock solution, dilute and constant volume to obtain a standard solution.

3. The method according to claim 1 or 2, characterized in that: The concentration range of the series of trace benzyl quaternary ammonium salt standard solutions in step (1) is 5-100 ppm; Preferably, the concentration range of the series of trace benzyl quaternary ammonium salt standard solutions in step (1) is 0.1-5 ppm.

4. The method according to any one of claims 1 to 3, characterized in that: The specific steps of the spectrum scanning in step (2) include: A UV-visible spectrophotometer was used to scan the spectra of a series of trace and micro-amount benzyl quaternary ammonium salt standard solutions in the wavelength range of 185-800 nm with ultrapure water as the background.

5. The method according to any one of claims 1 to 4, characterized in that: The ultraviolet detection wavelength range of the trace benzyl quaternary ammonium salt in step (2) is 200-220nm.

6. The method according to any one of claims 1 to 5, characterized in that: The ultraviolet detection wavelength range of the trace benzyl quaternary ammonium salt in step (2) is 185-200nm.

7. The method according to any one of claims 1 to 6, characterized in that: The R value of the standard curve between the concentration and absorbance of the trace benzyl quaternary ammonium salt established in step (3) is 2 Reach 0.999 and above.

8. The method according to any one of claims 1 to 7, characterized in that: The sample to be tested in step (4) is a water sample containing a benzyl quaternary ammonium salt component.

9. The method according to claims 1-8, characterized in that The photometric determination in step (4) includes parallel measurement at least 3 times and taking an average value.

10. The method according to any one of claims 1 to 9, characterized in that: The method comprises: (1) preparing a series of trace and micro-amounts of benzyl quaternary ammonium salt standard solutions: weighing benzyl quaternary ammonium salt solid, dissolving the weighed benzyl quaternary ammonium salt solid in ultrapure water as a solvent, and obtaining a standard benzyl quaternary ammonium salt stock solution after constant volume, taking a series of volumes of the standard benzyl quaternary ammonium salt stock solution, diluting and constant volume, and obtaining a standard solution; Wherein, the concentration range of the series of trace benzyl quaternary ammonium salt standard solutions is 5-100ppm; the concentration range of the series of trace benzyl quaternary ammonium salt standard solutions is 0.1-5ppm; (2) Determine the UV detection wavelength: Use a UV-visible spectrophotometer, with ultrapure water as the background, to perform spectral scanning on a series of trace and micro-amount benzyl quaternary ammonium salt standard solutions in the wavelength range of 185 to 800 nm; Wherein, the ultraviolet detection wavelength range of the trace benzyl quaternary ammonium salt is 200-220nm; the ultraviolet detection wavelength range of the trace benzyl quaternary ammonium salt is 185-200nm; (3) Drawing a standard curve: Using an ultraviolet-visible spectrophotometer, a series of trace benzyl quaternary ammonium salt standard solutions were photometrically measured in the range of 200-220 nm, and a series of trace benzyl quaternary ammonium salt standard solutions were photometrically measured in the range of 185-200 nm, and standard curves between the concentration and absorbance of trace benzyl quaternary ammonium salt were established respectively; The R value of the standard curve between the concentration and absorbance of the trace benzyl quaternary ammonium salt is 2 Reach 0.999 and above; (4) Detecting the sample: Using an ultraviolet-visible spectrophotometer, perform photometric measurement on the sample containing the benzyl quaternary ammonium salt component within the ultraviolet detection wavelength range described in step (2), perform parallel measurement at least 3 times, take the average value, and then determine the content of the benzyl quaternary ammonium salt in the sample solution based on a standard curve between the concentration and absorbance of trace benzyl quaternary ammonium salt.

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