Pretreatment method and device, method and system for determining saccharin sodium content in paper

Abstract

The present invention belongs to the field of detection and analysis, and specifically relates to a method for pre-treating paper containing sodium saccharin, comprising: (1) spraying a mixture of ethyl acetate and ethanol onto at least one surface of the paper containing sodium saccharin, and then immediately irradiating the surface with ultraviolet light of a wavelength of 200 to 400 nm; wherein the volume ratio of ethyl acetate to ethanol in the mixture is 1:(40 to 90); (2) drying the paper at 30 to 60° C.; optionally, cooling the dried paper; (3) allowing the dried or cooled paper to stand at 15 to 30° C. and 25% to 55% relative humidity to obtain pre-treated paper. The present invention also relates to a device for pre-treating paper containing sodium saccharin, and a method and system for determining the content of sodium saccharin in paper. The determination method of the present invention has high accuracy and reliability, does not require extraction operation, and can be implemented on site on a large scale.

Description

Technical Field

[0001] The invention belongs to the field of detection and analysis, and specifically relates to a method and a device for pre-treating paper containing saccharin sodium, and also relates to a method and a system for determining the content of saccharin sodium in paper. Background Art

[0002] In recent years, with the diversification of people's consumption, more and more paper products are added with sweeteners, such as cigarette tipping paper. Saccharin sodium has high sweetness, good stability and high cost performance, but excessive consumption of saccharin sodium will have adverse effects on human health. Therefore, many countries will limit the use of saccharin sodium, which requires the accurate determination of the saccharin sodium content in paper.

[0003] So far, liquid chromatography and liquid chromatography-mass spectrometry are generally used to determine the saccharin sodium content in paper. However, these methods require the use of chemical reagents to extract saccharin sodium before instrument detection. The extraction operation is cumbersome and large-scale detection cannot be carried out on site.

[0004] Therefore, there is an urgent need for a method for determining the content of saccharin sodium in paper that does not require extraction operations and can be operated on-site on a large scale. Summary of the invention

[0005] One of the purposes of the present invention is to provide a method for pre-treating paper containing sodium saccharin, so that the pre-treated paper can be subsequently detected by near-infrared diffuse reflectance spectroscopy to obtain the sodium saccharin content in the paper. The pre-treatment method does not require extraction operations and can be implemented on-site on a large scale. On this basis, another purpose of the present invention is to provide a method for determining the sodium saccharin content in paper, which has high accuracy and reliability. Another purpose of the present invention is to provide a device for pre-treating paper containing sodium saccharin. Another purpose of the present invention is to provide a system for determining the sodium saccharin content in paper.

[0006] The first aspect of the present invention relates to a method for pre-treating paper containing saccharin sodium, comprising the following steps:

[0007] (1) spraying a mixture of ethyl acetate and ethanol onto at least one surface of a paper containing saccharin sodium, and then immediately irradiating the surface with ultraviolet light having a wavelength of 200 to 400 nm (preferably a wavelength of 300 to 330 nm); wherein the volume ratio of ethyl acetate to ethanol in the mixture is 1:(40 to 90) (e.g., 1:45, 1:50, 1:65, 1:80, 1:85);

[0008] (2) drying the paper at 30°C to 60°C (e.g., 35°C, 40°C, 45°C, 50°C, 55°C); optionally, cooling the dried paper to 15°C to 28°C (e.g., 18°C, 20°C, 22°C, 25°C, 27°C, 28°C);

[0009] (3) The dried or cooled paper is allowed to stand at 15° C. to 30° C. (e.g., 18° C., 20° C., 22° C., 25° C., 26° C., 28° C., 29° C.) and 25% to 55% relative humidity (e.g., 30%, 35%, 40%, 45%, 50%, 53% relative humidity) to obtain pre-treated paper.

[0010] In some embodiments of the first aspect of the present invention, in step (1), the ultraviolet light irradiation time is 1 to 10 seconds, for example, 2, 3, 4, 5, 6, 7, 8, or 9 seconds.

[0011] In some embodiments of the first aspect of the present invention, the method has one or more of the following features A to I:

[0012] A. In step (1), the spraying amount of the mixed liquid is 1 to 30 ml / m 2 Paper, e.g. 2ml / m 2 Paper, 3ml / m 2 Paper, 4ml / m 2 Paper, 5ml / m 2 Paper, 7.5ml / m 2 Paper, 8ml / m 2 Paper, 10ml / m 2 Paper, 12ml / m 2 Paper, 15ml / m 2 Paper, 17ml / m 2 Paper, 20ml / m 2 Paper, 22ml / m 2 Paper, 25ml / m 2 Paper, 28ml / m 2 Paper, 29ml / m 2 Paper;

[0013] B. In step (2), the drying time is 1 to 40 seconds, for example, 2, 3, 5, 6, 7, 8, 9, 10, 13, 15, 17, 20, 22, 25, 27, 30, 35, 37 seconds;

[0014] C. In step (3), the standing time is 0.5 to 10 hours, for example 1, 1.5, 2, 3, 4, 5, 6, 7, 8, 9 hours;

[0015] D. In step (1), the mixed solution is sprayed onto two surfaces of the paper containing saccharin sodium;

[0016] E. In step (1), the mixed solution is sprayed using a spray box;

[0017] F. In step (1), ultraviolet light with a wavelength of 200 to 400 nm (e.g., a wavelength of 300 to 330 nm) is generated by an ultraviolet lamp;

[0018] Preferably, the operating voltage of the UV lamp is 3 to 5V;

[0019] G. In step (2), drying is performed using a hot plate;

[0020] H. in step (3), standing in a constant temperature and humidity chamber;

[0021] I. The paper is cigarette paper; preferably, the paper is selected from cigarette tipping paper, cigarette paper, filter rod forming paper and cigarette label paper, more preferably cigarette tipping paper.

[0022] In some embodiments of the first aspect of the present invention, in step (1), the mixed liquid is evenly sprayed onto at least one (eg, two) surfaces of the paper containing saccharin sodium.

[0023] The second aspect of the present invention relates to a method for determining the content of saccharin sodium in paper, comprising the following steps:

[0024] 1) Pre-treating paper containing saccharin sodium according to the method described in the first aspect of the present invention to obtain pre-treated paper;

[0025] 2) using near-infrared diffuse reflectance spectroscopy to detect the pretreated paper to obtain a detection spectrum; optionally, preprocessing the detection spectrum to obtain a preprocessed spectrum;

[0026] 3) Substituting the detected spectrum or the pre-processed spectrum into the quantitative model for calculation, the saccharin sodium content in the paper is obtained.

[0027] In some embodiments of the second aspect of the present invention, in step 3), the quantitative model is obtained by a method comprising the following steps:

[0028] (i) pre-treating a paper standard product with a known saccharin sodium content according to the method described in the first aspect of the present invention to obtain a pre-treated paper standard product;

[0029] (ii) detecting the pre-treated paper standard by near-infrared diffuse reflectance spectroscopy to obtain a standard spectrum; optionally, pre-processing the standard spectrum to obtain a pre-processed standard spectrum;

[0030] (iii) performing partial least squares regression on the standard spectrum or the pre-processed standard spectrum and the saccharin sodium content of the paper standard to obtain a quantitative model.

[0031] In some embodiments of the second aspect of the present invention, the method has one or more of the following a to h:

[0032] a. In step 2) and / or step (ii), the near-infrared diffuse reflectance spectroscopy acquisition wave number range is 15000 to 2000 cm -1 , preferably 10000~4000cm -1 ;

[0033] b. In step 2) and / or step (ii), the number of scans used in near-infrared diffuse reflectance spectroscopy is 40 to 80 times, for example 45 times, 50 times, 55 times, 60 times, 65 times, 68 times, 70 times, 75 times, 78 times;

[0034] c. In step 2) and / or step (ii), the resolution of near-infrared diffuse reflectance spectroscopy is 5 to 12 cm -1 , for example 7cm -1 、8cm -1 、10cm -1 、11cm -1 ;

[0035] d. In step 2) and / or step (ii), near-infrared diffuse reflectance spectroscopy is detected with an opaque white board as the background;

[0036] e. In step 2) and / or step (ii), the near-infrared diffuse reflectance spectroscopy is Fourier transform near-infrared diffuse reflectance spectroscopy;

[0037] f. Step 2) and / or step (ii), using TQ Analyst intelligent analysis software for preprocessing;

[0038] g. In step (iii), select 5299.43-4064.92cm from the standard spectrum or the preprocessed standard spectrum -1 The spectra in the wavenumber range were regressed with the sodium saccharin content of the paper standard using partial least squares method;

[0039] h. In step 3), the detection spectrum or pre-processed spectrum is 5299.43 to 4064.92 cm -1 The spectra in the wavenumber range are substituted into the quantitative model for calculation.

[0040] In some embodiments of the second aspect of the present invention, the near-infrared diffuse reflectance spectroscopy is a method of collecting spectra using a diffuse reflectance spectrum collection module in a near-infrared spectrometer;

[0041] Preferably, the near infrared spectrometer is a Fourier transform near infrared spectrometer.

[0042] In some embodiments of the second aspect of the present invention, in step 2) and / or step (ii), the preprocessing is selected from one or more of standard canonical transformation, first-order derivative, second-order derivative, vector normalization, multivariate signal correction and smoothed spectral processing (e.g., Norris filter smoothed spectral processing).

[0043] In some embodiments of the second aspect of the present invention, the paper in step 1) and the paper standard in step (i) are of the same brand of paper, preferably the same brand of cigarette paper, more preferably selected from the same brand of cigarette tipping paper, cigarette paper, filter rod forming paper and cigarette trademark paper, further preferably the same brand of cigarette tipping paper, and even more preferably the same brand of cigarette tipping paper from the same manufacturer.

[0044] In some embodiments of the second aspect of the present invention, in step (i), the saccharin sodium content of the paper standard is measured by the following steps:

[0045] (I) extracting the paper standard with water for 1 to 10 hours, separating the solid and the liquid, and obtaining a liquid phase;

[0046] (II) detecting the liquid phase using a high performance liquid chromatograph to obtain a detection result;

[0047] (III) Calculate the saccharin sodium content of the paper standard based on the test results.

[0048] In some embodiments of the second aspect of the present invention, in step (I), the extract is first extracted under static conditions for 1 to 2 hours, then extracted under ultrasonic conditions for 1 to 2 hours, and then extracted under static conditions for 1 to 2 hours.

[0049] In some embodiments of the second aspect of the present invention, in step (I), solid-liquid separation is performed by a microfiltration membrane.

[0050] In some embodiments of the second aspect of the present invention, in step (II), the operating conditions of the high performance liquid chromatography are one or more of the following A to E:

[0051] A. The chromatographic column is a C18 column; preferably, the chromatographic column specification is 250 mm×4.6 mm, 5 μm;

[0052] B. The mobile phase is methanol and ammonium acetate aqueous solution; preferably, methanol and ammonium acetate aqueous solution are eluted isocratically in a volume ratio of 5:95;

[0053] C. The flow rate of the mobile phase is 0.5 to 3 ml / min, for example, 1 ml / min;

[0054] D. The detection wavelength of the detector is 200-250nm (e.g. 230nm);

[0055] E. The injection volume is 10μl.

[0056] In some embodiments of the second aspect of the present invention, in step (III), the saccharin sodium content of the paper standard is calculated by external standard analysis.

[0057] The third aspect of the present invention relates to a device for pre-treating paper containing sodium saccharin, comprising a sprayer, an ultraviolet reactor, a dryer and a constant temperature and humidity controller; wherein:

[0058] The sprayer is provided with an inlet and an outlet, and a spray head is provided inside the sprayer for spraying a mixture of ethyl acetate and ethanol onto the paper containing saccharin sodium;

[0059] The ultraviolet reactor is provided with an inlet and an outlet, the inlet of the ultraviolet reactor is connected to the outlet of the sprayer, and an ultraviolet lamp is provided in the ultraviolet reactor for irradiating the sprayed paper with ultraviolet light;

[0060] The dryer is provided with an inlet and an outlet, the inlet of the dryer is connected to the outlet of the ultraviolet reactor, and a heating plate is provided in the dryer for drying the paper irradiated by ultraviolet light;

[0061] The thermostat and humidistat is provided with an inlet and an outlet, and the inlet of the thermostat and humidistat is connected with the outlet of the dryer, and is used for standing the dried paper under constant temperature and humidity conditions.

[0062] In some embodiments of the third aspect of the present invention, the nozzles in the sprinkler are arranged in a matrix.

[0063] In some embodiments of the third aspect of the present invention, the ultraviolet lamp in the ultraviolet reactor is tubular.

[0064] In some embodiments of the third aspect of the present invention, the heating plates are disposed on two opposite inner walls of the dryer.

[0065] In some embodiments of the third aspect of the present invention, the device also includes a conveying device, which includes a conveyor belt and a transmission wheel. The transmission wheel drives the conveyor belt to pass through the inlets and outlets of the four devices of the sprayer, the ultraviolet reactor, the dryer and the constant temperature and humidity controller for transmission, and the conveying device is used to transport paper.

[0066] In some embodiments of the third aspect of the present invention, the device further comprises a cooler, and the inlet of the thermostat and hygrostat is connected to the outlet of the dryer through the cooler.

[0067] In some embodiments of the third aspect of the present invention, a conveyor belt of the conveying device penetrates the cooler for conveying.

[0068] In some embodiments of the third aspect of the present invention, the cooler is provided with a cold air inlet and an exhaust gas outlet.

[0069] In some embodiments of the third aspect of the present invention, the mixture of ethyl acetate and ethanol is as described in the first aspect of the present invention.

[0070] In some embodiments of the third aspect of the present invention, the wavelength of the ultraviolet light is as described in the first aspect of the present invention.

[0071] In some embodiments of the third aspect of the present invention, the drying temperature and constant temperature and humidity conditions are as described in the first aspect of the present invention.

[0072] In some embodiments of the third aspect of the present invention, the cooling temperature is as described in the first aspect of the present invention.

[0073] The method described in the first aspect of the present invention is implemented by the device described in the third aspect of the present invention.

[0074] The fourth aspect of the present invention relates to a system for determining the sodium saccharin content in paper, comprising the device described in the third aspect of the present invention and a near-infrared diffuse reflectance spectrometer; wherein the near-infrared diffuse reflectance spectrometer is provided with an inlet and an outlet, and the inlet of the near-infrared diffuse reflectance spectrometer is connected to the outlet of the constant temperature and humidity controller.

[0075] In some embodiments of the fourth aspect of the present invention, a conveyor belt of the conveying device passes through the inlet and outlet of the near-infrared diffuse reflectance spectrometer for conveying.

[0076] In some implementations of the fourth aspect of the present invention, an opaque white board and an infrared probe are provided in the near-infrared diffuse reflectance spectrometer.

[0077] In some embodiments of the fourth aspect of the present invention, the near-infrared diffuse reflectance spectrometer is a Fourier transform near-infrared diffuse reflectance spectrometer.

[0078] In some embodiments of the fourth aspect of the present invention, the conditions of the near-infrared diffuse reflectance spectrometer are as described in the second aspect of the present invention.

[0079] In some implementations of the fourth aspect of the present invention, the near-infrared diffuse reflectance spectrometer may be a near-infrared spectrometer using a diffuse reflectance spectrum sampling module.

[0080] The method described in the second aspect of the present invention is implemented by the system described in the fourth aspect of the present invention.

[0081] Beneficial effects achieved by the present invention:

[0082] 1. The method for pre-treating paper containing saccharin sodium of the present invention does not require extraction operation and can be implemented on-site on a large scale, facilitating subsequent detection by near-infrared diffuse reflectance spectroscopy.

[0083] 2. The method for determining the content of saccharin sodium in paper of the present invention has high accuracy and high reliability.

[0084] 3. The pretreatment device of the present invention can be used to implement the method of pretreatment of paper containing saccharin sodium of the present invention.

[0085] 4. The method for determining the content of saccharin sodium in paper of the present invention can be implemented by using the determination system of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0086] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein

[0087] Figure 1 A schematic diagram of an embodiment of a device for pre-treating paper containing saccharin sodium according to the present invention;

[0088] Figure 2 A schematic diagram of an embodiment of a system for measuring the content of saccharin sodium in paper according to the present invention;

[0089] Figure 3 It is a flow chart of the method for determining the saccharin sodium content of cigarette tipping paper in an embodiment of the present invention;

[0090] Figure 4 is a near-infrared diffuse reflectance spectrum of a standard sample in an embodiment of the present invention;

[0091] Figure 5 for Figure 4 Preprocessing of spectrograms: Spectrograms;

[0092] Figure 6 is a quantitative model in an embodiment of the present invention;

[0093] Among them: 1 is a sprayer, 1-1 is a nozzle, 2 is a UV reactor, 2-1 is a UV lamp, 3 is a dryer, 3-1 is a heating plate, 4 is a constant temperature and humidity controller, 5 is a cooler, 5-1 is a cold air inlet, 5-2 is a waste gas outlet, 6 is a conveying device, 6-1 is a conveyor belt, 6-2 is a transmission wheel, 7 is a near-infrared diffuse reflectance spectrometer, 7-1 is an opaque white board, and 7-2 is an infrared probe. DETAILED DESCRIPTION

[0094] The embodiments of the present invention will be described clearly and completely below in conjunction with the examples. Obviously, the described examples are only some examples of the present invention, rather than all examples. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the examples in the present invention, all other examples obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention.

[0095] Figure 1A schematic diagram of an embodiment of a device for pre-treating paper containing saccharin sodium according to the present invention;

[0096] The device comprises a sprayer 1, an ultraviolet reactor 2, a dryer 3 and a constant temperature and humidity controller 4; wherein,

[0097] The sprayer 1 is provided with an inlet and an outlet, and a nozzle 1-1 is provided inside the sprayer 1 for spraying a mixture of ethyl acetate and ethanol onto the paper containing saccharin sodium;

[0098] The ultraviolet reactor 2 is provided with an inlet and an outlet, the inlet of the ultraviolet reactor 2 is connected to the outlet of the sprayer 1, and an ultraviolet lamp 2-1 is provided in the ultraviolet reactor 2 for irradiating the sprayed paper with ultraviolet light;

[0099] The dryer 3 is provided with an inlet and an outlet, the inlet of the dryer 3 is connected to the outlet of the ultraviolet reactor 2, and a heating plate 3-1 is provided in the dryer 3 for drying the paper irradiated by ultraviolet light;

[0100] The thermostat 4 is provided with an inlet and an outlet. The inlet of the thermostat 4 is connected to the outlet of the dryer 3 and is used for standing the dried paper under constant temperature and humidity conditions.

[0101] In this embodiment, the nozzles 1 - 1 in the sprinkler 1 are arranged in a matrix.

[0102] In this embodiment, the ultraviolet lamp 2 - 1 in the ultraviolet reactor 2 is tubular.

[0103] In this embodiment, the heating plates 3 - 1 are arranged on two opposite inner walls of the dryer 3 .

[0104] In this embodiment, the device also includes a conveying device 6, which includes a conveyor belt 6-1 and a transmission wheel 6-2. The transmission wheel 6-2 drives the conveyor belt 6-1 to pass through the inlets and outlets of the four devices of the sprayer 1, the ultraviolet reactor 2, the dryer 3 and the constant temperature and humidity controller 4 for transmission. The conveying device 6 is used to transport paper.

[0105] In this embodiment, the device further comprises a cooler 5, and the inlet of the thermostat 4 is connected to the outlet of the dryer 3 through the cooler 5.

[0106] In this embodiment, the conveyor belt 6 - 1 of the conveying device 6 passes through the cooler 5 for conveying.

[0107] In this embodiment, the cooler 5 is provided with a cold air inlet 5-1 and an exhaust gas outlet 5-2.

[0108] In this embodiment, the volume ratio of ethyl acetate to ethanol in the mixed solution is 1:(40-90).

[0109] In this embodiment, the wavelength of the ultraviolet light is 300-330 nm.

[0110] In this embodiment, the drying temperature is 30°C to 60°C.

[0111] In this embodiment, the constant temperature and humidity are 15° C. to 30° C., and the relative humidity is 25% to 55%.

[0112] In this embodiment, the cooling temperature is 15°C to 28°C.

[0113] Figure 2 A schematic diagram of an embodiment of a system for measuring the content of saccharin sodium in paper according to the present invention;

[0114] The system comprises Figure 1 The device shown and the near-infrared diffuse reflectance spectrometer 7; wherein the near-infrared diffuse reflectance spectrometer 7 is provided with an inlet and an outlet, and the inlet of the near-infrared diffuse reflectance spectrometer 7 is connected to the outlet of the constant temperature and humidity controller 4.

[0115] In this embodiment, the conveyor belt 6 - 1 of the conveying device 6 passes through the inlet and outlet of the near-infrared diffuse reflectance spectrometer 7 for transmission.

[0116] In this embodiment, a light-proof white plate 7 - 1 and an infrared probe 7 - 2 are provided in the near-infrared diffuse reflectance spectrometer 7 .

[0117] In this embodiment, the near-infrared diffuse reflectance spectrometer 7 is a Fourier transform near-infrared diffuse reflectance spectrometer using a diffuse reflectance spectrum sampling module.

[0118] Example Method for Determining the Content of Saccharin Sodium in Cigarette Tipping Paper

[0119] The method for determining the content of saccharin sodium in cigarette tipping paper in this embodiment is as follows: Figure 2 The system implementation shown.

[0120] 1. Materials and instruments:

[0121] The cigarette tipping paper of the same brand was purchased from Gaoyou Satellite Cigarette Material Co., Ltd. The cigarette tipping paper was divided into two groups, one group as a standard group (n=100) and the other group as a test group (n=3).

[0122] Fourier transform near-infrared spectrometer: purchased from ThermoFisher Scientific, model Antaris II, including diffuse reflectance spectrum sampling module and TQ Analyst intelligent analysis software.

[0123] The method for determining the content of saccharin sodium in cigarette tipping paper is as follows:

[0124] (I) Accurately pipette 2.5 ml of saccharin sodium standard (1.0 mg / ml) into a 25 mL volumetric flask and dilute to scale with ultrapure water to obtain a 0.1 mg / ml saccharin sodium standard stock solution. Accurately measure 50 μl, 100 μl, 200 μl, 400 μl, and 800 μl of the standard stock solution, respectively, and dilute to 10 ml with ultrapure water to prepare standard working solutions with contents of 0.005 mg / ml, 0.010 mg / ml, 0.020 mg / ml, 0.040 mg / ml, and 0.080 mg / ml, respectively.

[0125] (II) Weigh 0.2 g of cigarette tipping paper accurately to 0.001 g, place in a 50 ml stoppered conical flask, add 20 ml of water accurately, let stand for 60 min, then sonicate for 60 min. After sonication, let stand for more than 1 h, shake well, filter through a microporous membrane, and the filtrate is ready for analysis;

[0126] (III) 10 μl of the filtrate and the standard working solution were injected into a high performance liquid chromatograph for detection, and a reagent blank control experiment was performed for each batch of detection;

[0127] The operating conditions of HPLC are as follows:

[0128] Chromatographic column: C18 column, 250mm×4.6mm, 5μm; mobile phase: methanol+ammonium acetate solution (5+95); flow rate: 1ml / min; detection wavelength: 230nm; injection volume: 10μl.

[0129] (IV) Using the retention time of the standard working solution peak as a qualitative basis, a standard curve is established according to the peak area (after deducting the blank control peak area) and concentration of the standard working solution, and the peak area of ​​the filtrate (after deducting the blank control peak area) is substituted into the standard curve to calculate the saccharin sodium content in the filtrate, and then the saccharin sodium content in the cigarette tipping paper is calculated.

[0130] (II) Method for determining the content of saccharin sodium in cigarette tipping paper, the process is as follows Figure 3 As shown, including:

[0131] (1) Pretreatment of standard cigarette tipping paper:

[0132] The front and back sides of each cigarette tipping paper in the standard group were evenly sprayed with a mixture of ethyl acetate and ethanol (the volume ratio of ethyl acetate to ethanol was 1:65) through a spray box, with a spray volume of 3-4 ml / m 2Immediately after spraying, irradiate the surface of the paper sprayed with the mixed liquid with ultraviolet light of 300-330nm wavelength (generated by an ultraviolet lamp with an operating voltage of 3V-5V) for 5 seconds, then dry the paper at 40°C for 6-10 seconds on an electric hot plate, cool to 25°C, and then place the paper in a constant temperature and humidity chamber at 25°C and 40% relative humidity for 1 hour to obtain a standard sample.

[0133] (2) Pre-treatment of the tipping paper of the tested group of cigarettes:

[0134] The tipping papers of the cigarettes in the test group are processed in the same manner as in step (1) to obtain the test samples.

[0135] (3) Detection:

[0136] The diffuse reflectance spectrum sampling module of the Fourier transform near-infrared spectrometer is used to detect the standard sample and the sample to be tested; the acquisition wave number range is 10000~4000cm -1 , the number of scans is 68 times, the resolution is 8cm -1 , with an opaque white board as the background, each sample was tested three times and the average spectrum was taken. Among them, the average spectrum of multiple standard samples is as follows Figure 4 As shown, “R” indicates absorbance.

[0137] TQ Analyst intelligent analysis software was used to pre-process the near-infrared spectra as follows: a. Standard canonical transformation (SNV) was used to eliminate the differences caused by sample inhomogeneity; b. First-order derivative processing was used to eliminate the influence of baseline drift and obtain higher resolution and clearer spectral profile changes than the original spectrum; c. Norris filtering with a segment length of 5 and an interval of 5 was used to smooth the spectrum, eliminate high-frequency noise, and retain useful low-frequency information. Among them, Figure 4 The spectra shown in the figure are preprocessed as follows Figure 5 shown.

[0138] (4) Establishment of quantitative model:

[0139] Select 5299.43~4064.92cm in the preprocessed standard group spectrum -1 The spectra in the wavenumber range were subjected to partial least squares regression with the saccharin sodium content of the standard group of cigarette tipping paper to establish a quantitative model, such as Figure 6 shown.

[0140] The obtained quantitative model was calibrated and cross-validated, and the parameters were shown in Table 1.

[0141] Table 1 Calibration parameters and cross-validation parameters of quantitative models

[0142]

[0143] As shown in Table 1, the correction mean square error and cross-validation mean square error of the quantitative model are both small, indicating that the quantitative model has high accuracy and the measured value is closer to the true value. The measurement range of the quantitative model is 0.01-0.95 mg / g.

[0144] (5) Calculation results:

[0145] Substituting the spectral results of the samples to be tested into the quantitative model, the calculated values ​​of the saccharin sodium content of the cigarette tipping paper in the test group were obtained. The results are shown in Table 2.

[0146] Table 2 Actual and calculated values ​​of saccharin sodium content in cigarette tipping paper of the tested group

[0147]

[0148] It can be seen from Table 2 that the relative error between the saccharin sodium content in the cigarette tipping paper determined by the method of the present invention and the true value of the saccharin sodium content does not exceed 4%, indicating that the determination accuracy of the method of the present invention is high.

[0149] Comparative Example

[0150] The pre-treatment operation of steps (1)-(2) in item (ii) of the embodiment is omitted, and the spectrum of the standard group of cigarette tipping paper is directly detected according to step (3) in item (ii) of the embodiment and the quantitative model is established according to step (4). The obtained quantitative model is calibrated and cross-validated, and the parameters are shown in Table 3.

[0151] Table 3 Calibration parameters and cross-validation parameters of proportional quantitative model

[0152]

[0153] As shown in Table 3, the corrected mean square error and cross-validation mean square error of the comparative quantitative model are both greater than 0.4, indicating that the quantitative model has low accuracy and the measured values ​​deviate greatly from the true values, making it impossible to accurately determine the saccharin sodium content of cigarette tipping paper.

[0154] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A method for pre-treating paper containing saccharin sodium, comprising the following steps: (1) spraying a mixture of ethyl acetate and ethanol onto at least one surface of a paper containing saccharin sodium, and then immediately irradiating the surface with ultraviolet light having a wavelength of 200 to 400 nm; wherein: The volume ratio of ethyl acetate to ethanol in the mixed solution is 1:(40-90); (2) drying the paper at 30°C to 60°C; optionally, cooling the dried paper to 15°C to 28°C; (3) The dried or cooled paper is allowed to stand at 15°C to 30°C and a relative humidity of 25% to 55% to obtain pre-treated paper.

2. The method according to claim 1, wherein: In step (1), the ultraviolet light irradiation time is 1 to 10 seconds.

3. The method according to claim 1, characterized in that One or more of the following A to I: A. In step (1), the spraying amount of the mixed liquid is 1~30ml / m 2 Paper; B. In step (2), the drying time is 1 to 40 seconds; C. In step (3), the standing time is 0.5 to 10 hours; D. In step (1), spraying the mixture onto both surfaces of the paper containing sodium saccharin; E. In step (1), the mixed solution is sprayed using a spray box; F. In step (1), ultraviolet light with a wavelength of 200 to 400 nm is generated by an ultraviolet lamp; G. In step (2), drying is performed using a heating plate; H. In step (3), place the sample in a constant temperature and humidity chamber; I. The paper is cigarette paper.

4. The method according to claim 3, wherein: In item F, in step (1), the operating voltage of the UV lamp is 3~5V.

5. The method according to claim 3, wherein: In item I, the paper is selected from cigarette tipping paper, cigarette paper, filter rod forming paper and cigarette label paper.

6. The method according to claim 3, wherein: In item I, the paper is cigarette tipping paper.

7. A method for determining the content of saccharin sodium in paper, comprising the following steps: 1) Pre-treating paper containing saccharin sodium according to the method of any one of claims 1 to 6 to obtain pre-treated paper; 2) using near-infrared diffuse reflectance spectroscopy to detect the pretreated paper to obtain a detection spectrum; optionally, preprocessing the detection spectrum to obtain a preprocessed spectrum; 3) Substitute the detected spectrum or pre-processed spectrum into the quantitative model to calculate and obtain the saccharin sodium content in the paper.

8. The method according to claim 7, wherein: In step 3), the quantitative model is obtained by a method comprising the following steps: (i) pre-treating a paper standard product with a known saccharin sodium content according to the method of any one of claims 1 to 6 to obtain a pre-treated paper standard product; (ii) using near infrared diffuse reflectance spectroscopy to detect the pre-treated paper standard to obtain a standard spectrum; optionally, pre-processing the standard spectrum to obtain a pre-processed standard spectrum; (iii) The standard spectrum or the pre-processed standard spectrum was regressed with the saccharin sodium content of the paper standard by partial least squares method to obtain a quantitative model.

9. The method according to claim 7 or 8, characterized in that One or more of the following a to h: a. In step 2) and / or step (ii), the collection wave number range of near infrared diffuse reflectance spectroscopy is 15000~2000cm -1 ; b. In step 2) and / or step (ii), the number of scans used in the near-infrared diffuse reflectance spectroscopy is 40 to 80 times; c. In step 2) and / or step (ii), the resolution of near-infrared diffuse reflectance spectroscopy is 5~12cm -1 ; d. In step 2) and / or step (ii), near-infrared diffuse reflectance spectroscopy is used to detect an opaque white board as the background; e. In step 2) and / or step (ii), the near-infrared diffuse reflectance spectroscopy is Fourier transform near-infrared diffuse reflectance spectroscopy; f. In step 2) and / or step (ii), TQ Analyst intelligent analysis software is used for pre-processing; g. In step (iii), select 5299.43-4064.92 cm from the standard spectrum or the pre-processed standard spectrum. -1 The spectra in the wavenumber range were regressed with the sodium saccharin content of the paper standard using partial least squares method; h. In step 3), detect the spectrum or pre-process the spectrum between 5299.43 and 4064.92 cm -1 The spectra in the wavenumber range are substituted into the quantitative model for calculation.

10. A device for pre-treating paper containing sodium saccharin, comprising a sprayer, an ultraviolet reactor, a dryer and a constant temperature and humidity controller; wherein: The sprayer is provided with an inlet and an outlet, and a spray head is provided inside the sprayer for spraying a mixture of ethyl acetate and ethanol onto the paper containing saccharin sodium; The ultraviolet reactor is provided with an inlet and an outlet, the inlet of the ultraviolet reactor is connected to the outlet of the sprayer, and an ultraviolet lamp is provided in the ultraviolet reactor for irradiating the sprayed paper with ultraviolet light; The dryer is provided with an inlet and an outlet, the inlet of the dryer is connected to the outlet of the ultraviolet reactor, and a heating plate is provided in the dryer for drying the paper irradiated by ultraviolet light; The thermostat and humidistat is provided with an inlet and an outlet, and the inlet of the thermostat and humidistat is connected with the outlet of the dryer, and is used for standing the dried paper under constant temperature and humidity conditions.

11. The device according to claim 10, wherein: The nozzles in the sprinkler are arranged in a matrix.

12. The device according to claim 10, wherein: The UV lamp in the UV reactor is tubular.

13. The device according to claim 10, wherein: The heating plates are arranged on two opposite inner walls of the dryer.

14. The device according to claim 10 further comprises a conveying device, which comprises a conveyor belt and a transmission wheel, and the conveyor belt is driven by the transmission wheel to pass through the inlets and outlets of the four devices of the sprayer, the ultraviolet reactor, the dryer and the constant temperature and humidity controller for transmission, and the conveying device is used to transport paper.

15. The device according to any one of claims 10 to 14, further comprising a cooler, through which the inlet of the thermo-hygrostat is connected to the outlet of the dryer.

16. The device according to claim 15, wherein: The conveyor belt of the conveying device passes through the cooler for conveying.

17. The device according to claim 15, wherein: The cooler is provided with a cold air inlet and an exhaust gas outlet.

18. A system for determining the content of saccharin sodium in paper, comprising the device according to any one of claims 10 to 17 and a near-infrared diffuse reflectance spectrometer; wherein: The near-infrared diffuse reflectance spectrometer is provided with an inlet and an outlet, and the inlet of the near-infrared diffuse reflectance spectrometer is connected with the outlet of the constant temperature and humidity controller.

19. The system of claim 18, wherein: The conveyor belt of the conveying device passes through the entrance and exit of the near-infrared diffuse reflectance spectrometer for transmission.

20. The system of claim 18, wherein: The near-infrared diffuse reflectance spectrometer is provided with an opaque white board and an infrared probe.

21. The system of claim 18, wherein: The near-infrared diffuse reflectance spectrometer is a Fourier transform near-infrared diffuse reflectance spectrometer.

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