Quantitative detection method for residual photoinitiator TPO in optical fiber coating

Abstract

The invention relates to a quantitative detection method for residual photoinitiator TPO in an optical fiber coating. The quantitative detection method comprises the following steps: weighing a quantitative coating sample, adding an organic solvent for ultrasonic extraction, centrifuging to remove insoluble substances, and collecting supernate to obtain a solution to be detected; weighing a TPO standard substance, adding an organic solvent to dissolve and fix the volume, and preparing standard solutions with different concentrations; carrying out full-wavelength scanning on the to-be-detected solution and the standard solution by using an ultraviolet and visible spectrophotometer, and collecting absorption spectrum data; drawing an initial standard curve and fitting a linear regression equation by taking the TPO concentration of the standard solution as a vertical coordinate and the absorbance of the standard solution as a horizontal coordinate; respectively carrying out second derivative processing on the acquired absorption spectrum data of the solution to be detected and the standard solution to eliminate interference, selecting a peak value at a target wavelength as a TPO quantitative basis, drawing a second derivative standard curve and fitting a linear regression equation; and calculating the concentration of the residual TPO in the optical fiber coating according to the second derivative standard curve and the absorbance of the solution to be detected.

Description

Technical Field

[0001] The present invention relates to the technical field of optical fiber coating detection, and particularly relates to a method for quantitatively detecting residual photoinitiator TPO in an optical fiber coating. Background Art

[0002] The optical fiber coating is a key functional layer in the optical fiber manufacturing process, usually made of ultraviolet (UV) curable materials such as acrylate or epoxy resin systems. Its main functions are to provide mechanical protection, reduce microbending loss, and improve the stability of the optical fiber in complex environments. This coating achieves rapid curing through UV light irradiation to initiate a polymerization reaction, and the photoinitiator is a key component. 2,4,6-Trimethylbenzoyl-diphenylphosphine oxide (TPO) is a commonly used photoinitiator, which has advantages such as high reactivity and low yellowing property, and is widely used in the optical fiber coating system. However, the concentration of TPO in the coating directly affects the curing effect and the performance of the finished product: insufficient concentration will lead to incomplete curing, affecting the coating adhesion and hardness; excessive concentration may cause the coating to become brittle or have residual toxicity, thereby affecting the product reliability. Therefore, accurately determining the residual amount of TPO in the coating is an important link in the optical fiber quality control.

[0003] The existing TPO detection methods mainly include gas chromatography-mass spectrometry (GC-MS) and high performance liquid chromatography (HPLC). However, due to the large molecular weight and extremely high boiling point of TPO, it is difficult to achieve effective vaporization in GC-MS and thus cannot enter the chromatographic column for analysis, resulting in limited detection sensitivity and accuracy. Although HPLC has good separation ability, it has expensive equipment, complex pretreatment processes, and high requirements for solvent purity, making it difficult to meet the needs of rapid detection in industrial fields. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for quantitatively detecting residual photoinitiator TPO in an optical fiber coating, which can obtain a test solution through ultrasonic extraction and detect the concentration of residual TPO in the optical fiber coating in combination with ultraviolet spectrophotometry. It can be applied to various types of optical fiber coatings, effectively detect the TPO residue in the optical fiber coating, provide a reliable method for the quality control of optical fiber coatings and the environmental safety assessment, with simple operation, fast detection speed, and no need for complex pretreatment steps and expensive instruments.

[0005] To achieve the above purpose, the present invention provides a method for quantitatively detecting residual photoinitiator TPO in an optical fiber coating, including the following steps:

[0006] Weigh a quantitative coating sample, add an organic solvent for ultrasonic extraction, centrifuge to separate and remove insoluble substances, and collect the supernatant to obtain a test solution;

[0007] Weigh the TPO reference standard, dissolve it in an organic solvent and make up the volume to prepare standard solutions with different concentrations.

[0008] Use a UV-Vis spectrophotometer to perform a full-wavelength scan on the test solution and the standard solutions, and collect absorption spectral data for absorbance measurement.

[0009] Take the TPO concentration of the standard solutions as the ordinate and the absorbance of the standard solutions as the abscissa to plot the initial standard curve and fit the linear regression equation.

[0010] Perform second derivative processing on the collected absorption spectral data of the test solution and the standard solutions respectively to eliminate interference, select the peak value at the target wavelength as the basis for TPO quantification, plot the second derivative standard curve and fit the linear regression equation.

[0011] Calculate the concentration of residual TPO in the optical fiber coating according to the second derivative standard curve and the absorbance of the test solution.

[0012] Optionally, when performing second derivative processing on the collected absorption spectral data of the test solution and the standard solutions respectively, the selected target wavelength is 379 nm - 383 nm.

[0013] Optionally, the organic solvent is any one or more of tetrahydrofuran, acetone, chloroform, ethanol, methanol, toluene, dichloromethane, ethyl acetate, n-butanol, N,N-dimethylformamide.

[0014] Optionally, the blending volume ratio of the two organic solvents is 1 - 5:1.

[0015] Optionally, in the step of weighing a quantitative coating sample, adding an organic solvent for ultrasonic extraction, centrifuging to remove insoluble substances, and collecting the supernatant to obtain the test solution, the ultrasonic extraction time is 20 - 40 minutes, the centrifugation speed is 5000 rpm - 8000 rpm, and the centrifugation time is 5 - 15 minutes.

[0016] Optionally, the concentration range of the prepared standard solutions is 0.1 μg / mL - 1000 μg / mL, and the detection wavelength when using a UV-Vis spectrophotometer to perform a full-wavelength scan on the test solution and the standard solutions is 300 nm - 500 nm.

[0017] Optionally, the quantitative detection method for residual photoinitiator TPO in the optical fiber coating further includes the following steps:

[0018] Add an antioxidant to the prepared test solution and standard solutions to inhibit the photodegradation of TPO.

[0019] Optionally, the quantitative detection method for residual photoinitiator TPO in the optical fiber coating further includes the following steps:

[0020] An internal standard substance is added to the prepared test solution, and the concentration of residual TPO in the optical fiber coating is corrected by the internal standard method.

[0021] Optionally, before weighing a quantitative coating sample, adding an organic solvent for ultrasonic extraction, centrifuging to separate and remove insoluble substances, and collecting the supernatant to obtain the test solution, the following steps are further included:

[0022] Use pure organic solvent for baseline correction.

[0023] The beneficial effects of the present invention are as follows: By obtaining the test solution through ultrasonic extraction and cooperating with ultraviolet spectrophotometry to detect the concentration of residual TPO in the optical fiber coating, it can be applicable to various types of optical fiber coatings, effectively detect the TPO residue in the optical fiber coating, provide a reliable method for the quality control of optical fiber coatings and environmental safety assessment, with simple operation, fast detection speed, no need for complex pretreatment steps and expensive instruments;

[0024] Using an organic solvent to co-extract the residual TPO in the optical fiber coating can improve the extraction effect of the optical fiber coating compared with the limitation of a single solvent;

[0025] Using second derivative to process data to eliminate the interference of other components in the optical fiber coating. By amplifying the inflection point characteristics of the absorption curve, the wide peak interference signal (such as resin monomer) is converted into low-amplitude oscillation, and the sharp derivative peak of TPO at 381 nm is highlighted, which is more applicable to the scenario of unknown interfering substances than the traditional background subtraction method;

[0026] Introducing an internal standard substance in the detection process, by standardizing the signal ratio, reducing the influence of spectral baseline drift caused by matrix interference, especially applicable to fluctuations generated in a production environment with complex changes such as temperature and operation time;

[0027] By adding an antioxidant to the test solution and the standard solution to scavenge free radicals and block the chain degradation reaction of TPO, the experimental error caused by the photodegradation of TPO during the detection can be inhibited, ensuring the accuracy of the test results.

[0028] The above description is only an overview of the technical solution of the present invention. In order to be able to understand the technical means of the present invention more clearly and implement it according to the content of the specification, the following takes the preferred embodiment of the present invention and combines with the attached drawings to elaborate in detail as follows. Description of the Drawings

[0029] Figure 1 It is a schematic flow chart of a method for quantitatively detecting residual photoinitiator TPO in an optical fiber coating shown in an embodiment of the present invention;

[0030] Figure 2An initial standard curve graph is plotted with the concentration of the standard solution as the ordinate and the absorbance of the standard solution as the abscissa as shown in an embodiment of the present invention; Detailed implementation manners

[0031] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0032] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0033] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations. In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0034] Please refer to Figure 1 A method for quantitatively detecting residual photoinitiator TPO in an optical fiber coating as shown in a preferred embodiment of the present application includes the following steps:

[0035] Step S10: Weigh a quantitative coating sample, add an organic solvent for ultrasonic extraction, centrifuge to separate and remove insoluble substances, and collect the supernatant to obtain a solution to be measured;

[0036] Step S20: Weigh a TPO standard product, dissolve it in an organic solvent and make up the volume to prepare standard solutions with different concentrations;

[0037] Step S30: Use a UV-visible spectrophotometer to perform a full-wavelength scan on the solution to be measured and the standard solutions, and collect absorption spectrum data for absorbance measurement;

[0038] Step S40: Taking the TPO concentration of the standard solution as the ordinate and the absorbance of the standard solution as the abscissa, plot the initial standard curve and fit the linear regression equation;

[0039] Step S50: Perform second derivative processing on the absorption spectral data of the collected test solution and the standard solution respectively to eliminate interference. Select the peak value at the target wavelength as the basis for TPO quantification, plot the second derivative standard curve and fit the linear regression equation;

[0040] Step S60: Calculate the concentration of residual TPO in the optical fiber coating according to the second derivative standard curve and the absorbance of the test solution.

[0041] It should be noted that the types of optical fiber coatings applicable to this method include acrylate, epoxy resin, and polyurethane UV curable coatings, and the coating thickness range is 10μm - 300μm. At the same time, if the concentration of TPO in the test solution exceeds the linear detection range of the standard curve, in order to ensure the accuracy of quantitative analysis and the applicability of the linear regression formula, the test solution should be appropriately diluted with the same type of organic solvent so that its absorbance value (or second derivative value) falls within the concentration range covered by the standard curve; when finally calculating the actual concentration of TPO in the test solution, the diluted concentration obtained by calculating through the standard curve needs to be multiplied by the corresponding dilution factor to obtain the true concentration of TPO in the test solution.

[0042] This method obtains the supernatant as the test sample through ultrasonic extraction combined with centrifugation operation, avoiding the interference of impurities in the sample on the test results; then scanning with a UV-visible spectrophotometer and combining with the standard solution to draw the standard curve, especially using the second derivative technology to process the absorption spectral data, effectively improving the specific recognition ability of TPO, enhancing the sensitivity and anti-interference ability of the detection, and providing a reliable basis for the quality control and process optimization of optical fiber coatings.

[0043] In an embodiment, the detection wavelength when using a UV-visible spectrophotometer to perform full wavelength scanning on the test solution and the standard solution is 300nm - 500nm. Perform second derivative processing on the absorption spectral data of the collected test solution and the standard solution respectively. The preferred target wavelength is 379nm - 383nm, for example, it can be 379nm, 380nm, 381nm, 382nm, 383nm. This wavelength range is the region where the TPO absorption peak is the most significant. Selecting this wavelength as the quantitative criterion after second derivative processing can effectively avoid background interference and co-absorption of other components, and significantly improve the specificity of the test results and the data repeatability.

[0044] In one embodiment, the organic solvent is any one or more of tetrahydrofuran (THF), acetone, chloroform (CHCl3), ethanol, methanol, toluene, dichloromethane, ethyl acetate, n-butanol, and N,N-dimethylformamide (DMF). The blending volume ratio of the two organic solvents is 1-5:1, for example, it can be 1:1, 2:1, 3:1, 4:1, 5:1. Specifically, the single solvent is preferably THF because it has better solubility for TPO; the blending system is preferably THF:CHCl3 = 3:1. THF has excellent solubility for acrylate resins but is difficult to break the cross-linked structure, while CHCl3 enhances the mobility of polymer segments through swelling. After the two are mixed, they can synergistically improve the TPO release efficiency (>90%) and break through the extraction limitations of a single solvent.

[0045] In one embodiment, in step S10, the ultrasonic extraction time is 20-40 minutes, for example, it can be 20 minutes, 30 minutes, 40 minutes, the centrifugation speed is 5000 rpm - 8000 rpm, for example, it can be 5000 rpm, 6000 rpm, 7000 rpm, 8000 rpm, and the centrifugation time is 5-15 minutes, for example, it can be 5 minutes, 10 minutes, 15 minutes. The optimized pretreatment parameters not only improve the extraction efficiency of TPO but also avoid quantitative errors caused by insufficient or excessive treatment, ensuring the consistency of the samples and the repeatability of the method.

[0046] In one embodiment, the concentration range for preparing the standard solution is 0.1 μg / mL - 1000 μg / mL to ensure the accuracy and applicability of the standard curve. For example, it can be 0.1 μg / mL, 0.5 μg / mL, 1 μg / mL, 5 μg / mL, 10 μg / mL, 20 μg / mL, 50 μg / mL, 100 μg / mL, 500 μg / mL, 1000 μg / mL, and preferably 0.5 μg / mL, 1 μg / mL, 5 μg / mL, 10 μg / mL, 100 μg / mL.

[0047] In one embodiment, the method for quantitatively detecting the residual photoinitiator TPO in the optical fiber coating further includes the following steps:

[0048] Add an antioxidant to the prepared test solution and standard solution to inhibit the photodegradation of TPO.

[0049] Specifically, in this embodiment, add an antioxidant BHT (butylated hydroxytoluene) with a mass fraction of 0.01% - 0.1% to the test solution to inhibit the photodegradation of TPO. By adding an antioxidant to the solution to scavenge free radicals, the degradation reaction of TPO during the detection process can be effectively inhibited, avoiding analysis errors caused by light, solvent reactions, or environmental oxidation.

[0050] In one embodiment, the method for quantitatively detecting the residual photoinitiator TPO in the optical fiber coating further comprises the following steps:

[0051] An internal standard is added to the prepared solution to be measured, and the concentration of the residual TPO in the optical fiber coating is corrected by the internal standard method.

[0052] Specifically, in this embodiment, the internal standard method is introduced for correction in step S60. The internal standard is 4-nitrophenol (detection wavelength 310 nm), and the internal standard concentration is fixed at 5 μg / mL. 4-Nitrophenol is introduced into the detection process as an internal standard. By standardizing the signal ratio (TPO / internal standard), the influence of spectral baseline drift caused by matrix interference can be reduced, especially applicable to the fluctuations generated in a production environment with complex changes in temperature and operation time.

[0053] In one embodiment, before step S10, the following steps are further included:

[0054] Perform baseline correction using pure organic solvent.

[0055] Before sample pretreatment, adding a baseline correction step to establish a zero background using pure organic solvent can effectively eliminate the interference of the solvent itself on the detection result. This step enhances the accuracy of data analysis and the clarity of interpretation, especially playing a key supporting role in the detection of low-content TPO.

[0056] To illustrate the performance effects of the embodiments of the present invention, the following specific examples are used for detailed description:

[0057] Example 1: Direct determination of the TPO content in an optical fiber sample by the linear regression initial standard curve method

[0058] Take 4 optical fiber samples from different sources, strip their outer coatings respectively, accurately weigh 0.02 g of the coating sample and place it in a centrifuge tube, add 10 mL of tetrahydrofuran (THF), and perform ultrasonic extraction for 30 minutes. Then centrifuge at 8000 rpm for 10 minutes, and take the supernatant as the solution to be measured, denoted as SAMPLE 1 to SAMPLE 4 respectively;

[0059] Accurately weigh 10 mg of the TPO standard, dissolve it with THF and make up the volume to 10 mL to obtain a 1 mg / mL mother liquor. Then sequentially dilute and prepare standard solutions with concentrations of 0.5 μg / mL, 1 μg / mL, 5 μg / mL, 10 μg / mL, and 100 μg / mL;

[0060] Use a UV-visible spectrophotometer to perform baseline correction with THF as the blank at a wavelength of 381 nm, and sequentially measure the absorbances of the standard solutions and the solutions to be measured;

[0061] Plot the initial standard curve with the concentration of the standard solution as the ordinate and the absorbance of the standard solution as the abscissa (see Figure 2 ), and obtain the linear equation y = ax + b by regression fitting.

[0062] Substitute the absorbance of the solution to be measured into the linear equation to calculate its TPO concentration. If the concentration of the solution to be measured exceeds the linear range of the initial standard curve, it is necessary to first dilute the solution to be measured with THF to the linear range and then multiply by the dilution factor to obtain the actual concentration of TPO. The quantitative results of TPO in each optical fiber coating are shown in Table 1:

[0063]

[0064] Result analysis: According to Table 1, there are significant differences in the TPO content of the 4 optical fiber samples. Among them, the TPO content of SAMPLE 4 is the highest, reaching 92.21 μg / mL, indicating that there may be high-dose photoinitiator residues, and its production process and curing efficiency need to be further analyzed; while the content of SAMPLE 1 is the lowest, only 6.77 μg / mL, indicating that the cleanliness of this batch of optical fibers is relatively high or less TPO additive is used.

[0065] Example 2: Comparative experiment on extraction efficiency of blended organic solvents and single organic solvents

[0066] Take a sample of acrylate resin coating from a certain manufacturer (the nominal TPO content is 1.0 wt%). Weigh 6 portions of 0.05 g of the sample into centrifuge tubes respectively, add 10 mL of each solvent shown in Table 2 below, ultrasonically extract for 30 minutes, centrifuge at 8000 rpm for 10 minutes, and take the supernatant as the solution to be measured, denoted as SAMPLE 5 to SAMPLE 10;

[0067] Determine the TPO content of SAMPLE 5 to SAMPLE 10 respectively according to the detection method of Example 1.

[0068]

[0069] The calculation formula for extraction efficiency is as follows:

[0070] Extraction efficiency = measured TPO concentration / (sample mass × TPO nominal content) × 100%

[0071] The measured TPO concentrations and extraction efficiency results of different solutions are shown in Table 3 below:

[0072]

[0073]

[0074] Result analysis: The results show that when the THF-CHCl3 mixed solvent is prepared at a volume ratio of 3:1, the extraction efficiency is the highest, reaching 92.3%, which is significantly higher than that of THF alone (78.2%). This is because chloroform in the mixed solvent helps to break the cross-linked structure, enhancing the release and dissolution of TPO, thus achieving synergistic enhancement. When using single solvents such as chloroform or acetone, the extraction efficiency decreases significantly, being 65.4% and 70.1% respectively, indicating that there are certain limitations in the release of TPO in the coating by single solvents.

[0075] Example 3: Experiment on the inhibition of TPO photodegradation by antioxidant BHT

[0076] Prepare 2 portions of 10 μg / mL TPO standard solutions, denoted as SAMPLE 11 (added with 0.05 wt% BHT) and SAMPLE 12 (without BHT, as the control group);

[0077] Place the two samples in an ultraviolet lamp box, irradiate continuously at 25 °C, and take 1 mL of samples at 0, 15, 30, 60, and 120 minutes respectively, and store them in the dark;

[0078] Complete the absorbance detection and calculate the TPO concentration within 30 minutes according to the detection method in Example 1.

[0079] The experimental results are shown in Table 4 below:

[0080]

[0081] Result analysis: The experimental data shows that after 120 minutes of irradiation, the remaining concentration of TPO in SAMPLE 11 is 9.12 μg / mL, and the degradation rate is only 8.8%. While the remaining concentration of the control group SAMPLE 12 is 4.75 μg / mL, and the degradation rate is as high as 52.5%. The results prove that BHT as an antioxidant can effectively capture free radicals and inhibit the photodegradation process of TPO, significantly improving its stability, and is suitable for the preservation of photosensitive materials.

[0082] Example 4: Internal standard calibration experiment

[0083] Prepare 2 portions of optical fiber coating dissolution solutions with a TPO concentration of 5 μg / mL, denoted as SAMPLE 13 (without internal standard) and SAMPLE 14 (added with 5 μg / mL of 4-nitrophenol as the internal standard);

[0084] Artificially introduce operation errors in both groups of samples, including 10% solvent evaporation (volume reduced to 9 mL) and shortening the centrifugation time to 5 minutes;

[0085] The peak area ratio of TPO at 381 nm and the internal standard at 310 nm was determined according to the detection method of Example 1, and the TPO content was corrected with the internal standard.

[0086] The calculation formula of the internal standard method is as follows:

[0087] TPO concentration = sample peak area ratio / initial standard curve slope × internal standard concentration

[0088] The experimental results are shown in Table 5 below:

[0089]

[0090] Result analysis: When not corrected with the internal standard, the measured TPO concentration of SAMPLE 13 was 4.2 μg / mL, with a large deviation; while after adding the internal standard to SAMPLE 14, the corrected result was 4.9 μg / mL, which was closer to the true value. This shows that the internal standard method can significantly reduce the interference of human error on the quantitative result and enhance the accuracy and stability of the method.

[0091] Example 5: Verification experiment on the anti-interference ability of the second derivative spectroscopy method for coexisting interfering substances

[0092] A 5.0 μg / mL TPO standard solution was prepared, and 25 μg / mL photoinitiator 1173 and 50 μg / mL silicone leveling agent were added as interference items to simulate a multi-component complex system, denoted as SAMPLE 15;

[0093] The actual concentration of TPO was determined according to the detection method (direct spectroscopy method) of Example 1;

[0094] The standard curve was drawn using the second derivative spectroscopy method, including the following steps:

[0095] Accurately weigh the TPO standard product, dissolve it with a solvent and make up the volume to prepare a series of standard solutions with different concentrations;

[0096] Use an ultraviolet-visible spectrophotometer to perform a full-wavelength scan on the solution to be measured and the standard solutions, and collect the absorption spectrum data;

[0097] The measured spectral data were respectively subjected to second derivative processing, and the peak value at 381 ± 2 nm was selected as the basis for TPO quantification, and the second derivative standard curve y = 0.0215x + 0.0032 (R2 = 0.9996) was drawn;

[0098] The absorption spectrum of SAMPLE 15 measured by the direct spectroscopy method was processed by the second derivative to measure the absorbance at 381 ± 2 nm, and it was substituted into the second derivative standard curve equation to calculate the TPO content of the solution to be measured.

[0099] The experimental results are shown in Table 6 below:

[0100]

[0101] Result analysis: The concentration of TPO measured by the direct spectroscopy method is 4.25 μg / mL, with an error of -15%, while the concentration of TPO measured by the second derivative method is 4.90 μg / mL, and the error is only -2%. It shows that in a system with strong background interference, the second derivative treatment can significantly improve the problems of peak overlap and baseline drift, and enhance the resolution and accuracy of quantitative analysis.

[0102] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0103] The above-described embodiments only represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the invention patent should be subject to the appended claims.

Claims

1. A quantitative detection method for residual photoinitiator TPO in an optical fiber coating, characterized in that, It includes the following steps: Weigh a quantitative coating sample, add an organic solvent for ultrasonic extraction, centrifuge to separate and remove insoluble substances, and collect the supernatant to obtain the solution to be measured; Weigh TPO standard products, dissolve them in an organic solvent and make up the volume to prepare standard solutions with different concentrations; Use a UV-visible spectrophotometer to perform full-wavelength scanning on the solution to be measured and the standard solutions, and collect absorption spectrum data for absorbance measurement; Take the TPO concentration of the standard solutions as the ordinate and the absorbance of the standard solutions as the abscissa to plot the initial standard curve and fit the linear regression equation; Perform second derivative processing on the collected absorption spectrum data of the solution to be measured and the standard solutions respectively to eliminate interference, select the peak value at the target wavelength as the basis for TPO quantification, plot the second derivative standard curve and fit the linear regression equation; Calculate the concentration of residual TPO in the optical fiber coating according to the second derivative standard curve and the absorbance of the solution to be measured.

2. The quantitative detection method for residual photoinitiator TPO in the optical fiber coating according to claim 1, wherein The second derivative processing of the collected absorption spectrum data of the solution to be measured and the standard solutions respectively is carried out, and the selected target wavelength is 379nm - 383nm.

3. The quantitative detection method of the residual photoinitiator TPO in the optical fiber coating according to claim 1, wherein The organic solvent is any one or several of tetrahydrofuran, acetone, chloroform, ethanol, methanol, toluene, dichloromethane, ethyl acetate, n-butanol, N,N-dimethylformamide.

4. The quantitative detection method of the residual photoinitiator TPO in the optical fiber coating according to claim 3, characterized in that, The blending volume ratio of the two organic solvents is 1 - 5:

1.

5. The quantitative detection method of residual photoinitiator TPO in the optical fiber coating according to claim 1, characterized in that, In the step of weighing a quantitative coating sample, adding an organic solvent for ultrasonic extraction, centrifuging to remove insoluble substances, and collecting the supernatant to obtain the solution to be measured, the ultrasonic extraction time is 20 - 40 minutes, the centrifugal speed is 5000rpm - 8000rpm, and the centrifugal time is 5 - 15 minutes.

6. The quantitative detection method of residual photoinitiator TPO in the optical fiber coating according to claim 1, wherein The concentration range of the prepared standard solutions is 0.1μg / mL - 1000μg / mL, and the detection wavelength during the full-wavelength scanning of the solution to be measured and the standard solutions using the UV-visible spectrophotometer is 300nm - 500nm.

7. The quantitative detection method of residual photoinitiator TPO in the optical fiber coating according to claim 1, characterized in that, It also includes the following steps: Add an antioxidant to the prepared solution to be measured and the standard solutions to inhibit the photodegradation of TPO.

8. The quantitative detection method for residual photoinitiator TPO in the optical fiber coating according to claim 1, characterized in that, It also includes the following steps: Add an internal standard to the prepared solution to be measured, and correct the concentration of residual TPO in the optical fiber coating by the internal standard method.

9. The quantitative detection method for residual photoinitiator TPO in the optical fiber coating according to claim 1, characterized in that, Before the step of weighing a quantitative coating sample, adding an organic solvent for ultrasonic extraction, centrifuging to separate and remove insoluble substances, and collecting the supernatant to obtain the solution to be measured, it also includes the following steps: Perform baseline correction using a pure organic solvent.

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