Device and method for detecting chlorosilane

Abstract

The invention relates to the technical field of chemical gas chromatography analysis and detection, in particular to a device and method for chlorosilane detection, and the method comprises the following steps: inserting a needle head of an injector into a chlorosilane sample bottle, pulling back a push rod at a pulling-back speed of v, and extracting a sample of V1; the needle head of the injector faces upwards, bubbles float upwards to the top and are pushed and injected until the bubbles are discharged, and the needle cylinder is filled with the sample; according to the method, the needle head is inserted into a sample inlet of a heated gas chromatograph for detection, and the problem of inaccurate sample injection volume caused by bubbles generated by rapid volatilization of chlorosilane is effectively avoided through the steps of slow liquid extraction and bubble discharge, so that the accuracy of gas chromatography detection data and the repeatability of an experiment are remarkably improved; after the injection is finished, the specific high temperature of the sample inlet is combined, so that the chlorosilane sample is ensured to be instantly and completely gasified, the needle head is prevented from being remained or the sample is prevented from being volatilized in advance in the needle, the detection integrity is ensured, and the cross contamination of the sample inlet and a chromatographic column is avoided.

Description

Technical Field

[0001] This invention relates to the field of chemical gas chromatography analysis and detection technology, and in particular to an apparatus and method for the detection of chlorosilanes. Background Technology

[0002] Chlorosilanes are core raw materials in the semiconductor and photovoltaic industries (e.g., trichlorosilane is a key intermediate in the preparation of polycrystalline silicon and silane gas), but they are extremely chemically reactive, exhibiting strong corrosiveness (easily reacting with metals and glass), easy hydrolysis, and high volatility (some varieties have low boiling points). In industrial production, rapid and accurate gas chromatography (GC) analysis of the composition and impurity content of chlorosilanes is a crucial step in quality control. However, the extremely high chemical reactivity (easily hydrolyzed, easily reacting with metals / glass) and volatility of chlorosilanes pose significant challenges to traditional GC injection operations, leading to the following systemic defects in existing detection methods:

[0003] When a traditional syringe rapidly draws chlorosilane, a momentary negative pressure is generated inside the syringe, causing the chlorosilane component with a low boiling point to "flash evaporate" and generate a large number of microbubbles. These bubbles are difficult to completely remove in subsequent degassing operations, resulting in the actual sample volume entering the chromatographic column being smaller than the set value, causing the peak area to be low and the quantification to be inaccurate, with detection deviations often reaching 5% to 10%.

[0004] Existing methods lack standardized operating parameters (such as extraction speed, degassing criteria, and injection speed). Operators often rely on experience for control, resulting in significant differences between different personnel and different operations. The relative standard deviation (RSD) of the test results is often greater than 3%, which cannot meet the data precision requirements of modern industry.

[0005] To address the technical problems existing in the prior art, a device and method for the detection of chlorosilanes are proposed. Summary of the Invention

[0006] In this section, as well as in the abstract and title of this application, some simplifications or omissions may be made to avoid obscuring the purpose of this section, the abstract, and the title of this application, and such simplifications or omissions shall not be used to limit the scope of the invention.

[0007] To address the shortcomings of existing technologies, one objective of this invention is to provide an apparatus for the detection of chlorosilanes.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: a device for detecting chlorosilanes, comprising a syringe for containing chlorosilanes, and a push rod movable inside the syringe, wherein the internal volume of the syringe is V. c Represented as: , When performing chlorosilane sample extraction and testing, the push rod pull-back speed Q is 0.05 ~ 0.15 mL / s, and the push rod stroke change rate v s The following relationship must be satisfied: , Among them, A b S is the cross-sectional area of ​​the syringe. max π is the maximum stroke of the push rod, π is the mathematical constant pi, and D is the inner diameter of the syringe.

[0009] In a preferred embodiment of the device for detecting chlorosilanes according to the present invention, the syringe is made of polypropylene or polyethylene resistant to chlorosilane corrosion, and its internal volume V c The nominal value is nmL, and the cylinder body is marked with a volume mark based on the minimum scale of stroke S of 0.1nmL, where n≤3.

[0010] As a preferred embodiment of the device for detecting chlorosilanes according to the present invention, it further includes a needle connected to a syringe, wherein the length L of the needle satisfies 25 mm ≤ L ≤ 50 mm.

[0011] As a preferred embodiment of the device for detecting chlorosilanes according to the present invention, the inner diameter d of the needle satisfies 0.1 mm ≤ d ≤ 0.2 mm.

[0012] The device for detecting chlorosilanes according to the present invention has the following advantages: it directly solves the core problem of flash evaporation and bubble generation of chlorosilanes caused by negative pressure generated by rapid liquid extraction, thus eliminating the generation of bubbles at the source and laying a solid foundation for subsequent accurate sample injection. Combined with the cylindrical structure of the syringe and the volume formula, it forms a complete device solution with calculable parameters and controllable operation.

[0013] To address the shortcomings of the prior art, another objective of this invention is to provide a method for detecting chlorosilanes.

[0014] To achieve the above objectives, the present invention adopts the following technical solution: a method for detecting chlorosilanes, comprising an apparatus for detecting chlorosilanes, comprising the following steps: inserting the needle of a syringe into a chlorosilane sample vial, pulling back the plunger at a pullback speed of v to extract a sample of V1; pointing the needle of the syringe upwards to allow air bubbles to rise to the top, pushing the syringe to expel the air bubbles and fill the syringe with the sample; inserting the needle into the injection port of a preheated gas chromatograph for detection.

[0015] In a preferred embodiment of the method for detecting chlorosilanes according to the present invention, the volume V1 of the extracted chlorosilane sample is 0.45~0.55 mL, and the injection time T satisfies the following: , Where F is the push rod thrust and μ is the dynamic viscosity of the chlorosilane sample.

[0016] In a preferred embodiment of the method for detecting chlorosilanes described in this invention, the time for inserting the needle into the heated gas chromatograph injection port and simultaneously completing the injection is T≤1s.

[0017] In a preferred embodiment of the method for detecting chlorosilanes according to the present invention, the completion of the defoaming is indicated by visually observing the precipitation of a complete sample droplet at the tip of the needle.

[0018] As a preferred embodiment of the method for detecting chlorosilanes according to the present invention, the chlorosilane sample includes, but is not limited to, dichlorosilane, trichlorosilane, silicon tetrachloride, or mixtures thereof.

[0019] As a preferred embodiment of the method for detecting chlorosilanes according to the present invention, the injection port temperature of the heated gas chromatograph is between 120°C and 180°C during detection.

[0020] The beneficial effects of the method for detecting chlorosilanes according to the present invention are as follows: by using slow liquid extraction and degassing steps, the problem of inaccurate injection volume caused by bubbles generated by the rapid volatilization of chlorosilanes is effectively avoided, thereby significantly improving the accuracy of gas chromatography detection data and the repeatability of experiments. After injection, combined with the specific high temperature of the injection port, it is ensured that the chlorosilane sample is completely vaporized instantly, and needle residue or premature volatilization of the sample in the needle is prevented, ensuring the integrity of the detection and avoiding cross-contamination of the injection port and chromatographic column. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a partial schematic diagram of the device of the present invention.

[0023] Figure 2 This is a schematic diagram of the overall device of the present invention.

[0024] Figure 3 This is a flowchart of the detection method of the present invention.

[0025] In the diagram, 101 is the syringe; 102 is the plunger; 103 is the needle; and 104 is the sealing cap. Detailed Implementation

[0026] To make the objectives, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0027] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0028] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0029] Reference Figure 1 This embodiment provides an apparatus for detecting chlorosilanes, including a cylindrical syringe 101 for containing chlorosilanes, and a push rod 102 movable inside the syringe 101, wherein the internal volume V of the syringe 101 is... c Represented as: , When performing chlorosilane sample extraction and testing, the pull-back speed Q of push rod 102 is 0.05 ~ 0.15 mL / s, and the stroke change rate of push rod 102 is... The following relationship must be satisfied: , Among them, A b S is the cross-sectional area of ​​syringe 101. max Let π be the maximum stroke of push rod 102, π be pi, and D be the inner diameter of syringe 101. The derivation process is as follows: Let the volume of the sample extracted within time t be V1, then the volumetric flow rate Q is defined by Formula 1: , For a cross-sectional area of ​​A b The displacement S of the cylindrical syringe 101 and the push rod 102 satisfies Formula 2 with respect to the extraction volume: , v s Defined as the rate of change of displacement of push rod 102 with time, i.e., Formula 3: , Simultaneous derivation of the core formula: Substituting Formula 2 into Formula 1, we obtain Formula 4: , When the pullback speed Q is limited to 0.05~0.15 mL / s, substituting into Formula 4, the moving speed of push rod 102 can be solved. Constraint range: , , Experiment: Validation of chromatographic precision (actual GC experiment)

[0030] In this stage, samples at different extraction speeds are actually injected into the GC, and the precision of the final analysis results is used as the gold standard for evaluation.

[0031] Group experiment: Select a representative velocity point in the first stage for actual sample injection.

[0032] Experimental design: Each velocity point is treated as an experimental group, and each group is injected at least 5 times (n≥5).

[0033] Data collection: Record the chromatographic peak area of ​​the target component (such as trichlorosilane) after each injection.

[0034] Calculate the relative standard deviation (RSD%) of the peak area for 5 repeated injections within each rate group.

[0035] RSD is a key indicator for measuring operational precision (reproducibility). The smaller the RSD, the more stable and reliable the results are under the operating conditions.

[0036] Table 1

[0037] Overall evaluation: A flow rate of 0.02 mL / s is feasible but not efficient; a flow rate of 0.05 mL / s is the lower limit of the recommended range; a flow rate of 0.10 mL / s is the optimal recommended value; a flow rate of 0.15 mL / s is the upper limit of the recommended range; a flow rate of 0.25 mL / s is not recommended; and a flow rate of 0.50 mL / s is not feasible.

[0038] As shown in Table 1, a faster pumping speed (e.g., >0.2 mL / s) will result in a significant negative pressure in syringe 101. This negative pressure will then cause the chlorosilane to flash and generate bubbles. Although subsequent bubble removal operations were performed, there are still residues. This ultimately leads to inaccurate and fluctuating actual injection volume, resulting in an increase in the RSD of the chromatographic peak area.

[0039] Controlling the flow rate within the range of 0.05~0.15 mL / s ensures stable pressure changes, effectively preventing flash evaporation and bubble generation of chlorosilanes. Due to the absence of bubble interference, thorough venting and precise actual injection volume result in optimal reproducibility of chromatographic analysis results, with the relative standard deviation (RSD) at its minimum.

[0040] This directly solves the core problem of chlorosilane flash evaporation and bubble generation caused by negative pressure generated by rapid liquid extraction, eliminating bubble generation at the source and laying a solid foundation for subsequent accurate sample injection. Combined with the cylindrical structure and volume formula of syringe 101, a complete device solution with calculable parameters and controllable operation is formed.

[0041] Reference Figure 2 The syringe 101 is made of polypropylene or polyethylene resistant to chlorosilane corrosion, and its internal volume V c The nominal value is nmL, and the cylinder is marked with a volume mark based on the stroke S with a minimum scale of 0.1nmL, where n≤3.

[0042] Preferably, n is 1, and the internal volume V c The syringe has a capacity of 1.0 mL and a volume marking of 0.1 mL based on the stroke S. With a total capacity of 1.0 mL and a high-precision 0.1 mL scale, it is particularly suitable for the accurate measurement of small samples of about 0.5 mL, ensuring the accuracy of the injection volume. Made of polypropylene or polyethylene, it can effectively resist the chemical corrosion of chlorosilanes, preventing the syringe 101 from being dissolved, deformed, or generating impurities during the short injection process, ensuring the purity of the sample and the authenticity and reliability of the test results. The matching sealing cap 104 can seal the needle 103 before and after injection, effectively preventing the leakage of highly volatile and highly reactive chlorosilanes, protecting the safety of operators and reducing environmental pollution.

[0043] The syringe 101 is made of polypropylene or polyethylene, which is resistant to chlorosilane corrosion. Chlorosilanes (such as SiHCl3 and SiCl4) are characterized by high reactivity, especially their Si-Cl bonds, which readily react with groups containing active hydrogen (such as -OH and -NH2). Many common syringe materials react with chlorosilanes, leading to serious consequences. For example, glass syringes, whose main component is silicon dioxide, have a large number of silanol groups (-Si-OH) on their surface. Chlorosilanes react violently with these hydroxyl groups, causing sample decomposition, corrosion and roughening of the inner wall of the syringe 101, and blockage of the needle 103 by solid precipitates. Furthermore, the pressure generated by the reaction may cause the plunger 102 to pop out unexpectedly, which is extremely dangerous. Similarly, rubber / elastomer sealing rings (common in some syringes) are also problematic. Many rubber materials (such as butyl rubber) contain unsaturated bonds or additives that react with or swell with chlorosilanes, leading to seal failure and sample contamination. Polypropylene and polyethylene, on the other hand, are inert, non-polar hydrocarbon polymers with stable molecular structures and do not contain functional groups that readily react with chlorosilanes. Therefore, they can provide a relatively "inert" environment for chlorosilanes, ensuring that the chemical composition of the sample remains unchanged to the maximum extent possible before it enters the gas chromatograph.

[0044] Furthermore, it also includes a needle 103 connected to the syringe 101. The length L of the needle 103 satisfies 25 mm ≤ L ≤ 50 mm. Its main purpose is that the injection port of the gas chromatograph usually has a thick heat insulation pad and a relatively deep liner. The needle 103 must be long enough to penetrate the pad and deliver the sample directly to the designated hot zone of the liner. A needle 103 shorter than 25 mm may not be able to effectively reach the optimal vaporization position. Conversely, the longer the needle 103 is, the larger its heat exchange area with the high-temperature injection port, and the higher the risk of heat conduction back into the needle 103. Although high-speed flow is the main countermeasure, limiting the length is another important safeguard to ensure that the sample is not heated prematurely inside the syringe.

[0045] Furthermore, the inner diameter d of the needle 103 satisfies 0.1 mm ≤ d ≤ 0.2 mm. Controlling the inner diameter to 0.1 mm to 0.2 mm essentially means that at the same injection speed, a smaller inner diameter will significantly increase the flow rate of the liquid sample. Just like blocking part of the water outlet with your finger, it will spray farther and faster. The extremely high flow rate makes the liquid sample vaporize inside the needle 103 because it does not have enough time to absorb enough heat.

[0046] Reference Figure 3 This embodiment provides a method for detecting chlorosilanes, including the following steps: Insert the syringe needle 103 into the chlorosilane sample vial, and pull back the plunger 102 at a speed of 0.05~0.15mL per second to extract a certain amount of sample, avoiding the generation of bubbles due to the volatilization of chlorosilane caused by rapid liquid extraction.

[0047] With the needle 103 of the syringe facing upwards, allow the mixed air bubbles to rise to the top of the syringe 101. Slowly push the plunger 102 until the air bubbles are completely expelled, allowing the sample liquid to fill the needle plug cavity at the front end of the syringe 101.

[0048] Quickly insert the needle 103 into the gas chromatograph injection port that has been heated to 120~180℃ and complete the injection. After the injection is completed, immediately pull out the syringe and put on the sealing cap 104.

[0049] The used syringe, along with its sealing cap 104, is sealed in a dedicated waste container and disposed of as chemical waste.

[0050] By employing slow liquid extraction and bubble removal steps, the problem of inaccurate injection volume caused by bubbles generated from the rapid volatilization of chlorosilane is effectively avoided. This significantly improves the accuracy of gas chromatography detection data and the repeatability of experiments. After injection, combined with a specific high temperature at the injection port, the chlorosilane sample is ensured to be completely vaporized instantly, preventing 103 residue in the needle or premature evaporation of the sample inside the needle. This ensures the integrity of the detection and avoids cross-contamination of the injection port and chromatographic column. The used syringe is sealed and disposed of as chemical waste, eliminating chemical risks and environmental pollution caused by reuse or improper disposal, and improving the safety of experimental operations.

[0051] Furthermore, the volume V1 of the extracted chlorosilane sample is 0.45~0.55 mL, and the injection time T is simultaneously satisfied: , Where F is the thrust of push rod 102, and μ is the dynamic viscosity of the chlorosilane sample. The derivation process is as follows: For an incompressible Newtonian fluid in steady laminar flow in a horizontal circular pipe, the volumetric flow rate Q flow The relationship between the pressure difference Y across the pipe and the pipe's geometric dimensions is given by Formula 5: , Where r is the radius of the pipe (here, the inner radius of the needle 103, r=d / 2).

[0052] The time T required to complete the injection of volume V1 is equal to the volume divided by the flow rate, as shown in Formula 6: , The force F that pushes the push rod 102 acts on the cross-sectional area A of the syringe 101. b The pressure generated above is P. push =F / A b Neglecting other minor resistances, this pressure is approximately equal to the pressure difference Y of the driving fluid passing through needle 103, i.e., Equation 7: , Substituting formulas 5 and 7 into formula 6, we obtain formula 8: , This is the basic theoretical formula for the sample injection time T.

[0053] Substituting the preferred sampling volume range V1 = 0.45~0.55mL into Formula 8, we can obtain the lower limit of time by taking V1 = 0.45mL and the upper limit of time by taking V1 = 0.55mL. To simplify the expression of the formula, we combine the constants 0.45 and 0.55 with the constant coefficients in Formula 8 to obtain the above formula.

[0054] The reason for extracting 0.45~0.55mL of sample is as follows: the excess sample is used to rinse and wet the dead volume of the syringe (the inside of the syringe 101 and the connection of the needle 103, etc.), to ensure that the sample finally pushed into the injection port is representative and not diluted by residual solvent or air, and to provide sufficient liquid volume to safely expel air bubbles in the syringe without causing insufficient sample volume after expelling air bubbles. At the same time, it gives the operator a buffer space so that even if some liquid is lost during the expelling or injection process, there is still enough sample for accurate injection, as detailed in Table 2.

[0055] Experiment: Samples: a standard solution of trichlorosilane (SiHCl3) of known concentration, and a mixed sample of chlorosilanes containing trace amounts of dichlorosilane and silicon tetrachloride.

[0056] Apparatus: The 1.0mL dedicated polypropylene syringe of the present invention (needle 103 inner diameter d=0.15mm, length L=30mm).

[0057] Instrument: Gas chromatograph (configuration and conditions are the same as in the previous example).

[0058] The operating parameters are fixed: pullback volumetric flow rate Q = 0.1 mL / s, sample injection time T < 1 s, and injection port temperature = 140℃; Table 2

[0059] Test / Calculation Method Description: Peak area RSD%: The relative standard deviation of the peak area of ​​the target analyte was calculated for each group of 10 injections.

[0060] Defoaming failure rate: Record the number of times a complete droplet failed to form after defoaming / total number of times (10 times).

[0061] Fault tolerance test results: After simulating "excessive defoaming" and losing 0.02 mL, can the remaining sample be effectively injected with a peak area deviation of <5%?

[0062] Flushing effect evaluation: Qualitatively assess the adequacy of dead volume flushing.

[0063] Sample / time consumption: relative evaluation.

[0064] Qualitative assessment of volatility risk: a comprehensive assessment based on the total volume of the sample in the syringe and its residence time.

[0065] Comprehensive evaluation: The evaluation is based on the combined peak area RSD%, defoaming failure rate, fault tolerance test results, rinsing effect assessment, sample / time consumption, and qualitative assessment of volatilization risk.

[0066] As shown in Table 2, controlling the sampling volume V1 within the range of 0.45 mL to 0.55 mL is the optimal and necessary choice for achieving high-precision and high-reproducibility gas chromatographic detection of chlorosilanes. The lower limit of 0.45 mL ensures the critical point of basic performance; below this value, precision and operational stability decrease significantly. The upper limit of 0.55 mL provides the maximum operational tolerance while maintaining excellent performance; exceeding this value leads to unnecessary sample waste and increased risk.

[0067] Furthermore, the needle 103 is inserted into the preheated gas chromatograph injection port for detection, and the injection time T is satisfied: T≤1s, and the injection port temperature is as high as 120~180℃. The purpose is to ensure that the liquid sample is completely and rapidly vaporized at the moment of entry. If the syringe needle tip stays in the high-temperature injection port for too long (e.g., more than 1 second), the sample inside the needle 103 will be heated and evaporated before the push rod 102. For mixtures with a wide boiling point range (chlorosilanes may contain impurities with different boiling points), if the evaporation process is slow, the low-boiling-point components will vaporize more easily, while the high-boiling-point components may remain. This will lead to the sample composition entering the chromatographic column being inconsistent with the actual liquid composition. The peak of the low-boiling-point component will be artificially enlarged, and the peak of the high-boiling-point component will be smaller. If the process is completed within 1 second, it ensures that after the needle 103 is inserted, the sample is squeezed into the high-temperature vaporization chamber by the mechanical action of the push rod 102, and then vaporizes synchronously and instantaneously, thereby maximizing the authenticity of the sample composition. See Table 2 for details.

[0068] Experimental materials and equipment

[0069] Sample: A standard sample of chlorosilane mixtures with known proportions (e.g., a mixture of dichlorosilane, trichlorosilane, and silicon tetrachloride at known concentrations), which is key to verifying “discriminatory volatilization”.

[0070] Syringe: A standard 1.0mL polypropylene syringe.

[0071] Key tool: Stopwatch or high-speed timer, used to precisely control the total dwell time from the insertion of the needle tip into the injection pad to the complete removal of the needle after injection.

[0072] Analytical instrument: Gas chromatograph (conditions as before).

[0073] Experimental procedures and data collection: Multiple different injection time points were designed. For all experiments, the liquid was first aspirated (0.5 mL, speed 0.1 mL / s) and the bubbles were removed using the standard method. The operator inserted the needle 103 into the 120℃ injection port, started the timer, and injected the plunger 102 at a constant speed to ensure that the injection was completed exactly at the set time point (e.g., 1.0 second) and immediately pulled out, so that the injection speed matched the time (e.g., to complete the injection within 1 second, a fast injection was required, and to complete the injection within 5 seconds, an extremely slow injection was required). Each time point was used as an experimental group, and the same standard sample was injected at least 4 times. After completion, the data were recorded.

[0074] Table 3

[0075] The above experiments clearly show that injection time is a key parameter affecting peak shape and quantification. Using 1.0 second as the standard operating time can ensure the best balance between accurate results (no significant deviation) and operational feasibility. Although 0.5 seconds is theoretically optimal, it is demanding for operators and difficult to reproduce. When the injection time is ≥2.0 seconds, the risk of peak broadening and quantification distortion increases significantly, and the reliability of the method decreases sharply, which should be strictly avoided.

[0076] When the injection time exceeds 1-2 seconds, the peak area ratio of low-boiling-point components to high-boiling-point components begins to increase systematically. High-boiling-point components remain relatively in the needle tip 103, while low-boiling-point components enter the system in relatively more. At the same time, the peak half-width increases significantly with the increase of injection time, resulting in a decrease in chromatographic resolution. Only under rapid injection conditions of about 1 second can the measured composition be consistent with the true composition of the standard sample, and the peak shape remain sharp.

[0077] Furthermore, the sign that the degassing is complete is visually observed that a complete sample droplet precipitates at the tip of the needle 103. When a droplet can be formed at the tip of the needle 103, it proves that the liquid has traveled from the rear of the syringe 101, through the needle plug, through the entire internal channel of the needle 103, and finally reached the tip. This means that the air bubbles that were originally present in the needle 103 and the tip of the syringe 101 have been completely expelled. Because gas is compressible, if there are still air bubbles in the channel, the liquid cannot be continuously pushed to the tip of the needle 103 and form a droplet.

[0078] Furthermore, the chlorosilane samples include, but are not limited to, dichlorosilane, trichlorosilane, silicon tetrachloride, or mixtures thereof.

[0079] Furthermore, the injection port temperature of the heated gas chromatograph is between 120℃ and 180℃. The inventors conducted the following experiments to select this temperature.

[0080] Experimental materials and equipment

[0081] Samples: Trichlorosilane (SiHCl3) standard of known purity, and mixed chlorosilane samples containing impurities such as dichlorosilane and silicon tetrachloride.

[0082] Apparatus: The special syringe of the present invention (1.0mL polypropylene syringe 101, inner diameter d=0.15mm, length L=30mm).

[0083] Instrument: Gas chromatograph equipped with a packed column and a thermal conductivity detector (TCD).

[0084] Key parameters: Chromatographic column: SE-30 packed column, with a constant column temperature of 50℃.

[0085] Detector (TCD) temperature: constant at 140°C.

[0086] Carrier gas: high-purity nitrogen, flow rate 30 mL / min.

[0087] The only variable is the injection port temperature; multiple gradients are set for testing.

[0088] Experimental steps

[0089] Sample preparation and injection: Strictly follow the method of this invention (pull-back speed Q=0.1mL / s, sample volume V1=0.5mL, after degassing, complete rapid injection within T≤1s).

[0090] Temperature gradient test: Select multiple temperature points (such as 90, 110, 120, 140, 160, 180, 200℃) within the range of 90℃ to 200℃ for testing.

[0091] Data acquisition: At each temperature point, the same sample was injected three times, and the following key data were recorded: Retention time and peak area of ​​the trichlorosilane main peak.

[0092] Half-peak width of the main peak (used to evaluate the sharpness of the peak shape).

[0093] Separation (evaluation of the separation effect from neighboring impurity peaks).

[0094] Observe for any abnormal peaks (such as tailing, forward extension, bifurcation, or unknown small peaks, which may be decomposition products).

[0095] Table 4 (Effect of different injection port temperatures on the GC analytical performance of chlorosilanes (trichlorosilanes)) Inlet temperature (°C) Main peak retention time (min) Main peak area RSD (%, n=3) Half-peak width of the main peak (s) Separation from recent impurity peaks Peak shape description and anomalies 90 2.45 1.8% 3.8 1.2 The peak shape is slightly broad with a slight tail; high-boiling-point impurity peaks were not completely detected. 110 2.43 1.2% 2.5 1.5 The peak shape is basically symmetrical, with no obvious abnormal peaks. 120 2.42 0.5% 1.8 1.8 The peaks are sharp and symmetrical, with no abnormal peaks. 140 2.41 0.5% 1.7 1.8 The peaks are sharp and symmetrical, with no abnormal peaks. 160 2.40 0.6% 1.7 1.7 Sharp peaks and stable baselines 180 2.39 0.7% 1.8 1.6 The peak shape remains sharp, but the baseline noise has increased slightly. 200 2.37 1.5% 2.2 1.4 A small, unknown peak appears (approximately 0.1% of the area), and the main peak shows a slight forward extension.

[0096] As shown in Table 4: Lower limit 120°C: Below this temperature (e.g., 110°C), the sample vaporization efficiency decreases, resulting in a broadened main peak shape and tailing. Furthermore, high-boiling-point impurities may not be detected due to incomplete vaporization, affecting the accuracy and reproducibility of the analysis. Considering that trichlorosilane has a boiling point of only 31.8°C, 120°C provides sufficient energy for its rapid and complete vaporization.

[0097] Upper limit 180℃: Above this temperature (e.g., 200℃), although the main peak remains relatively sharp, signs of increased baseline noise and even the appearance of small, unknown peaks begin to appear. This may be due to thermal decomposition of trace samples caused by high temperature or system interference. At the same time, the main peak shows a slight forward extension, indicating that the temperature is approaching the critical point affecting the peak shape.

[0098] A temperature of 120~180℃ ensures that the liquid chlorosilane sample is completely converted into gas the moment it enters the injection port (in conjunction with rapid injection with T≤1s). This is a prerequisite for obtaining an accurate and reproducible chromatographic response. This range is far below the temperature threshold (usually >250℃) at which chlorosilane undergoes significant thermal decomposition, thus avoiding the generation of decomposition products due to excessively high temperatures, which could interfere with the main peak and contaminate the system.

[0099] Furthermore, this temperature matches well with the recommended column temperature (50℃) and detector temperature (140℃) gradients, ensuring good initial focusing and subsequent separation of the sample in the chromatographic column.

[0100] Furthermore, gas chromatography also includes a thermal conductivity detector and a packed column.

[0101] The thermal conductivity detector temperature is set to 140℃ to prevent sample components from condensing upon reaching the detector. The reason for choosing 140℃ is that there is a basic principle for setting the temperature of the TCD detector: it must be at least 10-20℃ higher than the highest temperature of the column. In this method, the column temperature is 50℃ (initial), and 140℃ is much higher than this, which can effectively prevent any high-boiling-point components from condensing in the detector, avoiding detector contamination and memory effect. This temperature is usually set to be higher than the highest point of the column temperature. 140℃ is a conservative and safe setting for the current isothermal analysis at 50℃, and it must never be lower than the column temperature.

[0102] The packed column temperature is set to 50°C, which determines the distribution equilibrium of each component between the stationary and mobile phases. 50°C is an isothermal analysis temperature. For samples like chlorosilanes, which have low boiling points and relatively simple components, a column temperature of 50°C provides sufficient separation without excessively long analysis times. If the temperature is set too high (e.g., 80°C), all components will pass through the column too quickly, potentially leading to separation issues. If the temperature is set too low (e.g., 30°C), the analysis time will become very long, and peak shapes may diffuse.

[0103] If the separation effect is not ideal, the most common method is to use programmed temperature: for example, initially hold at 50°C for 2 minutes, and then increase to 80°C at a rate of 10°C / min. This can take into account both the separation of low-boiling-point components and the detection of high-boiling-point impurities. Therefore, 50°C is the optimized condition for this specific chlorosilane sample and this specific chromatographic column. If the sample or chromatographic column is changed, this temperature may need to be re-optimized.

[0104] Compared with existing technologies, our invention is as follows: Table 5

[0105] Table 6

[0106] Table 5 shows the test results using our disposable (polypropylene or polyethylene) medical or veterinary syringes (1.0 mL), and Table 6 shows the test results using a glass microsyringe (10 μL). It can be seen that the test deviation is smaller when using this method.

[0107] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. An apparatus for detecting chlorosilanes, characterized in that: include, A syringe (101) for containing chlorosilane, and a push rod (102) movable inside the syringe (101), the internal volume of which is V. c Represented as: ， When performing chlorosilane sample extraction and detection, the pull-back speed Q of the push rod (102) is 0.05 ~ 0.15 mL / s, and the stroke change rate v of the push rod (102) is... s The following relationship must be satisfied: ， Among them, A b S is the cross-sectional area of ​​the syringe (101). max π is the maximum stroke of the push rod (102), π is the circumference ratio, and D is the inner diameter of the syringe (101).

2. The apparatus for detecting chlorosilanes as described in claim 1, characterized in that: The syringe (101) is made of polypropylene or polyethylene resistant to chlorosilane corrosion, and its internal volume V c The nominal value is nmL, and the cylinder body is marked with a volume of 0.1nmL based on the minimum scale of the stroke S; Where n≤3.

3. The apparatus for detecting chlorosilanes as described in claim 1 or 2, characterized in that: It also includes a needle (103) connected to the syringe (101), the length L of which satisfies 25 mm ≤ L ≤ 50 mm.

4. The apparatus for detecting chlorosilanes as described in claim 3, characterized in that: The inner diameter d of the needle (103) satisfies 0.1 mm ≤ d ≤ 0.2 mm.

5. A method for detecting chlorosilanes, comprising the apparatus for detecting chlorosilanes as described in claims 1-4, characterized in that: Includes the following steps: Insert the syringe needle (103) into the chlorosilane sample vial, pull back the push rod (102) at a pullback speed of v, and extract the sample of V1; Point the syringe needle (103) upwards to allow the air bubble to rise to the top, then inject until the air bubble is expelled, filling the syringe (101) with the sample. Insert the needle (103) into the injection port of the heated gas chromatograph for detection.

6. The method for detecting chlorosilanes as described in claim 5, characterized in that: The volume V1 of the extracted chlorosilane sample is 0.45~0.55mL, and the injection time T satisfies the following: ， Where F is the thrust of the push rod (102) and μ is the dynamic viscosity of the chlorosilane sample.

7. The method for detecting chlorosilanes as described in claim 6, characterized in that: The time T ≤ 1s is used to insert the needle (103) into the heated gas chromatograph injection port for detection and to complete the injection.

8. The method for detecting chlorosilanes according to any one of claims 5 to 7, characterized in that: The completion of defoaming is indicated by visual observation of a complete sample droplet precipitated at the tip of the needle (103).

9. The method for detecting chlorosilanes as described in claim 8, characterized in that: The chlorosilane samples include, but are not limited to, dichlorosilane, trichlorosilane, silicon tetrachloride, or mixtures thereof.

10. The method for detecting chlorosilanes as described in any one of claims 5, 6, 7, and 9, characterized in that: During detection, the injection port temperature of the heated gas chromatograph is between 120℃ and 180℃.

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