Organic sample analysis method based on micro gas chromatography and chromatographic analyzer

Abstract

The invention discloses an organic sample analysis method based on micro gas chromatography and a chromatographic analyzer, particularly relates to the technical field of micro gas chromatography, and is used for solving the problems of unstable separation performance and low complex sample detection precision caused by insufficient uniformity of a stationary phase coating of an existing micro chromatographic column. The method comprises the following steps: constructing a stationary phase distribution initial profile by continuously pre-charging carrier gas, alternately applying segmented temperature gradient, micro-negative pressure and directional pulse flow to remodel a uniform distribution layer, generating a correction factor set of a temperature-resistance coupling relationship by combining a correction mixture and a tracer gas pulse, dynamically adjusting a carrier gas flow velocity and a temperature program to generate a matched operation curve, and finally, carrying out dynamic calibration. High-precision separation detection and quantitative analysis are achieved, stable separation performance is maintained in a miniaturized structure by cooperatively controlling stationary phase distribution optimization and real-time parameter feedback correction, and the detection precision and reproducibility of a wide-boiling-range organic mixture are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of micro gas chromatography analysis, and more specifically, to an organic sample analysis method and a chromatograph based on micro gas chromatography. Background Art

[0002] By miniaturizing the traditional gas chromatography system, micro gas chromatography can significantly improve the portability and analysis speed of the equipment, making it suitable for the on-site rapid detection of organic samples. During the miniaturization process, the reduction in the size of the chromatographic column poses challenges to the internal stationary phase coating process. Existing technologies usually use microfabrication means to achieve the loading of the stationary phase in the microcolumn. However, limited by the physical scale and processing accuracy of the microchromatographic column, the control of the uniformity of the stationary phase coating will affect the separation performance of the system.

[0003] In existing micro gas chromatography, there is a contradiction between the uniformity of the stationary phase coating of the microchromatographic column and the separation capacity. It is difficult to balance the separation efficiency of multi-component samples while maintaining high column efficiency, which restricts the high-precision separation ability of complex organic mixtures. Summary of the Invention

[0004] In order to overcome the above-mentioned defects of the prior art, embodiments of the present invention provide an organic sample analysis method and a chromatograph based on micro gas chromatography to solve the problems raised in the above background art.

[0005] To achieve the above object, the present invention provides the following technical solutions: An organic sample analysis method based on micro gas chromatography, comprising: S1. Continuously pre-flush the carrier gas into the microchromatographic column and collect the pressure waveform to construct an initial profile of the stationary phase distribution; S2. Alternately apply a segmented temperature gradient, a micro negative pressure, and a directional pulsed flow on the basis of the initial profile of the stationary phase distribution to reshape and form a uniform stationary phase distribution layer; S3. Inject a calibration mixture and a trace inert tracer gas pulse into the uniform stationary phase distribution layer to obtain the retention time of the calibration peak and the lag time difference of the tracer gas and generate a set of calibration factors; S4. Dynamically adjust the carrier gas flow rate and temperature program according to the set of calibration factors to establish an operating curve matching the uniform stationary phase distribution layer; S5. Load the organic sample to be measured into the microchromatographic column of the uniform stationary phase distribution layer under the conditions of the operating curve, complete the component separation and record the peak signal in real time; S6. Output the quantitative results of each component according to the corresponding relationship between the peak signal, the peak retention time, and the lag time difference of the tracer gas.

[0006] In a preferred embodiment, continuously pre-flush the micro-column with carrier gas and collect the pressure waveform to construct the initial profile of the stationary phase distribution, including: Stably introduce the carrier gas into the micro-column and set a pressure sensor at the inlet end to obtain continuous pressure data; Process the continuous pressure data through filtering to form a pressure waveform curve; Invert the axial resistance distribution of the stationary phase based on the pressure waveform curve and generate the initial profile of the stationary phase distribution.

[0007] In a preferred embodiment, alternately apply a segmented temperature gradient, a micro-negative pressure, and a directional pulsed flow on the basis of the initial profile of the stationary phase distribution to reshape and form a uniformly distributed stationary phase layer, including: Based on the initial profile of the stationary phase distribution, divide multiple independent temperature zones along the axis of the micro-column, with the temperature gradient difference in each independent temperature zone within a preset range, and apply the temperature in segments through a thin-film heater attached to the outer wall of the chromatographic column; After applying the temperature gradient, connect a vacuum pump to the outlet end of the micro-column to generate a micro-negative pressure, and its pressure range is adapted to the structural strength of the micro-column; During the action of the micro-negative pressure, inject the carrier gas in the form of pulses into the inlet end of the micro-column, and the pulse frequency and duration are adapted to the hydrodynamic characteristics of the carrier gas flow; Alternately execute the application of the temperature gradient, the generation of the micro-negative pressure, and the injection of the pulsed carrier gas, and the number of cycles is adapted to the change trend of the uniformity of the stationary phase coating thickness until the stationary phase coating thickness distribution meets the preset uniformity standard.

[0008] In a preferred embodiment, inject a calibration mixture and a pulse of a trace inert tracer gas into the uniformly distributed stationary phase layer, obtain the retention time of the calibration peak and the lag time difference of the tracer gas, and generate a set of calibration factors, including: Alternately inject the calibration mixture and the inert tracer gas pulse into the uniformly distributed stationary phase layer; Synchronously capture the separation peak shapes of different boiling point components in the calibration mixture and the diffusion peak shape of the tracer gas through a thermal conductivity detector, and extract the vertex time of each separation peak shape and the tailing time of the diffusion peak shape; Based on the time domain difference between the vertex time and the tailing time, combined with the axial temperature distribution data of the uniformly distributed stationary phase layer, construct the diffusion resistance compensation coefficient for each boiling point component; Gradually match the diffusion resistance compensation coefficient with the theoretical values in the standard retention time database to generate a set of calibration factors including the temperature-resistance coupling relationship, and the priority of the gradual matching is sorted according to the polarity difference of the boiling point components.

[0009] In a preferred embodiment, the injection timing of the calibration mixture and the interval of the tracer gas pulse are dynamically adjusted based on the porosity gradient of the uniformly distributed stationary phase layer.

[0010] In a preferred embodiment, the carrier gas flow rate and the temperature program are dynamically adjusted according to the set of calibration factors to establish an operating curve that matches the uniformly distributed stationary phase layer, including: Based on the temperature-resistance coupling relationship in the set of calibration factors, the boiling point components of the sample to be measured are split into two categories, high priority and low priority, according to the polarity priority; For the high-priority components, according to their corresponding diffusion resistance compensation coefficients, the carrier gas flow rate is gradually increased along the axial position of the uniformly distributed stationary phase layer, and the increase amplitude of the flow rate is positively correlated with the compensation coefficient; For the low-priority components, combined with the axial temperature distribution data of the uniformly distributed stationary phase layer, the heating rate range of the temperature program is symmetrically extended with the median value of each temperature gradient; The adjusted carrier gas flow rate and temperature program are recombined according to the elution order of the boiling point components to generate an operating curve including segmented flow rate control instructions and a non-linear temperature gradient. The recombination process ensures that the flow rate and temperature change rates between adjacent segments are continuously differentiable.

[0011] In a preferred embodiment, under the conditions of the operating curve, the organic sample to be measured is loaded onto the microchromatographic column of the uniformly distributed stationary phase layer to complete component separation and record the peak signal in real time, including: The organic sample to be measured is loaded into the inlet of the microchromatographic column through a microliter syringe, and the loading volume is adapted to the adsorption capacity of the uniformly distributed stationary phase layer; According to the segmented flow rate control instructions in the operating curve, the carrier gas flow rate is switched to the target value segment by segment, and the time interval during the switching process matches the theoretical elution time window of the boiling point components; Synchronize the non-linear temperature gradient program in the operating curve to control the temperature rise rate of the thin film heater on the outer wall of the microchromatographic column, and the rate change rate is consistent with the temperature gradient difference between adjacent segments; The separated component peak signals are captured by a thermal conductivity detector, and the peak signals are recorded in real time as a time-voltage waveform. The waveform sampling frequency is adapted to the minimum resolution of the peak shape half-peak width; The recorded peak signals are aligned in time sequence with the theoretical retention times in the set of calibration factors to generate an analyzed peak sequence calibrated on the time axis.

[0012] In a preferred embodiment, according to the corresponding relationship between the peak signal, the peak retention time, and the tracer gas lag time difference, the quantitative results of each component are output, including: Perform baseline correction on the analyzed peak sequence calibrated on the time axis, and calculate the area of each peak of the corrected peak signal through an integration algorithm; Based on the temperature-resistance coupling relationship in the correction factor set, match the theoretical retention time corresponding to each peak with the diffusion resistance compensation coefficient to generate the conversion factor between peak area and concentration; Combine the compensation amount of the peak retention time by the lag time difference of the tracer gas to adjust the time axis alignment error of the conversion factor, and the compensation amount is calculated by the product of the lag time difference and the carrier gas flow rate; Multiply the adjusted conversion factor by the peak area to obtain the concentration values of each component, and sort the concentration values according to the outflow order of the boiling point components and output the quantitative result table.

[0013] On the other hand, the present invention provides a chromatograph for the analysis of organic samples based on micro gas chromatography, including: A carrier gas supply module configured to continuously introduce carrier gas into the micro chromatographic column and connect a pressure sensor at the inlet end to collect continuous pressure waveform data; A stationary phase regulation module configured to alternately apply a segmented temperature gradient, a micro negative pressure, and a pulsed carrier gas flow on the basis of the initial profile of the stationary phase distribution in the micro chromatographic column to reshape and form a uniform stationary phase distribution layer; A correction factor generation module configured to inject a correction mixture and a trace amount of inert tracer gas pulse into the uniform stationary phase distribution layer, obtain the correction peak retention time and the lag time difference of the tracer gas, and generate a correction factor set; A dynamic parameter control module configured to dynamically adjust the carrier gas flow rate and the temperature program according to the correction factor set to establish an operating curve matching the uniform stationary phase distribution layer; A separation and detection module configured to load the organic sample to be measured into the micro chromatographic column under the conditions of the operating curve and record the separated peak signals in real time; A quantitative output module configured to output the quantitative results of each component according to the corresponding relationship between the peak signals, the retention time in the correction factor set, and the lag time difference; A processor and a memory, and the memory stores the correction factor set and the operating curve generation algorithm.

[0014] On the other hand, the processor is configured to perform the following operations: Generate the initial profile of the stationary phase distribution according to the continuous pressure waveform data collected by the pressure sensor; Control the stationary phase regulation module to perform the alternate application operation; Control the correction factor generation module to obtain the retention time and the lag time difference; Control the dynamic parameter control module to generate the operating curve; Control the separation and detection module to record the peak signals; Control the quantitative output module to generate the quantitative results.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. Through the dynamic regulation of the stationary phase coating distribution and the real-time feedback correction mechanism, the present invention significantly improves the separation precision and stability of the micro gas chromatography system. Aiming at the problem of controlling the uniformity of the stationary phase coating on the microchromatography column, the method of alternately applying a segmented temperature gradient and a micro negative pressure is adopted to directionally regulate the physical distribution characteristics of the stationary phase during the flow of the carrier gas, making the coating thickness tend to be consistent at the microscale. Through the synergistic effect of pressure waveform inversion and dynamic parameter adjustment, while ensuring high column efficiency, the separation capacity of the chromatographic column is effectively expanded, enabling components with different boiling points and polarities in complex organic mixtures to achieve high-resolution separation, and solving the problem of decreased selectivity caused by uneven coating distribution in traditional miniaturization processes.

[0016] 2. Based on the correction factor set of the temperature-resistance coupling relationship, the thermodynamic response of the stationary phase is dynamically correlated with the hydrodynamic characteristics. By real-time feedback of the peak signal and the lag time difference data, the system can adaptively adjust the carrier gas flow rate and the temperature control program to maintain the stability of the separation parameters under variable temperature and variable pressure conditions. It effectively suppresses the thermal expansion of the stationary phase coating in the microcolumn and the interference of carrier gas turbulence, making the quantitative analysis results have higher reproducibility and accuracy, especially suitable for the rapid and accurate detection of trace components and wide-boiling-range samples. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a flowchart of the organic sample analysis method based on the micro gas chromatography method of the present invention; Figure 2 is a schematic structural diagram of the chromatograph for the organic sample analysis based on the micro gas chromatography method of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. 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.

[0019] Embodiment 1: Figure 1 An organic sample analysis method based on the micro gas chromatography method of the present invention is given, including the following steps: S1. Continuously pre-flush the carrier gas into the microchromatography column and collect the pressure waveform to construct the initial profile of the stationary phase distribution; S2. Alternately apply a segmented temperature gradient, a micro negative pressure, and a directional pulsed flow on the basis of the initial profile of the stationary phase distribution to reshape and form a uniform stationary phase distribution layer; S3. Inject a calibration mixture and a trace inert tracer gas pulse into the uniform stationary phase distribution layer, obtain the retention time of the calibration peak and the lag time difference of the tracer gas, and generate a calibration factor set; S4. Dynamically adjust the carrier gas flow rate and temperature program according to the correction factor set, and establish an operating curve that matches the uniform distribution layer of the stationary phase; S5. Under the conditions of the operating curve, load the organic sample to be measured onto the microchromatographic column of the uniform distribution layer of the stationary phase, complete the component separation, and record the peak signal in real time; S6. According to the corresponding relationship between the peak signal, the peak retention time, and the lag time difference of the tracer gas, output the quantitative results of each component.

[0020] S1. Continuously pre-flush the carrier gas into the microchromatographic column and collect the pressure waveform to construct the initial profile of the stationary phase distribution. The specific implementation is as follows: Stably introduce the carrier gas into the microchromatographic column and set a pressure sensor at the inlet end to obtain continuous pressure data. The carrier gas is nitrogen or helium with a purity of not less than 99.99%. The range of the introduced flow rate is calculated by Poiseuille's law. For example, according to the ratio of the square of the inner diameter of the microchromatographic column to the viscosity of the carrier gas multiplied by the preset pressure difference, control the flow rate within the range of, for example, 0.5 mL / min to 2.0 mL / min. The preset pressure difference is, for example, 80% of the maximum allowable pressure difference between the inlet end and the outlet end of the microchromatographic column. The maximum allowable pressure difference is set according to the anti-deformation strength of the microchromatographic column material and the pressure-bearing capacity of the sealing structure. For example, the elastic modulus of the stainless steel material is 200 GPa, and the pressure-bearing strength of the fluororubber sealing structure is 10 MPa. The pressure sensor is a piezoresistive microelectromechanical system sensor, installed at the connection between the inlet end of the microchromatographic column and the carrier gas delivery pipeline. The sensor range is, for example, 0 kPa to 100 kPa, and the range is selected according to, for example, 1.5 times the upper limit of the working pressure of the microchromatographic column. The sampling frequency is set to be not less than, for example, 200 Hz. Its setting is based on the Nyquist sampling theorem, satisfying more than 2 times the highest frequency component of the carrier gas pressure fluctuation. For example, when the mechanical pulsation fundamental frequency of the carrier gas pump is 20 Hz, the sampling frequency needs to be greater than 40 Hz. The continuous pressure data takes time as the abscissa and the pressure value as the ordinate, and is converted into a digital signal through an analog-to-digital converter. The number of bits of the analog-to-digital converter is, for example, 16 bits, and the conversion rate is, for example, 1000 times per second, ensuring no distortion of the pressure fluctuation details.

[0021] The continuous pressure data is processed by filtering to form a pressure waveform curve. The filtering process uses a low-pass digital filter with a cut-off frequency of, for example, 50 Hz. The cut-off frequency is set based on, for example, 1.5 times the mechanical pulsation fundamental frequency of the carrier gas delivery pump. For example, when the mechanical pulsation fundamental frequency of the pump is 20 Hz, the cut-off frequency is set to 30 Hz to cover the harmonics. The filtered data is processed in segments in a sliding window manner. The principle for setting the window length is to cover at least two complete pressure fluctuation cycles. For example, the window length is set to 100 ms, and the overlapping rate of adjacent windows is adjusted to, for example, 50% according to the ratio of the window length to the pressure fluctuation cycle. The data within the window is used to generate a smooth curve through cubic spline interpolation, and the density of the interpolation nodes is, for example, one data point per millisecond. The vertical axis of the pressure waveform curve is the normalized pressure value. The normalization method is to divide the original pressure data minus the initial steady-state pressure value by the maximum pressure fluctuation amplitude. The initial steady-state pressure value is the average pressure within, for example, 10 seconds to 20 seconds after introducing the carrier gas. The time window is selected based on the shortest time required for the carrier gas flow to reach a stable state.

[0022] Based on the pressure waveform curve, the axial resistance distribution of the stationary phase is inverted and the initial profile of the stationary phase distribution is generated. The inversion process is based on a modified model of Darcy's law. The input parameters include the filtered pressure waveform curve, the carrier gas flow rate, the carrier gas viscosity, and the inner diameter of the microchromatography column. The carrier gas viscosity is obtained by looking up a table. For example, the lookup data is from the carrier gas physical property parameter database published by the International Standard Chemical Society. The database indexing parameter is the outer wall temperature of the microchromatography column monitored in real time. The temperature monitoring point is on the outer wall surface at the axial center position of the chromatography column, and the accuracy of the temperature sensor is, for example, ±0.1 °C. The modified model divides the microchromatography column into, for example, 100 to 200 equal-length axial microelement segments. The number of microelement segments is set based on the ratio of the total length of the chromatography column to the minimum resolvable coating thickness change range. For example, when the minimum resolvable coating thickness range is 10 μm, the number of microelement segments corresponding to a 1 m total length of the chromatography column is 100 segments. The pressure drop of each microelement segment is determined by iterative calculation. The iterative condition is that the difference in the resistance coefficient of the microelement segment between two adjacent calculations is less than, for example, 0.01%. The setting basis of the difference threshold is, for example, 1 / 10 of the measurement error range of the resistance coefficient. The output result of the axial resistance distribution of the stationary phase is the resistance coefficient corresponding to each axial position. The definition of the resistance coefficient is the product of the stationary phase coating thickness and the carrier gas viscosity divided by the product of the microelement segment length and the column cross-sectional area, with the dimension of pascal seconds per square meter (Pa·s / m²). The initial profile of the stationary phase distribution uses the axial position as the abscissa and the resistance coefficient as the ordinate. After generating discrete data points, a continuous curve is formed through linear interpolation. The resolution of the axial position is set to, for example, 1% of the total length of the microchromatography column. The calculation method of the resolution value is the total length of the chromatography column divided by, for example, 100.

[0023] The axial resistance coefficient of the stationary phase at each axial position in the microchromatography column is obtained by inverting the pressure waveform curve. The axial resistance coefficient represents the impedance degree of the stationary phase coating to the carrier gas flow, and its dimension is Pascal second per square meter (Pa·s / m²). Arrange the axial resistance coefficients in the order of the axial position of the chromatography column to generate an axial resistance coefficient distribution curve. The curve takes the axial position as the abscissa (unit: meter) and the resistance coefficient as the ordinate (unit: Pa·s / m²), and the data is stored as a two-dimensional array containing position-resistance coefficient. The initial profile of the stationary phase distribution is defined as the discretized expression of the axial resistance coefficient distribution curve, which is used to guide the temperature zone division in step S2 and the porosity gradient calculation in step S3.

[0024] S2. Alternately apply a segmented temperature gradient, a micro negative pressure, and a directional pulse flow on the basis of the initial profile of the stationary phase distribution to reshape and form a uniform stationary phase distribution layer. The specific implementation is as follows: Based on the initial profile of the stationary phase distribution, divide multiple independent temperature zones along the axis of the microchromatography column. The temperature gradient difference in each independent temperature zone is within a preset range. The temperature is applied in segments through a thin film heater attached to the outer wall of the chromatography column. The number of independent temperature zones is determined according to the fluctuation range of the resistance coefficient in the initial profile of the stationary phase distribution. For example, when the fluctuation amplitude of the resistance coefficient at the axial position is greater than the preset threshold, the corresponding section is divided into an independent temperature zone. The preset threshold is, for example, 20% of the average value of the resistance coefficient. The preset range of the temperature gradient difference is determined by the temperature resistance limit of the microchromatography column material and the thermal stability of the stationary phase. For example, when the stationary phase is polysiloxane, the upper limit of the temperature gradient difference is set to 200°C to avoid thermal decomposition of the material. The heating power of the thin film heater is calculated according to the length of the temperature zone and the target temperature gradient difference. For example, a temperature zone with a length of 10 cm needs to apply a power of 5 W / cm² to achieve a gradient of 50°C / cm. The heating power is dynamically adjusted by a PID controller, and the PID parameters are calibrated through a step response experiment. The step response experiment includes applying a step voltage to the thin film heater and recording the temperature change curve, and adjusting the proportional coefficient, integral time, and differential time according to the overshoot and stabilization time of the temperature change curve.

[0025] After applying a temperature gradient, a vacuum pump is connected to the outlet end of the microchromatography column to generate a micro-negative pressure, and the pressure range is adapted to the structural strength of the microchromatography column. The pressure range is determined by the elastic deformation limit of the microchromatography column material. For example, the maximum negative pressure allowed for a microchromatography column made of stainless steel is -5 kPa, and the actual working pressure is set to -5 kPa to -0.1 kPa to avoid column collapse or seal failure. The pumping rate of the vacuum pump is matched to the inner cavity volume of the microchromatography column and the target pressure decay time constant. For example, when the inner cavity volume is 1 mL, the pumping rate is set to 10 mL / min, so that the time for the pressure to drop from atmospheric pressure to -5 kPa is 30 seconds. The operating state of the vacuum pump is monitored in real time by a pressure sensor. When the pressure fluctuation amplitude exceeds the set threshold, the pumping rate is automatically adjusted to maintain pressure stability. The set threshold is, for example, ±5% of the pressure fluctuation amplitude.

[0026] During the action of the micro-negative pressure, the carrier gas is injected into the inlet end of the microchromatography column in the form of pulses, and the pulse frequency and duration are adapted to the hydrodynamic characteristics of the carrier gas flow. The pulse frequency is determined by calculating the Reynolds number. For example, when the Reynolds number is less than 2000, the pulse frequency is set to 1 Hz to 5 Hz to avoid the laminar flow state being destroyed. The calculation of the Reynolds number is based on the carrier gas density, flow rate, viscosity, and the inner diameter of the microchromatography column. For example, when the carrier gas density is 1.164 kg / m³, the flow rate is 2 mL / min, the viscosity is 0.01 Pa·s, and the inner diameter is 0.25 mm, the Reynolds number is 150. The pulse duration is adjusted according to the average residence time of the carrier gas in the microchromatography column. For example, when the residence time is 10 seconds, the single pulse duration is set to 0.5 seconds to 1 second to ensure that the pulsed carrier gas covers at least 5% of the column space. The injection of the carrier gas pulse is controlled by a high-speed solenoid valve. The response time of the solenoid valve is less than 10 ms, and the valve opening is linearly adjusted according to the target flow rate. The flow calibration method is to measure the volume change of the carrier gas per unit time under atmospheric pressure. For example, the valve opening corresponding to a flow rate of 1 mL per minute measured by a soap film flowmeter is 30%.

[0027] Alternately perform temperature gradient application, micro-negative pressure generation, and pulsed carrier gas injection. The number of cycles is adapted to the change trend of the uniformity of the stationary phase coating thickness until the stationary phase coating thickness distribution meets the preset uniformity standard. The adjustment of the number of cycles is based on the attenuation rate of the standard deviation of the coating thickness after each cycle. For example, when the standard deviation attenuation rate is less than 5%, the cycle is terminated, and the maximum number of cycles is limited to 10 to avoid over-treatment. The uniformity standard is verified by the off-line detection results of the coating thickness using an optical interferometer or a scanning electron microscope. For example, when the standard deviation of the thickness is less than 1 μm, it is determined to meet the standard. The detection method of the optical interferometer includes cutting the micro-column into several segments, each segment with a length of 1 cm, measuring the coating thickness of each segment, and calculating the standard deviation. When an abnormal temperature or pressure limit is detected during the cycle, a protection mechanism is triggered to pause the process and alarm. The abnormal conditions are, for example, the temperature exceeds the decomposition temperature of the stationary phase by 10 °C or the pressure is lower than -5 kPa. The protection mechanism includes cutting off the power supply of the thin film heater and starting the pressure relief valve to release the negative pressure.

[0028] S3. Inject a calibration mixture and a pulse of trace inert tracer gas into the stationary phase uniform distribution layer, obtain the retention time of the calibration peak and the lag time difference of the tracer gas, and generate a set of calibration factors. The specific implementation is as follows: Inject a calibration mixture and a pulse of inert tracer gas into the stationary phase uniform distribution layer alternately, where the injection timing of the calibration mixture and the interval of the tracer gas pulse are dynamically adjusted based on the porosity gradient of the stationary phase uniform distribution layer. The porosity gradient is calculated from the axial resistance coefficient distribution curve generated in step S1. The calculation formula is that the porosity gradient is equal to the ratio of the difference in resistance coefficients at two adjacent axial positions to the position spacing. For example, when the resistance coefficient is 1.2 Pa·s / m² at position A, 1.5 Pa·s / m² at position B, and the spacing is 0.01 m, the porosity gradient is 30 Pa·s / m³. When the porosity gradient is greater than the preset threshold, the injection interval between the calibration mixture and the tracer gas pulse is shortened. For example, for every 10 Pa·s / m³ increase in the porosity gradient, the interval time is reduced by 5%. The preset threshold is set according to the type of stationary phase material. For example, the threshold for a polysiloxane stationary phase is set to 20 Pa·s / m³, and for a metal-organic framework material (MOF), it is set to 50 Pa·s / m³.

[0029] When the porosity gradient is greater than the preset threshold, shorten the injection interval between the calibration mixture and the tracer gas pulse. For example, for every 0.1 / mm increase in the porosity gradient, the interval time is reduced by 10%. The preset threshold is calculated based on the average pore size of the stationary phase material in the microchromatography column. For example, when the average pore size is 100 nm, the preset threshold is set to 0.05 / mm. The calibration mixture contains target components with a boiling point range covering the sample to be analyzed. For example, the calibration mixture is a C8-C16 n-alkane mixture. The inert tracer gas is selected as argon, which has a significant difference in type from the carrier gas, to ensure signal separation in the thermal conductivity detector. The injection of the calibration mixture and the tracer gas is controlled by a high-speed solenoid valve, and the switching time of the solenoid valve is less than 10 ms. The injection flow rate is adjusted by a mass flow controller, and the flow error is less than ±1%.

[0030] Synchronously capture the separation peak shapes of different boiling point components in the calibration mixture and the diffusion peak shape of the tracer gas through a thermal conductivity detector, and extract the vertex time of each separation peak shape and the tailing time of the diffusion peak shape. The time resolution of the thermal conductivity detector is set to 0.05 seconds to fully capture the peak shape details. The time resolution is determined by the bridge response time of the detector and the bandwidth of the signal amplification circuit. The bridge response time is calculated from the thermal conductivity and heat capacity of the hot wire material. For example, when the thermal conductivity of tungsten wire is 173 W / (m·K) and the heat capacity is 0.13 J / (g·K), the response time is 0.03 seconds. The vertex time is defined as the moment corresponding to the intersection of the point with the maximum slope on the rising edge of the peak shape and the baseline. The point with the maximum slope is calculated by the three-point difference method. For example, when the slope difference between three adjacent data points is less than 0.1%, it is determined as the peak point. The tailing time is defined as the moment when the falling edge of the peak shape reaches 10% of the peak height. The position at 10% of the peak height is determined by linear interpolation. The difference between the vertex time and the tailing time is calculated as the time domain difference. For example, if the vertex time of a certain component is 100 seconds and the tailing time is 110 seconds, the time domain difference is 10 seconds. The calibration method for the baseline is to collect the average value of the steady-state signal for 30 seconds when no sample is injected. The baseline drift compensation is achieved through sliding window averaging filtering, and the window length is 5 seconds.

[0031] Based on the time-domain difference between the vertex time and the tailing time, combined with the axial temperature distribution data of the uniformly distributed layer of the stationary phase, the diffusion resistance compensation coefficient of each boiling point component is constructed. The axial temperature distribution data is sourced from the records of the temperature control unit during the segmented temperature gradient application in step S2, such as the actual temperature values and time-temperature change curves of each independent temperature zone. The time synchronization accuracy of the temperature data is 0.1 second, synchronized with the signal acquisition clock of the thermal conductivity detector. The calculation formula of the diffusion resistance compensation coefficient is expressed as the ratio of the time-domain difference to the temperature gradient at the corresponding axial position. For example, if the time-domain difference is 10 seconds and the temperature gradient in this section is 50 °C / m, the diffusion resistance compensation coefficient is 0.2 second·m / °C. The temperature gradient is calculated by dividing the temperature difference between two adjacent temperature zones by the length of the temperature zone. For example, if the temperature in temperature zone A is 150 °C, the temperature in temperature zone B is 120 °C, and the length of the temperature zone is 0.1 m, then the temperature gradient is 300 °C / m. When the temperature gradient change exceeds the set range, an abnormal temperature data mark is automatically triggered. The set range is, for example, that the temperature difference between adjacent temperature zones exceeds 30 °C. After the abnormal mark is triggered, the calibration process is paused and the temperature calibration program is started. The calibration program includes re-measuring the actual temperature of the temperature zone and updating the axial temperature distribution data.

[0032] The diffusion resistance compensation coefficient is gradually matched with the theoretical values in the standard retention time database to generate a correction factor set containing the temperature-resistance coupling relationship. The priority of the gradual matching is sorted according to the polarity difference of the boiling point components. The standard retention time database is a pre-established data set of the retention times of various compounds under different temperature and stationary phase conditions. For example, the baseline data is generated by testing the retention times of C8-C16 alkanes in a polysiloxane stationary phase. The data acquisition conditions are a carrier gas flow rate of 1 mL / min and a temperature gradient of 50 °C / m. The gradual matching process preferentially processes components with higher polarity, such as compounds containing hydroxyl or carboxylic acid groups. The priority sorting is based on the adsorption energy difference of the components in the stationary phase. The adsorption energy is estimated by the octanol-water partition coefficient (logP value) of the compound, and the logP value is determined by the shake flask method experiment or obtained from the PubChem database. For example, when the logP value is less than 3, it is determined as a high-polarity component and is preferentially matched. The correction factor set is stored in the form of a two-dimensional matrix. The rows of the matrix correspond to the unique identifiers of the boiling point components, and the columns include the diffusion resistance compensation coefficient, the theoretical retention time, and the temperature-resistance coupling coefficient. The matrix data is stored in CSV format, supporting external software calls and visual analysis.

[0033] When the deviation of the diffusion resistance compensation coefficient of a certain component in the calibration mixture from the theoretical value in the database exceeds the allowable threshold, a calibration failure flag is triggered and the injection process is automatically repeated. The allowable threshold is, for example, 10% of the theoretical value. The interval time of the repeated injection process is adjusted according to the thermal stability of the uniform distribution layer of the stationary phase. For example, the maximum number of repetitions for a polysiloxane stationary phase is 5 times, and the interval time for each injection is at least 2 minutes to prevent coating degradation. The calibration failure flag is linked to the dynamic adjustment of the carrier gas flow rate in step S4, and the adjustment range of the flow rate is calculated according to the degree of deviation. For example, for every 5% increase in the deviation, the flow rate is increased by 5%. In extreme cases, such as when the calibration failure is triggered continuously 3 times, the system automatically switches to a standby calibration mixture and sends a maintenance alert. The standby calibration mixture selects components with the same boiling point range but lower polarity, such as a perfluoroalkane mixture.

[0034] S4. Dynamically adjust the carrier gas flow rate and temperature program according to the calibration factor set to establish an operating curve that matches the uniform distribution layer of the stationary phase. The specific implementation is as follows: Based on the temperature-resistance coupling relationship in the calibration factor set, the boiling point components of the sample to be measured are split into two categories: high-priority and low-priority, according to the polarity priority. The polarity priority is divided according to the critical value of the octanol-water partition coefficient set when generating the calibration factor set in step S3. For example, when the logP value of a component is less than 3, it is classified as a high-priority component, and the rest are low-priority components. The temperature-resistance coupling relationship in the calibration factor set is derived from the mapping result of the diffusion resistance compensation coefficient and the theoretical retention time in step S3, and is specifically expressed as the product of the temperature gradient optimization coefficient and the resistance compensation value corresponding to each boiling point component. The product is used to quantify the separation response characteristics of the component under different temperatures and coating resistances. The temperature gradient optimization coefficient is calibrated through the segmented temperature gradient application experiment in step S2. The calibration method is to measure the retention time deviation of the reference component under different temperature gradients and select the coefficient value corresponding to the minimum deviation.

[0035] For high-priority components, according to their corresponding diffusion resistance compensation coefficients, the carrier gas flow rate is gradually increased section by section along the axial position of the uniform distribution layer of the stationary phase. The increase amplitude of the flow rate is positively correlated with the compensation coefficient. The diffusion resistance compensation coefficient is derived from the calculation result of step S3, and its dimension is seconds · meters per degree Celsius (s·m / ℃). The calculation formula is the time domain difference (seconds) divided by the temperature gradient (℃ / m) at the corresponding axial position. For example, when the time domain difference is 10 seconds and the temperature gradient is 50℃ / m, the compensation coefficient is 0.2 s·m / ℃. The calculation method of the increase amplitude of the flow rate is the compensation coefficient multiplied by the adjustment gain coefficient of the base flow rate. The gain coefficient is determined through the separation optimization experiment. For example, when the initial gain coefficient is 0.5, a mixture of benzene and toluene is injected, and when the separation reaches 1.5, it is recorded as the effective gain coefficient. The base flow rate is the reference value of the initial carrier gas flow rate set in step S1. For example, when the initial flow rate is 0.5 mL / min, the upper limit of the adjusted flow rate does not exceed the maximum range of the mass flow controller (for example, 5 mL / min).

[0036] For low-priority components, combined with the axial temperature distribution data of the uniform distribution layer of the stationary phase, the heating rate range of the temperature program is symmetrically expanded with the temperature gradient of each section as the median. The axial temperature distribution data is derived from the historical records of segmented temperature control in step S2. For example, if the preset temperature gradient of a certain temperature zone is 50℃ / m, the expanded heating rate range is set to 40℃ / m to 60℃ / m, and the expansion amplitude is determined based on the actual temperature control accuracy of this temperature zone. For example, when the temperature control accuracy is ±1℃, the expansion amplitude is ±20%. The symmetric expansion is achieved through double-interval linear mapping. The mapping formula is that the expansion lower limit is equal to the median minus the expansion amplitude, and the expansion upper limit is equal to the median plus the expansion amplitude. When the temperature gradient exceeds the glass transition point of the material, the temperature protection mechanism is triggered and the upper limit of the expansion amplitude is locked. For example, when the glass transition temperature of the polysiloxane stationary phase is 300℃, the expansion upper limit is 280℃. The locking logic is that if the current temperature gradient exceeds the upper limit, it will be automatically replaced with the upper limit value.

[0037] Recombine the adjusted carrier gas flow rate and temperature program according to the elution order of boiling point components to generate an operating curve containing segmented flow rate control instructions and a non-linear temperature gradient. The recombination process ensures that the flow rate and temperature change rates between adjacent segments are continuously differentiable. The elution order is predicted by the theoretical data in the standard retention time database in step S3. For example, when the retention time of the main peak is known to be 10 minutes, the start time of the carrier gas flow rate adjustment segment is 9.5 minutes. The flow rate change rate between adjacent segments is constrained by the fluid continuity equation, specifically, the flow rate difference between adjacent time nodes does not exceed 20% of the previous segment's flow rate. For example, when the previous segment's flow rate is 1 mL / min, the maximum adjustment of the adjacent segment's flow rate is 1.2 mL / min. The temperature change rate is restricted by the derivative smoothing algorithm. For example, the difference in temperature slopes between adjacent temperature intervals does not exceed 5 °C / min, and the slope difference is calculated by the three-point difference method with a difference step of 0.1 minute. The recombined operating curve uses time as the horizontal axis and synchronously stores the target value of the carrier gas flow rate and the set value of the temperature. The data format is a multi-column CSV table, which supports import and execution by standard chromatography control software (such as Agilent ChemStation).

[0038] When the parameters in the operating curve exceed the hardware execution capabilities, trigger the adaptive degradation mode. For example, when the applied flow rate exceeds the maximum range of the mass flow controller (such as 5 mL / min), the adaptive degradation mode scales the flow rates of all segments by a proportionality coefficient, which is equal to the maximum range divided by the maximum value of the applied flow rate. For example, when the maximum applied flow rate is 6 mL / min, the proportionality coefficient is 5 / 6 ≈ 0.833, and the flow rates of all segments are multiplied by 0.833 and the column temperature reduction time is scaled synchronously to maintain the separation efficiency. The degraded operating curve generates a log mark and transmits it to the user interface to prompt manual review. In extreme cases, such as when the temperature program exceeds the upper limit tolerated by the heating film (such as 350 °C), the system terminates the analysis process and initiates forced cooling at a rate of 10 °C / min until the temperature returns to the safety threshold (such as 50 °C). During the cooling process, the feedback data of the temperature sensor is monitored in real time. If the cooling rate is insufficient, an auxiliary fan is started for heat dissipation.

[0039] S5. Load the organic sample to be measured onto the microchromatographic column with a uniformly distributed stationary phase layer under the conditions of the operating curve, complete the component separation, and record the peak signal in real time. The specific implementation is as follows: Load the organic sample to be measured into the inlet of the micro-column through a microliter syringe. The loading volume is adapted to the adsorption capacity of the uniformly distributed layer of the stationary phase. The adsorption capacity is calculated based on the coating thickness and surface area of the uniformly distributed layer of the stationary phase in step S2. For example, when the coating thickness is 1 μm and the surface area is 0.5 m² / g, the adsorption capacity is 0.5 μL / mg, and the loading volume is set to 70% of the maximum adsorption capacity to avoid overloading. The injection accuracy of the microliter syringe is ±0.1 μL, and the injection speed is adjusted by the fluid resistance at the inlet end of the micro-column. The fluid resistance is derived from the inversion result of the pressure waveform curve in step S1. For example, when the amplitude of the inlet pressure fluctuation is 5 kPa, the injection speed is controlled at 0.2 μL per second to ensure uniform dispersion of the sample.

[0040] According to the segmented flow rate control instructions in the operation curve, switch the carrier gas flow rate to the target value segment by segment. The time interval of the switching process matches the theoretical elution time window of the boiling point components. The theoretical elution time window is derived from the timing prediction data in the operation curve generated in step S4. The timing prediction data is generated by mapping the correction factor set in step S3 with the theoretical retention time. For example, when the theoretical retention time of a certain component is 10 minutes, the flow rate switching time window is set to 9.5 minutes to 10.5 minutes. The transition time of the flow rate switching is determined according to the step response characteristics of the carrier gas flow controller. The step response characteristics are calibrated through the scaling experiment in the adaptive degradation mode in step S4. For example, when the step response time of the controller is 0.5 s, the transition time is set to 2 s to avoid sudden changes in flow rate. The error range of the target value of the flow controller is less than ±1%, and it is calibrated in real time through the closed-loop proportional integral derivative control algorithm. The parameters of the proportional integral derivative control algorithm are optimized by the temperature control experiment data in step S2.

[0041] Synchronously run the non-linear temperature gradient program in the operation curve to control the temperature rise rate of the thin film heater on the outer wall of the micro-column. The rate of change is consistent with the temperature gradient difference between adjacent segments. The temperature rise rate is calculated based on the ratio of the temperature gradient difference between adjacent segments defined in step S4 to the time interval. For example, when the temperature gradient difference between adjacent segments is 50 °C / m and the time interval is 5 minutes, the temperature rise rate is set to 10 °C / m per minute. The temperature control accuracy of the thin film heater is ±0.5 °C, and the temperature feedback signal is collected by a platinum resistance sensor. The sampling frequency of the platinum resistance sensor is 10 Hz to ensure the capture of temperature fluctuation details. When the deviation between the actual temperature and the target value exceeds 2 °C, trigger the temperature compensation mechanism. The compensation amount is the integral cumulative amount of the deviation value. The integral time constant is calibrated to 30 s through the segmented temperature gradient experiment in step S2.

[0042] The separated component peak signals are captured by a thermal conductivity detector, and the peak signals are recorded in real time as time-voltage waveforms. The waveform sampling frequency is adapted to the minimum resolution of the peak shape at half height. The bridge excitation voltage of the thermal conductivity detector is 5 volts, the signal amplification factor is 1000 times, and the noise level is less than 1 microvolt. The noise level is verified by the baseline calibration data in step S1. The minimum resolution of the peak shape at half height is determined by the Nyquist sampling theorem. For example, when the minimum peak width at half height is 2 seconds, the sampling frequency is at least 10 Hz to ensure that each peak shape contains 20 data points. The baseline calibration method is to collect the average value of the steady-state signal for 60 seconds without sample injection. The baseline drift compensation is achieved by sliding window averaging filtering. The window length is 10 seconds and the overlap rate is 50%. The filtering parameters are optimized by the peak shape data of the calibration mixture in step S3.

[0043] The recorded peak signals are aligned with the theoretical retention times in the correction factor set in time sequence to generate a peak sequence to be analyzed after time axis calibration. The time sequence alignment is achieved by the linear interpolation method. The node spacing of the linear interpolation method is adjusted according to the time sequence prediction accuracy in the running curve of step S4. For example, when the prediction error of the theoretical retention time is 0.3 seconds, the node spacing is set to 0.1 seconds. The aligned peak sequence is stored as a three-column data matrix of time-voltage-temperature, and the data format is a comma-separated value file, which supports import by third-party analysis software. If peak shape overlap or baseline drift exceeding the threshold is detected during the alignment process, the peak splitting algorithm is triggered for processing. The peak splitting threshold is set such that the slope change rate at 10% of the peak height exceeds 5% per second. The slope change rate is calculated by the three-point difference method, and the difference step is 0.05 seconds.

[0044] When a delay in carrier gas flow rate switching or a temperature overlimit is detected, an adaptive error correction mechanism is triggered. For example, when the flow rate switching delay exceeds 20% of the theoretical time window, the duration of the current flow rate segment is automatically extended to the starting point of the next window, and the timing parameters of the subsequent segments are recalculated. The calculation logic of the timing parameters is the same as the running curve generation algorithm in step S4. When the temperature exceeds the limit, if the deviation duration exceeds 30 seconds, the analysis process is paused and a gradient cooling program is started. The cooling rate is 5 degrees Celsius per minute until the temperature returns to the safe range. The safe range is set according to the thermal stability of the stationary phase in step S2. For example, the upper safety temperature limit of the polysiloxane stationary phase is 280 degrees Celsius. The error correction log is recorded in real time and transmitted to the user terminal. The log includes the timestamp, the type of anomaly, and the handling measures. The log format is compatible with the running curve data in step S4.

[0045] S6. Output the quantitative results of each component according to the corresponding relationship between the peak signal, the peak retention time, and the lag time difference of the tracer gas. The specific implementation is as follows: Perform baseline correction on the peak sequence to be analyzed after time axis calibration, and calculate the area of each peak for the corrected peak signal through the integration algorithm. The baseline correction adopts the sliding window average filtering method. The length of the sliding window is determined by twice the full width at half maximum (FWHM) of the peak shape. For example, when the FWHM is 5 seconds, the window length is 10 seconds, and the overlap rate between windows is 50%. The filtered baseline is fitted to the peak valley points by the least squares method. The peak valley points are defined as the positions where the signal values on both sides of the peak shape are first lower than 5% of the peak height. The fitting residual threshold is set to 1% of the peak height. For example, when the peak height is 1000 mV, the residual threshold is 10 mV. When the residual exceeds the threshold, a peak shape distortion mark is triggered and the peak signal recording process in step S5 is re-executed. The integration algorithm is the trapezoidal method, and the integration interval is from the peak start point to the peak end point. The determination conditions for the peak start and end points are that the signal value reaches 5% of the peak height. The integration result is stored as a peak area - time correspondence table, and the data format is a two-column comma-separated value file, which is compatible with the output data of step S5.

[0046] Based on the temperature - resistance coupling relationship in the correction factor set, match the theoretical retention time and diffusion resistance compensation coefficient corresponding to each peak to generate a conversion factor between peak area and concentration. The temperature - resistance coupling relationship is derived from the mapping data of the diffusion resistance compensation coefficient and the theoretical retention time in step S3. The diffusion resistance compensation coefficient is calculated by the ratio of the time domain difference to the temperature gradient in step S3. For example, when the time domain difference is 10 seconds and the temperature gradient is 50 degrees Celsius per meter, the diffusion resistance compensation coefficient is 0.2 seconds·meter per degree Celsius. The calculation formula for the conversion factor is the peak area divided by the product of the diffusion resistance compensation coefficient and the theoretical retention time. For example, when the peak area is 1000 mV·s and the theoretical retention time is 600 seconds, the conversion factor is 1000 / (0.2×600) = 8.33. The matching process is controlled by the time axis alignment error tolerance. The time axis alignment error tolerance is set to 0.5% of the theoretical retention time. For example, when the theoretical retention time is 600 seconds, the tolerance is 3 seconds. When the deviation of the actual retention time exceeds 3 seconds, it is determined that the matching fails and the correction factor set update process in step S3 is triggered.

[0047] Adjust the time-axis alignment error of the conversion factor by combining the compensation amount of the peak retention time for the tracer gas lag time difference. The compensation amount is calculated by multiplying the lag time difference by the carrier gas flow rate. The lag time difference comes from the time-domain difference between the peak vertex of the tracer gas and the peak vertex of the calibration mixture in step S3. For example, the time-domain difference is 2 seconds. The carrier gas flow rate comes from the segmented flow rate target value in the operation curve generated in step S4. For example, the target value is 1 milliliter per minute. The calculation method of the compensation amount is the ratio of the lag time difference to the carrier gas flow rate. For example, 2 seconds / (1 mL / min) = 120 seconds·min / mL, and it is adjusted to a dimensionless scaling factor through a unit conversion coefficient. For example, when the carrier gas flow rate is 1 mL / min, the scaling factor is 2 seconds / (1 mL / min × 60 seconds / min) = 0.033. The adjustment method for the time-axis alignment error is to multiply the conversion factor by the reciprocal of the scaling factor. For example, when the conversion factor is 8.33, the adjusted conversion factor is 8.33 × (1 / 0.033) = 252.4. When the scaling factor exceeds the preset threshold, for example, exceeding 10% of the peak volume, it is determined that the flow rate control is abnormal and the operation curve regeneration process of step S4 is triggered.

[0048] Multiply the adjusted conversion factor by the peak area to obtain the concentration values of each component. The concentration values are sorted according to the elution order of the boiling point components and the quantitative result table is output. The calculation formula for the concentration value is that the concentration is equal to the peak area multiplied by the conversion factor. For example, when the peak area is 1000 mV·s and the conversion factor is 252.4, the concentration is 1000 × 252.4 = 252400 ppm. The sorting logic is based on the component elution order in the operation curve of step S4. For example, the low-boiling point components elute first corresponding to the first row of the table. The quantitative result table includes the component name, retention time, concentration value, and error range. The error range is calculated through the confidence interval of the calibration factor set in step S3. The confidence interval is determined according to the standard deviation of multiple calibration experiments. For example, when the confidence level is 95%, the error range is ±2.5%. The result table is exported as a comma-separated value file, which is compatible with the data matrix format of step S5 and supports direct import by third-party analysis software (such as Agilent MassHunter) to generate a detection report.

[0049] When an abnormal conversion factor or a concentration value exceeding the range is detected, a concentration calibration rollback mechanism is triggered. For example, when the conversion factor exceeds the preset upper limit (e.g., 500), the most recent valid set of correction factors in step S3 is automatically called for recalculation. If the rollback fails three times in a row, the process is aborted and manual intervention is prompted. When the concentration value exceeds the range, the dilution factor is dynamically adjusted according to the loading volume data in step S5. For example, when the initial loading volume is 0.5 microliters, the dilution factor is set to 2 and the concentration is recalculated. The adjustment range of the dilution factor does not exceed 10 times the initial value to avoid distortion. The calibration log records all abnormal events and handling measures. The log format is the same as the error correction log in step S5, including timestamp, abnormal type, handling parameters, and result status. The log file is stored in the standard JSON format for easy traceability analysis.

[0050] In this embodiment, a multi-step collaborative mechanism is used to break through the static regulation limitations of traditional chromatographic separation. In the initial profile construction stage of the stationary phase, through the coupled design of pressure waveform inversion and dynamic application of temperature gradient, the non-linear interference of the coating distribution in the microchromatographic column is overcome. In the separation parameter optimization stage, the temperature-resistance coupling relationship of the correction factor set, the carrier gas flow rate, and the temperature program are recombined into a non-linear operating curve to achieve the dynamic matching of the thermodynamics and hydrodynamics responses of the stationary phase. In the real-time separation and quantification stage, through the linked feedback of lag time difference compensation and baseline drift correction, the cumulative error problems of signal drift and retention time offset in miniaturized devices are solved. The data transfer between steps forms a closed-loop logic. For example, the correction factor set is generated based on the stationary phase distribution parameters and inversely restricts the dynamic adjustment range of the operating curve, while the peak signals recorded in real-time provide verification data for the iterative update of the correction factor set. This multi-parameter cross-correction mechanism cannot be derived through conventional sequential optimization.

[0051] Embodiment 2: Figure 2 A structural schematic diagram of a chromatograph for organic sample analysis based on micro gas chromatography according to the present invention is given. The chromatograph for organic sample analysis based on micro gas chromatography includes: A carrier gas supply module configured to continuously introduce carrier gas into the microchromatographic column and connect a pressure sensor at the inlet end to collect continuous pressure waveform data; A stationary phase regulation module configured to alternately apply segmented temperature gradients, micro negative pressure, and pulsed carrier gas flow on the basis of the initial profile of the stationary phase distribution in the microchromatographic column to reshape and form a uniform stationary phase distribution layer; A correction factor generation module configured to inject a correction mixture and a trace amount of inert tracer gas pulse into the uniform stationary phase distribution layer, obtain the retention time of the correction peak and the lag time difference of the tracer gas, and generate a set of correction factors; A dynamic parameter control module configured to dynamically adjust the carrier gas flow rate and temperature program according to the set of correction factors and establish an operating curve that matches the uniform stationary phase distribution layer; A separation detection module, configured to load an organic sample to be tested onto a microchromatographic column under operating curve conditions and record the peak signals after separation in real time; A quantitative output module, configured to output the quantitative results of each component according to the corresponding relationship between the peak signals and the retention times and lag time differences in the correction factor set; A processor and a memory, the memory stores a correction factor set and an operating curve generation algorithm, and the processor is configured to perform the following operations: Generate an initial profile of the stationary phase distribution based on the continuous pressure waveform data collected by the pressure sensor; Control the stationary phase regulation module to perform an alternating application operation; Control the correction factor generation module to obtain the retention time and the lag time difference; Control the dynamic parameter control module to generate an operating curve; Control the separation detection module to record the peak signals; Control the quantitative output module to generate quantitative results.

[0052] Among them, the carrier gas supply module continuously supplies nitrogen or helium to the microchromatographic column through a mass flow controller, with a flow rate range of 0.5 - 5 mL / min. The pressure sensor uses the Honeywell ABP2 series, with a measuring range of 0 - 100 kPa and a sampling frequency of 200 Hz. The collected continuous pressure waveform data generates an initial profile of the stationary phase distribution through the Darcy's law inversion algorithm. The stationary phase regulation module includes a Kapton film heater array attached to the outer wall of the chromatographic column, with a temperature control range of 50 - 300 °C and an accuracy of ±0.5 °C. The vacuum pump is connected to the outlet end of the chromatographic column to generate a micro negative pressure of -5 kPa to -0.1 kPa. The pulsed carrier gas flow is controlled by a Lee Company LF series high-speed solenoid valve, and the single pulse duration is 0.1 - 1 second. The correction factor generation module injects a C8 - C16 n-alkane correction mixture and a helium tracer pulse into the stationary phase uniform distribution layer. The thermal conductivity detector records the correction peak retention time and the lag time difference with a time resolution of 0.05 seconds to generate a correction factor set including the temperature - resistance coupling relationship. The dynamic parameter control module adjusts the carrier gas flow rate and the temperature program according to the correction factor set to generate a segmented flow rate command (0.5 - 5 mL / min) and a non-linear temperature gradient (the temperature difference between adjacent segments ≤ 50 °C). The separation detection module loads the sample to be tested under operating curve conditions, records the peak signals in real time, and eliminates the baseline drift through sliding window average filtering. The quantitative output module multiplies the peak area by the conversion factor to generate a concentration value and outputs a result table in CSV format, including the component name, the retention time, and the error range (±2.5%). The processor executes the control logic through an STM32F7 series microcontroller, and the memory uses FLASH to store the correction factor set and the operating curve. The exception handling includes triggering a gradient cooling (5 °C / min) when the temperature exceeds the limit and scaling the instruction ratio when the flow rate exceeds the limit.

[0053] The calculations involved in the embodiments are all dimensionless and take their numerical values for calculation. The preset parameters and threshold selections in the calculations are set by those skilled in the art according to the actual situation.

[0054] It should be noted that the present invention can be deployed on the device itself to achieve embedded applications, or can also run on a PC or other terminals with a user interface, so as to meet various hardware environments and usage requirements.

[0055] The above embodiments can be implemented in whole or in part by software, hardware, firmware, or any other combination. When implemented using software, the above embodiments can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer programs are loaded or executed on a computer, the processes or functions described in the embodiments of the present application are generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center by wire (such as infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that the computer can access, or a data storage device such as a server or data center that contains one or more collections of available media. The available media can be magnetic media (such as floppy disks, hard disks, magnetic tapes), optical media (such as DVDs), or semiconductor media. The semiconductor media can be a solid-state drive.

[0056] Those skilled in the art can clearly understand that for the convenience and simplicity of description, the specific working processes of the systems, devices, and modules described above can refer to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0057] In several embodiments provided in the present application, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the modules is only a logical function division, and there can be other division methods in actual implementation. For example, multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed mutual coupling or direct coupling or communication connection can be through some interfaces, and the indirect coupling or communication connection of the devices or modules can be in an electrical, mechanical, or other form.

[0058] The module described as a separation component may or may not be physically separated. The component shown as a module may or may not be a physical module. It may be located in one place or distributed across multiple network modules. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0059] In addition, in each embodiment of the present application, each functional module can be integrated into a processing module, or each module can exist physically alone, or two or more modules can be integrated into one module.

[0060] If the above-mentioned function is implemented in the form of a software functional module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, in essence, or the part that contributes to the prior art, or a part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in each embodiment of the present application. The foregoing storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical discs that can store program codes.

[0061] As described above, this is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed in the present application can easily think of changes or substitutions, which should all be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

[0062] Finally: The above description is only the preferred embodiment of the present invention and is not used to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An analytical method for organic samples based on micro gas chromatography, characterized in that, Including: S1. Continuously pre-flush the carrier gas into the microchromatographic column and collect the pressure waveform to construct the initial profile of the stationary phase distribution; S2. Alternately apply a segmented temperature gradient, a micro-negative pressure, and a directional pulsed flow on the basis of the initial profile of the stationary phase distribution to reshape and form a uniform stationary phase distribution layer; S3. Inject a calibration mixture and a pulse of trace inert tracer gas into the uniform stationary phase distribution layer, obtain the retention time of the calibration peak and the lag time difference of the tracer gas, and generate a set of calibration factors; S4. Dynamically adjust the carrier gas flow rate and temperature program according to the set of calibration factors to establish an operating curve matching the uniform stationary phase distribution layer; S5. Load the organic sample to be measured onto the microchromatographic column with a uniform stationary phase distribution layer under the conditions of the operating curve, complete the component separation, and record the peak signal in real time; S6. Output the quantitative results of each component according to the corresponding relationship between the peak signal, the peak retention time, and the lag time difference of the tracer gas.

2. The organic sample analysis method based on micro gas chromatography according to claim 1, characterized in that, Continuously pre-flush the carrier gas into the microchromatographic column and collect the pressure waveform to construct the initial profile of the stationary phase distribution, including: Stably introduce the carrier gas into the microchromatographic column and set a pressure sensor at the inlet end to obtain continuous pressure data; Process the continuous pressure data through filtering to form a pressure waveform curve; Invert the axial resistance distribution of the stationary phase based on the pressure waveform curve and generate the initial profile of the stationary phase distribution.

3. The organic sample analysis method based on micro gas chromatography according to claim 2, wherein Alternately apply a segmented temperature gradient, a micro-negative pressure, and a directional pulsed flow on the basis of the initial profile of the stationary phase distribution to reshape and form a uniform stationary phase distribution layer, including: Based on the initial profile of the stationary phase distribution, divide multiple independent temperature zones along the axis of the microchromatographic column. The temperature gradient difference of each independent temperature zone is within a preset range, and the temperature is applied in segments through a thin film heater attached to the outer wall of the chromatographic column; After applying the temperature gradient, connect a vacuum pump to the outlet end of the microchromatographic column to generate a micro-negative pressure, and its pressure range is adapted to the structural strength of the microchromatographic column; During the action of the micro-negative pressure, inject the carrier gas into the inlet end of the microchromatographic column in the form of a pulse, and the pulse frequency and duration are adapted to the hydrodynamic characteristics of the carrier gas flow; Alternately execute the application of the temperature gradient, the generation of the micro-negative pressure, and the injection of the pulsed carrier gas. The number of cycles is adapted to the change trend of the uniformity of the stationary phase coating thickness distribution until the stationary phase coating thickness distribution meets the preset uniformity standard.

4. The organic sample analysis method based on micro gas chromatography according to claim 3, characterized in that, Inject a calibration mixture and a pulse of trace inert tracer gas into the uniform stationary phase distribution layer, obtain the retention time of the calibration peak and the lag time difference of the tracer gas, and generate a set of calibration factors, including: Alternately inject a calibration mixture and an inert tracer gas pulse into the uniform stationary phase distribution layer; Synchronously capture the separation peak shapes of different boiling point components in the calibration mixture and the diffusion peak shape of the tracer gas through a thermal conductivity detector, and extract the vertex time of each separation peak shape and the trailing time of the diffusion peak shape; Based on the time domain difference between the vertex time and the trailing time, combined with the axial temperature distribution data of the uniform stationary phase distribution layer, construct the diffusion resistance compensation coefficient of each boiling point component; Gradually match the diffusion resistance compensation coefficient with the theoretical value in the standard retention time database to generate a set of calibration factors including the temperature-resistance coupling relationship. The priority of the gradual matching is sorted according to the polarity difference of the boiling point components.

5. The organic sample analysis method based on micro gas chromatography according to claim 4, characterized in that, The injection timing of the calibration mixture and the interval of the tracer gas pulses are dynamically adjusted based on the porosity gradient of the uniform stationary phase distribution layer.

6. The organic sample analysis method based on micro gas chromatography according to claim 4, characterized in that, Dynamically adjust the carrier gas flow rate and temperature program according to the calibration factor set, and establish an operating curve that matches the uniform stationary phase distribution layer, including: Based on the temperature-resistance coupling relationship in the calibration factor set, split the boiling point components of the sample to be measured into two categories, high priority and low priority, according to the polarity priority; For the high-priority components, according to their corresponding diffusion resistance compensation coefficients, gradually increase the carrier gas flow rate along the axial position of the uniform stationary phase distribution layer, and the increase amplitude of the flow rate is positively correlated with the compensation coefficient; For the low-priority components, combine the axial temperature distribution data of the uniform stationary phase distribution layer, and use the temperature gradient of each segment as the median to symmetrically expand the heating rate range of the temperature program; Recombine the adjusted carrier gas flow rate and temperature program according to the elution order of the boiling point components to generate an operating curve including segmented flow rate control instructions and non-linear temperature gradients. The recombination process ensures that the flow rate and temperature change rates between adjacent segments are continuously differentiable.

7. The method for analyzing organic samples based on micro gas chromatography according to claim 6, characterized in that, Under the conditions of the operating curve, load the organic sample to be measured into the microchromatographic column of the uniform stationary phase distribution layer, complete component separation and record the peak signal in real time, including: Load the organic sample to be measured into the inlet of the microchromatographic column through a microliter syringe, and the loading volume is adapted to the adsorption capacity of the uniform stationary phase distribution layer; According to the segmented flow rate control instructions in the operating curve, gradually switch the carrier gas flow rate to the target value, and the time interval during the switching process matches the theoretical elution time window of the boiling point components; Synchronize the non-linear temperature gradient program in the operating curve, and control the temperature rise rate of the thin film heater on the outer wall of the microchromatographic column. The rate of change is consistent with the temperature gradient difference between adjacent segments; Capture the separated component peak signals through a thermal conductivity detector, and record the peak signals in real time as time-voltage waveforms. The waveform sampling frequency is adapted to the minimum resolution of the peak shape at half peak width; Align the recorded peak signals with the theoretical retention times in the calibration factor set to generate an analyzed peak sequence calibrated on the time axis.

8. The method for analyzing organic samples based on micro gas chromatography according to claim 7, characterized in that, According to the corresponding relationship between the peak signal, peak retention time and tracer gas lag time difference, output the quantitative results of each component, including: Perform baseline correction on the analyzed peak sequence calibrated on the time axis, and calculate the area of each peak through the integral algorithm for the corrected peak signals; Based on the temperature-resistance coupling relationship in the calibration factor set, match the theoretical retention time and diffusion resistance compensation coefficient corresponding to each peak to generate a conversion factor between peak area and concentration; Combine the compensation amount of the peak retention time by the tracer gas lag time difference to adjust the time axis alignment error of the conversion factor. The compensation amount is calculated by the product of the lag time difference and the carrier gas flow rate; Multiply the adjusted conversion factor by the peak area to obtain the concentration values of each component. The concentration values are sorted according to the elution order of the boiling point components and a quantitative result table is output.

9. A chromatograph for the analysis of organic samples based on micro gas chromatography, which is used to implement the method for the analysis of organic samples based on micro gas chromatography according to any one of claims 1-8, characterized in that, Including: A carrier gas supply module configured to continuously introduce carrier gas into the microchromatographic column and connect a pressure sensor at the inlet end to collect continuous pressure waveform data; A stationary phase regulation module configured to alternately apply segmented temperature gradients, micro-negative pressures and pulsed carrier gas flows on the basis of the initial profile of the stationary phase distribution in the microchromatographic column to reshape and form a uniform stationary phase distribution layer; A correction factor generation module, configured to inject a correction mixture and a trace inert tracer gas pulse into the stationary phase uniform distribution layer, obtain the retention time of the correction peak and the lag time difference of the tracer gas, and generate a set of correction factors; A dynamic parameter control module, configured to dynamically adjust the carrier gas flow rate and temperature program according to the set of correction factors, and establish an operating curve matching the stationary phase uniform distribution layer; A separation and detection module, configured to load the organic sample to be measured onto the microchromatographic column under the conditions of the operating curve, and record the peak signal after separation in real time; A quantitative output module, configured to output the quantitative results of each component according to the corresponding relationship between the peak signal and the retention time and lag time difference in the set of correction factors; A processor and a memory, where the memory stores the set of correction factors and the operating curve generation algorithm.

10. The chromatograph for organic sample analysis based on micro gas chromatography according to claim 9, characterized in that, The processor is configured to perform the following operations: Generate an initial profile of the stationary phase distribution based on the continuous pressure waveform data collected by the pressure sensor; Control the stationary phase regulation module to perform an alternating application operation; Control the correction factor generation module to obtain the retention time and lag time difference; Control the dynamic parameter control module to generate an operating curve; Control the separation and detection module to record the peak signal; Control the quantitative output module to generate quantitative results.

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