A method for rapidly acquiring transient spectra by high-speed rotating spectroscopic devices with a single detector

Abstract

The present disclosure relates to the technical field of optical analysis, and specifically provides a method for rapidly obtaining transient spectrum by high-speed rotating spectrometer with single detector. The method is characterized in that: the incident light is subjected to different wavelength of emergent light by high-speed rotating spectrometer, and the emergent light is read by single detector in turn and processed by computer to obtain transient spectrum, and the single spectrum acquisition time is less than 0.12 seconds. The method comprises the following steps: 1) guiding the light beam of incident light source into the rotating disc through the incident slit, and decomposing the light beam into spectrum by the spectrometer on the disc; 2) rotating the spectrometer on the disc at high speed, so that the different wavelength of light photons after spectrometer are in turn passed through the emergent slit and enter the single detector; 3) converting the light signal read by the detector into electric signal, and obtaining the transient spectrum after collecting and processing by the computer. The method can be used for online analysis of the components and concentration changes of the effluent of chromatographic column and the components in reaction cell, and solves the problem of slow scanning spectrum speed of existing single detector and over-expensive multi-point detector.

Description

Technical Field

[0001] This disclosure relates to the field of optical analysis technology, specifically providing a method for rapidly acquiring transient spectra using a single detector and a high-speed rotating spectrometer. Background Technology

[0002] The statements herein are provided only as background information in connection with this disclosure and do not necessarily constitute prior art.

[0003] Emission or absorption spectra of matter can be used to detect its elemental and chemical composition, and even the elements and molecules contained in distant celestial bodies. Commonly used spectra in analytical chemistry include ultraviolet spectroscopy, visible spectroscopy, infrared spectroscopy, and Raman spectroscopy. However, current spectral scanning techniques are slow; for example, the scanning resolution for infrared spectroscopy is only 4... At that time, for the common mid-infrared region 400 ~4000 The scanning range requires one to several seconds to obtain a single spectrum. Such a scanning time is feasible for samples with good stability and unchanged composition. However, it is too long for certain applications where components change over time. For example, in the catalytic oxidation and decomposition of organic matter, the components in the sample and their concentrations change significantly over time; research on the dynamic mechanisms of catalytic degradation of organic pollutants requires a method to rapidly obtain transient spectra. Similarly, the analysis of the components in chromatographic column effluent also requires a method to rapidly obtain transient spectra to detect the components and concentrations in the effluent online for qualitative or quantitative analysis. Existing analyses of reaction cells and chromatographic effluents measure overall absorbance or are performed at a fixed wavelength, failing to rapidly obtain comprehensive spectral information. For instance, when using chemiluminescence or electrochemiluminescence to analyze components in the reaction cell, a single photomultiplier tube (PMT) is typically used to detect the overall light signal, and then information such as sample concentration is analyzed based on changes in the light signal over time and comparisons with the spectra of standard substances. When analyzing the composition and concentration changes of a sample over time, a method for rapidly obtaining transient spectra provides richer information than simply detecting changes in total light intensity or light intensity at a specific wavelength. This information helps in analyzing the patterns of change in the components and their concentrations within the sample. Therefore, developing a method for rapidly obtaining transient spectra is essential.

[0004] To acquire transient spectra, existing techniques employ statically deployed charge-coupled devices (CCDs) or complementary metal-oxide-semiconductor (CMOS) arrays with multiple points to read the entire spectrum at once, similar to a digital camera taking a picture of an object. Taking highly sensitive CCDs capable of detecting weak light as an example, liquid nitrogen cooling is required to achieve a low signal-to-noise ratio, making the method expensive and maintenance cumbersome, thus limiting its widespread adoption. To reduce costs, cheaper single-point detectors (SMTs) are needed to replace CCD arrays. Commonly used SMTs include PMTs and photodiodes (APDs). For example, PMTs, with their extremely high sensitivity and ultrafast time response, can detect weak, fleeting light signals. Multi-parameter measurement has always been a challenge for SMTs. To overcome this limitation, multiple lasers can be individually activated to change the excitation wavelength, or filters can be used to change the detection wavelength, employing frequency division multiplexing to operate a single sensor instead of multiple sensors. However, this technique still cannot scan or detect transient spectra. This disclosure employs a spectrometer to decompose the incident light source into a spectrum. Then, by rotating the spectrometer at high speed, photons of different wavelengths in the spectrum are sequentially passed through a slit into a single detector, where optical signals of different wavelengths are converted into electrical signals and recorded, thereby obtaining a transient spectrum.

[0005] The instantaneous spectrum of the incident light signal may change over time, and this change can be used to analyze variations in sample components and their concentrations. Therefore, reducing the acquisition time of the spectrum by a single detector is crucial. PMTs have response times in the nanosecond range; for example, the Hamamatsu R7205-01 has a response time of 26 ns. Therefore, theoretically, over 30 million light signals can be recorded within 1 second. For infrared spectroscopy (600–4000), this is applicable. The scanning range, according to 1 At a given resolution, approximately 4000 light signals are needed for one spectrum. Therefore, the aforementioned PMT model can record a maximum of about 9600 infrared spectra in 1 second. With technological advancements, PMT response times will decrease further; for example, the Hamamatsu R3809U50 has a response time as low as 0.55 ns. The maximum number of infrared spectra mentioned above is also limited by the signal acquisition and storage speed. Taking the commonly used CHI600E electrochemical workstation as an example, its fast data acquisition system can acquire the PMT output signal at a rate of 1 million points / second, thus reducing the maximum number of infrared spectra to 250 spectra / second. During rotation, light signals do not always enter the PMT detector; sometimes it is in a signal-free waiting state. That is, only a certain proportion of time (let's assume this proportion is P) is for spectrum recording, and the rest is the idle time for one rotation. Therefore, the maximum motor speed is 250P rpm. The range of P is generally between 5% and 50%. Assuming the detection time accounts for P = 10%, the maximum motor speed is limited by the signal acquisition speed, which is 25 revolutions per second, equivalent to 1500 revolutions per minute (rpm). The dividing line between high and low speed rotation is generally considered to be 400-500 rpm. Here, we take >500 rpm as high speed, therefore 1500 rpm is considered high speed rotation, and acquiring a complete transient spectrum at this speed requires only 0.04 seconds. Even at a speed of 500 rpm, the transient spectrum acquisition time is 0.12 seconds, which is far less than the spectral acquisition time of ordinary Fourier transform infrared spectroscopy (FTIR).

[0006] The core technology of this disclosure utilizes the high-speed rotation of a beam splitter to sequentially read the split photons by a single detector, recording transient spectral information in real time. This allows for rapid acquisition of transient spectra using a low-cost single detector instead of an expensive multi-point detection array. The technical solution involves first guiding photons from the incident light source through a slit onto a rotating disk. After being decomposed into a spectrum by the optical components on the disk, rapid rotation causes photons of different wavelengths in the spectrum to sequentially pass through another slit into the single detector. Finally, the electrical signal output from the detector is processed by a computer to obtain the spectrum. Summary of the Invention

[0007] To address the problems of slow scanning speed when using a single detector to acquire transient spectra in existing technologies, and high purchase cost and complex maintenance when using a multi-point detector array, one or more embodiments of this disclosure provide a method for rapidly acquiring transient spectra using a single detector through the high-speed rotation of a spectrometer, comprising the following steps: 1) guiding the beam of the incident light source through an incident slit onto a rotating disk, where it is decomposed into a spectrum by the spectrometer on the disk;

[0008] 2) The high-speed rotation of the beam splitter on the rotating disk causes photons of different wavelengths to pass through the exit slit sequentially and enter the single detector.

[0009] 3) The detector reads the optical signal and converts it into an electrical signal, which is then collected and processed by a computer to obtain the transient spectrum;

[0010] The order of steps 1), 2), and 3) cannot be changed.

[0011] One or more of the above technical solutions have the following advantages or beneficial effects:

[0012] 1) This disclosure enables rapid detection of transient spectra using a single detector. Compared to multi-point detector arrays, it reduces the purchase and maintenance costs of the instrument, helping to lower the cost of acquiring transient spectra and promoting their widespread application. Compared to existing single-detector systems, it is also more cost-effective due to the use of a simpler-constructed and faster-dispersing high-speed rotating system.

[0013] 2) This disclosure uses a high-speed motor with uniform rotation to drive the spectrometer. The wavelength of the spectrometer is controlled and determined by adjusting the rotation angle of the rotary table, replacing the stepper motor control of the grating in the spectroscopic scanning process, and replacing the helium-neon laser for accurate positioning and the precision mechanical guide rail for driving the instrument's moving mirror in the infrared spectroscopy scanning process. The method used in this disclosure improves the spectral scanning speed, enabling spectral scanning at low cost and in a very short time, saving significant time and economic costs. Furthermore, it can obtain signals with stronger time resolution, which can be used to analyze the changes in components and their concentrations over time in chromatographic eluates or catalytic reaction tanks. Attached Figure Description

[0014] The accompanying drawings, which form part of this disclosure, are used to provide a further understanding of this disclosure. The illustrative embodiments of this disclosure and their descriptions are used to explain this disclosure and do not constitute an undue limitation of this disclosure.

[0015] Figure 1 This is a schematic diagram of the instrument structure and testing principle of an embodiment of the present invention, in which a single detector PMT is used instead of a multi-point detection array to obtain transient spectra.

[0016] Figure 2 This is a schematic diagram of the overall process and instrument detection principle of Example 1. Detailed Implementation

[0017] The technical solutions in the embodiments of this disclosure will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0018] To address the problems of slow scanning speed when using a single detector to obtain transient spectra in existing technologies, and high purchase cost and complex maintenance when using multi-point detection arrays, this disclosure provides one or more embodiments, such as... Figure 1 As shown, a method is provided for rapidly acquiring transient spectra using a single detector and a high-speed rotating spectrometer. The incident light is decomposed into photons of different wavelengths by the optical device through rotation, which are then read sequentially by the single detector. The transient spectrum is obtained by recording and processing the output signal of the single detector through a computer.

[0019] The light source is incident light, and the light intensity can be controlled by adjusting the width of the slit to ensure that the intensity of the emitted light does not exceed the range of a single detector. The wavelength range of its transient spectrum can be arbitrarily specified, but the materials of the optical components need to be changed to avoid strong absorption of the photons being measured, which could affect the detection of the spectrum.

[0020] The incident slits are either two dot-shaped slits or two cross-shaped linear slits, in order to obtain parallel light for the next step of beam splitting.

[0021] The rotating disk is driven by a high-speed motor with a rotation speed of no less than 500 revolutions per minute. There is a plane reflector on the central axis of the disk. The incident light enters from the axial direction and is reflected by the reflector. After being reflected by the reflector, it enters the spectrometer on the disk in a direction perpendicular to the axial direction (parallel to the disk) and is decomposed into a spectrum.

[0022] In some embodiments of the present invention, the beam-splitting device is a prism and a grating. Multiple mirror reflections or concave or convex lenses are used to diverge the light, thus widening the actual width of the entire spectrum before it enters the detector slit, ensuring that the ratio of the time for recording the spectrum to the time for one rotation is not less than 5%.

[0023] The exit slit in front of the detector is used to adjust the width of the light entering the single detector, thereby changing the wavelength resolution of the transient spectrum.

[0024] In step 1), the beam splitting device is at least one of a prism and a grating.

[0025] In step 2), the rotation speed is not less than 500 rpm.

[0026] In step 3), the collection is performed by the rapid data acquisition system of the electrochemical workstation, which converts the voltage signal into a digital signal; the processing is performed by the computer, which saves the digital signal to a solid-state drive and calculates and plots the transient spectrum.

[0027] Example 1:

[0028] This embodiment provides a method for rapidly acquiring transient spectra using a single detector and a high-speed rotating spectrometer, including the following steps:

[0029] like Figure 2 The effluent after separation by the chromatographic column flows into a dark chamber through a polyethylene tube. Infrared light is emitted through the detection window of the dark chamber, and the emitted light is converted into a signal by a spectrometer and transmitted to a computer. The computer records and processes the data to obtain the transient spectrum. The detection window uses a CaF crystal with a light path length of 100 micrometers. The light source is a nano-infrared light source from Infrasolid, Germany, model HIS550R-OWC.

[0030] The rotating disk inside the spectrometer is driven by a motor at a speed of 1000 rpm. A grating is used for spectral dispersion on the disk, and the spectral collection range is in the mid-infrared region of 400 nm. ~4000 The single detector is a J23 photoconductive InGaAs detector equipped with semiconductor cooling. The output signal of the single detector is acquired by the high-speed data acquisition system of a CHI600E electrochemical workstation with a sampling rate of 1 million points per second, and stored in real-time on a 10TB solid-state drive. The stored data is analyzed by computer software to obtain transient spectra.

[0031] Example 2:

[0032] The transient spectrum of ruthenium terpyridine electrochemiluminescence was recorded using ruthenium terpyridine as the light source. Ruthenium terpyridine was pre-coated onto the surface of a fluorine-doped tin oxide (FTO) electrode, which was then inserted submerged in the electrolyte. A three-electrode system was used in the electrolytic cell, and the input voltage was provided by the CV mode of a Shanghai Chenhua CHI660B electrochemical workstation. The initial input voltage was 0V, the scan range was 0V–1.5V, the scan rate was 0.2V / s, and the current resolution was set to [value missing]. .

[0033] Insert one end of the optical fiber (quartz core and polyacrylate shell, quartz core diameter 1mm) below the surface of the electrolyte, close to the ITO electrode surface, and place the other end at the entrance slit. Start the motor under the disk and adjust the speed to 1100 rpm. Use a quartz prism (5mm thick) on the disk for spectral dispersion, with a spectral collection range of 390nm–780nm in the visible light region.

[0034] The single detector is a Hamamatsu PMTm-h9306_03 PMT, powered by a 4NIC-X18 regulated power supply. The detector's output signal is acquired by the rapid data acquisition system of a CHI600E electrochemical workstation and stored in real-time on a 30TB solid-state drive. The electrolytic cell is placed in one dark box, and the disk and single detector are placed in another dark box, with the two boxes connected by optical fiber.

[0035] Turn on the power to the computer and the single detector, start the CV mode of the electrochemical workstation, and stop data acquisition after 30 minutes. The saved data is analyzed by computer software to obtain transient spectra.

[0036] The above-disclosed embodiments are merely preferred embodiments of this disclosure and should not be construed as limiting the scope of this disclosure. Therefore, any equivalent variations made in accordance with the scope of the patent applications of this disclosure shall still fall within the scope of this disclosure.

Claims

1. A method for rapidly acquiring transient spectra using a single detector and a high-speed rotating spectrometer, characterized in that: After the incident light is split by a high-speed rotating beam splitter, the outgoing light of different wavelengths enters a single detector in sequence and is converted into an electrical signal. After being processed by a computer, the transient spectrum is obtained. Includes the following steps: 1) The beam of light from the incident light source is guided through the incident slit onto the rotating disk, where it is decomposed into a spectrum by the spectrometer on the rotating disk; 2) The high-speed rotation of the beam splitter on the rotating disk causes photons of different wavelengths to pass through the exit slit sequentially and enter the single detector. 3) The optical signal is read by a single detector and converted into an electrical signal, which is then collected and processed by a computer to obtain the transient spectrum; the order of steps 1), 2), and 3) is irreplaceable. The incident slits are either two dot-shaped slits or two cross-shaped linear slits, in order to obtain parallel light for the next step of beam splitting. The rotating disk is driven by a high-speed motor. There is a plane mirror on the central axis of the rotating disk. The incident light enters from the axial direction and is reflected by the mirror. After entering the rotating disk in a direction perpendicular to the axial direction, it is decomposed into a spectrum by the spectrometer. Before the emitted light enters the emission slit in sequence, multiple mirrors are used for reflection or concave lenses or convex mirrors are used to diverge the light, thereby expanding the actual width of the entire spectrum before entering the single detector emission slit, so that the ratio of the time for recording the spectrum to the time for the rotating disk to rotate once is not less than 5%. The optical dispersive device rotates at a speed of more than 500 revolutions per minute, and the transient spectrum acquisition time is less than 0.12 seconds.

2. The method for rapidly acquiring transient spectra using a single detector and a high-speed rotating spectrometer as described in claim 1, characterized in that: In step 1), the beam splitting device is at least one of a prism and a grating.

3. The method for rapidly acquiring transient spectra using a single detector and a high-speed rotating spectrometer as described in claim 1, characterized in that: In step 2), the rotation speed of the spectrometer on the rotating disk is not less than 500 revolutions per minute, and the spectrum is collected at least once for each rotation, with the collection time for a single spectrum being less than 0.12 seconds; the single detector is at least one of a photomultiplier tube and an avalanche photodiode.

4. The method for rapidly acquiring transient spectra using a single detector and a high-speed rotating spectrometer as described in claim 1, characterized in that: In step 3), the collection is performed by the rapid data acquisition system of the electrochemical workstation, which collects the output signal of the single detector and transmits the electrical signal to the computer; the processing is performed by the computer, which saves the electrical signal to the solid-state drive and performs calculations to obtain the transient spectrum.

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