Detection method for monitoring ion mobility spectrometry dopant

Abstract

The invention discloses a detection method for monitoring an ion mobility spectrometry dopant, which adopts an ion mobility spectrometry technology, takes acetone or butanone as the dopant, and detects an impurity signal peak in the dopant acetone or butanone by using a photoionization ion mobility spectrometer; the photoionization ion mobility spectrometer comprises a dopant cylinder, a dopant bottle is arranged in the dopant cylinder, and the dopant bottle is used for releasing acetone or butanone steam; acetone or butanone can be used as a carrier gas and a dopant gas to provide dopant molecules for an ion mobility spectrometer, and can be used as photoionization product reagent ions. The method can monitor the use condition of the dopant in real time, effectively warn that the dopant is about to be used up, remind the dopant to be replaced in time, effectively prevent impurities in the dopant from participating in photoionization and polluting the ion migration tube detector, and the system can realize automatic real-time monitoring and early warning of software.

Description

Technical Field

[0001] The present invention relates to the technical field of analytical chemistry, and more particularly to a detection method for monitoring dopants using ion mobility spectrometry. Background Art

[0002] Acetone (CH3COCH3), also known as dimethyl ketone, is the simplest saturated ketone. It is a colorless, transparent liquid with a distinctive pungent odor. It is readily soluble in water and organic solvents such as methanol, ethanol, ether, chloroform, and pyridine. It is flammable, volatile, and chemically active. Currently, the global industrial production of acetone is primarily based on the cumene process. Acetone is primarily used in industry as a solvent and as an important raw material for synthetic substances. In daily life, it is primarily used for degreasing, dehydration, and fixation.

[0003] Butanone (chemical formula: C4H8O), also known as methyl ethyl ketone, 2-butanone, and MEK for short, is an important organic solvent. It is a colorless, transparent liquid with a fruity or distinctive spicy odor. Butanone is easily soluble in organic solvents such as water, ethanol, ether, acetone, and benzene, and is also miscible with oils. It has high volatility, a boiling point of 79.6°C, and a low flash point (-7°C to -9°C), making it a flammable liquid. In industry, butanone is primarily used in coatings, paints, inks, adhesives, and cleaning agents. As a solvent, it can effectively dissolve resins, pigments, oils, and other substances. It can also serve as an intermediate in organic synthesis, used in the production of chemical products such as vinyl ether, polyurethane, and styrene. In the pharmaceutical industry, butanone can be used in the purification and synthesis of certain drugs. In daily life, butanone can be used in cleaning agents and degreasers, and may also be an ingredient in some nail polish removers and glue removers.

[0004] Ion mobility spectrometry (IMS) is a detection technology developed in the late 1960s. It uses differences in ion migration times to separate and characterize ions, using a concept similar to chromatographic retention time. It was originally called plasma chromatography. Ion mobility spectrometry is a technology for separating and detecting gaseous compounds in mixed analytes. Specific drift times are the basis for separation, requiring the ionized compounds to pass through a fixed distance (drift tube) in a defined electric field. Compared to other technologies such as time-of-flight mass spectrometry, ions migrate relative to an inert drift gas flow at atmospheric pressure. Due to spatial structure slowing and frequent collisions between drift gas molecules, the ion mass and geometric structure determine the drift time of each substance. The principle of photoionization ion mobility spectrometry is a technology that separates and characterizes substances based on the differences in the migration rates of different ions in an electric field.

[0005] Dopants are usually some easily ionized compounds, such as acetone, benzene or toluene, which can generate low-energy photoelectrons under ultraviolet light. These photoelectrons can be adsorbed onto photochemical products in the carrier gas, such as ozone (O3), to form O3 - or its hydrated ions O3(H2O)n. These ions can then react with carbon dioxide (CO2) in the air to produce CO3 - (H2O)n (n=0-3), which can act as a reagent ion to react with the analyte, ionizing the analyte to form product ions. Dopants are an important component in photoionization ion mobility spectrometry, primarily used to improve detection sensitivity and selectivity.

[0006] Chinese patent application number 202310809622.8 discloses an acetone composition, its preparation method, and use. The composition contains an acetone content of at least 99.99%, a total olefin content of less than 1 ppm, a total alcohol content of less than 10 ppm, a total aldehyde content of less than 2 ppm, and a water content of less than 100 ppm. The patent does not cover methods for testing acetone purity.

[0007] Chinese patent application number 202310787821.3 discloses a method for removing acetone from isopropyl alcohol, comprising the following steps: S1. Converting the acetone in isopropyl alcohol into acetone oxime; S2. Distilling the product obtained in step S1. The present invention innovatively proposes to remove acetone from isopropyl alcohol by converting it into acetone oxime, which has a boiling point significantly different from that of isopropyl alcohol. The method of the present invention can effectively remove ppm-level acetone from isopropyl alcohol, with a removal rate of up to 100%. Gas chromatography detection shows that the acetone content is as low as 0 ppm. Conventional distillation, ion exchange, or adsorption methods can then almost completely remove acetone oxime and other impurities, thereby obtaining high-purity electronic-grade isopropyl alcohol. Similarly, the patent does not involve a method for testing the purity of acetone.

[0008] For dopant cartridges without visible windows, when the dopant dosage is unknown and impurity detection has a significant impact on the system and is difficult to recover from, the ion mobility spectrometry dopant detection method of the present invention can monitor and warn in real time that the acetone dopant is about to be exhausted, prompting timely replacement to avoid impurities from participating in photoionization contamination of the detector. Summary of the Invention

[0009] The object of the present invention is to overcome the above-mentioned defects of the prior art and provide a detection method for monitoring ion mobility spectrometry dopants, which can monitor in real time and effectively warn that the acetone or butanone dopant is about to be exhausted, and replace the dopant as soon as possible.

[0010] To achieve the above object, the technical solution of the present invention is as follows:

[0011] A detection method for monitoring dopants by ion mobility spectrometry adopts ion mobility spectrometry technology, uses acetone or butanone as a dopant, and uses a photoionization ion mobility spectrometer to detect impurity signal peaks in the dopant acetone or butanone. The photoionization ion mobility spectrometer includes a dopant cartridge, which is provided with a dopant bottle, and the dopant bottle is used to release acetone or butanone vapor. The acetone or butanone can be used as a carrier gas and a dopant gas to provide dopant molecules to the ion mobility spectrometer as photoionization product reagent ions.

[0012] Optionally, the dopant composition is determined based on the migration time, and the dopant content is determined based on the signal intensity.

[0013] Optionally, the photoionization ion mobility spectrometer includes a dual-position dopant barrel and does not have a visual window; two sets of the dopant bottles are respectively provided in the dual-position dopant barrel.

[0014] Optionally, the dual-position dopant cartridge is connected to the carrier gas and dopant gas of the photoionization ion mobility spectrometer respectively, and the flow rates of the two gases are different.

[0015] Optionally, the carrier gas flow rate is 200 ml / min to 400 ml / min.

[0016] Optionally, the air flow rate of the dopant gas is 50 ml / min to 200 ml / min.

[0017] Optionally, the dual dopant cartridge includes a first dopant cartridge and a second dopant cartridge; when the acetone or butanone in the first dopant cartridge is used up, the internal residual substances in the first dopant cartridge are thermally purged by a clean gas source, and the purging gas enters the photoionization ion mobility spectrometer detector; the acetone or butanone in the second dopant cartridge enters the photoionization ion mobility spectrometer detector through a normal path, and the obtained detection impurity signal is used to identify the acetone or butanone content.

[0018] Optionally, the photoionization ion mobility spectrometer is a unidirectional airflow, the gas flow rate of the drift gas is 500ml / min~800ml / min, the temperature of the migration tube is 100℃~140℃, the thermal desorption temperature is 120℃~180℃, the dopant temperature is 30~40℃, and the high voltage is 6000V~10000V.

[0019] Optionally, any concentration of acetone or butanone vapor can be released from the dopant bottle.

[0020] The implementation of the present invention will have the following beneficial effects:

[0021] The present invention provides a method for monitoring dopants using ion mobility spectrometry, utilizing a photoionization ion mobility spectrometer to detect impurity signals in acetone or butanone dopants. The analyzer is equipped with a dual-position dopant cartridge containing two sets of dopant vials capable of releasing any concentration of acetone or butanone. This method monitors acetone or butanone dopant usage in real time, effectively warning of impurity depletion and prompting prompt replacement, thereby preventing impurities from contaminating the ion mobility tube detector through photoionization. When impurity detection signals appear in acetone or butanone, the system automatically monitors and issues warnings in real time, prompting prompt replacement of the dopant as soon as possible. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is the background signal (air reagent ion peak) of the photoionization ion mobility spectrometer in Example 1 of the present invention.

[0023] Figure 2 This is the impurity detection signal of the dopant acetone in Example 2 of the present invention. DETAILED DESCRIPTION

[0024] The present invention will be further described below with reference to specific examples, but the present invention is not limited thereto in any way.

[0025] The invention discloses a detection method for monitoring dopants by ion mobility spectrometry. The method adopts ion mobility spectrometry technology, uses acetone or butanone as a dopant, and utilizes a photoionization ion mobility spectrometer to detect impurity signal peaks in the dopant acetone or butanone. The photoionization ion mobility spectrometer comprises a dopant cylinder, wherein a dopant bottle is provided in the dopant cylinder, and the dopant bottle is used to release acetone or butanone vapor. The acetone or butanone can be used as a carrier gas and a dopant gas to provide dopant molecules for the ion mobility spectrometer, which serve as photoionization product reagent ions.

[0026] In one embodiment, the dopant composition is determined based on the migration time, and the dopant content is determined based on the signal intensity.

[0027] In a specific embodiment, the photoionization ion mobility spectrometer includes a dual-position dopant barrel without a visual window; two sets of dopant bottles are respectively provided in the dual-position dopant barrel.

[0028] In a specific embodiment, the dual-position dopant cartridge is connected to the carrier gas and dopant gas of the photoionization ion mobility spectrometer respectively, and the two gas flows have different flow rates.

[0029] In one embodiment, the flow rate of the carrier gas is 300 ml / min.

[0030] In one embodiment, the flow rate of the dopant gas is 100 ml / min.

[0031] In a specific embodiment, the dual dopant cartridge includes a first dopant cartridge and a second dopant cartridge; when the acetone or butanone in the first dopant cartridge is used up, the internal residual material in the first dopant cartridge is thermally purged by a clean gas source, and the purging gas enters the photoionization ion mobility spectrometer detector; the acetone or butanone in the second dopant cartridge enters the photoionization ion mobility spectrometer detector through a normal path, and the obtained detection impurity signal is used to identify the acetone or butanone content.

[0032] In a specific embodiment, the photoionization ion mobility spectrometer has a unidirectional airflow, a gas flow rate of 600 ml / min for the drift gas, a temperature of the migration tube of 120° C., a thermal desorption temperature of 150° C., a dopant temperature of 35° C., a high voltage of 9000 V, and an ion gate pulse width of 50.

[0033] In one embodiment, any concentration of acetone or butanone vapor can be released from the dopant bottle.

[0034] The following are specific embodiments

[0035] Example 1

[0036] The method for monitoring dopant detection by ion mobility spectrometry of this embodiment employs ion mobility spectrometry technology, uses acetone as a dopant, and utilizes a photoionization ion mobility spectrometer to detect impurity signal peaks in the dopant acetone. The photoionization ion mobility spectrometer includes a dopant cartridge, which is provided with a dopant bottle for releasing acetone vapor. Acetone can be used as a carrier gas and dopant gas to provide dopant molecules to the ion mobility spectrometer, serving as photoionization product reagent ions.

[0037] The photoionization ion mobility spectrometer includes a dual-position dopant cartridge without a viewing window. Two sets of dopant bottles are housed within the dual-position dopant cartridge. The dual-position dopant cartridges are connected to the photoionization ion mobility spectrometer's carrier gas and dopant gas, respectively, with different flow rates. The dual dopant cartridges consist of a first dopant cartridge and a second dopant cartridge.

[0038] The photoionization ion mobility spectrometer had a unidirectional gas flow, acetone as Dopant, float gas 600 ml / min, Dopant gas 100 ml / min, carrier gas 300 ml / min, migration tube temperature 120 °C, thermal desorption temperature 150 °C, dopant temperature 35 °C, and high voltage 9000 V.

[0039] The background signal of the ion mobility spectrometer (air reagent ion peak) is as follows Figure 1 The strongest peak of acetone signal is located at 3.44ms.

[0040] Example 2

[0041] The method for monitoring dopant detection by ion mobility spectrometry of this embodiment employs ion mobility spectrometry technology, uses acetone as a dopant, and utilizes a photoionization ion mobility spectrometer to detect impurity signal peaks in the dopant acetone. The photoionization ion mobility spectrometer includes a dopant cartridge, which is provided with a dopant bottle for releasing acetone vapor. Acetone can be used as a carrier gas and dopant gas to provide dopant molecules to the ion mobility spectrometer, serving as photoionization product reagent ions.

[0042] The photoionization ion mobility spectrometer includes a dual-position dopant cartridge without a viewing window. Two sets of dopant bottles are housed within the dual-position dopant cartridge. The dual-position dopant cartridges are connected to the photoionization ion mobility spectrometer's carrier gas and dopant gas, respectively, with different flow rates. The dual dopant cartridges consist of a first dopant cartridge and a second dopant cartridge.

[0043] When the acetone in the first dopant tube is used up, the residual substances inside the first dopant tube are thermally purged by a clean gas source, and the purging gas enters the photoionization ion mobility spectrometer detector; the acetone in the second dopant tube enters the photoionization ion mobility spectrometer detector through a normal path, and the obtained detection impurity signal is used to identify the acetone content.

[0044] The instrument has a unidirectional airflow, acetone as Dopant, float gas 600ml / min, Dopant gas 100ml / min, carrier gas 300ml / min, migration tube temperature 120℃, thermal desorption temperature 150℃, dopant temperature 35℃, and high voltage 9000V.

[0045] The peak signal of air reagent ion is as follows Figure 1 As shown, the impurity detection signal of 1-way dopant dopant is as follows Figure 2 As shown in Figure 2, the strongest peak of the acetone signal is located at 3.44ms. A characteristic component signal of acetone appears at 4.82ms, 383mV.

[0046] By comparison Figure 1 and Figure 2 From the spectrum, we can see that impurity detection signals appeared in acetone. Figure 2 The characteristic acetone component signal peak at 4.82ms is of great significance. When the signal intensity of this peak exceeds 30mV, the system automatically monitors it in real time through software and issues an effective warning, indicating that the acetone dopant is about to be depleted and that new acetone needs to be replaced as soon as possible. Simultaneously, after this characteristic peak appears, the overall acetone signal gradually weakens until the acetone dopant signal disappears completely, while the impurity signal continues to strengthen and reach its peak.

[0047] The above-described embodiments merely represent several implementation methods of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A method for monitoring dopants by ion mobility spectrometry, characterized in that: Ion mobility spectrometry technology is used, acetone or butanone is used as a dopant, and the impurity signal peak in the dopant acetone or butanone is detected by photoionization ion mobility spectrometer; The photoionization ion mobility spectrometer includes a dopant barrel, wherein a dopant bottle is provided in the dopant barrel, and the dopant bottle is used to release acetone or butanone vapor; Acetone or butanone can be used as carrier gas and dopant gas to provide dopant molecules to the ion mobility spectrometer as photoionization product reagent ions.

2. The method for monitoring dopants by ion mobility spectrometry according to claim 1, characterized in that: The dopant composition is determined based on the migration time, and the dopant content is determined based on the signal intensity.

3. The method for monitoring dopants by ion mobility spectrometry according to claim 1, wherein: The photoionization ion mobility spectrometer includes a dual-position dopant cartridge and has no visual window; Two sets of dopant bottles are respectively provided in the dual-position dopant cylinder.

4. The method for monitoring dopants by ion mobility spectrometry according to claim 3, characterized in that: The dual-position dopant cylinder is connected to the carrier gas and dopant gas of the photoionization ion mobility spectrometer respectively, and the flow rates of the two gases are different.

5. The method for monitoring dopants by ion mobility spectrometry according to claim 4, characterized in that: The carrier gas flow rate is 200ml / min to 400ml / min; The flow rate of the dopant gas is 50 ml / min to 200 ml / min.

6. The method for monitoring dopants by ion mobility spectrometry according to claim 4, characterized in that: The dual dopant cartridge includes a first dopant cartridge and a second dopant cartridge; When the acetone or butanone in the first dopant tube is used up, the residual substances in the first dopant tube are thermally purged by a clean gas source, and the purging gas enters the detector of the photoionization ion mobility spectrometer; The acetone or butanone in the second dopant cylinder enters the photoionization ion mobility spectrometer detector through a normal path, and the obtained detection impurity signal is used to identify the acetone or butanone content.

7. The method for monitoring dopants by ion mobility spectrometry according to claim 6, characterized in that: The photoionization ion mobility spectrometer has a unidirectional airflow, a drift gas flow rate of 500ml / min to 800ml / min, a migration tube temperature of 100°C to 140°C, a thermal desorption temperature of 120°C to 180°C, a dopant temperature of 30°C to 40°C, and a high voltage of 6000V to 10000V.

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