Method for detecting helicobacter pylori by adopting ion mobility spectrometry

Abstract

The invention relates to a method for detecting helicobacter pylori by adopting ion mobility spectrometry, which comprises the following steps: detecting stomach helicobacter pylori by monitoring the nasal exhaled ammonia concentration change rate (CCR) of a physical examinee before and after taking non-radioactive urea, and comparing the result with the 14C / 13C urea exhaling experiment result of the physical examinee; according to the method, the concentration of exhaled gas ammonia before and after a physical examination person takes non-radioactive urea is detected by adopting a photoionization ion mobility spectrometry technology, the change rate CCR of the exhaled gas ammonia concentration at different moments is calculated, when the CCR is larger than or equal to 20.2%, the detected person is prompted to be positive of helicobacter pylori, and when the CCR is smaller than 20.2%, the detected person is prompted to be negative of helicobacter pylori. The method for detecting the helicobacter pylori is non-invasive, rapid, sensitive and simple, and is very suitable for clinically detecting the helicobacter pylori and reducing the incidence rate of gastric cancer.

Description

Technical Field

[0001] This invention belongs to the field of analytical chemistry instruments, and specifically relates to a method for detecting Helicobacter pylori using ion mobility spectrometry. Background Technology

[0002] Helicobacter pylori is a major pathogenic factor for chronic gastritis, peptic ulcers, and gastric cancer. Currently, the gold standard for clinical detection is invasive endoscopic gastric mucosal biopsy, which is difficult for patients to accept and is not widely used for infection screening and early prevention of digestive tract diseases. A non-invasive detection method is the urea breath test (UBT), which involves taking a urea-containing... 13 C or 14 C-labeled urea is decomposed into CO2 and NH3 by urease secreted by Helicobacter pylori. The CO2 and NH3 in exhaled breath can be detected by spectroscopy, mass spectrometry, or scintillation. 13 CO2 or 14 CO2 can be used to determine whether someone is infected with Helicobacter pylori. However, isotope-labeled drugs are expensive and radioactive. 13 C or 14 C-urea is not suitable for pregnant women or children.

[0003] This invention provides a method for rapidly and quantitatively detecting the concentration of ammonia in exhaled nasal air using ion mobility spectrometry. It measures the difference in terminal NH3 concentration in exhaled nasal air and the rate of change (CCR) of ammonia concentration in exhaled nasal air before and after a subject takes a non-radioactive urea capsule. This method has a sensitivity of up to 84.2% and a specificity of up to 92.2% in detecting Helicobacter pylori.

[0004] The method for detecting Helicobacter pylori using ion mobility spectrometry provided by this invention has the advantages of being non-invasive, portable, low-cost, and easy to use for general screening of Helicobacter pylori. It has important clinical significance for the early detection of Helicobacter pylori and reducing the risk of gastric cancer. Summary of the Invention

[0005] To address the shortcomings of existing technologies in detecting Helicobacter pylori, the present invention aims to provide a method for detecting Helicobacter pylori using ion mobility spectrometry. This method involves the subject orally ingesting a non-radioactive urea capsule, and then using ion mobility spectrometry to detect the change rate of ammonia concentration in the subject's nasal exhaled air before and after ingestion of the non-radioactive urea capsule. This invention has the advantages of being non-invasive, non-radioactive, widely applicable, rapid, sensitive, and simple, making it very suitable for clinical detection of Helicobacter pylori.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A method for detecting Helicobacter pylori using ion mobility spectrometry, wherein the method uses ion mobility spectrometry to detect the concentration of exhaled ammonia (C1) before the subject takes a non-radioactive urea capsule orally and the concentration of exhaled ammonia (C2) at any time 15-50 mins (preferably 15-30 mins) after taking the non-radioactive urea capsule orally. The change rate (CCR) of the exhaled ammonia concentration before and after the subject takes the non-radioactive urea capsule orally is calculated, and CCR = (C2-C1) / C1*100%. When CCR ≥ 20.2%, the subject is considered positive for Helicobacter pylori, and when CCR < 20.2%, the subject is considered negative for Helicobacter pylori.

[0008] The specific detection process of the method is as follows: First, the concentration of ammonia in the breath of the subject before oral administration of non-radioactive urea capsules (C1) is detected using ion mobility spectrometry. Then, the subject takes an appropriate dose of non-radioactive urea capsules orally and sits quietly for 15-50 minutes. The concentration of ammonia in the breath of the subject after oral administration of non-radioactive urea capsules (C2) is detected using ion mobility spectrometry. Finally, the rate of change of the concentration of ammonia in the breath of the subject before and after oral administration of non-radioactive urea capsules (CCR) is calculated. CCR = (C2-C1) / C1*100%. When CCR ≥ 20.2%, it indicates that the subject is positive for Helicobacter pylori. When CCR < 20.2%, it indicates that the subject is negative for Helicobacter pylori.

[0009] The detection method described is not applicable to the diagnosis and treatment of diseases.

[0010] The ion mobility spectrum is the photoionization ion mobility spectrum of the acetone modifier, and the photoionization source is a radio frequency ultraviolet (VUV) lamp.

[0011] The non-radioactive urea capsules are ordinary edible urea containing urea, and the amount of non-radioactive urea capsules orally administered to the subjects is 75mg-300mg (preferably 100-200mg).

[0012] Furthermore, the concentration of exhaled ammonia was detected by real-time sampling and detection of exhaled ammonia from the nasal cavity.

[0013] Furthermore, the real-time sampling and detection process of ammonia in nasal exhalation is as follows: the subject exhales into the ion mobility spectrometer by facing the sampling nozzle of the nasal cavity, and the exhaled air sample is drawn into the ion mobility spectrometer for real-time detection by the air pump.

[0014] The conditions for ion mobility spectrometry sampling and detection during the detection of exhaled ammonia concentration are as follows:

[0015] The electric field strength of the migration tube is 200-400 V / cm, and the temperature is 80-150℃. The flow rates of the acetone carrier gas, bleaching gas, and pump are controlled by a mass flow controller, set to 50-150 mL / min, 300-600 mL / min, and 350-750 mL / min, respectively. The pump flow rate is greater than the sum of the carrier gas and bleaching gas flow rates; therefore, the negative pressure created in the migration tube allows the exhaled gas sample to automatically enter the ionization region from the inlet. The concentration of acetone reagent molecules introduced from the bleaching gas is 150-250 ppm.

[0016] The sampling flow rate at the ion migration tube sample inlet is 50-250 mL / min, the online dilution compensation gas flow rate is 50-150 mL / min, and the online dilution purge gas flow rate is 1000-2500 mL / min. The ion gate opening time is 30-150 μs, the ion gate applied voltage is 200-400 V, the time for a single migration spectrum is 8-10 ms, the ion migration spectrum is obtained by averaging 10 original spectra, and the single detection time is approximately 80-100 ms.

[0017] The acetone carrier gas, bleaching gas, online dilution compensation gas, and online dilution purge gas are all clean air that has been purified sequentially by silica gel, activated carbon, and 13X molecular sieve.

[0018] The ammonia concentrations C1 and C2 in the exhaled breath before and after oral administration of non-radioactive urea capsules were obtained using a quantitative standard curve equation for nasal exhaled ammonia. The equation for the quantitative standard curve equation for nasal exhaled ammonia was: Y = 6.17 * 10⁻⁶. -3 +7.81*10 -4 X, where Y represents the quantitative factor of exhaled ammonia, X represents the concentration of exhaled ammonia, and R 2 This indicates the goodness of fit of the quantitative curve.

[0019] The quantitative factor for exhaled ammonia is the ratio of the signal intensity of exhaled ammonia in the ion mobility spectrum to the total ion signal intensity in the ion mobility spectrum.

[0020] Compared with existing technologies, the advantages of this invention are as follows: It develops photoionization ion mobility spectrometry (PHS) for the detection of ammonia in nasal exhaled breath, offering high sensitivity, good selectivity, and strong resistance to matrix interference. Furthermore, it is the first time that nasal exhaled breath ammonia measurement has been used in Helicobacter pylori detection. By detecting the rate of change (CCR) of nasal exhaled NH3 concentration before and after taking ordinary urea capsules, it can correct for differences in endogenous NH3 concentration related to basal metabolic rate (BMR) influenced by factors such as age, sex, height, and weight, further improving the accuracy and reliability of NH3-UBT detection of Helicobacter pylori. As a novel method for Helicobacter pylori detection, PHS uses unlabeled ordinary urea, significantly reducing detection costs and avoiding radioactive interference. It has significant clinical application value for Helicobacter pylori detection and is beneficial for the early diagnosis and timely treatment of gastric cancer. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the ion mobility spectrum for detecting ammonia in exhaled nasal gas. In the diagram, 1 is the sampling port, 2 is the glass sampling tube, 3 is the online dilution purge gas, 4 is the sample inlet, 5 is the radio frequency ultraviolet lamp ionization source, 6 is the ion molecular reaction region, 7 is the ion gate, 8 is the migration region, 9 is the Faraday disk receiver, 10 is the acetone-doped drift gas inlet, 11 is the outlet, and 12 is the online dilution compensation gas inlet. Figure 2 This is a standard quantitative curve for ammonia exhaled through the nasal cavity.

[0022] Figure 3 The images show the ammonia signal spectrum in exhaled nasal gas and a comparison of ammonia concentrations in four consecutive exhaled nasal gases. (a) shows the ammonia concentration inhaled by an Hp-negative individual. 14 Before C urea reagent (C1 above) and intake 14 (c) The intensity spectrum of ammonia signal in exhaled nasal gas after 26 minutes with urea reagent (C2 below), (b) is the ammonia signal intensity spectrum ingested by the Hp-negative individual. 14 C urea reagent before and after intake 14 Comparison of ammonia concentrations in four consecutive nasal exhalations of urea reagent over 26 minutes (c) shows the concentration inhaled by an Hp-positive individual. 14 Before C urea reagent (C1 above) and intake 14 The intensity spectrum of ammonia signal in exhaled nasal gas after 30 minutes with urea reagent (C2 below), (d) is the ammonia signal intensity spectrum of the Hp-positive individual. 14 C urea reagent before and after intake 14 Comparison of ammonia concentration in four consecutive nasal exhalations after 30 minutes using C-urea reagent.

[0023] Figure 4 Hp-negative and Hp-positive groups took 14Correlation analysis of the difference in nasal ammonia concentration (C2-C1) after C-urea and detection time, where (a) is the correlation graph of C2-C1 and C2 collection time in the Hp-negative group, and (b) is the correlation graph of C2-C1 and C2 collection time in the Hp-positive group.

[0024] Figure 5 (a) administering medication to the subject 14 CCR and the rate of change of nasal expiratory ammonia concentration after C urea 14 Correlation analysis of C-UBT test results, (b) is 14 Comparison of the rate of change in ammonia concentration in exhaled nasal air between the Hp-positive and Hp-negative groups detected by C-UBT.

[0025] Figure 6 The rate of change of exhaled ammonia concentration (CCR) and the receiver operating curve (ROC) model for Helicobacter pylori positive and negative groups. Detailed Implementation

[0026] The specific embodiments of the present invention will be described in more detail below with reference to the accompanying drawings and examples, so as to better understand the solution of the present invention and the advantages of each aspect.

[0027] like Figure 1 As shown, the ion mobility spectrometry used in this invention includes an ion mobility spectrometry sampling port, a sample gas inlet, a radio frequency ultraviolet lamp ionization source, an acetone-doped drift gas inlet, an ion molecular reaction region, an ion gate, and a migration region.

[0028] A radio frequency ultraviolet lamp ionization source and a Faraday disk receiver are respectively set at the left and right ends of the ion mobility spectrum. An ion gate is set between the radio frequency ultraviolet lamp ionization source and the Faraday disk receiver. The region between the radio frequency ultraviolet lamp ionization source and the ion gate is the ion molecular reaction region. The region between the ion gate and the Faraday disk receiver is the migration region. The Faraday disk receiver is connected to the ion mobility spectrum data acquisition device.

[0029] A sample inlet is provided on the upper wall of the ion mobility spectrum ion molecular reaction region near the ion gate, and an outlet is provided on the upper wall of the ion mobility spectrum ion molecular reaction region near the radio frequency ultraviolet lamp ionization source. The outlet is connected to one end of the outlet pipeline, and the other end of the outlet pipeline is connected to a vacuum pump for venting (connected to the atmosphere). The outlet, the sample inlet, and an acetone-doped drift gas inlet on the Faraday disk receiver electrode on the outer wall of the ion mobility spectrum migration region together form the external interface of the gas circulation system of the ion mobility spectrum. The acetone-doped drift gas enters the ion mobility spectrum migration region through the acetone-doped drift gas inlet.

[0030] One end of a glass sampling tube is a sampling port, through which exhaled air from the nasal cavity is sampled and enters the glass sampling tube. The other end of the glass sampling tube is connected to the sample inlet of the ion mobility spectrometry (IMS) ion molecular reaction zone via a tubing. An online dilution compensation gas inlet is installed on the tubing connecting the glass sampling tube to the sample inlet of the IMS ion molecular reaction zone. During sampling, the online dilution compensation gas enters the connecting tubing through the online dilution compensation gas inlet to dilute the sample gas. A purge gas inlet is installed at the end of the glass sampling tube near the sampling port. During sampling, the online dilution purge gas enters the glass sampling tube through the purge gas inlet to dilute the sampled exhaled air from the nasal cavity online.

[0031] The migration tube consists of dozens of stacked stainless steel and polytetrafluoroethylene rings. The entire cavity of the migration tube is divided into an ionization region and an ion drift region by a Tyndall-Powell ion gate, with lengths of 25 mm and 77 mm, respectively. The photoionization source uses a commercially available radio frequency ultraviolet (VUV) lamp with a photon energy of 10.6 eV.

[0032] To verify the reliability and accuracy of the ion mobility spectrometry method for detecting Helicobacter pylori (Hp) of this invention, the results obtained by the testers using the method of this invention were compared with those obtained using... 14 The results obtained from C-UBT detection were compared and correlation analyzed.

[0033] 1. Randomly select hospitals to conduct 14 The C-UBT test was conducted on 318 subjects aged 24-89 years, who were used for comparison and correlation analysis of the two test results. They fasted for at least 8 hours and did not smoke 2 hours before and during the test.

[0034] 2. Testing Process: First, exhaled breath samples from each subject are collected using a gas collection card (once the color bar on the gas collection card turns orange, exhalation is stopped and the sample is used for hospital spectral analysis). 14 CO2 was detected, and ion mobility spectrometry was used to detect the oral ions of all subjects. 14 The concentration of ammonia in the prenasal exhaled air was C1, which was then administered orally by the subject to a hospital-provided urea reagent. 14 C-urea reagent (dosage 75mg), sit quietly for 15-50 minutes and collect exhaled breath samples using a gas collecting card for use. 14 CO2 was detected, and ion mobility spectrometry was used to detect the oral ions of all subjects. 14 The concentration of ammonia C2 in the nasal exhaled air after 15-50 minutes using urea reagent was calculated, and the amount of ammonia C2 in the subject's oral urea solution was determined. 14 The change rate (CCR) of NH3 concentration at the end of exhaled nasal air before and after urea reagent preparation is shown in the following formula:

[0035] CCR% = (C2-C1) / C1*100%,

[0036] The ammonia concentrations C1 and C2 in the exhaled breath before and after oral administration of non-radioactive urea capsules were obtained using a quantitative standard curve equation for nasal exhaled ammonia. The equation for the quantitative standard curve equation for nasal exhaled ammonia was: Y = 6.17 * 10⁻⁶. -3 +7.81*10 -4 X, where Y represents the quantitative factor of exhaled ammonia, and X represents the concentration of exhaled ammonia.

[0037] Ten sets of standard ammonia samples were selected within the concentration range of 10-200 ppb at 100% RH humidity. The concentrations were 16 ppbv, 20 ppbv, 30 ppbv, 50 ppbv, 80 ppbv, 100 ppbv, 150 ppbv, 200 ppbv, 250 ppbv, and 300 ppbv. Five parallel samples were taken from each set. Ion mobility spectrometry was used to detect the ammonia standard gases of the above ten sets at different concentrations. The ion mobility spectra and quantification factors of ammonia at different concentrations were obtained, which were 0.02, 0.022, 0.029, 0.042, 0.069, 0.086, 0.123, 0.163, 0.203, and 0.238, respectively. The linear equation Y = 6.17 * 10⁻⁶ was obtained by fitting a standard curve for the quantification of ammonia in nasal exhaled gas. -3 +7.81*10 -4 X, such as Figure 2 As shown.

[0038] 3. Comparison 14 The nasal exhaled ammonia signal spectra of two subjects diagnosed with Hp positivity and Hp negativity by C-UBT testing. (See attached image.) Figure 3 As shown, the oral administration of medication was compared between one Hp-positive patient and one Hp-negative patient. 14 Ammonia signal spectrum of exhaled breath before and after C-urea reagent. Figure 3 (a) and Figure 3 (b) respectively via 14 A case of Hp-negative patient diagnosed with C-UBT (dpm=0) ingested 14 Before C urea reagent (C1 above) and intake 14 The intensity spectrum of exhaled ammonia signal in the nasal cavity at 26 minutes (C2 below) using urea reagent C, and the comparison of ammonia concentration in four consecutive exhaled nasal vomitings, showed little difference in the intensity of exhaled ammonia signal in the nasal cavity before and after urea ingestion in this subject (e.g., Figure 3 (b) shows four consecutive tests. 14 There was no significant difference in the concentration of ammonia in the exhaled nasal cavity before and after the intake of C urea reagent [56.1±1.1ppb (average of the 5 times before intake) vs 58.1±4.1ppb (average of the 5 times after intake), P=0.384]. Figure 3 (c) and Figure 3 (d) are respectively via 14Intake of a C-UBT-diagnosed Hp-positive individual (dpm=169) 14 Before C urea reagent (C1 above) and intake 14 The nasal ammonia signal intensity spectrum of the C urea reagent after 30 minutes (C2 below) shows the ammonia signal intensity in the nasal cavity of the positive subject at the time of ingestion. 14 C urea reagent significantly increased, and its intake was calculated. 14 The concentration of ammonia in exhaled nasal gas after urea reagent treatment (123.6±7.6 ppb) was significantly higher than that in ingested ammonia. 14 Nasal ammonia concentration level before C-urea reagent (91.7±3.3ppb, P=0.003).

[0039] 4. The subject's CCR value was used to predict whether the subject was Hp-positive or negative, and this was compared with the hospital's... 14 The C-UBT test results were compared, and the results are shown in Table 1.

[0040] Table 1 Subjects took 14 The CCR prediction results of the change rate of nasal expiratory ammonia concentration before and after C-urea administration and 14 C-UBT detection results for Helicobacter pylori classification.

[0041]

[0042] Hospital 14 C-UBT diagnostic criteria: >100 dpm / mmol 14 CO2 was detected as Hp infection (positive), 0–99 dpm / mmol 14 CO2 is considered a negative result for those not infected with Hp. 14 C-UBT test results showed that among the 318 subjects tested, 101 were Hp positive and 217 were Hp negative. The CCR values ​​of the subjects were calculated, with 102 cases having a CCR ≥ 20.2% and 216 cases having a CCR < 20.2%. 14 The C-UBT test results were the standard. The positive predictive value (PPV) of CCR for Hp was 83.3% (85 / 102 cases), the negative predictive value (NPV) was 92.6% (200 / 216 cases), and the overall predictive accuracy was 89.6% (285 / 318 cases).

[0043] 5. With 14 The C-UBT test result was the standard; both the Hp-negative and Hp-positive groups took [the medication / treatment]. 14 Correlation analysis was performed on the difference in nasal ammonia concentration (C2-C1) after C-urea administration and the detection time. The correlation analysis was expressed using the Pearson correlation coefficient (r).

[0044] Subjects taking 14Before taking C-urea, the concentration of NH3 at the end of the nasal exhalation was measured to be C1, and then the following medication was taken. 14 Using C-urea reagent, the concentration of ammonia exhaled through the nasal cavity (C2) of the subject was collected at minute t (t = 15-50) after sitting still. Ion mobility spectrometry was then used to calculate the concentration of ammonia (C2) in the nasal cavity at minute t. 14 The difference in NH3 concentration at the end of exhaled air in the nasal cavity before and after the C urea reagent (C2-C1).

[0045] Plot a graph with the subject's C2 collection time on the x-axis and the NH3 concentration difference at the end of the subject's nasal exhalation (C2-C1) on the y-axis, as shown below. Figure 3 As shown, where, Figure 4 (a) is a correlation plot of the collection times of C2-C1 and C2 in the Hp-negative group. The Pearson correlation coefficient r = -0.02, indicating no correlation between the two. Figure 4 (b) shows the correlation between the C2-C1 and C2 collection times in the Hp-positive group. The Pearson correlation coefficient r = 0.19, indicating a weak correlation between the two. Therefore, there is a weak correlation between the terminal NH3 concentration difference in nasal exhalation (C2-C1) and the C2 collection time. The C2 collection time can be used as a reference for the administration of medication. 14 Any time between 15 and 50 minutes after applying C-urea reagent.

[0046] 6. Administer the medication to the subjects. 14 CCR and the rate of change of nasal expiratory ammonia concentration after C urea 14 C-UBT detection value 14 Correlation analysis was performed on CO2 (dpm), and the correlation coefficient (r) was used to represent the correlation.

[0047] Subjects 14 C-UBT detection value 14 A scatter plot was created with CO2 (dpm) on the x-axis and the rate of change in NH3 concentration at the end of the subject's nasal exhalation (CCR) (%) on the y-axis. Figure 5 As shown in (a). 14 C-UBT detection value 14 CO2 (dpm) and the rate of change of NH3 concentration at the end of nasal exhalation (CCR) (%) showed a significant positive correlation (r = 0.62, P < 0.001).

[0048] Subjects 14 The C-UBT testing standard divides subjects into Hp-positive and Hp-negative groups, and determines the dosage of Hp medication by the subjects. 14 A scatter plot was plotted on the ordinate of the change in ammonia concentration in exhaled nasal air before and after the application of urea reagent C, as shown below. Figure 5 As shown in (b), the rate of change in exhaled ammonia concentration in the Hp-positive group (47.5±39.3%) was significantly higher than that in the negative group (1.6±17.9%, P<0.001).

[0049] 7. With 14 C-UBT, as the gold standard for diagnosing *Helicobacter pylori* (Hp) infection, assesses the diagnostic significance of the rate of change in exhaled ammonia concentration (C2-C1) / C1*100% for Hp infection. The results are as follows: Figure 6 As shown. The area under the ROC curve was 0.919 (95% confidence interval, 0.882–0.956). Based on the Youden index = max(sensitivity + specificity - 1), a 20.2% change in nasal exhaled ammonia concentration was used as the cutoff point for predicting *H. pylori* infection, with a sensitivity of 84.2% and a specificity of 92.2%.

[0050] Example 1

[0051] A 45-year-old male with a BMI of 26.23 was randomly selected for a physical examination. He had fasted for at least 8 hours and had not smoked for 2 hours prior to the test. Ion mobility spectrometry (IMS) was used to measure the ammonia concentration (C1) in his exhaled breath before ingesting a non-radioactive urea capsule, which was 84.59 ppb. Then, the examinee ingested a 75 mg non-radioactive urea capsule and sat quietly for 32 minutes. IMS was used again to measure the ammonia concentration (C2) 32 minutes after ingestion, which was 132.78 ppb. The change rate (CCR) of the ammonia concentration in exhaled breath before and after ingestion of the non-radioactive urea capsule was calculated using the formula CCR = (C2 - C1) / C1 * 100%, which was 56.96%, indicating that the examinee was positive for Helicobacter pylori.

[0052] During the detection process, the experimental conditions used for ion mobility spectrometry were as follows: electric field strength of the migration tube was 350 V / cm, temperature of the migration tube was 130℃, acetone carrier gas flow rate was 100 mL / min, bleaching gas flow rate was 500 mL / min, and the gas pump flow rate was 800 mL / min. The concentration of acetone reagent molecules introduced from the bleaching gas was 216 ppm.

[0053] The sampling flow rate at the ion migration tube sample inlet was 200 mL / min, the online dilution compensation gas flow rate was 150 mL / min, and the online dilution purge gas flow rate was 2000 mL / min. The ion gate opening time was 50 μs, the ion gate applied voltage was 350 V, the time for a single migration spectrum was 8 ms, the ion migration spectrum was obtained by averaging 10 original spectra, and the single detection time was approximately 80 ms.

[0054] Example 2

[0055] A 28-year-old female with a BMI of 16.26 was randomly selected for a physical examination. She had fasted for at least 8 hours and had not smoked for 2 hours prior to the test. First, ion mobility spectrometry (IMS) was used to determine the ammonia concentration (C1) in her exhaled breath before ingesting a non-radioactive urea capsule, which was 43.73 ppb. Then, she ingested the non-radioactive urea capsule (75 mg) and sat quietly for 19 minutes. IMS was used again to determine the ammonia concentration (C2) in her exhaled breath 19 minutes after ingestion, which was 46.75 ppb. The change rate (CCR) of the ammonia concentration in her exhaled breath before and after ingestion of the non-radioactive urea capsule was calculated using the formula CCR = (C2 - C1) / C1 * 100%, which was 6.90%, indicating that the patient was Helicobacter pylori negative. The experimental conditions used for ion mobility spectrometry during the test were the same as in Example 1.

[0056] Example 3

[0057] A 50-year-old female with a BMI of 21.1 was randomly selected for a physical examination. She had fasted for at least 8 hours and had not smoked for 2 hours prior to the test. First, ion mobility spectrometry (IMS) was used to determine the concentration of ammonia in her exhaled breath (C1) before she took a non-radioactive urea capsule (75 mg). She sat quietly for 18 minutes. IMS was then used again to determine the concentration of ammonia in her exhaled breath (C2) 18 minutes after taking the capsule. The concentration was 61.74 ppb. The change rate of ammonia concentration in exhaled breath before and after taking the non-radioactive urea capsule (CCR) was calculated using the formula CCR = (C2 - C1) / C1 * 100%. The CCR was 24.31%, indicating that the examinee was positive for Helicobacter pylori. The experimental conditions used for ion mobility spectrometry during the test were the same as in Example 1.

Claims

1. A method for detecting Helicobacter pylori using ion mobility spectrometry, characterized in that, Ion mobility spectrometry was used to detect the concentration of exhaled ammonia (C1) before oral administration of non-radioactive urea capsules and the concentration of exhaled ammonia (C2) at any time 15-50 mins (preferably 15-30 mins) after oral administration of non-radioactive urea capsules. The rate of change (CCR) of the exhaled ammonia concentration before and after oral administration of non-radioactive urea capsules was calculated. CCR = (C2-C1) / C1*100%. When CCR ≥ 20.2%, it indicates that the subject is positive for Helicobacter pylori. When CCR < 20.2%, it indicates that the subject is negative for Helicobacter pylori. The detection method described is not applicable to the diagnosis and treatment of diseases.

2. The method according to claim 1, characterized in that, The ion mobility spectrum is the photoionization ion mobility spectrum of the acetone modifier, and the photoionization source is a radio frequency ultraviolet (VUV) lamp.

3. The method according to claim 1, characterized in that, The non-radioactive urea capsules are ordinary edible urea containing urea. The amount of non-radioactive urea capsules orally administered to the test subject is 75mg-300mg (preferably 100-200mg).

4. The method according to claim 1, characterized in that, The concentration of exhaled ammonia was detected by real-time sampling of exhaled ammonia from the nasal cavity.

5. The method according to claim 4, characterized in that, The real-time sampling and detection process of ammonia in nasal exhalation is as follows: the subject exhales directly into the ion mobility spectrometer sampling port in the nasal cavity, and the exhaled air sample is drawn in by the air pump and enters the ion mobility spectrometer for real-time detection.

6. The method according to claim 1 or 4, characterized in that, During the detection of ammonia concentration in exhaled breath, the ion mobility spectrometry sampling conditions were as follows: the electric field strength of the migration tube was 200-400 V / cm, the temperature of the migration tube was 80-150℃, and the flow rates of acetone carrier gas, bleaching gas, and suction pump were set to 50-150 mL / min, 300-600 mL / min, and 350-750 mL / min, respectively; the concentration of acetone reagent molecules introduced from the bleaching gas was 120-250 ppm. The sampling flow rate at the ion migration tube sample inlet is 50-250 mL / min, the online dilution gas compensation flow rate is 50-150 mL / min, and the online dilution purge gas flow rate is 1000-2500 mL / min; the ion gate opening time is 30-150 μs, the ion gate applied voltage is 200-400 V, the time for a single migration spectrum is 8-10 ms, the ion migration spectrum is obtained by averaging 10 original spectra, and the single detection time is approximately 80-100 ms.

7. The method according to claim 1, characterized in that, The ammonia concentrations C1 and C2 in the exhaled breath before and after oral administration of non-radioactive urea capsules were obtained using a quantitative standard curve equation for nasal exhaled ammonia. The equation for the quantitative standard curve equation for nasal exhaled ammonia was: Y = 6.17 * 10⁻⁶. -3 +7.81*10 -4 X, where Y represents the quantitative factor of exhaled ammonia and X represents the concentration of exhaled ammonia.

8. The method according to claim 7, characterized in that, The quantitative factor for exhaled ammonia is the ratio of the signal intensity of exhaled ammonia in the ion mobility spectrum to the total ion signal intensity in the ion mobility spectrum.

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