1.Effect of biological amniotic membrane soaked in pirfenidone on scar formation after glaucoma filtration surgery in rabbit eyes
Shuai ZHANG ; Yihua YAO ; Yangjing ZHENG ; Ping WU ; Yihua ZHU
International Eye Science 2024;24(2):189-195
AIM: To investigate the application of biological amniotic membrane soaked in pirfenidone(PFD)and to evaluate its anti-scarring effect and toxic side effects on glaucoma model of rabbit eyes.METHODS: The right eyes of 72 healthy New Zealand white rabbits were randomly divided into 0.5%PFD+ biological amniotic membrane group, biological amniotic membrane group, mitomycin C(MMC)group and blank control group after the glaucoma model was established by anterior chamber injection of compound carbomer solution, and 18 rabbits in each group underwent trabeculectomy, in which the 0.5% PFD+ biological amniotic membrane group was placed with 0.5% PFD solution-soaked biological amniotic membrane under the scleral flap, and the biological amniotic membrane group was placed with normal saline-soaked rehydrated biological amniotic membrane under the scleral flap. In the MMC group, a cotton pad soaked in MMC was placed under the scleral flap for 3 min and immediately rinsed with normal saline, while the blank control group received no implant after the scleral flap was made. The intraocular pressure(IOP), filtration blebs, toxic side effects and complications were evaluated, and the histopathological changes in the filtration area were observed by hematoxylin-eosin(HE), Masson staining and immunohistochemical staining.RESULTS: The mean IOP at 14, 21 and 28 d after trabeculectomy were 0.5%PFD+ biological amniotic membrane group<MMC group<biological amniotic membrane group<blank control group(all P<0.05). At 28 d after trabeculectomy, 0.5%PFD+ biological amniotic membrane group had the best effect of anti-inflammatory hyperplasia and inhibition of collagen formation, the highest survival rate of filtration blebs, and the inflammatory reaction was mild.CONCLUSION: Biological amniotic membrane soaked in pirfenidone has more obvious anti-scarring effect on glaucoma model, with less toxic side effects and good safety.
2.Effects of dapagliflozin on ischemic ventricular arrhythmia in rats by regulating JAK2/STAT3 axis
Jing LING ; Yao WU ; Guo-Ping TIAN
The Chinese Journal of Clinical Pharmacology 2024;40(3):388-392
Objective To investigate the effect and mechanism of dapagliflozin(DAPA)on ischemic ventricular arrhythmia(VA)in rats by regulating the Janus kinase 2(JAK2)/signal transducer and activator of transcription 3(STAT3)axis.Methods The rats were randomly divided into sham operation group,model group,experimental-L,-M,-H groups and AG490 group.All groups except sham group were established model of ischemic VA by ligation of the left anterior descending coronary artery(LAD).After 48 h of modeling,the experimental-L,-M,-H groups were given 1,3,5 mg·kg-1 DAPA by gavage,respectively;the AG490 group were given 5 mg·kg-1 DAPA+5 mg·kg-1 AG490 by gavage,once a day for 30 days.The arrhythmia scores of rats were examined by electrocardiogram;the expression levels of phosphorylated JAK2(p-JAK2)/JAK2 and phosphorylated STAT3(p-STAT3)/STAT3 proteins in myocardial tissue were detected by Western blotting.Results The arrhythmia scores of the sham operation group,model group,experimental-L,-M,-H groups and AG490 group were(0.00±0.00),(4.36±0.52),(3.41±0.42),(2.84±0.33),(2.13±0.26)and(3.74±0.43)points;the relative expression levels of p-JAK2/JAK2 were 0.98±0.10,0.41±0.05,0.62±0.07,0.74±0.08,0.91±0.09 and 0.52±0.06;the relative expression levels of p-STAT3/STAT3 were 0.93±0.09,0.33±0.04,0.57±0.06,0.78±0.08,0.89±0.09 and 0.49±0.05,respectively.There were significant differences in the above indexes between the model group and the sham operation group,experimental-L,-M,-H groups(all P<0.05);compared with the experimental-H group,the difference of AG490 was statistically significant(all P<0.05).Conclusion DAPA may improve ischemic VA in rats by activating the JAK2/STAT3 signaling pathway and inhibiting inflammatory response and oxidative stress.
3.Relationship between Phenotypic Changes of Dendritic Cell Subsets and the Onset of Plateau Phase during Intermittent Interferon Therapy in Patients with CHB
Liu YANG ; Yu Shi WANG ; Ting Ting JIANG ; Wen DENG ; Min CHANG ; Ling Shu WU ; Hua Wei CAO ; Yao LU ; Ge SHEN ; Yu Ru LIU ; Jiao Yuan GAO ; Jiao Meng XU ; Ping Lei HU ; Lu ZHANG ; Yao XIE ; Hui Ming LI
Biomedical and Environmental Sciences 2024;37(3):303-314
Objective This study aimed to evaluate whether the onset of the plateau phase of slow hepatitis B surface antigen decline in patients with chronic hepatitis B treated with intermittent interferon therapy is related to the frequency of dendritic cell subsets and expression of the costimulatory molecules CD40,CD80,CD83,and CD86. Method This was a cross-sectional study in which patients were divided into a natural history group(namely NH group),a long-term oral nucleoside analogs treatment group(namely NA group),and a plateau-arriving group(namely P group).The percentage of plasmacytoid dendritic cell and myeloid dendritic cell subsets in peripheral blood lymphocytes and monocytes and the mean fluorescence intensity of their surface costimulatory molecules were detected using a flow cytometer. Results In total,143 patients were enrolled(NH group,n = 49;NA group,n = 47;P group,n = 47).The results demonstrated that CD141/CD1c double negative myeloid dendritic cell(DNmDC)/lymphocytes and monocytes(%)in P group(0.041[0.024,0.069])was significantly lower than that in NH group(0.270[0.135,0.407])and NA group(0.273[0.150,0.443]),and CD86 mean fluorescence intensity of DNmDCs in P group(1832.0[1484.0,2793.0])was significantly lower than that in NH group(4316.0[2958.0,5169.0])and NA group(3299.0[2534.0,4371.0]),Adjusted P all<0.001. Conclusion Reduced DNmDCs and impaired maturation may be associated with the onset of the plateau phase during intermittent interferon therapy in patients with chronic hepatitis B.
4.Association of Cytokines with Clinical Indicators in Patients with Drug-Induced Liver Injury
Hua Wei CAO ; Ting Ting JIANG ; Ge SHEN ; Wen DENG ; Yu Shi WANG ; Yu Zi ZHANG ; Xin Xin LI ; Yao LU ; Lu ZHANG ; Yu Ru LIU ; Min CHANG ; Ling Shu WU ; Jiao Yuan GAO ; Xiao Hong HAO ; Xue Xiao CHEN ; Ping Lei HU ; Jiao Meng XU ; Wei YI ; Yao XIE ; Hui Ming LI
Biomedical and Environmental Sciences 2024;37(5):494-502
Objective To explore characteristics of clinical parameters and cytokines in patients with drug-induced liver injury(DILI)caused by different drugs and their correlation with clinical indicators. Method The study was conducted on patients who were up to Review of Uncertainties in Confidence Assessment for Medical Tests(RUCAM)scoring criteria and clinically diagnosed with DILI.Based on Chinese herbal medicine,cardiovascular drugs,non-steroidal anti-inflammatory drugs(NSAIDs),anti-infective drugs,and other drugs,patients were divided into five groups.Cytokines were measured by Luminex technology.Baseline characteristics of clinical biochemical indicators and cytokines in DILI patients and their correlation were analyzed. Results 73 patients were enrolled.Age among five groups was statistically different(P=0.032).Alanine aminotransferase(ALT)(P=0.033)and aspartate aminotransferase(AST)(P=0.007)in NSAIDs group were higher than those in chinese herbal medicine group.Interleukin-6(IL-6)and tumor necrosis factor alpha(TNF-α)in patients with Chinese herbal medicine(IL-6:P<0.001;TNF-α:P<0.001)and cardiovascular medicine(IL-6:P=0.020;TNF-α:P=0.001)were lower than those in NSAIDs group.There was a positive correlation between ALT(r=0.697,P=0.025),AST(r=0.721,P=0.019),and IL-6 in NSAIDs group. Conclusion Older age may be more prone to DILI.Patients with NSAIDs have more severe liver damage in early stages of DILI,TNF-α and IL-6 may partake the inflammatory process of DILI.
5.A national questionnaire survey on endoscopic treatment for gastroesophageal varices in portal hypertension in China
Xing WANG ; Bing HU ; Yiling LI ; Zhijie FENG ; Yanjing GAO ; Zhining FAN ; Feng JI ; Bingrong LIU ; Jinhai WANG ; Wenhui ZHANG ; Tong DANG ; Hong XU ; Derun KONG ; Lili YUAN ; Liangbi XU ; Shengjuan HU ; Liangzhi WEN ; Ping YAO ; Yunxiao LIANG ; Xiaodong ZHOU ; Huiling XIANG ; Xiaowei LIU ; Xiaoquan HUANG ; Yinglei MIAO ; Xiaoliang ZHU ; De'an TIAN ; Feihu BAI ; Jitao SONG ; Ligang CHEN ; Yingcai MA ; Yifei HUANG ; Bin WU ; Xiaolong QI
Chinese Journal of Digestive Endoscopy 2024;41(1):43-51
Objective:To investigate the current status of endoscopic treatment for gastroesophageal varices in portal hypertension in China, and to provide supporting data and reference for the development of endoscopic treatment.Methods:In this study, initiated by the Liver Health Consortium in China (CHESS), a questionnaire was designed and distributed online to investigate the basic condition of endoscopic treatment for gastroesophageal varices in portal hypertension in 2022 in China. Questions included annual number and indication of endoscopic procedures, adherence to guideline for preventing esophagogastric variceal bleeding (EGVB), management and timing of emergent EGVB, management of gastric and isolated varices, and improvement of endoscopic treatment. Proportions of hospitals concerning therapeutic choices to all participant hospitals were calculated. Guideline adherence between secondary and tertiary hospitals were compared by using Chi-square test.Results:A total of 836 hospitals from 31 provinces (anotomous regions and municipalities) participated in the survey. According to the survey, the control of acute EGVB (49.3%, 412/836) and the prevention of recurrent bleeding (38.3%, 320/836) were major indications of endoscopic treatment. For primary [non-selective β-blocker (NSBB) or endoscopic therapies] and secondary prophylaxis (NSBB and endoscopic therapies) of EGVB, adherence to domestic guideline was 72.5% (606/836) and 39.2% (328/836), respectively. There were significant differences in the adherence between secondary and tertiary hospitals in primary prophylaxis of EGVB [71.0% (495/697) VS 79.9% (111/139), χ2=4.11, P=0.033] and secondary prophylaxis of EGVB [41.6% (290/697) VS 27.3% (38/139), χ2=9.31, P=0.002]. A total of 78.2% (654/836) hospitals preferred endoscopic therapies treating acute EGVB, and endoscopic therapy was more likely to be the first choice for treating acute EGVB in tertiary hospitals (82.6%, 576/697) than secondary hospitals [56.1% (78/139), χ2=46.33, P<0.001]. The optimal timing was usually within 12 hours (48.5%, 317/654) and 12-24 hours (36.9%, 241/654) after the bleeding. Regarding the management of gastroesophageal varices type 2 and isolated gastric varices type 1, most hospitals used cyanoacrylate injection in combination with sclerotherapy [48.2% (403/836) and 29.9% (250/836), respectively], but substantial proportions of hospitals preferred clip-assisted therapies [12.4% (104/836) and 26.4% (221/836), respectively]. Improving the skills of endoscopic doctors (84.2%, 704/836), and enhancing the precision of pre-procedure evaluation and quality of multidisciplinary team (78.9%, 660/836) were considered urgent needs in the development of endoscopic treatment. Conclusion:A variety of endoscopic treatments for gastroesophageal varices in portal hypertension are implemented nationwide. Participant hospitals are active to perform emergent endoscopy for acute EGVB, but are inadequate in following recommendations regarding primary and secondary prophylaxis of EGVB. Moreover, the selection of endoscopic procedures for gastric varices differs greatly among hospitals.
6.Research Progress on Animal Models of Long Bone Fractures
Guangyuan YAO ; Ping DONG ; Hao WU ; Mei BAI ; Ying DANG ; Yue WANG ; Kai HU
Laboratory Animal and Comparative Medicine 2024;44(3):289-296
Traumatic fractures and stress fractures are common orthopedic diseases,and there is great potential in researching bone turnover,repair,and promotion of fracture healing.Basic medical experiments often use animal models of long bone fractures in limbs to study the mechanisms of various interventions on fracture healing.Fracture healing is a complex process influenced by multiple factors and involves multiple molecules and pathways.Therefore,to explore the mechanisms more deeply,accelerate the translation of results,and improve the clinical efficacy,it is particularly important to choose the appropriate animal fracture modeling methods in experimental research.Based on this,this paper conducts a literature review of animal species and modeling methods commonly used for long bone fracture models in experimental research.It summarizes five methods:bone defect method,physical impact method,mechanical bending method,open osteotomy method,and drilling method.A side-by-side comparison of their advantages,disadvantages,and scope of application is made,aiming to provide suitable fracture models for studyingthe mechanisms of fracture healing interventions.
7.Surgical treatment and prognosis analysis of hilar cholangiocarcinoma
Xiangcheng LI ; Changxian LI ; Hui ZHANG ; Feng CHENG ; Feng ZHANG ; Liyong PU ; Chuanyong ZHANG ; Ke WANG ; Lianbao KONG ; Xiaofeng QIAN ; Donghua LI ; Wenxiong LU ; Ping WANG ; Aihua YAO ; Jianfeng BAI ; Xiaofeng WU ; Ruixiang CHEN ; Xuehao WANG
Chinese Journal of Surgery 2024;62(4):290-301
Objective:To investigate the surgical treatment effect and prognostic factors of hilar cholangiocarcinoma.Methods:This is an ambispective cohort study. From August 2005 to December 2022,data of 510 patients who diagnosed with hilar cholangiocarcinoma and underwent surgical resection at the Hepatobiliary Center of the First Affiliated Hospital of Nanjing Medical University were retrospectively collected. In the cohort,there were 324 males and 186 females,with an age of ( M (IQR)) 63(13)years (range:25 to 85 years). The liver function at admission was Child-Pugh A (343 cases,67.3%) and Child-Pugh B (167 cases,32.7%). Three hundred and seventy-two(72.9%) patients had jaundice symptoms and the median total bilirubin was 126.3(197.6) μmol/L(range: 5.4 to 722.8 μmol/L) at admission. Two hundred and fourty-seven cases (48.4%) were treated with percutaneous transhepatic cholangial drainage or endoscopic nasobiliary drainage before operation. The median bilirubin level in the drainage group decreased from 186.4 μmol/L to 85.5 μmol/L before operation. Multivariate Logistic regression was used to identify the influencing factors for R0 resection,and Cox regression was used to construct multivariate prediction models for overall survival(OS) and disease-free survival(DFS). Results:Among 510 patients who underwent surgical resection,Bismuth-Corlett type Ⅲ-Ⅳ patients accounted for 71.8%,among which 86.1% (315/366) underwent hemi-hepatectomy,while 81.9% (118/144) underwent extrahepatic biliary duct resection alone in Bismuch-Corlett type Ⅰ-Ⅱ patients. The median OS time was 22.8 months, and the OS rates at 1-,3-,5-and 10-year were 72.2%,35.6%,24.8% and 11.0%,respectively. The median DFS time was 15.2 months,and the DFS rates was 66.0%,32.4%,20.9% and 11.0%,respectively. The R0 resection rate was 64.5% (329/510), and the OS rates of patients with R0 resection at 1-,3-,5-and 10-year were 82.5%, 48.6%, 34.4%, 15.2%,respectively. The morbidity of Clavien-Dindo grade Ⅲ-Ⅴ complications was 26.1%(133/510) and the 30-day mortality was 4.3% (22/510). Multivariate Logistic regression indicated that Bismuth-Corlett type Ⅰ-Ⅲ ( P=0.009), hemi-hepatectomy and extended resection ( P=0.001),T1 and T2 patients without vascular invasion (T2 vs. T1: OR=1.43 (0.61-3.35), P=0.413;T3 vs. T1: OR=2.57 (1.03-6.41), P=0.010;T4 vs. T1, OR=3.77 (1.37-10.38), P<0.01) were more likely to obtain R0 resection. Preoperative bilirubin,Child-Pugh grade,tumor size,surgical margin,T stage,N stage,nerve infiltration and Edmondson grade were independent prognostic factors for OS and DFS of hilar cholangiocarcinoma patients without distant metastasis. Conclusions:Radical surgical resection is necessary to prolong the long-term survival of hilar cholangiocarcinoma patients. Hemi-hepatectomy and extended resection,regional lymph node dissection and combined vascular resection if necessary,can improve R0 resection rate.
8.Implementation of surveillance,prevention and control of healthcare-asso-ciated infection in maternal and child healthcare institutions:A nation-wide investigation report
Shuo LI ; Xi YAO ; Hui-Xue JIA ; Wei-Guang LI ; Xun HUANG ; Shu-Mei SUN ; Xi CHENG ; Qing-Lan MENG ; Xiang ZHANG ; Jing-Ping ZHANG ; Ya-Wei XING ; Qing-Qing JIANG ; Lian-Xuan WU ; Bing-Li ZHANG ; Xiao-Jing LIU ; Liu-Yi LI
Chinese Journal of Infection Control 2024;23(3):323-329
Objective To investigate the implementation of surveillance,prevention and control measures for healthcare-associated infection(HAI)in maternal and child healthcare(MCH)institutions,and provide policy evi-dence for optimizing HAI prevention and control in MCH institutions.Methods Stratified sampling was conducted among the MCH institutions at provincial,municipal and county levels in 8 provinces/autonomous regions.A uni-fied questionnaire was designed and the online survey was conducted through"Questionnaire Star".Results The data from 123 MCH institutions were included in the analysis.90.24%of the MCH institutions carried out compre-hensive surveillance on HAI.The ratios of MCH institutions which implemented targeted surveillance on HAI in neonatal intensive care unit(NICU),surgical site infection,multidrug-resistant organisms(MDROs)and HAI in intensive care units(non-NICU excluded)were 89.66%,85.96%,80.77%,and 74.19%,respectively.51.22%MCH institutions adopted information surveillance system on HAI cases.94.31%MCH institutions carried out surveillance on hand hygiene compliance.Over 90%MCH institutions carried out surveillance on environment hy-giene in high-risk departments.71.54%MCH institutions conducted centralized cleaning,disinfection,sterilization and supply for reusable medical instruments in the central sterile supply department(CSSD).Over 90%MCH insti-tutions established three-level pre-examination triage systems.86.18%set up transitional wards.MCH institutions generally adopted a management model with established effective communication,full appointment visits,and sepa-rate visits for special medical groups,such as registered pregnant women,high-risk newborns,healthcare groups,and long-term rehabilitation patients.However,the ratio of institutions conducting on-line follow-up visits was less than 50%.Conclusion MCH institutions have generally carried out comprehensive and targeted surveillance on HAI.Information surveillance need to be facilitated.Hand hygiene and environmental hygiene surveillance has been popularized to a certain extent at all levels of MCH institutions.The cleaning,disinfection,sterilization,and supply processes of reusable medical devices in a few MCH institutions are not standardized.Special medical populations get effective management.On-line healthcare is to be further promoted.
9.Value of left ventricular shape index and eccentricity index of gated myocardial perfusion imaging in the evaluation of left ventricular remodeling in patients with myocardial infarction
Xiaoyi XI ; Luxia WANG ; Qi YAO ; Shihao HUANGFU ; Yuxin XIAO ; Zhifang WU ; Ping WU ; Li LI ; Rui YAN ; Yuetao WANG ; Minfu YANG ; Sijin LI
Chinese Journal of Nuclear Medicine and Molecular Imaging 2024;44(1):6-11
Objective:To investigate the clinical value of left ventricular shape index (SI) and eccentricity index (EI) in evaluating left ventricular remodeling.Methods:A retrospective analysis was performed on 324 patients (264 males, 60 females, age (62.5±11.8) years) diagnosed with myocardial infarction (MI) and 113 healthy controls (HC; 47 males, 66 females, age (57.8±10.7) years) who received gated myocardial perfusion imaging (GMPI) in First Hospital of Shanxi Medical University from January 2016 to September 2020. SI (end-diastolic SI (EDSI), end-systolic SI (ESSI)), EI and left ventricular function parameters (end-diastolic volume (EDV), end-systolic volume (ESV), left ventricular ejection fraction (LVEF), summed motion score (SMS), summed thickening score (STS), peak ejection rate (PER) and peak filling rate (PFR)) were obtained by quantitative gated SPECT (QGS) software. Propensity score (PS) inverse probability of treatment weighting (IPTW) was used to balance the intergroup covariates. The differences and correlations of EDSI, ESSI, EI and left ventricular function parameters between patients in MI group and HC group were analyzed. ROC curve analysis was used to evaluate the values of EDV, EDSI, ESSI and EI alone and in combination in the assessment of left ventricular systolic function impairment. Data were analyzed by independent-sample t test, Pearson correlation and Spearman rank correlation analyses, and Delong test. Results:After IPTW, EDSI and ESSI in MI group ( n=319) were higher than those in HC group ( n=133; EDSI: 0.66±0.09 vs 0.60±0.06; ESSI: 0.59±0.11 vs 0.47±0.07; t values: 8.05, 14.67, both P<0.001), and EI was lower than that in HC group (0.81±0.06 vs 0.85±0.03; t=-8.93, P<0.001). In both groups, there were significant correlations between EDSI and ESSI ( r values: 0.928, 0.873), between EDSI, ESSI and EI ( r values: from -0.831 to -0.641), between EDSI, ESSI and LVEF ( r values: from -0.627 to -0.201), between ESSI and EDV, ESV and SMS ( rs values: 0.336-0.584), between ESSI and -PER, PFR ( rs values: from -0.406 to -0.402, r values: from -0.352 to -0.325) (all P<0.01). ROC curve analysis showed that EDV (AUC: 0.895) and ESSI (AUC: 0.839) had the highest efficacy in evaluating left ventricular systolic function impairment in MI group and HC group, respectively. EDV-EDSI-ESSI-(1-EI) had higher efficacy in the assessment of impaired left ventricular systolic function in MI group (AUC: 0.956), which was higher than that of EDV or EDV-EDSI or EDV-ESSI or EDV-(1-EI) ( z values: from -2.64 to -2.18, P values: 0.008-0.029); EDV-EDSI-ESSI-(1-EI) also had high efficacy in HC group (AUC: 0.911), which was higher than that of EDV or EDV-EDSI or EDV-(1-EI) ( z values: from -2.60 to -2.43, P values: 0.009-0.015). Conclusions:In MI patients, the increase of SI and the decrease of EI indicate the increase of left ventricular sphericity and the aggravation of left ventricular remodeling. SI and EI have certain clinical application values in evaluating left ventricular morphology, predicting left ventricular remodeling and left ventricular systolic function impairment.
10.Determination of four odorous substances in water by purge and trap-gas chromatography-tandem mass spectrometry
Kun CHEN ; Fanghong CAO ; Xiaoxia CHEN ; Ling YANG ; Minfang YAO ; Ping SONG ; Pinggu WU
Journal of Environmental and Occupational Medicine 2024;41(10):1180-1185
Background With the events reporting on odors in drinking water, odorous substances in water have become a hot topic in water quality analysis. Due to the low concentration of the odor threshold and the complexity of the odor components in water, it is difficult to make accurate qualitative and quantitative analysis. So it is necessary to develop a highly sensitive and accurate qualitative and quantitative analysis method. Objective To establish a method for simultaneous determination of four odorous substances, including dimethyl disulfide, dimethyl trisulfide, 2-methylisoborneol, and geosmin in water by purge and trap-gas chromatography-tandem mass spectrometry. Methods A certain amount of water sample was stored in the sample vial of a purge and trapinstrument. Through nitrogen purging, the odorous substances in water were purged out and enriched in the trap. Subsequently, the odorous substances were rapidly released at high temperatures after heating the trap, and then carried by carrier gas into gas chromatograph. After temperature programming, the substances were separated by an Agilent DB-624 capillary chromatographic column (30 m×0.25 mm, 1.4 μm) and determined by tandem mass spectrometry in multiple reaction monitoring modes, with internal standard method for quantification. The current project optimized purge time, sodium chloride concentration in water sample, desorption temperature, desorption time, and split ratio during the experimental process. Under the optimized experimental conditions, the standard curve, detection limit, and quantification limit were validated. Recovery tests with spiking concentrations of 5.0, 10.0, 30.0, 80.0 ng·L−1 and precision tests were conducted on water samples. Finally, the established method was applied to detect odorous substances in source water, finished water, and pipeline water in Deqing County of Huzhou City. Result After the optimization, the purge time was 20 min, the desorption temperature was 280 ℃, the desorption time was 2 min, the split ratio was 10∶1, and no sodium chloride was added during the purge process. Under the optimized experimental conditions, the calibration curves for the four odorous substances showed an excellent linearity in the range of 1 to 100 ng·L−1 (R>0.999), with 0.3 ng·L−1 limit of detection and 1.0 ng·L−1 limit of quantitation. The average recoveries were from 85.5% to 102.4% and relative standard deviations (RSD) from 1.6% to 5.2%. After applying this method to detect local source water, finished water, and pipeline water, it was found that the positive rates of 2-methylisoborneo, and geosmin were relatively high, while the positive rates of dimethyl disulfide and dimethyl trisulfide were relatively low. Only one sample of source water tested positive for dimethyl disulfide, and all samples were negative for dimethyl trisulfide. Conclusion Combined with the superiority of purge and trap and tandem mass spectrometry, the method has the advantages of easy to perform, strong anti-interference ability, good accuracy and precision, which meet the limit requirements of the four odorous substances in the expanded indices and reference indices of Hygienic standards for drinking water (GB 5749-2022). It also provides technical support for water quality assessment and analysis of odorous substances.

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