1.Epigenetic mechanism of Diwu Yanggan Capsule in improving liver regeneration microenvironment in a rat model of liver cancer
Minggang WANG ; Jiamei DONG ; Zhihua YE ; Xiang GAO ; Qi CHEN ; Xiaoqiao YU ; Hanmin LI
Journal of Clinical Hepatology 2026;42(2):362-371
ObjectiveTo investigate the epigenetic mechanism of Diwu Yanggan Capsule in improving liver regeneration microenvironment in a rat model of liver cancer by regulating DNA methylation, and to provide a basis for scientific clinical medication. MethodsA total of 48 specific pathogen-free Sprague-Dawley rats were divided into normal group, model group, and Diwu Yanggan Capsule group using a random number table, with 16 rats in each group. The Solt-Farber two-step method was used to establish a rat model of liver cancer. The rats in the Diwu Yanggan Capsule group were given Diwu Yanggan Capsule at a dose of 750 mg/kg/d by gavage, and those in the normal group and the model group were given an equal volume of normal saline by gavage. Liver tissue samples were collected from each group of rats after 16 weeks of continuous intervention; DNA methylation chips were used to analyze the change in DNA methylation in liver tissue, and gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were used for data analysis. In addition, the MeDIP-PCR technique was used to detect the changes in candidate differentially methylated genes such as YWHAB, ADCK2, ERLIN2, SEMA3B, and TPH2 in the liver tissue of rats, and Western blot and RT-qPCR were used to verify the expression of key methylated genes. The independent-samples t test was used for comparison of continuous data between two groups, and a one-way analysis of variance was used for comparison between multiple groups, while the least significant difference t-test was used for further comparison between two groups. ResultsThe DNA methylation chip analysis showed that compared with the normal group, the model group had significant methylation changes in the promoter region of 2 422 genes in liver tissue of rats. The GO functional enrichment analysis and the KEGG pathway enrichment analysis showed that these differentially methylated genes were significantly enriched in metabolic pathways such as steroid hormone biosynthesis and drug metabolism-cytochrome P450. Compared with the model group, the Diwu Yanggan Capsule group had significant reversal of promoter methylation in 1 650 genes, and the KEGG enrichment analysis showed that these genes were mainly involved in the pathways closely associated with cell proliferation, apoptosis, and microenvironment regulation, such as the calcium ion signaling pathway, the cAMP signaling pathway, and the extracellular factor signaling pathway. Compared with the model group, the Diwu Yanggan Capsule group had a significant increase in the promoter methylation level of the ADCK2 gene (P<0.05) and significant reductions in the promoter methylation levels of the ERLIN2 and TPH2 genes (all P<0.05). Compared with the model group, the Diwu Yanggan Capsule group had significant reductions in the mRNA expression levels and the protein expression levels of the ADCK2 (all P<0.05). ConclusionAbnormal DNA methylation in liver tissue participates in the development and progression of liver cancer. The effect of Diwu Yanggan Capsule on DNA methylation level is an important epigenetic mechanism for its effect in the prevention and treatment of liver cancer.
2.A Personalized Brain-computer Interface Paradigm and Decoding Method for The Objective Evaluation of Auditory Frequency Difference Limen
Sheng-Ye LI ; Xiao-Lin XIAO ; Shi-Hang YU ; Bei-Bei ZHANG ; Xing-Wei AN ; Min-Peng XU ; Dong MING
Progress in Biochemistry and Biophysics 2026;53(7):1927-1941
ObjectiveThe frequency difference limen (FDL) serves as a fundamental metric utilized for effectively quantifying the precise perceptual capabilities of the central auditory system. However, traditional measurement methods rely heavily on the active behavioral responses of subjects and are consequently highly susceptible to the negative influence of confounding subjective factors. Furthermore, existing research paradigms frequently employ uniform stimulus configurations that overlook critical individual perceptual differences. Based on brain-computer interface (BCI) technology, this comprehensive study aims to establish an objective and quantitative evaluation method for auditory frequency discrimination by systematically analyzing and decoding the specific neural responses elicited at the exact threshold state. MethodsWe designed a personalized rapid serial auditory presentation (RSAP) paradigm customized based on each individual’s precise FDL. A cohort of eleven healthy participants was recruited to evaluate the paradigm using pure-tone sequences at a baseline frequency of 4 000 Hz. This experimental paradigm simulates a realistic auditory perception environment through the continuous presentation of acoustic stimuli, thereby allowing for an in-depth investigation into the specific neural representations evoked by weak frequency deviations at the threshold state. Given that auditory stimulus-evoked response features exhibit complex and differentiated spatiotemporal distribution patterns across multiple frequency domains, this study further deeply integrates the cross-scale feature interaction module with the dynamic spatiotemporal attention allocation strategy, innovatively proposing the Multi-Scale Spatial-Temporal Dual Attention Network (MS-STAMNet). Specifically, the network constructs parallel processing branches with multiple receptive fields and introduces a dynamic adaptive weighting strategy to precisely localize core neural activity signals, further deeply integrating multi-scale information through cross-branch feature information interaction to achieve robust single-trial decoding of weak auditory evoked responses. ResultsThe comprehensive electrophysiological data analysis demonstrated that subtle auditory frequency deviation stimuli presented at the threshold level successfully elicited pronounced N2 and P3 event-related potential features, reflecting pre-attentive mismatch detection and subsequent cognitive evaluation, which were prominently distributed over the frontal, central, and temporal regions of the scalp. In the complex time-frequency domain, the extracted neural response characteristics exhibited distinct, statistically significant event-related synchronization within both the low-frequency δ and θ frequency bands, which was simultaneously accompanied by a widespread, prominent event-related desynchronization within the higher α band. A comparative analysis of model performance demonstrated that MS-STAMNet achieved an average unweighted average recall (UAR) of (69.67±6.12)% and area under the curve (AUC) of 0.761 8±0.07, significantly outperforming the established baseline models such as EEGNet and PLNet. Furthermore, a distinct dissociation phenomenon was verified between neural decoding and behavioral performance through regression analysis (R2=0.016, P=0.709), indicating that this model can effectively capture the implicit features of subtle frequency deviations, even when they fail to trigger explicit conscious responses. Additionally, attention weight visualization analysis further reveals the highly accurate focus of the network on key features concentrated over the bilateral temporal and fronto-parietal regions. ConclusionThis study systematically and comprehensively uncovers the multi-dimensional spatiotemporal evolutionary patterns of complex neural responses processing subtle acoustic variations under long-sequence threshold auditory stimulation. Concurrently, it verifies the efficacy and robustness of the proposed MS-STAMNet architecture in accurately deciphering weak, single-trial electroencephalogram signals amidst complex background noise. Ultimately, these neurophysiological and algorithmic findings lay a solid theoretical and methodological foundation for the objective and quantitative evaluation of individual auditory cognitive capabilities in clinical applications, transcending the fundamental limitations of traditional behavioral paradigms and providing robust technical support for future auditory research and related clinical assessments.
3.Analysis of knowledge, attitude, and practice levels regarding health protection against air pollution and related factors among Chinese primary school students
Chinese Journal of School Health 2026;47(7):958-961
Objective:
To assess the current status of knowledge, attitude, and practice (KAP) regarding health protection against air pollution among primary school students in China, and to analyze the impacts of fine particulate matter (PM 2.5 ) exposure, family, and individual factors on KAP levels, so as to provide empirical basis for implementing targeted interventions.
Methods:
Using stratified cluster random sampling method, a questionnaire survey was conducted among 19 297 primary school students from third to fifth grade across 30 provinces (autonomous regions and municipalities directly under the central government) in China in 2024. The questionnaire was developed based on the Technical Guidelines for the Assessment of Civic Environmental and Health Literacy (Trial), and encompasses three dimensions:knowledge, attitude, and practice. Spearman correlation analysis, Chi-square test, multivariate Logistic regression, and Bootstrap mediation effect test was applied for data analysis.
Results:
The overall mean KAP score for health protection against air pollution among primary school students was (79.73±13.53), with an adequacy rate of 80.47% ( n =15 528). The dimension scores for knowledge, attitude, and practice were (41.34±8.01, 16.43± 2.61 ), and (21.97±5.71), respectively. Knowledge was positively correlated with attitude and practice, and attitude was positively correlated with practice ( r =0.51, 0.35, 0.32, all P <0.01). Multivariate Logistic regression showed that the northeast region ( OR =2.36, 95% CI =2.02-2.75), having parents with a bachelor s degree or higher ( OR =4.76, 95% CI =2.71-8.37), living with both parents ( OR =1.33, 95% CI =1.15-1.55), being in the fifth grade ( OR =1.22, 95% CI =1.11-1.33), outdoor PM 2.5 level exceeding standard limits at the survey site ( OR =1.25, 95% CI =1.16-1.34), history of allergy ( OR =1.47, 95% CI =1.31-1.64), and wearing masks during heavily polluted weather ( OR =1.19, 95% CI =1.07-1.31) were promoting factors for KAP adequacy rate (all P <0.05). Conversely, obesity was a detrimental factor ( OR =0.78, 95% CI =0.69-0.88, all P <0.05).
Conclusions
Primary school students in China exhibit a favorable KAP level regarding health protection against air pollution, though regional, familial, and individual disparities persist. Exposure to PM 2.5 levels exceeding standard limits exerts a direct positive effect on enhancing health protection literacy. Future efforts should focus on the western region, families with lower educational attainment children to implement tailored, stratified interventions.
4.Association of urine cadmium levels with thyroid hormone levels among middle-aged and older adults aged 40-89 years in selected areas of China
Changzi WU ; Xiaochen WANG ; Yue CHEN ; Zheng LI ; Yi ZHANG ; Yuan WEI ; Bing WU ; Wenli ZHANG ; Zhengxiong YANG ; Xiaojie DONG ; Ruiting HAO ; Xiu YE ; Luxi WEI ; Yingli QU ; Haiyan CHU ; Yuebin LYU ; Ying ZHU ; Dongqun XU ; Xiaoming SHI
Chinese Journal of Preventive Medicine 2025;59(2):209-215
Objective:To explore the relationship between urinary cadmium levels and thyroid hormone levels in people aged 40-89 years old in selected areas of China.Methods:Based on the "Investigation of the Impact of Soil Quality of Agricultural Land on Human Health in Typical Areas" project from October 2019 to August 2020, a multi-stage stratified random sampling method was used to include 6 588 middle-aged and older adults aged 40-89. Demographic characteristics, dietary frequency and disease status were collected through the questionnaire and physical examination. Urinary cadmium and urinary creatinine were detected by random midstream urine. Fasting venous blood was collected for the detection of Triiodothyronine (T3) and Thyroxine (T4). The linear mixed effects model was used to explore the association of urine cadmium levels with thyroid hormone levels. Its dose-response relationship was explored by using the restricted cubic spline.Results:The age of the subjects was (63.48±12.18) years, with males accounting for 51.28%. The M ( Q 1,Q 3) of urinary cadmium level, T3 and T4 was 2.48 (1.36, 4.42) μg/g·creatinine, (1.96±0.51) nmol/L and (113.75±29.11) nmol/L, respectively. The linear mixed effects model showed that the changes of T3 and T4 were 0.027 (0.009, 0.044) nmol/L and 2.019 (1.084, 2.953) nmol/L for each one-unit increase (natural logarithm transformed) of urinary cadmium. The restricted cubic spline showed that there was a positive nonlinear association between urinary cadmium and T3 as well as T4 (all Pnonlinear<0.05). Conclusion:In selected areas of China, the urinary cadmium level of middle-aged and older adults aged 40-89 years is positively associated with T3 and T4.
5.Expert consensus on visualized tele-round and quality control management based on the improvement of clinical practice ability
Wanhong YIN ; Xiaoting WANG ; Ran ZHOU ; Dawei LIU ; Yan KANG ; Yaoqing TANG ; Xiaochun MA ; Jianguo LI ; Zhenjie HU ; Haitao ZHANG ; Wei HE ; Lixia LIU ; Wenjin CHEN ; Ran ZHU ; Jun WU ; Hongmin ZHANG ; Lina ZHANG ; Wenzhao CHAI ; Shihong ZHU ; Wangbin XU ; Rongqing SUN ; Xiangyou YU ; Tianjiao SONG ; Ying ZHU ; Hong REN ; Ai SHANMU ; Qing ZHANG ; Wei FANG ; Xiuling SHANG ; Liwen LYU ; Shuhan CAI ; Xin DING ; Heng ZHANG ; Guang FENG ; Lipeng ZHANG ; Bo HU ; Dong ZHANG ; Weidong WU ; Feng SHEN ; Xiaojun YANG ; Zhenguo ZENG ; Qibing HUANG ; Xueying ZENG ; Tongjuan ZOU ; Milin PENG ; Yulong YAO ; Mingming CHEN ; Hui LIAN ; Jingmei WANG ; Yong LI ; Feng QU ; Gang YE ; Rongli YANG ; Xiukai CHEN ; Suwei LI ; Juxiang WANG ; Yangong CHAO
Chinese Journal of Internal Medicine 2025;64(2):101-109
Turning to critical illness is a common stage of various diseases and injuries before death. Patients usually have complex health conditions, while the treatment process involves a wide range of content, along with high requirements for doctor′s professionalism and multi-specialty teamwork, as well as a great demand for time-sensitive treatments. However, this is not matched with critical care professionals and the current state of medical care in China. Telemedicine, which shortens the distance of medical professionals and the gap of disease diagnosis and treatments in various regions through electronic information, can effectively solve the current problem. Therefore, there is an urgent need to develop a standardized, high-quality visualization telemedicine round system .Therefore, experts have been organized to search domestic and foreign literature on telemedicine round for critically ill patients and to form this consensus based on clinical experiences so as to further improve the level of critical care treatments in regions.
6.Clinical manifestations and prognostic analysis of four patients with thyroid peroxidase gene mutations
Rongguang PENG ; Jie ZHANG ; Chenchen DONG ; Rulai HAN ; Lingyang MENG ; Haorong LI ; Lei JIN ; Wenzhong ZHOU ; Liyun SHEN ; Yulin ZHOU ; Jiqi YAN ; Shu WANG ; Lei YE
Chinese Journal of Endocrinology and Metabolism 2025;41(1):46-53
Objective:To examine the clinical features and genetic profiles of patients with thyroid peroxidase(TPO) gene mutations and provide diagnostic guidance for clinicians.Methods:A retrospective review of four patients with TPO mutations treated at Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, from January 2014 to December 2023. Data on demographics, clinical manifestation, genotypes, treatment, and prognosis of these patients were analyzed.Results:Two males and two females, aged 13 to 27 years at diagnosis, presented with goiter as the initial symptom, with three cases menifesting during puberty. Laboratory findings showed mildly elevated or upper-limit-normal serum thyroid-stimulating hormone(TSH) levels, significantly increased free triiodothyronine/free thyroxine(FT 3/FT 4) ratios, and elevated thyroglobulin(TG) levels. Genetic testing revealed compound heterozygous pathogenic or likely pathogenic TPO mutations. Despite regular levothyroxine(L-T 4) therapy, goiter persisted. Three patients required thyroidectomy due to cosmetic or compressive symptoms, with pathology showing follicular hyperplasia. Conclusion:TPO mutations are characterized by adolescent-onset goiter, elevated FT 3/FT 4 ratios, and normal to high TSH. Genetic testing confirms the diagnosis. L-T 4 offers limited improvement, and surgery is often needed.
7.Guideline for Adult Weight Management in China
Weiqing WANG ; Qin WAN ; Jianhua MA ; Guang WANG ; Yufan WANG ; Guixia WANG ; Yongquan SHI ; Tingjun YE ; Xiaoguang SHI ; Jian KUANG ; Bo FENG ; Xiuyan FENG ; Guang NING ; Yiming MU ; Hongyu KUANG ; Xiaoping XING ; Chunli PIAO ; Xingbo CHENG ; Zhifeng CHENG ; Yufang BI ; Yan BI ; Wenshan LYU ; Dalong ZHU ; Cuiyan ZHU ; Wei ZHU ; Fei HUA ; Fei XIANG ; Shuang YAN ; Zilin SUN ; Yadong SUN ; Liqin SUN ; Luying SUN ; Li YAN ; Yanbing LI ; Hong LI ; Shu LI ; Ling LI ; Yiming LI ; Chenzhong LI ; Hua YANG ; Jinkui YANG ; Ling YANG ; Ying YANG ; Tao YANG ; Xiao YANG ; Xinhua XIAO ; Dan WU ; Jinsong KUANG ; Lanjie HE ; Wei GU ; Jie SHEN ; Yongfeng SONG ; Qiao ZHANG ; Hong ZHANG ; Yuwei ZHANG ; Junqing ZHANG ; Xianfeng ZHANG ; Miao ZHANG ; Yifei ZHANG ; Yingli LU ; Hong CHEN ; Li CHEN ; Bing CHEN ; Shihong CHEN ; Guiyan CHEN ; Haibing CHEN ; Lei CHEN ; Yanyan CHEN ; Genben CHEN ; Yikun ZHOU ; Xianghai ZHOU ; Qiang ZHOU ; Jiaqiang ZHOU ; Hongting ZHENG ; Zhongyan SHAN ; Jiajun ZHAO ; Dong ZHAO ; Ji HU ; Jiang HU ; Xinguo HOU ; Bimin SHI ; Tianpei HONG ; Mingxia YUAN ; Weibo XIA ; Xuejiang GU ; Yong XU ; Shuguang PANG ; Tianshu GAO ; Zuhua GAO ; Xiaohui GUO ; Hongyi CAO ; Mingfeng CAO ; Xiaopei CAO ; Jing MA ; Bin LU ; Zhen LIANG ; Jun LIANG ; Min LONG ; Yongde PENG ; Jin LU ; Hongyun LU ; Yan LU ; Chunping ZENG ; Binhong WEN ; Xueyong LOU ; Qingbo GUAN ; Lin LIAO ; Xin LIAO ; Ping XIONG ; Yaoming XUE
Chinese Journal of Endocrinology and Metabolism 2025;41(11):891-907
Body weight abnormalities, including overweight, obesity, and underweight, have become a dual public health challenge in Chinese adults: overweight and obesity lead to a variety of chronic complications, while underweight increases the risks of malnutrition, sarcopenia, and organ dysfunction. To systematically address these issues, multidisciplinary experts in endocrinology, sports science, nutrition, and psychiatry from various regions have held multiple weight management seminars. Based on the latest epidemiological data and clinical evidence, they expanded the guideline to include assessment and intervention strategies for underweight, in addition to the core content of obesity management. This guideline outlines the etiological mechanisms, evaluation methods, and multidimensional management strategies for overweight and obesity, covering key areas such as diagnosis and assessment, medical nutrition therapy, exercise prescription, pharmacological intervention, and psychological support. It is intended to provide a scientific and standardized approach to weight management across the adult population, aiming to curb the rising prevalence of obesity, mitigate complications associated with abnormal body weight, and improve nutritional status and overall quality of life.
8.Study on the effect of differently automatic normal tissue objective weights of Eclipse planning system on intensity modulated radiation therapy for abdominal tumor
Weijie DONG ; Chunqiang WANG ; Linni WANG ; Shuang HAN ; Ye ZHANG ; Yixin LI
China Medical Equipment 2025;22(2):9-14
Objective:To compare the effects of different automatic normal tissue objective(NTO)weights(WNTO)of Eclipse planning system on intensity modulated radiation therapy(IMRT)of fixed field for abdominal tumor.Methods:Twenty patients with rectal cancer and twenty patients with cervical cancer who received radiotherapy in The Second People's Hospital of Huludao from September 2022 to January 2024 were selected.5 groups of different plans[WNTO20,40,60,80 and 100]were respectively formulated for each patient.Among of them,the WNTO20 plan was control group,and other 4 groups were respectively WNTO40 group,WNTO60 group,WNTO80 group and WNTO100 group.Then,the differences in dosimetry and monitor units(MU)among 5 groups of plans were compared.Results:In the WNTO 80 and 100 groups of patients with rectal cancer,the conformation index(CI)values of target regions of them were respectively 1.02±0.04 and 1.00±0.03,all of which approached to 1,and the CI values of two groups were lower than that of control group,and the differences were statistically significant(t=15.986,18.422,P<0.05).The homogeneity index(HI)of WNTO 80 and 100 groups were respectively 0.09±0.12 and 0.10±0.14,which were higher than that of control group,and the differences were statistically significant(t=-1.371,-1.463,P<0.05).The 52Gy dose volume(Vmax52)of small intestine of the two groups were respectively(4.48±14.49)and(4.77±10.47)cm3,which were higher than that of control group,and the differences were statistically significant(t=-1.360,-2.005,P<0.05).The 30 Gy dose volume percentage(V30 Gy)values of the right femoral heads of the two groups were respectively(12.28±4.57)%and(10.96±4.17)%,which were lower than that of control group,and the differences were statistically significant(t=6.893,6.75,P<0.05).The 30 Gy dose volume percentage(V30 Gy)values of the left femoral head of the two groups were respectively(11.57±4.41)%and(10.17±3.78)%,which were lower than that of control group,and the differences were statistically significant(t=6.782,5.963,P<0.05).The MU value of WNTO100 group was(1254±93)MU,which was higher than that of control group,and the difference was statistically significant(t=-3.741,P<0.05).In the WNTO 80 and 100 groups of patients with cervical cancer,the CI values of target regions of them were respectively 1.03±0.32 and 1.02±0.03,all of which approached to 1,and the CI values of the two groups were lower than those of control group,and the differences were statistically significant(t=20.069,19.475,P<0.05).The HI values of them were respectively 0.07±0.05 and 0.08±0.01,which were higher than that of control group,and the differences were statistically significant(t=-12.445,-19.478,P<0.05).The V30 Gy values of the right femoral heads of the two groups were respectively(16.11±4.71)%and(14.90±4.56)%,which were lower than that of control group,and the differences were statistically significant(t=7.875,8.020,P<0.05).The V30 Gy values of the left femoral head of the two groups were respectively(15.21±3.71)%and(13.93±3.77)%,which were lower than that of control group,and the differences were statistical significance(t=7.617,7.436,P<0.05).The Vmax52 of small intestine of the two groups were respectively(0.82±1.10)and(4.47±8.81)cm3,which were higher than that of control group,and the difference was statistically significant(t=-2.985,-2.388,P<0.05).Conclusion:The WNTO80 is recommended for IMRT plan of radiotherapy on abdominal tumor,which can more quickly and better meet the assessment conditions of IMRT plan.
9.Study on the current situation and influencing factors of nutritional risk in children in PICU
Lian-Ye LI ; Ying-Jie DUAN ; Guang-Yu LI ; Qi LI ; Mao MAO ; Yu TIAN ; Dong-Xue LÜ ; Wei ZHANG ; Xin-Hui LIU
Parenteral & Enteral Nutrition 2025;32(1):23-28
Objective:To investigate the nutritional risk status of children in PICU and analyze its influencing factors.Methods:From July 2021 to February 2023,all children aged 1 to 18 years admitted to PICU of Beijing Children's Hospital were investigated by using the pediatric Yorkhill Malnutrition Scoring tool(PYMS)and the clinical data questionnaire.Results:A total of 492 children in PICU were enrolled.The first nutritional risk screening results showed that there were 32 cases of no/low nutritional risk(6.5%),76 cases of medium risk(15.4%),and 384 cases of high risk(78.1%).The incidence of medium/high nutritional risk was as high as 93.5%.The PYMS score of nutritional risk in PICU was(2.61±1.42).The results of multiple linear regression analysis showed that weight,fever time before admission,white blood cells,body mass index,primary diagnosis,father's education,and diet before illness were the main influencing factors of nutritional risk of children in PICU(P<0.05).Conclusion:Children in PICU are in a state of high nutritional risk.It is suggested that children in PICU should carry out nutritional screening in a standardized manner,identify children with high nutritional risk and its influencing factors early.To actively conduct nutritional assessment and nutritional intervention could improve the clinical outcome of children in PICU.
10.Simultaneous Determination of Four Off-flavors in Freshwater Fish by Gas Chromatography-Mass Spectrometry Combined with Silica Solid Phase Extraction
Liang-Liang TIAN ; Dong-Mei HUANG ; Yuan WANG ; Xuan-Yun HUANG ; Yong-Fu SHI ; Hong-Li YE
Chinese Journal of Analytical Chemistry 2025;53(7):1158-1166
An effective method for simultaneously detecting four semivolatile earthy-musty odors in freshwater fish by gas chromatography-mass spectrometry(GC-MS)was developed.The concurrent extraction of geosmin(GSM),2-methylisoborneol(MIB),2-isopropyl-3-methoxypyrazine(IPMP),and 2-isobutyl-3-methoxypyrazine(IBMP)in fish tissue was conducted with n-hexane.The optimized QuEChERS material was implemented,and it was found that C18,primary secondary amine(PSA)and MgSO4 could adsorb the target analytes in n-hexane.So only the graphitized carbon black(GCB)could be used to purify the extraction.The adsorption rates of different materials for the four kinds of odors materials were explored in n-hexane and ethyl acetate.The experimental results revealed that the adsorption rates of silica for the four targets were 99.5%-100%in n-hexane and 0.7%-5.0%in ethyl acetate respectively.Then the silica solid phase extraction(SPE)method was utilized to eluent the compounds using 1.0 mL n-hexane/ethyl acetate in different proportions.The results of the comparative analysis demonstrated that n-hexane/ethyl acetate(4∶1,V/V)was the optimized eluent.Based on the obtained results,n-hexane extraction and GCB purification combined with silica SPE were used to isolate GSM,MIB,IPMP and IBMP from fish and the method was validated.It was found that the method showed good linearity in the range of 0.5-200 ng/mL,and with detection limits of 0.6 μg/kg for GSM and MIB,0.2 μg/kg for IPMP and IBMP.The limits of quantitation(LOQ)were 1.0 μg/kg for GSM and MIB,0.6 μg/kg for IPMP and IBMP.Good recoveries(77.5%-112.0%)and relative standard deviations(1.56%-9.42%)were also obtained.The use of silica SPE greatly mitigated the issue that the off-flavor compounds were easily lost in the gas blowing concentration process.There was no cross contamination in this method because the sample pretreatments were conducted separately,which was different with the most commonly used HS-SPME method for detecting semi-volatile substances.The sensitivity of this method was high enough to produce good quantitative results below the odor thresholds of the examined off-flavor compounds.


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