1.Establishment and Preliminary Analysis of GP73 Interactome Using Proximity-dependent Labeling Technology
Mu-Yi LIU ; Chang ZHANG ; Meng-Xin YANG ; Xin-Long YAN ; Lu-Ming WAN ; Cong-Wen WEI
Progress in Biochemistry and Biophysics 2026;53(3):711-723
ObjectiveProtein-protein interactions (PPIs) are fundamental to the execution of biological functions within living cells. However, traditional biochemical methods, such as co-immunoprecipitation (Co-IP), often fail to capture transient, weak, or membrane-associated interactions due to the stringent detergent requirements for cell lysis. Proximity labeling (PL) has emerged in recent years as a transformative technology for mapping the proteomes of specific subcellular compartments and identifying dynamic interactomes in situ. Golgi protein 73 (GP73, also known as GOLPH2), a resident type II Golgi transmembrane protein, is a well-recognized clinical biomarker for liver diseases, including hepatocellular carcinoma (HCC). Despite its clinical significance, the comprehensive physiological and pathological functions of GP73 remain partially understood. This study aims to establish an APEX2-mediated proximity labeling system specifically targeting GP73 to map its interactome in a living cellular environment, thereby providing new insights into its molecular roles and regulatory mechanisms. MethodsTo achieve spatial specificity, we first constructed a stable cell line expressing a fusion protein consisting of GP73 and the engineered soybean peroxidase APEX2. The localization of the GP73-APEX2 fusion protein was validated to ensure it correctly targeted the Golgi apparatus. The proximity labeling reaction was initiated by incubating the cells with biotin-phenol (BP) for 30 min, followed by a brief (1 min) treatment with1 mmol/L hydrogen peroxide (H2O2). This catalytic reaction converts BP into highly reactive, short-lived biotin-phenoxyl radicals that covalently attach to endogenous proteins within a small labeling radius of the GP73-APEX2 enzyme. Subsequently, the cells were quenched, and biotinylated proteins were enriched using high-affinity streptavidin-coated magnetic beads. The captured “neighbor” proteins were subjected to on-bead digestion and analyzed via liquid chromatography-tandem mass spectrometry (LC-MS/MS) for high-throughput identification. Rigorous bioinformatics analysis, including Gene Ontology (GO) enrichment, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, and protein-protein interaction network mapping, was performed to interpret the biological significance of the identified candidates. ResultsOur results demonstrate the successful establishment of a robust and sensitive APEX2-based proximity labeling system for GP73. We identified a total of 95 high-confidence interacting proteins that were significantly enriched in the GP73 proximity proteome compared to control groups. Bioinformatics analysis revealed that these interactors were predominantly associated with biological processes such as vesicular transport, protein localization, and, most notably, molecular functions related to “ribosome binding” and “translation regulation”. This suggested an unexpected role for the Golgi-resident GP73 in the cellular translation machinery. To validate these findings, we performed targeted biochemical assays which confirmed a direct interaction between GP73 and the subunits of the eukaryotic translation initiation factor 3 (eIF3) complex, specifically EIF3G and EIF3I. Furthermore, functional validation using the surface sensing of translation (SUnSET) assay—a non-radioactive method to monitor protein synthesis—revealed that the overexpression of GP73 significantly promoted global protein translation levels in the cell, whereas its depletion or inhibition resulted in reduced translation efficiency. ConclusionThis study successfully utilized APEX2-mediated proximity labeling to provide the first systematic map of GP73 interactome in living cells. Our findings uncover a novel, unconventional function of GP73 as a regulator of cellular protein translation, likely mediated through its interaction with the eIF3 complex. This discovery significantly broadens our understanding of the biological roles of GP73 beyond its traditional function in the Golgi apparatus and suggests that it may act as a bridge between Golgi-related trafficking and the protein synthesis machinery. Furthermore, the technical framework established in this study provides a valuable template for investigating other complex organelle-associated protein networks and resolving transient macromolecular interactions in various physiological and pathological contexts.
2.Current Research Status,Challenges,Differentiation and Treatment Strategies of Traditional Chinese Medicine for Gastroesophageal Reflux Disease
Fengyun WANG ; Mi LYU ; Bingduo ZHOU ; Beihua ZHANG ; Yi WANG ; Tingting XU ; Cong HE ; Xiaokang WANG ; Xin LIU ; Yang WANG ; Kaiyue HUANG ; Lusi XU ; Xudong TANG
Journal of Traditional Chinese Medicine 2026;67(4):392-396
This article systematically reviews the current research status as well as diagnosis and treatment strategies of traditional Chinese medicine (TCM) for gastroesophageal reflux disease (GERD). Studies demonstrate that TCM, based on the "disease-syndrome combination" approach, exhibits multi-target advantages in alleviating symptoms of various GERD subtypes, promoting mucosal repair, regulating emotions, and facilitating the reduction of western medication. To address clinical challenges such as symptom overlap and limited therapeutic efficacy, strategies have been proposed including "treating different diseases with the same method" and integrated regulation based on viscera correlation. Future efforts should focus on elucidating the mechanisms of compound prescriptions, promoting TCM drug development under the "three-combination" evaluation framework that integrates TCM theory, human experience and clinical trial evidence, and optimizing integrated traditional and western medicine models to enhance GERD management.
3.Construction of Saikosaponin D Multifunctional Liposomes and Evaluation of Its Anti-liver Cancer Efficacy and Targeting
Kun YU ; Guochun YANG ; Yaliang JIANG ; Yunting XIAO ; Congxian WANG ; Qionge SUN ; Ziyue LI ; Yikun SHANG ; Yu MAO ; Xin CHENG
Chinese Journal of Experimental Traditional Medical Formulae 2026;32(9):205-216
ObjectiveTo construct a multifunctional liposomal delivery system by replacing cholesterol(Chol) in conventional liposomes with saikosaponin D(SSD) and modifying with poloxamer 407(P407) for co-delivery of curcumin(Cur). The system was evaluated for in vivo tumor targeting and inhibitory effects on mouse subcutaneous solid tumors. MethodsSingle-factor and orthogonal tests combined with information entropy weighting were used to optimize the formulation process of the liposome with encapsulation efficiency and absolute Zeta potential as indexes, and validation studies and liposomal characterization were performed. A subcutaneous solid tumor model was established by injecting H22 hepatocellular carcinoma cells subcutaneously into the dorsal surface of the right forelimb of mice. DiR-loaded traditional Chol liposomes(P407-DiR-Chol-LPs, PDCL) and novel SSD-based liposomes(P407-DiR-SSD-LPs, PDSL) were prepared by the optimized formulation process, and tail vein injection was performed to investigate the impact of SSD on liposome tumor targeting with small animal in vivo imaging. Mice were randomly divided into eight groups, including blank group, model group, free doxorubicin(DOX) group(2 mg·kg-1), free Cur group(8 mg·kg-1), free SSD group(10 mg·kg-1), P407-Cur-Chol-LPs(PCCL) group, P407-SSD-LPs(PSL) group, and P407-Cur-SSD-Lps(PCSL) group. Treatments were administered intraperitoneally every other day for seven doses. Antitumor efficacy and biocompatibility were evaluated by monitoring body weight change, organ indices, tumor volume and mass, relative tumor proliferation rate(T/C), and tumor growth inhibition rate(TGI). Histopathological analysis of liver, kidney, and tumor tissues was performed using hematoxylin-eosin(HE) staining. Serum levels of aspartate aminotransferase(AST), alanine aminotransferase (ALT), blood urea nitrogen(BUN), and creatinine(Crea)in mice were quantified by fully automated biochemical analyzer. ResultsOrthogonal test yielded optimal ratios of Cur, SSD, and P407 to soybean phosphatidylcholine(SPC) as 1∶25, 1∶20, and 1∶4. The optimized PCSL exhibited spherical morphology with a particle size of 179.15 nm, a Zeta potential of -47.25 mV, and an encapsulation efficiency of 96.40%. Its in vitro release profile conformed to first-order kinetics, demonstrating excellent storage stability and hemocompatibility. In vivo imaging revealed that the fluorescence signal in tumor tissues and the fluorescence intensity ratio between tumors and organs were significantly higher in the PDSL group than in the PDCL group(P<0.05, P<0.01). Among the treatment groups, PCSL group showed superior efficacy over free Cur group, free SSD group, PCCL group, and PSL group, with TGI>40% and T/C<60%, indicating pronounced anti-hepatocellular carcinoma effects(P<0.05, P<0.01). Histopathology and serum biochemistry indicated minimal hepatorenal toxicity and improved hepatic and renal function in PCSL-treated mice. ConclusionReplacing Chol with SSD in preparing multifunctional drug delivery systems not only stabilizes liposomes but also yields superior anti-hepatocellular carcinoma efficacy, achieving the effect of drug-excipient integration. Co-delivery of Cur via this system can be used for treating subcutaneous solid tumors in hepatocellular carcinoma, providing new insights and technical approaches for anti-hepatocellular carcinoma research and the meridian-guiding and messenger-directing theory in traditional Chinese medicine.
4.Interventional effects of function-rehabilitation-oriented physical training on the physical health of higher vocational college students
Chinese Journal of School Health 2026;47(8):1106-1111
Objective:
To investigate the intervention effects and mechanisms of function-rehabilitation-oriented physical training on the physical health of higher vocational college students, so as to provide replicable strategies for integrating physical education with health education in such institutions.
Methods:
In March 2024, a cluster random sampling method was employed to select 312 first and second year non sports major students from Chongqing Water Resources and Electric Engineering College as research subjects, and the selected classes were randomly divided into an intervention group ( n =151) and a control group ( n =161) by using a random number table. Both groups received a 16 week intervention program consisting of 2 academic hours per week from Macrh to July 2024. The control group followed the standard teaching curriculum for public physical education courses in higher vocational education, while the intervention group incorporated a function-rehabilitation-oriented physical training module into the regular physical education curriculum. For the module, stratified functional correction was implemented based on pre class functional movement screening results, with dedicated 10-15 minute intervention sessions per lesson accompanied by personalized exercise prescriptions delivered three times weekly. Before and after the intervention, Functional Movement Screen, the Exercise Attitude Scale, and the National Student Physical Health Standards (2014 Revision) were used for pre and post intervention assessments. Main effect of the intervention was examined via repeated measures analysis of variance, while chain mediating effect was analyzed by using the Hayes Process macro program.
Results:
After the intervention, the scores for functional movement quality (15.82±2.35), physical exercise attitude (237.64±17.22), and physical health level (76.45±7.82) in the intervention group were significantly higher than those before intervention (13.10±2.41, 199.51±15.78, 70.30±8.34) and those in the control group during the same period (13.08±2.81, 199.02±18.67, 71.42±7.56)( t =10.07, 20.34, 6.58; 9.21, 19.17, 5.57, all P < 0.01 ). Function-rehabilitation-oriented physical training directly and positively predicted physical health status ( β =0.18). Functional movement quality (effect size=0.21) and physical exercise attitude (effect size= 0.15 ) each served as independent mediators, their chain mediating effect was statistically significant (effect size=0.10)(all P < 0.01 ), with the total indirect effect accounting for 71.88% of the overall effect.
Conclusion
Function-rehabilitation-oriented physical training significantly improves the physical health of vocational college students through both direct effects and chain pathways, making it suitable for widespread implementation in vocational education institutions.
5.Pathogenesis Reasoning Chain-of-thought Supervision for Large Language Models: Syndrome Manifestation Recognition and Multidimensional Evaluation in Spleen-stomach Disorders
Shu-Han YANG ; Yu-Xin HU ; Xin-Yu YU ; Yu-Ying TU ; Yi-Chang ZANG ; Pan-Fei LI
Progress in Biochemistry and Biophysics 2026;53(5):1240-1263
ObjectiveThe essence of syndrome manifestation recognition in traditional Chinese medicine (TCM) is to infer the body’s latent pathogenesis state from clinical observational information, rather than to perform simple label matching. However, previous studies have largely modeled this task as syndrome pattern classification within a fixed label space, which does not adequately reflect the cognition process of TCM syndrome differentiation centered on pathogenesis reasoning, and is also insufficient to capture the openness, semantic variability, and cross-disease reusability of syndrome manifestation expression. This study aimed to investigate whether introducing pathogenesis reasoning chain-of-thought (PR-CoT) supervision into large language models (LLMs) could improve the quality and cognitive consistency of syndrome manifestation recognition and support cross-disease transfer. MethodsSyndrome manifestation recognition was formulated as a conditional generation task under the framework of clinical observational information (X)→pathogenesis structure (Z)→syndrome pattern output (Y), where Z serves as an explicit intermediate structural variable linking the clinical evidence and syndrome judgment. Within this framework, a PR-CoT-supervised dataset for syndrome manifestation recognition was constructed based on medical case records of spleen-stomach disorders. After preprocessing, information extraction, manual proofreading, and data cleaning, the dataset comprised 4 800 training cases, 400 development cases, and 400 test cases. Each sample was annotated with a structured PR-CoT consisting of three progressive levels: clinical information summarization, comprehensive pathogenesis analysis, and syndrome pattern output. Supervised fine-tuning was conducted on open-source LLMs, with an end-to-end model serving as the baseline. Qwen3-32B was used as the primary experimental model, and Qwen3-14B as the scale comparison model. A progressive multidimensional evaluation framework was further established, comprising a structural parsing level, a semantic similarity level, and an expert blind review level. At the structural parsing level, syndrome pattern expressions were decomposed into structural elements and evaluated using Precision, Recall, F1 score, and Jaccard similarity. At the semantic similarity level, independent LLMs scored the theoretical proximity between predicted and reference syndrome patterns. At the expert blind review level, three TCM experts independently evaluated model outputs on two dimensions: syndrome differentiation consistency and terminology standardization of syndrome patterns. In addition, zero-shot cross-disease transfer evaluation was conducted on gynecological and heart-system disorder test sets. ResultsAt the structural parsing level, PR-CoT supervision did not lead to a stable improvement in the element-wise overlap of syndrome pattern structural components. Compared with the corresponding baselines, neither Qwen3-32B nor Qwen3-14B showed consistent advantages in structural matching metrics after the introduction of PR-CoT supervision. In contrast, at the semantic similarity level, PR-CoT supervision produced stable positive gains across different model scales and evaluation systems. The average semantic score of Qwen3-32B increased from 6.425 8 in the baseline model to 6.585 0 after PR-CoT supervision, and that of Qwen3-14B increased from 5.870 0 to 5.964 2. At the expert blind review level, the overall score of Qwen3-32B (PR-CoT) was 7.026 0±0.107 7, higher than 6.416 3±0.288 9 for its baseline. In zero-shot cross-disease testing, the PR-CoT model still showed advantages in semantic evaluation and expert evaluation on both gynecological and heart-system disorder test sets, indicating a certain degree of transferability. ConclusionThe benefits of PR-CoT supervision are mainly reflected in TCM semantic consistency and clinical plausibility, rather than in improved hard matching of structural elements. These findings support understanding syndrome manifestation recognition as a process of generating and expressing latent pathogenesis structures, rather than as a classification task within a traditional fixed label space. By introducing pathogenesis reasoning as an explicit intermediate structure into the modeling process and combining it with a progressive multidimensional evaluation framework, this study provides a methodological pathway for intelligent TCM syndrome differentiation that integrates theoretical alignment, interpretability, and multi-level evaluation.
6.Pathogenesis Reasoning Chain-of-thought Supervision for Large Language Models: Syndrome Manifestation Recognition and Multidimensional Evaluation in Spleen-stomach Disorders
Shu-Han YANG ; Yu-Xin HU ; Xin-Yu YU ; Yu-Ying TU ; Yi-Chang ZANG ; Pan-Fei LI
Progress in Biochemistry and Biophysics 2026;53(5):1240-1263
ObjectiveThe essence of syndrome manifestation recognition in traditional Chinese medicine (TCM) is to infer the body’s latent pathogenesis state from clinical observational information, rather than to perform simple label matching. However, previous studies have largely modeled this task as syndrome pattern classification within a fixed label space, which does not adequately reflect the cognition process of TCM syndrome differentiation centered on pathogenesis reasoning, and is also insufficient to capture the openness, semantic variability, and cross-disease reusability of syndrome manifestation expression. This study aimed to investigate whether introducing pathogenesis reasoning chain-of-thought (PR-CoT) supervision into large language models (LLMs) could improve the quality and cognitive consistency of syndrome manifestation recognition and support cross-disease transfer. MethodsSyndrome manifestation recognition was formulated as a conditional generation task under the framework of clinical observational information (X)→pathogenesis structure (Z)→syndrome pattern output (Y), where Z serves as an explicit intermediate structural variable linking the clinical evidence and syndrome judgment. Within this framework, a PR-CoT-supervised dataset for syndrome manifestation recognition was constructed based on medical case records of spleen-stomach disorders. After preprocessing, information extraction, manual proofreading, and data cleaning, the dataset comprised 4 800 training cases, 400 development cases, and 400 test cases. Each sample was annotated with a structured PR-CoT consisting of three progressive levels: clinical information summarization, comprehensive pathogenesis analysis, and syndrome pattern output. Supervised fine-tuning was conducted on open-source LLMs, with an end-to-end model serving as the baseline. Qwen3-32B was used as the primary experimental model, and Qwen3-14B as the scale comparison model. A progressive multidimensional evaluation framework was further established, comprising a structural parsing level, a semantic similarity level, and an expert blind review level. At the structural parsing level, syndrome pattern expressions were decomposed into structural elements and evaluated using Precision, Recall, F1 score, and Jaccard similarity. At the semantic similarity level, independent LLMs scored the theoretical proximity between predicted and reference syndrome patterns. At the expert blind review level, three TCM experts independently evaluated model outputs on two dimensions: syndrome differentiation consistency and terminology standardization of syndrome patterns. In addition, zero-shot cross-disease transfer evaluation was conducted on gynecological and heart-system disorder test sets. ResultsAt the structural parsing level, PR-CoT supervision did not lead to a stable improvement in the element-wise overlap of syndrome pattern structural components. Compared with the corresponding baselines, neither Qwen3-32B nor Qwen3-14B showed consistent advantages in structural matching metrics after the introduction of PR-CoT supervision. In contrast, at the semantic similarity level, PR-CoT supervision produced stable positive gains across different model scales and evaluation systems. The average semantic score of Qwen3-32B increased from 6.425 8 in the baseline model to 6.585 0 after PR-CoT supervision, and that of Qwen3-14B increased from 5.870 0 to 5.964 2. At the expert blind review level, the overall score of Qwen3-32B (PR-CoT) was 7.026 0±0.107 7, higher than 6.416 3±0.288 9 for its baseline. In zero-shot cross-disease testing, the PR-CoT model still showed advantages in semantic evaluation and expert evaluation on both gynecological and heart-system disorder test sets, indicating a certain degree of transferability. ConclusionThe benefits of PR-CoT supervision are mainly reflected in TCM semantic consistency and clinical plausibility, rather than in improved hard matching of structural elements. These findings support understanding syndrome manifestation recognition as a process of generating and expressing latent pathogenesis structures, rather than as a classification task within a traditional fixed label space. By introducing pathogenesis reasoning as an explicit intermediate structure into the modeling process and combining it with a progressive multidimensional evaluation framework, this study provides a methodological pathway for intelligent TCM syndrome differentiation that integrates theoretical alignment, interpretability, and multi-level evaluation.
7.Epidemiological characteristics of imported dengue fever cases in Fengtai District, Beijing, from 2007 to 2025
Yan MENG ; Yang YANG ; Xiao-xing YANG ; Jun-yong YANG ; Ruo-yi DU ; Li-na TIAN ; Ruo-xi LI ; Gui-yin LIN ; Xiao-li RUAN ; Jian-jun ZHANG ; Zhen-jiang XIN ; Li-li TIAN
Acta Parasitologica et Medica Entomologica Sinica 2026;33(3):180-186
Objective We reviewed and analyzed the epidemiological data of 83 imported dengue fever cases reported in Fengtai District, Beijing, from 2007 to 2025, to delineate their epidemiological characteristics and guide the dengue fever prevention and control strategy in the future. Methods Data on dengue fever cases in Fengtai District from 2007 to 2025 were collected to identify the epidemic factors and characteristics using descriptive epidemiological method. Results All 83 dengue fever cases reported in this region over the past two decades have been imported from abroad or other domestic areas, with Southeast Asian countries being identified as the primary source of imported infections, accounting for 42 cases (50.60%), followed by 15 cases (18.07%) from Chinese provinces other than Beijing. The remaining import sources included 13 cases from South Asia,8 from African countries, and each from Oceania, South America, and Europe. Disease onset was found concentrated between May and November. The sex ratio (male-to-female) is 1.59:1. The age of onset ranged from 14 to 61 years old, with a median age of 36. The largest proportion of cases was observed among cadres and office workers (31 cases, 37.35%), followed by businessmen (13 cases, 15.67%), and householders or the unemployed (10 cases,12.05%). Travel visit was identified as the primary reason for their exposure history. Conclusions All dengue fever cases reported in Fengtai from 2007 to 2025 were imported, with an increasing trend of imported cases in Beijing originating from other Chinese provinces. It is essential to strengthen health education for foreign travelers and returning residents, enhance clinical diagnosis and treatment training for medical personnel, eliminate mosquito breeding sites, and reduce mosquito density through active patriotic health campaigns.
8.Association between cannabis use and risk of gynecomastia: commentary on "Gynecomastia in adolescent males: current understanding of its etiology, pathophysiology, diagnosis, and treatment"
Jia-Lin WU ; Jun-Yang LUO ; Xin-Yi DENG ; Zai-Bo JIANG
Annals of Pediatric Endocrinology & Metabolism 2025;30(1):52-53
9.Chemical constituents from Tetrastigma hemsleyanum and their antitumor activity in vitro
Yi LONG ; Li-zhi ZHANG ; Piao-piao JIANG ; Nan KUANG ; Xin-yu ZHANG ; Yu-pei YANG ; Bin LI ; Wei WANG
Chinese Traditional Patent Medicine 2025;47(9):2932-2941
AIM To study the chemical constituents from Tetrastigma hemsleyanum Diels et Gilg and their antitumor activity in vitro.METHODS Silica gel,ODS,Sephadex LH-20 and semi-preparative HPLC were used for isolation and purification,then the structures of obtained compounds were identified by physicochemical properties and spectral data.The antitumor activity in vitro was determined by MTT mothod.RESULTS Twenty-eight compounds were isolated and identified as triphyllin A(1),eruberin B(2),(2S,4R)-5,7-dihydroxy-4,4'-dimethyl-6,8-dimethyl-flavan-5-O-β-D-6-acetylglucopyranoside-7-O-β-D-glucopyranoside(3),eruberin A(4),abacopterin Ⅰ(5),matteucinol(6),homoerodictyol(7),(2S)-5,3',4'-trihydroxy-7-methoxy-flavanone(8),(2S)-5,2',5'-trihydroxy-7-methoxyflavanone(9),galinsonside B(10),quercetin-3-O-β-D-glucopyranoside(11),kaempferol 3-O-robinobioside(12),rutin(13),geniposide(14),jasminoside A(15),β-sitostenone(16),sitosterol palmitate(17),β-sitosterol(18),ursolic acid(19),hyptadienic acid(20),3,4-dihydroxybenzoic acid(21),3,4-dimethoxybenzoic acid(22),gallic acid(23),dibutylphthalate(24),bis-(2-ethylhexyl)phthalate(25),9-nonadecenoic acid(26),triacylglycerol(27),crocin Ⅰ(28).The IC50 values of compound 1 for human gastric adenocarcinoma cells BGC-823 and human colon cancer cells HCT-116 were(22.07±0.38),(20.67±0.11)μmol/L,respectively.The IC50 value of compound 9 for BGC-823 cells was(21.58±0.05)μmol/L,and the IC50 value of compound 4 for HCT-116 cells was(16.67±0.36)μmol/L.CONCLUSION Compounds 1-10,14-15 and 28 are first isolated from Tetrastigma genus.Compounds 1,4,9 have weak antitumor activity in vitro.
10.Determination of 238Pu,239Pu,240Pu and 241Pu in Soil by Tandem Quadrupole Inductively Coupled Plasmon-Mass Spectrometry
Yi-Chao GUO ; Chen-Yang PENG ; Xin-Yu DU ; Feng ZHANG ; Hao-Lin ZHOU ; Ke-Liang SHI ; Shan XING ; Xiao-Lin HOU
Chinese Journal of Analytical Chemistry 2025;53(3):397-406
Plutonium isotopes(238Pu,239Pu,240Pu and 241Pu)in the environment are important"fingerprint"nuclides in the study of nuclear activity traceability.The content of plutonium isotopes in the environmental metrics is usually very low,and the measurement of these isotopes,especially 238Pu,using mass spectrometry is seriously interfered with by the coexisting 238U.The analysis of several plutonium isotopes in soil usually requires combination of multiple measurement techniques,which leads to a long analysis time and large uncertainty in the isotope ratio.In this work,the hydrous titanium oxide(HTiO)precipitated by the hydrolysis of titanium oxydichloride(TiOCl2)under near-neutral condition was used to preconcentrate plutonium from the soil digestion solution,and the highly efficient decontamination of 238U in the sample was achieved by TK200 resin column chromatography with a decontamination factor of 108.Simulation resuts of density functional theory(DFT)showed that NH3 was considered as a promising reaction gas to eliminate the interference of 238U from 238Pu measurement using mass spectrometry due to the significant discrepancy of the chemical reactivity of U+and Pu+with the reactive gas NH3.Experiments confirmed that by optimizing the flow rates of collision gas(He)and reaction gas(NH3),the interference of 238U could be effectively suppressed,and the decontamination factor of 238U was 104.Combined with chemical separation,the overall decontamination factor of 238U could reach 1012 by using the developed method.By combining chemical separation and tandem quadrupole inductively coupled plasmon-mass spectrometry(ICP-MS/MS)measurement,the simultaneous determination of four ultra-trace plutonium isotopes in soil was realized,and the detection limit of plutonium isotopes was at the femtogram level.Analysis of the international standard reference materials(NIST-SRM-4357 and IAEA-384)showed that the established method could be successfully used for the accurate analysis of ultra-trace four plutonium isotopes(238Pu,239Pu,240Pu and 241Pu)in soil samples.


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