应用ICP-MS、AFS、GF-AAS测定食品中As、Cd、Hg、Pb方法的对比研究

应用ICP-MS法测定食品中的As、Cd、Hg、Pb,AFS法测定As、Hg,GF-AAS法测定Cd、Pb,并对3种测定方法进行对比研究。采用微波消解法作为ICP-MS法的样品前处理方法,湿式消解法作为AFS、GF-AAS法的前处理方法。通过优化消解条件,优化ICP-MS、AFS及GF-AAS仪器测定工作条件,选择适宜内标元素、EPA200.8标准干扰校正方程、硫脲-抗坏血酸掩蔽剂、硝酸镁-硝酸钯混合基体改进剂等办法,利用小麦粉(GBW08503b)和大米粉(GBW10010)国家标准物质验证各方法的准确度与可靠性。测定值均在标准值允许范围内,食品试样比对测定结果相对偏差均小于20%。ICP-MS法线性动态范围宽,不必稀释样品,适合批量样品多元素同时分析,但仪器昂贵、实验成本相对较高;AFS、GF-AAS法是单一元素分析,保证了测定结果准确、可靠,但由于线性范围窄,部分样品需要稀释,分析周期较长。

ICP-MS法和GF-AAS法测定饲料级腐植酸钠中铅、镉、铬含量的比较研究

为了测定饲料级腐植酸钠中铅、镉、铬三种重金属元素的含量,试验采用全自动石墨消解仪消解腐植酸钠样品后,再分别用电感耦合等离子体质谱(ICP-MS)法和国家标准方法——石墨炉原子吸收光谱(GF-AAS)法测定,同时对这两种方法进行了比较分析。结果表明:ICP-MS法和GF-AAS法均能对饲料级腐植酸钠中铅、镉、铬三种重金属元素进行很好的分析检测,各元素校正曲线的相关系数均能达到或超过0.9987,线性关系良好;各元素检出限均等于或小于0.0062 mg/kg,灵敏度较高;加标回收率范围在90.1%~104.7%之间,回收率良好;相对标准偏差(RSD)均小于5.00%,精密度高;质控样品测定值的平均值均在标示值范围内,准确性良好。针对铅、镉、铬三种元素的检测,与GF-AAS法相比,ICP-MS法检出限更低,灵敏度更高,加标回收率表现更优,精密度和稳定性更佳。说明ICP-MS法和GF-AAS法均可用于对饲料级腐植酸钠样品中铅、镉、铬三种重金属元素进行分析检测;ICP-MS法具有更低的检出限,更高的灵敏度和更优的加标回收率和精密度,且一次进样可以同时得到多种元素的检测结果,简便快捷,更能满足生产中大批量快速检测的需求。

石墨炉原子吸收光谱法(GF-AAS)测定食品添加剂二氧化钛中重金属铅的研究

本文用石墨炉原子吸收光谱法测定了食品添加剂二氧化钛中重金属铅的含量。在0 80ng/mL的线性范围内,其相关系数R2为0.996,回收率在100.9%111.7%,相对标准偏差为4.0%,检出限与定量限分别为0.68ng/mL和2.3ng/mL。该方法稳定、可靠,适合于食品添加剂二氧化钛中重金属铅的测定。

泡塑吸附-GF-AAS和ICP–MS法测定化探金的对比研究

王水溶样-泡塑吸附富集-硫脲解脱,较GF-AAS,ICP-MS测试化探金样品具有高灵敏度、低检出限和宽线性,结果精密度好,准确度高。

GF-AAS 法测定食品及饮料中微量锗

目前，普遍认为微量有机锗有增强人体免疫作用，因此，建立准确、快速测定食品及饮料中微量锗的方法就显得十分必要，但在这方面的文献报导较少。有的方法也具有一定的局限性，例如：直接石墨炉原子吸收法灵敏度低，干扰严重，且在石墨炉中锗易形成不同价态氧化物及高挥发...

GF-AAS与ICP-MS测定化探样品中金的含量

用塑料瓶溶矿0.5%硫脲提取,对同一标准样品中金含量分别采用GF-AAS和ICP-MS进行了分析,对这两种仪器在测定金时的检出限和检出上限、测试时间、测试成本进行分析。试验结果表明ICP-MS的检出限与GF-AAS基本一样,检出上限、测试时间、测试成本ICP-MS都优于GF-AAS。

ICP-MS、AFS、GF-AAS对食品中As、Cd、Hg、Pb的检查对比分析

利用ICP-MS、AFS、GF-AAS对食品中的As、Cd、Hg、Pb进行测定,通过优化消解条件选择合适的内标元素、标准干扰校正方程及化学物质混合基体改进剂,利用小麦粉或者是大麦粉等来验证各种方法的准确度和检测的可靠性。

GF-AAS与ICP-MS测定水中总铬含量的方法比对及其不确定度评定

石墨炉原子吸收光谱(GF-AAS)法和电感耦合等离子体质谱(ICP-MS)法是灵敏度较高的2种测定水中铬含量的方法。文中采用357.9 nm与429.0 nm波长条件下GF-AAS法、52与53质核比条件下ICP-MS法测定水质铬标准物质中总铬元素含量,从标准曲线、准确性、重复性、加标回收率、检出限、定量限、测量不确定度评定多个方面进行对比分析。结果表明,4组测定条件下,标准物质测定结果均在标准值不确定度范围内。其中,429.0 nm波长GF-AAS法测定结果相对其他3组显著偏低(P<0.05);ICP-MS法在检出限、定量限方面优于GF-AAS法;GF-AAS法测定结果357.9 nm波长优于429.0 nm波长。

A Review on Sources,Extractions and Analysis Methods of a Sustainable Biomaterial:Tannins

Condensed and hydrolysable tannins are non-toxic natural polyphenols that are a commercial commodity industrialized for tanning hides to obtain leather and for a growing number of other industrial applications mainly to substitute petroleum-based products.They are a definite class of sustainable materials of the forestry industry.They have been in operation for hundreds of years to manufacture leather and now for a growing number of applications in a variety of other industries,such as wood adhesives,metal coating,pharmaceutical/medical applications and several others.This review presents the main sources,either already or potentially commercial of this forestry by-materials,their industrial and laboratory extraction systems,their systems of analysis with their advantages and drawbacks,be these methods so simple to even appear primitive but nonetheless of proven effectiveness,or very modern and instrumental.It constitutes a basic but essential summary of what is necessary to know of these sustainable materials.In doing so,the review highlights some of the main challenges that remain to be addressed to deliver the quality and economics of tannin supply necessary to fulfill the industrial production requirements for some materials-based uses.

Drilling-based measuring method for the c-φ parameter of rock and its field application

The technology of drilling tests makes it possible to obtain the strength parameter of rock accurately in situ. In this paper, a new rock cutting analysis model that considers the influence of the rock crushing zone(RCZ) is built. The formula for an ultimate cutting force is established based on the limit equilibrium principle. The relationship between digital drilling parameters(DDP) and the c-φ parameter(DDP-cφ formula, where c refers to the cohesion and φ refers to the internal friction angle) is derived, and the response of drilling parameters and cutting ratio to the strength parameters is analyzed. The drillingbased measuring method for the c-φ parameter of rock is constructed. The laboratory verification test is then completed, and the difference in results between the drilling test and the compression test is less than 6%. On this basis, in-situ rock drilling tests in a traffic tunnel and a coal mine roadway are carried out, and the strength parameters of the surrounding rock are effectively tested. The average difference ratio of the results is less than 11%, which verifies the effectiveness of the proposed method for obtaining the strength parameters based on digital drilling. This study provides methodological support for field testing of rock strength parameters.

A comparison study on structure-function relationship of polysaccharides obtained from sea buckthorn berries using different methods:antioxidant and bile acid-binding capacity

In this study,the structural characters,antioxidant activities and bile acid-binding ability of sea buckthorn polysaccharides(HRPs)obtained by the commonly used hot water(HRP-W),pressurized hot water(HRP-H),ultrasonic(HRP-U),acid(HRP-C)and alkali(HRP-A)assisted extraction methods were investigated.The results demonstrated that extraction methods had significant effects on extraction yield,monosaccharide composition,molecular weight,particle size,triple-helical structure,and surface morphology of HRPs except for the major linkage bands.Thermogravimetric analysis showed that HRP-U with filamentous reticular microstructure exhibited better thermal stability.The HRP-A with the lowest molecular weight and highest arabinose content possessed the best antioxidant activities.Moreover,the rheological analysis indicated that HRPs with higher galacturonic acid content and molecular weight showed higher viscosity and stronger crosslinking network(HRP-C,HRP-W and HRP-U),which exhibited stronger bile acid binding capacity.The present findings provide scientific evidence in the preparation technology of sea buckthorn polysaccharides with good antioxidant and bile acid binding capacity which are related to the structure affected by the extraction methods.

Material point method simulation of hydro-mechanical behaviour in twophase porous geomaterials: A state-of-the-art review

The material point method(MPM)has been gaining increasing popularity as an appropriate approach to the solution of coupled hydro-mechanical problems involving large deformation.In this paper,we survey the current state-of-the-art in the MPM simulation of hydro-mechanical behaviour in two-phase porous geomaterials.The review covers the recent advances and developments in the MPM and their extensions to capture the coupled hydro-mechanical problems involving large deformations.The focus of this review is aiming at providing a clear picture of what has or has not been developed or implemented for simulating two-phase coupled large deformation problems,which will provide some direct reference for both practitioners and researchers.

Deciphering gastric inflammation-induced tumorigenesis through multi-omics data and AI methods

Gastric cancer(GC), the fifth most common cancer globally, remains the leading cause of cancer deaths worldwide. Inflammation-induced tumorigenesis is the predominant process in GC development;therefore, systematic research in this area should improve understanding of the biological mechanisms that initiate GC development and promote cancer hallmarks. Here, we summarize biological knowledge regarding gastric inflammation-induced tumorigenesis, and characterize the multi-omics data and systems biology methods for investigating GC development. Of note, we highlight pioneering studies in multi-omics data and state-of-the-art network-based algorithms used for dissecting the features of gastric inflammation-induced tumorigenesis, and we propose translational applications in early GC warning biomarkers and precise treatment strategies. This review offers integrative insights for GC research, with the goal of paving the way to novel paradigms for GC precision oncology and prevention.

GF-AAS法测定黄精中铬含量的方法研究

本文采用微波消解法对黄精样品进行前处理,利用石墨炉-原子吸收法(Graphite Furnace Atomic Absorption Spectrometry,GF-AAS)测定黄精中铬的含量。结果表明,当铬含量在0~10.0μg·L^(-1)线性关系较好,线性方程相关系数为0.9990,检出限为0.009 mg·kg^(-1),定量限为0.028 mg·kg^(-1),精密度、重复性试验(n=6)的RSD值≤2.50%,加标回收率(n=6)为96.2%~102.4%(RSD=2.49%)。该方法检出限低、易操作、结果准确,可用于黄精中重金属铬含量的测定。

Volumetric lattice Boltzmann method for pore-scale mass diffusionadvection process in geopolymer porous structures

Porous materials present significant advantages for absorbing radioactive isotopes in nuclear waste streams.To improve absorption efficiency in nuclear waste treatment,a thorough understanding of the diffusion-advection process within porous structures is essential for material design.In this study,we present advancements in the volumetric lattice Boltzmann method(VLBM)for modeling and simulating pore-scale diffusion-advection of radioactive isotopes within geopolymer porous structures.These structures are created using the phase field method(PFM)to precisely control pore architectures.In our VLBM approach,we introduce a concentration field of an isotope seamlessly coupled with the velocity field and solve it by the time evolution of its particle population function.To address the computational intensity inherent in the coupled lattice Boltzmann equations for velocity and concentration fields,we implement graphics processing unit(GPU)parallelization.Validation of the developed model involves examining the flow and diffusion fields in porous structures.Remarkably,good agreement is observed for both the velocity field from VLBM and multiphysics object-oriented simulation environment(MOOSE),and the concentration field from VLBM and the finite difference method(FDM).Furthermore,we investigate the effects of background flow,species diffusivity,and porosity on the diffusion-advection behavior by varying the background flow velocity,diffusion coefficient,and pore volume fraction,respectively.Notably,all three parameters exert an influence on the diffusion-advection process.Increased background flow and diffusivity markedly accelerate the process due to increased advection intensity and enhanced diffusion capability,respectively.Conversely,increasing the porosity has a less significant effect,causing a slight slowdown of the diffusion-advection process due to the expanded pore volume.This comprehensive parametric study provides valuable insights into the kinetics of isotope uptake in porous structures,facilitating the development of porous materials for nuclear waste treatment applications.

Uncertainties of landslide susceptibility prediction: Influences of random errors in landslide conditioning factors and errors reduction by low pass filter method

In the existing landslide susceptibility prediction(LSP)models,the influences of random errors in landslide conditioning factors on LSP are not considered,instead the original conditioning factors are directly taken as the model inputs,which brings uncertainties to LSP results.This study aims to reveal the influence rules of the different proportional random errors in conditioning factors on the LSP un-certainties,and further explore a method which can effectively reduce the random errors in conditioning factors.The original conditioning factors are firstly used to construct original factors-based LSP models,and then different random errors of 5%,10%,15% and 20%are added to these original factors for con-structing relevant errors-based LSP models.Secondly,low-pass filter-based LSP models are constructed by eliminating the random errors using low-pass filter method.Thirdly,the Ruijin County of China with 370 landslides and 16 conditioning factors are used as study case.Three typical machine learning models,i.e.multilayer perceptron(MLP),support vector machine(SVM)and random forest(RF),are selected as LSP models.Finally,the LSP uncertainties are discussed and results show that:(1)The low-pass filter can effectively reduce the random errors in conditioning factors to decrease the LSP uncertainties.(2)With the proportions of random errors increasing from 5%to 20%,the LSP uncertainty increases continuously.(3)The original factors-based models are feasible for LSP in the absence of more accurate conditioning factors.(4)The influence degrees of two uncertainty issues,machine learning models and different proportions of random errors,on the LSP modeling are large and basically the same.(5)The Shapley values effectively explain the internal mechanism of machine learning model predicting landslide sus-ceptibility.In conclusion,greater proportion of random errors in conditioning factors results in higher LSP uncertainty,and low-pass filter can effectively reduce these random errors.

Sparse Modal Decomposition Method Addressing Underdetermined Vortex-Induced Vibration Reconstruction Problem for Marine Risers

When investigating the vortex-induced vibration(VIV)of marine risers,extrapolating the dynamic response on the entire length based on limited sensor measurements is a crucial step in both laboratory experiments and fatigue monitoring of real risers.The problem is conventionally solved using the modal decomposition method,based on the principle that the response can be approximated by a weighted sum of limited vibration modes.However,the method is not valid when the problem is underdetermined,i.e.,the number of unknown mode weights is more than the number of known measurements.This study proposed a sparse modal decomposition method based on the compressed sensing theory and the Compressive Sampling Matching Pursuit(Co Sa MP)algorithm,exploiting the sparsity of VIV in the modal space.In the validation study based on high-order VIV experiment data,the proposed method successfully reconstructed the response using only seven acceleration measurements when the conventional methods failed.A primary advantage of the proposed method is that it offers a completely data-driven approach for the underdetermined VIV reconstruction problem,which is more favorable than existing model-dependent solutions for many practical applications such as riser structural health monitoring.

Numerical manifold method for thermo-mechanical coupling simulation of fractured rock mass

As a calculation method based on the Galerkin variation,the numerical manifold method(NMM)adopts a double covering system,which can easily deal with discontinuous deformation problems and has a high calculation accuracy.Aiming at the thermo-mechanical(TM)coupling problem of fractured rock masses,this study uses the NMM to simulate the processes of crack initiation and propagation in a rock mass under the influence of temperature field,deduces related system equations,and proposes a penalty function method to deal with boundary conditions.Numerical examples are employed to confirm the effectiveness and high accuracy of this method.By the thermal stress analysis of a thick-walled cylinder(TWC),the simulation of cracking in the TWC under heating and cooling conditions,and the simulation of thermal cracking of the SwedishÄspöPillar Stability Experiment(APSE)rock column,the thermal stress,and TM coupling are obtained.The numerical simulation results are in good agreement with the test data and other numerical results,thus verifying the effectiveness of the NMM in dealing with thermal stress and crack propagation problems of fractured rock masses.

A stable implicit nodal integration-based particle finite element method(N-PFEM)for modelling saturated soil dynamics

In this study,we present a novel nodal integration-based particle finite element method(N-PFEM)designed for the dynamic analysis of saturated soils.Our approach incorporates the nodal integration technique into a generalised Hellinger-Reissner(HR)variational principle,creating an implicit PFEM formulation.To mitigate the volumetric locking issue in low-order elements,we employ a node-based strain smoothing technique.By discretising field variables at the centre of smoothing cells,we achieve nodal integration over cells,eliminating the need for sophisticated mapping operations after re-meshing in the PFEM.We express the discretised governing equations as a min-max optimisation problem,which is further reformulated as a standard second-order cone programming(SOCP)problem.Stresses,pore water pressure,and displacements are simultaneously determined using the advanced primal-dual interior point method.Consequently,our numerical model offers improved accuracy for stresses and pore water pressure compared to the displacement-based PFEM formulation.Numerical experiments demonstrate that the N-PFEM efficiently captures both transient and long-term hydro-mechanical behaviour of saturated soils with high accuracy,obviating the need for stabilisation or regularisation techniques commonly employed in other nodal integration-based PFEM approaches.This work holds significant implications for the development of robust and accurate numerical tools for studying saturated soil dynamics.

An inverse analysis of fluid flow through granular media using differentiable lattice Boltzmann method

This study presents a method for the inverse analysis of fluid flow problems.The focus is put on accurately determining boundary conditions and characterizing the physical properties of granular media,such as permeability,and fluid components,like viscosity.The primary aim is to deduce either constant pressure head or pressure profiles,given the known velocity field at a steady-state flow through a conduit containing obstacles,including walls,spheres,and grains.The lattice Boltzmann method(LBM)combined with automatic differentiation(AD)(AD-LBM)is employed,with the help of the GPU-capable Taichi programming language.A lightweight tape is used to generate gradients for the entire LBM simulation,enabling end-to-end backpropagation.Our AD-LBM approach accurately estimates the boundary conditions for complex flow paths in porous media,leading to observed steady-state velocity fields and deriving macro-scale permeability and fluid viscosity.The method demonstrates significant advantages in terms of prediction accuracy and computational efficiency,making it a powerful tool for solving inverse fluid flow problems in various applications.