Two-dimensional perovskite ferroelectric which strongly couple ferroelectricity with semiconducting properties are promising candidates for optoelectronic applications.However,it is still a great challenge to fabricat...Two-dimensional perovskite ferroelectric which strongly couple ferroelectricity with semiconducting properties are promising candidates for optoelectronic applications.However,it is still a great challenge to fabricate self-powered broadband photodetectors with low detection limit.Herein,we successfully realized self-powered broadband photodetection with low detection limit by using a trilayered perovskite ferroelectric(BA)_(2)EA_(2)Pb_(3)I_(10)(1,BA=n-butylamine,EA=ethylamine).Giving to its large spontaneous polarization(5.6μC/cm^(2)),1 exhibits an open-circuit voltage of 0.25 V which provide driving force to separate carriers.Combining with its low dark current(~10^(-14)A)and narrow bandgap(Eg=1.86 e V),1 demonstrates great potential on detecting the broadband weak lights.Thus,a prominent photodetection performance with high open-off ratio(~10^(5)),outstanding responsivity(>10 m A/W),and promising detectivity(>1011Jones),as well as the low detecting limit(~nW/cm^(2))among the wide wavelength from 377 nm to637 nm was realized based on the single crystal of 1.This work demonstrates the great potential of 2D perovskite ferroelectric on self-powered broadband photodetectors.展开更多
Traditional Pt/C electrode materials are prone to corrosion and detachment during H_(2)S detection,leading to a decrease in fuel cell-type sensor performance.Here,a high-performance H_(2)S sensor based on Pt loaded Ti...Traditional Pt/C electrode materials are prone to corrosion and detachment during H_(2)S detection,leading to a decrease in fuel cell-type sensor performance.Here,a high-performance H_(2)S sensor based on Pt loaded Ti_(3)C_(2)electrode material with-O/-OH terminal groups was designed and prepared.Experimental tests showed that the Pt/Ti_(3)C_(2)sensor has good sensitivity(0.162μA/ppm)and a very low detection limit to H_(2)S(10 ppb).After 90 days of stability testing,the response of the Pt/Ti_(3)C_(2)sensor shows a smaller decrease of 2%compared to that of the Pt/C sensor(22.9%).Meanwhile,the sensor also has high selectivity and repeatability.The density functional theory(DFT)calculation combined with the experiment results revealed that the improved H_(2)S sensing mechanism is attributed to the fact that the strong interaction between Pt and Ti_(3)C_(2)via the Pt-O-Ti bonding can reduce the formation energy of Pt and Ti_(3)C_(2),ultimately prolonging the sensor’s service life.Furthermore,the catalytic property of Pt can decrease the adsorption energy and dissociation barrier of H_(2)S on Pt/Ti_(3)C_(2)surface,greatly enhance the ability to generate protons and effectively transfer charges,realizing good sensitivity and high selectivity of the sensor.The sensor works at room temperature,making it very promising in the field of H_(2)S detection in future.展开更多
A special Fe3O4nanoparticles–graphene（Fe3O4–GN） composite as a magnetic label was employed for biodetection using giant magnetoresistance（GMR） sensors with a Wheatstone bridge. The Fe3O4–GN composite exhibits a...A special Fe3O4nanoparticles–graphene（Fe3O4–GN） composite as a magnetic label was employed for biodetection using giant magnetoresistance（GMR） sensors with a Wheatstone bridge. The Fe3O4–GN composite exhibits a strong ferromagnetic behavior with the saturation magnetization MS of approximately 48 emu/g, coercivity HC of 200 Oe, and remanence Mr of 8.3 emu/g, leading to a large magnetic fringing field. However, the Fe3O4 nanoparticles do not aggregate together, which can be attributed to the pinning and separating effects of graphene sheet to the magnetic particles. The Fe3O4–GN composite is especially suitable for biodetection as a promising magnetic label since it combines two advantages of large fringing field and no aggregation. As a result, the concentration x dependence of voltage difference ｜？V｜ between detecting and reference sensors undergoes the relationship of ｜？V｜ = 240.5 lgx ＋ 515.2 with an ultralow detection limit of 10 ng/mL（very close to the calculated limit of 7 ng/mL） and a wide detection range of 4 orders.展开更多
In this work,multivariate detection limits(MDL)estimator was obtained based on the microelectro-mechanical systems–near infrared(MEMS–NIR)technology coupled with two sampling accessories to assess the detection capa...In this work,multivariate detection limits(MDL)estimator was obtained based on the microelectro-mechanical systems–near infrared(MEMS–NIR)technology coupled with two sampling accessories to assess the detection capability of four quality parameters(glycyrrhizic acid,liquiritin,liquiritigenin and isoliquiritin)in licorice from di®erent geographical regions.112 licorice samples were divided into two parts(calibration set and prediction set)using Kennard–Stone(KS)method.Four quality parameters were measured using high-performance liquid chromatography(HPLC)method according to Chinese pharmacopoeia and previous studies.The MEMS–NIR spectra were acquired from¯ber optic probe(FOP)and integrating sphere,then the partial least squares(PLS)model was obtained using the optimum processing method.Chemometrics indicators have been utilized to assess the PLS model performance.Model assessment using chemometrics indicators is based on relative mean prediction error of all concentration levels,which indicated relatively low sensitivity for low-content analytes(below 1000 parts per million(ppm)).Therefore,MDL estimator was introduced with alpha error and beta error based on good prediction characteristic of low concentration levels.The result suggested that MEMS–NIR technology coupled with fiber optic probe(FOP)and integrating sphere was able to detect minor analytes.The result further demonstrated that integrating sphere mode(i.e.,MDL0:05;0:05,0.22%)was more robust than FOP mode(i.e.,MDL0:05;0:05,0.48%).In conclusion,this research proposed that MDL method was helpful to determine the detection capabilities of low-content analytes using MEMS–NIR technology and successful to compare two sampling accessories.展开更多
Based on fundamental arguments, the expressions for the decision limit and the detection limit both in the count domain and in the count rate domain are derived.These expressions are found to be different from those s...Based on fundamental arguments, the expressions for the decision limit and the detection limit both in the count domain and in the count rate domain are derived.These expressions are found to be different from those shown in the existing literature.展开更多
Lead-halide perovskite single crystal(SC)heterojunctions have attracted significant attention for X-raydetection owing to their unique combination of high sensitivity,resolution,stability and low detection limit.Howev...Lead-halide perovskite single crystal(SC)heterojunctions have attracted significant attention for X-raydetection owing to their unique combination of high sensitivity,resolution,stability and low detection limit.However,the toxicity of lead in those perovskite heterojunctions limitstheir practical applications.Herein,we report the constructionof the first all-inorganic lead-free Cs_(2)AgBiBr_(6)/Cs_(3)Bi_(2)Br_(9)SCheterojunctions with an area of 20×20 mm^(2)via a facile liquidphase epitaxial method through temperature-lowering crystallization.The epitaxial crystallization of the three-dimensional(3D)Cs_(2)AgBiBr_(6)SC film on a 2D Cs_(3)Bi_(2)Br_(9)SCsubstrate requires a large driving force for transitioning fromthe Volmer–Weber mode to the layer-by-layer growth modeunder a rapid cooling rate.The Cs_(2)AgBiBr_(6)/Cs_(3)Bi_(2)Br_(9)SCheterojunction detector achieves a high sensitivity of1390μC Gy_(air)^(−1)cm^(−2)for 100 keV hard X-ray detection atroom temperature,which is enhanced to 2075μC Gy_(air)^(−1)cm^(−2)at 75℃,demonstrating impressive high-temperature stability.Moreover,the detector achieves a detection limit of37.48 nG_(yair)s^(−1)and excellent stability for 90 days without anyencapsulation.This work demonstrates the feasibility of usingthe epitaxial mechanism of perovskite formation on a highsurface-energy substrate for the controllable construction of a3D/2D heterojunction that significantly enhances X-ray detection performance.展开更多
Recent studies suggest per-and polyfluoroalkyl substances(PFAS)are ubiquitous in rivers worldwide.In the Asia-Pacific region,the frequency of PFAS detection in rivers is increasing.However,the overwhelming majority of...Recent studies suggest per-and polyfluoroalkyl substances(PFAS)are ubiquitous in rivers worldwide.In the Asia-Pacific region,the frequency of PFAS detection in rivers is increasing.However,the overwhelming majority of studies and data represent high population and urbanized river catchments.In this study,we investigate PFAS occurrence in major Philippines river systems characterized by both high and low population densities.In the Pasig Laguna de Bay River,which drains a major urban conurbation,we detected PFAS at concentrations typical of global rivers.Unexpectedly,we did not detect PFAS in river water or sediments in low population density river catchments,despite our instrument detection limits being lower than the vast majority of river concentrations reported worldwide.We hypothesize that septic tanks,as the dominant wastewater treatment practice in Philippines catchments,may control the release of PFAS into groundwater and rivers in the Philippines.However,no groundwater PFAS data currently exist to validate this supposition.More broadly,our findings highlight the need for more representative PFAS sampling and analysis in rivers to more accurately represent regional and global detection frequencies and trends.展开更多
Polarized-light photodetectors are the indispensable elements for practical optical and optoelectronic device applications.Two-dimensional(2D)hybrid perovskite ferroelectrics,in which the coupling of spontaneous polar...Polarized-light photodetectors are the indispensable elements for practical optical and optoelectronic device applications.Two-dimensional(2D)hybrid perovskite ferroelectrics,in which the coupling of spontaneous polarization(P_(s))and light favors the dissociation of photo-induced carriers,have taken a booming position within this portfolio.However,polarized-light photodetectors with a low detectionlimit remain unexplored in this 2D ferroelectric family.In this work,the high-quality individual crystals of a 2D perovskite ferroelectric,BA_(2)CsPb_(2)Br_(7)(1,where BA^(+)is n-butylammonium),were used to fabricate ultrasensitive polarized-light detectors.Its unique bilayered structural motif results in quite strong electric and optical anisotropy with a large absorption ratio of a_(c)/α_(a)≈3.2(λ=405 nm).Besides,the presence of ferroelectric Psalso endows high built-in electric field along the polar c-axis that favors photoelectric activities.Under an extremely low detectable limit of 40 n W/cm^(2),the detector of 1 exhibits a notable dichroism ratio(I_(ph)^(c)/I_(ph)^(a)≈1.5),a large responsivity of~39.5 m A/W and a specific detectivity of~1.2×10^(12)Jones.Moreover,crystal-based devices of 1 also exhibit a fast response speed(~300μs)and excellent anti-fatigue merits.This work highlights great potentials of hybrid perovskite ferroelectrics toward polarized-light photodetection.展开更多
The widespread application of phenolic substances in the field of food,medicine and industry,is harmful to the environment and human health.Therefore,it is very important to develop a con-venient and effective method ...The widespread application of phenolic substances in the field of food,medicine and industry,is harmful to the environment and human health.Therefore,it is very important to develop a con-venient and effective method to detect and degrade phenolic compounds.Herein,we report a new keggin-type polyoxometallate-based metal-organic complex self-assembled under solvothermal condition,{[Cu(dap)(3-PA)]4(SiW_(12)O_(40))(H_(2)O)_(2)}·2H_(2)O(1,dap=1,2-diaminopropane,3-HPA=3-pyridineacrylic acid).1 shows an interesting 1D ladder-like structure.As a bifunctional catalyst,1 can be employed as a colori-metric sensor toward phenol with the relatively low detection limit(LOD)of 0.36μmol/L(S/N=3)in the wide range(0.001-0.1 mmol/L).The title colorimetric sensor is applied to determine phenol in various water environment with good recoveries ranging from 95%-105%.In addition,1 also exhibits excellent photocatalytic degradation toward phenol under visible light with the highest removal efficiency at 96%for 100 min and wide pH universality.The selectivity,stability and reliability of the detection of 1 towards phenol,as well as the detection for 4-chlorophenol,o-cresol,4-nitrophenol and phloroglucinol were stud-ied.Furthermore,the photocatalytic reaction kinetics and the mechanisms of photodegradation of phenol were also investigated in detail.展开更多
For determining the accuracy of a calorimeter over the instrument’s entire measuring range,a novel method has been established.For this new approach,(a)benzoic acid(C_(6)H_(5)CO_(2)H) as a certified reference materia...For determining the accuracy of a calorimeter over the instrument’s entire measuring range,a novel method has been established.For this new approach,(a)benzoic acid(C_(6)H_(5)CO_(2)H) as a certified reference material(CRM),(b)SiO_(2) and(c)a mixture of CRM benzoic acid and SiO_(2) have been used.To illustrate the essential difference between 1)the novel analytical method for control of the entire measurement range and 2)the calorimeter calibration,both applications of benzoic acid(BA)have been demonstrated.An experimental result showed that BA was successfully used to check the whole calorimeter measurement range.The results also showed that the same new method was successfully applied to determine the limit of detection and quantification.A new instrument testing process and a new measurement technique have thus been established.In this way,the cost of using CRM to control the accuracy of measuring the entire measuring range of the calorimeter,as shown in this paper,is minimized.The requirements of the ISO/IEC 17025:2017 standard are satisfied.ISO/IEC 17025:2017,together with ISO 9001:2015(quality management systems),ISO 14001:2015(relate to environmental protection)and ISO45001:2018(occupational safety),constitute an integrated quality system by which a testing laboratory may also accredit.展开更多
Chicken is one of the most popular meat products in the world. Salmonella Typhimurium is a common foodbome pathogens associated with the processing of poultry. An optical Surface Plasmon Resonance （SPR） biosensor wa...Chicken is one of the most popular meat products in the world. Salmonella Typhimurium is a common foodbome pathogens associated with the processing of poultry. An optical Surface Plasmon Resonance （SPR） biosensor was sensitive to the presence of Salmonella Typhimurium in chicken carcass. The Spreeta biosensor kits were used to detect Salmonella Typhimurium on chicken carcass successfully. A taste sensor like electronic tongue or biosensors was used to basically ＂taste＂ the object and differentiated one object from the other with different taste sensor signatures. The surface plasmon resonance biosensor has potential for use in rapid, real-time detection and identification of bacteria, and to study the interaction of organisms with dif- ferent antisera or other molecular species. The selectivity of the SPR biosensor was assayed using a series of antibody con- centrations and dilution series of the organism. The SPR biosensor showed promising to detect the existence of Salmonella Typhimurium at 1 x 106 CFU/ml. Initial results show that the SPR biosensor has the potential for its application in pathogenic bacteria monitoring. However, more tests need to be done to confirm the detection limitation.展开更多
Cysteine(Cys)plays a pivotal role in many physiological and pathological processes,including detoxification and protein synthesis.The abnormal levels of Cys are linked to many diseases.In this study,a novel red-emitti...Cysteine(Cys)plays a pivotal role in many physiological and pathological processes,including detoxification and protein synthesis.The abnormal levels of Cys are linked to many diseases.In this study,a novel red-emitting off-on fluorescent probe Cys-TCF was masterly constructed for discriminative detection of Cys.After a series of experimental assessment,Cys-TCF displayed higher selectivity and sensitivity for Cys over other biothilols with a low detection limit(0.04μmol/L).More notably,the probe was also successfully applied to image Cys in live cells and live zebrafishes with low cytotoxicity.展开更多
Ethylene(C2 H4),as a plant hormone,its emission can be served as an indicator to measure fruit quality.Due to the limited physiochemical reactivity of C2 H4,it is a challenge to develop high performance C2 H4 sensors ...Ethylene(C2 H4),as a plant hormone,its emission can be served as an indicator to measure fruit quality.Due to the limited physiochemical reactivity of C2 H4,it is a challenge to develop high performance C2 H4 sensors for fruit detection.Herein,this paper presents a resistive-type C2 H4 sensor based on Pd-loaded tin oxide(SnO2).The C2 H4 sensing performance of proposed sensor are tested at optimum operating temperature(250℃)with ambient relative humidity(51.9%RH).The results show that the response of Pd-loaded SnO2 sensor(11.1,Ra/Rg)is about 3 times higher than that of pristine SnO2(3.5)for 100 ppm C2 H4.The response time is also significantly shortened from 7 s to 1 s compared with pristine SnO2.Especially,the Pd-loaded SnO2 sensor possesses good sensitivity(0.58 ppm 1)at low concentration(0.05-1 ppm)with excellent linearity(R2=0.9963)and low detection limit(50 ppb).The high sensing performance of Pd-loaded SnO2 are attributed to the excellent adsorption and catalysis effects of Pd nanoparticle.Meaningfully,the potential applications of C2 H4 sensor are performed for monitoring the maturity and freshness of fruits,which presents a promising prospect in fruit quality evaluation.展开更多
Although the construction of specific functional crystalline materials is still challenging,the multi-component molecular assembly has become a key solution for the design of functional materials.Here,we report a hydr...Although the construction of specific functional crystalline materials is still challenging,the multi-component molecular assembly has become a key solution for the design of functional materials.Here,we report a hydrogen-bonded organic framework(HOF)material FJU-360 constructed from disodium 6‑hydroxy-5-[(4-sulfophenyl)azo]-2-naphthalenesulfonate(SSY)and terephthalimidamide.The charge-assisted hydrogen bonding between amidinium and sulfonate makes FJU-360 produce much stronger fluorescence than SSY,and can be used as a luminescence sensor to rapidly quench aniline through luminescence quenching.FJU-360 is sensitive and highly selective for the detection of aniline,and the detection limit reached 3.2 nmol/L,which is the lowest value reported currently.The mechanism of aniline response was analyzed through the aniline@FJU-360 single crystal structure,and the luminescence mechanism was clarified through density function theory calculations.This work is an important step towards the rational synthesis and assembly of sensing materials.展开更多
Sub-ppmv level detection of hydrogen sulphide(H_(2)S)using a 1.578-μm distributed feedback tunable diode laser combining with wavelength modulation spectroscopy and second harmonic detection scheme is reported.A home...Sub-ppmv level detection of hydrogen sulphide(H_(2)S)using a 1.578-μm distributed feedback tunable diode laser combining with wavelength modulation spectroscopy and second harmonic detection scheme is reported.A home-developed novel compact dense-pattern multipass gas cell with an effective optical path length of 29.37 m is used to improve sensitivity and reduce sample volume.Detection parameters are optimized,including modulation frequency and amplitude.The analysis of Allan variance shows that a minimum detectable concentration 60 ppbv is obtained with a lock-in time constant of 10 ms,and a detection limit of 13 ppbv can be achieved by average in 300 s.The demonstrated H_(2)S sensor has a strong penitential application in natural gas process for regulating and controlling H_(2)S concentration.展开更多
The multifunctional characteristics of barium zinc vanadate(BaZnV_(2)O_(7))nanoparticles(BZV NPs)were explored in this study,focusing on their photocatalytic activity,supercapacitor performance,and sensing abilities.X...The multifunctional characteristics of barium zinc vanadate(BaZnV_(2)O_(7))nanoparticles(BZV NPs)were explored in this study,focusing on their photocatalytic activity,supercapacitor performance,and sensing abilities.X-ray diffraction analysis confirmed that the crystallites were 40.3 nm in size,whereas ultraviolet visible diffuse reflectance spectroscopy revealed an energy bandgap of 5.28 eV.Functional groups,elemental composition,and morphology were assessed using Fourier transform infrared spectroscopy,energy-dispers-ive X-ray spectroscopy,and scanning electron microscopy,respectively.The photocatalytic efficiency of the BZV NPs was evaluated at various catalyst dosages,dye concentrations,and pH levels,for the degradation of acid black-52(AB-52)dye under UV light.Cyclic voltammetry and galvanostatic charge-discharge analyses were performed to determine the energy storage and cyclic stability of the BZV-NP-modified carbon paste electrode.In addition,a novel electrochemical sensor based on BZV was developed to accurately detect the concentration of biomolecules and chemical drugs.BZV nanoparticles exhibited remarkable photocatalytic dye degradation up to 80.4%,indicating their application in waste water treatment.The BZV-NP-modified carbon paste electrode exhibited a superior specific capacit-ance of 714.15 F·g−1 with excellent cycling stability over 1000 cycles.The electrodes efficiently detected biomolecules such as ascorbic acid and uric acid,chemical drugs including paracetamol and ibuprofen,and heavy metals such as mercury,cobalt,and cadmium in the concentration range of 1-5 mM.The limit of detection(LOD)was measured for all analytes,and the electrode exhibited high sensitivity.These multifunctional properties render BZV promising material for energy storage and environmental monitoring applications.展开更多
The ultralow limit of detection(LoD)and exceptional sensitivity of biosensors are a significant challenge currently faced in the field.To address this challenge,this work proposes a highly sensitive laser ring cavity ...The ultralow limit of detection(LoD)and exceptional sensitivity of biosensors are a significant challenge currently faced in the field.To address this challenge,this work proposes a highly sensitive laser ring cavity biosensor capable of detecting low concentrations of des-γ-carboxy prothrombin(DCP).A tapered W-shaped fiber probe based on multi-mode fiber(MMF)-multi-core fiber(MCF)-MMF is developed to excite strong evanescent waves(EWs).By immobilizing gold nanorods(GNRs)on the fiber probe,localized surface plasmon resonance(LSPR)is generated at the near infrared wavelength to further enhance the sensitivity of the fiber probe.Moreover,an erbium-doped fiber(EDF)ring laser with a narrow full width at half maximum(FWHM)of 0.11 nm is employed as a light source.The spectrum with narrow FWHM has been demonstrated to obtain lower Lo D.Compared to the ASE light source,the Lo D of the laser ring cavity can be reduced by an order of magnitude.The developed biosensor is capable of detecting DCP within a concentration range of 0-1000 ng/mL,and the detection sensitivity of 0.265 nm/lg(ng/mL)and the Lo D of 367.6 pg/m L are obtained.In addition,the proposed laser ring cavity biosensor demonstrates good specificity,reproducibility,and repeatability by corresponding tests.The study results indicate that the proposed biosensor has potential in the detection of hepatocellular carcinoma markers.展开更多
Sensitive and reliable X-ray detectors are essential for medical radiography,industrial inspection and security screening.Lowering the radiation dose allows reduced health risks and increased frequency and fidelity of...Sensitive and reliable X-ray detectors are essential for medical radiography,industrial inspection and security screening.Lowering the radiation dose allows reduced health risks and increased frequency and fidelity of diagnostic technologies for earlier detection of disease and its recurrence.Three-dimensional(3 D)organic-inorganic hybrid lead halide perovskites are promising for direct X-ray detection-they show improved sensitivity compared to conventional X-ray detectors.However,their high and unstable dark current,caused by ion migration and high dark carrier concentration in the 3 D hybrid perovskites,limits their performance and long-term operation stability.Here we report ultrasensitive,stable X-ray detectors made using zero-dimensional(0 D)methylammonium bismuth iodide perovskite(MA3Bi2I9)single crystals.The 0 D crystal structure leads to a high activation energy(Ea)for ion migration(0.46 e V)and is also accompanied by a low dark carrier concentration(~10^6 cm^-3).The X-ray detectors exhibit sensitivity of 10,620μC Gy-1 air cm-2,a limit of detection(Lo D)of 0.62 nG yairs-1,and stable operation even under high applied biases;no deterioration in detection performance was observed following sensing of an integrated X-ray irradiation dose of^23,800 m Gyair,equivalent to>200,000 times the dose required for a single commercial X-ray chest radiograph.Regulating the ion migration channels and decreasing the dark carrier concentration in perovskites provide routes for stable and ultrasensitive X-ray detectors.展开更多
Spatial confinement has great potential for Laser Induced Breakdown Spectroscopy （LIBS） instruments after it has been proven that it has the ability to enhance the LIBS signal strength and repeatability. In order to...Spatial confinement has great potential for Laser Induced Breakdown Spectroscopy （LIBS） instruments after it has been proven that it has the ability to enhance the LIBS signal strength and repeatability. In order to achieve in-situ measurement of heavy metals in farmland soils by LIBS, a hemispherical spatial confinement device is designed and used to collect plasma spectra, in which the optical fibers directly collect the breakdown spectroscopy of the soil samples. This device could effectively increase the stability of the spectrum intensity of soil. It also has other advantages, such as ease of installation, and its small and compact size. The relationship between the spectrum intensity and the laser pulse energy is studied for this device. It is found that the breakdown threshold is 160 cm-2, and when the laser fluence increases to 250 J/cm2, the spectrum intensity reaches its maximum. Four different kinds of laser pulse energy were set up and in each case the limits of detection of Cd, Cu, Ni, Pb and Zn were calculated. The results show that when the laser pulse fluence was 2.12 GW/cm2, we obtained the smallest limits of detection of these heavy metals, which are all under 10 mg/kg. This device can satisfy the needs of heavy metal in-situ detection, and in the next step it will be integrated into a portable LIBS instrument.展开更多
Laser-induced breakdown spectroscopy （LIBS） has been applied to the analysis of heavy metals in liquid samples. A new approach was presented to lower the limit of detection （LOD） and minimize the sample matrix eff...Laser-induced breakdown spectroscopy （LIBS） has been applied to the analysis of heavy metals in liquid samples. A new approach was presented to lower the limit of detection （LOD） and minimize the sample matrix effects, in which dried wood pellets absorbed the given amounts of Cr standard solutions and then were baked because they have stronger and rapid absorption properties for liquid samples as well as simple elemental compositions. In this work, we have taken a typical heavy metal Cr element as an example, and investigated the spectral feasibility of Cr solutions and dried wood pellets before and after absorbing Cr solutions at the same experimental conditions. The results were demonstrated to successfully produce a superior analytical response for heavy metal elements by using wood pellet as sample matrix according to the obtained LOD of 0.07 ppm for Cr element in solutions.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.22435005,22193042,21921001,22305105,52202194,22201284)Natural Science Foundation of Jiangxi Province(No.20224BAB213003)+1 种基金the Natural Science Foundation of Fujian Province(No.2023J05076)Jiangxi Provincial Education Department Science and Technology Research Foundation(No.GJJ2200384)。
文摘Two-dimensional perovskite ferroelectric which strongly couple ferroelectricity with semiconducting properties are promising candidates for optoelectronic applications.However,it is still a great challenge to fabricate self-powered broadband photodetectors with low detection limit.Herein,we successfully realized self-powered broadband photodetection with low detection limit by using a trilayered perovskite ferroelectric(BA)_(2)EA_(2)Pb_(3)I_(10)(1,BA=n-butylamine,EA=ethylamine).Giving to its large spontaneous polarization(5.6μC/cm^(2)),1 exhibits an open-circuit voltage of 0.25 V which provide driving force to separate carriers.Combining with its low dark current(~10^(-14)A)and narrow bandgap(Eg=1.86 e V),1 demonstrates great potential on detecting the broadband weak lights.Thus,a prominent photodetection performance with high open-off ratio(~10^(5)),outstanding responsivity(>10 m A/W),and promising detectivity(>1011Jones),as well as the low detecting limit(~nW/cm^(2))among the wide wavelength from 377 nm to637 nm was realized based on the single crystal of 1.This work demonstrates the great potential of 2D perovskite ferroelectric on self-powered broadband photodetectors.
基金the National Key R&D Program of China(No.2023YFB3210102).
文摘Traditional Pt/C electrode materials are prone to corrosion and detachment during H_(2)S detection,leading to a decrease in fuel cell-type sensor performance.Here,a high-performance H_(2)S sensor based on Pt loaded Ti_(3)C_(2)electrode material with-O/-OH terminal groups was designed and prepared.Experimental tests showed that the Pt/Ti_(3)C_(2)sensor has good sensitivity(0.162μA/ppm)and a very low detection limit to H_(2)S(10 ppb).After 90 days of stability testing,the response of the Pt/Ti_(3)C_(2)sensor shows a smaller decrease of 2%compared to that of the Pt/C sensor(22.9%).Meanwhile,the sensor also has high selectivity and repeatability.The density functional theory(DFT)calculation combined with the experiment results revealed that the improved H_(2)S sensing mechanism is attributed to the fact that the strong interaction between Pt and Ti_(3)C_(2)via the Pt-O-Ti bonding can reduce the formation energy of Pt and Ti_(3)C_(2),ultimately prolonging the sensor’s service life.Furthermore,the catalytic property of Pt can decrease the adsorption energy and dissociation barrier of H_(2)S on Pt/Ti_(3)C_(2)surface,greatly enhance the ability to generate protons and effectively transfer charges,realizing good sensitivity and high selectivity of the sensor.The sensor works at room temperature,making it very promising in the field of H_(2)S detection in future.
基金supported by the National Natural Science Foundation of China(Grant Nos.11074040,11504192,11674187,11604172,and 51403114)the Natural Science Foundation of Shandong Province,China(Grant Nos.ZR2012FZ006 and BS2014CL010)the China Postdoctoral Science Foundation(Grant Nos.2014M551868 and 2015M570570)
文摘A special Fe3O4nanoparticles–graphene（Fe3O4–GN） composite as a magnetic label was employed for biodetection using giant magnetoresistance（GMR） sensors with a Wheatstone bridge. The Fe3O4–GN composite exhibits a strong ferromagnetic behavior with the saturation magnetization MS of approximately 48 emu/g, coercivity HC of 200 Oe, and remanence Mr of 8.3 emu/g, leading to a large magnetic fringing field. However, the Fe3O4 nanoparticles do not aggregate together, which can be attributed to the pinning and separating effects of graphene sheet to the magnetic particles. The Fe3O4–GN composite is especially suitable for biodetection as a promising magnetic label since it combines two advantages of large fringing field and no aggregation. As a result, the concentration x dependence of voltage difference ｜？V｜ between detecting and reference sensors undergoes the relationship of ｜？V｜ = 240.5 lgx ＋ 515.2 with an ultralow detection limit of 10 ng/mL（very close to the calculated limit of 7 ng/mL） and a wide detection range of 4 orders.
基金This work was financially supported fromthe National Natural Science Foundation of China(81303218)Doctoral Fund of China (20130013120006)Special Fund of Outstanding Young Teachers and Innovation Team.
文摘In this work,multivariate detection limits(MDL)estimator was obtained based on the microelectro-mechanical systems–near infrared(MEMS–NIR)technology coupled with two sampling accessories to assess the detection capability of four quality parameters(glycyrrhizic acid,liquiritin,liquiritigenin and isoliquiritin)in licorice from di®erent geographical regions.112 licorice samples were divided into two parts(calibration set and prediction set)using Kennard–Stone(KS)method.Four quality parameters were measured using high-performance liquid chromatography(HPLC)method according to Chinese pharmacopoeia and previous studies.The MEMS–NIR spectra were acquired from¯ber optic probe(FOP)and integrating sphere,then the partial least squares(PLS)model was obtained using the optimum processing method.Chemometrics indicators have been utilized to assess the PLS model performance.Model assessment using chemometrics indicators is based on relative mean prediction error of all concentration levels,which indicated relatively low sensitivity for low-content analytes(below 1000 parts per million(ppm)).Therefore,MDL estimator was introduced with alpha error and beta error based on good prediction characteristic of low concentration levels.The result suggested that MEMS–NIR technology coupled with fiber optic probe(FOP)and integrating sphere was able to detect minor analytes.The result further demonstrated that integrating sphere mode(i.e.,MDL0:05;0:05,0.22%)was more robust than FOP mode(i.e.,MDL0:05;0:05,0.48%).In conclusion,this research proposed that MDL method was helpful to determine the detection capabilities of low-content analytes using MEMS–NIR technology and successful to compare two sampling accessories.
文摘Based on fundamental arguments, the expressions for the decision limit and the detection limit both in the count domain and in the count rate domain are derived.These expressions are found to be different from those shown in the existing literature.
基金financially supported by the National Natural Science Foundation of China(62274103 and 51972194)the National Key Research and Development Program of China(2022YFB3204101)the 111 Project 2.0(BP2018013)。
文摘Lead-halide perovskite single crystal(SC)heterojunctions have attracted significant attention for X-raydetection owing to their unique combination of high sensitivity,resolution,stability and low detection limit.However,the toxicity of lead in those perovskite heterojunctions limitstheir practical applications.Herein,we report the constructionof the first all-inorganic lead-free Cs_(2)AgBiBr_(6)/Cs_(3)Bi_(2)Br_(9)SCheterojunctions with an area of 20×20 mm^(2)via a facile liquidphase epitaxial method through temperature-lowering crystallization.The epitaxial crystallization of the three-dimensional(3D)Cs_(2)AgBiBr_(6)SC film on a 2D Cs_(3)Bi_(2)Br_(9)SCsubstrate requires a large driving force for transitioning fromthe Volmer–Weber mode to the layer-by-layer growth modeunder a rapid cooling rate.The Cs_(2)AgBiBr_(6)/Cs_(3)Bi_(2)Br_(9)SCheterojunction detector achieves a high sensitivity of1390μC Gy_(air)^(−1)cm^(−2)for 100 keV hard X-ray detection atroom temperature,which is enhanced to 2075μC Gy_(air)^(−1)cm^(−2)at 75℃,demonstrating impressive high-temperature stability.Moreover,the detector achieves a detection limit of37.48 nG_(yair)s^(−1)and excellent stability for 90 days without anyencapsulation.This work demonstrates the feasibility of usingthe epitaxial mechanism of perovskite formation on a highsurface-energy substrate for the controllable construction of a3D/2D heterojunction that significantly enhances X-ray detection performance.
基金Natural Environment Research Council,Grant/Award Number:NE/W006871/1。
文摘Recent studies suggest per-and polyfluoroalkyl substances(PFAS)are ubiquitous in rivers worldwide.In the Asia-Pacific region,the frequency of PFAS detection in rivers is increasing.However,the overwhelming majority of studies and data represent high population and urbanized river catchments.In this study,we investigate PFAS occurrence in major Philippines river systems characterized by both high and low population densities.In the Pasig Laguna de Bay River,which drains a major urban conurbation,we detected PFAS at concentrations typical of global rivers.Unexpectedly,we did not detect PFAS in river water or sediments in low population density river catchments,despite our instrument detection limits being lower than the vast majority of river concentrations reported worldwide.We hypothesize that septic tanks,as the dominant wastewater treatment practice in Philippines catchments,may control the release of PFAS into groundwater and rivers in the Philippines.However,no groundwater PFAS data currently exist to validate this supposition.More broadly,our findings highlight the need for more representative PFAS sampling and analysis in rivers to more accurately represent regional and global detection frequencies and trends.
基金supported by the National Natural Science Foundation of China(21622108,21875251,21525104,and 21833010)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB20010200)Youth Innovation Promotion of Chinese Academy of Sciences。
文摘Polarized-light photodetectors are the indispensable elements for practical optical and optoelectronic device applications.Two-dimensional(2D)hybrid perovskite ferroelectrics,in which the coupling of spontaneous polarization(P_(s))and light favors the dissociation of photo-induced carriers,have taken a booming position within this portfolio.However,polarized-light photodetectors with a low detectionlimit remain unexplored in this 2D ferroelectric family.In this work,the high-quality individual crystals of a 2D perovskite ferroelectric,BA_(2)CsPb_(2)Br_(7)(1,where BA^(+)is n-butylammonium),were used to fabricate ultrasensitive polarized-light detectors.Its unique bilayered structural motif results in quite strong electric and optical anisotropy with a large absorption ratio of a_(c)/α_(a)≈3.2(λ=405 nm).Besides,the presence of ferroelectric Psalso endows high built-in electric field along the polar c-axis that favors photoelectric activities.Under an extremely low detectable limit of 40 n W/cm^(2),the detector of 1 exhibits a notable dichroism ratio(I_(ph)^(c)/I_(ph)^(a)≈1.5),a large responsivity of~39.5 m A/W and a specific detectivity of~1.2×10^(12)Jones.Moreover,crystal-based devices of 1 also exhibit a fast response speed(~300μs)and excellent anti-fatigue merits.This work highlights great potentials of hybrid perovskite ferroelectrics toward polarized-light photodetection.
基金supported by the National Natural Science Foundation of China(NSFC,Nos.21901018,21971024,22271021)the Natural Science Foundation and Education Department of Liaoning province(Nos.2022-MS-373,2021-MS-312,LJ2020008).
文摘The widespread application of phenolic substances in the field of food,medicine and industry,is harmful to the environment and human health.Therefore,it is very important to develop a con-venient and effective method to detect and degrade phenolic compounds.Herein,we report a new keggin-type polyoxometallate-based metal-organic complex self-assembled under solvothermal condition,{[Cu(dap)(3-PA)]4(SiW_(12)O_(40))(H_(2)O)_(2)}·2H_(2)O(1,dap=1,2-diaminopropane,3-HPA=3-pyridineacrylic acid).1 shows an interesting 1D ladder-like structure.As a bifunctional catalyst,1 can be employed as a colori-metric sensor toward phenol with the relatively low detection limit(LOD)of 0.36μmol/L(S/N=3)in the wide range(0.001-0.1 mmol/L).The title colorimetric sensor is applied to determine phenol in various water environment with good recoveries ranging from 95%-105%.In addition,1 also exhibits excellent photocatalytic degradation toward phenol under visible light with the highest removal efficiency at 96%for 100 min and wide pH universality.The selectivity,stability and reliability of the detection of 1 towards phenol,as well as the detection for 4-chlorophenol,o-cresol,4-nitrophenol and phloroglucinol were stud-ied.Furthermore,the photocatalytic reaction kinetics and the mechanisms of photodegradation of phenol were also investigated in detail.
基金the funding by the Ministry of Education and Science,the Republic of Serbia for Registration(No.451-03-68/2022-14/200052)。
文摘For determining the accuracy of a calorimeter over the instrument’s entire measuring range,a novel method has been established.For this new approach,(a)benzoic acid(C_(6)H_(5)CO_(2)H) as a certified reference material(CRM),(b)SiO_(2) and(c)a mixture of CRM benzoic acid and SiO_(2) have been used.To illustrate the essential difference between 1)the novel analytical method for control of the entire measurement range and 2)the calorimeter calibration,both applications of benzoic acid(BA)have been demonstrated.An experimental result showed that BA was successfully used to check the whole calorimeter measurement range.The results also showed that the same new method was successfully applied to determine the limit of detection and quantification.A new instrument testing process and a new measurement technique have thus been established.In this way,the cost of using CRM to control the accuracy of measuring the entire measuring range of the calorimeter,as shown in this paper,is minimized.The requirements of the ISO/IEC 17025:2017 standard are satisfied.ISO/IEC 17025:2017,together with ISO 9001:2015(quality management systems),ISO 14001:2015(relate to environmental protection)and ISO45001:2018(occupational safety),constitute an integrated quality system by which a testing laboratory may also accredit.
文摘Chicken is one of the most popular meat products in the world. Salmonella Typhimurium is a common foodbome pathogens associated with the processing of poultry. An optical Surface Plasmon Resonance （SPR） biosensor was sensitive to the presence of Salmonella Typhimurium in chicken carcass. The Spreeta biosensor kits were used to detect Salmonella Typhimurium on chicken carcass successfully. A taste sensor like electronic tongue or biosensors was used to basically ＂taste＂ the object and differentiated one object from the other with different taste sensor signatures. The surface plasmon resonance biosensor has potential for use in rapid, real-time detection and identification of bacteria, and to study the interaction of organisms with dif- ferent antisera or other molecular species. The selectivity of the SPR biosensor was assayed using a series of antibody con- centrations and dilution series of the organism. The SPR biosensor showed promising to detect the existence of Salmonella Typhimurium at 1 x 106 CFU/ml. Initial results show that the SPR biosensor has the potential for its application in pathogenic bacteria monitoring. However, more tests need to be done to confirm the detection limitation.
基金financial supports from the National Natural Science Foundation of China (Nos.21708017,21572093,21778028)Lanzhou University (the Fundamental Research Funds for the Central Universities,No.lzujbky-2018-64)Natural Science Foundation of Gansu Province (No.17JR5RA193)
文摘Cysteine(Cys)plays a pivotal role in many physiological and pathological processes,including detoxification and protein synthesis.The abnormal levels of Cys are linked to many diseases.In this study,a novel red-emitting off-on fluorescent probe Cys-TCF was masterly constructed for discriminative detection of Cys.After a series of experimental assessment,Cys-TCF displayed higher selectivity and sensitivity for Cys over other biothilols with a low detection limit(0.04μmol/L).More notably,the probe was also successfully applied to image Cys in live cells and live zebrafishes with low cytotoxicity.
基金supported by the National Science Funds for Excellent Young Scholars of China(No.61822106)National Science Funds for Creative Research Groups of China(No.61421002)+1 种基金Natural Science Foundation of China(No.61671115)Central Public-interest Scientific Institution Basal Research Fund(No.Y2019XK18)。
文摘Ethylene(C2 H4),as a plant hormone,its emission can be served as an indicator to measure fruit quality.Due to the limited physiochemical reactivity of C2 H4,it is a challenge to develop high performance C2 H4 sensors for fruit detection.Herein,this paper presents a resistive-type C2 H4 sensor based on Pd-loaded tin oxide(SnO2).The C2 H4 sensing performance of proposed sensor are tested at optimum operating temperature(250℃)with ambient relative humidity(51.9%RH).The results show that the response of Pd-loaded SnO2 sensor(11.1,Ra/Rg)is about 3 times higher than that of pristine SnO2(3.5)for 100 ppm C2 H4.The response time is also significantly shortened from 7 s to 1 s compared with pristine SnO2.Especially,the Pd-loaded SnO2 sensor possesses good sensitivity(0.58 ppm 1)at low concentration(0.05-1 ppm)with excellent linearity(R2=0.9963)and low detection limit(50 ppb).The high sensing performance of Pd-loaded SnO2 are attributed to the excellent adsorption and catalysis effects of Pd nanoparticle.Meaningfully,the potential applications of C2 H4 sensor are performed for monitoring the maturity and freshness of fruits,which presents a promising prospect in fruit quality evaluation.
基金supported by the National Natural Science Foundation of China(Nos.21673039,21573042.21805039,21975044,21971038 and 21922810)the Fujian Provincial Department of Education(No.JAT200077).
文摘Although the construction of specific functional crystalline materials is still challenging,the multi-component molecular assembly has become a key solution for the design of functional materials.Here,we report a hydrogen-bonded organic framework(HOF)material FJU-360 constructed from disodium 6‑hydroxy-5-[(4-sulfophenyl)azo]-2-naphthalenesulfonate(SSY)and terephthalimidamide.The charge-assisted hydrogen bonding between amidinium and sulfonate makes FJU-360 produce much stronger fluorescence than SSY,and can be used as a luminescence sensor to rapidly quench aniline through luminescence quenching.FJU-360 is sensitive and highly selective for the detection of aniline,and the detection limit reached 3.2 nmol/L,which is the lowest value reported currently.The mechanism of aniline response was analyzed through the aniline@FJU-360 single crystal structure,and the luminescence mechanism was clarified through density function theory calculations.This work is an important step towards the rational synthesis and assembly of sensing materials.
基金Project supported by the National Key Research and Development Program of China(Grant Nos.2016YFC0303900 and 2017YFC0209700)
文摘Sub-ppmv level detection of hydrogen sulphide(H_(2)S)using a 1.578-μm distributed feedback tunable diode laser combining with wavelength modulation spectroscopy and second harmonic detection scheme is reported.A home-developed novel compact dense-pattern multipass gas cell with an effective optical path length of 29.37 m is used to improve sensitivity and reduce sample volume.Detection parameters are optimized,including modulation frequency and amplitude.The analysis of Allan variance shows that a minimum detectable concentration 60 ppbv is obtained with a lock-in time constant of 10 ms,and a detection limit of 13 ppbv can be achieved by average in 300 s.The demonstrated H_(2)S sensor has a strong penitential application in natural gas process for regulating and controlling H_(2)S concentration.
基金fund provided by the Ongoing Research Funding program-Research Chairs(No.ORF-RC-2025-1609),King Saud University,Riyadh,Saudi Arabia.
文摘The multifunctional characteristics of barium zinc vanadate(BaZnV_(2)O_(7))nanoparticles(BZV NPs)were explored in this study,focusing on their photocatalytic activity,supercapacitor performance,and sensing abilities.X-ray diffraction analysis confirmed that the crystallites were 40.3 nm in size,whereas ultraviolet visible diffuse reflectance spectroscopy revealed an energy bandgap of 5.28 eV.Functional groups,elemental composition,and morphology were assessed using Fourier transform infrared spectroscopy,energy-dispers-ive X-ray spectroscopy,and scanning electron microscopy,respectively.The photocatalytic efficiency of the BZV NPs was evaluated at various catalyst dosages,dye concentrations,and pH levels,for the degradation of acid black-52(AB-52)dye under UV light.Cyclic voltammetry and galvanostatic charge-discharge analyses were performed to determine the energy storage and cyclic stability of the BZV-NP-modified carbon paste electrode.In addition,a novel electrochemical sensor based on BZV was developed to accurately detect the concentration of biomolecules and chemical drugs.BZV nanoparticles exhibited remarkable photocatalytic dye degradation up to 80.4%,indicating their application in waste water treatment.The BZV-NP-modified carbon paste electrode exhibited a superior specific capacit-ance of 714.15 F·g−1 with excellent cycling stability over 1000 cycles.The electrodes efficiently detected biomolecules such as ascorbic acid and uric acid,chemical drugs including paracetamol and ibuprofen,and heavy metals such as mercury,cobalt,and cadmium in the concentration range of 1-5 mM.The limit of detection(LOD)was measured for all analytes,and the electrode exhibited high sensitivity.These multifunctional properties render BZV promising material for energy storage and environmental monitoring applications.
基金Natural Science Foundation of Shandong Province(ZR2022QF137)Double-Hundred Talent Plan of Shandong Province+3 种基金Special Construction Project Fund for Shandong Province Taishan Mountain ScholarsLiaocheng University(318052205,318052341)Science and Technology Support Plan for Youth Innovation of Colleges and Universities of Shandong Province of China(2022KJ107)Koneru Lakshmaiah Education Foundation。
文摘The ultralow limit of detection(LoD)and exceptional sensitivity of biosensors are a significant challenge currently faced in the field.To address this challenge,this work proposes a highly sensitive laser ring cavity biosensor capable of detecting low concentrations of des-γ-carboxy prothrombin(DCP).A tapered W-shaped fiber probe based on multi-mode fiber(MMF)-multi-core fiber(MCF)-MMF is developed to excite strong evanescent waves(EWs).By immobilizing gold nanorods(GNRs)on the fiber probe,localized surface plasmon resonance(LSPR)is generated at the near infrared wavelength to further enhance the sensitivity of the fiber probe.Moreover,an erbium-doped fiber(EDF)ring laser with a narrow full width at half maximum(FWHM)of 0.11 nm is employed as a light source.The spectrum with narrow FWHM has been demonstrated to obtain lower Lo D.Compared to the ASE light source,the Lo D of the laser ring cavity can be reduced by an order of magnitude.The developed biosensor is capable of detecting DCP within a concentration range of 0-1000 ng/mL,and the detection sensitivity of 0.265 nm/lg(ng/mL)and the Lo D of 367.6 pg/m L are obtained.In addition,the proposed laser ring cavity biosensor demonstrates good specificity,reproducibility,and repeatability by corresponding tests.The study results indicate that the proposed biosensor has potential in the detection of hepatocellular carcinoma markers.
基金supported by the National Natural Science Foundation of China(Grant nos.21773218,61974063)the Sichuan Province(Grant no.2018JY0206)the China Academy of Engineering Physics(Grant no.YZJJLX2018007)。
文摘Sensitive and reliable X-ray detectors are essential for medical radiography,industrial inspection and security screening.Lowering the radiation dose allows reduced health risks and increased frequency and fidelity of diagnostic technologies for earlier detection of disease and its recurrence.Three-dimensional(3 D)organic-inorganic hybrid lead halide perovskites are promising for direct X-ray detection-they show improved sensitivity compared to conventional X-ray detectors.However,their high and unstable dark current,caused by ion migration and high dark carrier concentration in the 3 D hybrid perovskites,limits their performance and long-term operation stability.Here we report ultrasensitive,stable X-ray detectors made using zero-dimensional(0 D)methylammonium bismuth iodide perovskite(MA3Bi2I9)single crystals.The 0 D crystal structure leads to a high activation energy(Ea)for ion migration(0.46 e V)and is also accompanied by a low dark carrier concentration(~10^6 cm^-3).The X-ray detectors exhibit sensitivity of 10,620μC Gy-1 air cm-2,a limit of detection(Lo D)of 0.62 nG yairs-1,and stable operation even under high applied biases;no deterioration in detection performance was observed following sensing of an integrated X-ray irradiation dose of^23,800 m Gyair,equivalent to>200,000 times the dose required for a single commercial X-ray chest radiograph.Regulating the ion migration channels and decreasing the dark carrier concentration in perovskites provide routes for stable and ultrasensitive X-ray detectors.
文摘Spatial confinement has great potential for Laser Induced Breakdown Spectroscopy （LIBS） instruments after it has been proven that it has the ability to enhance the LIBS signal strength and repeatability. In order to achieve in-situ measurement of heavy metals in farmland soils by LIBS, a hemispherical spatial confinement device is designed and used to collect plasma spectra, in which the optical fibers directly collect the breakdown spectroscopy of the soil samples. This device could effectively increase the stability of the spectrum intensity of soil. It also has other advantages, such as ease of installation, and its small and compact size. The relationship between the spectrum intensity and the laser pulse energy is studied for this device. It is found that the breakdown threshold is 160 cm-2, and when the laser fluence increases to 250 J/cm2, the spectrum intensity reaches its maximum. Four different kinds of laser pulse energy were set up and in each case the limits of detection of Cd, Cu, Ni, Pb and Zn were calculated. The results show that when the laser pulse fluence was 2.12 GW/cm2, we obtained the smallest limits of detection of these heavy metals, which are all under 10 mg/kg. This device can satisfy the needs of heavy metal in-situ detection, and in the next step it will be integrated into a portable LIBS instrument.
基金supported by National Natural Science Foundation of China(Nos.11064012,11274254,11364037)the JSPS-NRF-NSFC A3 Foresight Program in the Field of Plasma Physics(No.11261140328)the International Scientic and Technologic Cooperative Project of Gansu Province,China(No.1104WCGA186)
文摘Laser-induced breakdown spectroscopy （LIBS） has been applied to the analysis of heavy metals in liquid samples. A new approach was presented to lower the limit of detection （LOD） and minimize the sample matrix effects, in which dried wood pellets absorbed the given amounts of Cr standard solutions and then were baked because they have stronger and rapid absorption properties for liquid samples as well as simple elemental compositions. In this work, we have taken a typical heavy metal Cr element as an example, and investigated the spectral feasibility of Cr solutions and dried wood pellets before and after absorbing Cr solutions at the same experimental conditions. The results were demonstrated to successfully produce a superior analytical response for heavy metal elements by using wood pellet as sample matrix according to the obtained LOD of 0.07 ppm for Cr element in solutions.
