The laser-induced breakdown spectroscopy technique has irreplaceable advantages in the field of detection due to its multi-phase specimen detection ability.The development of the LIBS technique for liquid analysis is ...The laser-induced breakdown spectroscopy technique has irreplaceable advantages in the field of detection due to its multi-phase specimen detection ability.The development of the LIBS technique for liquid analysis is obstructed by its inherent drawbacks like the surface ripples and extinction of emitted intensity,which make it unpractical.In this work,an in-situ hydrogel formation sampling device was designed and used the hydrogel as the detection phase of LIBS for Cu,Cr and Al in an aqueous solution.With the measured amount of resin placed in the device,the formed hydrogel could be obtained within 20 s after putting the device into water solution.The formed hydrogel could be directly analyzed by LIBS and reflect the elemental information of the water sample.The prominent performance made this hydrogel＇s formation device especially suitable for quick in-situ environmental liquid analysis using LIBS.展开更多
An improved method for trace level quantification of dicyandiamide in stream water has been developed. This method includes sample pretreatment using solid phase extraction.The extraction procedure（including loading,...An improved method for trace level quantification of dicyandiamide in stream water has been developed. This method includes sample pretreatment using solid phase extraction.The extraction procedure（including loading, washing, and eluting） used a flow rate of1.0 m L/min, and dicyandiamide was eluted with 20 m L of a methanol/acetonitrile mixture（V/V = 2：3）, followed by pre-concentration using nitrogen evaporation and analysis with high performance liquid chromatography–ultraviolet spectroscopy（HPLC–UV）. Sample extraction was carried out using a Waters Sep-Pak AC-2 Cartridge（with activated carbon）.Separation was achieved on a ZIC-Hydrophilic Interaction Liquid Chromatography（ZIC-HILIC）（50 mm × 2.1 mm, 3.5 μm） chromatography column and quantification was accomplished based on UV absorbance. A reliable linear relationship was obtained for the calibration curve using standard solutions（R^2〉 0.999）. Recoveries for dicyandiamide ranged from 84.6% to 96.8%, and the relative standard deviations（RSDs, n = 3） were below 6.1% with a detection limit of 5.0 ng/m L for stream water samples.展开更多
Objective:To assess the detection efficiencies of liquid radioisotopes in a well-type NaI(Tl)gamma spectrometer,focusing on the short-lived isotopes^(99)Tcm,^(131)I,and^(18)F.Methods:The detection efficiencies of liqu...Objective:To assess the detection efficiencies of liquid radioisotopes in a well-type NaI(Tl)gamma spectrometer,focusing on the short-lived isotopes^(99)Tcm,^(131)I,and^(18)F.Methods:The detection efficiencies of liquid 99Tcm,131I,and 18F in a well-type NaI(Tl)gamma spectrometer were systematically investigated through calibration experiments and Monte Carlo simulations,and accounting for the coincidence-summing effect.Results:The results indicated that the detection efficiencies of^(99)Tcm,^(131)I,and^(18)F varied from 64.4%to 72.3%,34.8%-43.1%and 27.3%-28.5%for different sample volumes ranging from 15 mL to 80 mL,respectively.The simulated detection efficiencies were highly consistent with the experimental results,with a largest relative deviation of 5%for the 3 radionuclides and 4 different sample volumes.Conclusion:The consistent results between the calibration experiments and Monte Carlo simulations reveal that this measuring device possesses high detection efficiencies of 99Tcm,131I,and 18F,making it suitable for measuring low-level activity radioactive liquids,such as radioactive waste liquids to be discharged.展开更多
Given recent interest in laboratory automation and miniaturization,the microdroplet research space has expanded across research disciplines and sectors.In turn,the microdroplet field is continually evolving and seekin...Given recent interest in laboratory automation and miniaturization,the microdroplet research space has expanded across research disciplines and sectors.In turn,the microdroplet field is continually evolving and seeking new methods to generate microdroplets,especially in ways that can be integrated into diverse(microfluidic)workflows.Herein,we present a convenient,low-cost,and re-usable microdroplet generation device,termed as the“NanoWand,”which enables microdroplet formation in the nanoliter volume range through modulated surface energy and roughness,that is,an open surface energy trap(oSET),using commercially available and readily assembled coating and substrate materials.A wand-like shape is excised from a microscope glass cover slip via laser-micromachining and rendered hydrophobic;a circle is then cut-out from the hydrophobically modified wand’s tip using laser-micromachining to create the oSET.By adjusting the size of the oSET with laser-micromachining,the volume of the microdroplet can be similarly controlled.Using liquid microjunction-surface sampling probe-mass spectrometry(LMJ-SSPMS),specific NanoWand droplet capture volumeswere estimated to be 117±23.6 nL,198±30.3 nL,and 277±37.1 nL,corresponding to oSET diameters of 0.75,1.00,and 1.25 mm,respectively.This simple approach provides a user-friendly way to form and transfer microdroplets that could be integrated into different liquid handling applications,especially when combined with the LMJ-SSP and ambient ionization MS as a powerful and rapid analytical tool.展开更多
The development of laser sampling for optical emission spectrometry is reviewed . Advantages and limitations of pulsed laser sampling are compared with those of continuous laser sampling . A novel method of laser samp...The development of laser sampling for optical emission spectrometry is reviewed . Advantages and limitations of pulsed laser sampling are compared with those of continuous laser sampling . A novel method of laser sampling of liquid samples for inductively coupled plasma -atomic emission spectrometry has been proposed , and its analytical performance investigated.Experimental results showed that,as a method of sample introduction , laser vaporization of liquid samples enjoyed certain advantages , e.g.,much higher sensitivity, much lower detection limit and reduced sample volume , over solution nebulization . A perspective of the application of laser sampling-inductively coupled plasma - actomic emission spectrometry for rock and mineral analysis is estimated as well.展开更多
文摘The laser-induced breakdown spectroscopy technique has irreplaceable advantages in the field of detection due to its multi-phase specimen detection ability.The development of the LIBS technique for liquid analysis is obstructed by its inherent drawbacks like the surface ripples and extinction of emitted intensity,which make it unpractical.In this work,an in-situ hydrogel formation sampling device was designed and used the hydrogel as the detection phase of LIBS for Cu,Cr and Al in an aqueous solution.With the measured amount of resin placed in the device,the formed hydrogel could be obtained within 20 s after putting the device into water solution.The formed hydrogel could be directly analyzed by LIBS and reflect the elemental information of the water sample.The prominent performance made this hydrogel＇s formation device especially suitable for quick in-situ environmental liquid analysis using LIBS.
基金Department of Chemistry at Mississippi State University for financial support for this project
文摘An improved method for trace level quantification of dicyandiamide in stream water has been developed. This method includes sample pretreatment using solid phase extraction.The extraction procedure（including loading, washing, and eluting） used a flow rate of1.0 m L/min, and dicyandiamide was eluted with 20 m L of a methanol/acetonitrile mixture（V/V = 2：3）, followed by pre-concentration using nitrogen evaporation and analysis with high performance liquid chromatography–ultraviolet spectroscopy（HPLC–UV）. Sample extraction was carried out using a Waters Sep-Pak AC-2 Cartridge（with activated carbon）.Separation was achieved on a ZIC-Hydrophilic Interaction Liquid Chromatography（ZIC-HILIC）（50 mm × 2.1 mm, 3.5 μm） chromatography column and quantification was accomplished based on UV absorbance. A reliable linear relationship was obtained for the calibration curve using standard solutions（R^2〉 0.999）. Recoveries for dicyandiamide ranged from 84.6% to 96.8%, and the relative standard deviations（RSDs, n = 3） were below 6.1% with a detection limit of 5.0 ng/m L for stream water samples.
基金supported by the State Administration for Market Regulation Innovation Talent Program(No.QNBJ202304)Shanghai Municipal Health Commission(No.GWVI-11.1-40)Science and Technology Program of the Shanghai Municipal Administration for Market Regulation,(No.2022–07),China.
文摘Objective:To assess the detection efficiencies of liquid radioisotopes in a well-type NaI(Tl)gamma spectrometer,focusing on the short-lived isotopes^(99)Tcm,^(131)I,and^(18)F.Methods:The detection efficiencies of liquid 99Tcm,131I,and 18F in a well-type NaI(Tl)gamma spectrometer were systematically investigated through calibration experiments and Monte Carlo simulations,and accounting for the coincidence-summing effect.Results:The results indicated that the detection efficiencies of^(99)Tcm,^(131)I,and^(18)F varied from 64.4%to 72.3%,34.8%-43.1%and 27.3%-28.5%for different sample volumes ranging from 15 mL to 80 mL,respectively.The simulated detection efficiencies were highly consistent with the experimental results,with a largest relative deviation of 5%for the 3 radionuclides and 4 different sample volumes.Conclusion:The consistent results between the calibration experiments and Monte Carlo simulations reveal that this measuring device possesses high detection efficiencies of 99Tcm,131I,and 18F,making it suitable for measuring low-level activity radioactive liquids,such as radioactive waste liquids to be discharged.
基金Natural Sciences and Engineering Research Council(NSERC),Grant/Award Number:RGPIN-2022-03833CMC Microsystems,Grant/Award Numbers:10268,10731。
文摘Given recent interest in laboratory automation and miniaturization,the microdroplet research space has expanded across research disciplines and sectors.In turn,the microdroplet field is continually evolving and seeking new methods to generate microdroplets,especially in ways that can be integrated into diverse(microfluidic)workflows.Herein,we present a convenient,low-cost,and re-usable microdroplet generation device,termed as the“NanoWand,”which enables microdroplet formation in the nanoliter volume range through modulated surface energy and roughness,that is,an open surface energy trap(oSET),using commercially available and readily assembled coating and substrate materials.A wand-like shape is excised from a microscope glass cover slip via laser-micromachining and rendered hydrophobic;a circle is then cut-out from the hydrophobically modified wand’s tip using laser-micromachining to create the oSET.By adjusting the size of the oSET with laser-micromachining,the volume of the microdroplet can be similarly controlled.Using liquid microjunction-surface sampling probe-mass spectrometry(LMJ-SSPMS),specific NanoWand droplet capture volumeswere estimated to be 117±23.6 nL,198±30.3 nL,and 277±37.1 nL,corresponding to oSET diameters of 0.75,1.00,and 1.25 mm,respectively.This simple approach provides a user-friendly way to form and transfer microdroplets that could be integrated into different liquid handling applications,especially when combined with the LMJ-SSP and ambient ionization MS as a powerful and rapid analytical tool.
文摘The development of laser sampling for optical emission spectrometry is reviewed . Advantages and limitations of pulsed laser sampling are compared with those of continuous laser sampling . A novel method of laser sampling of liquid samples for inductively coupled plasma -atomic emission spectrometry has been proposed , and its analytical performance investigated.Experimental results showed that,as a method of sample introduction , laser vaporization of liquid samples enjoyed certain advantages , e.g.,much higher sensitivity, much lower detection limit and reduced sample volume , over solution nebulization . A perspective of the application of laser sampling-inductively coupled plasma - actomic emission spectrometry for rock and mineral analysis is estimated as well.
