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2019 Volume 36 Issue 8
2019, 36(8): 855-881
doi: 10.11944/j.issn.1000-0518.2019.08.190142
Abstract:
Organic field effect transistors(OFETs) are the basic components of the next generation of flexible electronics industry, which are bendable, transparent and solution-processible, and gradually begin to be applied to biosensors, flexible display and other fields. However, OFETs still have problems such as small operating current, small transconductance, low switching ratio, and poor air stability, which limits their further development. The performance of OFETs devices is mainly affected by the distribution of charge and current in the conductive channel. If the charge and current distribution in the channel are properly controlled by external means, it is possible to obtain a device with higher performance or new mechanism. The latest progress on this field is reviewed and prospected, which includes the recent result from our group.
Organic field effect transistors(OFETs) are the basic components of the next generation of flexible electronics industry, which are bendable, transparent and solution-processible, and gradually begin to be applied to biosensors, flexible display and other fields. However, OFETs still have problems such as small operating current, small transconductance, low switching ratio, and poor air stability, which limits their further development. The performance of OFETs devices is mainly affected by the distribution of charge and current in the conductive channel. If the charge and current distribution in the channel are properly controlled by external means, it is possible to obtain a device with higher performance or new mechanism. The latest progress on this field is reviewed and prospected, which includes the recent result from our group.
2019, 36(8): 882-891
doi: 10.11944/j.issn.1000-0518.2019.08.190126
Abstract:
Low temperature plasma belongs to a non-thermal equilibrium plasma, which has higher electron temperature and lower gas temperature. It is a new method to prepare and modify nanometer catalyst. Low-temperature plasma has attracted much attention in the preparation and modification of nano-catalytic materials because of its high efficiency, environmental protection, and easy functionalization. It exhibits outstanding advantages in the unconventional preparation, doping, manufacturing defects and vacancies of nano-catalytic materials, and thus is widely used in the preparation and modification of various catalysts. In this paper, we mainly introduced the research progress of low temperature plasma in the preparation and modification of catalysts such as oxygen reduction reaction(ORR), oxygen evolution reaction(OER), hydrogen evolution reaction(HER), fuel oxidation reaction(FOR), and the reasons for improving the performance of various catalysts were discussed. The challenges of low temperature plasma in the preparation and modification of nano-catalysts were summarized, such as relatively high cost, reactor amplification, material controllable preparation and so on. At last, the development tendency of using low temperature plasma to prepare and modify the catalyst was forecasted.
Low temperature plasma belongs to a non-thermal equilibrium plasma, which has higher electron temperature and lower gas temperature. It is a new method to prepare and modify nanometer catalyst. Low-temperature plasma has attracted much attention in the preparation and modification of nano-catalytic materials because of its high efficiency, environmental protection, and easy functionalization. It exhibits outstanding advantages in the unconventional preparation, doping, manufacturing defects and vacancies of nano-catalytic materials, and thus is widely used in the preparation and modification of various catalysts. In this paper, we mainly introduced the research progress of low temperature plasma in the preparation and modification of catalysts such as oxygen reduction reaction(ORR), oxygen evolution reaction(OER), hydrogen evolution reaction(HER), fuel oxidation reaction(FOR), and the reasons for improving the performance of various catalysts were discussed. The challenges of low temperature plasma in the preparation and modification of nano-catalysts were summarized, such as relatively high cost, reactor amplification, material controllable preparation and so on. At last, the development tendency of using low temperature plasma to prepare and modify the catalyst was forecasted.
2019, 36(8): 892-896
doi: 10.11944/j.issn.1000-0518.2019.08.180418
Abstract:
Alkyl, aryl and bifunctional isothiocyanates were synthesized in moderate to excellent yields(77%~96%) in a two-step and one-pot reaction. The reaction were started with parent primary amines, carbon disulfide in toluene in presence of N, N-diethyl-ethanamine(Et3N) at room temperature, followed by reaction of the thus formed dithiocarbamates with t-butylcarbonic diethylphoric anhydride(3) from -5℃ to room temperature. The best molar ratio of substrates was n(primary amines):n(CS2):n(Et3N):n(3)=1:1.1:3.3:1.1. The procedure was quite simple and the substrate scope is broad. This method is compatible with a variety of protecting groups and the chiral center in investigated compounds. Compound 3 was used as an new commericial available safe and efficient desulfurization reagent.
Alkyl, aryl and bifunctional isothiocyanates were synthesized in moderate to excellent yields(77%~96%) in a two-step and one-pot reaction. The reaction were started with parent primary amines, carbon disulfide in toluene in presence of N, N-diethyl-ethanamine(Et3N) at room temperature, followed by reaction of the thus formed dithiocarbamates with t-butylcarbonic diethylphoric anhydride(3) from -5℃ to room temperature. The best molar ratio of substrates was n(primary amines):n(CS2):n(Et3N):n(3)=1:1.1:3.3:1.1. The procedure was quite simple and the substrate scope is broad. This method is compatible with a variety of protecting groups and the chiral center in investigated compounds. Compound 3 was used as an new commericial available safe and efficient desulfurization reagent.
2019, 36(8): 897-903
doi: 10.11944/j.issn.1000-0518.2019.08.180409
Abstract:
To develope an efficiently structural modification strategy for transforming antibacterial fluoroquinolone into antitumor agent, novel N-arylidene arylidene rhodanine levofloxacin amide derivatives(6a-6n) were synthesized via amide modification with functionalized arylidene rhodanine scaffold as the bioisostere of the C-3 carboxylic group. The in vitro antitumor assay indicated that the title compounds exhibited more significant potency against three test cancer cell lines than levofloxacin, but with lower cytotoxicity against the normal cells than doxorubicin as a comparison. The SAR(structure-activity relationship) reveals that the increase in the bulky or electron-donating substituents bearing phenyl ring obviously reduces the antitumor activity. Conversely, compounds with electron-withdrawing nitro-or fluorophenyl or heteroaromatic rings such as furan or pyridine ring display comparable activity to doxorubicin. Thus, an amide group modified by arylidene rhodanine scaffold as an isostere of the C-3 carboxylic acid group appears to an alternative route for further design of antitumor fluoroquinolone.
To develope an efficiently structural modification strategy for transforming antibacterial fluoroquinolone into antitumor agent, novel N-arylidene arylidene rhodanine levofloxacin amide derivatives(6a-6n) were synthesized via amide modification with functionalized arylidene rhodanine scaffold as the bioisostere of the C-3 carboxylic group. The in vitro antitumor assay indicated that the title compounds exhibited more significant potency against three test cancer cell lines than levofloxacin, but with lower cytotoxicity against the normal cells than doxorubicin as a comparison. The SAR(structure-activity relationship) reveals that the increase in the bulky or electron-donating substituents bearing phenyl ring obviously reduces the antitumor activity. Conversely, compounds with electron-withdrawing nitro-or fluorophenyl or heteroaromatic rings such as furan or pyridine ring display comparable activity to doxorubicin. Thus, an amide group modified by arylidene rhodanine scaffold as an isostere of the C-3 carboxylic acid group appears to an alternative route for further design of antitumor fluoroquinolone.
2019, 36(8): 904-908
doi: 10.11944/j.issn.1000-0518.2019.08.190024
Abstract:
Based on the high reactivity of carboxyl and epoxy groups, crosslinked polyolefins were successfully prepared by reactive blending of ethylene-glycidyl methacrylate copolymer(PE-GMA) and ethylene acrylic acid copolymer(EAA). The thermodynamic properties and shape memory effect of the obtained polymer were measured by differential scanning calorimeter(DSC) and dynamic mechanical thermal analyses(DMA). The dual-shape memory effect, multi-shape memory effect and two-way shape memory effect were achieved due to the broad distribution of crystallite sizes of the crosslinked polyolefins. By the aid of photothermal effect of graphene oxide(GO), photothermal-induced shape memory effect was also realized. The "temperature gradient" strategy was successfully applied to the photothermal-induced two-way shape memory effect of the crosslinked polyolefins.
Based on the high reactivity of carboxyl and epoxy groups, crosslinked polyolefins were successfully prepared by reactive blending of ethylene-glycidyl methacrylate copolymer(PE-GMA) and ethylene acrylic acid copolymer(EAA). The thermodynamic properties and shape memory effect of the obtained polymer were measured by differential scanning calorimeter(DSC) and dynamic mechanical thermal analyses(DMA). The dual-shape memory effect, multi-shape memory effect and two-way shape memory effect were achieved due to the broad distribution of crystallite sizes of the crosslinked polyolefins. By the aid of photothermal effect of graphene oxide(GO), photothermal-induced shape memory effect was also realized. The "temperature gradient" strategy was successfully applied to the photothermal-induced two-way shape memory effect of the crosslinked polyolefins.
2019, 36(8): 909-916
doi: 10.11944/j.issn.1000-0518.2019.08.180370
Abstract:
Poly(styrene sulfonic acid)-graft-poly(vinylidene fluoride)(PSSA-g-PVDF) membrane was prepared via phase bulk modification with tetramethylammonium hydroxide(TMAH), grafting styrene sulfonic acid(SSA) onto PVDF with benzoyl peroxide(BPO) as an initiator. After that, the copolymer was casted into a flat membrane via immersion phase inversion. It was investigated that TMAH content has effect on grafting degree(GD) and the oil/water separation membrane performance of PSSA. At the same time, Fourier transform infrared spectrum(FTIR), scanning electron microscope(SEM) and video optical contact angle measuring test were adopted to measure the membrane structure and surface contact angle. The results showed that the partial HF was eliminated from PVDF by TMAH forming carbon double bonds and styrene sulfonic acid was grafted onto the modified PVDF skeletons. The GD of PSSA-g-PVDF membrane increased as more TMAH used. The optimized hydrophilicity of modified PVDF membrane was obtained with 20% of TMAH, when the GD of membrane was 22.1%. The contact angle of the separation membrane was reduced to 37.2° within 30 s. Water flux was 643.3 L/(m·h). Rejection rate was 90.6% and the water flux recovery rate was 93.7%. The attenuation rate was 7.1%. The cycle test showed that the water flux recovery rate and oil-water flux recovery rate of the membrane were both above 90%.
Poly(styrene sulfonic acid)-graft-poly(vinylidene fluoride)(PSSA-g-PVDF) membrane was prepared via phase bulk modification with tetramethylammonium hydroxide(TMAH), grafting styrene sulfonic acid(SSA) onto PVDF with benzoyl peroxide(BPO) as an initiator. After that, the copolymer was casted into a flat membrane via immersion phase inversion. It was investigated that TMAH content has effect on grafting degree(GD) and the oil/water separation membrane performance of PSSA. At the same time, Fourier transform infrared spectrum(FTIR), scanning electron microscope(SEM) and video optical contact angle measuring test were adopted to measure the membrane structure and surface contact angle. The results showed that the partial HF was eliminated from PVDF by TMAH forming carbon double bonds and styrene sulfonic acid was grafted onto the modified PVDF skeletons. The GD of PSSA-g-PVDF membrane increased as more TMAH used. The optimized hydrophilicity of modified PVDF membrane was obtained with 20% of TMAH, when the GD of membrane was 22.1%. The contact angle of the separation membrane was reduced to 37.2° within 30 s. Water flux was 643.3 L/(m·h). Rejection rate was 90.6% and the water flux recovery rate was 93.7%. The attenuation rate was 7.1%. The cycle test showed that the water flux recovery rate and oil-water flux recovery rate of the membrane were both above 90%.
2019, 36(8): 917-923
doi: 10.11944/j.issn.1000-0518.2019.08.190013
Abstract:
Chloromethylated polysulfones(CPS) was used as the precursors, and side chain type sulfonted polysulfone(PS-BDS) was obtained using disodium 1, 2-dihydroxybenzene-3, 5-disufonate as nucleophilic reagents. The corresponding proton exchange membranes(PEMs) were produced using solution casting method. The relationship between the temperature and properties of PEMs was studied. Since they have characteristic micro-phase separation structures by locating hydrophilic sulfonic acid group far away from hydrophobic main chain of PS, PEMs have excellent dimensional stability at high water sorption ratio. With the increase of temperature, the proton conductivity, the swelling ratio and the water sorption ratio increase. PS-BDS PEMs have comprehensive size stability and methanol permeability. The swelling ratio of PS-BDS-4 PEM is only 22.1% at 25℃ and 55.0% at 85℃. The methanol permeability is 9.94×10-7 cm2/s at 25℃, lower than those of commercial Nafion115(16.8×10-7 cm2/s) and Nafion117(23.8×10-7 cm2/s) PEMs.
Chloromethylated polysulfones(CPS) was used as the precursors, and side chain type sulfonted polysulfone(PS-BDS) was obtained using disodium 1, 2-dihydroxybenzene-3, 5-disufonate as nucleophilic reagents. The corresponding proton exchange membranes(PEMs) were produced using solution casting method. The relationship between the temperature and properties of PEMs was studied. Since they have characteristic micro-phase separation structures by locating hydrophilic sulfonic acid group far away from hydrophobic main chain of PS, PEMs have excellent dimensional stability at high water sorption ratio. With the increase of temperature, the proton conductivity, the swelling ratio and the water sorption ratio increase. PS-BDS PEMs have comprehensive size stability and methanol permeability. The swelling ratio of PS-BDS-4 PEM is only 22.1% at 25℃ and 55.0% at 85℃. The methanol permeability is 9.94×10-7 cm2/s at 25℃, lower than those of commercial Nafion115(16.8×10-7 cm2/s) and Nafion117(23.8×10-7 cm2/s) PEMs.
2019, 36(8): 924-931
doi: 10.11944/j.issn.1000-0518.2019.08.190097
Abstract:
The properties of LiZnPO4 are closely related to its morphology. The solid state method and the hydrothermal method are widely used for synthesis of LiZnPO4, neither has the advantage of controlling the morphology of LiZnPO4. In this paper, the rod-shaped LiZnPO4 was successfully synthesized by the modified precipitation method. The forming process, phases, microstructure and morphology of LiZnPO4 were investigated by thermogravimetry coupled with differential scanning calorimetry(TG-DSC), X-ray diffraction(XRD), Fourier transform infrared spectroscopy(FTIR) and field emission scanning electron microscopy(FE-SEM). The effects of synthesis methods, calcination temperature and time, acid types on the morphology of LiZnPO4 were also explored. The results show that, compared with the solid state method, the modified precipitation method with acetic acid can not only effectively reduce the synthesis temperature of LiZnPO4 to 500℃, but also easily control the formation of rod-shaped LiZnPO4. LiZnPO4 can be obtained at 600℃ for 2 h by the modified precipitation method with acetic acid, which is regular in rod shape with good dispersibility, rectangular cross section and diameter of about 2 μm. In addition, it was found that the light response capacity of the rod-shaped LiZnPO4 was significantly enhanced compared with that of the LiZnPO4 particles without regular morphology.
The properties of LiZnPO4 are closely related to its morphology. The solid state method and the hydrothermal method are widely used for synthesis of LiZnPO4, neither has the advantage of controlling the morphology of LiZnPO4. In this paper, the rod-shaped LiZnPO4 was successfully synthesized by the modified precipitation method. The forming process, phases, microstructure and morphology of LiZnPO4 were investigated by thermogravimetry coupled with differential scanning calorimetry(TG-DSC), X-ray diffraction(XRD), Fourier transform infrared spectroscopy(FTIR) and field emission scanning electron microscopy(FE-SEM). The effects of synthesis methods, calcination temperature and time, acid types on the morphology of LiZnPO4 were also explored. The results show that, compared with the solid state method, the modified precipitation method with acetic acid can not only effectively reduce the synthesis temperature of LiZnPO4 to 500℃, but also easily control the formation of rod-shaped LiZnPO4. LiZnPO4 can be obtained at 600℃ for 2 h by the modified precipitation method with acetic acid, which is regular in rod shape with good dispersibility, rectangular cross section and diameter of about 2 μm. In addition, it was found that the light response capacity of the rod-shaped LiZnPO4 was significantly enhanced compared with that of the LiZnPO4 particles without regular morphology.
2019, 36(8): 932-938
doi: 10.11944/j.issn.1000-0518.2019.08.190016
Abstract:
Highly efficient and polychromatic luminescent CsPbX3 perovskite quantum dots(PQDs) were synthesized under room temperature. The entire reaction is very fast and simple. Polychromatic luminescence of CsPbX3 PQDs can be achieved by adjusting different halide compositions(Cl, Br, I). The as-prepared CsPbX3 PQDs have a cubic morphology with an average size about 10 nm. The photoluminescence of CsPbX3 PQDs has a characteristic of wide visible spectral region of 410~630 nm, narrow emission line-widths of 14~38 nm and quantum yields of 10%~90%. Finally, the CsPbX3 PQDs are successfully applied to prepare light emitting diode(LED) devices. At a constant voltage work for a long time, the emission color, intensity, and color coordinates of the LED device remain unchanged.
Highly efficient and polychromatic luminescent CsPbX3 perovskite quantum dots(PQDs) were synthesized under room temperature. The entire reaction is very fast and simple. Polychromatic luminescence of CsPbX3 PQDs can be achieved by adjusting different halide compositions(Cl, Br, I). The as-prepared CsPbX3 PQDs have a cubic morphology with an average size about 10 nm. The photoluminescence of CsPbX3 PQDs has a characteristic of wide visible spectral region of 410~630 nm, narrow emission line-widths of 14~38 nm and quantum yields of 10%~90%. Finally, the CsPbX3 PQDs are successfully applied to prepare light emitting diode(LED) devices. At a constant voltage work for a long time, the emission color, intensity, and color coordinates of the LED device remain unchanged.
2019, 36(8): 939-948
doi: 10.11944/j.issn.1000-0518.2019.08.190004
Abstract:
TiO2 coated gold nanorods with core-shell structure(GNR@TiO2) about 200 nm were synthesized by sol-gel process and hydrothermal method. After hydrothermal crystallization, the particle size of the material expands to 300 nm, while the morphology and the local surface plasmon resonance(LSPR) of GNR have no change. The structure and properties of the samples were characterized by X-ray diffraction(XRD), high resolution transmission electron microscope(HRTEM), X-ray photoelectron spectroscopy(XPS), ultraviolet-visible absorption spectroscopy and photocatalytic hydrogen production. The results show that the hydrogen production rate of crystallized GNR@TiO2 is 31.0 μmol/(g·h) in the visible light range, which is much higher than that of 7.3 μmol/(g·h) before crystallization. Based on experimental result and finite difference time domain(FDTD) analysis, we proposed a photocatalytic mechanism for efficient hydrogen generation. LSPR promotes the visible light absorption. Anatase TiO2 enhances the electric field and promotes the photogenerated electron-hole separation. The crystallized TiO2 shell is porous and multi-mesoporous, which increases the active sites and is conducive to material transfer.
TiO2 coated gold nanorods with core-shell structure(GNR@TiO2) about 200 nm were synthesized by sol-gel process and hydrothermal method. After hydrothermal crystallization, the particle size of the material expands to 300 nm, while the morphology and the local surface plasmon resonance(LSPR) of GNR have no change. The structure and properties of the samples were characterized by X-ray diffraction(XRD), high resolution transmission electron microscope(HRTEM), X-ray photoelectron spectroscopy(XPS), ultraviolet-visible absorption spectroscopy and photocatalytic hydrogen production. The results show that the hydrogen production rate of crystallized GNR@TiO2 is 31.0 μmol/(g·h) in the visible light range, which is much higher than that of 7.3 μmol/(g·h) before crystallization. Based on experimental result and finite difference time domain(FDTD) analysis, we proposed a photocatalytic mechanism for efficient hydrogen generation. LSPR promotes the visible light absorption. Anatase TiO2 enhances the electric field and promotes the photogenerated electron-hole separation. The crystallized TiO2 shell is porous and multi-mesoporous, which increases the active sites and is conducive to material transfer.
2019, 36(8): 949-957
doi: 10.11944/j.issn.1000-0518.2019.08.180415
Abstract:
The ligand N, N'-bis(thiophenaldehyde) ethylenediamine(L) obtained by the condensation between 2-thiophene carboxaldehyde and ethylenediamine were used for synthesis of new complexes[ZnLCl2](1) and[NiL'(NO3)2](2)(L'-thiophenaldehyde-ethylenediamine). The structures of these complexes and ligand were characterized by single crystal X-ray analysis. These compounds were used for modifying the surface of TiO2. The obtained photocatalysts(L-TiO2, 1-TiO2, 2-TiO2) were characterized by IR spectra, UV-Vis diffuse reflectance spectroscopy and XRD. Their photocatalytic activities in the photodegradation of 4-nitrophenol(4-NP) and Rhodamine B(RhB) were evaluated under UV-visible light irradiation. The results revealed higher photocatalytic activities of 1-TiO2 and 2-TiO2 than that of bare TiO2. In addition, the degradation rate can reach above 90%.
The ligand N, N'-bis(thiophenaldehyde) ethylenediamine(L) obtained by the condensation between 2-thiophene carboxaldehyde and ethylenediamine were used for synthesis of new complexes[ZnLCl2](1) and[NiL'(NO3)2](2)(L'-thiophenaldehyde-ethylenediamine). The structures of these complexes and ligand were characterized by single crystal X-ray analysis. These compounds were used for modifying the surface of TiO2. The obtained photocatalysts(L-TiO2, 1-TiO2, 2-TiO2) were characterized by IR spectra, UV-Vis diffuse reflectance spectroscopy and XRD. Their photocatalytic activities in the photodegradation of 4-nitrophenol(4-NP) and Rhodamine B(RhB) were evaluated under UV-visible light irradiation. The results revealed higher photocatalytic activities of 1-TiO2 and 2-TiO2 than that of bare TiO2. In addition, the degradation rate can reach above 90%.
2019, 36(8): 958-967
doi: 10.11944/j.issn.1000-0518.2019.08.180414
Abstract:
A novel molecularly imprinted electrochemical sensor with specific recognition ability to template molecules and its structural analogs were prepared by electro-polymerization. Cyhalothrin was used as the template molecule and o-phenylenediamine and o-aminophenol as composite functional monomers. The imprinting effect and analytical performance of the sensor were characterized by cyclic voltammetry and square wave voltammetry. A rapid analysis method was established for determination of cyhalothrin residues in agricultural products. Under the optimal conditions, the linear relationship of cyhalothrin was good within the concentration range of 1.0×10-7~1.0×10-5 mol/L, and the detection limit(S/N=3) was 3.0×10-8 mol/L, the average recoveries of spiked sample were between 84.8% and 94.7%, and the relative standard deviations(RSDs) were 1.1%~4.8%(n=5). This sensor has advantages of simple operation, detection speediness, high sensitivity, low cost, good selectivity, stability and reproducibility, which provides it a good application prospect.
A novel molecularly imprinted electrochemical sensor with specific recognition ability to template molecules and its structural analogs were prepared by electro-polymerization. Cyhalothrin was used as the template molecule and o-phenylenediamine and o-aminophenol as composite functional monomers. The imprinting effect and analytical performance of the sensor were characterized by cyclic voltammetry and square wave voltammetry. A rapid analysis method was established for determination of cyhalothrin residues in agricultural products. Under the optimal conditions, the linear relationship of cyhalothrin was good within the concentration range of 1.0×10-7~1.0×10-5 mol/L, and the detection limit(S/N=3) was 3.0×10-8 mol/L, the average recoveries of spiked sample were between 84.8% and 94.7%, and the relative standard deviations(RSDs) were 1.1%~4.8%(n=5). This sensor has advantages of simple operation, detection speediness, high sensitivity, low cost, good selectivity, stability and reproducibility, which provides it a good application prospect.
2019, 36(8): 968-976
doi: 10.11944/j.issn.1000-0518.2019.08.190011
Abstract:
Fifty pesticides in Angelica sinensis, were determined by ultra-high performance liquid chromatography/tandem mass spectrometry(UPLC-MS/MS). Through comparing 11 kinds of purification methods, the best effective matrix purification method was selected. The pesticide residues were extracted from samples with acetoniteile, cleaned-up with NaCl and then analyzed using UPLC-MS/MS in dynamic multiple reaction monitoring(dMRM) mode with positive and negative electrospray ionization. The pesticide residues were quantified by matrix matched standard solution-internal standard method. All calibration curves showed good linearity(R2 > 0.99) within the test ranges. The average recoveries of most pesticides at the spiked levels of 10, 50, 100 μg/kg ranged from 70.1%~117.7% with RSDs of 1.0%~20.0%. The limits of quantification of 50 pesticides were 1.0~20.0 μg/kg. The method provides a reliable basis for accurate, efficient and economical detection of targeted analytes in Angelica sinensis.
Fifty pesticides in Angelica sinensis, were determined by ultra-high performance liquid chromatography/tandem mass spectrometry(UPLC-MS/MS). Through comparing 11 kinds of purification methods, the best effective matrix purification method was selected. The pesticide residues were extracted from samples with acetoniteile, cleaned-up with NaCl and then analyzed using UPLC-MS/MS in dynamic multiple reaction monitoring(dMRM) mode with positive and negative electrospray ionization. The pesticide residues were quantified by matrix matched standard solution-internal standard method. All calibration curves showed good linearity(R2 > 0.99) within the test ranges. The average recoveries of most pesticides at the spiked levels of 10, 50, 100 μg/kg ranged from 70.1%~117.7% with RSDs of 1.0%~20.0%. The limits of quantification of 50 pesticides were 1.0~20.0 μg/kg. The method provides a reliable basis for accurate, efficient and economical detection of targeted analytes in Angelica sinensis.
