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2020 Volume 48 Issue 4
2020, 48(4): 431-438
doi: 10.19756/j.issn.0253-3820.191674
Abstract:
Cu(I)-catalyzed azide-alkyne specific reaction, popularly known as the "click chemistry reaction", is defined as an important molecular connection method, which can realize simple and efficient connection between specific small molecule groups at the molecular level. Because of its advantages such as high efficiency, high selectivity, mild conditions and few side reactions, click chemistry reaction has been widely used in proteomics analysis, including the identification of newly synthesized proteins and the identification of various post-translational modified proteins. Therefore, in-depth study of the reaction mechanism of click chemistry reaction in proteomics is very important for understanding the structure and function of proteins. The goal of this review is to highlight the progress of several important applications of click chemistry in proteomics analysis in recent years, and discuss the future trends of the click chemistry in proteomics.
Cu(I)-catalyzed azide-alkyne specific reaction, popularly known as the "click chemistry reaction", is defined as an important molecular connection method, which can realize simple and efficient connection between specific small molecule groups at the molecular level. Because of its advantages such as high efficiency, high selectivity, mild conditions and few side reactions, click chemistry reaction has been widely used in proteomics analysis, including the identification of newly synthesized proteins and the identification of various post-translational modified proteins. Therefore, in-depth study of the reaction mechanism of click chemistry reaction in proteomics is very important for understanding the structure and function of proteins. The goal of this review is to highlight the progress of several important applications of click chemistry in proteomics analysis in recent years, and discuss the future trends of the click chemistry in proteomics.
2020, 48(4): 439-448
doi: 10.19756/j.issn.0253-3820.191682
Abstract:
Microfluidic systems are widely applied in many fields including chemistry, biology, medicine, and pharmacy, because of their precise control ability to microfluids. In recent years, artificial intelligence technology has achieved leap-forward development with great advantages in dealing with the analysis and mining of massive data. The application of artificial intelligence technology in microfluidic systems has shown great potential in many fields such as biological research, medical diagnosis, and drug discovery, and so on. This paper reviews several typical artificial intelligence models and their applications in microfluidic systems. It focuses on the progress of artificial intelligence in target detection, correlation prediction and result classification of microfluidic systems, and forecasts the future development trend based on its application status.
Microfluidic systems are widely applied in many fields including chemistry, biology, medicine, and pharmacy, because of their precise control ability to microfluids. In recent years, artificial intelligence technology has achieved leap-forward development with great advantages in dealing with the analysis and mining of massive data. The application of artificial intelligence technology in microfluidic systems has shown great potential in many fields such as biological research, medical diagnosis, and drug discovery, and so on. This paper reviews several typical artificial intelligence models and their applications in microfluidic systems. It focuses on the progress of artificial intelligence in target detection, correlation prediction and result classification of microfluidic systems, and forecasts the future development trend based on its application status.
2020, 48(4): 449-462
doi: 10.19756/j.issn.0253-3820.191235
Abstract:
SO2, NOx and NH3 are low molecular weight inorganic gas and are commonly found in the atmosphere that can affect the formation and chemical composition of secondary organic aerosols (SOA) through photochemical reaction processes. Volatile organic compounds (VOCs) from motor vehicle exhaust, such as monoaromatic hydrocarbons, are an important component of urban fine particulate matter, which has a significant impact on climate change, human health and atmospheric visibility. However, previous studies focused on photooxidation of biogenic volatile organic compounds, and relatively few on the reaction of anthropogenic monoaromatic hydrocarbons with high content in the atmosphere with inorganic gases such as SO2, NOx and NH3. This paper summarizes the photochemical mechanism and five kinds of common chemical composition of the laboratory simulation of OH radical to initiate monoaromatic hydrocarbons formation of SOA, and the effects of SO2, NOx and NH3 on the formation and chemical composition of monoaromatic hydrocarbons SOA by homogeneous and heterogeneous chemical reactions are also discussed. It is helpful to understand the formation mechanism and chemical composition of SOA and atmospheric brown carbon under the conditions of complex atmospheric pollution, and has certain reference significance for the prevention, control and treatment of air pollution in china at present.
SO2, NOx and NH3 are low molecular weight inorganic gas and are commonly found in the atmosphere that can affect the formation and chemical composition of secondary organic aerosols (SOA) through photochemical reaction processes. Volatile organic compounds (VOCs) from motor vehicle exhaust, such as monoaromatic hydrocarbons, are an important component of urban fine particulate matter, which has a significant impact on climate change, human health and atmospheric visibility. However, previous studies focused on photooxidation of biogenic volatile organic compounds, and relatively few on the reaction of anthropogenic monoaromatic hydrocarbons with high content in the atmosphere with inorganic gases such as SO2, NOx and NH3. This paper summarizes the photochemical mechanism and five kinds of common chemical composition of the laboratory simulation of OH radical to initiate monoaromatic hydrocarbons formation of SOA, and the effects of SO2, NOx and NH3 on the formation and chemical composition of monoaromatic hydrocarbons SOA by homogeneous and heterogeneous chemical reactions are also discussed. It is helpful to understand the formation mechanism and chemical composition of SOA and atmospheric brown carbon under the conditions of complex atmospheric pollution, and has certain reference significance for the prevention, control and treatment of air pollution in china at present.
2020, 48(4): 463-472
doi: 10.19756/j.issn.0253-3820.191610
Abstract:
The octa-electrode linear ion trap (OeLIT) can achieve a good mass analysis performance with a specific radio frequency (RF) voltage application. In this work, the influence of three types of electrode misregistration on mass analysis performance of OeLIT was simulated. The internal electric field distribution induced by electrode misregistration was modified by optimizing RF voltage difference δ, and the performance self-repairing was realized without any changes of ion trap structures. It was found that the performance degradation caused by ion electrode misregistration could be compensated only by adjusting δ values. Besides, the optimal mass resolution was 3622.7, which was comparable to that of OeLIT without electrode misregistration.
The octa-electrode linear ion trap (OeLIT) can achieve a good mass analysis performance with a specific radio frequency (RF) voltage application. In this work, the influence of three types of electrode misregistration on mass analysis performance of OeLIT was simulated. The internal electric field distribution induced by electrode misregistration was modified by optimizing RF voltage difference δ, and the performance self-repairing was realized without any changes of ion trap structures. It was found that the performance degradation caused by ion electrode misregistration could be compensated only by adjusting δ values. Besides, the optimal mass resolution was 3622.7, which was comparable to that of OeLIT without electrode misregistration.
2020, 48(4): 473-483
doi: 10.19756/j.issn.0253-3820.191726
Abstract:
A microfluidic device for specifically capturing Escherichia coli O157∶H7(E.coli O157∶H7) was developed. To capture E.coli O157∶H7 cells with the device, the surface of microfluidic chip was modified by the tetrahedral DNA nanostructures, and the nucleic acid aptamers as the capture probes were linked through the biotin-streptavidin reaction for detection of E.coli O157∶H7 cells. The microfluidic chip containing herringbone structures was designed to reduce the shear force when the bacteria were captured. Modification of DNA tetrahedron on the surface of polydimethylsiloxane (PDMS) chip could further regulate the distance between the probes and improved the recognition efficiency of the probes and bacteria. The successful preparation of DNA tetrahedron nanostructures and the construction of DNA tetrahedron-aptamers system were confirmed by agarose gel electrophoretic. Fluorescence microscopy was used to further imaging and analysis of the detection results. Finally, the tetrahedral DNA nanostructures-based microfluidic platform was also used for the detection of the real food samples. The results showed that without the assistance of large instruments or equipment and other signal amplification techniques, the detection system could be used to successfully detect E.coli O157∶H7 with a concentration of 10 CFU/mL under the ordinary optical microscope, and the detection time was no more than 2 h. Moreover, in the actual sample detection, the recoveries were 88.3%-108.3%. The developed strategy of microfluidic platform based on tetrahedral DNA nanostructure not only provided an effective detection method for food borne pathogens, but also had potential application value in other research fields such as potential food safety hazards and early diagnosis of diseases.
A microfluidic device for specifically capturing Escherichia coli O157∶H7(E.coli O157∶H7) was developed. To capture E.coli O157∶H7 cells with the device, the surface of microfluidic chip was modified by the tetrahedral DNA nanostructures, and the nucleic acid aptamers as the capture probes were linked through the biotin-streptavidin reaction for detection of E.coli O157∶H7 cells. The microfluidic chip containing herringbone structures was designed to reduce the shear force when the bacteria were captured. Modification of DNA tetrahedron on the surface of polydimethylsiloxane (PDMS) chip could further regulate the distance between the probes and improved the recognition efficiency of the probes and bacteria. The successful preparation of DNA tetrahedron nanostructures and the construction of DNA tetrahedron-aptamers system were confirmed by agarose gel electrophoretic. Fluorescence microscopy was used to further imaging and analysis of the detection results. Finally, the tetrahedral DNA nanostructures-based microfluidic platform was also used for the detection of the real food samples. The results showed that without the assistance of large instruments or equipment and other signal amplification techniques, the detection system could be used to successfully detect E.coli O157∶H7 with a concentration of 10 CFU/mL under the ordinary optical microscope, and the detection time was no more than 2 h. Moreover, in the actual sample detection, the recoveries were 88.3%-108.3%. The developed strategy of microfluidic platform based on tetrahedral DNA nanostructure not only provided an effective detection method for food borne pathogens, but also had potential application value in other research fields such as potential food safety hazards and early diagnosis of diseases.
2020, 48(4): 484-490
doi: 10.19756/j.issn.0253-3820.191581
Abstract:
As an important part of joint, synovial fluid (SF) plays an important role in joint movement, lubrication and protection. The changes in main components of SF (proteins, proteoglycans, etc.) indicate osteoarthritis (OA) development, which may be used as biomarkers for OA diagnosis. Since detection sensitivity of Raman scattering is limited, it's hard to realize micro/trace composition detection of SF. Due to high sensitivity and high specificity, surface-enhanced Raman scattering (SERS) has become a preferred option for micro/trace detection. In this study, diluted serum and hyaluronic acid (HA) were used to verify the SERS feasibility in SF detection by the self-made nano silver sol. The SF drawn from the knee joint with 8-week OA (early OA) was investigated by SERS technique, and it was found that the scattering intensities of the protein, polysaccharide and pyranose ring were obviously enhanced, which could be used for the micro detection of SF. By comparing SERS spectra of SFs of the early OA and the health, it was found that contents of polysaccharide HA, sulfated polysaccharide and pyranose increased in the OA, showing significant differences with those in the health (p<0.05). The method proposed here opened up a promising and novel way to early OA diagnosis and micro/trace detection of biological tissue fluids.
As an important part of joint, synovial fluid (SF) plays an important role in joint movement, lubrication and protection. The changes in main components of SF (proteins, proteoglycans, etc.) indicate osteoarthritis (OA) development, which may be used as biomarkers for OA diagnosis. Since detection sensitivity of Raman scattering is limited, it's hard to realize micro/trace composition detection of SF. Due to high sensitivity and high specificity, surface-enhanced Raman scattering (SERS) has become a preferred option for micro/trace detection. In this study, diluted serum and hyaluronic acid (HA) were used to verify the SERS feasibility in SF detection by the self-made nano silver sol. The SF drawn from the knee joint with 8-week OA (early OA) was investigated by SERS technique, and it was found that the scattering intensities of the protein, polysaccharide and pyranose ring were obviously enhanced, which could be used for the micro detection of SF. By comparing SERS spectra of SFs of the early OA and the health, it was found that contents of polysaccharide HA, sulfated polysaccharide and pyranose increased in the OA, showing significant differences with those in the health (p<0.05). The method proposed here opened up a promising and novel way to early OA diagnosis and micro/trace detection of biological tissue fluids.
2020, 48(4): 491-497
doi: 10.19756/j.issn.0253-3820.191648
Abstract:
A vacuum ultraviolet photoionization nucleation aerosol mass spectrometer (VUVPI-AMS) was utilized for detection of chemical compositions of ultrafine nanoparticles with size less than 100 nm. A commercial nano scanning mobility particle sizer (Nano-SMPS) was employed to size-select ultrafine nanoparticles and measure their size distribution. A special aerodynamic lens was developed to transfer and focus the ultrafine nanoparticle into the vacuum. After heated on the surface of the heater, the ultrafine nanoparticles were vaporized and changed into gas-phase molecules, followed by softly photoionization at their ionization energy thresholds by the VUV light emitted from a commercial 10.6 eV krypton discharge lamp. A home-made orthogonal acceleration reflection time-of-flight mass analyzer was adopted to measure the mass of ions. As representative examples, the dioctyl phthalate (DOP) ultrafine nanoparticles and the nucleation nanoparticles from the ozonolysis reaction of α-pinene with ozone were studied and their chemical compositions were obtained with molecular information.
A vacuum ultraviolet photoionization nucleation aerosol mass spectrometer (VUVPI-AMS) was utilized for detection of chemical compositions of ultrafine nanoparticles with size less than 100 nm. A commercial nano scanning mobility particle sizer (Nano-SMPS) was employed to size-select ultrafine nanoparticles and measure their size distribution. A special aerodynamic lens was developed to transfer and focus the ultrafine nanoparticle into the vacuum. After heated on the surface of the heater, the ultrafine nanoparticles were vaporized and changed into gas-phase molecules, followed by softly photoionization at their ionization energy thresholds by the VUV light emitted from a commercial 10.6 eV krypton discharge lamp. A home-made orthogonal acceleration reflection time-of-flight mass analyzer was adopted to measure the mass of ions. As representative examples, the dioctyl phthalate (DOP) ultrafine nanoparticles and the nucleation nanoparticles from the ozonolysis reaction of α-pinene with ozone were studied and their chemical compositions were obtained with molecular information.
2020, 48(4): 498-506
doi: 10.19756/j.issn.0253-3820.191662
Abstract:
A dual-signal proportional immunosensor for detection of C-reactive protein was developed using gold-nanoparticles (AuNPs) functionalized metal-organic frameworks (MOFs) material (AuNPs /Fe-MIL-88-NH2) as an immobilized matrix and signal unit. The octahedral Fe-MOFs can not only provide a larger effective surface area, but also increase the amount of immobilized biomolecules and promote the transport of electrons and ions, and also exhibit good electrical conductivity. Modification of AuNPs onto Fe-MOFs can further increase specific surface area to capture large amounts of antibodies and increase electron transfer capacity. With increase of CRP concentration, the oxidation peak current of K3Fe(CN)6/K4Fe(CN)6 decreases, while the oxidation peak current in Fe-MOFs is relatively constant. The response current ratio of K3Fe(CN)6/K4 Fe(CN)6 to Fe-MOFs has been used as a quantitative measurement of CRP response signal. Fe-MOFs modified by K3Fe(CN)6/K4Fe(CN)6 as a signal probe (K3Fe(CN)6/K4Fe(CN)6-sP) and AuNPs as internal reference probes (Fe-MOFs-rP). This ratio probe integrates sP and rP into one structure, ensuring identical modification conditions and the interdependence of sP and rP on a sensing interface. Therefore, this ratiometric probe has a stronger ability to eliminate environmental variation interference. The linear response of the immunosensor proposed here ranges from 1 to 200 ng/mL, and the detection limit is 0.3 ng/mL (S/N=3). The sensor has good selectivity and is expected to be used for early screening and diagnosis of cardiovascular disease. The method also lays the foundation for the preparation of other ratiometric signal amplification sensors for detecting biomarkers.
A dual-signal proportional immunosensor for detection of C-reactive protein was developed using gold-nanoparticles (AuNPs) functionalized metal-organic frameworks (MOFs) material (AuNPs /Fe-MIL-88-NH2) as an immobilized matrix and signal unit. The octahedral Fe-MOFs can not only provide a larger effective surface area, but also increase the amount of immobilized biomolecules and promote the transport of electrons and ions, and also exhibit good electrical conductivity. Modification of AuNPs onto Fe-MOFs can further increase specific surface area to capture large amounts of antibodies and increase electron transfer capacity. With increase of CRP concentration, the oxidation peak current of K3Fe(CN)6/K4Fe(CN)6 decreases, while the oxidation peak current in Fe-MOFs is relatively constant. The response current ratio of K3Fe(CN)6/K4 Fe(CN)6 to Fe-MOFs has been used as a quantitative measurement of CRP response signal. Fe-MOFs modified by K3Fe(CN)6/K4Fe(CN)6 as a signal probe (K3Fe(CN)6/K4Fe(CN)6-sP) and AuNPs as internal reference probes (Fe-MOFs-rP). This ratio probe integrates sP and rP into one structure, ensuring identical modification conditions and the interdependence of sP and rP on a sensing interface. Therefore, this ratiometric probe has a stronger ability to eliminate environmental variation interference. The linear response of the immunosensor proposed here ranges from 1 to 200 ng/mL, and the detection limit is 0.3 ng/mL (S/N=3). The sensor has good selectivity and is expected to be used for early screening and diagnosis of cardiovascular disease. The method also lays the foundation for the preparation of other ratiometric signal amplification sensors for detecting biomarkers.
2020, 48(4): 507-515
doi: 10.19756/j.issn.0253-3820.191335
Abstract:
A "turn on-off" fluorescent probe based on aptamer/gold nanoparticles(AuNPs) was developed for rapid, highly sensitive and selective detection of isocarbophos (ICP). Hairpin complementary strand (cDNA) with a fluorescein label (FAM) at 5' end was attached to the surface of AuNPs through thiol group. Subsequently, ICP-binding aptamer (ICP-Aptamer) was added and hybridized with cDNA, leading to open of hairpin assembly and "turn on" of fluorescent signal quenched by AuNPs. ICP-Aptamer specifically bound to the target ICP with restoration of configuration and "turn off" of the fluorescent signal. The properties of nanoparticles were characterized by transmission electron microscopy, ultraviolet-visible absorption spectroscopy and zeta potential. Experimental parameters influencing fluorescence inhibition rate, including pH value, concentration of ICP-Aptamer, incubation time and incubation temperature, were investigated and optimized. The corresponding fluorescence inhibition rate had a good linear relationship with concentration of ICP in the range of 0.02-10 μmol/L, and the limit of detection was 17.8 nmol/L. Furthermore,the fluorescent probe was applied to determination of ICP in rice and spinach samples. The recoveries were from 92.9% to 107.0% and the relative standard deviations were lower than 4.2%. It could be concluded that the fluorescence probe had good application potential for detection of pesticides and supervision of food safety.
A "turn on-off" fluorescent probe based on aptamer/gold nanoparticles(AuNPs) was developed for rapid, highly sensitive and selective detection of isocarbophos (ICP). Hairpin complementary strand (cDNA) with a fluorescein label (FAM) at 5' end was attached to the surface of AuNPs through thiol group. Subsequently, ICP-binding aptamer (ICP-Aptamer) was added and hybridized with cDNA, leading to open of hairpin assembly and "turn on" of fluorescent signal quenched by AuNPs. ICP-Aptamer specifically bound to the target ICP with restoration of configuration and "turn off" of the fluorescent signal. The properties of nanoparticles were characterized by transmission electron microscopy, ultraviolet-visible absorption spectroscopy and zeta potential. Experimental parameters influencing fluorescence inhibition rate, including pH value, concentration of ICP-Aptamer, incubation time and incubation temperature, were investigated and optimized. The corresponding fluorescence inhibition rate had a good linear relationship with concentration of ICP in the range of 0.02-10 μmol/L, and the limit of detection was 17.8 nmol/L. Furthermore,the fluorescent probe was applied to determination of ICP in rice and spinach samples. The recoveries were from 92.9% to 107.0% and the relative standard deviations were lower than 4.2%. It could be concluded that the fluorescence probe had good application potential for detection of pesticides and supervision of food safety.
2020, 48(4): 516-522
doi: 10.19756/j.issn.0253-3820.191545
Abstract:
pH and uric acid (UA) flexible electrode were prepared by mixing carbon powder and luteolin or L-argining as functional selective reagents in a polyvinyl chloride (PVC) film for detection of pH value and UA concentration respectively. A flexible integrated electrochemical sensor (FIES) were designed, in which pH flexible electrode(pH/FE), UA flexible electrode (UA/FE), self-made thin film-gel model Ag/AgCl reference electrode and Pt wire electrode were placed on plastic film, then were embedded by a conduct film containing PVC-agar membrane saturated with KCl, the surface of the working electrode was exposed. Phosphate buffer solution (PBS) in the range of pH=2.00-8.00 was dripped on the surface of FIES, respectively, and the results showed that there was an oxidation peak on square wave voltammetry (SWV) curve when the pH/FE was used as work electrode. The peak potential was linear with the pH value of PBS. UA in PBS was dripped onto the surface of FIES, and its electrochemical behavior was studied by SWV when the UA/FE was used as working electrode. An oxidation peak was observed, and the peak current and UA concentration had a linear relationship in the range of 5.0×10-6-1.3×10-4 mol/L, and the detection limit was 2.0×10-7 mol/L. FIES could be directly attached on the skin surface to determine the pH value of sweat and UA concentration.
pH and uric acid (UA) flexible electrode were prepared by mixing carbon powder and luteolin or L-argining as functional selective reagents in a polyvinyl chloride (PVC) film for detection of pH value and UA concentration respectively. A flexible integrated electrochemical sensor (FIES) were designed, in which pH flexible electrode(pH/FE), UA flexible electrode (UA/FE), self-made thin film-gel model Ag/AgCl reference electrode and Pt wire electrode were placed on plastic film, then were embedded by a conduct film containing PVC-agar membrane saturated with KCl, the surface of the working electrode was exposed. Phosphate buffer solution (PBS) in the range of pH=2.00-8.00 was dripped on the surface of FIES, respectively, and the results showed that there was an oxidation peak on square wave voltammetry (SWV) curve when the pH/FE was used as work electrode. The peak potential was linear with the pH value of PBS. UA in PBS was dripped onto the surface of FIES, and its electrochemical behavior was studied by SWV when the UA/FE was used as working electrode. An oxidation peak was observed, and the peak current and UA concentration had a linear relationship in the range of 5.0×10-6-1.3×10-4 mol/L, and the detection limit was 2.0×10-7 mol/L. FIES could be directly attached on the skin surface to determine the pH value of sweat and UA concentration.
2020, 48(4): 523-529
doi: 10.19756/j.issn.0253-3820.191707
Abstract:
A ultrasonic extraction combining single particle-inductively coupled plasma-mass spectrometry (SP-ICP-MS) method was developed to detect the size distribution, number concentrations and mass concentrations of silver nanoparticles (AgNPs) in toothpaste. AgNPs in toothpaste were extracted by sonication with 0.1% Tx-100 solvent, and SP-ICP-MS method was used for the determination of size distribution, number concentration and mass concentration of the AgNPs. The optimum extraction time, accuracy, detection limit of particle size, number concentration and mass concentration of the method were investigated. The result showed that in the optimum extraction time of 10 min, the particle sizes of AgNPs in diluent of toothpaste determined by SP-ICP-MS were consistent with the standard values provided by the manufacturer. The detection limits of particle size, number concentration and mass concentration were 23 nm, 3.9×108 particles/kg and 26 ng/kg, respectively. The spiking recoveries of AgNPs in toothpaste were 86.6%-93.8%. The proposed method showed high sensitivity and accuracy in determination of size distribution and number concentrations of AgNPs in toothpaste.
A ultrasonic extraction combining single particle-inductively coupled plasma-mass spectrometry (SP-ICP-MS) method was developed to detect the size distribution, number concentrations and mass concentrations of silver nanoparticles (AgNPs) in toothpaste. AgNPs in toothpaste were extracted by sonication with 0.1% Tx-100 solvent, and SP-ICP-MS method was used for the determination of size distribution, number concentration and mass concentration of the AgNPs. The optimum extraction time, accuracy, detection limit of particle size, number concentration and mass concentration of the method were investigated. The result showed that in the optimum extraction time of 10 min, the particle sizes of AgNPs in diluent of toothpaste determined by SP-ICP-MS were consistent with the standard values provided by the manufacturer. The detection limits of particle size, number concentration and mass concentration were 23 nm, 3.9×108 particles/kg and 26 ng/kg, respectively. The spiking recoveries of AgNPs in toothpaste were 86.6%-93.8%. The proposed method showed high sensitivity and accuracy in determination of size distribution and number concentrations of AgNPs in toothpaste.
2020, 48(4): 530-535
doi: 10.19756/j.issn.0253-3820.191577
Abstract:
A vortex-assisted liquid-liquid extraction protocol followed by inductively coupled plasma optical emission spectrometer (ICP-OES) was developed for determination of nine elements (Cr, Mn, Fe, Ni, Cu, As, Zn, Cd, and Pb) in olive oil samples. The experiment was performed under optimum conditions including 5% HNO3 (V/V) and vortex-assisted extraction for 5 min. Dichloromethane was used to make the extraction solvent to the upper layer, which increased the ratio of oil-extraction solvent to 1∶1 (m/V). Quantification limits were 0.01-0.05 mg/kg, which was satisfied with the request of determination of legislated metals in olive oil samples. The accuracy of the method was assessed by spiking experiments and comparison of the results from the extraction procedure with those obtained by national standard method of China. The recoveries were 90.2%-103.6% with RSD less than 5%. No statistical differences, based on t-test at a confidence level of 95%, were detected between two methods. The proposed method was simple, fast and accurate in determination of olive oil samples.
A vortex-assisted liquid-liquid extraction protocol followed by inductively coupled plasma optical emission spectrometer (ICP-OES) was developed for determination of nine elements (Cr, Mn, Fe, Ni, Cu, As, Zn, Cd, and Pb) in olive oil samples. The experiment was performed under optimum conditions including 5% HNO3 (V/V) and vortex-assisted extraction for 5 min. Dichloromethane was used to make the extraction solvent to the upper layer, which increased the ratio of oil-extraction solvent to 1∶1 (m/V). Quantification limits were 0.01-0.05 mg/kg, which was satisfied with the request of determination of legislated metals in olive oil samples. The accuracy of the method was assessed by spiking experiments and comparison of the results from the extraction procedure with those obtained by national standard method of China. The recoveries were 90.2%-103.6% with RSD less than 5%. No statistical differences, based on t-test at a confidence level of 95%, were detected between two methods. The proposed method was simple, fast and accurate in determination of olive oil samples.
2020, 48(4): 536-542
doi: 10.19756/j.issn.0253-3820.191677
Abstract:
Benzoboric acid adsorbent was prepared tenderly for adsorption of trace luteoloside from Coreopsis tinctoria. Without desorption, the enriched samples were detected directly by near-infrared (NIR) diffuse reflectance spectroscopy method. To predict its content, a quantitative correction model for luteoloside was established by partial least square regression method. The results illustrated that the adsorption efficiency was 85.5% when 0.2 g of benzoboric acid adsorbent was selected and the sufficient adsorption was achieved via vibrating at room temperature for 20 min. For luteoloside in prediction set, the correlation coefficient between the reference concentration and the predicted concentration was 0.9765 after the NIR spectral data were processed with continuous wavelet transform. The recovery was 84.7%-113.2% in the concentration range of 0.15-19.5 mg/L. The results indicated that the preconcentration strategy with benzoboric acid adsorbent was successfully developed, and the determination was sensitive and selective for luteoloside by means of the combination of adsorption-preconcentration and NIR diffuse reflectance spectroscopy. The strategy could be recommended for the determination of other effective constituents in medicine plants.
Benzoboric acid adsorbent was prepared tenderly for adsorption of trace luteoloside from Coreopsis tinctoria. Without desorption, the enriched samples were detected directly by near-infrared (NIR) diffuse reflectance spectroscopy method. To predict its content, a quantitative correction model for luteoloside was established by partial least square regression method. The results illustrated that the adsorption efficiency was 85.5% when 0.2 g of benzoboric acid adsorbent was selected and the sufficient adsorption was achieved via vibrating at room temperature for 20 min. For luteoloside in prediction set, the correlation coefficient between the reference concentration and the predicted concentration was 0.9765 after the NIR spectral data were processed with continuous wavelet transform. The recovery was 84.7%-113.2% in the concentration range of 0.15-19.5 mg/L. The results indicated that the preconcentration strategy with benzoboric acid adsorbent was successfully developed, and the determination was sensitive and selective for luteoloside by means of the combination of adsorption-preconcentration and NIR diffuse reflectance spectroscopy. The strategy could be recommended for the determination of other effective constituents in medicine plants.
2020, 48(4): 543-550
doi: 10.19756/j.issn.0253-3820.191627
Abstract:
A method for rapid determination of the content of fipronil in the solid preparation of acetamiprid based on attenuated total reflection Fourier transform infrared spectroscopy (ATR-FT-IR) was developed. Fourier transform infrared spectrometer was used to collect the spectra of 69 solid samples and their extraction samples. The effects of different pretreatment methods and variable selection methods on the spectra of the samples were explored. The sample set was divided by the Kennard-Stone algorithm. A quantitative model was established and optimized by partial least squares. Separate validation sets were used to evaluate the models. The predicted regression coefficient of the fipronil quantitative model of solid samples was 0.9762, and the root mean square error of prediction set (RMSEP) was 0.0022. The predicted regression coefficient of the fipronil quantitative model of dimethylformamide (DMF) extraction was 0.9810, and the RMSEP was 0.0019. When the fipronil contents were 0.60%-5.00%, the predicted mean relative error (MRE) of the external test sample was 0.08. This method can be applied to the rapid detection of banned pesticides in addition to fipronil.
A method for rapid determination of the content of fipronil in the solid preparation of acetamiprid based on attenuated total reflection Fourier transform infrared spectroscopy (ATR-FT-IR) was developed. Fourier transform infrared spectrometer was used to collect the spectra of 69 solid samples and their extraction samples. The effects of different pretreatment methods and variable selection methods on the spectra of the samples were explored. The sample set was divided by the Kennard-Stone algorithm. A quantitative model was established and optimized by partial least squares. Separate validation sets were used to evaluate the models. The predicted regression coefficient of the fipronil quantitative model of solid samples was 0.9762, and the root mean square error of prediction set (RMSEP) was 0.0022. The predicted regression coefficient of the fipronil quantitative model of dimethylformamide (DMF) extraction was 0.9810, and the RMSEP was 0.0019. When the fipronil contents were 0.60%-5.00%, the predicted mean relative error (MRE) of the external test sample was 0.08. This method can be applied to the rapid detection of banned pesticides in addition to fipronil.
2020, 48(4): 551-558
doi: 10.19756/j.issn.0253-3820.191458
Abstract:
Based on proton nuclear magnetic resonance (1H NMR) technique and partial least squares-discriminant analysis (PLS-DA), the accelerated oxidation characteristics of coix seed oil at room temperature and 60℃ were monitored. The results showed that when the fresh coix seed oil sample was stored at room temperature for 135 days, the linoleic acid content of the oil sample decreased by 16.46%, the oleic acid increased by 1.83%, and the saturated fatty acid increased by 30.23%, but the primary and secondary oxidation product signal peaks were not observed. When the coix seed oil was accelerated at 60℃ for 18 d, the secondary oxidation product signal peak appeared. After accelerated 42 d, the linoleic acid content decreased by 71.99%, the oleic acid increased by 7.33%, and the saturated fatty acid content increased by 1.34 times, indicating that the content of fatty acids varied significantly at different oxidation temperatures (p<0.05), the oxidation order satisfied polyunsaturated fatty acid (PUFA)>monounsaturated fatty acid (MUSA)>saturated fatty acid (SFA). The deterioration of accelerated oxidized oil samples is faster than that of room temperature oxidized oil samples. The PLS-DA model could identify the oxidation conditions of coix seed oil. Therefore, the qualitative analysis model constructed by 1H NMR fingerprint combined with multivariate statistical analysis could classify and identify the quality changes of oil oxidation accurately, which could support the reference on quality control and quality evaluation of coix seed oil.
Based on proton nuclear magnetic resonance (1H NMR) technique and partial least squares-discriminant analysis (PLS-DA), the accelerated oxidation characteristics of coix seed oil at room temperature and 60℃ were monitored. The results showed that when the fresh coix seed oil sample was stored at room temperature for 135 days, the linoleic acid content of the oil sample decreased by 16.46%, the oleic acid increased by 1.83%, and the saturated fatty acid increased by 30.23%, but the primary and secondary oxidation product signal peaks were not observed. When the coix seed oil was accelerated at 60℃ for 18 d, the secondary oxidation product signal peak appeared. After accelerated 42 d, the linoleic acid content decreased by 71.99%, the oleic acid increased by 7.33%, and the saturated fatty acid content increased by 1.34 times, indicating that the content of fatty acids varied significantly at different oxidation temperatures (p<0.05), the oxidation order satisfied polyunsaturated fatty acid (PUFA)>monounsaturated fatty acid (MUSA)>saturated fatty acid (SFA). The deterioration of accelerated oxidized oil samples is faster than that of room temperature oxidized oil samples. The PLS-DA model could identify the oxidation conditions of coix seed oil. Therefore, the qualitative analysis model constructed by 1H NMR fingerprint combined with multivariate statistical analysis could classify and identify the quality changes of oil oxidation accurately, which could support the reference on quality control and quality evaluation of coix seed oil.
