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2022 Volume 50 Issue 9
2022, 50(9): 1279-1288
doi: 10.19756/j.issn.0253-3820.221004
Abstract:
Sample preparation methods determine the sensitivity and quantitative accuracy of proteomics analysis, especially for mass-limited proteomics sample. Traditional preparation methods of proteomic sample, such as in-solution digestion and filter aided sample preparation (FASP) method, generally require large amount of starting materials due to the significant sample loss, and thus is not suitable for the qualitative and quantitative analysis of mass-limited samples, such as small number of subcellular cells, biopsy samples, single cells, et al. To overcome this problem, it is urgent to develop sample preparation methods for microgram or even nanogram of starting materials. This paper reviewed various mass-limited sample preparation methods that based on different mechanisms, such as in-StageTip, single-pot solid-phase-enhanced sample preparation (SP3), integrated proteome analysis device (iPAD), simple and integrated spintip-based proteomics technology (SISPROT), fully automated sample treatment (FAST), miniaturized filter-aided sample preparation (MICROFASP) and so on. The development trends in the future were also envisioned.
Sample preparation methods determine the sensitivity and quantitative accuracy of proteomics analysis, especially for mass-limited proteomics sample. Traditional preparation methods of proteomic sample, such as in-solution digestion and filter aided sample preparation (FASP) method, generally require large amount of starting materials due to the significant sample loss, and thus is not suitable for the qualitative and quantitative analysis of mass-limited samples, such as small number of subcellular cells, biopsy samples, single cells, et al. To overcome this problem, it is urgent to develop sample preparation methods for microgram or even nanogram of starting materials. This paper reviewed various mass-limited sample preparation methods that based on different mechanisms, such as in-StageTip, single-pot solid-phase-enhanced sample preparation (SP3), integrated proteome analysis device (iPAD), simple and integrated spintip-based proteomics technology (SISPROT), fully automated sample treatment (FAST), miniaturized filter-aided sample preparation (MICROFASP) and so on. The development trends in the future were also envisioned.
2022, 50(9): 1289-1298
doi: 10.19756/j.issn.0253-3820.221157
Abstract:
The green sample pretreatment technique has been one of the research hotspots in the analysis of complex matrix samples. Although solvent-free extraction of volatile organic compounds in samples can be implemented by headspace solid-phase microextraction (HS-SPME), it is difficult to achieve satisfactory results for complex matrix samples. Cooling-assisted solid phase microextraction (CA-SPME) allows for heating sample matrix and cooling coating simultaneously, which overcomes the drawbacks of regular HS-SPME, and effectively promotes the extraction efficiency for volatile and semi-volatile compounds in complex matrix samples. Thus, the solvent-free sample analysis in complex matrix can be accomplished by CA-SPME. Given its unique advantages, CA-SPME provides a new approach for green sample analysis from complex matrix. Therefore, the recent advances of CA-SPME were introduced in this review, including the studies in CA-SPME devices, the factors affecting extraction efficiency, and the applications of CA-SPME. Finally, the future trends and prospective were also discussed. This review aimed to provide a valuable reference for research in complex sample analysis.
The green sample pretreatment technique has been one of the research hotspots in the analysis of complex matrix samples. Although solvent-free extraction of volatile organic compounds in samples can be implemented by headspace solid-phase microextraction (HS-SPME), it is difficult to achieve satisfactory results for complex matrix samples. Cooling-assisted solid phase microextraction (CA-SPME) allows for heating sample matrix and cooling coating simultaneously, which overcomes the drawbacks of regular HS-SPME, and effectively promotes the extraction efficiency for volatile and semi-volatile compounds in complex matrix samples. Thus, the solvent-free sample analysis in complex matrix can be accomplished by CA-SPME. Given its unique advantages, CA-SPME provides a new approach for green sample analysis from complex matrix. Therefore, the recent advances of CA-SPME were introduced in this review, including the studies in CA-SPME devices, the factors affecting extraction efficiency, and the applications of CA-SPME. Finally, the future trends and prospective were also discussed. This review aimed to provide a valuable reference for research in complex sample analysis.
2022, 50(9): 1299-1307
doi: 10.19756/j.issn.0253-3820.221249
Abstract:
A fluorescence resonance energy transfer (FRET) immunoassay based on upconversion nanoparticles (UCNP) and gold nanorods (GNR) was constructed for sensitive detection of carcinoembryonic antigen (CEA). UCNP was employed as the donor and GNR was employed as the acceptor. The CEA antibody was covalently attached on the surface of UCNP and GNR to form UCNP-cAb and GNR-dAb conjugates, respectively. After introduction of CEA, a "sandwich" complex was formed through the antigen-antibody specific interaction, which resulted in the close proximity of UCNP and GNR to generate FRET. And the fluorescence quenching efficiency was positively correlated with the concentration of CEA. The constructed FRET immunoassay realized the detection of CEA in both buffer solution and human serum samples with a limit of detection (S/N=3) of 0.01 ng/mL, a linear range from 0.01 ng/mL to 100 ng/mL and good selectivity. It was expected that this FRET immunoassay could be further used in clinical applications and provided new methods for early diagnosis, treatment and prognosis monitoring of related cancers.
A fluorescence resonance energy transfer (FRET) immunoassay based on upconversion nanoparticles (UCNP) and gold nanorods (GNR) was constructed for sensitive detection of carcinoembryonic antigen (CEA). UCNP was employed as the donor and GNR was employed as the acceptor. The CEA antibody was covalently attached on the surface of UCNP and GNR to form UCNP-cAb and GNR-dAb conjugates, respectively. After introduction of CEA, a "sandwich" complex was formed through the antigen-antibody specific interaction, which resulted in the close proximity of UCNP and GNR to generate FRET. And the fluorescence quenching efficiency was positively correlated with the concentration of CEA. The constructed FRET immunoassay realized the detection of CEA in both buffer solution and human serum samples with a limit of detection (S/N=3) of 0.01 ng/mL, a linear range from 0.01 ng/mL to 100 ng/mL and good selectivity. It was expected that this FRET immunoassay could be further used in clinical applications and provided new methods for early diagnosis, treatment and prognosis monitoring of related cancers.
2022, 50(9): 1308-1318
doi: 10.19756/j.issn.0253-3820.221024
Abstract:
Tetrahedral DNA nanomaterial (TDN) is a simple and strong pyramidal three-dimensional structure model. It has the advantages such as superior mechanical properties, stable structure, simple synthesis method, high synthesis yield, and unique specific recognition performance. In this work, a TDN-based electrochemical sensing platform was constructed for highly sensitive detection of DNA. By using Fe-metal organic framework (Fe-MOF) as signal probe, the detection did not require acid treatment and pretreatment process, which could save detection time. In addition, Fe-MOF was easy to functionalize. After the surface was loaded with precious metal nanoparticles, it was easy to modify nucleic acid or protein molecules, which could simplify the modification process. By using graphene-nano-gold particle composite materials with excellent performance as the substrate, it could further improve the sensitivity. When the target DNA was present, the purpose of detecting DNA was achieved by detecting the signal peak in the Fe-MOF material. In the concentration range of 0.01-140 pmol/L, the linear equation was I=2.858 × lgc(pmol/L)+6.488 (R2=0.9935), and the detection limit (3σ) was 4.5 fmol/L.
Tetrahedral DNA nanomaterial (TDN) is a simple and strong pyramidal three-dimensional structure model. It has the advantages such as superior mechanical properties, stable structure, simple synthesis method, high synthesis yield, and unique specific recognition performance. In this work, a TDN-based electrochemical sensing platform was constructed for highly sensitive detection of DNA. By using Fe-metal organic framework (Fe-MOF) as signal probe, the detection did not require acid treatment and pretreatment process, which could save detection time. In addition, Fe-MOF was easy to functionalize. After the surface was loaded with precious metal nanoparticles, it was easy to modify nucleic acid or protein molecules, which could simplify the modification process. By using graphene-nano-gold particle composite materials with excellent performance as the substrate, it could further improve the sensitivity. When the target DNA was present, the purpose of detecting DNA was achieved by detecting the signal peak in the Fe-MOF material. In the concentration range of 0.01-140 pmol/L, the linear equation was I=2.858 × lgc(pmol/L)+6.488 (R2=0.9935), and the detection limit (3σ) was 4.5 fmol/L.
2022, 50(9): 1319-1327
doi: 10.19756/j.issn.0253-3820.221099
Abstract:
The cerium vanadate (CeVO4)-based nanozyme was synthesized through a hydrothermal synthesis method with arginine as the stabilizer. Due to the change of stabilizer, the ratio of CeⅢ to CeⅣ in CeVO4 changed and thus allowed that the nanozyme showed nanoparticle morphology, which was different from that of nanorod prepared with EDTA as stabilizer. In the reaction system of 3,3',5,5'-tetramethylbenzidine (TMB) and hydrogen peroxide (H2O2), the CeVO4-based nanozyme first catalyzed H2O2 to produce hydroxyl radical (·OH), which could oxidize TMB and thus resulted in a colour change of solution from colourless to blue, proving that CeVO4 prepared with arginine had strong peroxidase-like activity and the generation of ·OH accounted for the outstanding peroxidase-like properties. Based on these features, a colorimetric method was developed for detecting H2O2, glucose and antioxidants. This study not only provided a new direction for the research of CeVO4-based nanozyme, but also developed a fast and simple method for total antioxidant capacity (TAC) assay.
The cerium vanadate (CeVO4)-based nanozyme was synthesized through a hydrothermal synthesis method with arginine as the stabilizer. Due to the change of stabilizer, the ratio of CeⅢ to CeⅣ in CeVO4 changed and thus allowed that the nanozyme showed nanoparticle morphology, which was different from that of nanorod prepared with EDTA as stabilizer. In the reaction system of 3,3',5,5'-tetramethylbenzidine (TMB) and hydrogen peroxide (H2O2), the CeVO4-based nanozyme first catalyzed H2O2 to produce hydroxyl radical (·OH), which could oxidize TMB and thus resulted in a colour change of solution from colourless to blue, proving that CeVO4 prepared with arginine had strong peroxidase-like activity and the generation of ·OH accounted for the outstanding peroxidase-like properties. Based on these features, a colorimetric method was developed for detecting H2O2, glucose and antioxidants. This study not only provided a new direction for the research of CeVO4-based nanozyme, but also developed a fast and simple method for total antioxidant capacity (TAC) assay.
2022, 50(9): 1328-1335
doi: 10.19756/j.issn.0253-3820.221080
Abstract:
Helicobacter pylori (Hp), which has proven to be a class I carcinogen of gastric cancer, can cause various gastrointestinal diseases including stomach and duodenum. The carbon-13 urea breath test (13C-UBT) is considered to be the chief choice for the initial diagnosis and confirmation of Hp infection due to its advantages such as accuracy, simplicity, non-radioactivity, and non-invasiveness. However, 13C-UBT remains to be an expensive method for detecting Hp infection owing to the high cost of testing equipment and the limited global production of 13C urea. To realize the real-time detection of Hp with high sensitivity and low cost by 13C-UBT, this study explored the feasibility of exploiting high-resolution and high-sensitivity mid-infrared quantum cascade laser spectroscopy to replace the traditional detection instruments based on mass spectrometry and near-infrared spectroscopy as Hp detection instruments. The Hp infection-positive, negative, and treated subjects were included, and the influences of sampling methods (mouth and nose) and 13C urea dosages (5, 10, 20, and 75 mg) on the diagnosis of Hp infection were investigated. The results showed that the mid-infrared quantum cascade laser spectroscopy possessed the characteristics of real-time in-situ measurement and high levels of accuracy, and the maximum measurement error was about 0.1‰-0.3‰. The results of the breath sampling methods indicated that the measured values obtained from the sampling methods of mouth and nose kept consistent (p>0.05), proving that nose air would be highly desirable as an alternative to mouth air to reduce the interference of oral flora on detection results when collecting breath samples for Hp detection. The test results of different dosages demonstrated that accurate diagnosis results could be obtained by administrating 5 mg of 13C urea, and the reagent costs could be crucially saved when compared with the current clinical 13C urea dose (75-100 mg). In conclusion, this study examined the measurement accuracy of the infrared spectrum instrument based on the quantum cascade lasers, investigated its feasibility for detecting Hp infection of the breath diagnosis, as well as optimized the breath sampling methods and suitable 13C urea dosages, which provided necessary experimental basis for subsequent mass samples detection.
Helicobacter pylori (Hp), which has proven to be a class I carcinogen of gastric cancer, can cause various gastrointestinal diseases including stomach and duodenum. The carbon-13 urea breath test (13C-UBT) is considered to be the chief choice for the initial diagnosis and confirmation of Hp infection due to its advantages such as accuracy, simplicity, non-radioactivity, and non-invasiveness. However, 13C-UBT remains to be an expensive method for detecting Hp infection owing to the high cost of testing equipment and the limited global production of 13C urea. To realize the real-time detection of Hp with high sensitivity and low cost by 13C-UBT, this study explored the feasibility of exploiting high-resolution and high-sensitivity mid-infrared quantum cascade laser spectroscopy to replace the traditional detection instruments based on mass spectrometry and near-infrared spectroscopy as Hp detection instruments. The Hp infection-positive, negative, and treated subjects were included, and the influences of sampling methods (mouth and nose) and 13C urea dosages (5, 10, 20, and 75 mg) on the diagnosis of Hp infection were investigated. The results showed that the mid-infrared quantum cascade laser spectroscopy possessed the characteristics of real-time in-situ measurement and high levels of accuracy, and the maximum measurement error was about 0.1‰-0.3‰. The results of the breath sampling methods indicated that the measured values obtained from the sampling methods of mouth and nose kept consistent (p>0.05), proving that nose air would be highly desirable as an alternative to mouth air to reduce the interference of oral flora on detection results when collecting breath samples for Hp detection. The test results of different dosages demonstrated that accurate diagnosis results could be obtained by administrating 5 mg of 13C urea, and the reagent costs could be crucially saved when compared with the current clinical 13C urea dose (75-100 mg). In conclusion, this study examined the measurement accuracy of the infrared spectrum instrument based on the quantum cascade lasers, investigated its feasibility for detecting Hp infection of the breath diagnosis, as well as optimized the breath sampling methods and suitable 13C urea dosages, which provided necessary experimental basis for subsequent mass samples detection.
2022, 50(9): 1336-1344
doi: 10.19756/j.issn.0253-3820.221127
Abstract:
A novel ratiometric fluorescent paper chip was constructed using dual fluorescent dyes based on fluorescence resonance energy transfer (FRET) between donor Cy3 and acceptor Cy5. The Cy3-labeled aptamer and Cy5-labeled auxiliary DNA (aDNA) were simultaneously combined with the complementary DNA (cDNA) pre-modified on the surface of paper chip to form a specific double stranded structure. After forming double stranded structure, a ratiometric fluorescence signal change was realized by FRET between donor Cy3 and acceptor Cy5. In this case, the fluorescence intensity of Cy3 decreased accompanied by the increasing of the fluorescence intensity of Cy5. In the presence of ochratoxin A (OTA), the specific binding of aptamer toward OTA led to Cy3-labeled aptamer detaching from the double stranded structure, which resulted in an increasing distance between Cy3 and Cy5. Therefore, the fluorescence intensity of Cy3 increased while the fluorescence intensity of Cy5 decreased. The fluorescence response ratio values (F567/F669:the fluorescence intensity of Cy3 at 567 nm to the fluorescence intensity of Cy5 at 669 nm) exhibited a good linear response with OTA concentration in the range of 10-300 nmol/L and the detection limit was 5.6 nmol/L. The designed ratiometric fluorescent paper chip was applied to detect OTA in spiked peanut and red wine samples, and the recoveries were 92.7%-107.6%. This sensor provided an efficient and convenient method for detection of mycotoxin in food.
A novel ratiometric fluorescent paper chip was constructed using dual fluorescent dyes based on fluorescence resonance energy transfer (FRET) between donor Cy3 and acceptor Cy5. The Cy3-labeled aptamer and Cy5-labeled auxiliary DNA (aDNA) were simultaneously combined with the complementary DNA (cDNA) pre-modified on the surface of paper chip to form a specific double stranded structure. After forming double stranded structure, a ratiometric fluorescence signal change was realized by FRET between donor Cy3 and acceptor Cy5. In this case, the fluorescence intensity of Cy3 decreased accompanied by the increasing of the fluorescence intensity of Cy5. In the presence of ochratoxin A (OTA), the specific binding of aptamer toward OTA led to Cy3-labeled aptamer detaching from the double stranded structure, which resulted in an increasing distance between Cy3 and Cy5. Therefore, the fluorescence intensity of Cy3 increased while the fluorescence intensity of Cy5 decreased. The fluorescence response ratio values (F567/F669:the fluorescence intensity of Cy3 at 567 nm to the fluorescence intensity of Cy5 at 669 nm) exhibited a good linear response with OTA concentration in the range of 10-300 nmol/L and the detection limit was 5.6 nmol/L. The designed ratiometric fluorescent paper chip was applied to detect OTA in spiked peanut and red wine samples, and the recoveries were 92.7%-107.6%. This sensor provided an efficient and convenient method for detection of mycotoxin in food.
2022, 50(9): 1345-1354
doi: 10.19756/j.issn.0253-3820.210868
Abstract:
To realize simple, rapid, in-situ, non-destructive analysis and identification of compounds on thin-layer chromatography, a combined technology of thin-layer chromatography with carbon fiber ionization mass spectrometry (TLC-CFI-MS) was developed, and the application of this technique in the field of Chinese medicine analysis was studied. First, to meet the needs of different types of samples or different analysis scenarios, two analysis modes of solvent-assisted TLC-CFI-MS and heat-assisted TLC-CFI-MS were designed. Then, the application of the above two analysis methods in analysis of traditional Chinese medicine was studied, and the analytical performance of the two analytical methods was examined. The limit of detection (LOD) of coumarin by solvent-assisted TLC-CFI-MS was 8 μg/mL, and the limit of quantification (LOQ) was 30 μg/mL; LOD and LOQ of heat-assisted TLC-CFI-MS were 20 ng/mL and 50 ng/mL, respectively. The heat-assisted TLC-CFI-MS demonstrated the quantitative analysis capability for coumarin in the concentration range of 0.01-1 mg/mL (R2=0.997). In addition, the application of solvent-assisted TLC-CFI-MS and heat-assisted TLC-CFI-MS in the analysis of traditional Chinese medicines was preliminarily explored. Both methods achieved rapid in-situ identification of compounds on chromatographic plates after TLC analysis of Cinnamomum cassia and Ligusticum chuanxiong. For example, coumarin and cinnamic aldehyde from Cinnamomum cassia and ligustilide, snidium lactone and ligustride A from Ligusticum chuanxiong were all identified. In addition, the coumarin content in a cinnamon sample was determined to be 1.04 mg/g by heat-assisted TLC-CFI-MS. The results suggested that TLC-CFI-MS had certain application potential in the rapid analysis of traditional Chinese medicine compounds. It would also show certain application value in the analysis of traditional Chinese medicine components, as well as quality control and evaluation.
To realize simple, rapid, in-situ, non-destructive analysis and identification of compounds on thin-layer chromatography, a combined technology of thin-layer chromatography with carbon fiber ionization mass spectrometry (TLC-CFI-MS) was developed, and the application of this technique in the field of Chinese medicine analysis was studied. First, to meet the needs of different types of samples or different analysis scenarios, two analysis modes of solvent-assisted TLC-CFI-MS and heat-assisted TLC-CFI-MS were designed. Then, the application of the above two analysis methods in analysis of traditional Chinese medicine was studied, and the analytical performance of the two analytical methods was examined. The limit of detection (LOD) of coumarin by solvent-assisted TLC-CFI-MS was 8 μg/mL, and the limit of quantification (LOQ) was 30 μg/mL; LOD and LOQ of heat-assisted TLC-CFI-MS were 20 ng/mL and 50 ng/mL, respectively. The heat-assisted TLC-CFI-MS demonstrated the quantitative analysis capability for coumarin in the concentration range of 0.01-1 mg/mL (R2=0.997). In addition, the application of solvent-assisted TLC-CFI-MS and heat-assisted TLC-CFI-MS in the analysis of traditional Chinese medicines was preliminarily explored. Both methods achieved rapid in-situ identification of compounds on chromatographic plates after TLC analysis of Cinnamomum cassia and Ligusticum chuanxiong. For example, coumarin and cinnamic aldehyde from Cinnamomum cassia and ligustilide, snidium lactone and ligustride A from Ligusticum chuanxiong were all identified. In addition, the coumarin content in a cinnamon sample was determined to be 1.04 mg/g by heat-assisted TLC-CFI-MS. The results suggested that TLC-CFI-MS had certain application potential in the rapid analysis of traditional Chinese medicine compounds. It would also show certain application value in the analysis of traditional Chinese medicine components, as well as quality control and evaluation.
2022, 50(9): 1355-1363
doi: 10.19756/j.issn.0253-3820.221191
Abstract:
Based on silver-enhanced gold nanoparticles (AuNPs) label technique that AuNPs could specifically catalyze the deposition of silver ions using hydroquin as a weak reducing agent, an efficient and sensitive electrochemical aptasensor was developed for detection of trace okadaic acid (OA). When the sample solution containing OA, the OA aptamer dissociated from the dsDNA on electrode surface due to the specific binding between OA and OA aptamer, AuNPs labeled signal probe (Sp) could hybridize with the resulted free capture probe (Cp) on the electrode surface. And then, the electrode was immersed in a silver staining reagent to perform following sliver staining. Finally, the oxidation signal of the nano-silver was directly detected by square wave voltammetry (SWV). Under the optimal experimental conditions, the linear range of the established OA aptasensor was 10.0 pg/mL-500.0 ng/mL, and the detection limit (3σ/k) was 8.8 pg/mL. The sensor was applied to detection of mussels. The experimental results showed that the content of OA in the edible part of mussels was 36.0 ng/g, which was lower than the permitted maximal limit of European Union (160.0 ng/g), and the recoveries were 94.2%-112.0%.
Based on silver-enhanced gold nanoparticles (AuNPs) label technique that AuNPs could specifically catalyze the deposition of silver ions using hydroquin as a weak reducing agent, an efficient and sensitive electrochemical aptasensor was developed for detection of trace okadaic acid (OA). When the sample solution containing OA, the OA aptamer dissociated from the dsDNA on electrode surface due to the specific binding between OA and OA aptamer, AuNPs labeled signal probe (Sp) could hybridize with the resulted free capture probe (Cp) on the electrode surface. And then, the electrode was immersed in a silver staining reagent to perform following sliver staining. Finally, the oxidation signal of the nano-silver was directly detected by square wave voltammetry (SWV). Under the optimal experimental conditions, the linear range of the established OA aptasensor was 10.0 pg/mL-500.0 ng/mL, and the detection limit (3σ/k) was 8.8 pg/mL. The sensor was applied to detection of mussels. The experimental results showed that the content of OA in the edible part of mussels was 36.0 ng/g, which was lower than the permitted maximal limit of European Union (160.0 ng/g), and the recoveries were 94.2%-112.0%.
2022, 50(9): 1364-1372
doi: 10.19756/j.issn.0253-3820.221012
Abstract:
The widely used paracetamol (acetaminophen, APAP) for antipyretic and analgesic promoting enrichment on the cell membrane surface by means of hydrogen bonds is very important. In this work, 3-mercaptopropionic acid self-assembled monolayer (MPA SAM) containing hydrogen acceptors (negatively charged carboxylates) on the surface was used as simplified model to simulate the cell membrane surface. The enrichment of APAP promoted by hydrogen bonds on the surface of simulated cell membranes was studied by scanning electrochemical microscopy (SECM). The experimental results showed that with the increase of Mg2+ concentration or pH value, the carboxyl groups of MPA SAM dissociated and shifted positively to produce more carboxylates (hydrogen acceptors). The enrichment of APAP on the surface of MPA SAM was promoted. Furthermore, SECM image mode realized the visualization of enrichment. This work might provide a certain reference for understanding the enrichment of APAP promoted by hydrogen bonds on the surface of simulated cell membrane and the design of APAP sensors.
The widely used paracetamol (acetaminophen, APAP) for antipyretic and analgesic promoting enrichment on the cell membrane surface by means of hydrogen bonds is very important. In this work, 3-mercaptopropionic acid self-assembled monolayer (MPA SAM) containing hydrogen acceptors (negatively charged carboxylates) on the surface was used as simplified model to simulate the cell membrane surface. The enrichment of APAP promoted by hydrogen bonds on the surface of simulated cell membranes was studied by scanning electrochemical microscopy (SECM). The experimental results showed that with the increase of Mg2+ concentration or pH value, the carboxyl groups of MPA SAM dissociated and shifted positively to produce more carboxylates (hydrogen acceptors). The enrichment of APAP on the surface of MPA SAM was promoted. Furthermore, SECM image mode realized the visualization of enrichment. This work might provide a certain reference for understanding the enrichment of APAP promoted by hydrogen bonds on the surface of simulated cell membrane and the design of APAP sensors.
2022, 50(9): 1373-1383
doi: 10.19756/j.issn.0253-3820.221053
Abstract:
A non-target screening method based on ultra-high performance liquid chromatography-quadrupole-orbitrap high resolution mass spectrometry (UHPLC-Q-Orbitrap HRMS) was established for screening and identification of plastic additives in plastic products. Chromatographic separation was performed on a Hypersil GOLD C18 chromatographic column. The MS data were obtained under MS/dd-MS2 scan mode with electrospray ionization source (HESI) in both positive and negative ion modes. A MS data base including 31 kinds of plastic additives and a suspect list including more than 6028 kinds of plastic additives were established. The non-target screen workflow including UHPLC-HRMS method, MS data analysis and compound identification were optimized. According to the matching level of precursor ion (MS), fragment ions (MS2) and retention time (RT) with data bases and/or silico fragment, the compounds screened here could be categorized based on confidence levels from L1 to L4. A total of 1944 compounds in the extract of PVC sheath of cords were screened and identified by the developed non-target screening method, among which 4 compounds including diethyl phthalate (DEP), bis(2-ethylhexyl) phthalate (DEHP), tris(2-chloroethyl) phosphate (TCEP) and bisphenol A (BPA) were identified as L1 confidence, 88 and 50 compounds were identified as L2 and L3 confidence (phthalates, amides, alkenoic acids, etc.). This method was further applied to primary investigation of plastic additives released from typical plastic products under the artificial biodigestive system. A total of 132 kinds of additives were identified. L1 compounds included DEHP, BPA, drometrizole (UVP) and triethyl phosphate (TEP), with release amount of 4.6 mg/g, 38.1 μg/g, 47.8 ng/g and 158.2 ng/g, respectively.
A non-target screening method based on ultra-high performance liquid chromatography-quadrupole-orbitrap high resolution mass spectrometry (UHPLC-Q-Orbitrap HRMS) was established for screening and identification of plastic additives in plastic products. Chromatographic separation was performed on a Hypersil GOLD C18 chromatographic column. The MS data were obtained under MS/dd-MS2 scan mode with electrospray ionization source (HESI) in both positive and negative ion modes. A MS data base including 31 kinds of plastic additives and a suspect list including more than 6028 kinds of plastic additives were established. The non-target screen workflow including UHPLC-HRMS method, MS data analysis and compound identification were optimized. According to the matching level of precursor ion (MS), fragment ions (MS2) and retention time (RT) with data bases and/or silico fragment, the compounds screened here could be categorized based on confidence levels from L1 to L4. A total of 1944 compounds in the extract of PVC sheath of cords were screened and identified by the developed non-target screening method, among which 4 compounds including diethyl phthalate (DEP), bis(2-ethylhexyl) phthalate (DEHP), tris(2-chloroethyl) phosphate (TCEP) and bisphenol A (BPA) were identified as L1 confidence, 88 and 50 compounds were identified as L2 and L3 confidence (phthalates, amides, alkenoic acids, etc.). This method was further applied to primary investigation of plastic additives released from typical plastic products under the artificial biodigestive system. A total of 132 kinds of additives were identified. L1 compounds included DEHP, BPA, drometrizole (UVP) and triethyl phosphate (TEP), with release amount of 4.6 mg/g, 38.1 μg/g, 47.8 ng/g and 158.2 ng/g, respectively.
2022, 50(9): 1384-1390
doi: 10.19756/j.issn.0253-3820.221100
Abstract:
Rare earth pollution in soil affects plant growth and accumulates in animals and humans through the food chain, and causes serious environmental and human health issues. To take effective measures to control the rare earth pollution, it is necessary to detect the content of rare earth elements in soil. Laser-induced breakdown spectroscopy (LIBS) has many advantages including in-situ, non-destructive, real-time and multi-element simultaneous analysis for solid samples such as soil. However, the sensitivity of this technique is low, which limits its application in the quantitative analysis of trace elements. In this work, a new method utilizing the combination of atmospheric pressure glow discharge (APGD) and cylindrical confinement (CC) was proposed to improve the detection sensitivity of laser-induced breakdown spectroscopy, which was applied to determination of Y, La, Eu, Yb and Lu rare earth elements in soil. The results showed that the detection sensitivity of LIBS for Y, La, Eu, Yb and Lu were enhanced by 11.6, 9.3, 7.9, 8.2 and 7.6 times by APGD and CC, respectively. To verify the accuracy of the proposed system, it was applied to the detection of soil certified reference materials and an unknown soil sample, and the relative errors between the detection values of this work and those of ICP-OES were 1.5%-8.6% and 1.8%-7.0%, respectively.
Rare earth pollution in soil affects plant growth and accumulates in animals and humans through the food chain, and causes serious environmental and human health issues. To take effective measures to control the rare earth pollution, it is necessary to detect the content of rare earth elements in soil. Laser-induced breakdown spectroscopy (LIBS) has many advantages including in-situ, non-destructive, real-time and multi-element simultaneous analysis for solid samples such as soil. However, the sensitivity of this technique is low, which limits its application in the quantitative analysis of trace elements. In this work, a new method utilizing the combination of atmospheric pressure glow discharge (APGD) and cylindrical confinement (CC) was proposed to improve the detection sensitivity of laser-induced breakdown spectroscopy, which was applied to determination of Y, La, Eu, Yb and Lu rare earth elements in soil. The results showed that the detection sensitivity of LIBS for Y, La, Eu, Yb and Lu were enhanced by 11.6, 9.3, 7.9, 8.2 and 7.6 times by APGD and CC, respectively. To verify the accuracy of the proposed system, it was applied to the detection of soil certified reference materials and an unknown soil sample, and the relative errors between the detection values of this work and those of ICP-OES were 1.5%-8.6% and 1.8%-7.0%, respectively.
2022, 50(9): 1391-1398
doi: 10.19756/j.issn.0253-3820.211236
Abstract:
Near-infrared (NIR) spectroscopy is a highly efficient and non-destructive technology applied in many areas. The measured spectra, however, are susceptible to shift due to various external interferences, resulting in biased analytical results. Time-shifts in NIR spectra are typical phenomena of continuously shifting spectra with measuring time, which is common in practical applications. In this study,a new method for modeling the time-shift NIR spectra was proposed, in which the shifting signal was divided into shifting background and sample-dependent shifts, and then corrected by continuous wavelet transform (CWT) and semi-supervised parameter-free calibration enhancement (SS-PFCE), respectively. The efficiency of the method was evaluated by modeling 1941 time-shift NIR spectra of soil samples collected in Yunnan Province (China) in 2019 and 2020 to predict the soil organic matter (SOM) content. The spectra taken in 2019 were calibrated (Root mean squared error of prediction (RMSEP)=6.7 g/kg, R2=0.76) and a large deviation was observed in predicting the spectra taken in 2020 (RMSEP=31.3 g/kg, R2=0.50). After CWT treatment, the prediction of spectra measured in 2020 was significantly promoted by predicting the spectra (RMSEP=11.6 g/kg, R2=0.66), and the prediction was further improved by SS-PFCE (RMSEP=8.3 g/kg, R2=0.67). The results indicated that CWT and SS-PFCE were efficient for eliminating the shifting background and sample-related shifts in time-shift NIR spectra, respectively.
Near-infrared (NIR) spectroscopy is a highly efficient and non-destructive technology applied in many areas. The measured spectra, however, are susceptible to shift due to various external interferences, resulting in biased analytical results. Time-shifts in NIR spectra are typical phenomena of continuously shifting spectra with measuring time, which is common in practical applications. In this study,a new method for modeling the time-shift NIR spectra was proposed, in which the shifting signal was divided into shifting background and sample-dependent shifts, and then corrected by continuous wavelet transform (CWT) and semi-supervised parameter-free calibration enhancement (SS-PFCE), respectively. The efficiency of the method was evaluated by modeling 1941 time-shift NIR spectra of soil samples collected in Yunnan Province (China) in 2019 and 2020 to predict the soil organic matter (SOM) content. The spectra taken in 2019 were calibrated (Root mean squared error of prediction (RMSEP)=6.7 g/kg, R2=0.76) and a large deviation was observed in predicting the spectra taken in 2020 (RMSEP=31.3 g/kg, R2=0.50). After CWT treatment, the prediction of spectra measured in 2020 was significantly promoted by predicting the spectra (RMSEP=11.6 g/kg, R2=0.66), and the prediction was further improved by SS-PFCE (RMSEP=8.3 g/kg, R2=0.67). The results indicated that CWT and SS-PFCE were efficient for eliminating the shifting background and sample-related shifts in time-shift NIR spectra, respectively.
2022, 50(9): 1399-1406
doi: 10.19756/j.issn.0253-3820.221197
Abstract:
A metal-ceramic heater (MCH) was used for the first time as a solid direct sampling electrothermal vaporizer (ETV), and a new mercury analyzer was thus fabricated by combining MCH-ETV with an atomic fluorescence spectrometer (AFS). The instrumental conditions, such as vaporization power, atomizer flame, working gas flow rate, etc., were optimized, and a direct solid sampling analysis method for Hg in soil was thereby established without sample digestion. Under the optimal conditions, the detection limit (LOD) of Hg was 0.16 ng/g with sample size of 50 mg, and the regression coefficient (R2) was 0.996 in the linear range of 8-590 ng/g. The Hg values of three soil certified reference materials (CRMs) measured by this method were within their ranges of the certified values; further, the Hg values of the nine real soil samples were consistent with the results by the standard method, and the recoveries were 96%-107%, proving favorable analytical accuracy. Moreover, the relative standard deviations (RSDs) of repeated measurements for real soil samples ranged from 2% to 11%, indicating acceptable analytical precision. Due to canceling gold amalgamation, the whole analysis time of this method was less than 3 min. As well, the MCH-ETV power consumption was below 200 W with a small size, which was thereby suitable for the miniaturization of commercialized mercury analyzer in the future.
A metal-ceramic heater (MCH) was used for the first time as a solid direct sampling electrothermal vaporizer (ETV), and a new mercury analyzer was thus fabricated by combining MCH-ETV with an atomic fluorescence spectrometer (AFS). The instrumental conditions, such as vaporization power, atomizer flame, working gas flow rate, etc., were optimized, and a direct solid sampling analysis method for Hg in soil was thereby established without sample digestion. Under the optimal conditions, the detection limit (LOD) of Hg was 0.16 ng/g with sample size of 50 mg, and the regression coefficient (R2) was 0.996 in the linear range of 8-590 ng/g. The Hg values of three soil certified reference materials (CRMs) measured by this method were within their ranges of the certified values; further, the Hg values of the nine real soil samples were consistent with the results by the standard method, and the recoveries were 96%-107%, proving favorable analytical accuracy. Moreover, the relative standard deviations (RSDs) of repeated measurements for real soil samples ranged from 2% to 11%, indicating acceptable analytical precision. Due to canceling gold amalgamation, the whole analysis time of this method was less than 3 min. As well, the MCH-ETV power consumption was below 200 W with a small size, which was thereby suitable for the miniaturization of commercialized mercury analyzer in the future.
2022, 50(9): 1407-1414
doi: 10.19756/j.issn.0253-3820.210721
Abstract:
The gilt brass nail components embedded in the Buddhist pagoda were coated with a special layer of dark red material which was discovered during the protection and restoration process. After pre-treatments with methanol/acid extraction, liquid chromatography-mass spectrometry (LC-MS) in combination with energy dispersive X-ray fluorescence (EDXRF), X-ray powder diffraction (XRD) and micro-Fourier transform infrared (micro-FTIR) was applied to analysis of the composition and manufacturing process. The results showed that the black layer consisted of gypsum, quartz and calcite, as well as atacamite, nantokite and weddellite as corrosion products with plant gum as effect additive. Red sandalwood was applied as coloring matter for dyeing to echo the whole style of pagoda naturally. This study provided a new view for the analysis of mix-media cultural relics.
The gilt brass nail components embedded in the Buddhist pagoda were coated with a special layer of dark red material which was discovered during the protection and restoration process. After pre-treatments with methanol/acid extraction, liquid chromatography-mass spectrometry (LC-MS) in combination with energy dispersive X-ray fluorescence (EDXRF), X-ray powder diffraction (XRD) and micro-Fourier transform infrared (micro-FTIR) was applied to analysis of the composition and manufacturing process. The results showed that the black layer consisted of gypsum, quartz and calcite, as well as atacamite, nantokite and weddellite as corrosion products with plant gum as effect additive. Red sandalwood was applied as coloring matter for dyeing to echo the whole style of pagoda naturally. This study provided a new view for the analysis of mix-media cultural relics.
2022, 50(9): 1415-1424
doi: 10.19756/j.issn.0253-3820.221001
Abstract:
Hemoglobin is an important physiological index of human body. Abnormal concentration of hemoglobin will lead to various diseases. Near infrared spectroscopy can be use to detect hemoglobin content in human body quickly and without reagent. However, the infrared spectrum overlaps seriously, the effective information is low, and it is vulnerable to external noise. Therefore, it is usually necessary to divide and pretreat the spectral data, and then establish quantitative model, so as to remove the adverse effects of interference information on the prediction model. But how to choose the best partition method and the best partition proportion and how to choose the best pretreatment methods are still problems. To solve these issues, by taking the spectral data of 190 blood samples with different concentrations of hemoglobin and 150 imitation solution samples with different concentrations of hemoglobin as the research object, partial least squares (PLS) model predictability with different dataset partitioning methods including equal interval division method, kennard stone(K_S), sample set partitioning based on joint X-Y distances method (SPXY) and duplex algorithm (Duplex) under 41 different partitioning proportions were studied in this work. Pretreatments including wavelet transform (WT), standard normal variable (SNV), direct orthogonal signal correction (DOSC), and S_G (savitzky Golay) first-order derivation form 65 pretreatment combinations (considering order), and the influence of these 65 pretreatment combinations on the prediction accuracy of PLS quantitative analysis model were studied. Experimental results indicated that the optimal dataset partitioning method of PLS model of the two datasets was SPXY method, in which the optimal division proportion of blood sample was 0.48, and the optimal division proportion of imitation solution was 0.90. Among the 65 pretreatment methods, the best pretreatment combination of blood samples was S_G1+WT, in which the correlation coefficient of prediction set (Rp) was 0.9808, and the root mean square error of prediction set (RMSEP) was 0.2701. The best pretreatment combination of imitation solution samples was SNV+WT, in which the Rp was 0.9952 and the RMSEP was 3.8154. The superposition of two algorithms showed better denoising effect. The research results provided an idea and method for the processing of this kind of spectral data.
Hemoglobin is an important physiological index of human body. Abnormal concentration of hemoglobin will lead to various diseases. Near infrared spectroscopy can be use to detect hemoglobin content in human body quickly and without reagent. However, the infrared spectrum overlaps seriously, the effective information is low, and it is vulnerable to external noise. Therefore, it is usually necessary to divide and pretreat the spectral data, and then establish quantitative model, so as to remove the adverse effects of interference information on the prediction model. But how to choose the best partition method and the best partition proportion and how to choose the best pretreatment methods are still problems. To solve these issues, by taking the spectral data of 190 blood samples with different concentrations of hemoglobin and 150 imitation solution samples with different concentrations of hemoglobin as the research object, partial least squares (PLS) model predictability with different dataset partitioning methods including equal interval division method, kennard stone(K_S), sample set partitioning based on joint X-Y distances method (SPXY) and duplex algorithm (Duplex) under 41 different partitioning proportions were studied in this work. Pretreatments including wavelet transform (WT), standard normal variable (SNV), direct orthogonal signal correction (DOSC), and S_G (savitzky Golay) first-order derivation form 65 pretreatment combinations (considering order), and the influence of these 65 pretreatment combinations on the prediction accuracy of PLS quantitative analysis model were studied. Experimental results indicated that the optimal dataset partitioning method of PLS model of the two datasets was SPXY method, in which the optimal division proportion of blood sample was 0.48, and the optimal division proportion of imitation solution was 0.90. Among the 65 pretreatment methods, the best pretreatment combination of blood samples was S_G1+WT, in which the correlation coefficient of prediction set (Rp) was 0.9808, and the root mean square error of prediction set (RMSEP) was 0.2701. The best pretreatment combination of imitation solution samples was SNV+WT, in which the Rp was 0.9952 and the RMSEP was 3.8154. The superposition of two algorithms showed better denoising effect. The research results provided an idea and method for the processing of this kind of spectral data.
2022, 50(9): 1425-1434
doi: 10.19756/j.issn.0253-3820.210838
Abstract:
The optical emission spectroscopy (OES) from atmospheric pressure microwave (MW) plasma was proposed for detection of trace toxic agents, such as phosphorus and chlorine. Characteristic OES of dimethyl methylphosphonate (DMMP), malathion and chloroform, as simulant of phosphorus and chlorine toxics, was analyzed and identified. The characteristic OES of DMMP included P atomic lines (213.62 and 214.91 nm), PO radical bands (254.04 and 255.50 nm), and C atomic line (247.86 nm). The characteristic OES of malathion was the same as that of DMMP, but their relative intensity was different, which could be used to discriminate the two chemicals. The characteristic OES of chloroform included Cl atoms (725.66, 754.71, 837.59, 858.60 and 894.81 nm, etc). By taking the characteristic OES of DMMP as an example, the OES intensity had a linear relationship with the MW power within the range of 40-110 W. As for the impact of OES collection region, OES intensity of the object to be detected at the head of the MW plasma was the highest, and those at the middle and tail were reduced in turn. With a MW power of 70 W and collection region from plasma head, the detection limit of DMMP, malathion and chloroform were 0.05, 3.3 and 1.8 mg/m3, respectively. This work presented an atomic/molecular OES detection method using MW plasma and proposed that the relative OES intensity strategy could be used to discriminate chemicals with same characteristic OES, which provided a technical reference for detection of trace toxic agents.
The optical emission spectroscopy (OES) from atmospheric pressure microwave (MW) plasma was proposed for detection of trace toxic agents, such as phosphorus and chlorine. Characteristic OES of dimethyl methylphosphonate (DMMP), malathion and chloroform, as simulant of phosphorus and chlorine toxics, was analyzed and identified. The characteristic OES of DMMP included P atomic lines (213.62 and 214.91 nm), PO radical bands (254.04 and 255.50 nm), and C atomic line (247.86 nm). The characteristic OES of malathion was the same as that of DMMP, but their relative intensity was different, which could be used to discriminate the two chemicals. The characteristic OES of chloroform included Cl atoms (725.66, 754.71, 837.59, 858.60 and 894.81 nm, etc). By taking the characteristic OES of DMMP as an example, the OES intensity had a linear relationship with the MW power within the range of 40-110 W. As for the impact of OES collection region, OES intensity of the object to be detected at the head of the MW plasma was the highest, and those at the middle and tail were reduced in turn. With a MW power of 70 W and collection region from plasma head, the detection limit of DMMP, malathion and chloroform were 0.05, 3.3 and 1.8 mg/m3, respectively. This work presented an atomic/molecular OES detection method using MW plasma and proposed that the relative OES intensity strategy could be used to discriminate chemicals with same characteristic OES, which provided a technical reference for detection of trace toxic agents.
