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2021 Volume 49 Issue 2
2021, 49(2): 159-171
doi: 10.19756/j.issn.0253-3820.201410
Abstract:
Intelligent wearable devices have many characteristics, including convenience, intelligence and real-time. Through the detection and analysis by wearable devices, and the real-time transmission of data, it can test vital signs and movement and other important information, monitor the human body, and provide data support for health status. According to the development of wearable devices in recent years, this article summarizes the different ways to wear wearable devices, the common materials for wearable devices and the different sensing modes of wearable devices. Then its applications in physiological and motion detection is presented. Finally, the challenges and opportunities faced by the wearable devices are analyzed and prospected.
Intelligent wearable devices have many characteristics, including convenience, intelligence and real-time. Through the detection and analysis by wearable devices, and the real-time transmission of data, it can test vital signs and movement and other important information, monitor the human body, and provide data support for health status. According to the development of wearable devices in recent years, this article summarizes the different ways to wear wearable devices, the common materials for wearable devices and the different sensing modes of wearable devices. Then its applications in physiological and motion detection is presented. Finally, the challenges and opportunities faced by the wearable devices are analyzed and prospected.
2021, 49(2): 172-183
doi: 10.19756/j.issn.0253-3820.201450
Abstract:
The rapid and accurate detection method for bisphenol A (BPA) is of great significance for protection of human health. Aptamer-based biosensors, which integrates biology, chemistry, physics and nanotechnology into a coherent whole, are novel and efficient and have great potential in the field of BPA detection. Based on a brief analysis of BPA aptamers, the detection principles of several aptamer biosensors and their lastest application for BPA detection were introduced in this review. Also the future development trend of aptamer-based biosensor was prospected.
The rapid and accurate detection method for bisphenol A (BPA) is of great significance for protection of human health. Aptamer-based biosensors, which integrates biology, chemistry, physics and nanotechnology into a coherent whole, are novel and efficient and have great potential in the field of BPA detection. Based on a brief analysis of BPA aptamers, the detection principles of several aptamer biosensors and their lastest application for BPA detection were introduced in this review. Also the future development trend of aptamer-based biosensor was prospected.
2021, 49(2): 184-196
doi: 10.19756/j.issn.0253-3820.201512
Abstract:
Fluorescent probes can achieve rapid detection of analytes, and have become a research hotspot in recent years due to their excellent selectivity, high sensitivity and easy operation. Excited state intramolecular proton transfer (ESIPT) is one of the most basic strategies for designing fluorescence probes. Fluorescent probes based on ESIPT possess large Stokes shift, strong luminescence and high fluorescence quantum yield. However, there are still some disadvantages, such as sensitivity to the environment and short emission wavelength. In recent years, the combination of ESIPT with other fluorescence mechanisms has obtained new fluorescent probes with dual mechanism of fluorescence response. This strategy can not only solve the shortage of ESIPT fluorophore, but also realize multi-fluorescence signal channel, and significantly improves the selectivity and sensitivity of the new probe. In this review, we mainly analyze the detection mechanism and imaging application of fluorescence probes of photoinduced electron transfer (PET)-ESIPT, intramolecular charge transfer (ICT)-ESIPT, fluorescence resonance energy transfer (FRET)-ESIPT, aggregation-induced emission (AIE)-ESIPT for ions, small molecules, biological macromolecules in recent years.
Fluorescent probes can achieve rapid detection of analytes, and have become a research hotspot in recent years due to their excellent selectivity, high sensitivity and easy operation. Excited state intramolecular proton transfer (ESIPT) is one of the most basic strategies for designing fluorescence probes. Fluorescent probes based on ESIPT possess large Stokes shift, strong luminescence and high fluorescence quantum yield. However, there are still some disadvantages, such as sensitivity to the environment and short emission wavelength. In recent years, the combination of ESIPT with other fluorescence mechanisms has obtained new fluorescent probes with dual mechanism of fluorescence response. This strategy can not only solve the shortage of ESIPT fluorophore, but also realize multi-fluorescence signal channel, and significantly improves the selectivity and sensitivity of the new probe. In this review, we mainly analyze the detection mechanism and imaging application of fluorescence probes of photoinduced electron transfer (PET)-ESIPT, intramolecular charge transfer (ICT)-ESIPT, fluorescence resonance energy transfer (FRET)-ESIPT, aggregation-induced emission (AIE)-ESIPT for ions, small molecules, biological macromolecules in recent years.
2021, 49(2): 197-206
doi: 10.19756/j.issn.0253-3820.201566
Abstract:
Staphylococcus aureus (S.aureus) contamination is an important factor affecting food quality and safety. Therefore, it is urgent to develop a quick and easy on-site analysis method for detecting S.aureus in food. In this work, inactivated S.aureus was used to immunize specific pathogen free (SPF) hens, and the yolk antibody (IgY) was purified from the eggs wich could efficiently and specifically capture S.aureus. IgY modified on the surface of the screen-printed electrode could be used for the selective separation and enrichment of S.aureus in the sample. Ferrocene (Fc) and phenylboronic acid (BPA) were covalently connected on the surface of UiO-66 nano-metal organic framework material (MOF) to obtain a MOF@Fc-BPA composite probe. The prepared probe and the IgY on the electrode jointly identified and captured S.aureus, and then generated a redox signal of Fc on the electrode. Under the optimal reaction conditions, the electrochemical signal intensity was proportional to the logarithm of the S.aureus concentration, the detection range was 10-109 cfu/mL, the detection limit was 3 cfu/mL, and the detection time was 20 min only. In addition, we used this sensor to detect S.aureus in cultured shrimp, and the results obtained were consistent with that of standard ELISA, while the detection time was greatly shortened, and the detection limit was two orders of magnitude lower than the ELISA method. The results indicated that the immunosensor was able to quickly screen S.aureus on site.
Staphylococcus aureus (S.aureus) contamination is an important factor affecting food quality and safety. Therefore, it is urgent to develop a quick and easy on-site analysis method for detecting S.aureus in food. In this work, inactivated S.aureus was used to immunize specific pathogen free (SPF) hens, and the yolk antibody (IgY) was purified from the eggs wich could efficiently and specifically capture S.aureus. IgY modified on the surface of the screen-printed electrode could be used for the selective separation and enrichment of S.aureus in the sample. Ferrocene (Fc) and phenylboronic acid (BPA) were covalently connected on the surface of UiO-66 nano-metal organic framework material (MOF) to obtain a MOF@Fc-BPA composite probe. The prepared probe and the IgY on the electrode jointly identified and captured S.aureus, and then generated a redox signal of Fc on the electrode. Under the optimal reaction conditions, the electrochemical signal intensity was proportional to the logarithm of the S.aureus concentration, the detection range was 10-109 cfu/mL, the detection limit was 3 cfu/mL, and the detection time was 20 min only. In addition, we used this sensor to detect S.aureus in cultured shrimp, and the results obtained were consistent with that of standard ELISA, while the detection time was greatly shortened, and the detection limit was two orders of magnitude lower than the ELISA method. The results indicated that the immunosensor was able to quickly screen S.aureus on site.
2021, 49(2): 207-215
doi: 10.19756/j.issn.0253-3820.201483
Abstract:
Electrospun nanofibers (NFs) with good moisture-resistance were prepared by electrospinning technology, and further assembled with CdTe quantum dots (CdTe QDs). The results of scanning electron microscopy, transmission electron microscopy and confocal fluorescence microscopy showed that the CdTe QDs with strong fluorescence were uniformly assembled on the electrospun NFs after the electrostatic adsorption for 90 min at pH 7.2. Under 365 nm excitation, the CdTe QDs-electrospun NFs assembly presented red fluorescence, which could be significantly quenched by copper ion (Cu2+), and the fluorescence quenching degree of CdTe QDs electrospun NFs assembly showed a good linear relationship with concentration of Cu2+ in the concentration range of 0.08-800 μmol/L, and the detection limit was 11.1 nmol/L (S/N=3). This method had advantages of simplicity and high selectivity, and was successfully applied to the visualization and portable detection of copper ions in environmental water samples.
Electrospun nanofibers (NFs) with good moisture-resistance were prepared by electrospinning technology, and further assembled with CdTe quantum dots (CdTe QDs). The results of scanning electron microscopy, transmission electron microscopy and confocal fluorescence microscopy showed that the CdTe QDs with strong fluorescence were uniformly assembled on the electrospun NFs after the electrostatic adsorption for 90 min at pH 7.2. Under 365 nm excitation, the CdTe QDs-electrospun NFs assembly presented red fluorescence, which could be significantly quenched by copper ion (Cu2+), and the fluorescence quenching degree of CdTe QDs electrospun NFs assembly showed a good linear relationship with concentration of Cu2+ in the concentration range of 0.08-800 μmol/L, and the detection limit was 11.1 nmol/L (S/N=3). This method had advantages of simplicity and high selectivity, and was successfully applied to the visualization and portable detection of copper ions in environmental water samples.
2021, 49(2): 216-225
doi: 10.19756/j.issn.0253-3820.201298
Abstract:
A method for selective separation and highly sensitive quantitation of dual-target miRNAs as disease biomarkers by duplex specific nuclease (DSN)-enabled signal amplification strategy combined with high-performance liquid chromatography (HPLC) was developed. The enzyme-based isothermal amplification strategy enhanced the signals of the target miRNAs and solved the problem of low sensitivity during the detection of nucleic acids utilizing conventional HPLC. To obtain an effective separation of the signals of different miRNAs, DNA probes which were immobilized on magnetic beads were designed with different lengths and base sequences. Effective magnetic separation minimized the background noise and expanded the dynamic range. Consequently, the assay achieved a detection limit of 0.33 fmol/L for miRNA-155 and 0.24 fmol/L for miRNA-21, respectively. The proposed assay was successfully applied to detection of miRNA-155 and miRNA-21 in serum samples from lupus erythematosus, cervical cancer and ovarian cancer patients. The results obtained here were comparable to those obtained by quantitative real-time polymerase chain reaction.
A method for selective separation and highly sensitive quantitation of dual-target miRNAs as disease biomarkers by duplex specific nuclease (DSN)-enabled signal amplification strategy combined with high-performance liquid chromatography (HPLC) was developed. The enzyme-based isothermal amplification strategy enhanced the signals of the target miRNAs and solved the problem of low sensitivity during the detection of nucleic acids utilizing conventional HPLC. To obtain an effective separation of the signals of different miRNAs, DNA probes which were immobilized on magnetic beads were designed with different lengths and base sequences. Effective magnetic separation minimized the background noise and expanded the dynamic range. Consequently, the assay achieved a detection limit of 0.33 fmol/L for miRNA-155 and 0.24 fmol/L for miRNA-21, respectively. The proposed assay was successfully applied to detection of miRNA-155 and miRNA-21 in serum samples from lupus erythematosus, cervical cancer and ovarian cancer patients. The results obtained here were comparable to those obtained by quantitative real-time polymerase chain reaction.
2021, 49(2): 226-236
doi: 10.19756/j.issn.0253-3820.201438
Abstract:
A self-powered DNA machine was constructed by loading DNAzyme strand and dye-labelled substrate strand co-modified gold nanoparticles (AuNPs) on MnO2 nanosheets via van der Waals force. When acetylcholinesterase (AChE) converted its substrate, acetylthiocholine (ATCh), into thiocholine (TCh), the MnO2 nanosheets were degraded into Mn2+. The Mn2+ dependent-DNAzyme was triggered and plenty of dye-labelled fragments were released from the surface of AuNPs, which would lead to the enhancement of fluorescence. When AChE was inhibited by organophosphorus pesticides (OPs), the DNA machine could not be activated. This self-powered DNA machine was characterized by transmission electron microscopy (TEM), ultraviolet-visible absorption spectroscopy, zeta potential, dynamic light scattering (DLS) and X-ray photoelectron spectroscopy (XPS), and the performance of DNA machine was optimized. Under the optimal conditions, the proposed DNA machine was applied to the determination of dichlorvos (DDVP) with a linear range of 5-500 μg/L and a limit of detection of 3.62 μg/L (3σ). The method presented here was applied to the recovery assay of DDVP in spiked lettuce. The recoveries for DDVP were 96.5%-104.2%, and the relative standard deviations (RSD) were 1.7%-7.5%.
A self-powered DNA machine was constructed by loading DNAzyme strand and dye-labelled substrate strand co-modified gold nanoparticles (AuNPs) on MnO2 nanosheets via van der Waals force. When acetylcholinesterase (AChE) converted its substrate, acetylthiocholine (ATCh), into thiocholine (TCh), the MnO2 nanosheets were degraded into Mn2+. The Mn2+ dependent-DNAzyme was triggered and plenty of dye-labelled fragments were released from the surface of AuNPs, which would lead to the enhancement of fluorescence. When AChE was inhibited by organophosphorus pesticides (OPs), the DNA machine could not be activated. This self-powered DNA machine was characterized by transmission electron microscopy (TEM), ultraviolet-visible absorption spectroscopy, zeta potential, dynamic light scattering (DLS) and X-ray photoelectron spectroscopy (XPS), and the performance of DNA machine was optimized. Under the optimal conditions, the proposed DNA machine was applied to the determination of dichlorvos (DDVP) with a linear range of 5-500 μg/L and a limit of detection of 3.62 μg/L (3σ). The method presented here was applied to the recovery assay of DDVP in spiked lettuce. The recoveries for DDVP were 96.5%-104.2%, and the relative standard deviations (RSD) were 1.7%-7.5%.
2021, 49(2): 237-245
doi: 10.19756/j.issn.0253-3820.201647
Abstract:
An activated carboxyl-based approach for latent fingerprint development with high quality and high efficiency was proposed. Firstly, carboxyl-functionalized fluorescent europium nanocomplex was chemically synthesized via a one-step process by using europium （Ⅲ） ion as the luminescence center, phthalic acid as the first ligand, and phenanthroline as the second ligand. Then, the micromorphology, crystal structure, ultraviolet absorption property, fluorescent emission performance, surface functional groups and thermal property of these synthesized europium nanocomplex were characterized by transmission electron microscopy, powder X-ray diffractometer, ultraviolet-visible spectrophotometer, fluorescence spectrophotometer, Fourier transform infrared spectrometer and simultaneous thermal analyzer, respectively. The carboxyl groups on the surface of europium nanocomplex were further activated using 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride combined with N-hydroxysuccinimide. The activated carboxyl groups on the surface of europium nanocomplex could easily react with the amino groups in latent fingerprint through amide reaction, and the latent fingerprint was thus fluorescently developed with high efficiency. The mechanism of latent fingerprint development based on activated carboxyl process was discussed in detail, and the nanocomplex dosage and the staining time in developing suspension were also systematically optimized. In addition, the effects in fingerprint development were investigated from three aspects including contrast, sensitivity and selectivity. Experimental results showed that, the activated carboxyl-based approach could achieve a high performance in latent fingerprint development, exhibiting high efficiency, good operability and wide applicability.
An activated carboxyl-based approach for latent fingerprint development with high quality and high efficiency was proposed. Firstly, carboxyl-functionalized fluorescent europium nanocomplex was chemically synthesized via a one-step process by using europium （Ⅲ） ion as the luminescence center, phthalic acid as the first ligand, and phenanthroline as the second ligand. Then, the micromorphology, crystal structure, ultraviolet absorption property, fluorescent emission performance, surface functional groups and thermal property of these synthesized europium nanocomplex were characterized by transmission electron microscopy, powder X-ray diffractometer, ultraviolet-visible spectrophotometer, fluorescence spectrophotometer, Fourier transform infrared spectrometer and simultaneous thermal analyzer, respectively. The carboxyl groups on the surface of europium nanocomplex were further activated using 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride combined with N-hydroxysuccinimide. The activated carboxyl groups on the surface of europium nanocomplex could easily react with the amino groups in latent fingerprint through amide reaction, and the latent fingerprint was thus fluorescently developed with high efficiency. The mechanism of latent fingerprint development based on activated carboxyl process was discussed in detail, and the nanocomplex dosage and the staining time in developing suspension were also systematically optimized. In addition, the effects in fingerprint development were investigated from three aspects including contrast, sensitivity and selectivity. Experimental results showed that, the activated carboxyl-based approach could achieve a high performance in latent fingerprint development, exhibiting high efficiency, good operability and wide applicability.
2021, 49(2): 246-252
doi: 10.19756/j.issn.0253-3820.201404
Abstract:
The interferences of gold, sodium, potassium and calcium are serious in the determination of lithium tantalate by conventional quadrupole inductively coupled plasma mass spectrometry (ICP-QMS), especially for gold. In this study, the methods for determination of gold, sodium, potassium and calcium in lithium tantalate by inductively coupled plasma tandem mass spectrometry (ICP-MS/MS) were developed. The reaction principles were studied and the determination parameters were optimized. 133Cs was selected as internal standard to compensate matrix effect. Au could be detected at m/z=197 under on-mass mode with 0.9 mL/min O2 as reaction gas, or detected at m/z=231 as Au(NH3)2+ cluster ion under mass-shift mode with 6.5 mL/min NH3/He mixture as reaction gas. There was no significant difference between the detection results of Na under O2 or NH3 on-mass mode, which verified that the interference of LiO was negligible. The detection limits of Au, Na, K and Ca were 0.006-0.11 μg/g. The relative standard deviations (RSDs, n=7) of sample detection results were less than 10%, and the recoveries were 86.3%-106.5%.
The interferences of gold, sodium, potassium and calcium are serious in the determination of lithium tantalate by conventional quadrupole inductively coupled plasma mass spectrometry (ICP-QMS), especially for gold. In this study, the methods for determination of gold, sodium, potassium and calcium in lithium tantalate by inductively coupled plasma tandem mass spectrometry (ICP-MS/MS) were developed. The reaction principles were studied and the determination parameters were optimized. 133Cs was selected as internal standard to compensate matrix effect. Au could be detected at m/z=197 under on-mass mode with 0.9 mL/min O2 as reaction gas, or detected at m/z=231 as Au(NH3)2+ cluster ion under mass-shift mode with 6.5 mL/min NH3/He mixture as reaction gas. There was no significant difference between the detection results of Na under O2 or NH3 on-mass mode, which verified that the interference of LiO was negligible. The detection limits of Au, Na, K and Ca were 0.006-0.11 μg/g. The relative standard deviations (RSDs, n=7) of sample detection results were less than 10%, and the recoveries were 86.3%-106.5%.
2021, 49(2): 253-262
doi: 10.19756/j.issn.0253-3820.201479
Abstract:
A novel method for rapid determination of 17O anomaly in atmospheric aerosol samples was developed. With this method, the measurement was completed in 15 min with higher analytical precision and lower detection limit. This method required a minimum of 0.4 μg N for achieving an analytical precision of 0.6‰, and 0.8 μg N was selected in this work. The nitrate in atmospheric aerosol samples was converted to nitrous oxide by optimized bacterial denitrification process within 4 h. After that a thermal decomposition of nitrous oxide in sample gas was carried out in a gold tube at 800℃ after separation and purification, followed by gas chromatographic separation and isotope analysis of oxygen. The experiment result showed that the analytical precision of Δ17O by this method could reach 0.19‰ at a sample content of 0.8 μg N, and δ15N could reach 0.15‰ at same time. This method was not only suitable for determination17O anomaly in atmospheric aerosol samples, but also for the other atmospheric environmental samples such as rain and snow samples with low concentrations.
A novel method for rapid determination of 17O anomaly in atmospheric aerosol samples was developed. With this method, the measurement was completed in 15 min with higher analytical precision and lower detection limit. This method required a minimum of 0.4 μg N for achieving an analytical precision of 0.6‰, and 0.8 μg N was selected in this work. The nitrate in atmospheric aerosol samples was converted to nitrous oxide by optimized bacterial denitrification process within 4 h. After that a thermal decomposition of nitrous oxide in sample gas was carried out in a gold tube at 800℃ after separation and purification, followed by gas chromatographic separation and isotope analysis of oxygen. The experiment result showed that the analytical precision of Δ17O by this method could reach 0.19‰ at a sample content of 0.8 μg N, and δ15N could reach 0.15‰ at same time. This method was not only suitable for determination17O anomaly in atmospheric aerosol samples, but also for the other atmospheric environmental samples such as rain and snow samples with low concentrations.
2021, 49(2): 263-270
doi: 10.19756/j.issn.0253-3820.201271
Abstract:
A simple and sensitive cotton thread-based rapid visual DNA analysis method was developed. In this method, the reporter probe was constructed by using hairpin structure DNA sequence to modify carbon nanotube/gold nanoparticles nanocomposite (CNT/GNPs) for the first time. The DNA probe had 8 adenosines at both end, the middle part sequence of it was able to match with target DNA sequence quite well, and a biotin and thiol group were modified at 3' and 5' end respectively. The hairpin structure was formed due to the interaction between adenosines and coralyne. In the presence of target DNA molecules in sample, the hairpin structure of DNA on nanocomposite probe would be opened and the biotin group at 3' end of DNA sequence would be released and combined with streptavidin pre-immobilized on the test zone of cotton thread, forming a deep color band for visual detection of target DNA. Under the optimal conditions, the response of device was linear in the DNA concentration range of 1-100 nmol/L, and the detection limit was estimated to be 0.44 nmol/L. The sensitivity of the method was improved evidently comparing with the previous method of using gold nanoparticle probe. The biosensor also had strong ability to discriminate single base mutation, which realized rapid visual test of DNA sequence related to Hereditary tyrosinemia.
A simple and sensitive cotton thread-based rapid visual DNA analysis method was developed. In this method, the reporter probe was constructed by using hairpin structure DNA sequence to modify carbon nanotube/gold nanoparticles nanocomposite (CNT/GNPs) for the first time. The DNA probe had 8 adenosines at both end, the middle part sequence of it was able to match with target DNA sequence quite well, and a biotin and thiol group were modified at 3' and 5' end respectively. The hairpin structure was formed due to the interaction between adenosines and coralyne. In the presence of target DNA molecules in sample, the hairpin structure of DNA on nanocomposite probe would be opened and the biotin group at 3' end of DNA sequence would be released and combined with streptavidin pre-immobilized on the test zone of cotton thread, forming a deep color band for visual detection of target DNA. Under the optimal conditions, the response of device was linear in the DNA concentration range of 1-100 nmol/L, and the detection limit was estimated to be 0.44 nmol/L. The sensitivity of the method was improved evidently comparing with the previous method of using gold nanoparticle probe. The biosensor also had strong ability to discriminate single base mutation, which realized rapid visual test of DNA sequence related to Hereditary tyrosinemia.
2021, 49(2): 271-281
doi: 10.19756/j.issn.0253-3820.201563
Abstract:
Single particle inductively coupled plasma-mass spectrometry (spICP-MS) was used to study the release behavior of silver from silver nanotextiles, and the effect of extraction and dilution on the release was systematically investigated. The results showed that the silver nanotextiles coild released both silver nanoparticles and silver ions synchronously, but the release behavior in sweat simulant and water was significantly different. The AgNPs released in sweat simulant were larger in size, higher in silver ions concentration than those in water, and the amount of the released silver ions increased with time. More meaningfully, when the extraction solution was diluted with different multiple, the detected AgNPs showed different sizes, where the difference between the larger and small ones could reach several times, and gradually decreased with the increase of the dilution times until the particle size did not decrease further, which was believed to be caused by the depolymerization of particle aggregates during the extraction process. The size of the smallest particles measured by spICP-MS was similar to that measured by SEM. This study showed that the sample preparation and test conditions (including sampling, extraction liquid, dilution etc.) had a significant impact on the results measured by spICP-MS. Therefore, it was necessary to develop a standardized sample release detection and analysis process to ensure the accuracy and consistency of the results. The lower detection limits for particles size and particles concentration of the silver nanoparticles obtained by this method were 16 nm and 2.06×106 particle/L, respectively. While the lower detection limit for Ag+ concentration was 0.003 μg/L. The spiked recoveries of the number concentration of AgNPs and the Ag+ concentration were 98.7% and 105.8% in sweat stimulant, and 98.9% and 101.7% in water, respectively.
Single particle inductively coupled plasma-mass spectrometry (spICP-MS) was used to study the release behavior of silver from silver nanotextiles, and the effect of extraction and dilution on the release was systematically investigated. The results showed that the silver nanotextiles coild released both silver nanoparticles and silver ions synchronously, but the release behavior in sweat simulant and water was significantly different. The AgNPs released in sweat simulant were larger in size, higher in silver ions concentration than those in water, and the amount of the released silver ions increased with time. More meaningfully, when the extraction solution was diluted with different multiple, the detected AgNPs showed different sizes, where the difference between the larger and small ones could reach several times, and gradually decreased with the increase of the dilution times until the particle size did not decrease further, which was believed to be caused by the depolymerization of particle aggregates during the extraction process. The size of the smallest particles measured by spICP-MS was similar to that measured by SEM. This study showed that the sample preparation and test conditions (including sampling, extraction liquid, dilution etc.) had a significant impact on the results measured by spICP-MS. Therefore, it was necessary to develop a standardized sample release detection and analysis process to ensure the accuracy and consistency of the results. The lower detection limits for particles size and particles concentration of the silver nanoparticles obtained by this method were 16 nm and 2.06×106 particle/L, respectively. While the lower detection limit for Ag+ concentration was 0.003 μg/L. The spiked recoveries of the number concentration of AgNPs and the Ag+ concentration were 98.7% and 105.8% in sweat stimulant, and 98.9% and 101.7% in water, respectively.
2021, 49(2): 282-291
doi: 10.19756/j.issn.0253-3820.201595
Abstract:
Phytosterol biomarkers in marine sediments are often used to indicate the source of the sedimentary organics in the ocean, and to reflect the evolution of marine ecosystem and environment. In this study, a novel method for simultaneous determination of common phytosterols in marine sediments by non-aqueous reversed-phase liquid chromatography-atmospheric pressure photoionization mass spectrometry (LC-APPI-MS) was established. First, the APPI-MS characteristics of phytosterols were clarified. Under the positive APPI mode, phytosterols tended to produce stable characteristic ion peaks such as[M+H-H2O]+,[M+H-H2]+ and[M+H-2H2]+. In the process of APPI-MS2, abundant fragment ion peaks were produced mainly through i-heterolysis. Second, LC-APPI-MS conditions were optimized, and a reversed-phase C18 column was used to separate phytosterols with pure methanol as mobile phase and toluene as APPI ionization dopant, which could realize high sensitivity of detection for phytosterols in sediments. Furthermore, the method showed strong matrix interference resistance ability, good linear relationship (R2 ≥ 0.9990), high recovery rate (86.4%-94.9%) and good repeatability (RSDs ≤ 8.3%). Finally, the proposed method was applied to detect common phytosterols in the surface sediment of Laizhou Bay in China, and several sterols, such as brassicasterol, fucosterol and sitosterol, etc., were detected in every sediment sample. The total concentration of sterols was 4.21-12.91 μg/g, among which the concentration of sitosterol was the highest. To sum up, the developed LC-APPI-MS method was a powerful tool for determination of common phytosterols in marine sediments, with easy-operation and high sensitivity.
Phytosterol biomarkers in marine sediments are often used to indicate the source of the sedimentary organics in the ocean, and to reflect the evolution of marine ecosystem and environment. In this study, a novel method for simultaneous determination of common phytosterols in marine sediments by non-aqueous reversed-phase liquid chromatography-atmospheric pressure photoionization mass spectrometry (LC-APPI-MS) was established. First, the APPI-MS characteristics of phytosterols were clarified. Under the positive APPI mode, phytosterols tended to produce stable characteristic ion peaks such as[M+H-H2O]+,[M+H-H2]+ and[M+H-2H2]+. In the process of APPI-MS2, abundant fragment ion peaks were produced mainly through i-heterolysis. Second, LC-APPI-MS conditions were optimized, and a reversed-phase C18 column was used to separate phytosterols with pure methanol as mobile phase and toluene as APPI ionization dopant, which could realize high sensitivity of detection for phytosterols in sediments. Furthermore, the method showed strong matrix interference resistance ability, good linear relationship (R2 ≥ 0.9990), high recovery rate (86.4%-94.9%) and good repeatability (RSDs ≤ 8.3%). Finally, the proposed method was applied to detect common phytosterols in the surface sediment of Laizhou Bay in China, and several sterols, such as brassicasterol, fucosterol and sitosterol, etc., were detected in every sediment sample. The total concentration of sterols was 4.21-12.91 μg/g, among which the concentration of sitosterol was the highest. To sum up, the developed LC-APPI-MS method was a powerful tool for determination of common phytosterols in marine sediments, with easy-operation and high sensitivity.
2021, 49(2): 292-300
doi: 10.19756/j.issn.0253-3820.191717
Abstract:
This work studied on La element, which hosted in the Sedimentary rare earth deposits of the Permian Xuanwei Formation, Northwest Guizhou Province. Based on the study of rare earth soil spectroscopy, the hyperspectral quantitative estimation and inversion of La element were carried out under GA-ELM model. After a variety of spectral transformations (S-G smoothing, differential, reciprocal, continuum removal), the accuracy differences of the mathematical models established by two methods of selecting characteristic variables (Pearson correlation coefficient and variable importance assessment (CARS, SPA, RF)) were studied and compared. The results showed that there was a non-linear relationship between the content of La in mineral samples and the spectral reflectance. Different spectral transformation methods had different ability to extract the information of La content in soil. Each spectral transformation corresponded to a specific sensitive spectral interval. The accuracy of the inversion model of soil La content based on the method of variable importance evaluation was higher than that based on the correlation coefficient of variables. Among them, the best model was the first-order reciprocal of absorbance. The value of prediction R2 reached 0.89, but the RMSE was 36.26 mg/kg, and the mean relative error reached 45.97%, showing a poor effect. The inversion model of characteristic variables extracted by the method of variable importance evaluation and screening showed that CARS-GA-ELM had the best effect, with R2, RMSE and MRE reaching 0.99, 11.36 mg/kg, 11.87%, respectively, which could be well used to detect the content of La element. The research provided a new testing method theory for the fast and quantitative inversion of La element in soil on spot, showed a thought for the hyperspectral detection of other rare earth elements, and also provided a theoretical basis for the quantitative inversion and evaluation of regional hyperspectral rare earth resources.
This work studied on La element, which hosted in the Sedimentary rare earth deposits of the Permian Xuanwei Formation, Northwest Guizhou Province. Based on the study of rare earth soil spectroscopy, the hyperspectral quantitative estimation and inversion of La element were carried out under GA-ELM model. After a variety of spectral transformations (S-G smoothing, differential, reciprocal, continuum removal), the accuracy differences of the mathematical models established by two methods of selecting characteristic variables (Pearson correlation coefficient and variable importance assessment (CARS, SPA, RF)) were studied and compared. The results showed that there was a non-linear relationship between the content of La in mineral samples and the spectral reflectance. Different spectral transformation methods had different ability to extract the information of La content in soil. Each spectral transformation corresponded to a specific sensitive spectral interval. The accuracy of the inversion model of soil La content based on the method of variable importance evaluation was higher than that based on the correlation coefficient of variables. Among them, the best model was the first-order reciprocal of absorbance. The value of prediction R2 reached 0.89, but the RMSE was 36.26 mg/kg, and the mean relative error reached 45.97%, showing a poor effect. The inversion model of characteristic variables extracted by the method of variable importance evaluation and screening showed that CARS-GA-ELM had the best effect, with R2, RMSE and MRE reaching 0.99, 11.36 mg/kg, 11.87%, respectively, which could be well used to detect the content of La element. The research provided a new testing method theory for the fast and quantitative inversion of La element in soil on spot, showed a thought for the hyperspectral detection of other rare earth elements, and also provided a theoretical basis for the quantitative inversion and evaluation of regional hyperspectral rare earth resources.
2021, 49(2): 301-308
doi: 10.19756/j.issn.0253-3820.201292
Abstract:
Boletus griseus (B.griseus) is one of wild edible Boletaceae mushrooms in Yunnan province. B.griseus shows a strong bioaccumulation for Cd. This work aimed to elucidate the factors affecting the Cd migration from soil matrix to mushroom, to explore the bioconcentration mechanisms of B.griseus for Cd. A total of 22 samples of fresh B.griseus and colonied soil were collected, and the total Cd contents and the Cd occurrence in fruiting bodies and soil matrix were determined. And the physical and chemical properties of soil matrix were analyzed. The results showed that the total Cd contents of 22 mushrooms samples were 8.69- 24.19 mg/kg DW, and the water soluble Cd made up the highest proportion, exhibiting potential food safety risks. Total Cd contents in soil matrix were 0.03-0.57 mg/kg DW and the Fe-Mn oxides and exchangeable speciation were key constituents for Cd. Bioconcentration factors of B.griseus for Cd were 24.14-386.00. Principal component analysis elucidated that Cd content in soil, electrical conductivity (EC), total carbon (TC), total nitrogen (TN), pH and dissolved organic carbon (DOC) were the factors affecting the Cd accumulation by B.griseus. Multiple regression analysis calculated the infection of the factors quantitatively, being Cdmushroom=3.945Cdsoil+0.214EC+1.658TC+0.326TN-5.432pH-0.526Clay-0.364TDS+42.196 (R=0.793, P=0.025).
Boletus griseus (B.griseus) is one of wild edible Boletaceae mushrooms in Yunnan province. B.griseus shows a strong bioaccumulation for Cd. This work aimed to elucidate the factors affecting the Cd migration from soil matrix to mushroom, to explore the bioconcentration mechanisms of B.griseus for Cd. A total of 22 samples of fresh B.griseus and colonied soil were collected, and the total Cd contents and the Cd occurrence in fruiting bodies and soil matrix were determined. And the physical and chemical properties of soil matrix were analyzed. The results showed that the total Cd contents of 22 mushrooms samples were 8.69- 24.19 mg/kg DW, and the water soluble Cd made up the highest proportion, exhibiting potential food safety risks. Total Cd contents in soil matrix were 0.03-0.57 mg/kg DW and the Fe-Mn oxides and exchangeable speciation were key constituents for Cd. Bioconcentration factors of B.griseus for Cd were 24.14-386.00. Principal component analysis elucidated that Cd content in soil, electrical conductivity (EC), total carbon (TC), total nitrogen (TN), pH and dissolved organic carbon (DOC) were the factors affecting the Cd accumulation by B.griseus. Multiple regression analysis calculated the infection of the factors quantitatively, being Cdmushroom=3.945Cdsoil+0.214EC+1.658TC+0.326TN-5.432pH-0.526Clay-0.364TDS+42.196 (R=0.793, P=0.025).
2021, 49(2): 309-317
doi: 10.19756/j.issn.0253-3820.201231
Abstract:
The composite of gold nanoparticles-graphene oxide(AuNPs-GO) was prepared and characterized by transmission electron microscope (TEM) and ultraviolet-visible(UV-vis) spectrophotometry, respectively. The composite was modified on the surface of a glassy carbon electrode (GCE). The mercapto-modified and guanine-rich DNA strand (T30695) was self-assembled on to gold nanoparticles on the surface of the electrode via Au-S bond. T30695 could combine with lead ions (Pb2+) to form a stable parallel G-quadruplex. The G-quadruplex further combined with hemin to form DNAzyme with peroxidase activity. On the basis of this, a DNAzyme electrochemical sensor for Pb2+ detection was prepared. The DNAzyme could catalyze the oxidation reaction of hydrogen peroxidetowardshydroquinone (HQ) to achieve the amplification of electrochemical signal and highly sensitive detection of Pb2+. Under the optimum conditions, the peak current of square-wave voltammetry (SWV) was linearly dependent on the logarithm of Pb2+ concentration ranging from 5.0×10-9 mol/L to 1.0×10-6 mol/L with a detection limit of 1.0×10-9 mol/L(S/N=3). The recovery of Pb2+ in real water sample was 96%-105%. The sensor possessed good reproducibility, stability and selectivity to Pb2+.
The composite of gold nanoparticles-graphene oxide(AuNPs-GO) was prepared and characterized by transmission electron microscope (TEM) and ultraviolet-visible(UV-vis) spectrophotometry, respectively. The composite was modified on the surface of a glassy carbon electrode (GCE). The mercapto-modified and guanine-rich DNA strand (T30695) was self-assembled on to gold nanoparticles on the surface of the electrode via Au-S bond. T30695 could combine with lead ions (Pb2+) to form a stable parallel G-quadruplex. The G-quadruplex further combined with hemin to form DNAzyme with peroxidase activity. On the basis of this, a DNAzyme electrochemical sensor for Pb2+ detection was prepared. The DNAzyme could catalyze the oxidation reaction of hydrogen peroxidetowardshydroquinone (HQ) to achieve the amplification of electrochemical signal and highly sensitive detection of Pb2+. Under the optimum conditions, the peak current of square-wave voltammetry (SWV) was linearly dependent on the logarithm of Pb2+ concentration ranging from 5.0×10-9 mol/L to 1.0×10-6 mol/L with a detection limit of 1.0×10-9 mol/L(S/N=3). The recovery of Pb2+ in real water sample was 96%-105%. The sensor possessed good reproducibility, stability and selectivity to Pb2+.
