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2022 Volume 50 Issue 8
2022, 50(8): 1123-1130
doi: 10.19756/j.issn.0253-3820.221098
Abstract:
As a biocompatible and inexpensive metal, bismuth has been used to design and synthesize various nanoparticles with unique structures, compositions and physicochemical properties. The high X-ray attenuation coefficient and near-infrared absorption, excellent photothermal conversion efficiency, and long circulation half-life of bismuth-based nanoparticles make them promising for applications in cancer drug delivery, photothermal therapy and radiotherapy, multimodal imaging, theranostics, biosensing and tissue engineering. In this review, the applications of bismuth-based nanoparticles in biosensing and bioimaging were summarized, and the opportunities and challenges faced by bismuth-based nanoparticles were also discussed.
As a biocompatible and inexpensive metal, bismuth has been used to design and synthesize various nanoparticles with unique structures, compositions and physicochemical properties. The high X-ray attenuation coefficient and near-infrared absorption, excellent photothermal conversion efficiency, and long circulation half-life of bismuth-based nanoparticles make them promising for applications in cancer drug delivery, photothermal therapy and radiotherapy, multimodal imaging, theranostics, biosensing and tissue engineering. In this review, the applications of bismuth-based nanoparticles in biosensing and bioimaging were summarized, and the opportunities and challenges faced by bismuth-based nanoparticles were also discussed.
2022, 50(8): 1131-1142
doi: 10.19756/j.issn.0253-3820.221027
Abstract:
Soil pollutants possess the characteristics of diversity, difficult degradation and easy accumulation. They can affect people's health through crop absorption and food chain pathways. Fluorescent probes have the properties of wide range of synthetic materials and easy modification, and have been widely used in the highly sensitive and selective detection of soil pollutants. This article discusses the concept, detection mechanism and classification of fluorescent probes, summarizes the research progress of different types of fluorescent probes in detection of inorganic pollutants, organic pollutants and microbial pollutants in soil in recent years, and discusses their development prospects.
Soil pollutants possess the characteristics of diversity, difficult degradation and easy accumulation. They can affect people's health through crop absorption and food chain pathways. Fluorescent probes have the properties of wide range of synthetic materials and easy modification, and have been widely used in the highly sensitive and selective detection of soil pollutants. This article discusses the concept, detection mechanism and classification of fluorescent probes, summarizes the research progress of different types of fluorescent probes in detection of inorganic pollutants, organic pollutants and microbial pollutants in soil in recent years, and discusses their development prospects.
2022, 50(8): 1143-1149
doi: 10.19756/j.issn.0253-3820.221094
Abstract:
A self-aspiration corona discharge ionization source was constructed for detection of volatile organic compounds (VOCs). This source had a simple structure that used the tip of a syringe needle to generate the corona discharge. In addition, the hollow needle could also be used as the introduction pathway for the gaseous sample, which allowed the gas to pass through the corona zone efficiently to improve the ionization efficiency. The needle tip was placed in a sealed chamber that was directly connected to the sampling interface of the mass spectrometer. This design could not only utilize the pumping capability of the instrument for self-aspiration sampling, but also avoid the influence of ambient factors on the ionization process. Moreover, the developed hollow needle corona discharge (HNCD) source could be used with a syringe cylinder to facilitate the collection, storage and automatic injection of gas samples. The experimental test results showed that the HNCD source had various merits, including easy operation, fast response and good stability. The detection limit of aniline acquired using this device was at nL/L level, which showed a good application prospect.
A self-aspiration corona discharge ionization source was constructed for detection of volatile organic compounds (VOCs). This source had a simple structure that used the tip of a syringe needle to generate the corona discharge. In addition, the hollow needle could also be used as the introduction pathway for the gaseous sample, which allowed the gas to pass through the corona zone efficiently to improve the ionization efficiency. The needle tip was placed in a sealed chamber that was directly connected to the sampling interface of the mass spectrometer. This design could not only utilize the pumping capability of the instrument for self-aspiration sampling, but also avoid the influence of ambient factors on the ionization process. Moreover, the developed hollow needle corona discharge (HNCD) source could be used with a syringe cylinder to facilitate the collection, storage and automatic injection of gas samples. The experimental test results showed that the HNCD source had various merits, including easy operation, fast response and good stability. The detection limit of aniline acquired using this device was at nL/L level, which showed a good application prospect.
2022, 50(8): 1150-1157
doi: 10.19756/j.issn.0253-3820.221164
Abstract:
An experimental system on the basis of inductively coupled plasma optical emission spectrometer (ICP-OES) was built based on digital micromirror device (DMD), which was consisted of light source system, sample introduction system, echelle grating spectrometer and control system. The echelle grating spectrometer used echelle grating and reflective prism as the cross-dispersion elements, DMD as the spatial light modulator, and photomultiplier tubes (PMT) as the detector. The working parameters of the experimental system including control parameters of DMD, power of high frequency generator and flow rate of carrier gas were optimized. According to the experimental results of the emission lines, the limit of detection (LOD) was less than 0.05 μg/mL for Mg and 0.01 μg/mL for Ca, respectively. By analyzing the corresponding standard solution sample, the spiked recoveries and the RSDs were 98%-103% and 0.9%-1.8% for Mg, and 89%-93% and 0.8%-0.9% for Ca, respectively. The experimental results showed that the ICP-OES based on DMD had the characteristics of flexible measurement and fast detection, realizing the function of detection and analysis.
An experimental system on the basis of inductively coupled plasma optical emission spectrometer (ICP-OES) was built based on digital micromirror device (DMD), which was consisted of light source system, sample introduction system, echelle grating spectrometer and control system. The echelle grating spectrometer used echelle grating and reflective prism as the cross-dispersion elements, DMD as the spatial light modulator, and photomultiplier tubes (PMT) as the detector. The working parameters of the experimental system including control parameters of DMD, power of high frequency generator and flow rate of carrier gas were optimized. According to the experimental results of the emission lines, the limit of detection (LOD) was less than 0.05 μg/mL for Mg and 0.01 μg/mL for Ca, respectively. By analyzing the corresponding standard solution sample, the spiked recoveries and the RSDs were 98%-103% and 0.9%-1.8% for Mg, and 89%-93% and 0.8%-0.9% for Ca, respectively. The experimental results showed that the ICP-OES based on DMD had the characteristics of flexible measurement and fast detection, realizing the function of detection and analysis.
2022, 50(8): 1158-1167,1187
doi: 10.19756/j.issn.0253-3820.221085
Abstract:
Digital nucleic acid analysis is a favorable tool for rapid molecular detection of pathogens due to its absolute quantification capability without the necessity of standard curves. However, current digital nucleic acid analysis platforms commonly perform the workflow with discrete facilities, which complicates the operation process and lengthens the turnaround time, therefore restricting its adoption in resource-limited settings. To address this issue, an integrated microfluidic droplet digital isothermal amplification system was developed in this work. This system integrated sequential droplets-based nucleic acid extraction unit, syringe-vacuum actuated droplet generation unit, and droplet digital loop-mediated isothermal amplification (LAMP) unit, achieving digital analysis of bacterial nucleic acid within 1.5 h in an integrated manner. The nucleic acid extraction unit could complete E.coli genomic DNA extraction with the efficiency of 93.68%±32.38%, the droplet generation unit could produce 20000 droplets in 4 min with the relative standard deviation (RSD) less than 10%. The LAMP reaction could be performed with a linear dynamic range of 4 orders of magnitude (2.36×104-1.71×1 07 CFU/mL). Compared to traditional culture method, the results obtained from analysis of E.coli in UTI clinical samples (n=13) showed that both the detection sensitivity and specificity of this digital nucleic acid analysis method were 100% (Kappa=1, p<0.01). With the advantages of accurate quantification and ease of operation, this integrated microfluidic droplet digital isothermal amplification system was expected to be a favorable tool for rapid point-of-care detection of pathogens in resource-limited settings.
Digital nucleic acid analysis is a favorable tool for rapid molecular detection of pathogens due to its absolute quantification capability without the necessity of standard curves. However, current digital nucleic acid analysis platforms commonly perform the workflow with discrete facilities, which complicates the operation process and lengthens the turnaround time, therefore restricting its adoption in resource-limited settings. To address this issue, an integrated microfluidic droplet digital isothermal amplification system was developed in this work. This system integrated sequential droplets-based nucleic acid extraction unit, syringe-vacuum actuated droplet generation unit, and droplet digital loop-mediated isothermal amplification (LAMP) unit, achieving digital analysis of bacterial nucleic acid within 1.5 h in an integrated manner. The nucleic acid extraction unit could complete E.coli genomic DNA extraction with the efficiency of 93.68%±32.38%, the droplet generation unit could produce 20000 droplets in 4 min with the relative standard deviation (RSD) less than 10%. The LAMP reaction could be performed with a linear dynamic range of 4 orders of magnitude (2.36×104-1.71×1 07 CFU/mL). Compared to traditional culture method, the results obtained from analysis of E.coli in UTI clinical samples (n=13) showed that both the detection sensitivity and specificity of this digital nucleic acid analysis method were 100% (Kappa=1, p<0.01). With the advantages of accurate quantification and ease of operation, this integrated microfluidic droplet digital isothermal amplification system was expected to be a favorable tool for rapid point-of-care detection of pathogens in resource-limited settings.
2022, 50(8): 1168-1178
doi: 10.19756/j.issn.0253-3820.210775
Abstract:
On the basis of polyethylene glycol (PEG) precipitation enrichment and improved pre-amplified reverse transcription-quantitative polymerase chain reaction (RT-qPCR), a method was established for highly sensitive detection of low-dose contamination of hepatitis A virus (HAV) in small berries. The treatment time of HAV in strawberry enriched by PEG precipitation was optimized, and the pre-amplification steps were set up to accelerate the lysis of sample nucleic acid and enrichment of templates. By using this method, the recovery was 15.51%, the lowest detection sensitivity could be up to 4.49 CCID50/mL of HAV attenuated vaccine titer, and the sensitivity of HAV plasmid was as low as 3.5 copies/μL. Compared with ISO/TS15216-2:2019 standard method, this method had higher detection efficiency and was suitable for detection of trace contaminated HAV in small berries. The positive rate of HAV in 78 batches of commercially available small berry samples was 5.13%, which was higher than that of ISO/TS 15216-2:2019 standard (1.28%). This method showed good applicability and application prospect for detection of low-dose HAV virus contamination in small berries.
On the basis of polyethylene glycol (PEG) precipitation enrichment and improved pre-amplified reverse transcription-quantitative polymerase chain reaction (RT-qPCR), a method was established for highly sensitive detection of low-dose contamination of hepatitis A virus (HAV) in small berries. The treatment time of HAV in strawberry enriched by PEG precipitation was optimized, and the pre-amplification steps were set up to accelerate the lysis of sample nucleic acid and enrichment of templates. By using this method, the recovery was 15.51%, the lowest detection sensitivity could be up to 4.49 CCID50/mL of HAV attenuated vaccine titer, and the sensitivity of HAV plasmid was as low as 3.5 copies/μL. Compared with ISO/TS15216-2:2019 standard method, this method had higher detection efficiency and was suitable for detection of trace contaminated HAV in small berries. The positive rate of HAV in 78 batches of commercially available small berry samples was 5.13%, which was higher than that of ISO/TS 15216-2:2019 standard (1.28%). This method showed good applicability and application prospect for detection of low-dose HAV virus contamination in small berries.
2022, 50(8): 1179-1187,1242
doi: 10.19756/j.issn.0253-3820.221117
Abstract:
Sequence coverage of identified proteins could be significantly improved when human urine proteins were effectively separated based on multi-dimensional liquid chromatography (MDLC). The high-efficient two-dimensional (2D) separating system involved strong anion exchange chromatography as the first dimension (1stD-SAX) and reversed phase liquid chromatography as the second dimension (2ndD-RPLC). After optimization of separate conditions, the peak capacity of 2D chromatographic system exceeded 40000. With regard to technique demands and ability to identify, 50 fractions were collected in the first dimension and 64 fractions were collected in the second dimension respectively, with valid peak capacity reaching 3200. On the basis of this system, the separation of intact proteins as well as the deep coverage of identification could be realized in human urine proteome. Urine samples from a group of healthy volunteers were collected and pretreatment including centrifugation and ultrafiltration was conducted subsequently to purify samples. To further improve pertinence, all samples were initially separated by 1stD-SAX, and the fraction 14 collected from 39 to 42 min was regarded as the main target. Fraction 14 was divided equally into two parts. One was digested and identified directly to obtain mass spectrometry (MS) data, while the other was further separated by 2ndD-RPLC and 64 fractions were collected. Then the 64 fractions were digested and identified individually to obtain aggregate data. Statistics indicated that 628 proteins were identified without 2ndD-RPLC separation while 2440 proteins were identified from 64 fractions. Among 588 proteins identified in common, the sequence coverage was significantly improved when a 2D separation was involved. Further analysis revealed that the sequence coverage of proteins composed of no more than 500 amino acids (AAs) reached 31.30%, a 2.02 fold-change compared with merely one-dimensional (1D) separation. For proteins composed of 501-1000 AAs, the sequence coverage increased from 7.79% in 1D separation to 21.35% in 2D separation. For larger proteins composed of over 1000 AAs, the sequence coverage could be enhanced by 3.87 times. These results verified the extraordinary improvement in coverage and reliability of identification when proteins were adequately separated by MDLC compared with the commonly used shotgun method. Meanwhile, the peptide counts from MS analysis could be increased to reduce the probability of mismatch or omission, thus contributing to acquiring more complete and detailed information on protein sequence, which was of great significance to realize deep coverage identification of proteome and establish more accurate proteomic databases.
Sequence coverage of identified proteins could be significantly improved when human urine proteins were effectively separated based on multi-dimensional liquid chromatography (MDLC). The high-efficient two-dimensional (2D) separating system involved strong anion exchange chromatography as the first dimension (1stD-SAX) and reversed phase liquid chromatography as the second dimension (2ndD-RPLC). After optimization of separate conditions, the peak capacity of 2D chromatographic system exceeded 40000. With regard to technique demands and ability to identify, 50 fractions were collected in the first dimension and 64 fractions were collected in the second dimension respectively, with valid peak capacity reaching 3200. On the basis of this system, the separation of intact proteins as well as the deep coverage of identification could be realized in human urine proteome. Urine samples from a group of healthy volunteers were collected and pretreatment including centrifugation and ultrafiltration was conducted subsequently to purify samples. To further improve pertinence, all samples were initially separated by 1stD-SAX, and the fraction 14 collected from 39 to 42 min was regarded as the main target. Fraction 14 was divided equally into two parts. One was digested and identified directly to obtain mass spectrometry (MS) data, while the other was further separated by 2ndD-RPLC and 64 fractions were collected. Then the 64 fractions were digested and identified individually to obtain aggregate data. Statistics indicated that 628 proteins were identified without 2ndD-RPLC separation while 2440 proteins were identified from 64 fractions. Among 588 proteins identified in common, the sequence coverage was significantly improved when a 2D separation was involved. Further analysis revealed that the sequence coverage of proteins composed of no more than 500 amino acids (AAs) reached 31.30%, a 2.02 fold-change compared with merely one-dimensional (1D) separation. For proteins composed of 501-1000 AAs, the sequence coverage increased from 7.79% in 1D separation to 21.35% in 2D separation. For larger proteins composed of over 1000 AAs, the sequence coverage could be enhanced by 3.87 times. These results verified the extraordinary improvement in coverage and reliability of identification when proteins were adequately separated by MDLC compared with the commonly used shotgun method. Meanwhile, the peptide counts from MS analysis could be increased to reduce the probability of mismatch or omission, thus contributing to acquiring more complete and detailed information on protein sequence, which was of great significance to realize deep coverage identification of proteome and establish more accurate proteomic databases.
2022, 50(8): 1188-1195
doi: 10.19756/j.issn.0253-3820.221116
Abstract:
The electrical properties of stem cells during development were investigated based on bioimpedance spectroscopy. First, a high-precision bioimpedance spectroscopy sensor for monitoring stem cell development process was developed. The sensor adopted an inverted tapered structure to realize the self-adaptation of the detection target size, and the electric field was concentrated and narrowed by the tapered chamber. The electric field in the detection area was homogenized to improve the detection accuracy of stem cells. Then, the structure of the sensor was verified and optimized by numerical simulation method. The results showed that the sensor could avoid the influence of positional changes during the development of stem cells on the detection results, and was more sensitive to the size changes of developing stem cells. The structural parameters were optimized, and the optimal monitoring sensitivity was 0.882. Finally, the proposed method was verified by experiment. Taking zebrafish embryonic stem cells as the monitoring object, the development process was monitored for 30 hours. The experimental results showed that with the development of zebrafish embryos, the impedance value gradually increased, and the relaxation frequency decreased gradually (from 1870 kHz to 481 kHz). The results showed that the sensor and monitoring method designed in this work could achieve high-precision monitoring of the developmental process of stem cells.
The electrical properties of stem cells during development were investigated based on bioimpedance spectroscopy. First, a high-precision bioimpedance spectroscopy sensor for monitoring stem cell development process was developed. The sensor adopted an inverted tapered structure to realize the self-adaptation of the detection target size, and the electric field was concentrated and narrowed by the tapered chamber. The electric field in the detection area was homogenized to improve the detection accuracy of stem cells. Then, the structure of the sensor was verified and optimized by numerical simulation method. The results showed that the sensor could avoid the influence of positional changes during the development of stem cells on the detection results, and was more sensitive to the size changes of developing stem cells. The structural parameters were optimized, and the optimal monitoring sensitivity was 0.882. Finally, the proposed method was verified by experiment. Taking zebrafish embryonic stem cells as the monitoring object, the development process was monitored for 30 hours. The experimental results showed that with the development of zebrafish embryos, the impedance value gradually increased, and the relaxation frequency decreased gradually (from 1870 kHz to 481 kHz). The results showed that the sensor and monitoring method designed in this work could achieve high-precision monitoring of the developmental process of stem cells.
2022, 50(8): 1196-1204
doi: 10.19756/j.issn.0253-3820.221016
Abstract:
Surface enhanced Raman scattering (SERS) is a molecular specific hypersensitive spectroscopy technique. However, the existing SERS are mainly limited to extracorporeal sensing. Silver (Ag) material has become the mostly used SERS substrate because of its excellent surface plasmon resonance (SPR) characteristics. However, poor chemical stability and biocompatibility limit its biomedical applications. Therefore, optimizing the SPR activity and stability of Ag materials has become the research focus to broaden its application in vivo. In this study, Au@Ag core-shell nanorods (Au@Ag NRs) were synthesized by chemical deposition. The detection results of transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), energy dispersive X-ray element mapping (EDX) and X-ray diffraction (XRD) proved that Au@Ag NRs were successfully synthesized. Then, the near infrared Raman molecules of diethylthioacridine carbonyl iodine (DTTC) and mercaptopolyethylene glycol (PEG-SH) were coupled to Au@Ag NRs (pDAu@Ag NRs) to evaluate SERS properties both in vitro and in vivo. Ultraviolet visible spectrophotometer (UV-Vis) characterization revealed that pDAu@Ag NRs had good SPR characteristics in the near infrared region, resulting in good SERS properties in vitro. Inductively coupled plasma optical emission spectroscopy (ICP-OES) showed little dissociation of Ag ions, which was not enough to cause biological toxicity. MTS (3-(4,5-dimethylthiazole-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H tetrazole) test further confirmed that pDAu@Ag NRs had good biocompatibility, ensuring the safe application in vivo. Finally, pDAu@Ag NRs was used for Raman imaging of human breast cancer (MCF-7) cells and Raman biosensing in MCF-7 tumor-bearing mice. The results showed that Au@Ag NRs had excellent SERS imaging ability in MCF-7 cells and maintained high SERS activity on the tumor site. This technique may be helpful for early monitoring and spectroscopic diagnosis of breast cancer.
Surface enhanced Raman scattering (SERS) is a molecular specific hypersensitive spectroscopy technique. However, the existing SERS are mainly limited to extracorporeal sensing. Silver (Ag) material has become the mostly used SERS substrate because of its excellent surface plasmon resonance (SPR) characteristics. However, poor chemical stability and biocompatibility limit its biomedical applications. Therefore, optimizing the SPR activity and stability of Ag materials has become the research focus to broaden its application in vivo. In this study, Au@Ag core-shell nanorods (Au@Ag NRs) were synthesized by chemical deposition. The detection results of transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), energy dispersive X-ray element mapping (EDX) and X-ray diffraction (XRD) proved that Au@Ag NRs were successfully synthesized. Then, the near infrared Raman molecules of diethylthioacridine carbonyl iodine (DTTC) and mercaptopolyethylene glycol (PEG-SH) were coupled to Au@Ag NRs (pDAu@Ag NRs) to evaluate SERS properties both in vitro and in vivo. Ultraviolet visible spectrophotometer (UV-Vis) characterization revealed that pDAu@Ag NRs had good SPR characteristics in the near infrared region, resulting in good SERS properties in vitro. Inductively coupled plasma optical emission spectroscopy (ICP-OES) showed little dissociation of Ag ions, which was not enough to cause biological toxicity. MTS (3-(4,5-dimethylthiazole-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H tetrazole) test further confirmed that pDAu@Ag NRs had good biocompatibility, ensuring the safe application in vivo. Finally, pDAu@Ag NRs was used for Raman imaging of human breast cancer (MCF-7) cells and Raman biosensing in MCF-7 tumor-bearing mice. The results showed that Au@Ag NRs had excellent SERS imaging ability in MCF-7 cells and maintained high SERS activity on the tumor site. This technique may be helpful for early monitoring and spectroscopic diagnosis of breast cancer.
2022, 50(8): 1205-1216
doi: 10.19756/j.issn.0253-3820.221122
Abstract:
The polydopamine/poly(acrylic acid)-copper hydroxide Janus nanoparticles (PDA/PAA-Cu(OH)2 JNPs) were prepared by a novel and simple method. PDA had a strong absorption in the near infrared (NIR) region, with excellent biocompatibility and degradation, and the PAA-Cu(OH)2 was formed via coordination between the carboxyl groups of PAA and copper ions (Cu2+) by introducing Cu(NO3)2, which was used for loading anticancer drug. The PAA-Cu(OH)2 domains also had strong absorption in the NIR region for photothermal therapy, realizing the organic fusion of different functions and showing synergistic effect. The hydrophilic doxorubicin (DOX) was chosen as drug model for exposing the inhibition efficiency of the HepG-2 cells. The obtained JNPs had high drug-loading contents (0.87 mg/mg, DOX/JNPs), good photothermal conversion efficiency (45.9%), pH/NIR bimodal-triggered controlled drug release ability and photoacoustic (PA) imaging capacity, enabling the JNPs to be applied to PA imaging and synergistic cancer chemo-phototherapy in vitro. The cytotoxicity assay in vitro proved that the group treated with DOX-loaded PDA/PAA-Cu(OH)2 JNPs plus laser showed distinct cell death, and the viability of the cells were exceedingly low (7.9%).
The polydopamine/poly(acrylic acid)-copper hydroxide Janus nanoparticles (PDA/PAA-Cu(OH)2 JNPs) were prepared by a novel and simple method. PDA had a strong absorption in the near infrared (NIR) region, with excellent biocompatibility and degradation, and the PAA-Cu(OH)2 was formed via coordination between the carboxyl groups of PAA and copper ions (Cu2+) by introducing Cu(NO3)2, which was used for loading anticancer drug. The PAA-Cu(OH)2 domains also had strong absorption in the NIR region for photothermal therapy, realizing the organic fusion of different functions and showing synergistic effect. The hydrophilic doxorubicin (DOX) was chosen as drug model for exposing the inhibition efficiency of the HepG-2 cells. The obtained JNPs had high drug-loading contents (0.87 mg/mg, DOX/JNPs), good photothermal conversion efficiency (45.9%), pH/NIR bimodal-triggered controlled drug release ability and photoacoustic (PA) imaging capacity, enabling the JNPs to be applied to PA imaging and synergistic cancer chemo-phototherapy in vitro. The cytotoxicity assay in vitro proved that the group treated with DOX-loaded PDA/PAA-Cu(OH)2 JNPs plus laser showed distinct cell death, and the viability of the cells were exceedingly low (7.9%).
2022, 50(8): 1217-1223
doi: 10.19756/j.issn.0253-3820.221066
Abstract:
A simple, rapid and environmentally friendly method named column-free matrix solid-phase dispersion (FMSPD) was developed for extraction of camptothecin from the fruits of Camptotheca acuminate Decne. Cucurbit[7]uril (Q[7]) was used as the sorbent of FMSPD to selectively extract camptothecin, which was transferred into an aqueous solution and was directly detected using high performance liquid chromatography-ultraviolet detector (HPLC-UV) based on the recognition interaction of Q[7] toward the compound. The factors that influenced the extraction efficiency were investigated, including the amount of Q[7], grinding time, volume of added water, and pH value of the solution. Under the optimal experimental conditions, the dynamic linear range of the developed FMSPD-HPLC-UC method was 1.0-100 μg/mL, the limit of detection was 0.15 μg/mL, and the intra- and inter-day precisions were 4.5% and 5.2%, respectively. The mean recoveries (n=3) at three spiked concentration levels were from 97.1% to 119.3%. The developed method was applied to analyze four kinds of fruits of Camptotheca acuminate Decne.F- and t-tests showed that the results had no significant difference when comparing the traditional ultrasound-assisted extraction method to the novel FMSPD extraction method. However the method developed here was simpler, faster and did not use organic solvents.
A simple, rapid and environmentally friendly method named column-free matrix solid-phase dispersion (FMSPD) was developed for extraction of camptothecin from the fruits of Camptotheca acuminate Decne. Cucurbit[7]uril (Q[7]) was used as the sorbent of FMSPD to selectively extract camptothecin, which was transferred into an aqueous solution and was directly detected using high performance liquid chromatography-ultraviolet detector (HPLC-UV) based on the recognition interaction of Q[7] toward the compound. The factors that influenced the extraction efficiency were investigated, including the amount of Q[7], grinding time, volume of added water, and pH value of the solution. Under the optimal experimental conditions, the dynamic linear range of the developed FMSPD-HPLC-UC method was 1.0-100 μg/mL, the limit of detection was 0.15 μg/mL, and the intra- and inter-day precisions were 4.5% and 5.2%, respectively. The mean recoveries (n=3) at three spiked concentration levels were from 97.1% to 119.3%. The developed method was applied to analyze four kinds of fruits of Camptotheca acuminate Decne.F- and t-tests showed that the results had no significant difference when comparing the traditional ultrasound-assisted extraction method to the novel FMSPD extraction method. However the method developed here was simpler, faster and did not use organic solvents.
2022, 50(8): 1224-1232,1251
doi: 10.19756/j.issn.0253-3820.221026
Abstract:
One-dimensional doubly selective total correlation spectroscopy (1D TOCSY-TOCSY) nuclear magnetic resonance (NMR) method was constructed using 1D TOCSY as editing module. 1D TOCSY-TOCSY was applied to screen and identify thiodiglycol (TDG) in the complex mixtures, where TDG was a chemical subject to supervision and control and was used as the model compound.In the sample condition that the 1H signal of TDG was completely covered by 300-2000 times of background, only TDG was visible without any background in 1D TOCSY-TOCSY spectra. The limit of detection for TDG was 5 μg/mL when 256 scans were completed within 20 min. The limit of detection for TDG could reach 100 ng/mL when 8000 scans were acquired in 12 h. Compared with the traditional 1D TOCSY, 1D NOESY selective excitation and chemical shift selective filtering (CSSF) techniques, 1D TOCSY-TOCSY method showed outstanding selective detection capability. It was 20 times more sensitive than the existing 1D STEP-NOESY doubly selective excitation technique. This study provided a new analytical method for screening and identification of the trace chemicals subject to supervision and control in complex matrix samples and could be applied to other mixture analysis.
One-dimensional doubly selective total correlation spectroscopy (1D TOCSY-TOCSY) nuclear magnetic resonance (NMR) method was constructed using 1D TOCSY as editing module. 1D TOCSY-TOCSY was applied to screen and identify thiodiglycol (TDG) in the complex mixtures, where TDG was a chemical subject to supervision and control and was used as the model compound.In the sample condition that the 1H signal of TDG was completely covered by 300-2000 times of background, only TDG was visible without any background in 1D TOCSY-TOCSY spectra. The limit of detection for TDG was 5 μg/mL when 256 scans were completed within 20 min. The limit of detection for TDG could reach 100 ng/mL when 8000 scans were acquired in 12 h. Compared with the traditional 1D TOCSY, 1D NOESY selective excitation and chemical shift selective filtering (CSSF) techniques, 1D TOCSY-TOCSY method showed outstanding selective detection capability. It was 20 times more sensitive than the existing 1D STEP-NOESY doubly selective excitation technique. This study provided a new analytical method for screening and identification of the trace chemicals subject to supervision and control in complex matrix samples and could be applied to other mixture analysis.
2022, 50(8): 1233-1242
doi: 10.19756/j.issn.0253-3820.210771
Abstract:
Heavy metals have the characteristics of low concentration, high toxicity and biological undegradability. The heavy metal ion pollution of environmental water systems pose a great threat to human health. In this work, carboxy carbon nanotubes (MWCNT-COOH) and dialyzed graphene oxide (GO) were bonded to form a 3D mixed-aerogels (MAs) of hierarchical porous structure with polydopamine (PDA) as the "cross-linking agent", similar to "cabbage-like". Bismuth nanoparticles (BiNPs) were loaded in situ on MAs as the substrate to construct an electrochemical sensor. Differential pulse stripping voltammetry (DPSV) was used to detect Pb2+ and Cd2+ simultaneously. The linear ranges were 5-500 ng/L and 0.5-70 μg/L, and the corresponding detection limits (S/N=3) were 0.13 ng/L and 0.49 ng/L for Pb2+ and Cd2+, respectively. The experimental results showed that the sensor had high accuracy, high stability and anti-interference properties. The sensor was expected to be of great significance for simultaneous detection of heavy metals.
Heavy metals have the characteristics of low concentration, high toxicity and biological undegradability. The heavy metal ion pollution of environmental water systems pose a great threat to human health. In this work, carboxy carbon nanotubes (MWCNT-COOH) and dialyzed graphene oxide (GO) were bonded to form a 3D mixed-aerogels (MAs) of hierarchical porous structure with polydopamine (PDA) as the "cross-linking agent", similar to "cabbage-like". Bismuth nanoparticles (BiNPs) were loaded in situ on MAs as the substrate to construct an electrochemical sensor. Differential pulse stripping voltammetry (DPSV) was used to detect Pb2+ and Cd2+ simultaneously. The linear ranges were 5-500 ng/L and 0.5-70 μg/L, and the corresponding detection limits (S/N=3) were 0.13 ng/L and 0.49 ng/L for Pb2+ and Cd2+, respectively. The experimental results showed that the sensor had high accuracy, high stability and anti-interference properties. The sensor was expected to be of great significance for simultaneous detection of heavy metals.
2022, 50(8): 1243-1251
doi: 10.19756/j.issn.0253-3820.210621
Abstract:
A method including sample pretreatment and instrumental detection was developed for quantifying 57 kinds of per- and polyfluoroalkyl substances (PFAS) in surface water, influent and effluent water of wastewater treatment plants (WWTPs), sediment and biological samples. The water samples and sediment samples were concentrated and purified by WAX solid phase extraction (SPE) columns and ion-pairing liquid-extraction method, respectively; while the fish samples were firstly digested with alkaline to protein and fat, and then extracted by WAX SPE column. The target PFAS were detected by ultra-high liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) in negative electrospray ionization (ESI-) mode and quantified with internal standard method and calibration curve (0.5-100 μg/L). All PFAS could be separated within 10 min and the determination coefficients for PFAS were all >0.99. The recoveries of 57 kinds of PFAS in surface water, influent and effluent waters, sediment and fish were 61.2%-143.0%, 60.1%-128.0%, 60.5%-128.0%, 60.3%-134.0% and 60.9%-127.0%, respectively, with relative standard deviations (RSDs) ranging from 0.18% to 24%. Besides, the method quantification limits (MQLs) were 0.04-6.90 ng/L, 0.05-8.50 ng/L, 0.04-9.30 ng/L, 0.01-2.20 ng/g and 0.21-7.90 ng/g, respectively. The method was applied to determination of PFAS in water samples from Maozhou River, influent and effluent waters from a WWTP and fish samples from the North River. Twenty kinds of PFAS were found in the water and sediment from the Maozhou river, dominated by PFOS (50.5 ng/L and 8.79 ng/g, respectively); 11 kinds of PFAS were detected in the WWTP with PFOA as the main compound, and the removal rates were less than 25%. Only 8 kinds of longer chain-length PFAS were observed in the fish samples, dominated by PFOS (up to 14.8 ng/g). The established method was sensitive and accurate, and suitable for simultaneous detection of 57 kinds of PFAS in various environmental matrix and biological samples.
A method including sample pretreatment and instrumental detection was developed for quantifying 57 kinds of per- and polyfluoroalkyl substances (PFAS) in surface water, influent and effluent water of wastewater treatment plants (WWTPs), sediment and biological samples. The water samples and sediment samples were concentrated and purified by WAX solid phase extraction (SPE) columns and ion-pairing liquid-extraction method, respectively; while the fish samples were firstly digested with alkaline to protein and fat, and then extracted by WAX SPE column. The target PFAS were detected by ultra-high liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) in negative electrospray ionization (ESI-) mode and quantified with internal standard method and calibration curve (0.5-100 μg/L). All PFAS could be separated within 10 min and the determination coefficients for PFAS were all >0.99. The recoveries of 57 kinds of PFAS in surface water, influent and effluent waters, sediment and fish were 61.2%-143.0%, 60.1%-128.0%, 60.5%-128.0%, 60.3%-134.0% and 60.9%-127.0%, respectively, with relative standard deviations (RSDs) ranging from 0.18% to 24%. Besides, the method quantification limits (MQLs) were 0.04-6.90 ng/L, 0.05-8.50 ng/L, 0.04-9.30 ng/L, 0.01-2.20 ng/g and 0.21-7.90 ng/g, respectively. The method was applied to determination of PFAS in water samples from Maozhou River, influent and effluent waters from a WWTP and fish samples from the North River. Twenty kinds of PFAS were found in the water and sediment from the Maozhou river, dominated by PFOS (50.5 ng/L and 8.79 ng/g, respectively); 11 kinds of PFAS were detected in the WWTP with PFOA as the main compound, and the removal rates were less than 25%. Only 8 kinds of longer chain-length PFAS were observed in the fish samples, dominated by PFOS (up to 14.8 ng/g). The established method was sensitive and accurate, and suitable for simultaneous detection of 57 kinds of PFAS in various environmental matrix and biological samples.
2022, 50(8): 1252-1259
doi: 10.19756/j.issn.0253-3820.221145
Abstract:
Solution cathode glow discharge atomic emission spectrometry (SCGD-AES) has many advantages such as low power consumption, small size and simple operation. It is an ideal choice for on-line analysis of field samples. However, the low power consumption leads torelatively limited excitation capacity, which limits the detection performance of high excitation potential elements, such as chromium. In this study, a method for determination of chromium (Cr) content in sewage by solution cathode glow discharge atomic emission spectrometry operated in hydrogen-helium mixed atmosphere was established. It was found that the excitation conditions of SCGD-AES could be improved in hydrogen-helium mixed atmosphere (H2 content of 3%). The experimental parameters such as gas flow rate, electrolyte type and flow rate, discharge voltage and spacing were optimized. The results showed that the limit of detection (LOD) of Cr was improved from 650 μg/L (discharging in air) to 106 μg/L with great repeatability (RSD=1.3%, 10 mg/L, n=11). The determination results of Cr in brown rice flour reference material (GBW(E)100619) and actual industrial sewage by this method were consistent with those obtained by inductively coupled plasma-optical emission spectroscopy (ICP-OES)and the recoveries were 92.4%-104.0%, indicating that this method had superb application prospect in determination of Cr in water samples.
Solution cathode glow discharge atomic emission spectrometry (SCGD-AES) has many advantages such as low power consumption, small size and simple operation. It is an ideal choice for on-line analysis of field samples. However, the low power consumption leads torelatively limited excitation capacity, which limits the detection performance of high excitation potential elements, such as chromium. In this study, a method for determination of chromium (Cr) content in sewage by solution cathode glow discharge atomic emission spectrometry operated in hydrogen-helium mixed atmosphere was established. It was found that the excitation conditions of SCGD-AES could be improved in hydrogen-helium mixed atmosphere (H2 content of 3%). The experimental parameters such as gas flow rate, electrolyte type and flow rate, discharge voltage and spacing were optimized. The results showed that the limit of detection (LOD) of Cr was improved from 650 μg/L (discharging in air) to 106 μg/L with great repeatability (RSD=1.3%, 10 mg/L, n=11). The determination results of Cr in brown rice flour reference material (GBW(E)100619) and actual industrial sewage by this method were consistent with those obtained by inductively coupled plasma-optical emission spectroscopy (ICP-OES)and the recoveries were 92.4%-104.0%, indicating that this method had superb application prospect in determination of Cr in water samples.
2022, 50(8): 1260-1268
doi: 10.19756/j.issn.0253-3820.221225
Abstract:
The stability of organic acid metabolites and microbial communities structure contributed to improve the efficiency of anaerobic digestion in the large-scale biogas project. To study the relationship between the organic acid metabolites and microbial communities, three stirring speeds including 0, 80 and 200 r/min in a 4-L laboratory fermenter were set to monitor the physical and chemical qualitative changes such as volatile fatty acids during pig manure digestion. Combined with high-throughput sequencing technology, the evolution of microbial diversity and community structure in anaerobic digestion system was organically related to the metabolism of organic acids. The results indicated that, Firmicutes, Bacteroides, Proteobacteria and Euryarchaeota were the main dominant bacterial taxa in the microbial community structure. Firstly, moderate strring could improve the efficiency of anaerobic digestion and the stability of microbial community in the fermentation system in which the removal rate of total solids, volatile solids and chemical oxygen demand reached 79.15%, 63.63% and 87.89%, respectively. Moreover, as the main organic acid metabolites, the concentration of the acetic acid and propionic acid were positively correlated with Bacteroidetes and negatively correlated with Proteobacteria. Secondly, with high-speed stirring measure, the increased abundance of hydrogen-producing acetogens Synergistetes led to an increase in the abundance of Acidobacteria. Meanwhile, the concentration of acetic acid and propionic acid was increased by 21.09% and 6.44% respectively, and the abundance of hydrogenotrophic methanogens Methanocorpusculum was increased by 31.95%. Interestingly, the yield of methane had actually fallen. These data showed that excessive stirring during anaerobic digestion increased the concentrations of acetic acid and propionic acid significantly, and promoted the switchcover of methanogenic pathway from acetic acid pyrolysis pathway to less efficient acetic acid oxidation pathway. The results provided a new perspective for understanding the regulation between organic acid metabolism and methanogenic pathway in anaerobic digestion of pig manure.
The stability of organic acid metabolites and microbial communities structure contributed to improve the efficiency of anaerobic digestion in the large-scale biogas project. To study the relationship between the organic acid metabolites and microbial communities, three stirring speeds including 0, 80 and 200 r/min in a 4-L laboratory fermenter were set to monitor the physical and chemical qualitative changes such as volatile fatty acids during pig manure digestion. Combined with high-throughput sequencing technology, the evolution of microbial diversity and community structure in anaerobic digestion system was organically related to the metabolism of organic acids. The results indicated that, Firmicutes, Bacteroides, Proteobacteria and Euryarchaeota were the main dominant bacterial taxa in the microbial community structure. Firstly, moderate strring could improve the efficiency of anaerobic digestion and the stability of microbial community in the fermentation system in which the removal rate of total solids, volatile solids and chemical oxygen demand reached 79.15%, 63.63% and 87.89%, respectively. Moreover, as the main organic acid metabolites, the concentration of the acetic acid and propionic acid were positively correlated with Bacteroidetes and negatively correlated with Proteobacteria. Secondly, with high-speed stirring measure, the increased abundance of hydrogen-producing acetogens Synergistetes led to an increase in the abundance of Acidobacteria. Meanwhile, the concentration of acetic acid and propionic acid was increased by 21.09% and 6.44% respectively, and the abundance of hydrogenotrophic methanogens Methanocorpusculum was increased by 31.95%. Interestingly, the yield of methane had actually fallen. These data showed that excessive stirring during anaerobic digestion increased the concentrations of acetic acid and propionic acid significantly, and promoted the switchcover of methanogenic pathway from acetic acid pyrolysis pathway to less efficient acetic acid oxidation pathway. The results provided a new perspective for understanding the regulation between organic acid metabolism and methanogenic pathway in anaerobic digestion of pig manure.
2022, 50(8): 1269-1277
doi: 10.19756/j.issn.0253-3820.221172
Abstract:
A pair of cationic stable isotope labelling (SIL) probes, 4-trimethylaminobenzoyl hydrazide (HCTA) and its deuterated counterpart d3-HCTA, were designed and synthesized for labeling and ultra-high performance liquid chromatography-tandem triple quadrupole mass spectrometry (UPLC-MS/MS) analysis of α-dicarbonyl compounds. The labeled products were positively charged and thus the MS sensitivity was enhanced; the internal standard quantitative function of stable isotope labelling strategy effectively reduced the matrix effect and improved the method accuracy. The labeling conditions, chromatography and mass spectrometry parameters were optimized. The detection limits and recoveries of the method were 4.1-9.2 ng/L and 90.1%-95.3%, respectively. The cationic SIL probe was applied to the UPLC-MS/MS analysis of α-dicarbonyl compounds in food with satisfactory results.
A pair of cationic stable isotope labelling (SIL) probes, 4-trimethylaminobenzoyl hydrazide (HCTA) and its deuterated counterpart d3-HCTA, were designed and synthesized for labeling and ultra-high performance liquid chromatography-tandem triple quadrupole mass spectrometry (UPLC-MS/MS) analysis of α-dicarbonyl compounds. The labeled products were positively charged and thus the MS sensitivity was enhanced; the internal standard quantitative function of stable isotope labelling strategy effectively reduced the matrix effect and improved the method accuracy. The labeling conditions, chromatography and mass spectrometry parameters were optimized. The detection limits and recoveries of the method were 4.1-9.2 ng/L and 90.1%-95.3%, respectively. The cationic SIL probe was applied to the UPLC-MS/MS analysis of α-dicarbonyl compounds in food with satisfactory results.
