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2017 Volume 45 Issue 3
2017, 45(3): 303-308
doi: 10.11895/j.issn.0253-3820.160642
Abstract:
A highly sensitive and selective DNA biosensor is described based on the fluorescence quenching ability of MoS2 nanosheet and exonuclease Ⅲ (Exo Ⅲ) assisted dual-signal amplification. In this sensor, the fluorescence probes (HP1 and HP2) cannot be degraded by Exo Ⅲ due to the 3'-termini protrusion and thus are adsorbed on the surface of MoS2 nanosheets, which will result in the quenching of MoS2 nanosheets toward the probes and induce a low fluorescent signal. The presence of the target DNA leads to the desorption of probes on the surface of MoS2 nanosheets due to the hybridization toward probes, generating many fluorescent fragments by Exo Ⅲ digestion and inducing dual-signal amplification. This method can improve the sensitivity and detection limit compared with single amplification method, and shows excellent selectivity in the discrimination of single base mismatched targets. On the basis of the significantly high sensitivity, the developed biosensor can be potentially extended to detect various DNA targets with excellent sequence selectivity.
A highly sensitive and selective DNA biosensor is described based on the fluorescence quenching ability of MoS2 nanosheet and exonuclease Ⅲ (Exo Ⅲ) assisted dual-signal amplification. In this sensor, the fluorescence probes (HP1 and HP2) cannot be degraded by Exo Ⅲ due to the 3'-termini protrusion and thus are adsorbed on the surface of MoS2 nanosheets, which will result in the quenching of MoS2 nanosheets toward the probes and induce a low fluorescent signal. The presence of the target DNA leads to the desorption of probes on the surface of MoS2 nanosheets due to the hybridization toward probes, generating many fluorescent fragments by Exo Ⅲ digestion and inducing dual-signal amplification. This method can improve the sensitivity and detection limit compared with single amplification method, and shows excellent selectivity in the discrimination of single base mismatched targets. On the basis of the significantly high sensitivity, the developed biosensor can be potentially extended to detect various DNA targets with excellent sequence selectivity.
2017, 45(3): 309-315
doi: 10.11895/j.issn.0253-3820.160594
Abstract:
The analysis of stable nitrogen isotopic composition (δ15N) of individual amino acid was recognized as an effective method for estimating the trophic level of organisms and detecting the nitrogen flow in food webs. In this study, we evaluated a two-stage procedure of esterification followed by acylation, in which biological samples underwent hydrolysis in acid and the released individual amino acids were derivative into the corresponding N-pivaloyl-iso-propyl (NPP) esters for gas chromatography-combustion-isotope ratio mass spectrometric (GC-C-IRMS) analysis. A total of 13 kinds of individual amino acid derivatives were baseline separated on a nonpolar gas chromatography column (DB-5ms). The amount of sample for each test was not less than 20 ng N on column. High correlations were observed between the δ15N values respectively obtained by GC-C-IRMS and element analysis-isotope ration mass spectrometry (EA-IRMS). Furthermore, the mean precision of this method was better than 1‰. Cation-exchange chromatograph was used to purify the samples, and the difference of the detection δ15N values before and after purification by the resin was within 1‰. This method was applied to estimate the trophic level of various natural freshwater organisms from Aha Lake. The present study provided a new idea for the application of stable nitrogen isotope (δ15N) in the trophic level estimation of organisms and metabolism analysis of amino acid.
The analysis of stable nitrogen isotopic composition (δ15N) of individual amino acid was recognized as an effective method for estimating the trophic level of organisms and detecting the nitrogen flow in food webs. In this study, we evaluated a two-stage procedure of esterification followed by acylation, in which biological samples underwent hydrolysis in acid and the released individual amino acids were derivative into the corresponding N-pivaloyl-iso-propyl (NPP) esters for gas chromatography-combustion-isotope ratio mass spectrometric (GC-C-IRMS) analysis. A total of 13 kinds of individual amino acid derivatives were baseline separated on a nonpolar gas chromatography column (DB-5ms). The amount of sample for each test was not less than 20 ng N on column. High correlations were observed between the δ15N values respectively obtained by GC-C-IRMS and element analysis-isotope ration mass spectrometry (EA-IRMS). Furthermore, the mean precision of this method was better than 1‰. Cation-exchange chromatograph was used to purify the samples, and the difference of the detection δ15N values before and after purification by the resin was within 1‰. This method was applied to estimate the trophic level of various natural freshwater organisms from Aha Lake. The present study provided a new idea for the application of stable nitrogen isotope (δ15N) in the trophic level estimation of organisms and metabolism analysis of amino acid.
2017, 45(3): 316-321
doi: 10.11895/j.issn.0253-3820.160801
Abstract:
Endoproteinase Lys-C/trypsin sequential digestion and trypsin digestion were used in 293T cell proteomics sample preparation and the results of Lys-C/trypsin sequential digestion and trypsin digestion in proteomics sample preparation was systematically evaluated. It was found that the number of identified peptides and proteins increased significantly, and missed cleavage sites, especially K sites decreased dramatically through Lys-C/trypsin sequential digestion. And the average sequence coverage of identified proteins in Lys-C/trypsin sequential digestion sample was higher than that in trypsin digestion sample. Besides, different amount of enzymes was tested to select the optimal usage of enzymes in Lys-C/trypsin sequential digestion. This study provided the references for proteomics sample preparation.
Endoproteinase Lys-C/trypsin sequential digestion and trypsin digestion were used in 293T cell proteomics sample preparation and the results of Lys-C/trypsin sequential digestion and trypsin digestion in proteomics sample preparation was systematically evaluated. It was found that the number of identified peptides and proteins increased significantly, and missed cleavage sites, especially K sites decreased dramatically through Lys-C/trypsin sequential digestion. And the average sequence coverage of identified proteins in Lys-C/trypsin sequential digestion sample was higher than that in trypsin digestion sample. Besides, different amount of enzymes was tested to select the optimal usage of enzymes in Lys-C/trypsin sequential digestion. This study provided the references for proteomics sample preparation.
2017, 45(3): 322-330
doi: 10.11895/j.issn.0253-3820.160851
Abstract:
The whole protein extracts from tissue specimens (tumor and noncancerous) from patients with colorectal cancer were divided into several fractions with different molecular weight by gel electrophoresis, which were then subject to in-gel digestion and proteomics analysis by capillary liquid chromatography-mass spectrometry. A total of 29 differentially expressed proteins were identified, among which 19 were up-regulated proteins in tumor tissues, such as Fibrinogen beta chain, Vimentin, Fibrinogen gamma chain, Histone H2A type 1-B/E, Isoform 1 of Periostin, Fibrinogen alpha chain, Histone H3.1, Alpha-enolase, Protein disulfide-isomerase A3, and so on. Ten proteins were found to be down-regulated, including Sarcomeric tropomyosin kappa, Transgelin, Heat shock protein beta-1, Talin-1, Isoform 2 of Vinculin, Isoform 1 of Filamin-C, and so on. The differential expressions of Talin-1 and Alpha-enolase were selected to be verified by Western blot analysis. Bioinformatics analysis results indicated that most of the up-regulated proteins in colorectal cancer tissues had the feature of protein exocytosis, suggesting that these proteins were likely to penetrate into the circulatory system in the body, which could be detected in blood or ascites. On the other hand, most of the down-regulated proteins belonged to the cytoskeleton and extracellular matrix fibers, which were closely related to the invasion and metastasis of tumor cells into their surrounding tissues. This study provided basic data for the early diagnosis of colorectal cancer, colorectal cancer screening and other aspects, which had important significance to further study the pathogenesis of colorectal cancer.
The whole protein extracts from tissue specimens (tumor and noncancerous) from patients with colorectal cancer were divided into several fractions with different molecular weight by gel electrophoresis, which were then subject to in-gel digestion and proteomics analysis by capillary liquid chromatography-mass spectrometry. A total of 29 differentially expressed proteins were identified, among which 19 were up-regulated proteins in tumor tissues, such as Fibrinogen beta chain, Vimentin, Fibrinogen gamma chain, Histone H2A type 1-B/E, Isoform 1 of Periostin, Fibrinogen alpha chain, Histone H3.1, Alpha-enolase, Protein disulfide-isomerase A3, and so on. Ten proteins were found to be down-regulated, including Sarcomeric tropomyosin kappa, Transgelin, Heat shock protein beta-1, Talin-1, Isoform 2 of Vinculin, Isoform 1 of Filamin-C, and so on. The differential expressions of Talin-1 and Alpha-enolase were selected to be verified by Western blot analysis. Bioinformatics analysis results indicated that most of the up-regulated proteins in colorectal cancer tissues had the feature of protein exocytosis, suggesting that these proteins were likely to penetrate into the circulatory system in the body, which could be detected in blood or ascites. On the other hand, most of the down-regulated proteins belonged to the cytoskeleton and extracellular matrix fibers, which were closely related to the invasion and metastasis of tumor cells into their surrounding tissues. This study provided basic data for the early diagnosis of colorectal cancer, colorectal cancer screening and other aspects, which had important significance to further study the pathogenesis of colorectal cancer.
2017, 45(3): 331-335
doi: 10.11895/j.issn.0253-3820.160758
Abstract:
Spectrophotometric seawater pH measurement system is an urgent need of device due to its quick speed and high precision. Based on spectrophotometric method and flow injection analysis technique, an automated system for pH measurement of seawater was developed by integrating pump and valve flow path, LED light source, flow cell and spectrophotometer. This measurement system effectively avoided bubbles. The indicator of concentration gradient in the seawater sample was used to correct for the pH perturbation caused by the indicator, thus the operation of system was simple and convenient. With this system, only 1.5 min was needed for a sample measurement with a precision of 0.0013 pH units and an offset of 0.0059 pH units. This system could be used for the rapid determination of pH of seawater collected by laboratory or research ship with high precision pH values.
Spectrophotometric seawater pH measurement system is an urgent need of device due to its quick speed and high precision. Based on spectrophotometric method and flow injection analysis technique, an automated system for pH measurement of seawater was developed by integrating pump and valve flow path, LED light source, flow cell and spectrophotometer. This measurement system effectively avoided bubbles. The indicator of concentration gradient in the seawater sample was used to correct for the pH perturbation caused by the indicator, thus the operation of system was simple and convenient. With this system, only 1.5 min was needed for a sample measurement with a precision of 0.0013 pH units and an offset of 0.0059 pH units. This system could be used for the rapid determination of pH of seawater collected by laboratory or research ship with high precision pH values.
2017, 45(3): 336-341
doi: 10.11895/j.issn.0253-3820.160570
Abstract:
To improve the classification accuracy of fresh meat species using laser-induced breakdown spectroscopy (LIBS), the support vector machine (SVM) and principal component analysis (PCA) were combined to classify fresh meat species (including pork, beef, and chicken). A simple sample preparation to flatten fresh meat by glass slides was proposed. For each meat sample, 150 spectra were recorded and randomly arranged. The first 75 spectra were used to train a model while the others were used for model validation. By analyzing the 49 normalized spectral lines (K, Ca, Na, Mg, Al, H, O, etc.) in the different tissues, the classification model was built. The results showed that the dimensionality of input variables was decreased from 49 to 10 and modeling time was reduced from 89.11 s to 55.52 s using PCA, thus improving the modeling efficiency. The mean classification accuracy of 89.11% was achieved. The method and reference data are provided for further study of fresh meat classification by laser-induced breakdown spectroscopy technique.
To improve the classification accuracy of fresh meat species using laser-induced breakdown spectroscopy (LIBS), the support vector machine (SVM) and principal component analysis (PCA) were combined to classify fresh meat species (including pork, beef, and chicken). A simple sample preparation to flatten fresh meat by glass slides was proposed. For each meat sample, 150 spectra were recorded and randomly arranged. The first 75 spectra were used to train a model while the others were used for model validation. By analyzing the 49 normalized spectral lines (K, Ca, Na, Mg, Al, H, O, etc.) in the different tissues, the classification model was built. The results showed that the dimensionality of input variables was decreased from 49 to 10 and modeling time was reduced from 89.11 s to 55.52 s using PCA, thus improving the modeling efficiency. The mean classification accuracy of 89.11% was achieved. The method and reference data are provided for further study of fresh meat classification by laser-induced breakdown spectroscopy technique.
2017, 45(3): 342-347
doi: 10.11895/j.issn.0253-3820.160840
Abstract:
A preliminary method based on the laser resonance ionization mass spectrometer (LRIMS) developed in the laboratory was established to determine tin isotope ratios. By measuring the auto-ionization spectrum of tin atoms, a three-color-three-photon resonance ionization scheme was confirmed, and the laser wavelengths of each excitation/ionization step were λ1=286.4 nm, λ2=811.6 nm and λ3=823.7 nm. More effective electrothermal atomization of tin was implemented by mixing the samples and grapheme oxide solution, and the total detection efficiency of 1 μg of tin sample was above 3×10-5, which was about 4.5 times as high as the method of directly dropping samples. A tin-antimony-tellurium mixture at a ratio of 1:1:1 (m/m) was prepared as a simulant sample, and the major tin isotope ratios in the sample were determined. Results showed that the isobaric interference from antimony and tellurium was effectively avoided, and the relative standard deviations for 116Sn/120Sn, 117Sn/120Sn, 118Sn/120Sn, 119Sn/120Sn were all better than 1%. This work indicated that LRIMS could effectively avoid the isobaric interference in the measurement of tin isotope ratios, and could be applied to measure the fission product 121mSn and 126Sn in the reactor spent fuel.
A preliminary method based on the laser resonance ionization mass spectrometer (LRIMS) developed in the laboratory was established to determine tin isotope ratios. By measuring the auto-ionization spectrum of tin atoms, a three-color-three-photon resonance ionization scheme was confirmed, and the laser wavelengths of each excitation/ionization step were λ1=286.4 nm, λ2=811.6 nm and λ3=823.7 nm. More effective electrothermal atomization of tin was implemented by mixing the samples and grapheme oxide solution, and the total detection efficiency of 1 μg of tin sample was above 3×10-5, which was about 4.5 times as high as the method of directly dropping samples. A tin-antimony-tellurium mixture at a ratio of 1:1:1 (m/m) was prepared as a simulant sample, and the major tin isotope ratios in the sample were determined. Results showed that the isobaric interference from antimony and tellurium was effectively avoided, and the relative standard deviations for 116Sn/120Sn, 117Sn/120Sn, 118Sn/120Sn, 119Sn/120Sn were all better than 1%. This work indicated that LRIMS could effectively avoid the isobaric interference in the measurement of tin isotope ratios, and could be applied to measure the fission product 121mSn and 126Sn in the reactor spent fuel.
2017, 45(3): 348-356
doi: 10.11895/j.issn.0253-3820.160699
Abstract:
Phthalic acid esters (PAEs) are one class of the most important plasticizers which are widely used in the production of plastic products. The accurate analysis of PAEs in seawater and sediment would be of great significance to study the transformation of PAEs and their ecological effects in marine environment. In this study, the method of gas chromatography with mass spectrum detector (GC-MSD) coupled with solid-phase microextraction had been established to analyze the concentration of PAEs in seawater and sediment, and various experimental conditions such as extraction time and extraction temperature were optimized. Under the optimum conditions, the precision was less than 10.0%, and the limits of detection were 0.04-0.32 μg/L and 0.12-1.60 μg/kg. Except dimethyl phthalate (DMP), the recovery of PAEs in seawater and sediment ranged from 68.0% to 114.0% and 76.4% to 105.0%, respectively. Moreover, the concentrations of PAEs measured with the method were 0.270-1.39 μg/L and 0.74-34.8 μg/kg in seawater and sediment samples of Changjiang River Estuary and its adjacent area, respectively. In conclusion, the analytical method is easy to operate and reduces the extraction volume of seawater water, thus it meets the requirements of the analysis of PAEs in coastal seawater and sediment.
Phthalic acid esters (PAEs) are one class of the most important plasticizers which are widely used in the production of plastic products. The accurate analysis of PAEs in seawater and sediment would be of great significance to study the transformation of PAEs and their ecological effects in marine environment. In this study, the method of gas chromatography with mass spectrum detector (GC-MSD) coupled with solid-phase microextraction had been established to analyze the concentration of PAEs in seawater and sediment, and various experimental conditions such as extraction time and extraction temperature were optimized. Under the optimum conditions, the precision was less than 10.0%, and the limits of detection were 0.04-0.32 μg/L and 0.12-1.60 μg/kg. Except dimethyl phthalate (DMP), the recovery of PAEs in seawater and sediment ranged from 68.0% to 114.0% and 76.4% to 105.0%, respectively. Moreover, the concentrations of PAEs measured with the method were 0.270-1.39 μg/L and 0.74-34.8 μg/kg in seawater and sediment samples of Changjiang River Estuary and its adjacent area, respectively. In conclusion, the analytical method is easy to operate and reduces the extraction volume of seawater water, thus it meets the requirements of the analysis of PAEs in coastal seawater and sediment.
2017, 45(3): 357-362
doi: 10.11895/j.issn.0253-3820.160734
Abstract:
Reduced graphene oxide-BiPO4 (RGO-BiPO4) nanocomposite was synthesized successfully via a one-pot solvothermal method using graphene oxide and bismuth nitrate as precursors and glycerin as solvent at 200℃ for 1 h. The morphology and structure of as-prepared nanocomposite were characterized by SEM, TEM, XRD, XPS, SERS and UV-Visible spectrum. The photocatalytic activity of the nanocomposite was evaluated by the photodegradation of Rhodamine B (RhB) dye under UV irradiation and it was found that RGO-BiPO4 nanocomposite possessed higher photocatalytic activity than that of pure BiPO4. RhB could be decomposed 87.5% within 2 h. Under the same conditions, only 45.7% of the RhB dye could be decomposed by BiPO4. The enhancement of photocatalytic activity could be attributed to the effective charge separation due to the electron-accepting and transporting properties of graphene.
Reduced graphene oxide-BiPO4 (RGO-BiPO4) nanocomposite was synthesized successfully via a one-pot solvothermal method using graphene oxide and bismuth nitrate as precursors and glycerin as solvent at 200℃ for 1 h. The morphology and structure of as-prepared nanocomposite were characterized by SEM, TEM, XRD, XPS, SERS and UV-Visible spectrum. The photocatalytic activity of the nanocomposite was evaluated by the photodegradation of Rhodamine B (RhB) dye under UV irradiation and it was found that RGO-BiPO4 nanocomposite possessed higher photocatalytic activity than that of pure BiPO4. RhB could be decomposed 87.5% within 2 h. Under the same conditions, only 45.7% of the RhB dye could be decomposed by BiPO4. The enhancement of photocatalytic activity could be attributed to the effective charge separation due to the electron-accepting and transporting properties of graphene.
2017, 45(3): 363-368
doi: 10.11895/j.issn.0253-3820.160773
Abstract:
A near infrared spectroscopy (NIRS) method was used for rapid quality evaluation of ferulic acid content in chrysanthemum morifolium cv. (Chuju) continuous cropping soil. Standard leverage, studentized residual and Mahalanobis distance were calculated to eliminate abnormal samples. After the initial near infrared spectrum was treated by two second derivative and Norris smoothing filter noise, 6000-4000 cm-1 wave number range and 7 factors were chosen for partial least squares (PLS) calibration model. The results showed that good correlation was presented between the calibration set/validation set and the values determined by high performance liquid chromatography, and the calibration correlation coefficient (Rc) and validation correlation coefficient (Rcv) were 0.9914 and 0.9935, respectively. Root mean square error of calibration (RMSEC), root mean square error of validation (RMSEP) and root mean square error of cross-validation (RMSECV) were 0.484, 0.539 and 0.615, respectively. This method was accurate, reliable, simple, rapid and nondestructive, and could be applied to the fast analysis for ferulic acid in continuous cropping soil.
A near infrared spectroscopy (NIRS) method was used for rapid quality evaluation of ferulic acid content in chrysanthemum morifolium cv. (Chuju) continuous cropping soil. Standard leverage, studentized residual and Mahalanobis distance were calculated to eliminate abnormal samples. After the initial near infrared spectrum was treated by two second derivative and Norris smoothing filter noise, 6000-4000 cm-1 wave number range and 7 factors were chosen for partial least squares (PLS) calibration model. The results showed that good correlation was presented between the calibration set/validation set and the values determined by high performance liquid chromatography, and the calibration correlation coefficient (Rc) and validation correlation coefficient (Rcv) were 0.9914 and 0.9935, respectively. Root mean square error of calibration (RMSEC), root mean square error of validation (RMSEP) and root mean square error of cross-validation (RMSECV) were 0.484, 0.539 and 0.615, respectively. This method was accurate, reliable, simple, rapid and nondestructive, and could be applied to the fast analysis for ferulic acid in continuous cropping soil.
2017, 45(3): 369-373
doi: 10.11895/j.issn.0253-3820.160731
Abstract:
A reversed phase high performance liquid chromatographic (RP-HPLC) method was proposed by using C18 column tandem crown ether chiral column for simultaneous separation of three kinds of aromatic amino acid enantiomers. The chromatographic conditions, including mobile phase proportion, pH, column temperature and flow rate, were optimized. The experimental results showed that the three aromatic amino acid enantiomers could be successfully separated under the optimal conditions such as perchloric acid solution-acetonitrile (86:14, V/V, pH=2) as mobile phase, column temperature of 20℃ and flow rate of 0.4 mL/min. The separation under four HPLC column connection modes was further investigated. The results revealed that different kinds of amino acids could be separated on C18 column, but not for amino acid enantiomers; amino acid enantiomers could be separated on crown ether chiral column, but the chromatographic peaks of each amino acid enantiomers overlapped seriously; baseline separation of three amino acid enantiomers could be obtained under the connection of two columns, but the separation under different column connection sequence almost had no difference except the peak shape.
A reversed phase high performance liquid chromatographic (RP-HPLC) method was proposed by using C18 column tandem crown ether chiral column for simultaneous separation of three kinds of aromatic amino acid enantiomers. The chromatographic conditions, including mobile phase proportion, pH, column temperature and flow rate, were optimized. The experimental results showed that the three aromatic amino acid enantiomers could be successfully separated under the optimal conditions such as perchloric acid solution-acetonitrile (86:14, V/V, pH=2) as mobile phase, column temperature of 20℃ and flow rate of 0.4 mL/min. The separation under four HPLC column connection modes was further investigated. The results revealed that different kinds of amino acids could be separated on C18 column, but not for amino acid enantiomers; amino acid enantiomers could be separated on crown ether chiral column, but the chromatographic peaks of each amino acid enantiomers overlapped seriously; baseline separation of three amino acid enantiomers could be obtained under the connection of two columns, but the separation under different column connection sequence almost had no difference except the peak shape.
2017, 45(3): 374-380
doi: 10.11895/j.issn.0253-3820.160785
Abstract:
The facile and efficient synthetic route for Ag dendritic nanostructures on Indium tin oxide (ITO) via electrodeposition was reported. The results showed that the Raman intensities of rhodamine 6G (R6G) decreased with decreasing the loading concentration, and even at a low concentration of 10-10 mol/L, the signatures of R6G in Raman spectrum were still clearly observed. It indicated that the Ag dendritic nanostructures exhibited high surface-enhanced Raman scattering (SERS) sensitivity. Moreover, the relative standard deviation (RSD) of band at 610 cm-1 was calculated to be 12.1%, 12.0%, 11.7%, 10.9%, 13.2% and 14.3%, respectively, corresponding with the concentration of R6G from 10-5 mol/L to 10-10 mol/L, which revealed that the Ag dendritic nanostructures could provide abundant hot spots and exhibited excellent reproducibility. In addition, the SERS spectrum of 3-mercaptopropionic acid (3MPA) also could be detected when its concentration was 10-5 mol/L. This method offers an easy and low-cost way to prepare Ag dendritic substrates and makes SERS detection more practicable.
The facile and efficient synthetic route for Ag dendritic nanostructures on Indium tin oxide (ITO) via electrodeposition was reported. The results showed that the Raman intensities of rhodamine 6G (R6G) decreased with decreasing the loading concentration, and even at a low concentration of 10-10 mol/L, the signatures of R6G in Raman spectrum were still clearly observed. It indicated that the Ag dendritic nanostructures exhibited high surface-enhanced Raman scattering (SERS) sensitivity. Moreover, the relative standard deviation (RSD) of band at 610 cm-1 was calculated to be 12.1%, 12.0%, 11.7%, 10.9%, 13.2% and 14.3%, respectively, corresponding with the concentration of R6G from 10-5 mol/L to 10-10 mol/L, which revealed that the Ag dendritic nanostructures could provide abundant hot spots and exhibited excellent reproducibility. In addition, the SERS spectrum of 3-mercaptopropionic acid (3MPA) also could be detected when its concentration was 10-5 mol/L. This method offers an easy and low-cost way to prepare Ag dendritic substrates and makes SERS detection more practicable.
2017, 45(3): 381-388
doi: 10.11895/j.issn.0253-3820.160633
Abstract:
An ultra-high performance liquid chromatography-mass spectrometry (UPLC-MS/MS) method was developed for the determination of 8 kinds of cephalosporins, cefoperazone, cefquinome, cefalonium, cefazolin, cefapirin, Ceftiofur, cefpirome and cefalexin, in edible parts of aquatic products. The samples were extracted with acetonitrile-water and cleaned up by multi-walled carbon nanotubes (MWCNTs) SPE cartridge. All the target compounds were separated on an Acquity Xselect CSH C18 column with gradient elution by using acetonitrile and 0.1% formic acid aqueous as eluent, and detected by UPLC-MS/MS under ESI+ ionization and MRM mode. Under optimized conditions, this method had a good linearity (R2≥0.995) and the limits of quantification were in the range of 2-10 μg/kg (S/N=10). The recoveries of the method for the target compounds spiked at three different levels were 67.3%-94.2% with the relative standard deviations (RSDs) of 3.3%-14%. The method had the characteristics of low cost, high accuracy and good precision, and could meet the requirements of cephalosporins determination.
An ultra-high performance liquid chromatography-mass spectrometry (UPLC-MS/MS) method was developed for the determination of 8 kinds of cephalosporins, cefoperazone, cefquinome, cefalonium, cefazolin, cefapirin, Ceftiofur, cefpirome and cefalexin, in edible parts of aquatic products. The samples were extracted with acetonitrile-water and cleaned up by multi-walled carbon nanotubes (MWCNTs) SPE cartridge. All the target compounds were separated on an Acquity Xselect CSH C18 column with gradient elution by using acetonitrile and 0.1% formic acid aqueous as eluent, and detected by UPLC-MS/MS under ESI+ ionization and MRM mode. Under optimized conditions, this method had a good linearity (R2≥0.995) and the limits of quantification were in the range of 2-10 μg/kg (S/N=10). The recoveries of the method for the target compounds spiked at three different levels were 67.3%-94.2% with the relative standard deviations (RSDs) of 3.3%-14%. The method had the characteristics of low cost, high accuracy and good precision, and could meet the requirements of cephalosporins determination.
2017, 45(3): 389-396
doi: 10.11895/j.issn.0253-3820.160753
Abstract:
An untargeted urinary metabonomics method based on ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) has been established to investigate the mechanism of Schisandra chinensis in treating diabetes and its complications. The urinary biomarkers related to the therapeutic effects of Schisandra chinensis on the diabetes rats were analyzed. In urine, 28 kinds of endogenous metabolites were identified as potential biomarkers, including 13 endogenous metabolites in positive ion mode, 15 endogenous metabolites in negative ion mode, and hippuric acid detected both in positive and negative ion modes. The results revealed that Schisandra chinensis mainly affected the pathways of pentose and glucuronate interconversions, riboflavin metabolism, pantothenate and CoA biosynthesis, arginine and proline metabolism, intestinal bacteria metabolism, ascorbate and aldarate metabolism and tryptophan metabolism in diabetic rats. Combined with biological analysis of these pathways, the therapeutic mechanism of Schisandra chinensis on diabetes and its complications was verified. Based on the biological function of each pathway, the effect of Schisandra chinensis on diabetic nephropathy is stronger. Moreover, it also has the effects of protecting liver, decreasing fat and antioxidant activity.
An untargeted urinary metabonomics method based on ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) has been established to investigate the mechanism of Schisandra chinensis in treating diabetes and its complications. The urinary biomarkers related to the therapeutic effects of Schisandra chinensis on the diabetes rats were analyzed. In urine, 28 kinds of endogenous metabolites were identified as potential biomarkers, including 13 endogenous metabolites in positive ion mode, 15 endogenous metabolites in negative ion mode, and hippuric acid detected both in positive and negative ion modes. The results revealed that Schisandra chinensis mainly affected the pathways of pentose and glucuronate interconversions, riboflavin metabolism, pantothenate and CoA biosynthesis, arginine and proline metabolism, intestinal bacteria metabolism, ascorbate and aldarate metabolism and tryptophan metabolism in diabetic rats. Combined with biological analysis of these pathways, the therapeutic mechanism of Schisandra chinensis on diabetes and its complications was verified. Based on the biological function of each pathway, the effect of Schisandra chinensis on diabetic nephropathy is stronger. Moreover, it also has the effects of protecting liver, decreasing fat and antioxidant activity.
2017, 45(3): 397-402
doi: 10.11895/j.issn.0253-3820.160784
Abstract:
In the presence of silver ion, Mn2+ could be electro-oxidized to potassium hypermanganate in phosphoric acid solution, which could effectively react with pyrocatechol in acid solution and luminol in sodium hydroxide solution to produce chemiluminescence. On the basis of this, a novel indirect approach for the detection of Mn2+ was established. The effect of silver ions on the electrochemical oxidation of Mn2+ was studied. When 1.5×10-5 mol/L Ag+ and 0.01 mol/L phosphoric acid solution were used in the process of electrochemical oxidation, the CL intensity could be up to the maximum value after the above solution was electrolyzed for 2 min. The relation of CL intensity and Mn2+ concentration in the solutions at different pH and the selectivity were also investigated. When the pyrocatechol was used as luminescent reagent in the acidic medium, the CL intensity was linearly to the Mn2+ concentration in the range of 1.82×10-7-7.27×10-5 mol/L with excellent selectivity. Common ions had little interferences in the determination of Mn2+. The method was successfully applied to the determination of Mn2+ in surface water and drinking water with satisfactory results.
In the presence of silver ion, Mn2+ could be electro-oxidized to potassium hypermanganate in phosphoric acid solution, which could effectively react with pyrocatechol in acid solution and luminol in sodium hydroxide solution to produce chemiluminescence. On the basis of this, a novel indirect approach for the detection of Mn2+ was established. The effect of silver ions on the electrochemical oxidation of Mn2+ was studied. When 1.5×10-5 mol/L Ag+ and 0.01 mol/L phosphoric acid solution were used in the process of electrochemical oxidation, the CL intensity could be up to the maximum value after the above solution was electrolyzed for 2 min. The relation of CL intensity and Mn2+ concentration in the solutions at different pH and the selectivity were also investigated. When the pyrocatechol was used as luminescent reagent in the acidic medium, the CL intensity was linearly to the Mn2+ concentration in the range of 1.82×10-7-7.27×10-5 mol/L with excellent selectivity. Common ions had little interferences in the determination of Mn2+. The method was successfully applied to the determination of Mn2+ in surface water and drinking water with satisfactory results.
2017, 45(3): 403-408
doi: 10.11895/j.issn.0253-3820.160730
Abstract:
An enhanced gold immunochromatographic assay (GICA) with simplicity, rapidity and high sensitivity was developed to detect imidaclothiz by using the high affinity between biotin and streptavidin. The 13-nm AuNPs were double-labeled with anti-imidaclothiz antibody and biotinylated DNA, and the 41-nm AuNPs were labeled with streptavidin to prepare an enhanced gold immunochromatographic test strip for imidaclothiz. The working conditions of the strip were systematically optimized, and the sensitivity, specificity, precision and accuracy were assessed by testing the cross-reactivity (CR), spiked recovery and validation with high performance liquid chromatography (HPLC). Under the optimal conditions, the detection could be completed in 10 min with visual result, and the limit of detection (LOD) was 25 ng/mL. The analysis showed no cross-reactivity with analogues of imidaclothiz except for imidacloprid. The detection results of GICA agreed with the spiked concentrations of imidaclothiz at spiked levels of 0.05, 0.5 and 5 μg/g in river water, rice, cucumber, tomato, pear, cabbage and apple samples. The detection results of GICA for imidaclothiz in unknown concentration river water and pear samples were consistent with that of HPLC.
An enhanced gold immunochromatographic assay (GICA) with simplicity, rapidity and high sensitivity was developed to detect imidaclothiz by using the high affinity between biotin and streptavidin. The 13-nm AuNPs were double-labeled with anti-imidaclothiz antibody and biotinylated DNA, and the 41-nm AuNPs were labeled with streptavidin to prepare an enhanced gold immunochromatographic test strip for imidaclothiz. The working conditions of the strip were systematically optimized, and the sensitivity, specificity, precision and accuracy were assessed by testing the cross-reactivity (CR), spiked recovery and validation with high performance liquid chromatography (HPLC). Under the optimal conditions, the detection could be completed in 10 min with visual result, and the limit of detection (LOD) was 25 ng/mL. The analysis showed no cross-reactivity with analogues of imidaclothiz except for imidacloprid. The detection results of GICA agreed with the spiked concentrations of imidaclothiz at spiked levels of 0.05, 0.5 and 5 μg/g in river water, rice, cucumber, tomato, pear, cabbage and apple samples. The detection results of GICA for imidaclothiz in unknown concentration river water and pear samples were consistent with that of HPLC.
2017, 45(3): 409-415
doi: 10.11895/j.issn.0253-3820.160724
Abstract:
A novel electrochemiluminescence (ECL) method for the determination of L-cysteine (L-Cys) was established. Water-soluble CdS quantum dots (QDs) with Cd2+ rich surface were synthesized via a controllable one-poe approach. The mercapto group in L-cysteine molecule can specifically interact with excessive Cd2+ on the surface of CdS QDs, resulting in enhancement of ECL intensity of the CdS QDs, which can be used for the detection of L-Cys. Under the optimal experimental conditions, the enhancement of ECL intensity was linear with the concentration of L-Cys in the range of 5.0×10-9-1.0×10-5 mol/L. The limit detection of (S/N=3) was 1.2×10-9 mol/L. In comparison with other methods for detecting L-Cys, this method is more simple and selective, and can be applied to detect L-Cys in real sample with satisfactory results.
A novel electrochemiluminescence (ECL) method for the determination of L-cysteine (L-Cys) was established. Water-soluble CdS quantum dots (QDs) with Cd2+ rich surface were synthesized via a controllable one-poe approach. The mercapto group in L-cysteine molecule can specifically interact with excessive Cd2+ on the surface of CdS QDs, resulting in enhancement of ECL intensity of the CdS QDs, which can be used for the detection of L-Cys. Under the optimal experimental conditions, the enhancement of ECL intensity was linear with the concentration of L-Cys in the range of 5.0×10-9-1.0×10-5 mol/L. The limit detection of (S/N=3) was 1.2×10-9 mol/L. In comparison with other methods for detecting L-Cys, this method is more simple and selective, and can be applied to detect L-Cys in real sample with satisfactory results.
2017, 45(3): 416-422
doi: 10.11895/j.issn.0253-3820.160685
Abstract:
A method of complete acid hydrolysis combined with high performance anion exchange chromatography and pulsed amperometric detection was developed for the monosaccharide composition analysis of arabinoxylan from the seeds of plantago asiatica L. The parameters including hydrolysis methods, acid types, acid concentration, hydrolysis temperature, hydrolysis time and placement time, which would affect the hydrolysis process, were optimized. The results showed that it would have a better hydrolysis effect for polysaccharide from the seeds of Plantago asiatica L. with 2 mol/L H2SO4 in an atmospheric oil bath at 120℃ for 2 hours. However, the placement time for diluted solution of the hydrolyzed polysaccharide should be less than 6 hours. The polysaccharide was mainly composed of Arabinose (8.89%) and Xylose (41.52%) and Galacturonic acid (0.73%). Glcuronic acid (3.44%) was detected simultaneously, and there were also trace amounts of Galatose and Glucose. The results were reproducible. Other arabinoxylans from Panicummiliaceum L. shell, Avena sativa L. bran and Hordeum vulgare L. were taken for monosaccharide compositions analysis under the optimal hydrolysis conditions and the analysis results were good. This study would provide a good reference for monosaccharides composition analysis of arabinoxylans from various sources.
A method of complete acid hydrolysis combined with high performance anion exchange chromatography and pulsed amperometric detection was developed for the monosaccharide composition analysis of arabinoxylan from the seeds of plantago asiatica L. The parameters including hydrolysis methods, acid types, acid concentration, hydrolysis temperature, hydrolysis time and placement time, which would affect the hydrolysis process, were optimized. The results showed that it would have a better hydrolysis effect for polysaccharide from the seeds of Plantago asiatica L. with 2 mol/L H2SO4 in an atmospheric oil bath at 120℃ for 2 hours. However, the placement time for diluted solution of the hydrolyzed polysaccharide should be less than 6 hours. The polysaccharide was mainly composed of Arabinose (8.89%) and Xylose (41.52%) and Galacturonic acid (0.73%). Glcuronic acid (3.44%) was detected simultaneously, and there were also trace amounts of Galatose and Glucose. The results were reproducible. Other arabinoxylans from Panicummiliaceum L. shell, Avena sativa L. bran and Hordeum vulgare L. were taken for monosaccharide compositions analysis under the optimal hydrolysis conditions and the analysis results were good. This study would provide a good reference for monosaccharides composition analysis of arabinoxylans from various sources.
2017, 45(3): 423-428
doi: 10.11895/j.issn.0253-3820.160656
Abstract:
A co-analysis method of gas chromatography coupled to a triple quadrupole mass spectrometry (GC-MS/MS) was developed for the determination of 11 kinds of Dechlorane plus (DP) related compounds, including DPs, dechlorinated DPs and its structural analogs. This method was successfully applied to the analysis of DPs in field soil samples. After clean-up through a multi-layer silica/aluminum column, the soil sample concentrate was measured with the following instrumental parameters:electron impact ion source, select reaction monitoring mode, DB-5HT capillary column (15 m×0.25 mm i. d., 0.1 μm), and temperatures for injection port, transfer line and ion source were 260℃, 280℃ and 250℃, respectively. About 1 μL of sample was injected in splitless mode with helium at 1.5 mL/min as carrier gas. The results showed that the analyte standard curves demonstrated linearity of 4 or 5 magnitude ranges with the correlation coefficient varying between 0.9977 and 0.9999. The instrumental detection limits for these analytes were in the range of 0.005-0.100 pg, and the relative standard deviations (RSDs) for 5 parallel analyses at concentration level of 50 pg/μL were 1.1%-19.8%. With this method, the total concentrations of DP and related compounds in the field soil samples from a typical polluted site and its surrounding area changed between 0.275 and 681 ng/g dw (dry weight) with a detection rate of 100%, and the concentrations for individual analyte varied from n.d. to 537 ng/g dw with anti-DP and syn-DP as the dominant pollutants. The mean recoveries of the two surrogate standards in all samples were 55.0%-103.0% and 83.4%-107.0%, respectively, and the mean recoveries and RSDs of all analytes in blank and matrix samples were 53.9%-117.0% and 6.0%-19.1%, respectively.
A co-analysis method of gas chromatography coupled to a triple quadrupole mass spectrometry (GC-MS/MS) was developed for the determination of 11 kinds of Dechlorane plus (DP) related compounds, including DPs, dechlorinated DPs and its structural analogs. This method was successfully applied to the analysis of DPs in field soil samples. After clean-up through a multi-layer silica/aluminum column, the soil sample concentrate was measured with the following instrumental parameters:electron impact ion source, select reaction monitoring mode, DB-5HT capillary column (15 m×0.25 mm i. d., 0.1 μm), and temperatures for injection port, transfer line and ion source were 260℃, 280℃ and 250℃, respectively. About 1 μL of sample was injected in splitless mode with helium at 1.5 mL/min as carrier gas. The results showed that the analyte standard curves demonstrated linearity of 4 or 5 magnitude ranges with the correlation coefficient varying between 0.9977 and 0.9999. The instrumental detection limits for these analytes were in the range of 0.005-0.100 pg, and the relative standard deviations (RSDs) for 5 parallel analyses at concentration level of 50 pg/μL were 1.1%-19.8%. With this method, the total concentrations of DP and related compounds in the field soil samples from a typical polluted site and its surrounding area changed between 0.275 and 681 ng/g dw (dry weight) with a detection rate of 100%, and the concentrations for individual analyte varied from n.d. to 537 ng/g dw with anti-DP and syn-DP as the dominant pollutants. The mean recoveries of the two surrogate standards in all samples were 55.0%-103.0% and 83.4%-107.0%, respectively, and the mean recoveries and RSDs of all analytes in blank and matrix samples were 53.9%-117.0% and 6.0%-19.1%, respectively.
2017, 45(3): 429-433
doi: 10.11895/j.issn.0253-3820.160860
Abstract:
The front-face fluorescence spectrometry was developed for determination of migration amount of fluorescent whitening agents in washing products. The glass fiber paper was used as the adsorbent. The fluorescent whitening agents in washing products could be adsorbed onto the adsorbent. The adsorbent was directly measured with a self-assembly front-face fluorescence spectrometer. The linear range for the determination of fluorescent whitening agents was 10.0-500.0 μg/kg, and the limit of detection was 2.8 μg/kg. Ninety-six kinds of washing products were analyzed and the migration amounts of the whitening agents in 12 kinds of washing products were detectable. The correlation of analytical results of the 96 samples obtained by the present method with these obtained by the visual colorimestry was satisfactory. The present method was simple, rapid, and accurate and could be applied to the determination of the migration amount of the fluorescent whitening agents in the washing products.
The front-face fluorescence spectrometry was developed for determination of migration amount of fluorescent whitening agents in washing products. The glass fiber paper was used as the adsorbent. The fluorescent whitening agents in washing products could be adsorbed onto the adsorbent. The adsorbent was directly measured with a self-assembly front-face fluorescence spectrometer. The linear range for the determination of fluorescent whitening agents was 10.0-500.0 μg/kg, and the limit of detection was 2.8 μg/kg. Ninety-six kinds of washing products were analyzed and the migration amounts of the whitening agents in 12 kinds of washing products were detectable. The correlation of analytical results of the 96 samples obtained by the present method with these obtained by the visual colorimestry was satisfactory. The present method was simple, rapid, and accurate and could be applied to the determination of the migration amount of the fluorescent whitening agents in the washing products.
2017, 45(3): 434-440
doi: 10.11895/j.issn.0253-3820.160651
Abstract:
An ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed and validated for the simultaneous determination of 9 kinds of trace endocrine disrupting chemicals in biological samples using ultrasonic-assisted extraction followed by purification with gel permeation chromatography (GPC) and silica gel columns. The sample extracts were purified by Bio beads S-X3 GPC columns with cyclohexane/ethyl acetate (1:1, V/V) as mobile phase, and the target compounds were eluted in the fraction of 12-28 mL retention volume. Electrospray ionization source operated in positive mode and atmospheric pressure chemical ionization source operated in negative mode were used for mass spectrometric detection. Data acquisition was carried out in multiple reaction monitoring mode. Recoveries were predominately within 65.2%-118.0%. Method quantification limits were 0.1-9.7 ng/g dw (dry weight). This method was successfully applied to the analysis of the target endocrine disrupting chemicals in carps collected from the Pearl River. With the exception of carbanilide and triclocarban, the rest analytes were detected in fish tissue samples, with the concentrations varied within the range of 0.1-22.6 ng/g dw.
An ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed and validated for the simultaneous determination of 9 kinds of trace endocrine disrupting chemicals in biological samples using ultrasonic-assisted extraction followed by purification with gel permeation chromatography (GPC) and silica gel columns. The sample extracts were purified by Bio beads S-X3 GPC columns with cyclohexane/ethyl acetate (1:1, V/V) as mobile phase, and the target compounds were eluted in the fraction of 12-28 mL retention volume. Electrospray ionization source operated in positive mode and atmospheric pressure chemical ionization source operated in negative mode were used for mass spectrometric detection. Data acquisition was carried out in multiple reaction monitoring mode. Recoveries were predominately within 65.2%-118.0%. Method quantification limits were 0.1-9.7 ng/g dw (dry weight). This method was successfully applied to the analysis of the target endocrine disrupting chemicals in carps collected from the Pearl River. With the exception of carbanilide and triclocarban, the rest analytes were detected in fish tissue samples, with the concentrations varied within the range of 0.1-22.6 ng/g dw.
2017, 45(3): 441-447
doi: 10.11895/j.issn.0253-3820.160766
Abstract:
A method of ultra performance liquid chromatography-quadrupole-time of flight-mass spectrometry (UPLC-Q-TOF MS) was developed to determine 35 kinds of illegally added chemical fungicides in pesticide formulations. The samples were pretreated based on the ultrasonic extraction by the solvent of methanol, and then separated on a Zorbax C18 (100 mm×1.8 mm, 2.1 μm) column by a gradient elution with 0.1% formic acid aqueous solution and acetonitrile as the mobile phase. The mass spectrometer was operated under positive mode. Under the optimal conditions, the recoveries at three spiked levels (0.2, 0.4, and 2.0 mg/kg) were in the range of 81.0%-101.3% and the RSDs were 1.0%-4.4%. Based on the developed method, 100 samples were analyzed, and among which 6 samples were screened out chemical fungicides. The proposed method was high-efficient, accurate and reliable for the qualitatively screening of illegaly added chemical fungicides.
A method of ultra performance liquid chromatography-quadrupole-time of flight-mass spectrometry (UPLC-Q-TOF MS) was developed to determine 35 kinds of illegally added chemical fungicides in pesticide formulations. The samples were pretreated based on the ultrasonic extraction by the solvent of methanol, and then separated on a Zorbax C18 (100 mm×1.8 mm, 2.1 μm) column by a gradient elution with 0.1% formic acid aqueous solution and acetonitrile as the mobile phase. The mass spectrometer was operated under positive mode. Under the optimal conditions, the recoveries at three spiked levels (0.2, 0.4, and 2.0 mg/kg) were in the range of 81.0%-101.3% and the RSDs were 1.0%-4.4%. Based on the developed method, 100 samples were analyzed, and among which 6 samples were screened out chemical fungicides. The proposed method was high-efficient, accurate and reliable for the qualitatively screening of illegaly added chemical fungicides.
2017, 45(3): 448-454
doi: 10.11895/j.issn.0253-3820.160745
Abstract:
A high-throughput method is established to determine 25-hydroxyvitamin D2[25(OH)D2] and 25-hydroxyvitamin D3[25(OH)D3] in dried blood spots (DBS) by liquid chromatography-tandem mass spectrometry (LC-MS/MS), which only needs a DBS sample prepared from about 6 μL of whole blood. The DBS sample processing includes ultrasonic extraction of analytes, addition of 25(OH)D2-D6 and 25(OH)D3-D3 as internal standard, application of 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD) as derivatization reagent. The procedure is carried out in a 96-well plate format in an automated liquid handling platform to facilitate high-throughput analysis. The processed sample is separated in a C18 column with water-methanol gradient elution, and quantitated by mass spectrometry in multiple reaction monitoring (MRM) mode. For both 25(OH)D2 and 25(OH)D3, the linear range of quantitation is 0.94-120 ng/mL, the limit of detection is 0.12 ng/mL (S/N=3), and the limit of quantitation is 0.94 ng/mL (S/N=10). The intra-day relative standard deviation (RSD) values of 25(OH)D2 and 25(OH)D3 are 1.4%-6.6%, 3.7%-7.0%, respectively. The inter-day RSD values of 25(OH)D2 and 25(OH)D3 are 4.0%-5.3%, 3.8-10.6%, respectively. The recovery (mean±SD) in 5 consecutive of 25(OH)D2 is 98.7%±4.6%-108.5%±6.5%, and that of 25(OH)D3 is 94.8%±6.8%-101.3%±2.9%. DBS sample stability is confirmed by measuring identical DBS samples stored for 0, 1, 2, 3, 5, 7 and 14 days at -20℃, 22℃, and 37℃, and an overall RSD<15% was observed under each temperature. DBS sample stability in freeze-thaw cycles is also confirmed by experimenting identical DBS samples up to 14 free-thaw cycles (each cycle consisting of 23 h freezing at -80℃ followed by 1 h thaw at room temperature), and an overall RSD<15% is observed. The accuracy of 25(OH)D2 and 25(OH)D3 quantitation is validated by measuring a DBS sample prepared from NIST reference material SRM972a Level 3 and the recovery is found to be 110.3% and 103.0%.
A high-throughput method is established to determine 25-hydroxyvitamin D2[25(OH)D2] and 25-hydroxyvitamin D3[25(OH)D3] in dried blood spots (DBS) by liquid chromatography-tandem mass spectrometry (LC-MS/MS), which only needs a DBS sample prepared from about 6 μL of whole blood. The DBS sample processing includes ultrasonic extraction of analytes, addition of 25(OH)D2-D6 and 25(OH)D3-D3 as internal standard, application of 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD) as derivatization reagent. The procedure is carried out in a 96-well plate format in an automated liquid handling platform to facilitate high-throughput analysis. The processed sample is separated in a C18 column with water-methanol gradient elution, and quantitated by mass spectrometry in multiple reaction monitoring (MRM) mode. For both 25(OH)D2 and 25(OH)D3, the linear range of quantitation is 0.94-120 ng/mL, the limit of detection is 0.12 ng/mL (S/N=3), and the limit of quantitation is 0.94 ng/mL (S/N=10). The intra-day relative standard deviation (RSD) values of 25(OH)D2 and 25(OH)D3 are 1.4%-6.6%, 3.7%-7.0%, respectively. The inter-day RSD values of 25(OH)D2 and 25(OH)D3 are 4.0%-5.3%, 3.8-10.6%, respectively. The recovery (mean±SD) in 5 consecutive of 25(OH)D2 is 98.7%±4.6%-108.5%±6.5%, and that of 25(OH)D3 is 94.8%±6.8%-101.3%±2.9%. DBS sample stability is confirmed by measuring identical DBS samples stored for 0, 1, 2, 3, 5, 7 and 14 days at -20℃, 22℃, and 37℃, and an overall RSD<15% was observed under each temperature. DBS sample stability in freeze-thaw cycles is also confirmed by experimenting identical DBS samples up to 14 free-thaw cycles (each cycle consisting of 23 h freezing at -80℃ followed by 1 h thaw at room temperature), and an overall RSD<15% is observed. The accuracy of 25(OH)D2 and 25(OH)D3 quantitation is validated by measuring a DBS sample prepared from NIST reference material SRM972a Level 3 and the recovery is found to be 110.3% and 103.0%.
2017, 45(3): 455-463
doi: 10.11895/j.issn.0253-3820.160623
Abstract:
Wearable microfluidics have wide applications in medical, sports and military field. With the help of wearable microfluidics, through the direct physical contact between the chip and skin, the pH, glucose, lactate, sodium/potassium, calcium and heavy metal in the body fluid can be detected from sweat, tear and saliva without puncture for blood. And these information are of great importance for the monitoring of vital signs and disease diagnosis. This paper introduced the most recent development and applications of the wearable microfluidics in the body fluid testing and drug delivery. The up-to-date research development for the drug delivery using wearable microfluidics was also briefly introduced in this article. The forecast of the emerging trend for wearable microfluidics and discussion of potential technique barriers was also provided at the end of this article.
Wearable microfluidics have wide applications in medical, sports and military field. With the help of wearable microfluidics, through the direct physical contact between the chip and skin, the pH, glucose, lactate, sodium/potassium, calcium and heavy metal in the body fluid can be detected from sweat, tear and saliva without puncture for blood. And these information are of great importance for the monitoring of vital signs and disease diagnosis. This paper introduced the most recent development and applications of the wearable microfluidics in the body fluid testing and drug delivery. The up-to-date research development for the drug delivery using wearable microfluidics was also briefly introduced in this article. The forecast of the emerging trend for wearable microfluidics and discussion of potential technique barriers was also provided at the end of this article.
