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2016 Volume 44 Issue 7
2016, 44(7): 1003-1008
doi: 10.11895/j.issn.0253-3820.160089
Abstract:
Chlorofluorocarbons (CFCs) and sulfur hexafluoride (SF6) are kinds of anthropogenic halogenated compounds. They are very important for the ocean processes including air-sea exchange, water mass exchange etc. Meanwhile, they can be used to calculate some key physical and biogeochemical parameters such as AOUR (apparent oxygen utilization rate) and Cant (anthropogenic CO2). In comparison with CFCs, it is quite difficult to measure SF6 in the seawater due to its low solubility. However, it is useful to study the oceanic processes based on both the CFCs and SF6. In this study, a purge and trap gas chromatographic system was developed to measure the CFC-12 and SF6 simultaneously in seawater. The optimum conditions were as follows:trap temperature of -70℃, purge time of 8 min, purge gas pressure of 310 kPa, desorption time of 30 s, and desorption temperature of 90℃. The detection limit of CFC-12 and SF6 were 0.02 pmol/kg and 0.03 fmol/kg, respectively. The analytical precisions of CFC-12 and SF6 were ±1.2% and ±0.5%, respectively. The correlation coefficients (R2) of all the calibration curves were greater than 0.9995. This method was successfully used in the analysis of the samples collected from 6th Chinese Arctic Research Expedition.
Chlorofluorocarbons (CFCs) and sulfur hexafluoride (SF6) are kinds of anthropogenic halogenated compounds. They are very important for the ocean processes including air-sea exchange, water mass exchange etc. Meanwhile, they can be used to calculate some key physical and biogeochemical parameters such as AOUR (apparent oxygen utilization rate) and Cant (anthropogenic CO2). In comparison with CFCs, it is quite difficult to measure SF6 in the seawater due to its low solubility. However, it is useful to study the oceanic processes based on both the CFCs and SF6. In this study, a purge and trap gas chromatographic system was developed to measure the CFC-12 and SF6 simultaneously in seawater. The optimum conditions were as follows:trap temperature of -70℃, purge time of 8 min, purge gas pressure of 310 kPa, desorption time of 30 s, and desorption temperature of 90℃. The detection limit of CFC-12 and SF6 were 0.02 pmol/kg and 0.03 fmol/kg, respectively. The analytical precisions of CFC-12 and SF6 were ±1.2% and ±0.5%, respectively. The correlation coefficients (R2) of all the calibration curves were greater than 0.9995. This method was successfully used in the analysis of the samples collected from 6th Chinese Arctic Research Expedition.
2016, 44(7): 1009-1014
doi: 10.11895/j.issn.0253-3820.150960
Abstract:
A gas chromatographic (GC) method was established for the simultaneous analysis of seven short-chain fatty acids (SCFAs) including acetic acid, propionic acid, isobutyric acid, butyric acid, isovaleric acid, valeric acid and hexanoic acid in human saliva. Salivary sample was diluted by ethanol solution by ratio of 1:1 (V/V), with 0.5% (V/V) hydrochloric acid in sample solution, then vortexed and centrifuged. The supernatent was subjected to GC analysis. The chromatographic separation was performed on a DB-FFAP capillary column (30 m×0.25 mm×0.25 μm) using flame ionization detector (FID). The quantification was achieved by internal standard method. The experimental results showed that an excellent correlation coefficient (R2≥0.999) was obtained for all the calibration curves of seven SCFAs. The limits of detection (LOD, S/N=3) and limits of quantitation (LOQ, S/N=10) were 0.060-0.198 μg/mL and 0.180-0.594 μg/mL, respectively. The average recoveries were 94.8%-109.7% with relative standard deviation (RSD)≤4.3% (n=6). The developed method is simple, rapid and accurate, and suitable for the simultaneous determination of seven SCFAs in human saliva.
A gas chromatographic (GC) method was established for the simultaneous analysis of seven short-chain fatty acids (SCFAs) including acetic acid, propionic acid, isobutyric acid, butyric acid, isovaleric acid, valeric acid and hexanoic acid in human saliva. Salivary sample was diluted by ethanol solution by ratio of 1:1 (V/V), with 0.5% (V/V) hydrochloric acid in sample solution, then vortexed and centrifuged. The supernatent was subjected to GC analysis. The chromatographic separation was performed on a DB-FFAP capillary column (30 m×0.25 mm×0.25 μm) using flame ionization detector (FID). The quantification was achieved by internal standard method. The experimental results showed that an excellent correlation coefficient (R2≥0.999) was obtained for all the calibration curves of seven SCFAs. The limits of detection (LOD, S/N=3) and limits of quantitation (LOQ, S/N=10) were 0.060-0.198 μg/mL and 0.180-0.594 μg/mL, respectively. The average recoveries were 94.8%-109.7% with relative standard deviation (RSD)≤4.3% (n=6). The developed method is simple, rapid and accurate, and suitable for the simultaneous determination of seven SCFAs in human saliva.
2016, 44(7): 1015-1021
doi: 10.11895/j.issn.0253-3820.160023
Abstract:
A novel electrochemical immunosensor was developed for detection of E. coli in urban sludge based on dendrimer-encapsulated Au and enhanced gold nanoparticle labels. p-Aminobenzoic acid (p-ABA) was electropolymerized on glassy carbon electrode (GCE) surface to introduce abundant carboxyl groups. G4-polyamidoamine dendrimers (PAMAM) were covalently attached onto electrode surface through the formation of amide bonds between amino groups of dendrimer and carboxyl groups of poly-p-ABA. Subsequently, Au(Ⅲ) ions were coordinated in the interior of dendrimer and then reduced to form gold nanoparticles (AuNPs). The resulting electrode (GCE/p-ABA/PAMAM(AuNPs)) provided numerous amino groups to allow highly dense immobilization of E. coli, and facilitated the improvement of electrochemical responses. The rabbit anti-E. coli polyclonal antibody (Ab1) was captured by the electrode surface-confined E. coli, followed by the attachment of the enhanced gold nanoparticle labels (Ab2-Au-Th) featuring thionine (Th) as signal-generating molecule. The analysis of E. coli was performed by electrochemical detection of Th in the bound labels on the electrode surface. Under the optimal experimental conditions, a linear relationship between the peak current of Th and the logarithmic value of E. coli concentration ranging from 1.0×102 cfu/mL to 1.0×106 cfu/mL was obtained with a detection limit of 70 cfu/mL (S/N=3). The proposed strategy was also used to determine E. coli in samples obtained from waste water treatment plant, and the recoveries of standard additions were in the range of 89.4% to 105.8%. The results confirmed that the electrochemical immunoassay gave a useful protocol for E. coli analysis with high sensitivity, specificity and acceptable accuracy, and thus could potentially become a promising technique for estimating the feasibility of sludge recycling.
A novel electrochemical immunosensor was developed for detection of E. coli in urban sludge based on dendrimer-encapsulated Au and enhanced gold nanoparticle labels. p-Aminobenzoic acid (p-ABA) was electropolymerized on glassy carbon electrode (GCE) surface to introduce abundant carboxyl groups. G4-polyamidoamine dendrimers (PAMAM) were covalently attached onto electrode surface through the formation of amide bonds between amino groups of dendrimer and carboxyl groups of poly-p-ABA. Subsequently, Au(Ⅲ) ions were coordinated in the interior of dendrimer and then reduced to form gold nanoparticles (AuNPs). The resulting electrode (GCE/p-ABA/PAMAM(AuNPs)) provided numerous amino groups to allow highly dense immobilization of E. coli, and facilitated the improvement of electrochemical responses. The rabbit anti-E. coli polyclonal antibody (Ab1) was captured by the electrode surface-confined E. coli, followed by the attachment of the enhanced gold nanoparticle labels (Ab2-Au-Th) featuring thionine (Th) as signal-generating molecule. The analysis of E. coli was performed by electrochemical detection of Th in the bound labels on the electrode surface. Under the optimal experimental conditions, a linear relationship between the peak current of Th and the logarithmic value of E. coli concentration ranging from 1.0×102 cfu/mL to 1.0×106 cfu/mL was obtained with a detection limit of 70 cfu/mL (S/N=3). The proposed strategy was also used to determine E. coli in samples obtained from waste water treatment plant, and the recoveries of standard additions were in the range of 89.4% to 105.8%. The results confirmed that the electrochemical immunoassay gave a useful protocol for E. coli analysis with high sensitivity, specificity and acceptable accuracy, and thus could potentially become a promising technique for estimating the feasibility of sludge recycling.
2016, 44(7): 1022-1028
doi: 10.11895/j.issn.0253-3820.150615
Abstract:
A novel labeling approach with good compatibility based on 2-(4-isothiocyanatobenzyl)-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (p-SCN-Bn-DOTA) was established. The labeling conditions of p-SCN-Bn-DOTA with standard peptides were optimized, and the labeling efficiency of macrocyclic complex of p-SCN-Bn-DOTA with lanthanide metal ion Eu(Ⅲ) was also investigated. The labeling process was a two-step reaction. The labeling efficiency was affected by several factors including pH, buffer, reaction time, reaction temperature, and ratio of p-SCN-Bn-DOTA to peptide. The optimized conditions were as followed:the first step of labeling reaction was reacted in 0.2 mol/L triethylene diamine (TEAB) (pH 8.5) buffer for 60 min at 60℃, and the molar ratio of p-SCN-Bn-DOTA with peptide was 32. The second step of rare earth metal chelating was in pH 4.0 HCl/NaAC buffer for 60 min at 60℃. This approach was successfully applied in RGD peptide labeling.
A novel labeling approach with good compatibility based on 2-(4-isothiocyanatobenzyl)-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (p-SCN-Bn-DOTA) was established. The labeling conditions of p-SCN-Bn-DOTA with standard peptides were optimized, and the labeling efficiency of macrocyclic complex of p-SCN-Bn-DOTA with lanthanide metal ion Eu(Ⅲ) was also investigated. The labeling process was a two-step reaction. The labeling efficiency was affected by several factors including pH, buffer, reaction time, reaction temperature, and ratio of p-SCN-Bn-DOTA to peptide. The optimized conditions were as followed:the first step of labeling reaction was reacted in 0.2 mol/L triethylene diamine (TEAB) (pH 8.5) buffer for 60 min at 60℃, and the molar ratio of p-SCN-Bn-DOTA with peptide was 32. The second step of rare earth metal chelating was in pH 4.0 HCl/NaAC buffer for 60 min at 60℃. This approach was successfully applied in RGD peptide labeling.
2016, 44(7): 1029-1034
doi: 10.11895/j.issn.0253-3820.160040
Abstract:
To search an optimum spectral pretreatment method to measure Pb content in the leg muscle of pork with laser-induced breakdown spectroscopy, a total of 84 pork samples were split into calibration and prediction sets. With correlation coefficient (R), root-mean-square error of cross-validation (RMSECV) and root-mean-square error of predictionas (RMSEP) as the evaluation index, the effect of five pretreatment methods to the model based on partial least square (PLS) were compared. The results showed that the multiplicative scatter correction (MSC) was most effective and its R, RMSECV, RMSEP and principal element were 0.9908, 0.302, 0.282 and 16, respectively. The average relative error of prediction sets of 18 samples was 7.8%. The MSC is an efficient method to measure Pb in pork with laser-induced breakdown spectroscopy. The research provides an approach for further improving the accuracy of LIBS quantitative analysis of heavy metals in food.
To search an optimum spectral pretreatment method to measure Pb content in the leg muscle of pork with laser-induced breakdown spectroscopy, a total of 84 pork samples were split into calibration and prediction sets. With correlation coefficient (R), root-mean-square error of cross-validation (RMSECV) and root-mean-square error of predictionas (RMSEP) as the evaluation index, the effect of five pretreatment methods to the model based on partial least square (PLS) were compared. The results showed that the multiplicative scatter correction (MSC) was most effective and its R, RMSECV, RMSEP and principal element were 0.9908, 0.302, 0.282 and 16, respectively. The average relative error of prediction sets of 18 samples was 7.8%. The MSC is an efficient method to measure Pb in pork with laser-induced breakdown spectroscopy. The research provides an approach for further improving the accuracy of LIBS quantitative analysis of heavy metals in food.
2016, 44(7): 1035-1041
doi: 10.11895/j.issn.0253-3820.151006
Abstract:
Limits of detection (LODs), ICP mass load effect, downhole induced fractionation and matrix effect of 193 nm ArF excimer laser ablation system at high spatial resolution were systematically investigated. Trace elements in GSD-1G, StHs6/80-G and NIST612 were analyzed at 10 μm spot size. The results showed that LODs decreased with increasing ablation diameter. LODs of some trace elements were in a range of 1-10μg/g at 7 μm spot size. Mass load effect was negatively correlated with corresponding oxide melting temperature, while positively correlated with elemental 1st ionization potential. Downhole fractionation was negligible when the ratio of ablation depth versus spot size was smaller than 1:1. Matrix effect based on elemental pair method showed that there was no significant change between spot sizes of 50 μm and 10 μm among investigated reference materials (NIST610, GSD-1G, ATHO-G and StHs6/80-G). Based on NIST610 as external standard and Ca as internal standard, the analytical results of 36 trace elements in GSD-1G, StHs6/80-G and NIST612 at 10μm spot size matched well with the reference value. In general, 10 μm spatial resolution could satisfy the requirements of trace element analysis.
Limits of detection (LODs), ICP mass load effect, downhole induced fractionation and matrix effect of 193 nm ArF excimer laser ablation system at high spatial resolution were systematically investigated. Trace elements in GSD-1G, StHs6/80-G and NIST612 were analyzed at 10 μm spot size. The results showed that LODs decreased with increasing ablation diameter. LODs of some trace elements were in a range of 1-10μg/g at 7 μm spot size. Mass load effect was negatively correlated with corresponding oxide melting temperature, while positively correlated with elemental 1st ionization potential. Downhole fractionation was negligible when the ratio of ablation depth versus spot size was smaller than 1:1. Matrix effect based on elemental pair method showed that there was no significant change between spot sizes of 50 μm and 10 μm among investigated reference materials (NIST610, GSD-1G, ATHO-G and StHs6/80-G). Based on NIST610 as external standard and Ca as internal standard, the analytical results of 36 trace elements in GSD-1G, StHs6/80-G and NIST612 at 10μm spot size matched well with the reference value. In general, 10 μm spatial resolution could satisfy the requirements of trace element analysis.
2016, 44(7): 1042-1046
doi: 10.11895/j.issn.0253-3820.160134
Abstract:
In the preparation of active luminescent glass, trace elements are generally co-doped to improve the properties. To overcome the poor sensitivity of laser-induced breakdown spectroscopy (LIBS) on detecting trace elements in glass, this work utilized laser-induced breakdown spectroscopy combined with laser-induced fluorescence to detect trace Yb, Al and P. A wavelength-tunable laser was used to excited Yb ions, Al atoms and P atoms. The transition process in laser-induced fluorescence was described. The results showed that the spectral intensities of Yb, Al and P were enhanced by 23, 50 and 8 times, respectively. LIBS sensitivity was greatly improved by combining laser-induced fluorescence.
In the preparation of active luminescent glass, trace elements are generally co-doped to improve the properties. To overcome the poor sensitivity of laser-induced breakdown spectroscopy (LIBS) on detecting trace elements in glass, this work utilized laser-induced breakdown spectroscopy combined with laser-induced fluorescence to detect trace Yb, Al and P. A wavelength-tunable laser was used to excited Yb ions, Al atoms and P atoms. The transition process in laser-induced fluorescence was described. The results showed that the spectral intensities of Yb, Al and P were enhanced by 23, 50 and 8 times, respectively. LIBS sensitivity was greatly improved by combining laser-induced fluorescence.
2016, 44(7): 1047-1052
doi: 10.11895/j.issn.0253-3820.150818
Abstract:
A green, simple and convenient method for determination of cadmium and lead in PM2.5 by slurry sampling graphite furnace atomic absorption spectrometry was established. PM2.5 samples were collected from Changning district in Shanghai using quartz microfiber filters membranes and grinded into μm-size fine particles by grinding mill for 4 min. The 0.7% Triton X-100 was used as dispersing agent and the pH value was adjusted to 2 by 1% HNO3. The detection limit of cadmium and lead was 0.36 and 0.06 μg/L, respectively, and the linear correlation coefficient of the calibration curves of cadmium in the range of 0.2-3 μg/L and lead in the range of 0.1-75 μg/L was better than 0.998, with a relative standard deviation being not more than 5.0%. The accuracy of the proposed method was verified by comparing the determination result with that by graphite furnace atomic absorption spectrometry and inductively coupled plasma mass spectrometry using solution of acid digestion. The pollution characteristics of cadmium and lead in PM2.5 were analyzed and the result showed that the trend of the mass concentration of PM2.5 with time was consistent with the trends of cadmium and lead.
A green, simple and convenient method for determination of cadmium and lead in PM2.5 by slurry sampling graphite furnace atomic absorption spectrometry was established. PM2.5 samples were collected from Changning district in Shanghai using quartz microfiber filters membranes and grinded into μm-size fine particles by grinding mill for 4 min. The 0.7% Triton X-100 was used as dispersing agent and the pH value was adjusted to 2 by 1% HNO3. The detection limit of cadmium and lead was 0.36 and 0.06 μg/L, respectively, and the linear correlation coefficient of the calibration curves of cadmium in the range of 0.2-3 μg/L and lead in the range of 0.1-75 μg/L was better than 0.998, with a relative standard deviation being not more than 5.0%. The accuracy of the proposed method was verified by comparing the determination result with that by graphite furnace atomic absorption spectrometry and inductively coupled plasma mass spectrometry using solution of acid digestion. The pollution characteristics of cadmium and lead in PM2.5 were analyzed and the result showed that the trend of the mass concentration of PM2.5 with time was consistent with the trends of cadmium and lead.
2016, 44(7): 1053-1058
doi: 10.11895/j.issn.0253-3820.160164
Abstract:
The isotopic abundance of lead as a signature or fingerprint in uranium has played an important role in nuclear forensics analysis. In this work, a novel analytical approach is presented to determine the isotopic abundance of lead in uranium particles by laser ablation multiple collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS). External standardization method is involved in correcting the mass fractionation in the process of analysis. The approach has been successfully validated by the measurement of CRM124-4 standard reference material. Spot size and ablation rate are set at 30 μm and 20 Hz, respectively. Laser energy density is under control to ensure that the 208Pb for NIST SRM612 and uranium particles are less than 1.5×105 cps and 3×104 cps, respectively. The results show that the relative uncertainty of 206Pb/208Pb, 206Pb/207Pb and 207Pb/208Pb ratios in CRM124-4 are less than 0.48%, 0.68% and 0.40%, respectively. Two kinds of uranium particles originated from different places have been analyzed by the proposed approach. The results demonstrate that the distinct lead isotope signatures can offer a number of evidence to determine whether the uranium particles have come directly from a mining operation or an ore-body, or whether it is anthropogenic.
The isotopic abundance of lead as a signature or fingerprint in uranium has played an important role in nuclear forensics analysis. In this work, a novel analytical approach is presented to determine the isotopic abundance of lead in uranium particles by laser ablation multiple collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS). External standardization method is involved in correcting the mass fractionation in the process of analysis. The approach has been successfully validated by the measurement of CRM124-4 standard reference material. Spot size and ablation rate are set at 30 μm and 20 Hz, respectively. Laser energy density is under control to ensure that the 208Pb for NIST SRM612 and uranium particles are less than 1.5×105 cps and 3×104 cps, respectively. The results show that the relative uncertainty of 206Pb/208Pb, 206Pb/207Pb and 207Pb/208Pb ratios in CRM124-4 are less than 0.48%, 0.68% and 0.40%, respectively. Two kinds of uranium particles originated from different places have been analyzed by the proposed approach. The results demonstrate that the distinct lead isotope signatures can offer a number of evidence to determine whether the uranium particles have come directly from a mining operation or an ore-body, or whether it is anthropogenic.
2016, 44(7): 1059-1064
doi: 10.11895/j.issn.0253-3820.160033
Abstract:
A fast testing method was established for the determination of zaleplon and its two metabolites, 5-oxozaleplon and desethylzaleplon, in blood by ultra performance liquid chromatography tandem electrospray ionization triple quadrapole-mass spectrometry (UPLC-TQ/MS). The optimized QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method was used for sample preparation. The blood samples were extracted with 0.1% acetic acid and dehydrated by adding anhydrous magnesium sulfate. The targets were separated on a Waters BEH C18 column by gradient elution with 0.1% formic acid-0.1% formic acid/acetonitrile as mobile phase, ionized with positive electrospray (ESI+), and detected under multiple reaction monitoring (MRM) mode. As a result, zaleplon and its two metabolites displayed excellent linearity in the concentration of 0.5-100 ng/mL (R2>0.997). The average recoveries ranged from 92.0% to 100.1%. The RSD were in the range of 1.9%-5.3%. Besides, the limit of detection(LOD)of this method for target drugs was 0.05 ng/mL (S/N=3), while limits of quantification (LOQ) were in the range of 0.1-0.5 ng/mL (S/N=10). This method can meet the demand of rapidity and accuracy in the analysis of actual cases.
A fast testing method was established for the determination of zaleplon and its two metabolites, 5-oxozaleplon and desethylzaleplon, in blood by ultra performance liquid chromatography tandem electrospray ionization triple quadrapole-mass spectrometry (UPLC-TQ/MS). The optimized QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method was used for sample preparation. The blood samples were extracted with 0.1% acetic acid and dehydrated by adding anhydrous magnesium sulfate. The targets were separated on a Waters BEH C18 column by gradient elution with 0.1% formic acid-0.1% formic acid/acetonitrile as mobile phase, ionized with positive electrospray (ESI+), and detected under multiple reaction monitoring (MRM) mode. As a result, zaleplon and its two metabolites displayed excellent linearity in the concentration of 0.5-100 ng/mL (R2>0.997). The average recoveries ranged from 92.0% to 100.1%. The RSD were in the range of 1.9%-5.3%. Besides, the limit of detection(LOD)of this method for target drugs was 0.05 ng/mL (S/N=3), while limits of quantification (LOQ) were in the range of 0.1-0.5 ng/mL (S/N=10). This method can meet the demand of rapidity and accuracy in the analysis of actual cases.
2016, 44(7): 1065-1070
doi: 10.11895/j.issn.0253-3820.151021
Abstract:
A new method was developed for the determination of mercapto compounds by pre-column derivatization combined with acid-induced transient isotachophoretic stacking capillary electrophoresis. Mercapto compounds were derivatized with 2-chloro-1-methylpyridinium iodide (CMPI) in Tris-HCl buffer solution at pH 8.15 at room temperature. The derivatized mercapto compounds were introduced into the capillary filled up with 40 mmol/L formate buffer (pH=3.96), followed by injection of diluted sulfuric acid. Upon application of voltage at normal polarity, the derivatized mercapto compounds were preconcentrated due to transient isotachophoresis stacking electrophoresis with H+ as the leading ion and Tris+ as the terminating ion. The detection wavelength was set at 312 nm. Cysteine and sodium thioglycolate were chosen as the models of mercapto compounds to be detected. Various experimental factors influencing transient isotachophoresis stacking were investigated. Under the optimal conditions, the linear relation between peak area and concentration was obtained in the range from 10 mg/L to 100 mg/L for cysteine, and from 4 mg/L to 100 mg/L for sodium thioglycolate. The LODs were 0.2 mg/L and 0.4 mg/L for cysteine and sodium thioglycolate, respectively. The developed method was successfully applied to the determination of thioglycolate in depilatory cream samples.
A new method was developed for the determination of mercapto compounds by pre-column derivatization combined with acid-induced transient isotachophoretic stacking capillary electrophoresis. Mercapto compounds were derivatized with 2-chloro-1-methylpyridinium iodide (CMPI) in Tris-HCl buffer solution at pH 8.15 at room temperature. The derivatized mercapto compounds were introduced into the capillary filled up with 40 mmol/L formate buffer (pH=3.96), followed by injection of diluted sulfuric acid. Upon application of voltage at normal polarity, the derivatized mercapto compounds were preconcentrated due to transient isotachophoresis stacking electrophoresis with H+ as the leading ion and Tris+ as the terminating ion. The detection wavelength was set at 312 nm. Cysteine and sodium thioglycolate were chosen as the models of mercapto compounds to be detected. Various experimental factors influencing transient isotachophoresis stacking were investigated. Under the optimal conditions, the linear relation between peak area and concentration was obtained in the range from 10 mg/L to 100 mg/L for cysteine, and from 4 mg/L to 100 mg/L for sodium thioglycolate. The LODs were 0.2 mg/L and 0.4 mg/L for cysteine and sodium thioglycolate, respectively. The developed method was successfully applied to the determination of thioglycolate in depilatory cream samples.
2016, 44(7): 1071-1076
doi: 10.11895/j.issn.0253-3820.160078
Abstract:
Flavonoids are reported to have a variety of biological activities. Investigations on the interactions of flavonoids with protein are essential to understand the biological activities of flavnoids. In this paper, by using the optimized matrix 2,5-dihydroxybenzoic acid (DHB), we investigated the interaction of five flavonoids (luteolin, apigenin, genisten, quercetin, dazein) with lyszoyme using intensity fading (IF)-MALDI-MS method. The changes of relative abundances of flavonoids before and after addition of lyszoyme were calculated, and the binding affinity order was obtained by competitive experiments. It was found that all of the five flavonoids bound specifically to lysozyme. And the order of binding affinities of the five flavonoids to the lysozyme was luteolin>apigenin, genisten > quercetin > dazein. Based on their structures, it was found that the hydroxyl on C5 and C3' benefited the binding of flavonoid towards lyszoyme. However, the hydroxyl on C3 hindered the binding of flavonoid towards lysozyme. The results should be helpful to understand the biological activity of flavonoids. And the IF-MALDI-MS method could also be used to screening the interactions of other natural products and protein.
Flavonoids are reported to have a variety of biological activities. Investigations on the interactions of flavonoids with protein are essential to understand the biological activities of flavnoids. In this paper, by using the optimized matrix 2,5-dihydroxybenzoic acid (DHB), we investigated the interaction of five flavonoids (luteolin, apigenin, genisten, quercetin, dazein) with lyszoyme using intensity fading (IF)-MALDI-MS method. The changes of relative abundances of flavonoids before and after addition of lyszoyme were calculated, and the binding affinity order was obtained by competitive experiments. It was found that all of the five flavonoids bound specifically to lysozyme. And the order of binding affinities of the five flavonoids to the lysozyme was luteolin>apigenin, genisten > quercetin > dazein. Based on their structures, it was found that the hydroxyl on C5 and C3' benefited the binding of flavonoid towards lyszoyme. However, the hydroxyl on C3 hindered the binding of flavonoid towards lysozyme. The results should be helpful to understand the biological activity of flavonoids. And the IF-MALDI-MS method could also be used to screening the interactions of other natural products and protein.
2016, 44(7): 1077-1084
doi: 10.11895/j.issn.0253-3820.160112
Abstract:
A carbon ceramic electrode (CCE) was modified with a composite film composed of gold nanoparticles (AuNPs), overoxidized polypyrrole (OPPy), and multi-walled carbon nanotubes (MWCNTs) by two-step procedure. Firstly, MWCNTs were modified on the CCE surface by dropping method. Then, OPPy and gold nanoparticels were electrochemically deposited on the surface of MWCNTs layer by layer. The surface morphology and electrochemical properties of this modified electrode was studied. Furthermore, the electrochemical behaviors of hydroquinone (HQ) and catechol (CC) were also investigated in 0.10 mol/L phosphate buffer solution (PBS) (pH 7.0) using this modified electrode. The results showed that the modified electrode had high electrochemical activity and good selectivity for the oxidation of HQ and CC. Under the optimal conditions, the linear range for the simultaneous determination of HQ and CC by first derivative voltammetry was from 2.0×10-7 to 1.0×10-4 mol/L, respectively. The detection limit for HQ and CC was 6.0×10-8 and 8.0×10-8 mol/L (S/N=3), respectively. The recoveries of HQ and CC in simulated water samples were 96.2%-99.8% and 96.0%-100.0%, resptively, which indicated the good practicability of the method.
A carbon ceramic electrode (CCE) was modified with a composite film composed of gold nanoparticles (AuNPs), overoxidized polypyrrole (OPPy), and multi-walled carbon nanotubes (MWCNTs) by two-step procedure. Firstly, MWCNTs were modified on the CCE surface by dropping method. Then, OPPy and gold nanoparticels were electrochemically deposited on the surface of MWCNTs layer by layer. The surface morphology and electrochemical properties of this modified electrode was studied. Furthermore, the electrochemical behaviors of hydroquinone (HQ) and catechol (CC) were also investigated in 0.10 mol/L phosphate buffer solution (PBS) (pH 7.0) using this modified electrode. The results showed that the modified electrode had high electrochemical activity and good selectivity for the oxidation of HQ and CC. Under the optimal conditions, the linear range for the simultaneous determination of HQ and CC by first derivative voltammetry was from 2.0×10-7 to 1.0×10-4 mol/L, respectively. The detection limit for HQ and CC was 6.0×10-8 and 8.0×10-8 mol/L (S/N=3), respectively. The recoveries of HQ and CC in simulated water samples were 96.2%-99.8% and 96.0%-100.0%, resptively, which indicated the good practicability of the method.
2016, 44(7): 1085-1091
doi: 10.11895/j.issn.0253-3820.150902
Abstract:
A phage clone (designated as the anti-aflatoxin B1 nanobody, G8) specific binding to aflatoxin B1 (AFB1) was screened from an immunized nanobody phage library. The DNA fragment encoding G8 was subcloned into the vector pET25b(+)-alkaline phosphatase (AP), and fused to the N terminal of AP. The fusion protein G8-AP was expressed in E. coli BL21 (Rosetta, DE3) as soluble protein, and purified by immobilized metal affinity chromatography. The purified G8-AP exhibited AP activity of 364.5±8.3 U/mg. Enzyme-linked immunosorbent assay (ELISA) showed that G8-AP was also capable of recognizing AFB1, with negligible cross-reactivity toward other six common mycotoxins. A one-step ELISA was established to detect AFB1 using G8-AP. The effects of methanol concentration, ionic strength, and pH on the detection sensitivity of the G8-AP-ELISA were evaluated and optimized. Under the optimized conditions (methanol 20%, NaCl 20 mmol/L, pH 7.4), the half inhibitory concentration (IC50) of the G8-AP based ELISA was 19.8 ng/mL, with the linear range of 4.3-92 ng/mL and the detection limit of 2.6 ng/mL. The recoveries of AFB1 for corn and wheat samples were 90.4%-101.5%.
A phage clone (designated as the anti-aflatoxin B1 nanobody, G8) specific binding to aflatoxin B1 (AFB1) was screened from an immunized nanobody phage library. The DNA fragment encoding G8 was subcloned into the vector pET25b(+)-alkaline phosphatase (AP), and fused to the N terminal of AP. The fusion protein G8-AP was expressed in E. coli BL21 (Rosetta, DE3) as soluble protein, and purified by immobilized metal affinity chromatography. The purified G8-AP exhibited AP activity of 364.5±8.3 U/mg. Enzyme-linked immunosorbent assay (ELISA) showed that G8-AP was also capable of recognizing AFB1, with negligible cross-reactivity toward other six common mycotoxins. A one-step ELISA was established to detect AFB1 using G8-AP. The effects of methanol concentration, ionic strength, and pH on the detection sensitivity of the G8-AP-ELISA were evaluated and optimized. Under the optimized conditions (methanol 20%, NaCl 20 mmol/L, pH 7.4), the half inhibitory concentration (IC50) of the G8-AP based ELISA was 19.8 ng/mL, with the linear range of 4.3-92 ng/mL and the detection limit of 2.6 ng/mL. The recoveries of AFB1 for corn and wheat samples were 90.4%-101.5%.
2016, 44(7): 1092-1098
doi: 10.11895/j.issn.0253-3820.160010
Abstract:
A sensitive method for Pb2+ detection based on a cationic conjugated polymer and aptamer was established. By selecting a more specific aptamer probe, the interference of Pb2+ detection from Hg2+ was eliminated remarkably. The probe for Pb2+ recognition and combination is a single stranded oligonucleotide labeled with fluorescein (TBAA, 5'-6-FAM-GGAAGGTGTGGAAGG-3'). When combining with Pb2+ with high specificity, the random coiled probe changed to a G-quadruplex with higher charge density, which enhanced the electrostatic interactions between the oligonucleotide and cationic conjugated polymer, thus the two fluorophores were in more close proximity, leading to a significantly increased fluorescence resonance energy transfer (FRET) signal. However, other non-target metal ions produced much lower FRET signals because they could not combine with the probe and thus quenched the fluorescence of the conjugated polymer and fluorescein. This method was rapid, highly specific and sensitive, and the common metal ions including Li+, Na+, K+, Ca2+, Mg2+, Ba2+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+ and Hg2+ exhibited no influence on the detection of Pb2+. The limit of detection for Pb2+ in lake water was estimated to be 1 nmol/L (3σ), which was far below the maximum permitted level of Pb2+ in drink water regulated by the national standard for drinking water quality. Therefore, this FRET-based method provides a new simple, rapid, and efficient method for detection of Pb2+ in various source of water.
A sensitive method for Pb2+ detection based on a cationic conjugated polymer and aptamer was established. By selecting a more specific aptamer probe, the interference of Pb2+ detection from Hg2+ was eliminated remarkably. The probe for Pb2+ recognition and combination is a single stranded oligonucleotide labeled with fluorescein (TBAA, 5'-6-FAM-GGAAGGTGTGGAAGG-3'). When combining with Pb2+ with high specificity, the random coiled probe changed to a G-quadruplex with higher charge density, which enhanced the electrostatic interactions between the oligonucleotide and cationic conjugated polymer, thus the two fluorophores were in more close proximity, leading to a significantly increased fluorescence resonance energy transfer (FRET) signal. However, other non-target metal ions produced much lower FRET signals because they could not combine with the probe and thus quenched the fluorescence of the conjugated polymer and fluorescein. This method was rapid, highly specific and sensitive, and the common metal ions including Li+, Na+, K+, Ca2+, Mg2+, Ba2+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+ and Hg2+ exhibited no influence on the detection of Pb2+. The limit of detection for Pb2+ in lake water was estimated to be 1 nmol/L (3σ), which was far below the maximum permitted level of Pb2+ in drink water regulated by the national standard for drinking water quality. Therefore, this FRET-based method provides a new simple, rapid, and efficient method for detection of Pb2+ in various source of water.
2016, 44(7): 1099-1105
doi: 10.11895/j.issn.0253-3820.160029
Abstract:
A novel fluorescence analysis method for fast detection of mercury ions in human urine was established based on DNA recognition and exonuclease I (Exo Ⅰ) assisted signal conversion strategy. The DNA immobilized on the surfaces of the microplates bound specifically with Hg2+ to fold into a stable "hairpin" double-stranded structure, thus avoided the hydrolysis by single-stranded DNA specific Exo Ⅰ. Nucleic acid dye SYBR Green I (SG) could insert into the double-stranded "hairpin" part to produce fluorescence signal emission. Based on the above facts, quantitative detection of mercury ions was achieved. The experimental results showed that, when the concentration of avidin coating solution was 50 mg/L and the concentration of the detection DNA immobilized on the microplate was 75 nmol/L, with 5×SG and 1.2 μL of Exo Ⅰ, the optimal analytical performance could be achieved. A good linear relationship between the fluorescence intensity of the system at 520 nm versus the logarithm of mercury ions concentration in the range of 2-500 nmol/L was obtained under the optimal conditions, and the detection limit was 1.5 nmol/L (3σ). The recoveries of mercury in spiked human urine samples were 96.3%-100.5% with the relative standard derivations (RSDs) of 2.1%-4.6%. The method had good selectivity with simple operation, and could be used for the detection of total mercury content after oxidizing other forms of mercury in urine into mercury ions (Ⅱ) using HNO3-KMnO4 oxidation method.
A novel fluorescence analysis method for fast detection of mercury ions in human urine was established based on DNA recognition and exonuclease I (Exo Ⅰ) assisted signal conversion strategy. The DNA immobilized on the surfaces of the microplates bound specifically with Hg2+ to fold into a stable "hairpin" double-stranded structure, thus avoided the hydrolysis by single-stranded DNA specific Exo Ⅰ. Nucleic acid dye SYBR Green I (SG) could insert into the double-stranded "hairpin" part to produce fluorescence signal emission. Based on the above facts, quantitative detection of mercury ions was achieved. The experimental results showed that, when the concentration of avidin coating solution was 50 mg/L and the concentration of the detection DNA immobilized on the microplate was 75 nmol/L, with 5×SG and 1.2 μL of Exo Ⅰ, the optimal analytical performance could be achieved. A good linear relationship between the fluorescence intensity of the system at 520 nm versus the logarithm of mercury ions concentration in the range of 2-500 nmol/L was obtained under the optimal conditions, and the detection limit was 1.5 nmol/L (3σ). The recoveries of mercury in spiked human urine samples were 96.3%-100.5% with the relative standard derivations (RSDs) of 2.1%-4.6%. The method had good selectivity with simple operation, and could be used for the detection of total mercury content after oxidizing other forms of mercury in urine into mercury ions (Ⅱ) using HNO3-KMnO4 oxidation method.
2016, 44(7): 1106-1111
doi: 10.11895/j.issn.0253-3820.160064
Abstract:
A new ultrasonic-assisted nebulization extraction (UANE) method coupled with silica-supported ionic liquid-based matrix solid phase dispersion(S-SIL-based MSPD) and solid phase extraction(SPE) was established for the extraction of five triazine herbicides from root of Panax ginseng C.A.Mey. High performance liquid chromatography (HPLC) was used to determine these analytes. Experimental parameters, which affect the recoveries of the analytes, were studied and optimized. The sample powder (300 mg) was mixed with 150 mg of silica gel ([C6MIM] [PF6] 2.0 mmol/g). After MSPD for 5 min, the mixtures were extracted in water (pH 7, NaCl 1.0%) by UANE for 10 min, and then eluted by 5.0 mL of acetonitrile from the SPE column (C18, 300 mg). Under the optimized conditions, the LODs of these five triazine herbicides are in the ranges of 0.020-0.035 μg/g, the concentration range of linear relationship of analytes (r2≥0.9992) are in the ranges of 0.15-20.00 μg/g. The recoveries of these five triazine herbicides are in the ranges of 78.2%-95.2%, the RSDs are in the range of 3.5%-6.0%. The method shows a quick, efficient, high purifying effect and high extraction rate for the target analytes, and can be used to extract pesticide residues in traditional Chinese medicine.
A new ultrasonic-assisted nebulization extraction (UANE) method coupled with silica-supported ionic liquid-based matrix solid phase dispersion(S-SIL-based MSPD) and solid phase extraction(SPE) was established for the extraction of five triazine herbicides from root of Panax ginseng C.A.Mey. High performance liquid chromatography (HPLC) was used to determine these analytes. Experimental parameters, which affect the recoveries of the analytes, were studied and optimized. The sample powder (300 mg) was mixed with 150 mg of silica gel ([C6MIM] [PF6] 2.0 mmol/g). After MSPD for 5 min, the mixtures were extracted in water (pH 7, NaCl 1.0%) by UANE for 10 min, and then eluted by 5.0 mL of acetonitrile from the SPE column (C18, 300 mg). Under the optimized conditions, the LODs of these five triazine herbicides are in the ranges of 0.020-0.035 μg/g, the concentration range of linear relationship of analytes (r2≥0.9992) are in the ranges of 0.15-20.00 μg/g. The recoveries of these five triazine herbicides are in the ranges of 78.2%-95.2%, the RSDs are in the range of 3.5%-6.0%. The method shows a quick, efficient, high purifying effect and high extraction rate for the target analytes, and can be used to extract pesticide residues in traditional Chinese medicine.
2016, 44(7): 1112-1118
doi: 10.11895/j.issn.0253-3820.151022
Abstract:
A high performance liquid chromatography with diode array detection method (HPLC-DAD) was established for determination of 20 forbidden industrial dyes in capsule shells. The capsule shell samples were repeatedly extracted three times under ultrasonication with acetonitrile-methanol solution (1:2, V/V). The extract was separated on Agilent ZORBAX Eclipse Plus C18 column with gradient elution by using acetonitrile and 0.3% triethylamine, 0.2% phosphoric acid aqueous solution (pH 2.7) as eluant, and then monitored under the detection wavelength of 360, 420, 460, 570 and 630 nm. The results showed that the linearity of 20 forbidden industrial dyes ranged from 0.5 to 20 μg/ml with correlation coefficients of 0.9991-1.0000. The limit of detection of the instrument was 0.05 to 0.27 μg/mL. The recoveries of these dyes (spiked at levels of 1, 3, and 10 μg/g) ranged from 64.12% to 114.89%, while intra-day and inter-day relative standard deviations ranged from 0.4% to 9.9% and 0.9% to 9.9%, respectively. The Limit of quantification of the method was 0.16-2.33 μg/g. This method is sample, rapid and sensitive, and suitable for routine determination of the forbidden industrial dyes in capsule shells.
A high performance liquid chromatography with diode array detection method (HPLC-DAD) was established for determination of 20 forbidden industrial dyes in capsule shells. The capsule shell samples were repeatedly extracted three times under ultrasonication with acetonitrile-methanol solution (1:2, V/V). The extract was separated on Agilent ZORBAX Eclipse Plus C18 column with gradient elution by using acetonitrile and 0.3% triethylamine, 0.2% phosphoric acid aqueous solution (pH 2.7) as eluant, and then monitored under the detection wavelength of 360, 420, 460, 570 and 630 nm. The results showed that the linearity of 20 forbidden industrial dyes ranged from 0.5 to 20 μg/ml with correlation coefficients of 0.9991-1.0000. The limit of detection of the instrument was 0.05 to 0.27 μg/mL. The recoveries of these dyes (spiked at levels of 1, 3, and 10 μg/g) ranged from 64.12% to 114.89%, while intra-day and inter-day relative standard deviations ranged from 0.4% to 9.9% and 0.9% to 9.9%, respectively. The Limit of quantification of the method was 0.16-2.33 μg/g. This method is sample, rapid and sensitive, and suitable for routine determination of the forbidden industrial dyes in capsule shells.
2016, 44(7): 1119-1124
doi: 10.11895/j.issn.0253-3820.160125
Abstract:
A bis(5-methyltetrazolium)amine-bonded magnetic nanoparticle adsorbent was prepared by chemically modifying magnetic nanoparticles Fe3O4@SiO2 via four steps chemical reactions. The physical properties of the adsorbent were characterized by X-ray photoelectron spectroscopy (XPS) and Zeta potential. The static adsorption behavior of lysozyme, cytochrome C and chymotrypsin on the chelated Cu(Ⅱ) adsorbent, as well as the influences of the pH value of solution, ion strength and initial protein concentration on the adsorption capacity were evaluated with batch method. The results illustrated that the adsorption of protein proceeded via metal coordination mechanism and was also in accordance with Langmuir adsorption model, and the maximum adsorption capacities of lysozyme, cytochrome C and chymotrypsin were calculated to be 20.0 mg/g, 13.5 mg/g, and 17.9 mg/g, respectively. In addition, the chelated Cu(Ⅱ) adsorbent was employed to adsorb protein mixture, showing that this new type of adsorbent had selective adsorption to protein mixture. These results illustrated that the metal-chelated adsorbent had potential application value in selectively separating and enriching proteins.
A bis(5-methyltetrazolium)amine-bonded magnetic nanoparticle adsorbent was prepared by chemically modifying magnetic nanoparticles Fe3O4@SiO2 via four steps chemical reactions. The physical properties of the adsorbent were characterized by X-ray photoelectron spectroscopy (XPS) and Zeta potential. The static adsorption behavior of lysozyme, cytochrome C and chymotrypsin on the chelated Cu(Ⅱ) adsorbent, as well as the influences of the pH value of solution, ion strength and initial protein concentration on the adsorption capacity were evaluated with batch method. The results illustrated that the adsorption of protein proceeded via metal coordination mechanism and was also in accordance with Langmuir adsorption model, and the maximum adsorption capacities of lysozyme, cytochrome C and chymotrypsin were calculated to be 20.0 mg/g, 13.5 mg/g, and 17.9 mg/g, respectively. In addition, the chelated Cu(Ⅱ) adsorbent was employed to adsorb protein mixture, showing that this new type of adsorbent had selective adsorption to protein mixture. These results illustrated that the metal-chelated adsorbent had potential application value in selectively separating and enriching proteins.
2016, 44(7): 1125-1132
doi: 10.11895/j.issn.0253-3820.150917
Abstract:
A method for screening of 249 residue compounds of pesticide in foods from the Hongkong's regulation was developed by liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (LC-Q-TOF/MS). The target analytes were dissolved in acetonitrile with 1% formic acid, then extracted and purified by using a modified QuEChERS method. The chromatographic separation was performed on an Agilent Poroshell 120 EC-C18 column (150 mm×3 mm i.d., 2.7 μm) with gradient elution using 0.1% (V/V) formic acid and methanol as mobile phase. The target compounds were monitored under positive ionization mode with ESI source. The matrix effects in 11 kinds of typical foods were considered and the quantification was carried out by matrix-matched with external standard method. Two databases of accurate mass and fragment ions were created. The results demonstrated that the linear range was from 10 μg/kg to 500 μg/kg with good correlation coefficients (r>0.90). The method quantitation limits were in the range of 10-100 μg/kg (S/N≥10). For rices, mushrooms, soybeans, spinaches, tomatoes, broccolies, grapefruits, chives, carrots, lettuces and cucumbers, the average recoveries at three spiked levels were in the range of 23.2%-133.2%, 35.6%-137.6%, and 38.7%-140.2%, and the relative standard deviations (RSDs) were 1.3%-19.2% (n=6). The method is simple, time-saving with high sensitivity and good reproducibility, as well as having practical application for its low test cost.
A method for screening of 249 residue compounds of pesticide in foods from the Hongkong's regulation was developed by liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (LC-Q-TOF/MS). The target analytes were dissolved in acetonitrile with 1% formic acid, then extracted and purified by using a modified QuEChERS method. The chromatographic separation was performed on an Agilent Poroshell 120 EC-C18 column (150 mm×3 mm i.d., 2.7 μm) with gradient elution using 0.1% (V/V) formic acid and methanol as mobile phase. The target compounds were monitored under positive ionization mode with ESI source. The matrix effects in 11 kinds of typical foods were considered and the quantification was carried out by matrix-matched with external standard method. Two databases of accurate mass and fragment ions were created. The results demonstrated that the linear range was from 10 μg/kg to 500 μg/kg with good correlation coefficients (r>0.90). The method quantitation limits were in the range of 10-100 μg/kg (S/N≥10). For rices, mushrooms, soybeans, spinaches, tomatoes, broccolies, grapefruits, chives, carrots, lettuces and cucumbers, the average recoveries at three spiked levels were in the range of 23.2%-133.2%, 35.6%-137.6%, and 38.7%-140.2%, and the relative standard deviations (RSDs) were 1.3%-19.2% (n=6). The method is simple, time-saving with high sensitivity and good reproducibility, as well as having practical application for its low test cost.
2016, 44(7): 1133-1139
doi: 10.11895/j.issn.0253-3820.160202
Abstract:
It is traditionally assumed that enzymatic reaction does not perturb the diffusion of an enzyme iteself. Recent studies have shown that the diffusivity of enzymed increased in a substrate-dependent manner during catalysis. Thus, the energy released during enzyme catalysis can be used to propel nanoscale objects, e.g. molecule motors driven by enzymatic reactions. Although the dependence of enzyme diffusion on substrate has been reported in several different enzyme systems, the precise origin of this phenomenon is still unknown yet. However, sevral possible mechainsms have been proposed for the enhanced diffusion. This review illustrates recent progresses in the research on the influences of enzymatic reaction on the diffusivity of enzyme, including the change of diffusion coefficient of enzymes, potential mechanisms and related applications.
It is traditionally assumed that enzymatic reaction does not perturb the diffusion of an enzyme iteself. Recent studies have shown that the diffusivity of enzymed increased in a substrate-dependent manner during catalysis. Thus, the energy released during enzyme catalysis can be used to propel nanoscale objects, e.g. molecule motors driven by enzymatic reactions. Although the dependence of enzyme diffusion on substrate has been reported in several different enzyme systems, the precise origin of this phenomenon is still unknown yet. However, sevral possible mechainsms have been proposed for the enhanced diffusion. This review illustrates recent progresses in the research on the influences of enzymatic reaction on the diffusivity of enzyme, including the change of diffusion coefficient of enzymes, potential mechanisms and related applications.
2016, 44(7): 1140-1147
doi: 10.11895/j.issn.0253-3820.160004
Abstract:
Separation of the active ingredients of Chinese medicine is always difficult due to its complexity matrix. Recent years, the preparative-high performance liquid chromatography (Pre-HPLC)-based multidimensional chromatography combined with the characteristics of different separation technology improved the separation capability and efficiency, and was applied to the separation and purification of complex traditional Chinese medicine (TCM). In this review, the based principle, separation mode and key technology of preparative-HPLC-based multidimensional chromatography, as well as its application in TCM research were introduced.
Separation of the active ingredients of Chinese medicine is always difficult due to its complexity matrix. Recent years, the preparative-high performance liquid chromatography (Pre-HPLC)-based multidimensional chromatography combined with the characteristics of different separation technology improved the separation capability and efficiency, and was applied to the separation and purification of complex traditional Chinese medicine (TCM). In this review, the based principle, separation mode and key technology of preparative-HPLC-based multidimensional chromatography, as well as its application in TCM research were introduced.
2016, 44(7): 1148-1154
doi: 10.11895/j.issn.0253-3820.160079
Abstract:
By combining electrochemical detection technique and electronic technique, a portable device which adopted differential pulse voltammetry (DPV) measurement was developed to meet the needs of high sensitivity and on-site rapid detection for tumor marker. The voltage and current resolution of portable device were 0.8 mV and 1 nA, respectively. Combined with laboratory made paper-based analytical device, carcinoembryonic antigen(CEA) was tested by portable device. Experimental results revealed that the DPV peak currents showed good linear relation with the logarithm of CEA concentration in the range from 1 μg/L to 500 μg/L. Its corresponding correlation coefficient was 0.998 and the limit of detection was 10 pg/mL. According to the principle of specific binding of antibody and antigen and electrochemical detection, CEA concentration could be calculated automatically according to the linear equation. The portable device had high sensitivity and low detection limit features which could be widely used in the point-of-care testing of tumor marker.
By combining electrochemical detection technique and electronic technique, a portable device which adopted differential pulse voltammetry (DPV) measurement was developed to meet the needs of high sensitivity and on-site rapid detection for tumor marker. The voltage and current resolution of portable device were 0.8 mV and 1 nA, respectively. Combined with laboratory made paper-based analytical device, carcinoembryonic antigen(CEA) was tested by portable device. Experimental results revealed that the DPV peak currents showed good linear relation with the logarithm of CEA concentration in the range from 1 μg/L to 500 μg/L. Its corresponding correlation coefficient was 0.998 and the limit of detection was 10 pg/mL. According to the principle of specific binding of antibody and antigen and electrochemical detection, CEA concentration could be calculated automatically according to the linear equation. The portable device had high sensitivity and low detection limit features which could be widely used in the point-of-care testing of tumor marker.
